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Sample records for carry flea-borne rickettsia

  1. Ixodes ricinus ticks are reservoir hosts for Rickettsia helvetica and potentially carry flea-borne Rickettsia species

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    Gaasenbeek Cor

    2009-09-01

    Full Text Available Abstract Background Hard ticks have been identified as important vectors of rickettsiae causing the spotted fever syndrome. Tick-borne rickettsiae are considered to be emerging, but only limited data are available about their presence in Western Europe, their natural life cycle and their reservoir hosts. Ixodes ricinus, the most prevalent tick species, were collected and tested from different vegetation types and from potential reservoir hosts. In one biotope area, the annual and seasonal variability of rickettsiae infections of the different tick stages were determined for 9 years. Results The DNA of the human pathogen R. conorii as well as R. helvetica, R. sp. IRS and R. bellii-like were found. Unexpectedly, the DNA of the highly pathogenic R. typhi and R. prowazekii and 4 other uncharacterized Rickettsia spp. related to the typhus group were also detected in I. ricinus. The presence of R. helvetica in fleas isolated from small rodents supported our hypothesis that cross-infection can occur under natural conditions, since R. typhi/prowazekii and R. helvetica as well as their vectors share rodents as reservoir hosts. In one biotope, the infection rate with R. helvetica was ~66% for 9 years, and was comparable between larvae, nymphs, and adults. Larvae caught by flagging generally have not yet taken a blood meal from a vertebrate host. The simplest explanation for the comparable prevalence of R. helvetica between the defined tick stages is, that R. helvetica is vertically transmitted through the next generation with high efficiency. The DNA of R. helvetica was also present in whole blood from mice, deer and wild boar. Conclusion Besides R. helvetica, unexpected rickettsiae are found in I. ricinus ticks. We propose that I. ricinus is a major reservoir host for R. helvetica, and that vertebrate hosts play important roles in the further geographical dispersion of rickettsiae.

  2. Detection of flea-borne Rickettsia species in the Western Himalayan region of India.

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    Chahota, R; Thakur, S D; Sharma, M; Mittra, S

    2015-01-01

    Human infections by various rickettsial species are frequently reported globally. We investigated a flea-borne rickettsial outbreak infecting 300 people in Western Himalayan region of India. Arthropod vectors (ticks and fleas) and animal and human blood samples from affected households were analysed by gltA and ompB genes based polymerase chain reaction (PCR). Rat flea (Ceratophyllus fasciatus) samples were found harbouring a Rickettsia sp. Phylogenetic analysis based on gltA gene using PHYLIP revealed that the detected Rickettsia sp. has 100% identity with SE313 and RF2125 strains of Rickettsia sp. of flea origin from Egypt and Thai-Myanmar border, respectively and cf1 and 5 strains from fleas and lice from the USA. But, the nucleotide sequence of genetically variable gene ompB of R14 strain was found closely related to cf9 strain, reported from Ctenocephalides felis fleas. These results highlight the public health importance of such newly discovered or less recognised Rickettsia species/strains, harboured by arthropod vectors like fleas.

  3. Detection of flea-borne Rickettsia species in the Western Himalayan region of India

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    R Chahota

    2015-01-01

    Full Text Available Human infections by various rickettsial species are frequently reported globally. We investigated a flea-borne rickettsial outbreak infecting 300 people in Western Himalayan region of India. Arthropod vectors (ticks and fleas and animal and human blood samples from affected households were analysed by gltA and ompB genes based polymerase chain reaction (PCR. Rat flea (Ceratophyllus fasciatus samples were found harbouring a Rickettsia sp. Phylogenetic analysis based on gltA gene using PHYLIP revealed that the detected Rickettsia sp. has 100% identity with SE313 and RF2125 strains of Rickettsia sp. of flea origin from Egypt and Thai-Myanmar border, respectively and cf1 and 5 strains from fleas and lice from the USA. But, the nucleotide sequence of genetically variable gene ompB of R14 strain was found closely related to cf9 strain, reported from Ctenocephalides felis fleas. These results highlight the public health importance of such newly discovered or less recognised Rickettsia species/strains, harboured by arthropod vectors like fleas.

  4. Rickettsial Infections among Ctenocephalides felis and Host Animals during a Flea-Borne Rickettsioses Outbreak in Orange County, California

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    Fogarty, Carrie; Krueger, Laura; Macaluso, Kevin R.; Odhiambo, Antony; Nguyen, Kiet; Farris, Christina M.; Luce-Fedrow, Alison; Bennett, Stephen; Jiang, Ju; Sun, Sokanary; Cummings, Robert F.; Richards, Allen L.

    2016-01-01

    Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.2% tested positive for Rickettsia. PCR and sequencing of rickettsial genes obtained from C. felis flea DNA preparations revealed the presence of R. typhi (1.3%), R. felis (28.0%) and R. felis-like organisms (7.5%). Sera from opossums contained TGR-specific (40.84%), but not SFGR-specific antibodies. The detection of R. felis and R. typhi in the C. felis fleas in Orange County highlights the potential risk for human infection with either of these pathogens, and underscores the need for further investigations incorporating specimens from humans, animal hosts, and invertebrate vectors in endemic areas. Such studies will be essential for establishing a link in the ongoing flea-borne rickettsioses outbreaks. PMID:27537367

  5. Outbreaks of Rickettsia felis in Kenya and Senegal, 2010

    Centers for Disease Control (CDC) Podcasts

    2010-06-09

    This podcast describes the outbreak of Rickettsia felis in Kenya between August 2006 and June 2008, and in rural Senegal from November 2008 through July 2009. CDC infectious disease pathologist Dr. Chris Paddock discusses what researchers learned about this flea-borne disease and how to prevent infection.  Created: 6/9/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 6/24/2010.

  6. Molecular detection of Rickettsia felis and Candidatus Rickettsia asemboensis in fleas from human habitats, Asembo, Kenya.

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    Jiang, Ju; Maina, Alice N; Knobel, Darryn L; Cleaveland, Sarah; Laudisoit, Anne; Wamburu, Kabura; Ogola, Eric; Parola, Philippe; Breiman, Robert F; Njenga, M Kariuki; Richards, Allen L

    2013-08-01

    The flea-borne rickettsioses murine typhus (Rickettsia typhi) and flea-borne spotted fever (FBSF) (Rickettsia felis) are febrile diseases distributed among humans worldwide. Murine typhus has been known to be endemic to Kenya since the 1950s, but FBSF was only recently documented in northeastern (2010) and western (2012) Kenya. To characterize the potential exposure of humans in Kenya to flea-borne rickettsioses, a total of 330 fleas (134 pools) including 5 species (Xenopsylla cheopis, Ctenocephalides felis, Ctenocephalides canis, Pulex irritans, and Echidnophaga gallinacea) were collected from domestic and peridomestic animals and from human dwellings within Asembo, western Kenya. DNA was extracted from the 134 pooled flea samples and 89 (66.4%) pools tested positively for rickettsial DNA by 2 genus-specific quantitative real-time PCR (qPCR) assays based upon the citrate synthase (gltA) and 17-kD antigen genes and the Rfelis qPCR assay. Sequences from the 17-kD antigen gene, the outer membrane protein (omp)B, and 2 R. felis plasmid genes (pRF and pRFd) of 12 selected rickettsia-positive samples revealed a unique Rickettsia sp. (n=11) and R. felis (n=1). Depiction of the new rickettsia by multilocus sequence typing (MLST) targeting the 16S rRNA (rrs), 17-kD antigen gene, gltA, ompA, ompB, and surface cell antigen 4 (sca4), shows that it is most closely related to R. felis but genetically dissimilar enough to be considered a separate species provisionally named Candidatus Rickettsia asemboensis. Subsequently, 81 of the 134 (60.4%) flea pools tested positively for Candidatus Rickettsia asemboensis by a newly developed agent-specific qPCR assay, Rasemb. R. felis was identified in 9 of the 134 (6.7%) flea pools, and R. typhi the causative agent of murine typhus was not detected in any of 78 rickettsia-positive pools assessed using a species-specific qPCR assay, Rtyph. Two pools were found to contain both R. felis and Candidatus Rickettsia asemboensis DNA and 1 pool

  7. Role of the Yersinia pestis yersiniabactin iron acquisition system in the incidence of flea-borne plague.

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    Florent Sebbane

    Full Text Available Plague is a flea-borne zoonosis caused by the bacterium Yersinia pestis. Y. pestis mutants lacking the yersiniabactin (Ybt siderophore-based iron transport system are avirulent when inoculated intradermally but fully virulent when inoculated intravenously in mice. Presumably, Ybt is required to provide sufficient iron at the peripheral injection site, suggesting that Ybt would be an essential virulence factor for flea-borne plague. Here, using a flea-to-mouse transmission model, we show that a Y. pestis strain lacking the Ybt system causes fatal plague at low incidence when transmitted by fleas. Bacteriology and histology analyses revealed that a Ybt-negative strain caused only primary septicemic plague and atypical bubonic plague instead of the typical bubonic form of disease. The results provide new evidence that primary septicemic plague is a distinct clinical entity and suggest that unusual forms of plague may be caused by atypical Y. pestis strains.

  8. Widespread Rickettsia spp. Infections in Ticks (Acari: Ixodoidea) in Taiwan.

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    Kuo, Chi-Chien; Shu, Pei-Yun; Mu, Jung-Jung; Lee, Pei-Lung; Wu, Yin-Wen; Chung, Chien-Kung; Wang, Hsi-Chieh

    2015-09-01

    Ticks are second to mosquitoes as the most important disease vectors, and recent decades have witnessed the emergence of many novel tick-borne rickettsial diseases, but systematic surveys of ticks and tick-borne rickettsioses are generally lacking in Asia. We collected and identified ticks from small mammal hosts between 2006 and 2010 in different parts of Taiwan. Rickettsia spp. infections in ticks were identified by targeting ompB and gltA genes with nested polymerase chain reaction. In total, 2,732 ticks were collected from 1,356 small mammals. Rhipicephalus haemaphysaloides Supino (51.8% of total ticks), Haemaphysalis bandicota Hoogstraal & Kohls (28.0%), and Ixodes granulatus Supino (20.0%) were the most common tick species, and Rattus losea Swinhoe (44.7% of total ticks) and Bandicota indica Bechstein (39.9%) were the primary hosts. The average Rickettsia infective rate in 329 assayed ticks was 31.9% and eight Rickettsia spp. or closely related species were identified. This study shows that rickettsiae-infected ticks are widespread in Taiwan, with a high diversity of Rickettsia spp. circulating in the ticks. Because notifiable rickettsial diseases in Taiwan only include mite-borne scrub typhus and flea-borne murine typhus, more studies are warranted for a better understanding of the real extent of human risks to rickettsioses in Taiwan.

  9. Rickettsia felis, an emerging flea-transmitted human pathogen

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    Stephen Graves

    2011-07-01

    Full Text Available Rickettsia felis was first recognised two decades ago and has now been described as endemic to all continents except Antarctica. The rickettsiosis caused by R. felis is known as flea-borne spotted fever or cat-flea typhus. The large number of arthropod species found to harbour R. felis and that may act as potential vectors support the view that it is a pan-global microbe. The main arthropod reservoir and vector is the cat flea, Ctenocephalides felis, yet more than 20 other species of fleas, ticks, and mites species have been reported to harbour R. felis. Few bacterial pathogens of humans have been found associated with such a diverse range of invertebrates. With the projected increase in global temperature over the next century, there is concern that changes to the ecology and distribution of R. felis vectors may adversely impact public health.

  10. An update on the detection and treatment of Rickettsia felis

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    Hun L

    2012-06-01

    Full Text Available Laya Hun, Adriana TroyoCentro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa RicaAbstract: Rickettsia felis was described as a human pathogen almost two decades ago, and human infection is currently reported in 18 countries in all continents. The distribution of this species is worldwide, determined by the presence of the main arthropod vector, Ctenocephalides felis (Bouché. The list of symptoms, which includes fever, headache, myalgia, and rash, keeps increasing as new cases with unexpected symptoms are described. Moreover, the clinical presentation of R. felis infection can be easily confused with many tropical and nontropical diseases, as well as other rickettsial infections. Although specific laboratory diagnosis and treatment for this flea-borne rickettsiosis are detailed in the scientific literature, it is possible that most human cases are not being diagnosed properly. Furthermore, since the cat flea infests different common domestic animals, contact with humans may be more frequent than reported. In this review, we provide an update on methods for specific detection of human infection by R. felis described in the literature, as well as the treatment prescribed to the patients. Considering advances in molecular detection tools, as well as options for as-yet-unreported isolation of R. felis from patients in cell culture, increased diagnosis and characterization of this emerging pathogen is warranted.Keywords: Rickettsia felis, human cases, laboratory diagnosis, treatment

  11. Progress in research of Rickettsia felis%猫立克次体研究进展

    Institute of Scientific and Technical Information of China (English)

    刘杨; 杨雨; 陈萍; 赵锋; 钟玮

    2015-01-01

    猫立克次体(Rickettsia felis)可以引起蚤传斑点热(Flea-Borne Spotted Fever,FBSF),主要传播媒介是猫蚤(Ctenocephalides felis).自上世纪90年代首次发现以来,已被证实分布于地球上除南极以外的各大洲.本文对猫立克次体的传播媒介、检测方法以及基因组学研究进展进行了综述,并讨论了在全球气候变化的背景下,开展猫立克次体研究的重要意义.

  12. Detection of Rickettsia felis, Rickettsia typhi, Bartonella Species and Yersinia pestis in Fleas (Siphonaptera from Africa.

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    Hamza Leulmi

    2014-10-01

    Full Text Available Little is known about the presence/absence and prevalence of Rickettsia spp, Bartonella spp. and Yersinia pestis in domestic and urban flea populations in tropical and subtropical African countries.Fleas collected in Benin, the United Republic of Tanzania and the Democratic Republic of the Congo were investigated for the presence and identity of Rickettsia spp., Bartonella spp. and Yersinia pestis using two qPCR systems or qPCR and standard PCR. In Xenopsylla cheopis fleas collected from Cotonou (Benin, Rickettsia typhi was detected in 1% (2/199, and an uncultured Bartonella sp. was detected in 34.7% (69/199. In the Lushoto district (United Republic of Tanzania, R. typhi DNA was detected in 10% (2/20 of Xenopsylla brasiliensis, and Rickettsia felis was detected in 65% (13/20 of Ctenocephalides felis strongylus, 71.4% (5/7 of Ctenocephalides canis and 25% (5/20 of Ctenophthalmus calceatus calceatus. In the Democratic Republic of the Congo, R. felis was detected in 56.5% (13/23 of Ct. f. felis from Kinshasa, in 26.3% (10/38 of Ct. f. felis and 9% (1/11 of Leptopsylla aethiopica aethiopica from Ituri district and in 19.2% (5/26 of Ct. f. strongylus and 4.7% (1/21 of Echidnophaga gallinacea. Bartonella sp. was also detected in 36.3% (4/11 of L. a. aethiopica. Finally, in Ituri, Y. pestis DNA was detected in 3.8% (1/26 of Ct. f. strongylus and 10% (3/30 of Pulex irritans from the villages of Wanyale and Zaa.Most flea-borne infections are neglected diseases which should be monitored systematically in domestic rural and urban human populations to assess their epidemiological and clinical relevance. Finally, the presence of Y. pestis DNA in fleas captured in households was unexpected and raises a series of questions regarding the role of free fleas in the transmission of plague in rural Africa, especially in remote areas where the flea density in houses is high.

  13. Carry

    DEFF Research Database (Denmark)

    Koijen, Ralph S.J.; Moskowitz, Tobias J.; Heje Pedersen, Lasse;

    that include global equities, global bonds, currencies, commodities, US Treasuries, credit, and equity index options. This predictability underlies the strong returns to "carry trades" that go long high-carry and short low-carry securities, applied almost exclusively to currencies, but shown here...

  14. Prevalence of Bartonella species, hemoplasmas, and Rickettsia felis DNA in blood and fleas of cats in Bangkok, Thailand.

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    Assarasakorn, S; Veir, J K; Hawley, J R; Brewer, M M; Morris, A K; Hill, A E; Lappin, M R

    2012-12-01

    Flea infestations are common in Thailand, but little is known about the flea-borne infections. Fifty flea pools and 153 blood samples were collected from client-owned cats between June and August 2009 from veterinary hospitals in Bangkok, Thailand. Total DNA was extracted from all samples, and then assessed by conventional PCR assays. The prevalence rates of Bartonella spp. in blood and flea samples were 17% and 32%, respectively, with DNA of Bartonella henselae and Bartonella clarridgeiae being amplified most commonly. Bartonella koehlerae DNA was amplified for the first time in Thailand. Hemoplasma DNA was amplified from 23% and 34% of blood samples and flea pools, respectively, with 'Candidatus Mycoplasma haemominutum' and Mycoplasma haemofelis being detected most frequently. All samples were negative for Rickettsia felis. Prevalence rate of B. henselae DNA was increased 6.9 times in cats with flea infestation. Cats administered flea control products were 4.2 times less likely to be Bartonella-infected.

  15. Rickettsia africae and Candidatus Rickettsia barbariae in ticks in Israel.

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    Waner, Trevor; Keysary, Avi; Eremeeva, Marina E; Din, Adi Beth; Mumcuoglu, Kosta Y; King, Roni; Atiya-Nasagi, Yafit

    2014-05-01

    DNA of several spotted fever group rickettsiae was found in ticks in Israel. The findings include evidence for the existence of Rickettsia africae and Candidatus Rickettsia barbariae in ticks in Israel. The DNA of R. africae was detected in a Hyalomma detritum tick from a wild boar and DNA of C. Rickettsia barbariae was detected in Rhipicephalus turanicus and Rhipicephalus sanguineus collected from vegetation. The DNA of Rickettsia massiliae was found in Rh. sanguineus and Haemaphysalis erinacei, whereas DNA of Rickettsia sibirica mongolitimonae was detected in a Rhipicephalus (Boophilus) annulatus. Clinicians should be aware that diseases caused by a variety of rickettsiae previously thought to be present only in other countries outside of the Middle East may infect residents of Israel who have not necessarily traveled overseas. Furthermore, this study reveals again that the epidemiology of the spotted fever group rickettsiae may not only involve Rickettsia conorii but may include other rickettsiae.

  16. Molecular detection of Rickettsia africae, Rickettsia aeschlimannii, and Rickettsia sibirica mongolitimonae in camels and Hyalomma spp. ticks from Israel.

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    Kleinerman, Gabriela; Baneth, Gad; Mumcuoglu, Kosta Y; van Straten, Michael; Berlin, Dalia; Apanaskevich, Dmitry A; Abdeen, Ziad; Nasereddin, Abed; Harrus, Shimon

    2013-12-01

    In this study, we aimed to identify and genetically characterize spotted fever group (SFG) rickettsiae in ticks, domestic one-humped camels, and horses from farms and Bedouin communities in southern Israel. A total of 618 ixodid ticks (Hyalomma dromedarii, Hyalomma turanicum, Hyalomma excavatum, and Hyalomma impeltatum) collected from camels and horses, as well as 152 blood samples from 148 camels and four horses were included in the study. Initial screening for rickettsiae was carried out by targeting the gltA gene. Positive samples were further analyzed for rickettsial ompA, 17kDa, ompB, and 16S rRNA genes. Rickettsia aeschlimannii DNA was detected in the blood of three camels and 14 ticks (H. dromedarii, H. turanicum, and H. excavatum). Rickettsia africae was found in six ticks (H. turanicum, H. impeltatum, H. dromedarii, and H. excavatum). In addition, Rickettsia sibirica mongolitimonae was detected in one H. turanicum tick. These findings represent the first autochthonous detection of R. africae in Israel. Previous detections of R. africae in Asia were reported from the Sinai Peninsula (Egypt) and Istanbul, only. Furthermore, we report for the first time the finding of R. aeschlimannii in H. turanicum and H. excavatum ticks, as well as the first identification of R. sibirica mongolitimonae in H. turanicum ticks. The tick species identified to harbor R. africae and other SFG rickettsiae have been reported to occasionally feed on people, and, therefore, physicians should be aware of the possible exposure of local communities and travelers, especially those in contact with camels, to these tick-borne rickettsial pathogens.

  17. Absence of zoonotic Bartonella species in questing ticks: First detection of Bartonella clarridgeiae and Rickettsia felis in cat fleas in the Netherlands

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    Reimerink Johan R

    2011-04-01

    Full Text Available Abstract Background Awareness for flea- and tick-borne infections has grown in recent years and the range of microorganisms associated with these ectoparasites is rising. Bartonella henselae, the causative agent of Cat Scratch Disease, and other Bartonella species have been reported in fleas and ticks. The role of Ixodes ricinus ticks in the natural cycle of Bartonella spp. and the transmission of these bacteria to humans is unclear. Rickettsia spp. have also been reported from as well ticks as also from fleas. However, to date no flea-borne Rickettsia spp. were reported from the Netherlands. Here, the presence of Bartonellaceae and Rickettsiae in ectoparasites was investigated using molecular detection and identification on part of the gltA- and 16S rRNA-genes. Results The zoonotic Bartonella clarridgeiae and Rickettsia felis were detected for the first time in Dutch cat fleas. B. henselae was found in cat fleas and B. schoenbuchensis in ticks and keds feeding on deer. Two Bartonella species, previously identified in rodents, were found in wild mice and their fleas. However, none of these microorganisms were found in 1719 questing Ixodes ricinus ticks. Notably, the gltA gene amplified from DNA lysates of approximately 10% of the questing nymph and adult ticks was similar to that of an uncultured Bartonella-related species found in other hard tick species. The gltA gene of this Bartonella-related species was also detected in questing larvae for which a 16S rRNA gene PCR also tested positive for "Candidatus Midichloria mitochondrii". The gltA-gene of the Bartonella-related species found in I. ricinus may therefore be from this endosymbiont. Conclusions We conclude that the risk of acquiring Cat Scratch Disease or a related bartonellosis from questing ticks in the Netherlands is negligible. On the other hand fleas and deer keds are probable vectors for associated Bartonella species between animals and might also transmit Bartonella spp. to humans.

  18. Novel rickettsia in ticks, Tasmania, Australia.

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    Izzard, Leonard; Graves, Stephen; Cox, Erika; Fenwick, Stan; Unsworth, Nathan; Stenos, John

    2009-10-01

    A novel rickettsia was detected in Ixodes tasmani ticks collected from Tasmanian devils. A total of 55% were positive for the citrate synthase gene by quantitative PCR. According to current criteria for rickettsia speciation, this new rickettsia qualifies as Candidatus Rickettsia tasmanensis, named after the location of its detection.

  19. Immunoproteomic profiling of Rickettsia parkeri and Rickettsia amblyommii.

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    Pornwiroon, Walairat; Bourchookarn, Apichai; Paddock, Christopher D; Macaluso, Kevin R

    2015-09-01

    Rickettsia parkeri is an Amblyomma-associated, spotted fever group Rickettsia species that causes an eschar-associated, febrile illness in multiple countries throughout the Western Hemisphere. Many other rickettsial species of known or uncertain pathogenicity have been detected in Amblyomma spp. ticks in the Americas, including Rickettsia amblyommii, "Candidatus Rickettsia andeanae" and Rickettsia rickettsii. In this study, we utilized an immunoproteomic approach to compare antigenic profiles of low-passage isolates of R. parkeri and R. amblyommii with serum specimens from patients with PCR- and culture-confirmed infections with R. parkeri. Five immunoreactive proteins of R. amblyommii and nine immunoreactive proteins of R. parkeri were identified by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. Four of these, including the outer membrane protein (Omp) A, OmpB, translation initiation factor IF-2, and cell division protein FtsZ, were antigens common to both rickettsiae. Serum specimens from patients with R. parkeri rickettsiosis reacted specifically with cysteinyl-tRNA synthetase, DNA-directed RNA polymerase subunit alpha, putative sigma (54) modulation protein, chaperonin GroEL, and elongation factor Tu of R. parkeri which have been reported as virulence factors in other bacterial species. Unique antigens identified in this study may be useful for further development of the better serological assays for diagnosing infection caused by R. parkeri.

  20. Dose-response model of murine typhus (Rickettsia typhi: time post inoculation and host age dependency analysis

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    Tamrakar Sushil B

    2012-03-01

    Full Text Available Abstract Background Rickettsia typhi (R. mooseri is the causative agent of murine typhus. It is one of the most widely distributed flea-borne diseases with a relatively mild febrile initial illness with six to 14 days of incubation period. The bacterium is gram negative and an obligate intracellular pathogen. The disease is transmitted to humans and vertebrate host through fleabites or via contact with infected feces. This paper develops dose-response models of different routes of exposure for typhus in rodents. Methods Data from published articles were analyzed using parametric dose-response relationship models. Dose-response relationships were fit to data using the method of maximum likelihood estimation (MLE. Results Dose-response models quantifying the effects of different ages of rats and time post inoculation in BALB/c mice were analyzed in the study. Both the adult rats (inoculated intradermally and newborn rats (inoculated subcutaneously were best fit by exponential models and both distributions could be described by a single dose-response relationship. The BALB/C mice inoculated subcutaneously were best fit by Beta-Poisson models. The time post inoculation analysis showed that there was a definite time and response relationship existed in this case. Conclusions Intradermally or subcutaneously inoculated rats (adult and newborn models suggest that less than 1 plaque-forming unit (PFU (1.33 to 0.38 in 95% confidence limits of the pathogen is enough to seroconvert 50% of the exposed population on average. For the BALB/c mouse time post inoculation model, an average dose of 0.28 plaque-forming units (PFU (0.75 to 0.11 in 95% confidence limits will seroconvert 50% of the exposed mice.

  1. Electrotransformation and Clonal Isolation of Rickettsia Species.

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    Riley, Sean P; Macaluso, Kevin R; Martinez, Juan J

    2015-11-03

    Genetic manipulation of obligate intracellular bacteria of the genus Rickettsia is currently undergoing a rapid period of change. The development of viable genetic tools, including replicative plasmids, transposons, homologous recombination, fluorescent protein-encoding genes, and antibiotic selectable markers has provided the impetus for future research development. This unit is designed to coalesce the basic methods pertaining to creation of genetically modified Rickettsia. The unit describes a series of methods, from inserting exogenous DNA into Rickettsia to the final isolation of genetically modified bacterial clones. Researchers working towards genetic manipulation of Rickettsia or similar obligate intracellular bacteria will find these protocols to be a valuable reference.

  2. Genome sequence of Rickettsia bellii illuminates the role of amoebae in gene exchanges between intracellular pathogens.

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    2006-05-01

    Full Text Available The recently sequenced Rickettsia felis genome revealed an unexpected plasmid carrying several genes usually associated with DNA transfer, suggesting that ancestral rickettsiae might have been endowed with a conjugation apparatus. Here we present the genome sequence of Rickettsia bellii, the earliest diverging species of known rickettsiae. The 1,552,076 base pair-long chromosome does not exhibit the colinearity observed between other rickettsia genomes, and encodes a complete set of putative conjugal DNA transfer genes most similar to homologues found in Protochlamydia amoebophila UWE25, an obligate symbiont of amoebae. The genome exhibits many other genes highly similar to homologues in intracellular bacteria of amoebae. We sought and observed sex pili-like cell surface appendages for R. bellii. We also found that R. bellii very efficiently multiplies in the nucleus of eukaryotic cells and survives in the phagocytic amoeba, Acanthamoeba polyphaga. These results suggest that amoeba-like ancestral protozoa could have served as a genetic "melting pot" where the ancestors of rickettsiae and other bacteria promiscuously exchanged genes, eventually leading to their adaptation to the intracellular lifestyle within eukaryotic cells.

  3. Integrated morphological and molecular identification of cat fleas (Ctenocephalides felis) and dog fleas (Ctenocephalides canis) vectoring Rickettsia felis in central Europe.

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    Lawrence, Andrea L; Hii, Sze-Fui; Jirsová, Dagmar; Panáková, Lucia; Ionică, Angela M; Gilchrist, Katrina; Modrý, David; Mihalca, Andrei D; Webb, Cameron E; Traub, Rebecca J; Šlapeta, Jan

    2015-06-15

    Fleas of the genus Ctenocephalides are the most common ectoparasites infesting dogs and cats world-wide. The species Ctenocephalides felis and Ctenocephalides canis are competent vectors for zoonotic pathogens such as Rickettsia felis and Bartonella spp. Improved knowledge on the diversity and phylogenetics of fleas is important for understanding flea-borne pathogen transmission cycles. Fleas infesting privately owned dogs and cats from the Czech Republic (n=97) and Romania (n=66) were subjected to morphological and molecular identification and phylogenetic analysis. There were a total of 59 (60.82%) cat fleas (Ctenocephalides felis felis), 30 (30.93%) dog fleas (Ctenocephalides canis), 7 (7.22%) European chicken fleas (Ceratophyllus gallinae) and 1 (1.03%) northern rat flea (Nosopsyllus fasciatus) collected in the Czech Republic. Both C. canis and C. felis felis were identified in Romania. Mitochondrial DNA sequencing at the cox1 gene on a cohort of 40 fleas revealed the cosmopolitan C. felis felis clade represented by cox1 haplotype 1 is present in the Czech Republic. A new C. felis felis clade from both the Czech Republic and Romania is also reported. A high proportion of C. canis was observed from dogs and cats in the current study and phylogeny revealed that C. canis forms a sister clade to the oriental cat flea Ctenocephalides orientis (syn. C. felis orientis). Out of 33 fleas tested, representing C. felis felis, C. canis and Ce. gallinae, 7 (21.2%) were positive for R. felis using diagnostic real-time PCR targeting the gltA gene and a conventional PCR targeting the ompB gene. No samples tested positive for Bartonella spp. using a diagnostic real-time PCR assay targeting ssrA gene. This study confirms high genetic diversity of C. felis felis globally and serves as a foundation to understand the implication for zoonotic disease carriage and transmission by the flea genus Ctenocephalides.

  4. Isolation of the rickettsial agent genetically similar to Candidatus Rickettsia kotlanii, from Haemaphysalis megaspinosa in Japan.

    Science.gov (United States)

    Andoh, Masako; Ogasawara, Yumiko; Sakata, Akiko; Ito, Takuya; Fujita, Hiromi; Kawabata, Hiroki; Ando, Shuji

    2014-09-01

    Two rickettsial isolates, HM-1 and HM-2, were isolated from Haemaphysalis megaspinosa collected in Japan in 2006 and 2011, respectively. The isolates were analyzed by DNA sequences of the outer membrane protein A gene, the outer membrane protein B gene, the citrate synthase gene, the genus Rickettsia-specific outer membrane protein 17-kDa gene, the 16S ribosome RNA gene, and the PS120 protein gene ("geneD"). HM-1 was identified as Rickettsia tamurae. HM-2 matched most closely with 'Candidatus Rickettsia kotlanii' DNA, which has only been reported from H. concinna in Hungary. This is the first report of isolation in Japan of the agent genetically similar to 'Candidatus R. kotlanii,' which belongs phylogenetically to the spotted fever group Rickettsia. Our study shows the possibility that 'Candidatus R. kotlanii' can be carried by at least two tick species. Furthermore, because the Rickettsia sp. has been found two distant countries, Hungary and Japan, it has potential for wider distribution.

  5. Detection of Rickettsia helvetica in Ixodes ricinus ticks collected from Pyrenean chamois in France.

    Science.gov (United States)

    Davoust, Bernard; Socolovschi, Cristina; Revelli, Paul; Gibert, Philippe; Marié, Jean-Lou; Raoult, Didier; Parola, Philippe

    2012-12-01

    Seventy-one Ixodes ricinus ticks collected from Pyrenean chamois (Rupicapra pyrenaica) in the French Pyrenees were tested by real-time polymerase chain reaction to detect the presence of Rickettsia and Bartonella. Four ticks (6%) were positive for R. helvetica. The chamois carries infected ticks, and this enables the dissemination throughout the environment with this bacterium, a potential human pathogen.

  6. Exotic Rickettsiae in Ixodes ricinus: fact or artifact?

    NARCIS (Netherlands)

    Tijsse-Klasen, E.; Fonville, M.; Overbeek, van L.S.; Reimerink, J.H.J.; Sprong, H.

    2010-01-01

    Several pathogenic Rickettsia species can be transmitted via Ixodes ricinus ticks to humans and animals. Surveys of I. ricinus for the presence of Rickettsiae using part of its 16S rRNA gene yield a plethora of new and different Rickettsia sequences. Interpreting these data is sometimes difficult an

  7. 21 CFR 866.3500 - Rickettsia serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rickettsia serological reagents. 866.3500 Section... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500 Rickettsia serological reagents. (a) Identification. Rickettsia serological reagents are devices that consist of...

  8. The Rickettsia Endosymbiont of Ixodes pacificus Contains All the Genes of De Novo Folate Biosynthesis.

    Directory of Open Access Journals (Sweden)

    Daniel J Hunter

    Full Text Available Ticks and other arthropods often are hosts to nutrient providing bacterial endosymbionts, which contribute to their host's fitness by supplying nutrients such as vitamins and amino acids. It has been detected, in our lab, that Ixodes pacificus is host to Rickettsia species phylotype G021. This endosymbiont is predominantly present, and 100% maternally transmitted in I. pacificus. To study roles of phylotype G021 in I. pacificus, bioinformatic and molecular approaches were carried out. MUMmer genome alignments of whole genome sequence of I. scapularis, a close relative to I. pacificus, against completely sequenced genomes of R. bellii OSU85-389, R. conorii, and R. felis, identified 8,190 unique sequences that are homologous to Rickettsia sequences in the NCBI Trace Archive. MetaCyc metabolic reconstructions revealed that all folate gene orthologues (folA, folC, folE, folKP, ptpS required for de novo folate biosynthesis are present in the genome of Rickettsia buchneri in I. scapularis. To examine the metabolic capability of phylotype G021 in I. pacificus, genes of the folate biosynthesis pathway of the bacterium were PCR amplified using degenerate primers. BLAST searches identified that nucleotide sequences of the folA, folC, folE, folKP, and ptpS genes possess 98.6%, 98.8%, 98.9%, 98.5% and 99.0% identity respectively to the corresponding genes of Rickettsia buchneri. Phylogenetic tree constructions show that the folate genes of phylotype G021 and homologous genes from various Rickettsia species are monophyletic. This study has shown that all folate genes exist in the genome of Rickettsia species phylotype G021 and that this bacterium has the genetic capability for de novo folate synthesis.

  9. Molecular detection of Rickettsia conorii and other zoonotic spotted fever group rickettsiae in ticks, Romania.

    Science.gov (United States)

    Ionita, Mariana; Silaghi, Cornelia; Mitrea, Ioan Liviu; Edouard, Sophie; Parola, Philippe; Pfister, Kurt

    2016-02-01

    The diverse tick fauna as well as the abundance of tick populations in Romania represent potential risks for both human and animal health. Spotted fever group (SFG) rickettsiae are recognized as important agents of emerging human tick-borne diseases worldwide. However, the epidemiology of rickettsial diseases has been poorly investigated in Romania. In urban habitats, companion animals which are frequently exposed to tick infestation, play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Therefore, the aim of the present study was to investigate the occurrence of SFG rickettsiae in ticks infesting dogs in a greater urban area in South-eastern Romania. Adult ixodid ticks (n=205), including Rhipicephalus sanguineus sensu lato (n=120), Dermacentor reticulatus (n=76) and Ixodes ricinus (n=9) were collected from naturally infested dogs and were screened for SFG rickettsiae using conventional PCR followed by sequencing. Additionally, ticks were screened for DNA of Babesia spp., Hepatozoon spp., Ehrlichia canis, and Anaplasma platys. Four zoonotic SFG rickettsiae were identified: Rickettsia raoultii (16%) and Rickettsia slovaca (3%) in D. reticulatus, Rickettsia monacensis (11%) in I. ricinus, and Rickettsia conorii (0.8%) in Rh. sanguineus s.l. Moreover, pathogens of veterinary importance, such as B. canis (21%) in D. reticulatus and E. canis (7.5%) in Rh. sanguineus s.l. were identified. The findings expand the knowledge on distribution of SFG rickettsiae as well as canine pathogens in Romania. Additionally, this is the first report describing the molecular detection of R. conorii in ticks from Romania.

  10. Rickettsia raoultii, the predominant Rickettsia found in Dermacentor silvarum ticks in China-Russia border areas.

    Science.gov (United States)

    Wen, Jing; Jiao, Dan; Wang, Jian-Hua; Yao, De-Hai; Liu, Zhi-Xiang; Zhao, Gang; Ju, Wen-Dong; Cheng, Cheng; Li, Yi-Jing; Sun, Yi

    2014-08-01

    Since the year 2000, clinical patterns resembling tick-borne rickettsioses have been noticed in China-Russia border areas. Epidemiological data regarding species of the aetiological agent, tick vector prevalence and distribution as well as incidence of human cases in the areas are still sparse to date. In order to identify Rickettsia species occurring in the areas, we investigated Dermacentor silvarum collected in the selected areas. Rickettsia raoultii was the predominant Rickettsia found in D. silvarum evident with ompA, ompB, gltA and 17 kDa protein genes. The Rickettsia prevalence in D. silvarum appeared to be 32.25 % with no sex difference. The results extend the common knowledge about the geographic distribution of R. raoultii and its candidate vector tick species, which suggest an emerged potential threat of human health in the areas.

  11. First report on the occurrence of Rickettsia slovaca and Rickettsia raoultii in Dermacentor silvarum in China

    Directory of Open Access Journals (Sweden)

    Tian Zhan-Cheng

    2012-01-01

    Full Text Available Abstract Background Rickettsioses are among both the longest known and most recently recognized infectious diseases. Although new spotted fever group rickettsiae have been isolated in many parts of the world including China, Little is known about the epidemiology of Rickettsia pathogens in ticks from Xinjiang Autonomous Region of China. Methods In an attempt to assess the potential risk of rickettsial infection after exposure to ticks in Xinjiang Uygur Autonomous Region of China, a total of 200 Dermacentor silvarum ticks collected in Xinyuan district were screened by polymerase chain reaction based on the outer membrane protein A gene. Results 22 of the 200 specimens (11% were found to be positive by PCR. Phylogenetic analysis of OmpA sequences identified two rickettsial species, Rickettsia raoultii (4.5% and Rickettsia slovaca (6.5%. Conclusions This study has reported the occurrence of Rickettsia raoultii and Rickettsia slovaca in Xinjiang Autonomous Region of China and suggests that Dermacentor silvarum could be involved in the transmission of rickettsial agents in China. Further studies on the characterization and culture of rickettsial species found in Dermacentor silvarum should be performed to further clarify this. Additionally, the screening of human specimens for rickettsial disease in this region will define the incidence of infection.

  12. Rickettsia slovaca infection in humans, Portugal.

    Science.gov (United States)

    de Sousa, Rita; Pereira, Branca Isabel; Nazareth, Claúdia; Cabral, Susana; Ventura, Conceição; Crespo, Pedro; Marques, Nuno; da Cunha, Saraiva

    2013-10-01

    Fifteen years after the initial detection of Rickettsia slovaca in ticks in Portugal, 3 autochthonous cases of R. slovaca infection were diagnosed in humans. All patients had an eschar on the scalp and lymphadenopathy; 2 patients had facial edema. R. slovaca infection was confirmed by serologic testing, culture, and PCR.

  13. Human infections with Rickettsia raoultii, China.

    Science.gov (United States)

    Jia, Na; Zheng, Yuan-Chun; Ma, Lan; Huo, Qiu-Bo; Ni, Xue-Bing; Jiang, Bao-Gui; Chu, Yan-Li; Jiang, Rui-Ruo; Jiang, Jia-Fu; Cao, Wu-Chun

    2014-05-01

    We used molecular methods to identify Rickettsia raoultii infections in 2 persons in China. These persons had localized rashes around sites of tick bites. R. raoultii DNA was detected in 4% of Dermacentor silvarum ticks collected in the same area of China and in 1 feeding tick detached from 1 patient.

  14. Genotypic and biological characteristics of non-identified strain of spotted fever group rickettsiae isolated in Crimea.

    Science.gov (United States)

    Balayeva, N M; Demkin, V V; Rydkina, E B; Ignatovich, V F; Artemiev, M I; Lichoded LYa; Genig, V A

    1993-12-01

    A strain of rickettsiae, designated Crimea-108, was isolated from ticks Dermacentor marginatus in the Crimea in 1977. Its immunobiological characteristics involve low pathogenicity for experimental animals, moderate infectivity for chick embryos, and antigenic relatedness to spotted fever group (SFG) rickettsiae (R. sibirica, R. conorii, R. akari), especially to R. sibirica. The genotypic characterization of the strain Crimea-108 was carried out in comparison with SFG and typhus group rickettsiae by using restriction fragment length polymorphism (RFLP) analysis and DNA-probe hybridization. The marked similarity was detected between DNA restriction patterns of the strains Crimea-108, R. sibirica and R. conorii, but each of them besides comigrating fragments had specific ones. Genotypic analysis of the strain Crimea-108, the SFG and typhus group rickettsiae by three independent DNA probes, based on R. prowazekii DNA, gave unique hybridization patterns for the Crimea-108 strain with all probes. The obtained data show that the Crimea-108 isolate does not belong to the species of R. sibirica, R. conorii, R. akari. The strain Crimea-108 is a novel strain of SFG rickettsiae for the Crimea region.

  15. Detection of Rickettsia and Anaplasma from hard ticks in Thailand.

    Science.gov (United States)

    Malaisri, Premnika; Hirunkanokpun, Supanee; Baimai, Visut; Trinachartvanit, Wachareeporn; Ahantarig, Arunee

    2015-12-01

    We collected a total of 169 adult hard ticks and 120 nymphs from under the leaves of plants located along tourist nature trails in ten localities. The results present data examining the vector competence of ticks of different genera and the presence of Rickettsia and Anaplasma species. The ticks belonged to three genera, Amblyomma, Dermacentor, and Haemaphysalis, comprising 11 species. Rickettsia bacteria were detected at three collection sites, while Anaplasma bacteria were detected at only one site. Phylogenetic analysis revealed new rickettsia genotypes from Thailand that were closely related to Rickettsia tamurae, Rickettsia monacensis, and Rickettsia montana. This study was also the first to show that Anaplasma bacteria are found in Haemaphysalis shimoga ticks and are closely related evolutionarily to Anaplasma bovis. These results provide additional information for the geographical distribution of tick species and tick-borne bacteria in Thailand and can therefore be applied for ecotourism management.

  16. Rickettsia influences thermotolerance in the whitefly Bemisia tabaci B biotype

    Institute of Scientific and Technical Information of China (English)

    Marina Brumin; Svetlana Kontsedalov; Murad Ghanim

    2011-01-01

    The whitefly Bemisia tabaci harbors Portiera aleyrodidarum,an obligatory symbiotic bacterium,as well as several secondary symbionts,including Rickettsia,Hamiltonella,Wolbachia,Arsenophonus,Cardinium and Fritschea,the function of which is unknown.In Israel,Rickettsia is found in both the B and Q of B.tabaci biotypes,and while all other secondary symbionts are located in the bacteriomes,Rickettsia can occupy most of the body cavity of the insect.We tested whether Rickettsia influences the biology of B.tabaci and found that exposing a Rickettsia-containing population to increasing temperatures significantly increases its tolerance to heat shock that reached 40℃,compared to a Rickettsia-free population.This increase in tolerance to heat shock was not associated with specific induction of heat-shock protein gene expression; however,it was associated with eduction in Rickettsia numbers as was assessed by quantitative real-time polymerase chain reaction and fluorescence in situ hybridization analyses.To assess the causes for thermotolerance when ickettsia is reduced,we tested whether its presence is associated with the induction of genes required for thermotolerance.We found that under normal 25℃ rearing temperature,genes associated with response to stress such as cytoskeleton genes are induced in the Rickettsia-containing population.Thus,the presence of Rickettsia in B.tabaci under normal conditions induces the expression of genes required for thermotolerance that under high temperatures indirectly lead to this tolerance.

  17. Rickettsia typhi and Rickettsia felis in Xenopsylla cheopis and Leptopsylla segnis parasitizing rats in Cyprus.

    Science.gov (United States)

    Christou, Christos; Psaroulaki, Anna; Antoniou, Maria; Toumazos, Pavlos; Ioannou, Ioannis; Mazeris, Apostolos; Chochlakis, Dimosthenis; Tselentis, Yannis

    2010-12-01

    Fleas collected from rats during a three-year period (2000-2003) in 51 areas of all provinces of Cyprus were tested by molecular analysis to characterize the prevalence and identity of fleaborne rickettsiae. Rickettsia typhi, the causative agent of murine typhus, was detected in Xenopsylla cheopis (4%) and in Leptopsylla segnis (6.6%). Rickettsia felis was detected in X. cheopis (1%). This is the first report of R. typhi in X. cheopis and L. segnis from rats, in Cyprus, and the first report of R. felis in X. cheopis in Europe. The role of fleas (mainly X. cheopis) was confirmed in the epidemiologic cycle of murine typhus in Cyprus by interrelation of current results with those of previous studies. The geographic distribution of fleas coincided with the geographic distribution of the pathogen they can harbor, which emphasizes the potential risk of flea-transmitted infections in Cyprus.

  18. Plasmids and rickettsial evolution: insight from Rickettsia felis.

    Directory of Open Access Journals (Sweden)

    Joseph J Gillespie

    Full Text Available BACKGROUND: The genome sequence of Rickettsia felis revealed a number of rickettsial genetic anomalies that likely contribute not only to a large genome size relative to other rickettsiae, but also to phenotypic oddities that have confounded the categorization of R. felis as either typhus group (TG or spotted fever group (SFG rickettsiae. Most intriguing was the first report from rickettsiae of a conjugative plasmid (pRF that contains 68 putative open reading frames, several of which are predicted to encode proteins with high similarity to conjugative machinery in other plasmid-containing bacteria. METHODOLOGY/PRINCIPAL FINDINGS: Using phylogeny estimation, we determined the mode of inheritance of pRF genes relative to conserved rickettsial chromosomal genes. Phylogenies of chromosomal genes were in agreement with other published rickettsial trees. However, phylogenies including pRF genes yielded different topologies and suggest a close relationship between pRF and ancestral group (AG rickettsiae, including the recently completed genome of R. bellii str. RML369-C. This relatedness is further supported by the distribution of pRF genes across other rickettsiae, as 10 pRF genes (or inactive derivatives also occur in AG (but not SFG rickettsiae, with five of these genes characteristic of typical plasmids. Detailed characterization of pRF genes resulted in two novel findings: the identification of oriV and replication termination regions, and the likelihood that a second proposed plasmid, pRFdelta, is an artifact of the original genome assembly. CONCLUSION/SIGNIFICANCE: Altogether, we propose a new rickettsial classification scheme with the addition of a fourth lineage, transitional group (TRG rickettsiae, that is unique from TG and SFG rickettsiae and harbors genes from possible exchanges with AG rickettsiae via conjugation. We offer insight into the evolution of a plastic plasmid system in rickettsiae, including the role plasmids may have played in

  19. Importation of exotic ticks and tick-borne spotted fever group rickettsiae into the United States by migrating songbirds.

    Science.gov (United States)

    Mukherjee, Nabanita; Beati, Lorenza; Sellers, Michael; Burton, Laquita; Adamson, Steven; Robbins, Richard G; Moore, Frank; Karim, Shahid

    2014-03-01

    Birds are capable of carrying ticks and, consequently, tick-transmitted microorganisms over long distances and across geographical barriers such as oceans and deserts. Ticks are hosts for several species of spotted fever group rickettsiae (SFGR), which can be transmitted to vertebrates during blood meals. In this study, the prevalence of this group of rickettsiae was examined in ticks infesting migratory songbirds by using polymerase chain reaction (PCR). During the 2009 and 2010 spring migration season, 2064 northward-migrating passerine songbirds were examined for ticks at Johnson Bayou, Louisiana. A total of 91 ticks was removed from 35 individual songbirds for tick species identification and spotted fever group rickettsia detection. Ticks were identified as Haemaphysalis juxtakochi (n=38, 42%), Amblyomma longirostre (n=22, 24%), Amblyomma nodosum (n=17, 19%), Amblyomma calcaratum (n=11, 12%), Amblyomma maculatum (n=2, 2%), and Haemaphysalis leporispalustris (n=1, 1%) by comparing their 12S rDNA gene sequence to homologous sequences in GenBank. Most of the identified ticks were exotic species originating outside of the United States. The phylogenetic analysis of the 71 ompA gene sequences of the rickettsial strains detected in the ticks revealed the occurrence of 6 distinct rickettsial genotypes. Two genotypes (corresponding to a total of 28 samples) were included in the Candidatus Rickettsia amblyommii clade (less than 1% divergence), 2 of them (corresponding to a total of 14 samples) clustered with Rickettsia sp. "Argentina" with less than 0.2% sequence divergence, and 2 of them (corresponding to a total of 27 samples), although closely related to the R. parkeri-R. africae lineage (2.50-3.41% divergence), exhibited sufficient genetic divergence from its members to possibly constitute a new rickettsial genotype. Overall, there does not seem to be a specific relationship between exotic tick species, the rickettsiae they harbor, or the reservoir competence of the

  20. Detecting Rickettsia parkeri infection from eschar swab specimens.

    Science.gov (United States)

    Myers, Todd; Lalani, Tahaniyat; Dent, Mike; Jiang, Ju; Daly, Patrick L; Maguire, Jason D; Richards, Allen L

    2013-05-01

    The typical clinical presentation of several spotted fever group Rickettsia infections includes eschars. Clinical diagnosis of the condition is usually made by analysis of blood samples. We describe a more sensitive, noninvasive means of obtaining a sample for diagnosis by using an eschar swab specimen from patients infected with Rickettsia parkeri.

  1. Molecular detection of Rickettsia species in Amblyomma ticks collected from snakes in Thailand.

    Science.gov (United States)

    Sumrandee, Chalao; Hirunkanokpun, Supanee; Doornbos, Kathryn; Kitthawee, Sangvorn; Baimai, Visut; Grubhoffer, Libor; Trinachartvanit, Wachareeporn; Ahantarig, Arunee

    2014-10-01

    Some reptile ticks are potential vectors of pathogens such as spotted fever group (SFG) rickettsiae. Here, we report for the first time in detail the molecular evidence, DNA sequences and phylogenetic studies, for the presence of Rickettsia spp. in Amblyomma ticks (Amblyomma helvolum and Amblyomma varanense) from snakes in Thailand. A total of 24 tick samples was collected from 4 snake species and identified. A phylogenetic analysis inferred from the partial sequences of the gltA gene indicated that the Rickettsia spp. from 2 Amblyomma helvolum and 1 Amblyomma varanense belong to the same group as the SFG rickettsiae, which are closely related to Rickettsia raoultii strains. In contrast, there was 1 Rickettsia sp. from Amblyomma helvolum grouped into the same clade with other SFG rickettsiae (Rickettsia tamurae, Rickettsia monacensis, and a Rickettsia endosymbiont of Amblyomma dubitatum from Brazil). However, another Rickettsia sp. from Amblyomma varanense was closely related to Rickettsia bellii and Rickettsia sp. strain RDa420 from Thailand. In addition, from phylogenetic results based on the 16S rRNA gene and a concatenated tree of the 3 genes (gltA, ompA, and ompB), we found what may be a novel SFG rickettsia species closely related to Rickettsia raoultii (from both Amblyomma varanense and Amblyomma helvolum). In conclusion, our findings are the first report on the presence of novel SFG rickettsiae in 2 snake tick species, Amblyomma varanense and Amblyomma helvolum in Thailand and in south-eastern Asia.

  2. Exotic Rickettsiae in Ixodes ricinus: fact or artifact?

    Directory of Open Access Journals (Sweden)

    Reimerink Johan HJ

    2010-06-01

    Full Text Available Abstract Several pathogenic Rickettsia species can be transmitted via Ixodes ricinus ticks to humans and animals. Surveys of I. ricinus for the presence of Rickettsiae using part of its 16S rRNA gene yield a plethora of new and different Rickettsia sequences. Interpreting these data is sometimes difficult and presenting these findings as new or potentially pathogenic Rickettsiae should be done with caution: a recent report suggested presence of a known human pathogen, R. australis, in questing I. ricinus ticks in Europe. A refined analysis of these results revealed that R. helvetica was most likely to be misinterpreted as R. australis. Evidence in the literature is accumulating that rickettsial DNA sequences found in tick lysates can also be derived from other sources than viable, pathogenic Rickettsiae. For example, from endosymbionts, environmental contamination or even horizontal gene transfer.

  3. Differences in Intracellular Fate of Two Spotted Fever Group Rickettsia in Macrophage-Like Cells

    OpenAIRE

    Pedro Curto; Isaura Simoes; Riley, Sean P; Juan Jose Martinez

    2016-01-01

    Spotted fever group (SFG) rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (Rickettsia conorii) and Rocky Mountain spotted fever (Rickettsia rickettsii). Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickett...

  4. Molecular detection of Rickettsia bellii and Rickettsia sp. strain Colombianensi in ticks from Cordoba, Colombia.

    Science.gov (United States)

    Miranda, Jorge; Mattar, Salim

    2014-03-01

    The purpose of this study was to provide molecular evidence of Rickettsia spp. in ticks collected from 2 sites of Cordoba. From May to June 2009, 1069 Amblyomma cajennense ticks were removed from 40 capybaras (Hydrochoerus hydrochaeris) in a rural locality of Monteria. Furthermore, 458 Amblyomma sp. larvae and 20 Amblyomma sp. nymphs were collected in a rural locality of Los Cordobas (Cordoba) by drag sampling on vegetation (n=1547). Ticks were grouped into pools and tested for rickettsial infection by real-time PCR targeting the rickettsial gene gltA. Subsequently, PCR targeting for gltA, ompA, ompB, and 16S rRNA, sequencing, and phylogenetic analyses were undertaken. Rickettsial DNA was detected in 10 (4.6%) out of 214 pools of ticks by RT-PCR. Five (33%) of free-living Amblyomma sp. larval pools were positive, as well as 5 (2.6%) pools from A. cajennense. Only the gltA gene was amplified from 5 pools of free-living larvae. The nucleotide sequences were 100% identical to R. bellii by BLAST. Only one pool from A. cajennense was positive for gltA, ompA, ompB, and 16S rRNA. The partial nucleotide sequences of these genes were 100% identical to nucleotide sequences of the same genes of a new proposed species Candidatus Rickettsia sp. strain Colombianensi. This is the first report of R. bellii in ticks in Colombia and the second report of detection of Candidatus Rickettsia sp. strain Colombianensi. These Rickettsia species are still considered of unknown pathogenicity. Further studies are needed to characterize the ecological and potential pathogenic role of these 2 Rickettsia species found in Cordoba.

  5. Carrying Capacity

    DEFF Research Database (Denmark)

    Schroll, Henning; Andersen, Jan; Kjærgård, Bente

    2012-01-01

    A spatial planning act was introduced inIndonesia 1992 and renewed in 2008. It emphasised the planning role of decentralised authorities. The spatial planning act covers both spatial and environmental issues. It defines the concept of carrying capacity and includes definitions of supportive...... carrying capacity (SCC) and assimilative carrying capacity (ACC). The act mandates that the latter two aspects must be taken into consideration in the local spatial plans. The present study aimed at developing a background for a national guideline for carrying capacity in Indonesian provinces and districts...... standard or governmental political objective exists. In most cases it was possible to select a set of indicators, including thresholds that are workable in a carrying capacity planning at the local administrative levels. Not all relevant sectors at the decentralized level were included. Indicators of SCC...

  6. Tick-borne rickettsiae in Guinea and Liberia.

    Science.gov (United States)

    Mediannikov, Oleg; Diatta, Georges; Zolia, Yah; Balde, Mamadou Cellou; Kohar, Henry; Trape, Jean-François; Raoult, Didier

    2012-02-01

    While the high seroprevalence for the rickettsiae that cause spotted fevers and the multiple pathogenic rickettsiae is known, the data on the distribution of rickettsial diseases in Africa are often incomplete. We collected ticks from domestic or wild animals (generally a source of bushmeat) that were in contact with humans in 2 neighboring countries of tropical West Africa, Guinea and Liberia. In total, 382 ticks representing 6 species were collected in Liberia and 655 ticks representing 7 species were collected in Guinea. We found rickettsiae in 9 different species of ticks from both countries. Rickettsia africae was found in 93-100% of Amblyomma variegatum, in 14-93% of Rhipicephalus (B.) geigyi, Rh. (B.) annulatus, and Rh. (B.) decoloratus, and in several Hyalomma marginatum rufipes and Haemaphysalis paraleachi. A genetic variant of R. africae was found in Amblyomma compressum. R. massiliae was found in 10/61 (16%) of Rh. senegalensis ticks and in 2% of Haemaphysalis paraleachi ticks collected from dogs. We identified a new rickettsia in one of 44 (2%) Ixodes muniensis collected from a dog in Liberia. As this rickettsia is not yet isolated, we propose the provisional name "Candidatus Rickettsia liberiensis" (for the West African country where the host tick was collected).

  7. The natural infection of birds and ticks feeding on birds with Rickettsia spp. and Coxiella burnetii in Slovakia.

    Science.gov (United States)

    Berthová, Lenka; Slobodník, Vladimír; Slobodník, Roman; Olekšák, Milan; Sekeyová, Zuzana; Svitálková, Zuzana; Kazimírová, Mária; Špitalská, Eva

    2016-03-01

    Ixodid ticks (Acari: Ixodidae) are known as primary vectors of many pathogens causing diseases in humans and animals. Ixodes ricinus is a common ectoparasite in Europe and birds are often hosts of subadult stages of the tick. From 2012 to 2013, 347 birds belonging to 43 species were caught and examined for ticks in three sites of Slovakia. Ticks and blood samples from birds were analysed individually for the presence of Rickettsia spp. and Coxiella burnetii by PCR-based methods. Only I. ricinus was found to infest birds. In total 594 specimens of bird-attached ticks were collected (451 larvae, 142 nymphs, 1 female). Altogether 37.2% (16/43) of bird species were infested by ticks and some birds carried more than one tick. The great tit, Parus major (83.8%, 31/37) was the most infested species. In total, 6.6 and 2.7% of bird-attached ticks were infected with Rickettsia spp. and C. burnetii, respectively. Rickettsia helvetica predominated (5.9%), whereas R. monacensis (0.5%) was only sporadically detected. Coxiella burnetii was detected in 0.9%, Rickettsia spp. in 8.9% and R. helvetica in 4.2% of bird blood samples. The great tit was the bird species most infested with I. ricinus, carried R. helvetica and C. burnetti positive tick larvae and nymphs and was found to be rickettsaemic in its blood. Further studies are necessary to define the role of birds in the circulation of rickettsiae and C. burnetii in natural foci.

  8. Candidatus ‘Rickettsia senegalensis’ in cat fleas in Senegal

    Directory of Open Access Journals (Sweden)

    O. Mediannikov

    2015-01-01

    Full Text Available Epidemiological studies of Rickettsia felis and related bacteria are very important, because the natural cycle of this important infection has not yet been established. The recent emergence of R. felis-associated febrile diseases in West and East Africa demands insightful epidemiological studies of the vectors and reservoirs of this bacterium in Africa. Twenty-nine cat fleas, Ctenocephalides felis, were tested for the presence of rickettsiae, including R. felis, bartonellae, and borreliae, with specific quantitative real-time PCR assays. Supporting our previous studies, R. felis was not detected in the fleas collected. In addition, neither Bartonella nor Borrelia was found. In five (17% examined fleas, we found another species of rickettsia. We isolated three rickettsial strains, and genetic analysis demonstrated that these strains represent a probable new species, provisionally called Candidatus Rickettsia senegalensis here.

  9. Rickettsia felis in Ctenocephalides felis from Guatemala and Costa Rica

    Science.gov (United States)

    Troyo, Adriana; Álvarez, Danilo; Taylor, Lizeth; Abdalla, Gabriela; Calderón-Arguedas, Ólger; Zambrano, Maria L.; Dasch, Gregory A.; Lindblade, Kim; Hun, Laya; Eremeeva, Marina E.; Estévez, Alejandra

    2012-01-01

    Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal2 in samples from both countries, and genotype Rf2125 in Costa Rica. This is the first report of R. felis in Guatemala and of genotype Rf2125 in Costa Rica. The extensive presence of this pathogen in countries of Central America stresses the need for increased awareness and diagnosis. PMID:22665618

  10. Genetic identification of rickettsiae isolated from ticks in Japan.

    Science.gov (United States)

    Fournier, Pierre-Edouard; Fujita, Hiromi; Takada, Nobuhiro; Raoult, Didier

    2002-06-01

    Following the description in Japan of Japanese spotted fever, caused by Rickettsia japonica, a search for the vector of this disease led to the isolation of several rickettsiae from various tick species. Sixty-three rickettsial isolates were obtained from six different tick species, and six type strains were described by PCR and monoclonal antibody testing. We identified these six strains by amplification and sequencing of the genes encoding 16S rRNA and citrate synthase. We confirmed that the isolates from Dermacentor taiwanensis and Haemaphysalis flava ticks were R. japonica isolates. In Ixodes ovatus, Ixodes persulcatus, and Ixodes monospinosus, we identified a Rickettsia identical or closely related to Rickettsia helvetica, a species that is pathogenic for humans and that to date has only been found in Europe. Finally, we identified a new genotype of unknown pathogenicity, genotype AT, that was isolated from Amblyomma testudinarium ticks and that is closely related to a Slovakian genotype obtained from Ixodes ricinus ticks.

  11. Zoonotic surveillance for rickettsiae in domestic animals in Kenya.

    Science.gov (United States)

    Mutai, Beth K; Wainaina, James M; Magiri, Charles G; Nganga, Joseph K; Ithondeka, Peter M; Njagi, Obadiah N; Jiang, Ju; Richards, Allen L; Waitumbi, John N

    2013-06-01

    Abstract Rickettsiae are obligate intracellular bacteria that cause zoonotic and human diseases. Arthropod vectors, such as fleas, mites, ticks, and lice, transmit rickettsiae to vertebrates during blood meals. In humans, the disease can be life threatening. This study was conducted amidst rising reports of rickettsioses among travelers to Kenya. Ticks and whole blood were collected from domestic animals presented for slaughter at major slaughterhouses in Nairobi and Mombasa that receive animals from nearly all counties in the country. Blood samples and ticks were collected from 1019 cattle, 379 goats, and 299 sheep and were screened for rickettsiae by a quantitative PCR (qPCR) assay (Rick17b) using primers and probe that target the genus-specific 17-kD gene (htrA). The ticks were identified using standard taxonomic keys. All Rick17b-positive tick DNA samples were amplified and sequenced with primers sets that target rickettsial outer membrane protein genes (ompA and ompB) and the citrate-synthase encoding gene (gltA). Using the Rick17b qPCR, rickettsial infections in domestic animals were found in 25/32 counties sampled (78.1% prevalence). Infection rates were comparable in cattle (16.3%) and sheep (15.1%) but were lower in goats (7.1%). Of the 596 ticks collected, 139 had rickettsiae (23.3%), and the detection rates were highest in Amblyomma (62.3%; n=104), then Rhipicephalus (45.5%; n=120), Hyalomma (35.9%; n=28), and Boophilus (34.9%; n=30). Following sequencing, 104 out of the 139 Rick17b-positive tick DNA had good reverse and forward sequences for the 3 target genes. On querying GenBank with the generated consensus sequences, homologies of 92-100% for the following spotted fever group (SFG) rickettsiae were identified: Rickettsia africae (93.%, n=97), Rickettsia aeschlimannii (1.9%, n=2), Rickettsia mongolotimonae (0.96%, n=1), Rickettsia conorii subsp. israelensis (0.96%, n=1), Candidatus Rickettsia kulagini (0.96% n=1), and Rickettsia spp. (1.9% n=2). In

  12. Tick-borne rickettsiae in Guinea and Liberia

    OpenAIRE

    Mediannikov, Oleg; Diatta, G.; Zolia, Y.; Balde, M. C.; Kohar, H.; Trape, Jean-François; Raoult, Didier

    2012-01-01

    While the high seroprevalence for the rickettsiae that cause spotted fevers and the multiple pathogenic rickettsiae is known, the data on the distribution of rickettsial diseases in Africa are often incomplete. We collected ticks from domestic or wild animals (generally a source of bushmeat) that were in contact with humans in 2 neighboring countries of tropical West Africa, Guinea and Liberia. In total, 382 ticks representing 6 species were collected in Liberia and 655 ticks representing 7 s...

  13. Detection of Rickettsia in Rhipicephalus sanguineus ticks and Ctenocephalides felis fleas from southeastern Tunisia by reverse line blot assay.

    Science.gov (United States)

    Khrouf, Fatma; M'Ghirbi, Youmna; Znazen, Abir; Ben Jemaa, Mounir; Hammami, Adnene; Bouattour, Ali

    2014-01-01

    Ticks (n = 663) and fleas (n = 470) collected from domestic animals from southeastern Tunisia were screened for Rickettsia infection using reverse line blot assay. Evidence of spotted fever group Rickettsia was obtained. We detected Rickettsia felis in fleas, Rickettsia massiliae Bar 29 and the Rickettsia conorii Israeli spotted fever strain in ticks, and Rickettsia conorii subsp. conorii and Rickettsia spp. in both arthropods. The sensitivity of the adopted technique allowed the identification of a new association between fleas and R. conorii subsp. conorii species. The presence of these vector-borne Rickettsia infections should be considered when diagnosing this disease in humans in Tunisia.

  14. Rickettsia species in fleas collected from small mammals in Slovakia.

    Science.gov (United States)

    Špitalská, Eva; Boldiš, Vojtech; Mošanský, Ladislav; Sparagano, Olivier; Stanko, Michal

    2015-11-01

    Epidemiological and epizootiological studies of Rickettsia felis and other Rickettsia spp. are very important, because their natural cycle has not yet been established completely. In total, 315 fleas (Siphonaptera) of 11 species of Ceratophyllidae, Hystrichopsyllidae and Leptopsyllidae families were tested for the presence of Rickettsia species and Coxiella burnetii with conventional and specific quantitative real-time PCR assays. Fleas were collected from five rodent hosts (Myodes glareolus, Apodemus flavicollis, Apodemus agrarius, Microtus subterraneus, Microtus arvalis) and three shrew species (Sorex araneus, Neomys fodiens, Crocidura suaveolens) captured in Eastern and Southern Slovakia. Overall, Rickettsia spp. was found in 10.8% (34/315) of the tested fleas of Ctenophthalmus agyrtes, Ctenophthalmus solutus, Ctenophthalmus uncinatus and Nosopsyllus fasciatus species. Infected fleas were coming from A. flavicollis, A. agrarius, and M. glareolus captured in Eastern Slovakia. C. burnetii was not found in any fleas. R. felis, Rickettsia helvetica, unidentified Rickettsia, and rickettsial endosymbionts were identified in fleas infesting small mammals in the Košice region, Eastern Slovakia. This study is the first report of R. felis infection in C. solutus male flea collected from A. agrarius in Slovakia.

  15. Dynamics of the endosymbiont Rickettsia in an insect pest.

    Science.gov (United States)

    Cass, Bodil N; Yallouz, Rachel; Bondy, Elizabeth C; Mozes-Daube, Netta; Horowitz, A Rami; Kelly, Suzanne E; Zchori-Fein, Einat; Hunter, Martha S

    2015-07-01

    A new heritable bacterial association can bring a fresh set of molecular capabilities, providing an insect host with an almost instantaneous genome extension. Increasingly acknowledged as agents of rapid evolution, inherited microbes remain underappreciated players in pest management programs. A Rickettsia bacterium was tracked sweeping through populations of an invasive whitefly provisionally described as the "B" or "MEAM1" of the Bemisia tabaci species complex, in the southwestern USA. In this population, Rickettsia provides strong fitness benefits and distorts whitefly sex ratios under laboratory conditions. In contrast, whiteflies in Israel show few apparent fitness benefits from Rickettsia under laboratory conditions, only slightly decreasing development time. A survey of B. tabaci B samples revealed the distribution of Rickettsia across the cotton-growing regions of Israel and the USA. Thirteen sites from Israel and 22 sites from the USA were sampled. Across the USA, Rickettsia frequencies were heterogeneous among regions, but were generally very high, whereas in Israel, the infection rates were lower and declining. The distinct outcomes of Rickettsia infection in these two countries conform to previously reported phenotypic differences. Intermediate frequencies in some areas in both countries may indicate a cost to infection in certain environments or that the frequencies are in flux. This suggests underlying geographic differences in the interactions between bacterial symbionts and this serious agricultural pest.

  16. Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan

    OpenAIRE

    Masako Andoh; Akiko Sakata; Ai Takano; Hiroki Kawabata; Hiromi Fujita; Yumi Une; Koichi Goka; Toshio Kishimoto; Shuji Ando

    2015-01-01

    One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the pre...

  17. Genetic variability of Rickettsia spp. in Ixodes persulcatus/Ixodes trianguliceps sympatric areas from Western Siberia, Russia: Identification of a new Candidatus Rickettsia species.

    Science.gov (United States)

    Igolkina, Yana P; Rar, Vera A; Yakimenko, Valeriy V; Malkova, Marina G; Tancev, Aleksey K; Tikunov, Artem Yu; Epikhina, Tamara I; Tikunova, Nina V

    2015-08-01

    Rickettsia spp. are the causative agents of a number of diseases in humans. These bacteria are transmitted by arthropods, including ixodid ticks. DNA of several Rickettsia spp. was identified in Ixodes persulcatus ticks, however, the association of Ixodes trianguliceps ticks with Rickettsia spp. is unknown. In our study, blood samples of small mammals (n=108), unfed adult I. persulcatus ticks (n=136), and I. persulcatus (n=12) and I. trianguliceps (n=34) ticks feeding on voles were collected in two I. persulcatus/I. trianguliceps sympatric areas in Western Siberia. Using nested PCR, ticks and blood samples were studied for the presence of Rickettsia spp. Three distinct Rickettsia species were found in ticks, but no Rickettsia species were found in the blood of examined voles. Candidatus Rickettsia tarasevichiae DNA was detected in 89.7% of unfed I. persulcatus, 91.7% of engorged I. persulcatus and 14.7% of I. trianguliceps ticks. Rickettsia helvetica DNA was detected in 5.9% of I. trianguliceps ticks. In addition, a new Rickettsia genetic variant was found in 32.4% of I. trianguliceps ticks. Sequence analysis of the 16S rRNA, gltA, ompA, оmpB and sca4 genes was performed and, in accordance with genetic criteria, a new Rickettsia genetic variant was classified as a new Candidatus Rickettsia species. We propose to name this species Candidatus Rickettsia uralica, according to the territory where this species was initially identified. Candidatus Rickettsia uralica was found to belong to the spotted fever group. The data obtained in this study leads us to propose that Candidatus Rickettsia uralica is associated with I. trianguliceps ticks.

  18. Development of shuttle vectors for transformation of diverse Rickettsia species.

    Directory of Open Access Journals (Sweden)

    Nicole Y Burkhardt

    Full Text Available Plasmids have been identified in most species of Rickettsia examined, with some species maintaining multiple different plasmids. Three distinct plasmids were demonstrated in Rickettsia amblyommii AaR/SC by Southern analysis using plasmid specific probes. Copy numbers of pRAM18, pRAM23 and pRAM32 per chromosome in AaR/SC were estimated by real-time PCR to be 2.0, 1.9 and 1.3 respectively. Cloning and sequencing of R. amblyommii AaR/SC plasmids provided an opportunity to develop shuttle vectors for transformation of rickettsiae. A selection cassette encoding rifampin resistance and a fluorescent marker was inserted into pRAM18 yielding a 27.6 kbp recombinant plasmid, pRAM18/Rif/GFPuv. Electroporation of Rickettsia parkeri and Rickettsia bellii with pRAM18/Rif/GFPuv yielded GFPuv-expressing rickettsiae within 2 weeks. Smaller vectors, pRAM18dRG, pRAM18dRGA and pRAM32dRGA each bearing the same selection cassette, were made by moving the parA and dnaA-like genes from pRAM18 or pRAM32 into a vector backbone. R. bellii maintained the highest numbers of pRAM18dRGA (13.3 - 28.1 copies, and R. parkeri, Rickettsia monacensis and Rickettsia montanensis contained 9.9, 5.5 and 7.5 copies respectively. The same species transformed with pRAM32dRGA maintained 2.6, 2.5, 3.2 and 3.6 copies. pRM, the plasmid native to R. monacensis, was still present in shuttle vector transformed R. monacensis at a level similar to that found in wild type R. monacensis after 15 subcultures. Stable transformation of diverse rickettsiae was achieved with a shuttle vector system based on R. amblyommii plasmids pRAM18 and pRAM32, providing a new research tool that will greatly facilitate genetic and biological studies of rickettsiae.

  19. Progress in the insect symbiont Rickettsia%昆虫共生细菌 Rickettsia 的研究进展

    Institute of Scientific and Technical Information of China (English)

    潘慧鹏; 张友军

    2012-01-01

    Rickettsia是传播和引起人类与其他脊椎动物疾病的胞内共生菌.引起脊椎动物疾病的这些Rickettsia,其部分生活史是在节肢动物体内完成的;而另外许多Rickettsia,其整个生活史都是在宿主节肢动物体内完成.为了叙述方便,把前者称为脊椎动物Rickettsia,后者称为节肢动物Rickettsia.过去的研究主要集中在医学上具有重大意义的脊椎动物Rickettsia,而关于节肢动物Rickettsia的生物学特性等研究则相对较少.近年来,研究者们加大了对昆虫Rickettsia的研究,发现昆虫Rickettsia广泛分布于昆虫中,且有两种存在形式.其可以通过垂直卵传的方式在世代间传递,也可以通过寄生蜂和寄主植物达到在昆虫之间传播的目的.昆虫Rickettsia可通过诱导孤雌生殖、诱导杀雄等方式影响宿主的生殖行为.其对不同宿主昆虫可产生对宿主有利或有害的作用;可增强宿主昆虫抵御高温和寄生蜂的能力,与宿主昆虫对药剂的敏感性相关.最后,昆虫Rickettsia具有一个简化的基因组,且存在进一步减小的可能性.%Rickettsia species are intracellular symbionts of eukaryotes that are well known for infecting and causing serious diseases in humans and other vertebrates. All known vertebrate associated Rickettsia bacteria are vectored by arthropods as part of their life-cycle, and many other Rickettsia species are found exclusively in arthropods without any secondary host. For convenience, we refer to the former as vertebrate Rickettsia and the latter as arthropod Rickettsia. Previous research efforts mainly focused on medically important vertebrate Rickettsia. The biological studies of arthropod Rickettsia were limited- In recent years, more efforts have been made on the insect symbiont Rickettsia and considerable achievements have been obtained. The insect symbiont Rickettsia is distributed among insects, and two different localization patterns exist in the same insect

  20. Rickettsia massiliae and Rickettsia conorii Israeli Spotted Fever Strain Differentially Regulate Endothelial Cell Responses.

    Science.gov (United States)

    Bechelli, Jeremy; Smalley, Claire; Milhano, Natacha; Walker, David H; Fang, Rong

    2015-01-01

    Rickettsiae primarily target microvascular endothelial cells. However, it remains elusive how endothelial cell responses to rickettsiae play a role in the pathogenesis of rickettsial diseases. In the present study, we employed two rickettsial species with high sequence homology but differing virulence to investigate the pathological endothelial cell responses. Rickettsia massiliae is a newly documented human pathogen that causes a mild spotted fever rickettsiosis. The "Israeli spotted fever" strain of R. conorii (ISF) causes severe disease with a mortality rate up to 30% in hospitalized patients. At 48 hours post infection (HPI), R. conorii (ISF) induced a significant elevation of IL-8 and IL-6 while R. massiliae induced a statistically significant elevated amount of MCP-1 at both transcriptional and protein synthesis levels. Strikingly, R. conorii (ISF), but not R. massiliae, caused a significant level of cell death or injury in HMEC-1 cells at 72 HPI, demonstrated by live-dead cell staining, annexin V staining and lactate dehydrogenase release. Monolayers of endothelial cells infected with R. conorii (ISF) showed a statistically significant decrease in electrical resistance across the monolayer compared to both R. massiliae-infected and uninfected cells at 72 HPI, suggesting increased endothelial permeability. Interestingly, pharmacological inhibitors of caspase-1 significantly reduced the release of lactate dehydrogenase by R. conorii (ISF)-infected HMEC-1 cells, which suggests the role of caspase-1 in mediating the death of endothelial cells. Taken together, our data illustrated that a distinct proinflammatory cytokine profile and endothelial dysfunction, as evidenced by endothelial cell death/injury and increased permeability, are associated with the severity of rickettsial diseases.

  1. A novel Rickettsia species detected in Vole Ticks (Ixodes angustus) from Western Canada.

    Science.gov (United States)

    Anstead, Clare A; Chilton, Neil B

    2013-12-01

    The genomic DNA of ixodid ticks from western Canada was tested by PCR for the presence of Rickettsia. No rickettsiae were detected in Ixodes sculptus, whereas 18% of the I. angustus and 42% of the Dermacentor andersoni organisms examined were PCR positive for Rickettsia. The rickettsiae from each tick species were characterized genetically using multiple genes. Rickettsiae within the D. andersoni organisms had sequences at four genes that matched those of R. peacockii. In contrast, the Rickettsia present within the larvae, nymphs, and adults of I. angustus had novel DNA sequences at four of the genes characterized compared to the sequences available from GenBank for all recognized species of Rickettsia and all other putative species within the genus. Phylogenetic analyses of the sequence data revealed that the rickettsiae in I. angustus do not belong to the spotted fever, transitional, or typhus groups of rickettsiae but are most closely related to "Candidatus Rickettsia kingi" and belong to a clade that also includes R. canadensis, "Candidatus Rickettsia tarasevichiae," and "Candidatus Rickettsia monteiroi."

  2. Molecular Evidence of Different Rickettsia Species in Villeta, Colombia.

    Science.gov (United States)

    Faccini-Martínez, Álvaro A; Ramírez-Hernández, Alejandro; Forero-Becerra, Elkin; Cortés-Vecino, Jesús A; Escandón, Patricia; Rodas, Juan D; Palomar, Ana M; Portillo, Aránzazu; Oteo, José A; Hidalgo, Marylin

    2016-02-01

    The aim of this work was to detect and identify Rickettsia species in ticks collected in rural areas of Villeta, Colombia. Tick specimens were collected from domestic animals and walls of houses in five rural villages of Villeta town and from humans in Naranjal village (same town). Moreover, a flea collected from the same area was also processed. DNA was extracted and tested by conventional, semi-nested, and nested PCR reactions targeting rickettsial genes. In the ticks collected from humans from Naranjal village, a nymph of Amblyomma cajennense sensu lato was amplified using primers for ompA and sequenced (100% identity with "Candidatus Rickettsia amblyommii"). Last, three amplicons from the Ctenocephalides felis flea, corresponding to gltA, ompB, and 16S rRNA genes, showed high identity with R. felis (98.5%, 97.3%, and 99.2%, respectively) and "Candidatus Rickettsia asemboensis" (99.7% and 100%, respectively). To our knowledge, these results correspond to the first molecular detection in Colombia of "Candidatus Rickettsia amblyommii" and "Ca. Rickettsia asemboensis" in fleas.

  3. Genotyping, evolution and epidemiological findings of Rickettsia species.

    Science.gov (United States)

    Merhej, Vicky; Angelakis, Emmanouil; Socolovschi, Cristina; Raoult, Didier

    2014-07-01

    Rickettsiae are obligate intracellular bacteria that can cause mild to life-threatening diseases, including epidemic typhus, one of the oldest pernicious diseases of mankind. Clinical awareness of rickettsial diseases and molecular diagnosis have shown that rickettsioses should be viewed as new emerging and reemerging diseases. Rickettsia has been shown to be a large genus with a worldwide distribution, a very diverse host range, including hosts that have no relationship with vertebrate. Genomic studies have demonstrated genome reduction due to gene loss associated with increased pathogenicity and horizontal DNA acquisition according to a sympatric mode of evolution in hosts that contain several organisms. This article presents a review of genotyping techniques and examines the principle of genotype determination in terms of taxonomic strategies and detection methods. This article summarizes the epidemiological and pathological features of Rickettsia and discusses the genomic findings that help the understanding of the evolution of pathogenicity including the deleterious mutations of repair systems and the toxin-antitoxin systems.

  4. Rickettsia conorii israelensis in Rhipicephalus sanguineus ticks, Sardinia, Italy.

    Science.gov (United States)

    Chisu, Valentina; Masala, Giovanna; Foxi, Cipriano; Socolovschi, Cristina; Raoult, Didier; Parola, Philippe

    2014-06-01

    The presence of tick-borne Rickettsia spp. was examined by PCR using DNA samples extracted from 254 ticks collected from mammals originating from northern and eastern Sardinia, Italy. The spotted fever group rickettsial agent Rickettsia conorii israelensis was detected in 3 Rhipicephalus sanguineus ticks from a dog for the first time in this geographical area. In addition, Ri. massiliae, Ri. slovaca, and Ri. aeschlimannii were detected in Rh. turanicus, Rh. sanguineus, Dermacentor marginatus, and Hyalomma marginatum marginatum ticks from dogs, goats, wild boar, and horse. Moreover, Candidatus Rickettsia barbariae was detected in 2 Rh. turanicus ticks from goats. The detection of Ri. conorii israelensis, an emergent agent which causes Israeli spotted fever, increases our knowledge on tick-borne rickettsioses in Sardinia.

  5. Molecular detection and characterization of spotted fever group rickettsiae in ticks from Central Italy.

    Science.gov (United States)

    Scarpulla, M; Barlozzari, G; Marcario, A; Salvato, L; Blanda, V; De Liberato, C; D'Agostini, C; Torina, A; Macrì, G

    2016-07-01

    The aim of this study was to investigate the presence of rickettsial pathogens in ticks from Central Italy. A total of 113 ticks hailed from Latium and Tuscany regions were identified and tested by PCR to detect gltA, ompA, ompB genes of Rickettsia. Positive amplicons were sequenced and identified at species level. Ticks were analyzed individually or in pools. The percentage of positivity for SFG rickettsiae was 12.4%, expressed as minimum infection rate (MIR) assuming that one tick was positive in each positive pool. Rickettsia aeschlimannii was detected in Hyalomma marginatum, Rickettsia monacensis in Ixodes ricinus and Rickettsia massiliae and Rickettsia conorii in Rhipicephalus sanguineus sensu lato. These findings confirm the circulation of pathogenic rickettsiae in Latium and Tuscany regions. To our knowledge this is the first report of R. massiliae in Latium region.

  6. Which Way In? The RalF Arf-GEF Orchestrates Rickettsia Host Cell Invasion.

    Directory of Open Access Journals (Sweden)

    Kristen E Rennoll-Bankert

    2015-08-01

    Full Text Available Bacterial Sec7-domain-containing proteins (RalF are known only from species of Legionella and Rickettsia, which have facultative and obligate intracellular lifestyles, respectively. L. pneumophila RalF, a type IV secretion system (T4SS effector, is a guanine nucleotide exchange factor (GEF of ADP-ribosylation factors (Arfs, activating and recruiting host Arf1 to the Legionella-containing vacuole. In contrast, previous in vitro studies showed R. prowazekii (Typhus Group RalF is a functional Arf-GEF that localizes to the host plasma membrane and interacts with the actin cytoskeleton via a unique C-terminal domain. As RalF is differentially encoded across Rickettsia species (e.g., pseudogenized in all Spotted Fever Group species, it may function in lineage-specific biology and pathogenicity. Herein, we demonstrate RalF of R. typhi (Typhus Group interacts with the Rickettsia T4SS coupling protein (RvhD4 via its proximal C-terminal sequence. RalF is expressed early during infection, with its inactivation via antibody blocking significantly reducing R. typhi host cell invasion. For R. typhi and R. felis (Transitional Group, RalF ectopic expression revealed subcellular localization with the host plasma membrane and actin cytoskeleton. Remarkably, R. bellii (Ancestral Group RalF showed perinuclear localization reminiscent of ectopically expressed Legionella RalF, for which it shares several structural features. For R. typhi, RalF co-localization with Arf6 and PI(4,5P2 at entry foci on the host plasma membrane was determined to be critical for invasion. Thus, we propose recruitment of PI(4,5P2 at entry foci, mediated by RalF activation of Arf6, initiates actin remodeling and ultimately facilitates bacterial invasion. Collectively, our characterization of RalF as an invasin suggests that, despite carrying a similar Arf-GEF unknown from other bacteria, different intracellular lifestyles across Rickettsia and Legionella species have driven divergent roles

  7. Which Way In? The RalF Arf-GEF Orchestrates Rickettsia Host Cell Invasion.

    Science.gov (United States)

    Rennoll-Bankert, Kristen E; Rahman, M Sayeedur; Gillespie, Joseph J; Guillotte, Mark L; Kaur, Simran J; Lehman, Stephanie S; Beier-Sexton, Magda; Azad, Abdu F

    2015-08-01

    Bacterial Sec7-domain-containing proteins (RalF) are known only from species of Legionella and Rickettsia, which have facultative and obligate intracellular lifestyles, respectively. L. pneumophila RalF, a type IV secretion system (T4SS) effector, is a guanine nucleotide exchange factor (GEF) of ADP-ribosylation factors (Arfs), activating and recruiting host Arf1 to the Legionella-containing vacuole. In contrast, previous in vitro studies showed R. prowazekii (Typhus Group) RalF is a functional Arf-GEF that localizes to the host plasma membrane and interacts with the actin cytoskeleton via a unique C-terminal domain. As RalF is differentially encoded across Rickettsia species (e.g., pseudogenized in all Spotted Fever Group species), it may function in lineage-specific biology and pathogenicity. Herein, we demonstrate RalF of R. typhi (Typhus Group) interacts with the Rickettsia T4SS coupling protein (RvhD4) via its proximal C-terminal sequence. RalF is expressed early during infection, with its inactivation via antibody blocking significantly reducing R. typhi host cell invasion. For R. typhi and R. felis (Transitional Group), RalF ectopic expression revealed subcellular localization with the host plasma membrane and actin cytoskeleton. Remarkably, R. bellii (Ancestral Group) RalF showed perinuclear localization reminiscent of ectopically expressed Legionella RalF, for which it shares several structural features. For R. typhi, RalF co-localization with Arf6 and PI(4,5)P2 at entry foci on the host plasma membrane was determined to be critical for invasion. Thus, we propose recruitment of PI(4,5)P2 at entry foci, mediated by RalF activation of Arf6, initiates actin remodeling and ultimately facilitates bacterial invasion. Collectively, our characterization of RalF as an invasin suggests that, despite carrying a similar Arf-GEF unknown from other bacteria, different intracellular lifestyles across Rickettsia and Legionella species have driven divergent roles for Ral

  8. Intraocular inflammation as the main manifestation of Rickettsia conorii infection

    Directory of Open Access Journals (Sweden)

    Orduña A

    2011-09-01

    Full Text Available Archimedes LD Agahan1,3, Jenice Torres1, Graciana Fuentes-Páez1, Hernan Martínez-Osorio1, Antonio Orduña2, Margarita Calonge11Ocular Immunology and Uveitis Unit, Institute of Applied Ophthalmobiology (IOBA, 2Microbiology Department, University of Valladolid, Valladolid, Spain; 3Department of Ophthalmology and Visual Sciences, University of the Philippines, Philippine General Hospital, Manila, PhilippinesObjective: To report the clinical features and management of seven cases of intraocular inflammation caused by Rickettsia infection and review published literature.Methods: Rickettsia conorii or Rickettsia spp. infection was diagnosed based on the following criteria: (1 positive serology according to the European Guidelines, (2 titer normalization after specific treatment, and (3 complete resolution of ophthalmic disease and accompanying symptoms after antibiotic therapy.Results: Seven patients were referred for uveitis of unknown etiology. All came from regions where Mediterranean spotted fever is prevalent. One patient met the European guidelines criteria for Rickettsia spp. infection, while the other six cases met the criteria for R. conorii infection. The main symptoms were visual loss, floaters, eye redness, photophobia, and ocular pain. Predominant ophthalmic signs included vasculitis, choroiditis, vitritis, and macular edema. All patients required antibiotic treatment that resulted in the remission of the infection. Doxycycline was the first choice and the only antibiotic used to treat four patients. One patient needed ciprofloxacin as a second antibiotic after not responding to doxycycline. Two patients had doxycycline as a second antibiotic after not responding primarily to sulfonamides (which had been given after 2–3 days of doxycycline gastric intolerance; one of these patients needed ciprofloxacin as a third antibiotic.Conclusion: Intraocular inflammation can occur as the main manifestation of Rickettsia conorii or Rickettsia spp

  9. Isolation of a Spotted Fever Group Rickettsia, Rickettsia peacockii, in a Rocky Mountain Wood Tick, Dermacentor andersoni, Cell Line

    OpenAIRE

    Simser, Jason A.; Palmer, Ann T.; Munderloh, Ulrike G.; Kurtti, Timothy J.

    2001-01-01

    An embryonic cell line (DAE100) of the Rocky Mountain wood tick, Dermacentor andersoni, was observed by microscopy to be chronically infected with a rickettsialike organism. The organism was identified as a spotted fever group (SFG) rickettsia by PCR amplification and sequencing of portions of the 16S rRNA, citrate synthase, Rickettsia genus-specific 17-kDa antigen, and SFG-specific 190-kDa outer membrane protein A (rOmpA) genes. Sequence analysis of a partial rompA gene PCR fragment and indi...

  10. Small Regulatory RNAs of Rickettsia conorii

    Science.gov (United States)

    Narra, Hema P.; Schroeder, Casey L. C.; Sahni, Abha; Rojas, Mark; Khanipov, Kamil; Fofanov, Yuriy; Sahni, Sanjeev K.

    2016-01-01

    Small regulatory RNAs comprise critically important modulators of gene expression in bacteria, yet very little is known about their prevalence and functions in Rickettsia species. R. conorii, the causative agent of Mediterranean spotted fever, is a tick-borne pathogen that primarily infects microvascular endothelium in humans. We have determined the transcriptional landscape of R. conorii during infection of Human Microvascular Endothelial Cells (HMECs) by strand-specific RNA sequencing to identify 4 riboswitches, 13 trans-acting (intergenic), and 22 cis-acting (antisense) small RNAs (termed ‘Rc_sR’s). Independent expression of four novel trans-acting sRNAs (Rc_sR31, Rc_sR33, Rc_sR35, and Rc_sR42) and known bacterial sRNAs (6S, RNaseP_bact_a, ffs, and α-tmRNA) was next confirmed by Northern hybridization. Comparative analysis during infection of HMECs vis-à-vis tick AAE2 cells revealed significantly higher expression of Rc_sR35 and Rc_sR42 in HMECs, whereas Rc_sR31 and Rc_sR33 were expressed at similar levels in both cell types. We further predicted a total of 502 genes involved in all important biological processes as potential targets of Rc_sRs and validated the interaction of Rc_sR42 with cydA (cytochrome d ubiquinol oxidase subunit I). Our findings constitute the first evidence of the existence of post-transcriptional riboregulatory mechanisms in R. conorii and interactions between a novel Rc_sR and its target mRNA. PMID:27834404

  11. Cat fleas (Ctenocephalides felis) from cats and dogs in New Zealand: Molecular characterisation, presence of Rickettsia felis and Bartonella clarridgeiae and comparison with Australia.

    Science.gov (United States)

    Chandra, Shona; Forsyth, Maureen; Lawrence, Andrea L; Emery, David; Šlapeta, Jan

    2017-01-30

    The cat flea (Ctenocephalides felis) is the most common flea species parasitising both domestic cats and dogs globally. Fleas are known vectors of zoonotic pathogens such as vector borne Rickettsia and Bartonella. This study compared cat fleas from domestic cats and dogs in New Zealand's North and South Islands to Australian cat fleas, using the mitochondrial DNA (mtDNA) marker, cytochrome c oxidase subunit I and II (cox1, cox2). We assessed the prevalence of Rickettsia and Bartonella using genus specific multiplexed real-time PCR assays. Morphological identification confirmed that the cat flea (C. felis) is the most common flea in New Zealand. The examined fleas (n=43) at cox1 locus revealed six closely related C. felis haplotypes (inter-haplotype distance 1.1%) across New Zealand. The New Zealand C. felis haplotypes were identical or near identical with haplotypes from southern Australia demonstrating common dispersal of haplotype lineage across both the geographical (Tasman Sea) and climate scale. New Zealand cat fleas carried Rickettsia felis (5.3%) and Bartonella clarridgeiae (18.4%). To understand the capability of C. felis to vector zoonotic pathogens, we determined flea cox1 and cox2 haplotype diversity with the tandem multiplexed real-time PCR and sequencing for Bartonella and Rickettsia. This enabled us to demonstrate highly similar cat fleas on cat and dog populations across Australia and New Zealand.

  12. Coinfection with "Rickettsia sibirica subsp. mongolotimonae" and Rickettsia conorii in a Human Patient: a Challenge for Molecular Diagnosis Tools.

    Science.gov (United States)

    Nogueras, María Mercedes; Roson, Beatriz; Lario, Sergio; Sanfeliu, Isabel; Pons, Immaculada; Anton, Esperança; Casanovas, Aurora; Segura, Ferran

    2015-09-01

    Rickettsioses are zoonoses transmitted by vectors. More than one agent can coexist in vectors. Although vectors may transmit more than one microorganism to humans, information on dual infections is scarce. We present a case of a patient with an atypical rickettsiosis diagnosis in whom two species of Rickettsia were detected.

  13. Seroprevalence of Rickettsia spp. in Equids and Molecular Detection of 'Candidatus Rickettsia amblyommii' in Amblyomma cajennense Sensu Lato Ticks From the Pantanal Region of Mato Grosso, Brazil.

    Science.gov (United States)

    Alves, Alvair Da S; Melo, Andréia L T; Amorim, Marcus V; Borges, Alice M C M; Gaíva E Silva, Lucas; Martins, Thiago F; Labruna, Marcelo B; Aguiar, Daniel M; Pacheco, Richard C

    2014-11-01

    The aim of the study was to evaluate exposure of equids to rickettsial agents (Rickettsia rickettsii, Rickettsia parkeri, 'Candidatus Rickettsia amblyommii', Rickettsia rhipicephali, and Rickettsia bellii) and rickettsial infection in ticks of a Pantanal region of Brazil. Sera of 547 equids (500 horses and 47 donkeys) were evaluated by indirect immunofluorescence assay. In total, 665 adults and 106 nymphal pools of Amblyomma cajennense F. sensu lato, 10 Dermacentor nitens Neumann ticks, and 88 larval pools of Amblyomma sp. were tested by polymerase chain reaction (PCR). Overall, 337 (61.6%) equids were reactive (titer ≥64) to at least one antigen of Rickettsia spp. The prevalence values for Rickettsia were 66%, and the highest endpoint titers were observed for 'Ca. R. amblyommii'. By PCR 3 (0.45%) A. cajennense s.l. females were positive for 'Ca. R. amblyommii'. Minimum infection rates of 0.75% for nymphs and 0.34% for larvae were calculated. Positive samples of ticks have had a fragment of the 16S mitochondrial rRNA gene sequenced and sequences showed 99% identity to Amblyomma sculptum Berlese. This study reports a wide exposure of equids to Rickettsia agents, and PCR evidence of infection with 'Ca. R. amblyommii', for the first time, in A. sculptum.

  14. DETECTION OF RICKETTSIA FELIS LIKE AGENT FROM EULAELAPS STABULARIS KOCH%从厩真厉螨中检出与猫立克次体近缘的立克次体核酸片段

    Institute of Scientific and Technical Information of China (English)

    姚李四; 刘勇先; 邵丽筠; 张晓龙; 杨宇; 王静; 徐宝梁; 王宝麟; 赵彤言

    2012-01-01

    本研究用立克次体属特异的gltA和ompB基因扩增引物,从吉林长白县捕获鼠中分拣的534只厩真厉螨中扩得gltA和ompB基因片段.通过基因片段的序列测定、BLAST比对和系统发育分析,显示两个扩增基因与猫立克次体Rickettsia felis同源性最高(99%),证明该地区厩真厉螨携带与猫立克次体近缘的立克次体.%The segments of glt A gene and omp B gene were amplified and identified with Rickettsia specific git A and omp B primers from 534 mites (Eulaelaps stabularis Koch) collected from rodents of Changbai County, Jilin Province, China. By sequencing, BLAST qualifying and phylogenetic analyzing, it was revealed that the two amplified segments were of highest homology to Rickettsia fells (99% ) , implying that the locally collected E. Stabularis may carry some Rickettsia sp. Allied to Rickettsia fells.

  15. High prevalence of spotted fever group rickettsiae in Amblyomma variegatum from Uganda and their identification using sizes of intergenic spacers.

    Science.gov (United States)

    Nakao, Ryo; Qiu, Yongjin; Igarashi, Manabu; Magona, Joseph W; Zhou, Lijia; Ito, Kimihito; Sugimoto, Chihiro

    2013-12-01

    The spotted fever group (SFG) rickettsiae are obligate intracellular bacteria transmitted by ticks that cause several tick-borne rickettsioses in humans worldwide. This study was intended to determine the prevalence of SFG rickettsiae in Amblyomma variegatum from 7 districts across Uganda. In addition to sequencing of gltA and ompA genes, identification of Rickettsia species based on the sizes of highly variable intergenic spacers, namely, dksA-xerC, mppA-purC, and rpmE-tRNA(fMet) was carried out. Application of multiplex PCR for simultaneous amplification of 3 spacers combined with capillary electrophoresis separation allowed simple, accurate, and high-throughput fragment sizing with considerable time and cost savings. Rickettsia genus-specific real-time PCR detected 136 positives out of 140 samples, giving an overall prevalence of 97.1%. Most samples (n=113) had a size combination of 225, 195, and 341 bp for dksA-xerC, mppA-purC, and rpmE-tRNA(fMet), respectively, which was identical to that of R. africae, a causative agent of African tick bite fever. In addition, several samples had size variants in either dksA-xerC or rpmE-tRNA(fMet). Nonetheless, the partial sequences of gltA and ompA genes of samples of all size combinations showed the greatest similarity to R. africae (99.3-100% for gltA and 98.1-100% for ompA). Given these results, it is highly possible that the tested ticks were infected with R. africae or closely related species. This is a first report on molecular genetic detection of R. africae and its high endemicity in Uganda. Clinicians in this country should be aware of this pathogen as a cause of non-malarial febrile illness. This study provided a starting point for the development of Rickettsia species identification based on the sizes of intergenic spacers. The procedure is simple, rapid, and cost-effective to perform; hence it might be particularly well suited for preliminary species identification in epidemiological investigations. The results

  16. Rickettsia lusitaniae sp. nov. isolated from the soft tick Ornithodoros erraticus (Acarina: Argasidae).

    Science.gov (United States)

    Milhano, Natacha; Palma, Mariana; Marcili, Arlei; Núncio, Maria Sofia; de Carvalho, Isabel Lopes; de Sousa, Rita

    2014-05-01

    In this study a novel Rickettsia from the spotted fever group, isolated from Ornithodoros erraticus soft ticks collected from pigpens in the south of Portugal, is described. After initial screening revealed Rickettsia-positive ticks, isolation attempts were then performed. Successful isolates were achieved by shell-vial technique using Vero E6 cells at 28°C. Molecular characterization of the isolate was performed based on analysis of five rickettsial genes gltA, ompA, ompB, sca1 and htr with their subsequent concatenation along with other rickettsial species resulting in a clustering of the new isolate with Rickettsia felis and Rickettsia hoogstraalii. The degree of nucleotide sequence similarity with other rickettsiae fulfills the criteria for classification of our isolate as a novel species. The name Rickettsia lusitaniae sp. nov. (=CEVDI PoTiRo) is proposed for this new species found in O. erraticus.

  17. Transposon Insertion Reveals pRM, a Plasmid of Rickettsia monacensis▿

    OpenAIRE

    Baldridge, Gerald D.; Burkhardt, Nicole Y.; Felsheim, Roderick F.; Timothy J Kurtti; Munderloh, Ulrike G.

    2007-01-01

    Until the recent discovery of pRF in Rickettsia felis, the obligate intracellular bacteria of the genus Rickettsia (Rickettsiales: Rickettsiaceae) were thought not to possess plasmids. We describe pRM, a plasmid from Rickettsia monacensis, which was detected by pulsed-field gel electrophoresis and Southern blot analyses of DNA from two independent R. monacensis populations transformed by transposon-mediated insertion of coupled green fluorescent protein and chloramphenicol acetyltransferase m...

  18. Antibodies to Rickettsia spp. and Borrelia burgdorferi in Spanish Wild Red Foxes (Vulpes vulpes).

    Science.gov (United States)

    Lledó, Lourdes; Serrano, José Luis; Isabel Gegúndez, María; Giménez-Pardo, Consuelo; Saz, José Vicente

    2016-01-01

    We examined 314 red foxes (Vulpes vulpes) from the province of Soria, Spain, for Rickettsia typhi, Rickettsia slovaca, and Borrelia burgdorferi infection. Immunofluorescence assays showed 1.9% had antibodies to R. typhi, 6.7% had antibodies to R. slovaca, and 8.3% had antibodies to B. burgdorferi. Serostatus was not correlated with sex or age. Because red foxes can be infected by Rickettsiae and B. burgdorferi, presence of red foxes may be and indicator for the presence of these pathogens.

  19. Ixodes pacificus ticks maintain embryogenesis and egg hatching after antibiotic treatment of Rickettsia endosymbiont.

    Science.gov (United States)

    Kurlovs, Andre H; Li, Jinze; Cheng, Du; Zhong, Jianmin

    2014-01-01

    Rickettsia is a genus of intracellular bacteria that causes a variety of diseases in humans and other mammals and associates with a diverse group of arthropods. Although Rickettsia appears to be common in ticks, most Rickettsia-tick relationships remain generally uncharacterized. The most intimate of these associations is Rickettsia species phylotype G021, a maternally and transstadially transmitted endosymbiont that resides in 100% of I. pacificus in California. We investigated the effects of this Rickettsia phylotype on I. pacificus reproductive fitness using selective antibiotic treatment. Ciprofloxacin was 10-fold more effective than tetracycline in eliminating Rickettsia from I. pacificus, and quantitative PCR results showed that eggs from the ciprofloxacin-treated ticks contained an average of 0.02 Rickettsia per egg cell as opposed to the average of 0.2 in the tetracycline-treated ticks. Ampicillin did not significantly affect the number of Rickettsia per tick cell in adults or eggs compared to the water-injected control ticks. We found no relationship between tick embryogenesis and rickettsial density in engorged I. pacificus females. Tetracycline treatment significantly delayed oviposition of I. pacificus ticks, but the antibiotic's effect was unlikely related to Rickettsia. We also demonstrated that Rickettsia-free eggs could successfully develop into larvae without any significant decrease in hatching compared to eggs containing Rickettsia. No significant differences in the incubation period, egg hatching rate, and the number of larvae were found between any of the antibiotic-treated groups and the water-injected tick control. We concluded that Rickettsia species phylotype G021 does not have an apparent effect on embryogenesis, oviposition, and egg hatching of I. pacificus.

  20. INFECTION BY Rickettsia felis IN OPOSSUMS (Didelphis sp.) FROM YUCATAN, MEXICO.

    Science.gov (United States)

    Peniche-Lara, Gaspar; Ruiz-Piña, Hugo A; Reyes-Novelo, Enrique; Dzul-Rosado, Karla; Zavala-Castro, Jorge

    2016-01-01

    Rickettsia felis is an emergent pathogen and the causative agent of a typhus-like rickettsiosis in the Americas. Its transmission cycle involves fleas as biological vectors (mainly Ctenocephalides felis) and multiple domestic and synanthropic mammal hosts. Nonetheless, the role of mammals in the cycle of R. felis is not well understood and many efforts are ongoing in different countries of America to clarify it. The present study describes for the first time in Mexico the infection of two species of opossum (Didelphis virginiana and D. marsupialis) by R. felis. A diagnosis was carried out from blood samples by molecular methods through the gltA and 17 kDa genes and sequence determination. Eighty-seven opossum samples were analyzed and 28 were found to be infected (32.1%) from five out of the six studied localities of Yucatan. These findings enable recognition of the potential epidemiological implications for public health of the presence of infected synanthropic Didelphis in households.

  1. Rickettsia infection in Amblyomma tonelliae, a tick species from the Amblyomma cajennense complex.

    Science.gov (United States)

    Tarragona, Evelina L; Cicuttin, Gabriel L; Mangold, Atilio J; Mastropaolo, Mariano; Nazarena De Salvo, M; Nava, Santiago

    2015-03-01

    The present study was performed to evaluate the Rickettsia infection in Amblyomma tonelliae ticks from Argentina. All ticks were subjected to DNA extraction and tested by a battery of PCRs to amplify fragments of four rickettsial genes, 23S-5S, gltA, ompA and htrA. Two ticks were positive. The Rickettsia detected in one tick represents a new lineage which is named Rickettsia sp. strain El Tunal. This new strain belongs to the canadensis group because it is closely related to Rickettsia monteiroi, Rickettsia canadensis and Candidatus "Rickettsia tarasevichiae". They clustered together on a high supported clade with both gltA and htrA genes. The other positive tick was infected with Candidatus "Rickettsia amblyommii". The results presented in this study constitute the first records of Rickettsia infection in A. tonelliae ticks. However, the medical relevance of these findings should be considered cautiously because the pathogenicity of Rickettsia sp. strain El Tunal and Candidatus "R. amblyommii" remains undetermined.

  2. Molecular detection of the human pathogenic Rickettsia sp. strain Atlantic rainforest in Amblyomma dubitatum ticks from Argentina.

    Science.gov (United States)

    Monje, Lucas D; Nava, Santiago; Eberhardt, Ayelen T; Correa, Ana I; Guglielmone, Alberto A; Beldomenico, Pablo M

    2015-02-01

    To date, three tick-borne pathogenic Rickettsia species have been reported in different regions of Argentina, namely, R. rickettsii, R. parkeri, and R. massiliae. However, there are no reports available for the presence of tick-borne pathogens from the northeastern region of Argentina. This study evaluated the infection with Rickettsia species of Amblyomma dubitatum ticks collected from vegetation and feeding from capybaras (Hydrochoerus hydrochaeris) in northeastern Argentina. From a total of 374 A. dubitatum ticks collected and evaluated by PCR for the presence of rickettsial DNA, 19 were positive for the presence of Rickettsia bellii DNA, two were positive for Rickettsia sp. strain COOPERI, and one was positive for the pathogenic Rickettsia sp. strain Atlantic rainforest. To our knowledge, this study is the first report of the presence of the human pathogen Rickettsia sp. strain Atlantic rainforest and Rickettsia sp. strain COOPERI in Argentina. Moreover, our findings posit A. dubitatum as a potential vector for this pathogenic strain of Rickettsia.

  3. Isolation of Rickettsia parkeri and identification of a novel spotted fever group Rickettsia sp. from Gulf Coast ticks (Amblyomma maculatum) in the United States.

    Science.gov (United States)

    Paddock, Christopher D; Fournier, Pierre-Edouard; Sumner, John W; Goddard, Jerome; Elshenawy, Yasmin; Metcalfe, Maureen G; Loftis, Amanda D; Varela-Stokes, Andrea

    2010-05-01

    Until recently, Amblyomma maculatum (the Gulf Coast tick) had garnered little attention compared to other species of human-biting ticks in the United States. A. maculatum is now recognized as the principal vector of Rickettsia parkeri, a pathogenic spotted fever group rickettsia (SFGR) that causes an eschar-associated illness in humans that resembles Rocky Mountain spotted fever. A novel SFGR, distinct from other recognized Rickettsia spp., has also been detected recently in A. maculatum specimens collected in several regions of the southeastern United States. In this study, 198 questing adult Gulf Coast ticks were collected at 4 locations in Florida and Mississippi; 28% of these ticks were infected with R. parkeri, and 2% of these were infected with a novel SFGR. Seventeen isolates of R. parkeri from individual specimens of A. maculatum were cultivated in Vero E6 cells; however, all attempts to isolate the novel SFGR were unsuccessful. Partial genetic characterization of the novel SFGR revealed identity with several recently described, incompletely characterized, and noncultivated SFGR, including "Candidatus Rickettsia andeanae" and Rickettsia sp. Argentina detected in several species of Neotropical ticks from Argentina and Peru. These findings suggest that each of these "novel" rickettsiae represent the same species. This study considerably expanded the number of low-passage, A. maculatum-derived isolates of R. parkeri and characterized a second, sympatric Rickettsia sp. found in Gulf Coast ticks.

  4. Molecular Detection of Rickettsia amblyommii in Amblyomma americanum Parasitizing Humans

    Science.gov (United States)

    2010-01-01

    Maeda, K, Markowitz, N, Hawley, RC, Ristic, M, et al. Human infection with Ehrlichia canis , a leukocytic rickettsia. N Eng! J Med 1987; 316:853-856...lone star tick human pathogens Ehrlichia chaffenesis (human monocytic ehrlichiosis [HMEJ) and Ehrlichia ezoingii (E. ezoingii ehrlichiosis [EWE...Paddock, CD, et al. Ehrlichia ewingii, a newly recognized agent of human ehrlichiosis. N Engl J Med 1999; 341:148-155. Burgdorfer, W, Hayes, S

  5. Limited transcriptional responses of Rickettsia rickettsii exposed to environmental stimuli.

    Directory of Open Access Journals (Sweden)

    Damon W Ellison

    Full Text Available Rickettsiae are strict obligate intracellular pathogens that alternate between arthropod and mammalian hosts in a zoonotic cycle. Typically, pathogenic bacteria that cycle between environmental sources and mammalian hosts adapt to the respective environments by coordinately regulating gene expression such that genes essential for survival and virulence are expressed only upon infection of mammals. Temperature is a common environmental signal for upregulation of virulence gene expression although other factors may also play a role. We examined the transcriptional responses of Rickettsia rickettsii, the agent of Rocky Mountain spotted fever, to a variety of environmental signals expected to be encountered during its life cycle. R. rickettsii exposed to differences in growth temperature (25 degrees C vs. 37 degrees C, iron limitation, and host cell species displayed nominal changes in gene expression under any of these conditions with only 0, 5, or 7 genes, respectively, changing more than 3-fold in expression levels. R. rickettsii is not totally devoid of ability to respond to temperature shifts as cold shock (37 degrees C vs. 4 degrees C induced a change greater than 3-fold in up to 56 genes. Rickettsiae continuously occupy a relatively stable environment which is the cytosol of eukaryotic cells. Because of their obligate intracellular character, rickettsiae are believed to be undergoing reductive evolution to a minimal genome. We propose that their relatively constant environmental niche has led to a minimal requirement for R. rickettsii to respond to environmental changes with a consequent deletion of non-essential transcriptional response regulators. A minimal number of predicted transcriptional regulators in the R. rickettsii genome is consistent with this hypothesis.

  6. Limited Transcriptional Responses of Rickettsia rickettsii Exposed to Environmental Stimuli

    OpenAIRE

    Ellison, Damon W.; Clark, Tina R.; Sturdevant, Daniel E.; Kimmo Virtaneva; Ted Hackstadt

    2009-01-01

    Rickettsiae are strict obligate intracellular pathogens that alternate between arthropod and mammalian hosts in a zoonotic cycle. Typically, pathogenic bacteria that cycle between environmental sources and mammalian hosts adapt to the respective environments by coordinately regulating gene expression such that genes essential for survival and virulence are expressed only upon infection of mammals. Temperature is a common environmental signal for upregulation of virulence gene expression altho...

  7. Common epidemiology of Rickettsia felis infection and malaria, Africa.

    Science.gov (United States)

    Mediannikov, Oleg; Socolovschi, Cristina; Edouard, Sophie; Fenollar, Florence; Mouffok, Nadjet; Bassene, Hubert; Diatta, Georges; Tall, Adama; Niangaly, Hamidou; Doumbo, Ogobara; Lekana-Douki, Jean Bernard; Znazen, Abir; Sarih, M'hammed; Ratmanov, Pavel; Richet, Herve; Ndiath, Mamadou O; Sokhna, Cheikh; Parola, Philippe; Raoult, Didier

    2013-11-01

    This study aimed to compare the epidemiology of Rickettsia felis infection and malaria in France, North Africa, and sub-Saharan Africa and to identify a common vector. Blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for R. felis and Plasmodium spp. We observed a significant linear trend (pAfrica also protects against rickettsioses; thus, empirical treatment strategies for febrile illness for travelers and residents in sub-Saharan Africa may require reevaluation.

  8. Detection of Rickettsia bellii and Rickettsia amblyommii in Amblyomma longirostre (Acari: Ixodidae) from Bahia state, Northeast Brazil.

    Science.gov (United States)

    McIntosh, Douglas; Bezerra, Rodrigo Alves; Luz, Hermes Ribeiro; Faccini, João Luiz Horacio; Gaiotto, Fernanda Amato; Giné, Gastón Andrés Fernandez; Albuquerque, George Rego

    2015-01-01

    Studies investigating rickettsial infections in ticks parasitizing wild animals in the Northeast region of Brazil have been confined to the detection of Rickettsia amblyommii in immature stages of Amblyomma longirostre collected from birds in the state of Bahia, and in immatures and females of Amblyomma auricularium collected from the striped hog-nosed skunk (Conepatus semistriatus) and armadillos (Euphractus sexcinctus) in the state of Pernambuco. The current study extends the distribution of R. amblyommii (strain Aranha), which was detected in A. longirostre collected from the thin-spined porcupine Chaetomys subspinosus and the hairy dwarf porcupine Coendou insidiosus. In addition, we report the first detection of Rickettsia bellii in adults of A. longirostre collected from C. insidiosus in the state of Bahia.

  9. Spotted fever group rickettsia closely related to Rickettsia monacensis isolated from ticks in South Jeolla province, Korea.

    Science.gov (United States)

    Lee, Kyung-Min; Choi, Yeon-Joo; Shin, Sun-Hye; Choi, Min-Kyung; Song, Hyeon-Je; Kim, Heung-Chul; Klein, Terry A; Richards, Allen L; Park, Kyung-Hee; Jang, Won-Jong

    2013-07-01

    Rickettsia monacensis, a spotted fever group rickettsia, was isolated from Ixodes nipponensis ticks collected from live-captured small mammals in South Jeolla province, Korea in 2006. Homogenates of tick tissues were inoculated into L929 and Vero cell monolayers using shell vial assays. After several passages, Giemsa staining revealed rickettsia-like organisms in the inoculated Vero cells, but not the L929 cells. Sequencing analysis revealed that the ompA-small part (25-614 bp region), ompA-large part (2849-4455 bp region), nearly full-length ompB (58-4889 bp region) and gltA (196-1236 bp region) of the isolates had similarities of 100%, 99.8%, 99.3% and 99.5%, respectively, to those of R. monacensis. Furthermore, phylogenetic analysis showed that the isolate was grouped into the cluster in the same way as R. monacensis in the trees of all genes examined. These results strongly suggest that the isolate is closely related to R. monacensis. As far as is known, this is the first report of isolation of R. monacensis from ticks in Korea.

  10. Rickettsia spp. in seabird ticks from western Indian Ocean islands, 2011-2012.

    Science.gov (United States)

    Dietrich, Muriel; Lebarbenchon, Camille; Jaeger, Audrey; Le Rouzic, Céline; Bastien, Matthieu; Lagadec, Erwan; McCoy, Karen D; Pascalis, Hervé; Le Corre, Matthieu; Dellagi, Koussay; Tortosa, Pablo

    2014-05-01

    We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.

  11. High prevalence of Rickettsia spp. infections in small mammals in Taiwan.

    Science.gov (United States)

    Kuo, Chi-Chien; Shu, Pei-Yun; Mu, Jung-Jung; Wang, Hsi-Chieh

    2015-01-01

    Surveillance for Rickettsia spp. is urgently needed due to the recent emergence of many novel rickettsioses around the globe, but previous studies in Taiwan have been limited to small areas and no investigation of infections in vertebrate hosts has ever been attempted. We surveyed rickettsial infections systematically in small-mammal hosts trapped between 2006 and 2010 throughout Taiwan. Fragments of ompB and gltA genes in the liver, spleen, and kidney of mammals were targeted by nested polymerase chain reaction. We trapped 1375 individuals of 10 species, among which Rattus losea was the most common (54.6%), followed by Suncus murinus (20.6%) and Mus caroli (10.6%). The overall rate of Rickettsia infections in the liver, spleen, or kidney of 309 assayed small mammals was 60.5%, with a rate of infection ≥50% for each mammal species. DNA nucleotide sequences of 184 successfully sequenced genes were most similar to nine Rickettsia species: Rickettsia conorii, R. felis, R. japonica, R. raoultii, R. rickettsii, Rickettsia sp. IG-1, Rickettsia sp. TwKM01, Rickettsia sp. TwKM02, and R. typhi. Our results suggest that several novel Rickettsia spp. are common and widespread across various habitats throughout Taiwan and suggest the need for further study of emerging rickettsioses in Taiwan.

  12. Molecular Method for Identification of Rickettsia Species in Clinical and Environmental Samples▿

    Science.gov (United States)

    Jado, Isabel; Escudero, Raquel; Gil, Horacio; Jiménez-Alonso, María Isabel; Sousa, Rita; García-Pérez, Ana L.; Rodríguez-Vargas, Manuela; Lobo, Bruno; Anda, Pedro

    2006-01-01

    We present a PCR method targeting the 23S-5S internal transcribed spacer coupled with reverse line blotting that allows Rickettsia species detection and identification in a single step. The method is highly sensitive and specific in identifying Rickettsia species from both patient and environmental samples. The generic approach used allowed us to identify new pathogens. PMID:17035495

  13. Plasmids of the pRM/pRF family occur in diverse Rickettsia species.

    Science.gov (United States)

    Baldridge, Gerald D; Burkhardt, Nicole Y; Felsheim, Roderick F; Kurtti, Timothy J; Munderloh, Ulrike G

    2008-02-01

    The recent discoveries of the pRF and pRM plasmids of Rickettsia felis and R. monacensis have contravened the long-held dogma that plasmids are not present in the bacterial genus Rickettsia (Rickettsiales; Rickettsiaceae). We report the existence of plasmids in R. helvetica, R. peacockii, R. amblyommii, and R. massiliae isolates from ixodid ticks and in an R. hoogstraalii isolate from an argasid tick. R. peacockii and four isolates of R. amblyommii from widely separated geographic locations contained plasmids that comigrated with pRM during pulsed-field gel electrophoresis and larger plasmids with mobilities similar to that of pRF. The R. peacockii plasmids were lost during long-term serial passage in cultured cells. R. montanensis did not contain a plasmid. Southern blots showed that sequences similar to those of a DnaA-like replication initiator protein, a small heat shock protein 2, and the Sca12 cell surface antigen genes on pRM and pRF were present on all of the plasmids except for that of R. massiliae, which lacked the heat shock gene and was the smallest of the plasmids. The R. hoogstraalii plasmid was most similar to pRM and contained apparent homologs of proline/betaine transporter and SpoT stringent response genes on pRM and pRF that were absent from the other plasmids. The R. hoogstraalii, R. helvetica, and R. amblyommii plasmids contained homologs of a pRM-carried gene similar to a Nitrobacter sp. helicase RecD/TraA gene, but none of the plasmids hybridized with a probe derived from a pRM-encoded gene similar to a Burkholderia sp. transposon resolvase gene.

  14. Prostatitis, Steatitis, and Diarrhea in a Dog following Presumptive Flea-Borne Transmission of Bartonella henselae

    Science.gov (United States)

    Balakrishnan, Nandhakumar; Pritchard, Jessica; Ericson, Marna; Grindem, Carol; Phillips, Kathryn; Jennings, Samuel; Mathews, Kyle; Tran, Huy; Birkenheuer, Adam J.

    2014-01-01

    Bartonella henselae is increasingly associated with a variety of pathological entities, which are often similar in dogs and human patients. Following an acute flea infestation, a dog developed an unusual clinical presentation for canine bartonellosis. Comprehensive medical, microbiological, and surgical interventions were required for diagnosis and to achieve a full recovery. PMID:24920774

  15. Managing iron supply during the infection cycle of a flea borne pathogen, Bartonella henselae.

    Directory of Open Access Journals (Sweden)

    Francis eBiville

    2013-10-01

    Full Text Available Bartonella are hemotropic bacteria responsible for emerging zoonoses. Most Bartonella species appear to share a natural cycle that involves an arthropod transmission, followed by exploitation of a mammalian host in which they cause long-lasting intra-erythrocytic bacteremia. Persistence in erythrocytes is considered an adaptation to transmission by bloodsucking arthropod vectors and a strategy to obtain heme required for Bartonella growth. Bartonella genomes do not encode for siderophore biosynthesis or a complete iron Fe3+ transport system. Only genes, sharing strong homology with all compounds of a Fe2+ transport system, are present in Bartonella genomes. Also, Bartonella genomes encode for a complete heme transport system. Bartonella must face various environments in their hosts and vectors. In mammals, free heme and iron are rare and oxygen concentration is low. In arthropod vectors, toxic heme level is found in the gut where oxygen concentration is high. Bartonella genomes encode for three to five heme binding proteins. In Bartonella henselae heme binding proteins were shown to be involved in heme uptake process, oxidative stress response and survival inside endothelial cells and in the flea. In this report, we discuss the use of the heme uptake and storage system of B. henselae during its infection cycle. Also, we establish a comparison with the use of the iron and heme uptake systems by Yersinia pestis during its infection cycle.

  16. Infection of Amblyomma ovale with Rickettsia species Atlantic rainforest in Serra do Mar, São Paulo State, Brazil.

    Science.gov (United States)

    Luz, Hermes Ribeiro; McIntosh, Douglas; Furusawa, Guilherme P; Flausino, Walter; Rozental, Tatiana; Lemos, Elba R S; Landulfo, Gabriel A; Faccini, João Luiz H

    2016-10-01

    Rickettsia rickettsii and Rickettsia sp. strain Atlantic rainforest, that is considered to represent a genetic variant of Rickettsia parkeri, are confirmed as being capable of infecting humans in Brazil. This study reports the detection and characterization, by PCR and nucleotide sequencing, of Rickettsia sp. strain Atlantic rain forest in Amblyomma ovale parasitizing a human, in ticks infesting dogs and in free-living ticks collected from the environment where the human infestation was recorded. The data contribute to our knowledge of infection rates in A. ovale with Rickettsia sp. strain Atlantic rainforest and identified an additional location in the state of São Paulo populated with ticks infected with this emerging pathogen.

  17. Human Infection with Rickettsia felis, Kenya

    Science.gov (United States)

    2010-07-01

    Prescribed by ANSI Std Z39-18 RESEARCH rickeltsiosis, brucellosis . leptospirosis, and other viral in- fections. The study protocol was approved by the...sheep, goats , and camels; and carries a wide range of wi ldl ife. including zebras, ante- lopes. waterbucks. giraffes, warthogs, monkeys. gerenuks...contact with livestock animals such as cattle, sheep, goats , or camels. Although this was not captured in the question- naire, almost all livestock

  18. Sca1, a previously undescribed paralog from autotransporter protein-encoding genes in Rickettsia species

    Directory of Open Access Journals (Sweden)

    Raoult Didier

    2006-02-01

    Full Text Available Abstract Background Among the 17 genes encoding autotransporter proteins of the "surface cell antigen" (sca family in the currently sequenced Rickettsia genomes, ompA, sca5 (ompB and sca4 (gene D, have been extensively used for identification and phylogenetic purposes for Rickettsia species. However, none of these genes is present in all 20 currently validated Rickettsia species. Of the remaining 14 sca genes, sca1 is the only gene to be present in all nine sequenced Rickettsia genomes. To estimate whether the sca1 gene is present in all Rickettsia species and its usefulness as an identification and phylogenetic tool, we searched for sca1genes in the four published Rickettsia genomes and amplified and sequenced this gene in the remaining 16 validated Rickettsia species. Results Sca1 is the only one of the 17 rickettsial sca genes present in all 20 Rickettsia species. R. prowazekii and R. canadensis exhibit a split sca1 gene whereas the remaining species have a complete gene. Within the sca1 gene, we identified a 488-bp variable sequence fragment that can be amplified using a pair of conserved primers. Sequences of this fragment are specific for each Rickettsia species. The phylogenetic organization of Rickettsia species inferred from the comparison of sca1 sequences strengthens the classification based on the housekeeping gene gltA and is similar to those obtained from the analyses of ompA, sca5 and sca4, thus suggesting similar evolutionary constraints. We also observed that Sca1 protein sequences have evolved under a dual selection pressure: with the exception of typhus group rickettsiae, the amino-terminal part of the protein that encompasses the predicted passenger domain, has evolved under positive selection in rickettsiae. This suggests that the Sca1 protein interacts with the host. In contrast, the C-terminal portion containing the autotransporter domain has evolved under purifying selection. In addition, sca1 is transcribed in R. conorii

  19. [Lymphangitis-associated rickettsiosis caused by Rickettsia sibirica mongolitimonae].

    Science.gov (United States)

    Foissac, M; Socolovschi, C; Raoult, D

    2013-01-01

    Rickettsia sibirica mongolitimonae was first isolated 20 years ago in Asia but has now been identified on three continents. Hyalomma spp. and Rhipicephalus pusillus ticks are vectors but only a small number of cases have been reported to date, mainly on the Mediterranean coast. This bacterium induces the lymphangitis-associated rickettsiosis, a still unfamiliar rickettsiosis that is mainly characterized by fever with a rope-like lymphangitis and/or lymphadenopathy and skin eschar occurring after tick bites. These features are especially evocative if they occur in spring. Sequellae are very rare and treatment with doxycycline is recommended.

  20. Prevalence of infection with Rickettsia helvetica in Ixodes ricinus ticks feeding on non-rickettsiemic rodent hosts in sylvatic habitats of west-central Poland.

    Science.gov (United States)

    Biernat, Beata; Stańczak, Joanna; Michalik, Jerzy; Sikora, Bożena; Wierzbicka, Anna

    2016-02-01

    Ixodes ricinus is the most prevalent and widely distributed tick species in European countries and plays a principal role in transmission of a wide range of microbial pathogens. It is also a main vector and reservoir of Rickettsia spp. of the spotted fever group with the infection level ranging in Poland from 1.3% to 11.4%. Nevertheless, little research has been conducted so far to identify reservoir hosts for these pathogens. A survey was undertaken to investigate the presence of Rickettsia spp. in wild small rodents and detached I. ricinus. Rodents, Apodemus flavicollis mice and Myodes glareolus voles were captured in typically sylvatic habitats of west-central Poland. Blood samples and collected ticks were analyzed by conventional, semi-nested and nested PCRs. Rickettsial species were determined by sequence analysis of obtained fragments of gltA and 16S rRNA genes. A total of 2339 immature I. ricinus (mostly larvae) were collected from 158 animals. Proportion of hosts carrying ticks was 84%, being higher for A. flavicollis than for M. glareolus. Rickettsia helvetica, the only species identified, was detected in 8% of 12 nymphs and in at least 10.7% (MIR) of 804 larvae investigated. Prevalence of infected ticks on both rodent species was comparable (10.8 vs. 9%). None of blood samples tested was positive for Rickettsia spp. The results showed that in sylvatic habitats the level of infestation with larval I. ricinus was higher in A. flavicollis mice in comparison with M. glareolus voles. They show that R. helvetica frequently occurred in ticks feeding on rodents. Positive immature ticks were collected from non-rickettsiemic hosts what might suggest a vertical route of their infection (transovarial and/or transstadial) or a very short-lasting rickettsiemia in rodents. A natural vertebrate reservoir host for R. helvetica remains to be determined.

  1. Characterization of the symbiont Rickettsia in the mirid bug Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae).

    Science.gov (United States)

    Caspi-Fluger, A; Inbar, M; Steinberg, S; Friedmann, Y; Freund, M; Mozes-Daube, N; Zchori-Fein, E

    2014-12-01

    Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae) is an omnivorous insect used for biological control. Augmentative release and conservation of N. tenuis have been used for pest control in tomato crops. Intracellular bacterial symbionts of arthropods are common in nature and have diverse effects on their hosts; in some cases they can dramatically affect biological control. Fingerprinting methods showed that the symbiotic complex associated with N. tenuis includes Wolbachia and Rickettsia. Rickettsia of N. tenuis was further characterized by sequencing the 16S rRNA and gltA bacterial genes, measuring its amount in different developmental stages of the insect by real-time polymerase chain reaction, and localizing the bacteria in the insect's body by fluorescence in situ hybridization. The Rickettsia in N. tenuis exhibited 99 and 96% similarity of both sequenced genes to Rickettsia bellii and Rickettsia reported from Bemisia tabaci, respectively. The highest amount of Rickettsia was measured in the 5th instar and adult, and the symbionts could be detected in the host gut and ovaries. Although the role played by Rickettsia in the biology of N. tenuis is currently unknown, their high amount in the adults and localization in the gut suggest that they may have a nutritional role in this insect.

  2. Rickettsial ompB promoter regulated expression of GFPuv in transformed Rickettsia montanensis.

    Directory of Open Access Journals (Sweden)

    Gerald D Baldridge

    Full Text Available Rickettsia spp. (Rickettsiales: Rickettsiaceae are Gram-negative, obligate intracellular, alpha-proteobacteria that have historically been associated with blood-feeding arthropods. Certain species cause typhus and spotted fevers in humans, but others are of uncertain pathogenicity or may be strict arthropod endosymbionts. Genetic manipulation of rickettsiae should facilitate a better understanding of their interactions with hosts.We transformed a species never associated with human disease, Rickettsia montanensis, by electroporation with a TN5 transposon (pMOD700 containing green fluorescent protein (GFPuv and chloramphenicol acetyltransferase (CAT genes under regulation of promoters cloned from the Rickettsia rickettsii ompB gene, and isolated a Chloramphenicol-resistant GFP-fluorescent rickettsiae population (Rmontanensis700. The Rmontanensis700 rickettsiae contained a single transposon integrated near an acetyl-CoA acetyltransferase gene in the rickettsial chromosome. Northern blots showed that GFPuv and CAT mRNAs were both expressed as two transcripts of larger and smaller than predicted length. Western immunoblots showed that Rmontanensis700 and E. coli transformed with a plasmid containing the pMOD700 transposon both expressed GFPuv proteins of the predicted molecular weight.Long-standing barriers to transformation of rickettsiae have been overcome by development of transposon-based rickettsial transformation vectors. The ompB promoter may be the most problematic of the four promoters so far employed in those vectors.

  3. Detection and prevalence of Anaplasma phagocytophilum and Rickettsia helvetica in Ixodes ricinus ticks in seven study areas in Sweden

    Directory of Open Access Journals (Sweden)

    Falk Kerstin

    2010-08-01

    Full Text Available Abstract Background Tick-borne Anaplasma phagocytophilum and Rickettsia spp. are considered to be emerging human pathogens, but only limited data are available on their occurrence in Sweden. Two real-time PCR assays followed by nested PCR and sequence analysis were carried out to investigate the prevalence of A. phagocytophilum and spotted fever rickettsiae in ticks from seven areas in Sweden. Results In 139 pooled samples, representing a total of 1245 Ixodes ricinus ticks (204 larvae, 963 nymphs, 38 males, 40 females, the overall positive mean infection prevalence was 1.3-15.0% for A. phagocytophilum and 1.5-17.3% for R. helvetica. A. phagocytophilum was only detected in nymphs (1.7-19.4%, whereas R. helvetica was detected in all three tick stages. Support for vertical and transstadial transmission was only obtained for R. helvetica. Both agents showed similar infection rates across study areas, although infection rates were greater in coastal areas. Conclusions The results show that both pathogens occurred in all seven locations, indicating that they are prevalent in Sweden and should be considered etiological agents in patients recently bitten by ticks.

  4. Shell-vial culture and real-time PCR applied to Rickettsia typhi and Rickettsia felis detection.

    Science.gov (United States)

    Segura, Ferran; Pons, Immaculada; Pla, Júlia; Nogueras, María-Mercedes

    2015-11-01

    Murine typhus is a zoonosis transmitted by fleas, whose etiological agent is Rickettsia typhi. Rickettsia felis infection can produces similar symptoms. Both are intracellular microorganisms. Therefore, their diagnosis is difficult and their infections can be misdiagnosed. Early diagnosis prevents severity and inappropriate treatment regimens. Serology can't be applied during the early stages of infection because it requires seroconversion. Shell-vial (SV) culture assay is a powerful tool to detect Rickettsia. The aim of the study was to optimize SV using a real-time PCR as monitoring method. Moreover, the study analyzes which antibiotics are useful to isolate these microorganisms from fleas avoiding contamination by other bacteria. For the first purpose, SVs were inoculated with each microorganism. They were incubated at different temperatures and monitored by real-time PCR and classical methods (Gimenez staining and indirect immunofluorescence assay). R. typhi grew at all temperatures. R. felis grew at 28 and 32 °C. Real-time PCR was more sensitive than classical methods and it detected microorganisms much earlier. Besides, the assay sensitivity was improved by increasing the number of SV. For the second purpose, microorganisms and fleas were incubated and monitored in different concentrations of antibiotics. Gentamicin, sufamethoxazole, trimethoprim were useful for R. typhi isolation. Gentamicin, streptomycin, penicillin, and amphotericin B were useful for R. felis isolation. Finally, the optimized conditions were used to isolate R. felis from fleas collected at a veterinary clinic. R. felis was isolated at 28 and 32 °C. However, successful establishment of cultures were not possible probably due to sub-optimal conditions of samples.

  5. Molecular Detection of Rickettsia Species Within Ticks (Acari: Ixodidae) Collected from Arkansas United States.

    Science.gov (United States)

    Trout Fryxell, R T; Steelman, C D; Szalanski, A L; Billingsley, P M; Williamson, P C

    2015-05-01

    Rocky Mountain spotted fever (RMSF), caused by the etiological agent Rickettsia rickettsii, is the most severe and frequently reported rickettsial illness in the United States, and is commonly diagnosed throughout the southeast. With the discoveries of Rickettsia parkeri and other spotted fever group rickettsiae (SFGR) in ticks, it remains inconclusive if the cases reported as RMSF are truly caused by R. rickettsii or other SFGR. Arkansas reports one of the highest incidence rates of RMSF in the country; consequently, to identify the rickettsiae in Arkansas, 1,731 ticks, 250 white-tailed deer, and 189 canines were screened by polymerase chain reaction (PCR) for the rickettsial genes gltA, rompB, and ompA. None of the white-tailed deer were positive, while two of the canines (1.1%) and 502 (29.0%) of the ticks were PCR positive. Five different tick species were PCR positive: 244 (37%) Amblyomma americanum L., 130 (38%) Ixodes scapularis Say, 65 (39%) Amblyomma maculatum (Koch), 30 (9%) Rhipicephalus sanguineus Latreille, 7 (4%) Dermacentor variabilis Say, and 26 (44%) unidentified Amblyomma ticks. None of the sequenced products were homologous to R. rickettsii. The most common Rickettsia via rompB amplification was Rickettsia montanensis and nonpathogenic Candidatus Rickettsia amblyommii, whereas with ompA amplification the most common Rickettsia was Ca. R. amblyommii. Many tick specimens collected in northwest Arkansas were PCR positive and these were commonly A. americanum harboring Ca. R. amblyommii, a currently nonpathogenic Rickettsia. Data reported here indicate that pathogenic R. rickettsii was absent from these ticks and suggest by extension that other SFGR are likely the causative agents for Arkansas diagnosed RMSF cases.

  6. Rickettsia bellii in Amblyomma rotundatum ticks parasitizing Rhinella jimi from northeastern Brazil.

    Science.gov (United States)

    Horta, Mauricio C; Saraiva, Danilo G; Oliveira, Glauber M B; Martins, Thiago F; Labruna, Marcelo B

    2015-01-01

    This study evaluated rickettsial infection in Amblyomma rotundatum ticks collected from toads (Rhinella jimi) in the Brazilian Caatinga biome, an unique semiarid region of South America. Tick infestations were observed in 57.8% toads (26/45); mean infestation: 1.6 ticks/toad. DNA extraction from 42 ticks (6 larvae, 22 nymphs and 11 female adults) was tested by polymerase chain reaction (PCR) targeting Rickettsia organisms, which were detected in 100% of the ticks. Amplicons' DNA sequences were identical to each other and 99% identical to Rickettsia bellii from GenBank. DNA samples extracted from the blood of the 45 toads were negative by rickettsia-PCR protocols.

  7. Comparative growth of spotted fever group Rickettsia spp. strains in Vero cells

    Science.gov (United States)

    Silva, Arannadia Barbosa; Duarte, Myrian Morato; Vizzoni, Vinicius Figueiredo; Duré, Ana Íris de Lima; Lopéz, Diego Montenegro; Nogueira, Rita de Maria Seabra; Soares, Carlos Augusto Gomes; Machado-Ferreira, Erik; Gazêta, Gilberto Salles

    2016-01-01

    In Brazil, the spotted fever group (SFG) Rickettsia rickettsii and Rickettsia parkeri related species are the etiological agents of spotted fever rickettsiosis. However, the SFG, Rickettsia rhipicephali, that infects humans, has never been reported. The study of growth dynamics can be useful for understanding the infective and invasive capacity of these pathogens. Here, the growth rates of the Brazilian isolates R. rickettsii str. Taiaçu, R. parkeri str. At#24, and R. rhipicephali HJ#5, were evaluated in Vero cells by quantitative polymerase chain reaction. R. rhipicephali showed different kinetic growth compared to R. rickettsii and R. parkeri. PMID:27508322

  8. Isolation of Candidatus Rickettsia asemboensis from Ctenocephalides Fleas.

    Science.gov (United States)

    Luce-Fedrow, Alison; Maina, Alice N; Otiang, Elkanah; Ade, Fredrick; Omulo, Sylvia; Ogola, Eric; Ochieng, Linus; Njenga, M Kariuki; Richards, Allen L

    2015-04-01

    Candidatus Rickettsia asemboensis was identified molecularly in fleas collected in 2009 from Asembo, Kenya. Multilocus sequence typing using the 17-kD antigen gene, rrs, gltA, ompA, ompB, and sca4 demonstrated that Candidatus R. asemboensis is closely related to Rickettsia felis but distinct enough to be considered for separate species classification. Following this molecular characterization of Candidatus R. asemboensis, the in vitro cultivation of this bacterium was then performed. We used Ctenocephalides canis and Ctenocephalides felis fleas removed from dogs in Kenya to initiate the in vitro isolation of Candidatus R. asemboensis. Successful cultures were obtained using Drosophila melanogaster S2 and Aedes albopictus C6/36 cell lines. Cytological staining and quantitative real-time PCR (qPCR) assays were used to visualize/confirm the culture of the bacteria in both cell lines. Sequencing of fragments of the 17-kD antigen gene, gltA, and ompB genes confirmed the identity of our Candidatus R. asemboensis isolates. To date, we have passaged Candidatus R. asemboensis 12 times through S2 and C6/36 cells, and active and frozen cultures are currently being maintained. This is the first time that a R. felis-like organism has been grown and maintained in culture and is therefore the first time that one of them, Candidatus R. asemboensis, has been characterized beyond molecular typing.

  9. Prevalence and diversity of human pathogenic rickettsiae in urban versus rural habitats, Hungary.

    Science.gov (United States)

    Szekeres, Sándor; Docters van Leeuwen, Arieke; Rigó, Krisztina; Jablonszky, Mónika; Majoros, Gábor; Sprong, Hein; Földvári, Gábor

    2016-02-01

    Tick-borne rickettsioses belong to the important emerging infectious diseases worldwide. We investigated the potential human exposure to rickettsiae by determining their presence in questing ticks collected in an urban park of Budapest and a popular hunting and recreational forest area in southern Hungary. Differences were found in the infectious risk between the two habitats. Rickettsia monacensis and Rickettsia helvetica were identified with sequencing in questing Ixodes ricinus, the only ticks species collected in the city park. Female I. ricinus had a particularly high prevalence of R. helvetica (45%). Tick community was more diverse in the rural habitat with Dermacentor reticulatus ticks having especially high percentage (58%) of Rickettsia raoultii infection. We conclude that despite the distinct eco-epidemiological traits, the risk (hazard and exposure) of acquiring human pathogenic rickettsial infections in both the urban and the rural study sites exists.

  10. A Focus of Dogs and Rickettsia massiliae–Infected Rhipicephalus sanguineus in California

    Science.gov (United States)

    Beeler, Emily; Abramowicz, Kyle F.; Zambrano, Maria L.; Sturgeon, Michele M.; Khalaf, Nada; Hu, Renjie; Dasch, Gregory A.; Eremeeva, Marina E.

    2011-01-01

    A recurrent focus of Rhipicephalus sanguineus infestation was investigated in a suburban area of southern California after reports of suspected Rocky Mountain spotted fever in two dogs on the same property. Abundant quantities of Rh. sanguineus were collected on the property and repeatedly from each dog, and Rickettsia massiliae DNA was detected by polymerase chain reaction (PCR). Whole blood and serum samples from four dogs were tested by using PCR and microimmunofluorescent assay for antibodies against spotted fever group rickettsiae. Serum samples from all four dogs contained antibodies reactive with R. massiliae, R. rhipicephali, R. rickettsii, and 364D Rickettsia but no rickettsial DNA was detected by PCR of blood samples. Serum cross-absorption and Western blot assays implicated R. massiliae as the most likely spotted fever group rickettsiae responsible for seropositivity. To our knowledge, this is the first detection of R. massiliae in ticks in California. PMID:21292893

  11. Orientia, rickettsia, and leptospira pathogens as causes of CNS infections in Laos

    DEFF Research Database (Denmark)

    Dittrich, Sabine; Rattanavong, Sayaphet; Lee, Sue J;

    2015-01-01

    BACKGROUND: Scrub typhus (caused by Orientia tsutsugamushi), murine typhus (caused by Rickettsia typhi), and leptospirosis are common causes of febrile illness in Asia; meningitis and meningoencephalitis are severe complications. However, scarce data exist for the burden of these pathogens......, Neisseria meningitidis, Haemophilus influenzae, S suis) and O tsutsugamushi, Rickettsia typhi/Rickettsia spp, and Leptospira spp infections in blood or cerebrospinal fluid (CSF). We analysed and compared causes and clinical and CSF characteristics between patient groups. FINDINGS: 1051 (95%) of 1112...... patients who presented had CSF available for analysis, of whom 254 (24%) had a CNS infection attributable to a bacterial or fungal pathogen. 90 (35%) of these 254 infections were caused by O tsutsugamushi, R typhi/Rickettsia spp, or Leptospira spp. These pathogens were significantly more frequent than...

  12. Primary isolation of spotted fever group rickettsiae from Amblyomma cooperi collected from Hydrochaeris hydrochaeris in Brazil

    Directory of Open Access Journals (Sweden)

    Elba Regina Sampaio de Lemos

    1996-06-01

    Full Text Available This paper reports the first isolation of a spotted fever group rickettsia from an Amblyomma cooperi ixodid collected from a capybara (Hydrochaeris hydrochaeris in an endemic area of spotted fever in the County of Pedreira, State of São Paulo, Brazil. Isolation was performed in Vero cell culture and submitted to immunofluorescence, using antibody from Rickettsia rickettsii-positive human serum.

  13. Infection of Amblyomma ovale by Rickettsia sp. strain Atlantic rainforest, Colombia.

    Science.gov (United States)

    Londoño, Andrés F; Díaz, Francisco J; Valbuena, Gustavo; Gazi, Michal; Labruna, Marcelo B; Hidalgo, Marylin; Mattar, Salim; Contreras, Verónica; Rodas, Juan D

    2014-10-01

    Our goal was to understand rickettsial spotted fevers' circulation in areas of previous outbreaks reported from 2006 to 2008 in Colombia. We herein present molecular identification and isolation of Rickettsia sp. Atlantic rainforest strain from Amblyomma ovale ticks, a strain shown to be pathogenic to humans. Infected ticks were found on dogs and a rodent in Antioquia and Córdoba Provinces. This is the first report of this rickettsia outside Brazil, which expands its known range considerably.

  14. Detection of Rickettsia amblyommii in association with a tick bite rash.

    Science.gov (United States)

    Billeter, Sarah A; Blanton, Hunter L; Little, Susan E; Levy, Michael G; Breitschwerdt, Edward B

    2007-01-01

    In the summer of 2006, an Amblyomma americanum tick was removed from a woman in central North Carolina, who subsequently developed a rash at the site of tick attachment. When examined by polymerase chain reaction (PCR) for Borrelia, Anaplasma, Ehrlichia, Babesia, Rickettsia, and Bartonella DNA, only the Rickettsia primers generated an amplicon, which was identified as "R. amblyommii" by sequencing. To our knowledge, this is the first case in which R. amblyommii was temporally associated with a rash.

  15. Rickettsia amblyommii infecting Amblyomma sculptum in endemic spotted fever area from southeastern Brazil

    OpenAIRE

    Emília de Carvalho Nunes; Vinicius Figueiredo Vizzoni; Daniel Leal Navarro; Felipe Campos de Melo Iani; Liliane Silva Durães; Erik Daemon; Carlos Augusto Gomes Soares; Gilberto Salles Gazeta

    2015-01-01

    The Rickettsia bacteria include the aetiological agents for the human spotted fever (SF) disease. In the present study, a SF group Rickettsia amblyommii related bacterium was detected in a field collected Amblyomma sculptum (Amblyomma cajennense species complex) tick from a Brazilian SF endemic site in southeastern Brazil, in the municipality of Juiz de Fora, state of Minas Gerais. Genetic analysis based on genes ompA, ompB and htrA showed that the detected strain, named R. amblyo...

  16. Molecular evidence of spotted fever group rickettsiae and Anaplasmataceae from ticks and stray dogs in Bangladesh.

    Science.gov (United States)

    Qiu, Yongjin; Nakao, Ryo; Thu, May June; Akter, Shirin; Alam, Mohammad Zahangir; Kato, Satomi; Katakura, Ken; Sugimoto, Chihiro

    2016-03-01

    Emerging tick-borne diseases (TBDs) are important foci for human and animal health worldwide. However, these diseases are sometimes over looked, especially in countries with limited resources to perform molecular-based surveys. The aim of this study was to detect and characterize spotted fever group (SFG) rickettsiae and Anaplasmataceae in Bangladesh, which are important tick-borne pathogens for humans and animals worldwide. A total of 50 canine blood samples, 15 ticks collected from dogs, and 154 ticks collected from cattle were screened for the presence of SFG rickettsiae and Anaplasmataceae using molecular-based methods such as PCR and real-time PCR. The sequence analysis of the amplified products detected two different genotypes of SFG rickettsiae in ticks from cattle. The genotype detected in Rhipicephalus microplus was closely related to Rickettsia monacensis, while the genotype detected in Haemaphysalis bispinosa was closely related to Rickettsia sp. found in Korea and Japan. Anaplasma bovis was detected in canine blood and ticks (Rhipicephalus sanguineus and H. bispinosa). Unexpectedly, the partial genome sequence of Wolbachia sp., presumably associated with the nematode Dirofilaria immitis, was identified in canine blood. The present study provides the first molecular evidence of SFG rickettsiae and A. bovis in Bangladesh, indicating the possible emergence of previously unrecognized TBDs in this country.

  17. Detection and identification of Rickettsia species in Ixodes tick populations from Estonia.

    Science.gov (United States)

    Katargina, Olga; Geller, Julia; Ivanova, Anna; Värv, Kairi; Tefanova, Valentina; Vene, Sirkka; Lundkvist, Åke; Golovljova, Irina

    2015-09-01

    A total of 1640 ticks collected in different geographical parts of Estonia were screened for the presence of Rickettsia species DNA by real-time PCR. DNA of Rickettsia was detected in 83 out of 1640 questing ticks with an overall prevalence of 5.1%. The majority of the ticks infected by rickettsiae were Ixodes ricinus (74 of 83), while 9 of the 83 positive ticks were Ixodes persulcatus. For rickettsial species identification, a part of the citrate synthase gltA gene was sequenced. The majority of the positive samples were identified as Rickettsia helvetica (81 out of 83) and two of the samples were identified as Rickettsia monacensis and Candidatus R. tarasevichiae, respectively. Genetic characterization based on the partial gltA gene showed that the Estonian sequences within the R. helvetica, R. monacensis and Candidatus R. tarasevichiae species demonstrated 100% similarity with sequences deposited in GenBank, originating from Rickettsia species distributed over large territories from Europe to Asia.

  18. Conditional fitness benefits of the Rickettsia bacterial symbiont in an insect pest.

    Science.gov (United States)

    Cass, Bodil N; Himler, Anna G; Bondy, Elizabeth C; Bergen, Jacquelyn E; Fung, Sierra K; Kelly, Suzanne E; Hunter, Martha S

    2016-01-01

    Inherited bacterial symbionts are common in arthropods and can have strong effects on the biology of their hosts. These effects are often mediated by host ecology. The Rickettsia symbiont can provide strong fitness benefits to its insect host, Bemisia tabaci, under laboratory and field conditions. However, the frequency of the symbiont is heterogeneous among field collection sites across the USA, suggesting that the benefits of the symbiont are contingent on additional factors. In two whitefly genetic lines collected from the same location, we tested the effect of Rickettsia on whitefly survival after heat shock, on whitefly competitiveness at different temperatures, and on whitefly competitiveness at different starting frequencies of Rickettsia. Rickettsia did not provide protection against heat shock nor affect the competitiveness of whiteflies at different temperatures or starting frequencies. However, there was a strong interaction between Rickettsia infection and whitefly genetic line. Performance measures indicated that Rickettsia was associated with significant female bias in both whitefly genetic lines, but in the second whitefly genetic line it conferred no significant fitness benefits nor conferred any competitive advantage to its host over uninfected whiteflies in population cages. These results help to explain other reports of variation in the phenotype of the symbiosis. Furthermore, they demonstrate the complex nature of these close symbiotic associations and the need to consider these interactions in the context of host population structure.

  19. Detection of a novel spotted fever group Rickettsia in the gophertortoise tick.

    Science.gov (United States)

    Zemtsova, Galina E; Gleim, Elizabeth; Yabsley, Michael J; Conner, L Mike; Mann, Tom; Brown, Mary D; Wendland, Lori; Levin, Michael L

    2012-05-01

    The gophertortoise tick, Amblyomma tuberculatum (Marx), is distributed throughout the southeastern United States, and its immature life stages have been reported to occasionally bite humans. Here we report detection of a novel spotted fever group (SFG) Rickettsia in A. tuberculatum ticks collected in the southern United States. Among questing ticks collected in Georgia, 10 pools of larvae were identified as gophertortoise ticks, A. tuberculatum. Each of these samples was positive for SFG Rickettsiae. The restriction fragment-length polymorphism profiles were identical to each other, but distinct from those of other rickettsiae previously found in Amblyomma spp. ticks. Partial genetic characterization of the novel agent was achieved by sequencing the 17 kDa, gltA, ompB, ompA, rpoB, and sca4 genes. Analysis of a concatenated tree of four genes (gltA, ompB, ompA, and sca4) demonstrates close relatedness of the detected Rickettsia to several SFG Rickettsia spp. The identical rickettsial DNA was detected in 50 and 70% of adult A. tuberculatum ticks from Mississippi and Florida, respectively. The results indicate wide distribution of a novel Rickettsia, capability for transovarial transmission, and high prevalence in tested tick populations.

  20. Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan.

    Science.gov (United States)

    Andoh, Masako; Sakata, Akiko; Takano, Ai; Kawabata, Hiroki; Fujita, Hiromi; Une, Yumi; Goka, Koichi; Kishimoto, Toshio; Ando, Shuji

    2015-01-01

    One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the presence of Rickettsia and Ehrlichia spp. genes in ticks associated with reptiles and amphibians originating from outside Japan. Ninety-three ticks representing nine tick species (genera Amblyomma and Hyalomma) were isolated from at least 28 animals spanning 10 species and originating from 12 countries (Ghana, Jordan, Madagascar, Panama, Russia, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Uzbekistan, and Zambia). None of the nine tick species are indigenous in Japan. The genes encoding the common rickettsial 17-kDa antigen, citrate synthase (gltA), and outer membrane protein A (ompA) were positively detected in 45.2% (42/93), 40.9% (38/93), and 23.7% (22/93) of the ticks, respectively, by polymerase chain reaction (PCR). The genes encoding ehrlichial heat shock protein (groEL) and major outer membrane protein (omp-1) were PCR-positive in 7.5% (7/93) and 2.2% (2/93) of the ticks, respectively. The p44 gene, which encodes the Anaplasma outer membrane protein, was not detected. Phylogenetic analysis showed that several of the rickettsial and ehrlichial sequences isolated in this study were highly similar to human pathogen genes, including agents not previously detected in Japan. These data demonstrate the global transportation of pathogenic Rickettsia and Ehrlichia through reptile- and amphibian-associated ticks. These imported animals have potential to transfer pathogens into human life. These results highlight the need to control the international transportation of known and

  1. Detection of Rickettsia and Ehrlichia spp. in Ticks Associated with Exotic Reptiles and Amphibians Imported into Japan.

    Directory of Open Access Journals (Sweden)

    Masako Andoh

    Full Text Available One of the major routes of transmission of rickettsial and ehrlichial diseases is via ticks that infest numerous host species, including humans. Besides mammals, reptiles and amphibians also carry ticks that may harbor Rickettsia and Ehrlichia strains that are pathogenic to humans. Furthermore, reptiles and amphibians are exempt from quarantine in Japan, thus facilitating the entry of parasites and pathogens to the country through import. Accordingly, in the current study, we examined the presence of Rickettsia and Ehrlichia spp. genes in ticks associated with reptiles and amphibians originating from outside Japan. Ninety-three ticks representing nine tick species (genera Amblyomma and Hyalomma were isolated from at least 28 animals spanning 10 species and originating from 12 countries (Ghana, Jordan, Madagascar, Panama, Russia, Sri Lanka, Sudan, Suriname, Tanzania, Togo, Uzbekistan, and Zambia. None of the nine tick species are indigenous in Japan. The genes encoding the common rickettsial 17-kDa antigen, citrate synthase (gltA, and outer membrane protein A (ompA were positively detected in 45.2% (42/93, 40.9% (38/93, and 23.7% (22/93 of the ticks, respectively, by polymerase chain reaction (PCR. The genes encoding ehrlichial heat shock protein (groEL and major outer membrane protein (omp-1 were PCR-positive in 7.5% (7/93 and 2.2% (2/93 of the ticks, respectively. The p44 gene, which encodes the Anaplasma outer membrane protein, was not detected. Phylogenetic analysis showed that several of the rickettsial and ehrlichial sequences isolated in this study were highly similar to human pathogen genes, including agents not previously detected in Japan. These data demonstrate the global transportation of pathogenic Rickettsia and Ehrlichia through reptile- and amphibian-associated ticks. These imported animals have potential to transfer pathogens into human life. These results highlight the need to control the international transportation of known

  2. Ticks and spotted fever group rickettsiae of southeastern Virginia.

    Science.gov (United States)

    Nadolny, Robyn M; Wright, Chelsea L; Sonenshine, Daniel E; Hynes, Wayne L; Gaff, Holly D

    2014-02-01

    The incidence of tick-borne rickettsial disease in the southeastern United States has been rising steadily through the past decade, and the range expansions of tick species and tick-borne infectious agents, new and old, has resulted in an unprecedented mix of vectors and pathogens. The results of an ongoing 4-year surveillance project describe the relative abundance of questing tick populations in southeastern Virginia. Since 2009, more than 66,000 questing ticks of 7 species have been collected from vegetation in a variety of habitats, with Amblyomma americanum constituting over 95% of ticks collected. Other species represented included Ixodes scapularis, Dermacentor variabilis, Amblyomma maculatum, Ixodes affinis, Haemaphysalis leporispalustris, and Ixodes brunneus. We found that 26.9-54.9% of A. americanum ticks tested were positive for Rickettsia amblyommii, a non-pathogenic symbiont of this tick species. We also found no evidence of R. rickettsii in D. variabilis ticks, although they did show low infection rates of R. montanensis (1.5-2.0%). Rickettsia parkeri and Candidatus R. andeanae were found in 41.8-55.7% and 0-1.5% A. maculatum ticks, respectively. The rate of R. parkeri in A. maculatum ticks is among the highest in the literature and has increased in the 2 years since R. parkeri and A. maculatum were first reported in southeastern Virginia. We conclude that tick populations in southeastern Virginia have recently undergone dramatic changes in species and abundance and that these populations support a variety of rickettsial agents with the potential for increased risk to human health.

  3. Molecular detection of Rickettsia, Borrelia, and Babesia species in Ixodes ricinus sampled in northeastern, central, and insular areas of Italy.

    Science.gov (United States)

    Castro, Lyda R; Gabrielli, Simona; Iori, Albertina; Cancrini, Gabriella

    2015-07-01

    The aim of the present study was to provide insight into the diversity of tick-borne pathogens circulating in Italy, carried/transmitted by Ixodes ricinus, one of the most abundant tick species in the country. A total of 447 specimens sampled in five areas of northeastern, central and insular Italy were analysed by polymerase chain reaction and sequencing for the presence of rickettsiae, borreliae and babesiae. Several rickettsial species of the spotted fever group of zoonotic concern and other zoonotic pathogens were found, such as Borrelia burgdorferi s.s., Borrelia afzelii, Borrelia garinii, and Babesia venatorum. These findings confirm a wide distribution of tick-borne bacterial and protozoan species in Italy, and highlight the sanitary importance of I. ricinus, often recorded as feeding on humans.

  4. INFECTION BY Rickettsia felis IN OPOSSUMS (Didelphis sp. FROM YUCATAN, MEXICO

    Directory of Open Access Journals (Sweden)

    Gaspar PENICHE-LARA

    2016-01-01

    Full Text Available Rickettsia felis is an emergent pathogen and the causative agent of a typhus-like rickettsiosis in the Americas. Its transmission cycle involves fleas as biological vectors (mainly Ctenocephalides felis and multiple domestic and synanthropic mammal hosts. Nonetheless, the role of mammals in the cycle of R. felis is not well understood and many efforts are ongoing in different countries of America to clarify it. The present study describes for the first time in Mexico the infection of two species of opossum (Didelphis virginiana and D. marsupialis by R. felis. A diagnosis was carried out from blood samples by molecular methods through the gltAand 17 kDa genes and sequence determination. Eighty-seven opossum samples were analyzed and 28 were found to be infected (32.1% from five out of the six studied localities of Yucatan. These findings enable recognition of the potential epidemiological implications for public health of the presence of infected synanthropic Didelphis in households.

  5. Nuclear Magnetic Resonance (NMR) as a tool for the study of the metabolism of Rickettsia slovaca.

    Science.gov (United States)

    García-Álvarez, Lara; Busto, Jesús H; Peregrina, Jesús M; Santibáñez, Sonia; Portillo, Aránzazu; Avenoza, Alberto; Oteo, José A

    2015-01-01

    Rickettsial infections are caused by intracellular bacteria. They do not grow in standard culture media so there are limitations in routine practice to study their metabolism. Nuclear Magnetic Resonance (NMR) spectroscopy is used for identification of metabolites in biological samples. Vero cells infected with Rickettsia slovaca as well as uninfected cells were monitored by (1)H NMR showing the presence of ethanol and lactic acid. As no differences were observed, labeled compounds were added into cultures. When D-[1-13C]glucose was monitored by (13)C NMR no differences among infected and uninfected cells were observed in metabolic profiles. Glucose was transformed into ethanol in all cultures. Monitored experiments carried out with [2-13C]glycine showed differences between infected and uninfected cell cultures spectra. Glycine was partially transformed into serine, but the amount of the serine formed was larger in those infected. Moreover, L-[2-13C]leucine, L-[1-13C]isoleucine and L-[15N]tyrosine were evaluated. No differences among infected and uninfected cells were observed in the metabolic profiles when tyrosine and leucine were monitored. The amino acid L-[1-13C]isoleucine exhibited different metabolism in presence of the R. slovaca, showing a promising behavior as biomarker. In this work we focused on finding one or more compounds that could be metabolized specifically by R. slovaca and could be used as an indicator of its activity.

  6. Development of three quantitative real-time PCR assays for the detection of Rickettsia raoultii, Rickettsia slovaca, and Rickettsia aeschlimannii and their validation with ticks from the country of Georgia and the Republic of Azerbaijan.

    Science.gov (United States)

    Jiang, Ju; You, Brian J; Liu, Evan; Apte, Anisha; Yarina, Tamasin R; Myers, Todd E; Lee, John S; Francesconi, Stephen C; O'Guinn, Monica L; Tsertsvadze, Nikoloz; Vephkhvadze, Nino; Babuadze, Giorgi; Sidamonidze, Ketevan; Kokhreidze, Maka; Donduashvili, Marina; Onashvili, Tinatin; Ismayilov, Afrail; Agayev, Nigar; Aliyev, Mubariz; Muttalibov, Nizam; Richards, Allen L

    2012-12-01

    A previous surveillance study of human pathogens within ticks collected in the country of Georgia showed a relatively high infection rate for Rickettsia raoultii, R. slovaca, and R. aeschlimannii. These 3 spotted fever group rickettsiae are human pathogens: R. raoultii and R. slovaca cause tick-borne lymphadenopathy (TIBOLA), and R. aeschlimannii causes an infection characterized by fever and maculopapular rash. Three quantitative real-time polymerase chain reaction (qPCR) assays, Rraoul, Rslov, and Raesch were developed and optimized to detect R. raoultii, R. slovaca, and R. aeschlimannii, respectively, by targeting fragments of the outer membrane protein B gene (ompB) using species-specific molecular beacon or TaqMan probes. The 3 qPCR assays showed 100% specificity when tested against a rickettsiae DNA panel (n=20) and a bacteria DNA panel (n=12). The limit of detection was found to be at least 3 copies per reaction for all assays. Validation of the assays using previously investigated tick nucleic acid preparations, which included Rickettsia-free tick samples, tick samples that contain R. raoultii, R. slovaca, R. aeschlimannii, and other Rickettsia spp., gave 100% sensitivity for all 3 qPCR assays. In addition, a total of 65 tick nucleic acid preparations (representing 259 individual ticks) collected from the country of Georgia and the Republic of Azerbaijan in 2009 was tested using the 3 qPCR assays. R. raoultii, R. slovaca, and R. aeschlimannii were not detected in any ticks (n=31) from the Republic of Azerbaijan, but in the ticks from the country of Georgia (n=228) the minimal infection rate for R. raoultii and R. slovaca in Dermacentor marginatus was 10% and 4%, respectively, and for R. aeschlimannii in Haemaphysalis sulcata and Hyalomma spp. it was 1.9% and 20%, respectively.

  7. High prevalence of "Candidatus Rickettsia andeanae" and apparent exclusion of Rickettsia parkeri in adult Amblyomma maculatum (Acari: Ixodidae) from Kansas and Oklahoma.

    Science.gov (United States)

    Paddock, Christopher D; Denison, Amy M; Dryden, Michael W; Noden, Bruce H; Lash, R Ryan; Abdelghani, Sarah S; Evans, Anna E; Kelly, Aubree R; Hecht, Joy A; Karpathy, Sandor E; Ganta, Roman R; Little, Susan E

    2015-04-01

    Amblyomma maculatum (the Gulf Coast tick), an aggressive, human-biting, Nearctic and Neotropical tick, is the principal vector of Rickettsia parkeri in the United States. This pathogenic spotted fever group Rickettsia species has been identified in 8-52% of questing adult Gulf Coast ticks in the southeastern United States. To our knowledge, R. parkeri has not been reported previously from adult specimens of A. maculatum collected in Kansas or Oklahoma. A total of 216 adult A. maculatum ticks were collected from 18 counties in Kansas and Oklahoma during 2011-2014 and evaluated by molecular methods for evidence of infection with R. parkeri. No infections with this agent were identified; however, 47% of 94 ticks collected from Kansas and 73% of 122 ticks from Oklahoma were infected with "Candidatus Rickettsia andeanae" a spotted fever group Rickettsia species of undetermined pathogenicity. These preliminary data suggest that "Ca. R. andeanae" is well-adapted to survival in populations of A. maculatum in Kansas and Oklahoma, and that its ubiquity in Gulf Coast ticks in these states may effectively exclude R. parkeri from their shared arthropod host, which could diminish markedly or preclude entirely the occurrence of R. parkeri rickettsiosis in this region of the United States.

  8. Analysis of Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    孙淑珍

    2004-01-01

    Chapter Ⅰ Introduction  Sitting in the rocking chair,Carrie dreams her future.This is the deep impression the novel"Sister Carrie"gives us,which is written by Theodore Dreiser(1871-1945),the great American realism writer.  ……

  9. Pathogenic potential of a Costa Rican strain of 'Candidatus Rickettsia amblyommii' in guinea pigs (Cavia porcellus) and protective immunity against Rickettsia rickettsii.

    Science.gov (United States)

    Rivas, Juan J; Moreira-Soto, Andrés; Alvarado, Gilberth; Taylor, Lizeth; Calderón-Arguedas, Olger; Hun, Laya; Corrales-Aguilar, Eugenia; Morales, Juan Alberto; Troyo, Adriana

    2015-09-01

    'Candidatus Rickettsia amblyommii' is a spotted fever group rickettsia that is not considered pathogenic, although there is serologic evidence of possible infection in animals and humans. The aim of this study was to evaluate the pathogenic potential of a Costa Rican strain of 'Candidatus R. amblyommii' in guinea pigs and determine its capacity to generate protective immunity against a subsequent infection with a local strain of Rickettsia rickettsii isolated from a human case. Six guinea pigs were inoculated with 'Candidatus R. amblyommii' strain 9-CC-3-1 and two controls with cell culture medium. Health status was evaluated, and necropsies were executed at days 2, 4, and 13. Blood and tissues were processed by PCR to detect the gltA gene, and end titers of anti-'Candidatus R. amblyommii' IgG were determined by indirect immunofluorescence. To evaluate protective immunity, another 5 guinea pigs were infected with 'Candidatus R. amblyommii' (IGPs). After 4 weeks, these 5 IGPs and 3 controls (CGPs) were inoculated with pathogenic R. rickettsii. Clinical signs and titers of anti-Rickettsia IgG were determined. IgG titers reached 1:512 at day 13 post-infection with 'Candidatus R. amblyommii'. On day 2 after inoculation, two guinea pigs had enlarged testicles and 'Candidatus R. amblyommii' DNA was detected in testicles. Histopathology confirmed piogranulomatous orchitis with perivascular inflammatory infiltrate in the epididymis. In the protective immunity assay, anti-Rickettsia IgG end titers after R. rickettsii infection were lower in IGPs than in CGPs. IGPs exhibited only transient fever, while CGP showed signs of severe disease and mortality. R. rickettsii was detected in testicles and blood of CGPs. Results show that the strain 9-CC-3-1 of 'Candidatus R. amblyommii' was able to generate pathology and an antibody response in guinea pigs. Moreover, its capacity to generate protective immunity against R. rickettsii may modulate the epidemiology and severity of Rocky

  10. High prevalence of Rickettsia typhi and Bartonella species in rats and fleas, Kisangani, Democratic Republic of the Congo

    NARCIS (Netherlands)

    Laudisoit, A.; Falay, D.; Amundala, N.; de Bellock, J.G.; van Houtte, N.; Breno, M.; Verheven, E.; Wilschut, Liesbeth; Parola, P.; Raoult, D.; C., Socolovschi

    2014-01-01

    The prevalence and identity of Rickettsia and Bartonella in urban rat and flea populations were evaluated in Kisangani, Democratic Republic of the Congo (DRC) by molecular tools. An overall prevalence of 17% Bartonella species and 13% Rickettsia typhi, the agent of murine typhus, was found in the co

  11. Detection of spotted fever group Rickettsiae in ticks from Zhejiang Province, China.

    Science.gov (United States)

    Sun, Jimin; Lin, Junfen; Gong, Zhenyu; Chang, Yue; Ye, Xiaodong; Gu, Shiping; Pang, Weilong; Wang, Chengwei; Zheng, Xiaohua; Hou, Juan; Ling, Feng; Shi, Xuguang; Jiang, Jianmin; Chen, Zhiping; Lv, Huakun; Chai, Chengliang

    2015-03-01

    Tick species distribution and prevalence of spotted fever group Rickettsiae (SFGR) in ticks were investigated in Zhejiang Province, China in 2010 and 2011. PCR was used to detect SFGR and positive amplicons were sequenced, compared to published sequences and phylogenic analysis was performed using MEGA 4.0. A total of 292 adult ticks of ten species were captured and 7.5 % (22/292) of the ticks were PCR-positive for SFG Rickettsia. The PCR-positive rates were 5.5 % (6/110) for Haemaphysalis longicornis, 3.6 % (1/28) for Amblyomma testudinarium and 16 % (15/94) for Ixodes sinensis, respectively. Phylogenetic analyses of gltA genes detected in ticks indicated that there are two dominating groups of SFGR. Sequences of group one were closely related to Rickettsia monacensis, whereas sequences of group two were closest related to Rickettsia heilongjiangensis and Rickettsia japonica, which are human pathogens. Our findings underline the importance of these ticks in public health surveillance in Zhejiang Province, China.

  12. Rickettsia parkeri infecting free-living Amblyomma triste ticks in the Brazilian Pantanal.

    Science.gov (United States)

    Melo, Andréia L T; Alves, Alvair S; Nieri-Bastos, Fernanda A; Martins, Thiago F; Witter, Rute; Pacheco, Thábata A; Soares, Herbert S; Marcili, Arlei; Chitarra, Cristiane S; Dutra, Valéria; Nakazato, Luciano; Pacheco, Richard C; Labruna, Marcelo B; Aguiar, Daniel M

    2015-04-01

    The present study evaluated the infection of rickettsiae in 151 Rhipicephalus sanguineus, 59 Amblyomma ovale, 166 Amblyomma triste, one Amblyomma dissimile and four Amblyomma dubitatum ticks collected in the municipality of Poconé, State of Mato Grosso, within the Pantanal biome of Brazil. Ticks were individually processed by the hemolymph test with Gimenez staining, isolation of rickettsia in Vero cell culture by the shell vial technique, and polymerase chain reaction (PCR) targeting the citrate synthase rickettsial gene. Through the shell vial technique, rickettsiae were successfully isolated and established in Vero cell culture from one free-living A. triste female tick, which previously showed to contain Rickettsia-like organisms by the hemolymph test. Molecular characterization of the rickettsial isolate was achieved through DNA partial sequences of three rickettsial genes (gltA, ompA, ompB), which showed to be all 100% identical to Rickettsia parkeri. After testing all ticks by PCR, the frequency of R. parkeri infection was 7.23% (12/166) in A. triste adult ticks. The remaining ticks were negative by PCR. This is the first report of in vitro isolation of R. parkeri in the Pantanal biome, confirming the occurrence of this emerging rickettsial pathogen in this natural area of South America.

  13. Molecular characterization of 'Candidatus Rickettsia vini' in Ixodes arboricola from the Czech Republic and Slovakia.

    Science.gov (United States)

    Novakova, Marketa; Bulkova, Alexandra; Costa, Francisco B; Kristin, Anton; Krist, Milos; Krause, Frantisek; Liznarova, Eva; Labruna, Marcelo B; Literak, Ivan

    2015-04-01

    The aim of this study was to analyze the prevalence of rickettsiae in the tree-hole tick Ixodes arboricola in the Czech Republic and Slovakia. During May to September of 2009 and 2013, bird boxes belonging to three different areas were screened for ticks. In total, 454 nestlings and 109 nests of 10 hole-breeding bird species were examined. Ticks were found on Ficedula albicollis, Parus major, Cyanistes caeruleus and Sitta europaea and/or in their nests. In total, 166 ticks (17 nymphs, 10 males and 139 females) were found at 3 areas (arithmetic mean±standard error: 55.3±45.9). All ticks were tested for the presence of Rickettsia species by polymerase chain reaction targeting the rickettsial genes gltA, ompA, ompB and htrA and amplicon sequencing. All individuals except 3 nymphs were infected with 'Candidatus Rickettsia vini'. Multilocus sequence typing showed closest proximity to Rickettsia japonica and Rickettsia heilongjiangensis cluster. The presence of 'Ca. R. vini' is reported for the first time in Slovakia.

  14. The Facultative Symbiont Rickettsia Protects an Invasive Whitefly against Entomopathogenic Pseudomonas syringae Strains.

    Science.gov (United States)

    Hendry, Tory A; Hunter, Martha S; Baltrus, David A

    2014-12-01

    Facultative endosymbionts can benefit insect hosts in a variety of ways, including context-dependent roles, such as providing defense against pathogens. The role of some symbionts in defense may be overlooked, however, when pathogen infection is transient, sporadic, or asymptomatic. The facultative endosymbiont Rickettsia increases the fitness of the sweet potato whitefly (Bemisia tabaci) in some populations through mechanisms that are not yet understood. In this study, we investigated the role of Rickettsia in mediating the interaction between the sweet potato whitefly and Pseudomonas syringae, a common environmental bacterium, some strains of which are pathogenic to aphids. Our results show that P. syringae multiplies within whiteflies, leading to host death, and that whiteflies infected with Rickettsia show a decreased rate of death due to P. syringae. Experiments using plants coated with P. syringae confirmed that whiteflies can acquire the bacteria at a low rate while feeding, leading to increased mortality, particularly when the whiteflies are not infected with Rickettsia. These results suggest that P. syringae may affect whitefly populations in nature and that Rickettsia can ameliorate this effect. This study highlights the possible importance of interactions among opportunistic environmental pathogens and endosymbionts of insects.

  15. Spotted fever group rickettsiae in Amblyomma ticks likely to infest humans in rural areas from northwestern Argentina.

    Science.gov (United States)

    Saracho Bottero, María N; Tarragona, Evelina L; Nava, Santiago

    2015-01-01

    This work was performed to detect Rickettsia species of the spotted fever group in Amblyomma ticks likely to infest humans in rural areas from northwestern Argentina. Free-living ticks were collected and determined as Amblyomma tigrinum, Amblyomma neumanni and Amblyomma tonelliae. Rickettsia infection was determined by polymerase chain reactions which amplify fragments of the rickettsial genes gltA and ompA. A high frequency (35/44, 79.5%) of Candidatus "Rickettsia andeanae" was observed in A. tigrinum ticks, and Candidatus "Rickettsia amblyommii" was found in three out of 14 nymphs of A. neumanni. All 14 Amblyomma tonelliae ticks were negative for rikettsiae. The infection with spotted fever group rickettsiae in ticks aggressive for humans reveals the potential risk of exposure to tick-borne pathogens of people inhabiting rural areas of northwestern Argentina.

  16. Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil.

    Science.gov (United States)

    Araes-Santos, Ana Isabel; Moraes-Filho, Jonas; Peixoto, Renata M; Spolidorio, Mariana G; Azevedo, Sérgio S; Costa, Mateus M; Labruna, Marcelo B; Horta, Mauricio C

    2015-11-01

    This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables "to reside in Petrolina" and "presence of ectoparasites." Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp.

  17. [Microbiological diagnosis of emerging bacterial pathogens: Anaplasma, Bartonella, Rickettsia, and Tropheryma whipplei].

    Science.gov (United States)

    Blanco, José Ramón; Jado, Isabel; Marín, Mercedes; Sanfeliu, Isabel; Portillo, Aránzazu; Anda, Pedro; Pons, Immaculada; Oteo, José Antonio

    2008-11-01

    Ehrlichia/Anaplasma, Bartonella, Rickettsia and Tropheryma whipplei (formerly called whippelii) are fastidious bacterial organisms, considered the causative agents of potentially severe emerging and re-emerging diseases with repercussions on public health. The recent availability of advanced molecular biology and cell culture techniques has led to the implication of many of these species in human pathologies. These issues are extensively covered in number 27 of the SEIMC microbiological procedure: Diagnóstico microbiológico de las infecciones por patógenos bacterianos emergentes: Anaplasma, Bartonella, Rickettsia y Tropheryma whippelii (Microbiological diagnosis of Anaplasma, Bartonella, Rickettsia and Tropheryma whippelii infections) (2nd ed., 2007) (www.seimc.org/documentos/protocolos/microbiologia/).

  18. Investigations on Rickettsia in Ticks at the Sino-Russian and Sino-Mongolian Borders, China.

    Science.gov (United States)

    Liu, Lijuan; Chen, Qian; Yang, Yu; Wang, Jiancheng; Cao, Xiaomei; Zhang, Sheng; Li, Hong; Hou, Yong; Wang, Fuxiang; Xu, Baoliang

    2015-12-01

    To describe the prevalence of Rickettsia in ticks at the Sino-Russian and Sino-Mongolian borders, a total of 292 ticks were collected and tested by conventional PCR assays. The prevalence of Rickettsia was 53.4%, and phylogenetic analysis showed that they belonged to R. raoultii species after alignment for the ompA, ompB, and gltA genes, respectively. Coxiella burnetii DNA was detected for 14%, and no Ehrlichia, Borrelia burgdorferi, and Babesia species were found. Co-infection of two pathogens was 9.9%, and no co-infection with three or more pathogens was found. This study suggested Rickettsia was the most common pathogen in the ticks and co-infection was found. The findings might be helpful to provide advice on the prevention and control of tick-borne disease potential for tourists and residents.

  19. Seroprevalence of Rickettsia bellii and Rickettsia felis in dogs, São José dos Pinhais, State of Paraná, Brazil Soroprevalência de Rickettsia bellii e Rickettsia felis em cães, São José dos Pinhais, Paraná, Brasil

    Directory of Open Access Journals (Sweden)

    Fernanda Silva Fortes

    2010-12-01

    Full Text Available Brazilian spotted fever (BSF is a vector-borne zoonosis caused by Rickettsia rickettsii bacteria. Dogs can be host sentinels for this bacterium. The aim of the study was to determine the presence of antibodies against Rickettsia spp. in dogs from the city of São José dos Pinhais, State of Paraná, Southern Brazil, where a human case of BSF was first reported in the state. Between February 2006 and July 2007, serum samples from 364 dogs were collected and tested at 1:64 dilutions by indirect immunofluorescence assay (IFA against R. rickettsii and R. parkeri. All sera that reacted at least to one of Rickettsia species were tested against the six main Rickettsia species identified in Brazil: R. rickettsii, R. parkeri, R. bellii, R. rhipicephali, R. amblyommii and R. felis. Sixteen samples (4.4% reacted to at least one Rickettsia species. Among positive animals, two dogs (15.5% showed suggestive titers for R. bellii exposure. One sample had a homologous reaction to R. felis, a confirmed human pathogen. Although Rickettsia spp. circulation in dogs in the area studied may be considered at low prevalence, suggesting low risk of human infection, the present data demonstrate for the first time the exposure of dogs to R. bellii and R. felis in Southern Brazil.A febre maculosa brasileira (FMB é uma zoonose veiculada por carrapatos e causada pela bactéria Rickettsia rickettsii, podendo os cães ser hospedeiros sentinelas para essa bactéria. O objetivo do estudo foi determinar a presença de anticorpos contra Rickettsia spp. em cães de São José dos Pinhais, estado do Paraná, Sul do Brasil. Entre fevereiro de 2006 e julho de 2007, amostras séricas de 364 cães foram coletadas e testadas na diluição de 1:64 por Reação de Imunofluorescência Indireta (RIFI contra R. rickettsii e R. parkeri. Todos os soros reagentes para pelo menos uma espécie de Rickettsia foram testados contra as seis principais espécies de Rickettsia identificadas no Brasil: R

  20. Rickettsia africae in Hyalomma dromedarii ticks from sub-Saharan Algeria.

    Science.gov (United States)

    Kernif, Tahar; Djerbouh, Amel; Mediannikov, Oleg; Ayach, Bouhous; Rolain, Jean-Marc; Raoult, Didier; Parola, Philippe; Bitam, Idir

    2012-12-01

    Spotted fever group (SFG) rickettsioses are caused by obligate, intracellular Gram-negative bacteria of the genus Rickettsia. In recent years, several species and subspecies of rickettsias have been identified as emerging pathogens throughout the world, including sub-Saharan Africa. We report here the detection of Rickettsia africae, the agent responsible for African tick-bite fever, by amplification of fragments of gltA and ompA genes and multi-spacer typing from Hyalomma dromedarii ticks collected from the camel Camelus dromedarius in the Adrar and Béchar region (sub-Saharan Algeria). To date, R. africae has been associated mainly with Amblyomma spp. The role of H. dromedarii in the epidemiology of R. africae requires further investigation.

  1. "Rickettsia amblyommii" induces cross protection against lethal Rocky Mountain spotted fever in a guinea pig model.

    Science.gov (United States)

    Blanton, Lucas S; Mendell, Nicole L; Walker, David H; Bouyer, Donald H

    2014-08-01

    Rocky Mountain spotted fever (RMSF) is a severe illness caused by Rickettsia rickettsii for which there is no available vaccine. We hypothesize that exposure to the highly prevalent, relatively nonpathogenic "Rickettsia amblyommii" protects against R. rickettsii challenge. To test this hypothesis, guinea pigs were inoculated with "R. amblyommii." After inoculation, the animals showed no signs of illness. When later challenged with lethal doses of R. rickettsii, those previously exposed to "R. amblyommii" remained well, whereas unimmunized controls developed severe illness and died. We conclude that "R. amblyommii" induces an immune response that protects from illness and death in the guinea pig model of RMSF. These results provide a basis for exploring the use of low-virulence rickettsiae as a platform to develop live attenuated vaccine candidates to prevent severe rickettsioses.

  2. RickA expression is not sufficient to promote actin-based motility of Rickettsia raoultii.

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    Premanand Balraj

    Full Text Available BACKGROUND: Rickettsia raoultii is a novel Rickettsia species recently isolated from Dermacentor ticks and classified within the spotted fever group (SFG. The inability of R. raoultii to spread within L929 cells suggests that this bacterium is unable to polymerize host cell actin, a property exhibited by all SFG rickettsiae except R. peacocki. This result led us to investigate if RickA, the protein thought to generate actin nucleation, was expressed within this rickettsia species. METHODOLOGY/PRINCIPAL FINDINGS: Amplification and sequencing of R. raoultii rickA showed that this gene encoded a putative 565 amino acid protein highly homologous to those found in other rickettsiae. Using immunofluorescence assays, we determined that the motility pattern (i.e. microcolonies or cell-to-cell spreading of R. raoultii was different depending on the host cell line in which the bacteria replicated. In contrast, under the same experimental conditions, R. conorii shares the same phenotype both in L929 and in Vero cells. Transmission electron microscopy analysis of infected cells showed that non-motile bacteria were free in the cytosol instead of enclosed in a vacuole. Moreover, western-blot analysis demonstrated that the defect of R. raoultii actin-based motility within L929 cells was not related to lower expression of RickA. CONCLUSION/SIGNIFICANCE: These results, together with previously published data about R. typhi, strongly suggest that another factor, apart from RickA, may be involved with be responsible for actin-based motility in bacteria from the Rickettsia genus.

  3. Differences in Intracellular Fate of Two Spotted Fever Group Rickettsia in Macrophage-Like Cells

    Science.gov (United States)

    Curto, Pedro; Simões, Isaura; Riley, Sean P.; Martinez, Juan J.

    2016-01-01

    Spotted fever group (SFG) rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (Rickettsia conorii) and Rocky Mountain spotted fever (Rickettsia rickettsii). Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickettsial diseases. These studies raise the hypothesis that the role of macrophages in rickettsial pathogenesis may have been underappreciated. Herein, we evaluated the ability of two SFG rickettsial species, R. conorii (a recognized human pathogen) and Rickettsia montanensis (a non-virulent member of SFG) to proliferate in THP-1 macrophage-like cells, or within non-phagocytic cell lines. Our results demonstrate that R. conorii was able to survive and proliferate in both phagocytic and epithelial cells in vitro. In contrast, R. montanensis was able to grow in non-phagocytic cells, but was drastically compromised in the ability to proliferate within both undifferentiated and PMA-differentiated THP-1 cells. Interestingly, association assays revealed that R. montanensis was defective in binding to THP-1-derived macrophages; however, the invasion of the bacteria that are able to adhere did not appear to be affected. We have also demonstrated that R. montanensis which entered into THP-1-derived macrophages were rapidly destroyed and partially co-localized with LAMP-2 and cathepsin D, two markers of lysosomal compartments. In contrast, R. conorii was present as intact bacteria and free in the cytoplasm in both cell types. These findings suggest that a phenotypic difference between a non-pathogenic and a pathogenic SFG member lies in their respective ability to proliferate in macrophage-like cells, and may provide an explanation as to why certain SFG rickettsial species are not associated

  4. Tick cell culture isolation and growth of Rickettsia raoultii from Dutch Dermacentor reticulatus ticks.

    Science.gov (United States)

    Alberdi, M Pilar; Nijhof, Ard M; Jongejan, Frans; Bell-Sakyi, Lesley

    2012-12-01

    Tick cell lines play an important role in research on ticks and tick-borne pathogenic and symbiotic microorganisms. In an attempt to derive continuous Dermacentor reticulatus cell lines, embryo-derived primary cell cultures were set up from eggs laid by field ticks originally collected as unfed adults in The Netherlands and maintained for up to 16 months. After several months, it became evident that cells in the primary cultures were infected with a Rickettsia-like intracellular organism. Supernatant medium containing some D. reticulatus cells was inoculated into cultures of 2 Rhipicephalus (Boophilus) microplus cell lines, BME/CTVM2 and BME/CTVM23, where abundant growth of the bacteria occurred intracellularly on transfer to both cell lines. Bacterial growth was monitored by light (live, inverted microscope, Giemsa-stained cytocentrifuge smears) and transmission electron microscopy revealing heavy infection with typical intracytoplasmic Rickettsia-like bacteria, not present in uninfected cultures. DNA was extracted from bacteria-infected and uninfected control cultures, and primers specific for Rickettsia 16S rRNA, ompB, and sca4 genes were used to generate PCR products that were subsequently sequenced. D. reticulatus primary cultures and both infected tick cell lines were positive for all 3 Rickettsia genes. Sequencing of PCR products revealed 99-100% identity with published Rickettsia raoultii sequences. The R. raoultii also grew abundantly in the D. nitens cell line ANE58, poorly in the D. albipictus cell line DALBE3, and not at all in the D. andersoni cell line DAE15. In conclusion, primary tick cell cultures and cell lines are useful systems for isolation and propagation of fastidious tick-borne microorganisms. In vitro isolation of R. raoultii from Dutch D. reticulatus confirms previous PCR-based detection in field ticks, and presence of the bacteria in the tick eggs used to initiate the primary cultures confirms that transovarial transmission of this

  5. Amblyomma maculatum Feeding Augments Rickettsia parkeri Infection in a Rhesus Macaque Model: A Pilot Study.

    Science.gov (United States)

    Banajee, Kaikhushroo H; Embers, Monica E; Langohr, Ingeborg M; Doyle, Lara A; Hasenkampf, Nicole R; Macaluso, Kevin R

    2015-01-01

    Rickettsia parkeri is an emerging eschar-causing human pathogen in the spotted fever group of Rickettsia and is transmitted by the Gulf coast tick, Amblyomma maculatum. Tick saliva has been shown to alter both the cellular and humoral components of the innate and adaptive immune systems. However, the effect of this immunomodulation on Rickettsia transmission and pathology in an immunocompetent vertebrate host has not been fully examined. We hypothesize that, by modifying the host immune response, tick feeding enhances infection and pathology of pathogenic spotted fever group Rickettsia sp. In order to assess this interaction in vivo, a pilot study was conducted using five rhesus macaques that were divided into three groups. One group was intradermally inoculated with low passage R. parkeri (Portsmouth strain) alone (n = 2) and another group was inoculated during infestation by adult, R. parkeri-free A. maculatum (n = 2). The final macaque was infested with ticks alone (tick feeding control group). Blood, lymph node and skin biopsies were collected at several time points post-inoculation/infestation to assess pathology and quantify rickettsial DNA. As opposed to the tick-only animal, all Rickettsia-inoculated macaques developed inflammatory leukograms, elevated C-reactive protein concentrations, and elevated TH1 (interferon-γ, interleukin-15) and acute phase inflammatory cytokines (interleukin-6) post-inoculation, with greater neutrophilia and interleukin-6 concentrations in the tick plus R. parkeri group. While eschars formed at all R. parkeri inoculation sites, larger and slower healing eschars were observed in the tick feeding plus R. parkeri group. Furthermore, dissemination of R. parkeri to draining lymph nodes early in infection and increased persistence at the inoculation site were observed in the tick plus R. parkeri group. This study indicates that rhesus macaques can be used to model R. parkeri rickettsiosis, and suggests that immunomodulatory factors

  6. Molecular evidence of Rickettsia felis infection in dogs from northern territory, Australia

    Directory of Open Access Journals (Sweden)

    Rees Robert L

    2011-10-01

    Full Text Available Abstract The prevalence of spotted fever group rickettsial infection in dogs from a remote indigenous community in the Northern Territory (NT was determined using molecular tools. Blood samples collected from 130 dogs in the community of Maningrida were subjected to a spotted fever group (SFG-specific PCR targeting the ompB gene followed by a Rickettsia felis-specific PCR targeting the gltA gene of R. felis. Rickettsia felis ompB and gltA genes were amplified from the blood of 3 dogs. This study is the first report of R. felis infection in indigenous community dogs in NT.

  7. Survey for hantaviruses, tick-borne encephalitis virus, and Rickettsia spp. in small rodents in Croatia.

    Science.gov (United States)

    Svoboda, Petra; Dobler, Gerhard; Markotić, Alemka; Kurolt, Ivan-Christian; Speck, Stephanie; Habuš, Josipa; Vucelja, Marko; Krajinović, Lidija Cvetko; Tadin, Ante; Margaletić, Josip; Essbauer, Sandra

    2014-07-01

    In Croatia, several rodent- and vector-borne agents are endemic and of medical importance. In this study, we investigated hantaviruses and, for the first time, tick-borne encephalitis virus (TBEV) and Rickettsia spp. in small wild rodents from two different sites (mountainous and lowland region) in Croatia. In total, 194 transudate and tissue samples from 170 rodents (A. flavicollis, n=115; A. agrarius, n=2; Myodes glareolus, n=53) were tested for antibodies by indirect immunofluorescence assays (IIFT) and for nucleic acids by conventional (hantaviruses) and real-time RT-/PCRs (TBEV and Rickettsia spp.). A total of 25.5% (24/94) of the rodents from the mountainous area revealed specific antibodies against hantaviruses. In all, 21.3% (20/94) of the samples from the mountainous area and 29.0% (9/31) from the lowland area yielded positive results for either Puumala virus (PUUV) or Dobrava-Belgrade virus (DOBV) using a conventional RT-PCR. All processed samples (n=194) were negative for TBEV by IIFT or real-time RT-PCR. Serological evidence of rickettsial infection was detected in 4.3% (4/94) rodents from the mountainous region. Another 3.2% (3/94) rodents were positive for Rickettsia spp. by real-time PCR. None of the rodents (n=76) from the lowland area were positive for Rickettsia spp. by real-time PCR. Dual infection of PUUV and Rickettsia spp. was found in one M. glareolus from the mountainous area by RT-PCR and real-time PCR, respectively. To our knowledge, this is the first detection of Rickettsia spp. in small rodents from Croatia. Phylogenetic analyses of S- and M-segment sequences obtained from the two study sites revealed well-supported subgroups in Croatian PUUV and DOBV. Although somewhat limited, our data showed occurrence and prevalence of PUUV, DOBV, and rickettsiae in Croatia. Further studies are warranted to confirm these data and to determine the Rickettsia species present in rodents in these areas.

  8. Rickettsia amblyommii infecting Amblyomma sculptum in endemic spotted fever area from southeastern Brazil.

    Science.gov (United States)

    Nunes, Emília de Carvalho; Vizzoni, Vinicius Figueiredo; Navarro, Daniel Leal; Iani, Felipe Campos de Melo; Durães, Liliane Silva; Daemon, Erik; Soares, Carlos Augusto Gomes; Gazeta, Gilberto Salles

    2015-12-01

    The Rickettsia bacteria include the aetiological agents for the human spotted fever (SF) disease. In the present study, a SF group Rickettsia amblyommii related bacterium was detected in a field collected Amblyomma sculptum (Amblyomma cajennense species complex) tick from a Brazilian SF endemic site in southeastern Brazil, in the municipality of Juiz de Fora, state of Minas Gerais. Genetic analysis based on genes ompA,ompB and htrA showed that the detected strain, named R. amblyommii str. JF, is related to the species R. amblyommii.

  9. Rickettsia amblyommii infecting Amblyomma sculptum in endemic spotted fever area from southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Emília de Carvalho Nunes

    2015-12-01

    Full Text Available The Rickettsia bacteria include the aetiological agents for the human spotted fever (SF disease. In the present study, a SF groupRickettsia amblyommii related bacterium was detected in a field collected Amblyomma sculptum (Amblyomma cajennense species complex tick from a Brazilian SF endemic site in southeastern Brazil, in the municipality of Juiz de Fora, state of Minas Gerais. Genetic analysis based on genes ompA,ompB and htrA showed that the detected strain, named R. amblyommii str. JF, is related to the speciesR. amblyommii.

  10. Detection of Rickettsia felis in Wild Mammals from Three Municipalities in Yucatan, Mexico.

    Science.gov (United States)

    Panti-May, Jesús Alonso; Torres-Castro, Marco; Hernández-Betancourt, Silvia; Dzul-Rosado, Karla; Zavala-Castro, Jorge; López-Avila, Karina; Tello-Martín, Raúl

    2015-09-01

    The aim of this study was to provide information of the occurrence of Rickettsia felis in wild mammals from three municipalities in Yucatan, Mexico. The reactivity of rodent serum to Rickettsia antigens was detected in 80.9% (17 of 21) samples using immunofluorescence assay. Polymerase chain reaction identified rickettsial DNA in spleens of 43.5% (10 of 23) rodents and 57.1% (4 of 7) opossums. The identification of the rickettsial DNA was confirmed as R. felis by restriction fragment length polymorphism and DNA sequencing. This study comprises the first report of R. felis detection in wild mammals in Yucatan.

  11. Sister Carrie in China

    Institute of Scientific and Technical Information of China (English)

    殷希

    2015-01-01

    Sister Carrie has received many Chinese scholar's attention, and it has quantity relevance researches. Therefore, it is valuable to study why it is popular in China and it's education meaning for Chinese people. In addition, to analysis the domestic re-searches and find it's exist problems can help us make a new breakthrough from the study.

  12. Mapping of Monoclonal Antibody Binding Sites on CNBr Fragments of the S- Layer Protein Antigens of Rickettsia Typhi and Rickettsia Prowazekii

    Science.gov (United States)

    1992-01-01

    as the outermost component of several pathogenic gram-negative bacteria (Kay et al., their cell envelope (Palmer t at.. 1974: Ching et a.., 1984 Pei...antigen and expression of the protective crystalline surface layer from Rickettsia ricketsil: transcription and posttranslational protein antigen (SPAs...Publish- in procaryotes . J. Bacteriol. 170, 2891-2897. ing House of the Slovak Academy of Sciences, Bratislava. Streuli C. H. and Griffin B. E. (1987

  13. A novel spotted fever group Rickettsia infecting Amblyomma parvitarsum (Acari: Ixodidae) in highlands of Argentina and Chile.

    Science.gov (United States)

    Ogrzewalska, Maria; Nieri-Bastos, Fernanda A; Marcili, Arlei; Nava, Santiago; González-Acuña, Daniel; Muñoz-Leal, Sebastián; Ruiz-Arrondo, Ignacio; Venzal, José M; Mangold, Atilio; Labruna, Marcelo B

    2016-04-01

    The tick Amblyomma parvitarsum (Acari: Ixodidae) has established populations in Andean and Patagonic environments of South America. For the present study, adults of A. parvitarsum were collected in highland areas (elevation >3500 m) of Argentina and Chile during 2009-2013, and tested by PCR for rickettsial infection in the laboratory, and isolation of rickettsiae in Vero cell culture by the shell vial technique. Overall, 51 (62.2%) out of 82 A. parvitarsum adult ticks were infected by spotted fever group (SFG) rickettsiae, which generated DNA sequences 100% identical to each other, and when submitted to BLAST analysis, they were 99.3% identical to corresponding sequence of the ompA gene of Rickettsia sp. strain Atlantic rainforest. Rickettsiae were successfully isolated in Vero cell culture from two ticks, one from Argentina and one from Chile. DNA extracted from the third passage of the isolates of Argentina and Chile were processed by PCR, resulting in partial sequences for three rickettsial genes (gltA, ompB, ompA). These sequences were concatenated and aligned with rickettsial corresponding sequences available in GenBank. Phylogenetic analysis revealed that the A. pavitarsum rickettsial agent grouped under high bootstrap support in a clade composed by the SFG pathogens R. sibirica, R. africae, R. parkeri, Rickettsia sp. strain Atlantic rainforest, and two unnamed SFG agents of unknown pathogenicty, Rickettsia sp. strain NOD, and Rickettsia sp. strain ApPR. The pathogenic role of this A. parvitarsum rickettsia cannot be discarded, since several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections.

  14. Prevalence of Rickettsia and Bartonella species in Spanish cats and their fleas.

    Science.gov (United States)

    Gracia, María Jesús; Marcén, José Miguel; Pinal, Rocio; Calvete, Carlos; Rodes, Daniel

    2015-12-01

    The aim of this study was to determine the prevalence of Bartonella henselae, Rickettsia felis, and Rickettsia typhi in fleas and companion cats (serum and claws) and to assess their presence as a function of host, host habitat, and level of parasitism. Eighty-nine serum and claw samples and 90 flea pools were collected. Cat sera were assayed by IFA for Bartonella henselae and Rickettssia species IgG antibodies. Conventional PCRs were performed on DNA extracted from nails and fleas collected from cats. A large portion (55.8%) of the feline population sampled was exposed to at least one of the three tested vector-borne pathogens. Seroreactivity to B. henselae was found in 50% of the feline studied population, and to R. felis in 16.3%. R. typhi antibodies were not found in any cat. No Bartonella sp. DNA was amplified from the claws. Flea samples from 41 cats (46%) showed molecular evidence for at least one pathogen; our study demonstrated a prevalence rate of 43.3 % of Rickettsia sp and 4.4% of Bartonella sp. in the studied flea population. None of the risk factors studied (cat's features, host habitat, and level of parasitation) was associated with either the serology or the PCR results for Bartonella sp. and Rickettsia sp.. Flea-associated infectious agents are common in cats and fleas and support the recommendation that stringent flea control should be maintained on cats.

  15. A novel fluorescent in situ hybridization technique for detection of Rickettsia spp. in archival samples

    DEFF Research Database (Denmark)

    Svendsen, Claus Bo; Boye, Mette; Struve, Carsten

    2009-01-01

    A novel, sensitive and specific method for detecting Rickettsia spp. in archival samples is described. The method involves the use of fluorescently marked oligonucleotide probes for in situ hybridization. Specific hybridization of Ricekttsia was found without problems of cross-reactions with bact...

  16. Isolation and maintenance of Rickettsia raoultii in a Rhipicephalus sanguineus tick cell line.

    Science.gov (United States)

    Santibáñez, Sonia; Portillo, Aránzazu; Palomar, Ana M; Bell-Sakyi, Lesley; Romero, Lourdes; Oteo, José A

    2015-01-01

    Rickettsia raoultii, a member of the spotted fever group rickettsiae, has been implicated in cases of DEBONEL/TIBOLA/SENLAT, and has been detected in Dermacentor spp. and Rhipicephalus pumilio ticks by PCR. R. raoultii has been isolated in mammalian and tick cell lines. This study aimed to isolate R. raoultii from Spanish Dermacentor marginatus in tick cell lines. A single adult D. marginatus collected from vegetation in La Rioja (Northen Spain) in October 2012 was surface-sterilised, triturated and aliquots of the homogenate were inoculated into a panel of tick cell lines derived from embryonic Rhipicephalus sanguineus, Rhipicephalus evertsi and Ixodes ricinus. Cultures were maintained at 28 °C with weekly medium changes and checked by Gimenez stain for Rickettsia-like intracellular organisms. After 50 days of incubation, intracellular Rickettsia-like organisms were observed in the R. sanguineus cell line RML-RSE using Gimenez stain. PCR assays and sequencing of fragments of 16S RNA, ompB and ompA genes in DNA extracted from the culture suspension showed 100% identity with R. raoultii. Growth of intracellular microorganisms was not observed in preparations of the other tick cell lines. In conclusion, the tick cell line RML-RSE is a useful system for the isolation and maintenance of R. raoultii.

  17. Novel Candidatus rickettsia species detected in nostril tick from human, Gabon, 2014.

    Science.gov (United States)

    Lopez-Velez, Rogelio; Palomar, Ana M; Oteo, José A; Norman, Francesca F; Pérez-Molina, José A; Portillo, Aránzazu

    2015-02-01

    We report the identification of a nymphal nostril tick (Amblyomma sp.) from a national park visitor in Gabon and subsequent molecular detection and characterization of tickborne bacteria. Our findings provide evidence of a potentially new Rickettsia sp. circulating in Africa and indicate that tick bites may pose a risk to persons visiting parks in the region.

  18. Rickettsia infection in five areas of the state of São Paulo, Brazil

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    Maurício C Horta

    2007-11-01

    Full Text Available This study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of São Paulo. Eight flea species (Adoratopsylla antiquorum antiquorum, Ctenocephalides felis felis, Polygenis atopus, Polygenis rimatus, Polygenis roberti roberti, Polygenis tripus, Rhopalopsyllus lugubris, and Rhopalopsyllus lutzi lutzi, and five tick species (Amblyomma aureolatum, Amblyomma cajennense, Amblyomma dubitatum, Ixodes loricatus, and Rhipicephalus sanguineus were collected from dogs, cats, and opossums. Rickettsia felis was the only rickettsia found infecting fleas, whereas Rickettsia bellii was the only agent infecting ticks, but no animal or human blood was shown to contain rickettsial DNA. Testing animal and human sera by indirect immunofluorescence assay against four rickettsia antigens (R. rickettsii, R. parkeri, R. felis, and R. bellii, some opossum, dog, horse, and human sera reacted to R. rickettsii with titers at least four-fold higher than to the other three rickettsial antigens. These sera were considered to have a predominant antibody response to R. rickettsii. Using the same criteria, opossum, dog, and horse sera showed predominant antibody response to R. parkeri or a very closely related genotype. Our serological results suggest that both R. rickettsii and R. parkeri infected animals and/or humans in the studied areas.

  19. First report of Rickettsia raoultii in field collected Dermacentor reticulatus ticks from Austria.

    Science.gov (United States)

    Duscher, Georg G; Hodžić, Adnan; Weiler, Martin; Vaux, Alexander G C; Rudolf, Ivo; Sixl, Wolfdieter; Medlock, Jolyon M; Versteirt, Veerle; Hubálek, Zdenek

    2016-07-01

    In a set of pooled field collected Dermacentor reticulatus ticks, Rickettsia raoultii, the causative agent of Tick-borne lymphadenopathy/Dermacentor-borne necrosis erythema and lymphadenopathy, was found for the first time in Austria. The coordinates of the positive locations for tick and pathogen abundance are given and shown in a map.

  20. Seroepidemiological survey of Rickettsia spp. in dogs from the endemic area of Rickettsia parkeri rickettsiosis in Uruguay.

    Science.gov (United States)

    Lado, Paula; Costa, Francisco B; Verdes, José M; Labruna, Marcelo B; Venzal, José M

    2015-06-01

    Rickettsia parkeri rickettsiosis is a vector-borne zoonosis that occurs in some countries of the American continent. Following the first description and determination of the pathogenicity to humans in 2004 in USA, this bacterium has been reported in several South American countries. Human cases have been diagnosed in both Uruguay and Argentina in the past years. This study consisted in a serosurvey of 1000 domestic dogs living in the endemic area of rickettsiosis in Uruguay, where Amblyomma triste is the tick vector. Sera were analyzed by Indirect Immunofluorescence Assay (IFA), against antigens of three different rickettsial species: R. rhipicephali, R. felis and R. parkeri. It was determined that 20.3% of the dogs had antibodies that reacted to at least one of the three species tested, taking as cut off ≥64 titers. Furthermore, 140 of the seropositive dogs (14%) had a titer at least 4 times higher to R. parkeri than those of any of the other species, thus, it was considered that the immune response was stimulated by that species in particular. This is the first serological survey in primary hosts for adults of A. triste in Uruguay, and therefore the first prevalence values are reported. Adult A. triste ticks collected from the environment as well as from dogs were analyzed by PCR in order to confirm the current circulation of the agent in the area. In this matter, two out of 28 ticks from dogs, and 3 out of 53 ticks from the environment were positive, and the corresponding sequence analysis revealed 100% similarity with R. parkeri strain maculatum.

  1. "Rickettsia amblyommii" and R. montanensis infection in dogs following natural exposure to ticks.

    Science.gov (United States)

    Barrett, Anne; Little, Susan E; Shaw, Edward

    2014-01-01

    To determine the risk of canine infection with spotted fever group (SFG) Rickettsia spp. following natural tick exposure, 10 dogs determined to be free of evidence of exposure to or infection with tick-borne disease agents were exposed to ticks via weekly walks in a wooded area in north-central Oklahoma. After each walk, dogs were examined and the number and species of ticks present were recorded. The dogs were then returned to outdoor kennels to allow the infestations and subsequent transmission of any pathogens to proceed. Serum samples and whole blood were collected from each dog twice weekly for 121 days and evaluated via indirect fluorescence antibody (IFA) for antibodies reactive to Rickettsia rickettsii, R. montanensis, and "R. amblyommii," and by PCR for evidence of Rickettsia spp. Dogs became infested with a total of 57-108 ticks over the entire 8-week infestation period (weekly average tick infestation=12.0±4.1). The great majority of the ticks present were Amblyomma americanum (90.5%), with a small number of Dermacentor variabilis and A. maculatum also identified. All (10/10) dogs seroconverted to R. rickettsii, R. montanensis, and "R. amblyommii," with mean maximum inverse titers of 1176, 1448, and 6654, respectively, for all dogs in the study. Maximum inverse titers to "R. amblyommii" ranged from 4096 to 16,384 and were higher in 9/10 dogs than maximum inverse titers to R. rickettsii or R. montanensis. Sequence-confirmed SFG Rickettsia spp. (R. montanensis and "R. amblyommii") were occasionally, but not consistently, identified from whole blood by PCR. Taken together, our data suggest that, in areas where A. americanum is common, antibodies reactive to R. rickettsii in dogs may be due instead to infection with "R. amblyommii" or other, closely related SFG Rickettsia spp.

  2. Molecular evidence for novel tick-associated spotted fever group rickettsiae from Thailand.

    Science.gov (United States)

    Hirunkanokpun, Supanee; Kittayapong, Pattamaporn; Cornet, Jean-Paul; Gonzalez, Jean-Paul

    2003-03-01

    Ticks are of considerable medical and veterinary importance because they directly harm the host through their feeding action and indirectly through vectoring many bacterial pathogens. Despite many ticks being known from Thailand, very little is known about the bacteria they may harbor. We report here the results of a survey of tick-associated bacteria in Thailand. A total of 334 individuals representing 14 species of ticks in five genera were collected from 10 locations in Thailand and were examined for the human pathogens, Borrelia, Francisella, Rickettsia, and the common arthropod endosymbionts, Wolbachia, by polymerase chain reaction (PCR) assay using specific primers. Rickettsial DNA was detected in 30% (9/30) of Amblyomma testudinarium (Koch, 1844) collected from Khao Yai National Park, Nakhon Nayok Province and 16.84% (16/95) of Hemaphysalis ornithophila (Hoogstraal and Kohls, 1959) collected from Khao Yai National Park, Nakhon Nayok Province and Khao Ang Rue Nai Wildlife Sanctuary, Chachoengsao Province. Rickettsial DNA was not detected in any of the other tick species and no DNA of Borrelia, Francisella, or Wolbachia was detected in any of 14 tick species. Phylogenetic relationships among the rickettsiae detected in this study and those of other rickettsiae were inferred from comparison of sequences of the 17-kDa antigen gene, the citrate synthase gene (gltA), and the 190-kDa outer membrane protein gene (ompA). Results indicated that the three Thai rickettsiae detected in this study represent new rickettsial genotypes and form a separate cluster among the spotted fever group rickettsiae.

  3. Bacteria of the genus Rickettsia in ticks (Acari: Ixodidae) collected from birds in Costa Rica.

    Science.gov (United States)

    Ogrzewalska, Maria; Literák, Ivan; Capek, Miroslav; Sychra, Oldřich; Calderón, Víctor Álvarez; Rodríguez, Bernardo Calvo; Prudencio, Carlos; Martins, Thiago F; Labruna, Marcelo B

    2015-06-01

    The aim of this study was to document the presence of Rickettsia spp. in ticks parasitizing wild birds in Costa Rica. Birds were trapped at seven locations in Costa Rica during 2004, 2009, and 2010; then visually examined for the presence of ticks. Ticks were identified, and part of them was tested individually for the presence of Rickettsia spp. by polymerase chain reaction (PCR) using primers targeting fragments of the rickettsial genes gltA and ompA. PCR products were DNA-sequenced and analyzed in BLAST to determine similarities with previously reported rickettsial agents. A total of 1878 birds were examined, from which 163 birds (9%) were infested with 388 ticks of the genera Amblyomma and Ixodes. The following Amblyomma (in decreasing order of abundance) were found in immature stages (larvae and nymphs): Amblyomma longirostre, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma sabanerae, Amblyomma varium, Amblyomma maculatum, and Amblyomma ovale. Ixodes ticks were represented by Ixodes minor and two unclassified species, designated here as Ixodes sp. genotype I, and Ixodes sp. genotype II. Twelve of 24 tested A. longirostre ticks were found to be infected with 'Candidatus Rickettsia amblyommii', and 2 of 4 A. sabanerae were found to be infected with Rickettsia bellii. Eight of 10 larval Ixodes minor were infected with an endosymbiont (a novel Rickettsia sp. agent) genetically related to the Ixodes scapularis endosymbiont. No rickettsial DNA was found in A. calcaratum, A. coelebs, A. maculatum, A. ovale, A. varium, Ixodes sp. I, and Ixodes sp. II. We report the occurrence of I. minor in Costa Rica for the first time and a number of new bird host-tick associations. Moreover, 'Candidatus R. amblyommii' and R. bellii were found in A. longirostre and A. sabanerae, respectively, in Costa Rica for the first time.

  4. Pesquisa de Rickettsia spp em carrapatos Amblyomma cajennense e Amblyomma dubitatum no Estado de São Paulo Survey of Rickettsia spp in the ticks Amblyomma cajennense and Amblyomma dubitatum in the State of São Paulo

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    Richard Campos Pacheco

    2009-06-01

    Full Text Available Foi pesquisada a presença de riquétsias em 3.545 carrapatos Amblyomma cajennense e 2.666 Amblyomma dubitatum. Através do teste de hemolinfa, reação em cadeia pela polimerase e isolamento de rickettsia em cultivo celular, todos os Amblyomma cajennense foram negativos, sendo que 634 (23,8% Amblyomma dubitatum mostraram-se infectados com Rickettsia bellii.The presence of rickettsial infection was surveyed in 3,545 Amblyomma cajennense ticks and 2,666 Amblyomma dubitatum ticks. Using the hemolymph test, polymerase chain reaction and isolation of Rickettsia in cell cultures, all of the Amblyomma cajennense were negative, whereas 634 (23.8% of the Amblyomma dubitatum ticks were shown to be infected with Rickettsia bellii.

  5. Clinical and laboratorial evidence of Rickettsia felis infections in Latin America Evidência clínica e laboratorial de infecções por Rickettsia felis na América Latina

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    Márcio Antônio Moreira Galvão

    2004-06-01

    Full Text Available After the discovery and initial characterization of Rickettsia felis in 1992 by Azad and cols, and the subsequent first description of a human case of infection in 1994, there have been two communications of human rickettsiosis cases caused by Rickettsia felis in Latin America. The first one was published in 2000 by Zavala-Velazquez and cols in Mexico. In 2001 Raoult and cols described the occurrence of two human cases of Rickettsia felis rickettsiosis in Brazil. In the present discussion these two articles were compared and after the description of the principal signs and symptoms, it was concluded that more studies are needed with descriptions of a greater number of patients to establish the true frequency of the clinical signs and symptoms present in Rickettsia felis rickettsiosis.Depois da descoberta e caracterização inicial da Rickettsia felis em 1992 por Azad e cols, e à descrição subseqüente do primeiro caso de infecção humana em 1994, houveram duas comunicações de rickettsioses causadas por Rickettsia felis na América Latina. A primeira foi feita por Zavala-Velazquez e cols em 2000 no México. Em 2001, Raoult e cols descreveram a ocorrência de dois casos humanos de rickettsiose por Rickettsia felis no Brasil. Na presente discussão, esses dois artigos foram comparados, e depois da descrição dos principais sinais e sintomas, conclui-se que outros estudos são necessários, com a participação de um maior número de pacientes, para se estabelecer a verdadeira freqüência dos sinais clínicos e sintomas presentes nas rickettsioses por Rickettsia felis.

  6. Spotted fever group Rickettsia in Amblyomma dubitatum tick from the urban area of Campo Grande, Mato Grosso do Sul, Brazil.

    Science.gov (United States)

    Matias, Jaqueline; Garcia, Marcos Valério; Cunha, Rodrigo Casquero; Aguirre, André de Abreu Rangel; Barros, Jacqueline Cavalvante; Csordas, Bárbara Guimarães; Andreotti, Renato

    2015-03-01

    Rickettsia infection of each tick was evaluated by the hemolymph test and polymerase chain reaction (PCR) targeting gltA and ompA genes. All hemolymph tests were negative and PCR of one A. dubitatum detected both Rickettsia genes. Sequence of ompA exhibited a 99% identity with Rickettsia parkeri and R. africae and a 98% identity with R. sibirica. Rickettsia of the spotted fever group in A. dubitatum is described for the first time in an urban area within the municipality of Campo Grande in the state of Mato Grosso do Sul (MS), Brazil. This finding reinforces the importance of more detailed studies to determine the role of A. dubitatum in the transmission of spotted fever agents.

  7. Detection, Isolation and Characterization of an Agent from Febrile Patients in Malaysia Serologically Reactive with Rickettsia sennetsu.

    Science.gov (United States)

    1983-12-01

    Rickettsia sennetsu and Ehrlichia canis Against Rickettsia #11908 Using the Indirect Fluorescent Antibody (IFA) test 13 CONCLUSIONS AND...to Ehrlichia canis of a protein fraction isolated from the R. sennetsu agent. -3- FOREWORD Citations of commercial organizations and trade names in...and Ehrlichia canis with Human Sera from Southeast Asia. Country Number Number Percentage Group of Origin of Cases of Positive Positive 1 Malaysia 200

  8. New Spotted Fever Group Rickettsia in a Rhipicephalus turanicus Tick Removed from a Child in Eastern Sicily, Italy

    OpenAIRE

    Eremeeva, Marina E; Stromdahl, Ellen Y.

    2011-01-01

    A new genotype of spotted fever group Rickettsia (SFGR) was identified in Rhipicephalus turanicus from eastern Sicily. On the basis of current molecular criteria, the genetic characteristics obtained from multiple locus sequence typing satisfy the requirements for Candidatus status of this SFGR. Further detection and identification of this SFGR during entomological and clinical surveys will be required to establish the prevalence of this Rickettsia and its potential pathogenicity for humans.

  9. The first report of Rickettsia spp. in Amblyomma nodosum in the State of Mato Grosso do Sul, Brazil.

    Science.gov (United States)

    Almeida, Robson F C; Garcia, Marcos V; Cunha, Rodrigo C; Matias, Jaqueline; Labruna, Marcelo B; Andreotti, Renato

    2013-02-01

    Ticks are vectors of various pathogens, including Rickettsia spp., which are responsible for causing an emerging disease of global significance. In the present study, an epidemiological survey was performed to identify Rickettsia spp. of the spotted fever group (SFG) in ticks and wild hosts in a native forest adjacent to livestock farming activity. The ticks and blood were evaluated by a hemolymph test and by PCR using the primers CS78 and CS323, which target a partial sequence of the enzyme citrate synthase (gltA) gene. Positive samples by PCR were further tested with the primers Rr190.70p and Rr190.602n, which target a 532-bp fragment of the rickettsial 190-kDa outer membrane protein gene (ompA). In addition, an indirect immunofluorescence assay (IFA) was performed to detect antibodies against Rickettsia spp. in horses that inhabited the same area. From the 43 animals that were captured, 192 ticks were collected; the ticks belonged to the species Amblyomma cajennense, A. ovale, and A. nodosum. All blood samples and hemolymph tests were negative. Four samples of A. nodosum that were collected from Tamandua tetradactyla were positive for Rickettsia spp. by PCR, and 8 samples of horse serum displayed titers greater than or equal to 1:64 by IFA. The phylogenetic analysis based on the DNA sequence of the ompACG gene demonstrated that Rickettsia spp. CG (the canadensis group) segregate in the same cluster as Rickettsia parkeri strain COOPERI, with a bootstrap value of 78%. These results indicate that Rickettsia spp. CG circulate among the tick population in the study area, which has a constant presence of livestock and humans. This may be the same species of Rickettsia that was recorded in A. nodosum throughout the Atlantic forest.

  10. "Christian carrying goomies".

    Science.gov (United States)

    1994-01-01

    Dr. Passingan Usurup tells critics of his pragmatic approach on condom promotion that he is a Christian carrying condoms for Christ. He is head of the University of Papua New Guinea Medical Center and is credited with developing an AIDS/HIV policy for the Papua New Guinea Defence Force. The condoms were named Goomy and promoted at launching in 1992 in a blue packet under the slogan "The bond that guards." Goomy was chosen as the name because it is pidgin for rubber, chewing gum, and anything associated with rubber. Blue packets were chosen over the calls of most soldiers for a camouflage design because of its universal appeal as the color of the sea and sky and because it was the preference of women in the airlines. Once firmly ensconced in his role at the University, Usurup plans to develop a policy for students and staff and help to conduct AIDS prevention and education activities on campus. He will encourage students to test for HIV rather than highlighting the gloom and doom of infection and disease.

  11. Silencing urease: a key evolutionary step that facilitated the adaptation of Yersinia pestis to the flea-borne transmission route.

    Science.gov (United States)

    Chouikha, Iman; Hinnebusch, B Joseph

    2014-12-30

    The arthropod-borne transmission route of Yersinia pestis, the bacterial agent of plague, is a recent evolutionary adaptation. Yersinia pseudotuberculosis, the closely related food-and water-borne enteric species from which Y. pestis diverged less than 6,400 y ago, exhibits significant oral toxicity to the flea vectors of plague, whereas Y. pestis does not. In this study, we identify the Yersinia urease enzyme as the responsible oral toxin. All Y. pestis strains, including those phylogenetically closest to the Y. pseudotuberculosis progenitor, contain a mutated ureD allele that eliminated urease activity. Restoration of a functional ureD was sufficient to make Y. pestis orally toxic to fleas. Conversely, deletion of the urease operon in Y. pseudotuberculosis rendered it nontoxic. Enzymatic activity was required for toxicity. Because urease-related mortality eliminates 30-40% of infective flea vectors, ureD mutation early in the evolution of Y. pestis was likely subject to strong positive selection because it significantly increased transmission potential.

  12. Sympatric occurrence of Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis concinna ticks and Rickettsia and Babesia species in Slovakia.

    Science.gov (United States)

    Svehlová, Andrea; Berthová, Lenka; Sallay, Balázs; Boldiš, Vojtech; Sparagano, Olivier A E; Spitalská, Eva

    2014-09-01

    Vojka nad Dunajom in the south-west of the Slovak Republic is a locality with sympatric occurrence of 3 species of ticks. This study investigated the spatial distribution of Dermacentor reticulatus, Ixodes ricinus, and Haemaphysalis concinna ticks in this area and determined the prevalence of Babesia and Rickettsia species in questing adults of these tick species considered as potential risk for humans and animals. Ticks were collected by blanket dragging over the vegetation from September 2011 to October 2012. All ticks were subjected to DNA extraction and individually assayed with PCR-based methods targeting the gltA, sca4, 23S rRNA genes of Rickettsia spp. and the 18S rRNA gene of Babesia spp. D. reticulatus was the dominant species occurring in this area (67.7%, n=600), followed by I. ricinus (31.8%, n=282) and H. concinna (0.5%, n=4) ticks. Rickettsial infection was determined in 10.8% (n=65) and 11.7% (n=33) of D. reticulatus and I. ricinus ticks, respectively. Babesia spp. infection was confirmed in 1.8% (n=11) of D. reticulatus and 0.4% (n=1) of I. ricinus ticks. DNA of 6 different pathogenic tick-borne species, Rickettsia helvetica, Rickettsia monacensis, Rickettsia slovaca, Rickettsia raoultii, Babesia canis, and Babesia venatorum were identified in this locality with sympatric occurrence of I. ricinus, D. reticulatus, and H. concinna ticks.

  13. Ticks on passerines from the Archipelago of the Azores as hosts of borreliae and rickettsiae.

    Science.gov (United States)

    Literak, Ivan; Norte, Ana Claudia; Núncio, Maria Sofia; de Carvalho, Isabel Lopes; Ogrzewalska, Maria; Nováková, Markéta; Martins, Thiago F; Sychra, Oldrich; Resendes, Roberto; Rodrígues, Pedro

    2015-07-01

    We examined the presence of borreliae and rickettsiae bacteria in ticks from wild passerine birds on three islands of the Archipelago of the Azores, the westernmost region of Palearctic. A total of 266 birds belonging to eight species from seven families were examined on São Miguel, Santa Maria and Graciosa islands in 2013. Ticks collected from these birds consisted of 55 Ixodes frontalis (22 larvae, 32 nymphs, 1 adult female) and 16 Haemaphysalis punctata nymphs. Turdus merula and Erithacus rubecula were the birds most infested with both tick species. Three T. merula in Santa Maria were infested with 4 I. frontalis infected with Borrelia turdi. No rickettsiae were found in the ticks. We report for the first time the presence of I. frontalis and B. turdi on the Azores islands and we showed that the spatial distribution reaches further west than previously thought.

  14. Tests on ticks from wild birds collected in the eastern United States for rickettsiae and viruses

    Science.gov (United States)

    Clifford, C.M.; Sonenshine, D.E.; Atwood, E.L.; Robbins, C.S.; Hughes, L.E.

    1969-01-01

    Results of tests for rickettsiae and viruses on 4,266 ticks taken from more than 10,000 birds, comprising 150 species, in the eastern United States indicated the presence of two agents: Rickettsia rickettsii and an agent of the typhus group. Infection with R. rickettsii was indicated in 24 pools of Haemaphysalis leporispalustris, five pools of Ixodes dentatus, one pool of Ixodes brunneus, and two pools that contained both I. dentatus and H. leporispalustris. The pools positive for R. rickettsii were from a variety of locations in the eastern U. S. The typhus-group agent was demonstrated only once, in a single pool of H. leporispalustris taken at Kent Point, Maryland. A strain of R. rickettsii was isolated from a pool of 21 larval H. leporispalustris collected at Ocean City, Maryland. This agent possessed several characteristics of other strains of low virulence isolated previously in this region by various authors.

  15. Defending the fort: a role for defensin-2 in limiting Rickettsia montanensis infection of Dermacentor variabilis.

    Science.gov (United States)

    Pelc, R S; McClure, J C; Sears, K T; Chung, A; Rahman, M S; Ceraul, S M

    2014-08-01

    The importance of tick defensins is evidenced by their expression in a wide variety of tick tissues and prevalence across many tick genera. To date, the functional and biological significance of defensin-2 as a rickettsiastatic or rickettsiacidal antimicrobial peptide has not been addressed. In a previous study, defensin-2 transcription was shown to increase in Dermacentor variabilis ticks challenged with Rickettsia montanensis. In the present study, the hypothesis that defensin-2 is functional as a rickettsiastatic and/or rickettsiacidal antimicrobial peptide is tested. We show that defensin-2 plays a role in reducing burden after acquisition of Rickettsia montanensis through capillary feeding. Moreover, defensin-2 is shown to associate with R. montanensis in vitro and in vivo, causing cytoplasmic leakiness.

  16. Discovery of Rickettsia species in Dermacentor niveus Neumann ticks by investigating the diversity of bacterial communities.

    Science.gov (United States)

    Zhuang, Lu; Wang, Cheng-Yan; Tong, Yi-Gang; Tang, Fang; Yang, Hong; Liu, Wei; Cao, Wu-Chun

    2014-09-01

    Ticks (Dermacentor niveus Neumann) were collected from Tacheng, Xinjiang Uygur Autonomous Region, and their bacterial diversity was investigated using the 16S RNA gene library method from one pooled sample. A total of 452 clones was successfully sequenced and assigned to 4 phyla. The dominant phylum was the Proteobacteria, accounting for 62.8% of all the clones of the 16S rRNA gene at the confidence level 80%. The other sequences were assigned to the phyla Bacteroidetes, Firmicutes, Actinobacteria and accounted for 13.5%, 12.4%, and 11.3%, respectively. These results provide an insight into the bacterial diversity associated with D. niveus ticks in the natural environment of Tacheng. They indicate the occurrence of Rickettsia raoultii and Rickettsia slovaca in D. niveus ticks in this area, and as a consequence, cases of TIBOLA/DEBONEL may occur (tick-borne lymphadenopathy/Dermacentor-borne necrosis erythema and lymphadenopathy).

  17. First molecular detection of Rickettsia parkeri in Amblyomma tigrinum and Amblyomma dubitatum ticks from Uruguay.

    Science.gov (United States)

    Lado, Paula; Castro, Oscar; Labruna, Marcelo B; Venzal, José M

    2014-10-01

    Rickettsia parkei is the etiological agent of spotted fever in Uruguay, where is transmitted to humans by the tick Amblyomma triste. In the present study, ticks were collected from capybaras (Hydrochoerus hydrochaeris) and domestic dogs during 2011-2012 in different parts of Uruguay. Three out of 11 (27.3%) Amblyomma dubitatum ticks collected from capybaras, and 4 out of 6 (66.7%) Amblyomma tigrinum ticks collected from dogs were shown by molecular analyses to be infected by Rickettsia parkeri strain Maculatum 20. Until the present work, A. triste was the only tick species that was found infected by R. parkeri in Uruguay. This is the first report of R. parkeri infecting these two tick species in Uruguay, expanding the current distribution of this rickettsial pathogen in the country.

  18. Molecular Detection of Rickettsia africae in Amblyomma variegatum Collected from Sudan.

    Science.gov (United States)

    Nakao, Ryo; Qiu, Yongjin; Salim, Bashir; Hassan, Shawgi Mohamed; Sugimoto, Chihiro

    2015-05-01

    Despite the increasing awareness of the importance of emerging vector-borne diseases, human tick-borne diseases, particularly rickettsial infections, are overlooked, especially in the countries such as Sudan with limited resources to perform molecular-based surveys. This study aimed at detection and genetic characterization of Rickettsia spp. in ticks collected from Sudan. The samples were first screened for the presence of rickettsial agents by gltA real-time PCR and subsequently characterized by gltA and ompA PCR and size-based multispacer typing. The results demonstrated the wide distribution of Rickettsia africae and/or closely related species across Sudan. The results of this report highlight the need for careful consideration of rickettsial infections in patients with nonmalarial febrile illness in this country. Nationwide surveillance on ticks associated with human rickettsial infections in Sudan is warranted.

  19. Molecular survey of Rickettsia, Ehrlichia, and Anaplasma infection of domestic cats in Japan.

    Science.gov (United States)

    Sasaki, Hiromi; Ichikawa, Yasuaki; Sakata, Yoshimi; Endo, Yasuyuki; Nishigaki, Kazuo; Matsumoto, Kotaro; Inokuma, Hisashi

    2012-12-01

    The prevalence of Rickettsia, Ehrlichia, and Anaplasma in 1764 DNA samples extracted from feline peripheral blood from all 47 prefectures in Japan was evaluated by screening real-time PCR, genus-specific PCR, and DNA nucleotide sequencing. The survey revealed that all cats were negative for Rickettsia infection. Two cats were positive for Ehrlichia or Anaplasma based on the screening PCR assay. Nucleotide sequence analysis of the partial 16S rRNA including the divergent region near the 3'-end revealed that the 2 positives were most similar to Anaplasma bovis with percent identities of 99.8% and 99.2%. This was the first detection of A. bovis DNA fragments in cats. Although these 2 cats showed stomatitis, both were also infected with feline immunodeficiency virus. The relationship between A. bovis carriage and clinical disease is not yet understood.

  20. A prospective study evaluating the presence of Rickettsia in Danish patients with sarcoidosis

    DEFF Research Database (Denmark)

    Svendsen, Claus Bo; Milman, Nils; Nielsen, Henrik Winther;

    2009-01-01

    prospectively enrolled in the study. The diagnosis was confirmed by biopsy in 18 and by clinical characteristics in 8 patients; 11 patients with different non-sarcoid lung diseases were recruited as controls. We obtained information regarding tick exposure and sarcoid disease manifestations by a structured....... There was no difference in the reported frequency of tick bite between patients and controls. In conclusion, we found no evidence of Rickettsia being involved in the pathogenesis of sarcoidosis in Denmark....

  1. Transposon insertion reveals pRM, a plasmid of Rickettsia monacensis.

    Science.gov (United States)

    Baldridge, Gerald D; Burkhardt, Nicole Y; Felsheim, Roderick F; Kurtti, Timothy J; Munderloh, Ulrike G

    2007-08-01

    Until the recent discovery of pRF in Rickettsia felis, the obligate intracellular bacteria of the genus Rickettsia (Rickettsiales: Rickettsiaceae) were thought not to possess plasmids. We describe pRM, a plasmid from Rickettsia monacensis, which was detected by pulsed-field gel electrophoresis and Southern blot analyses of DNA from two independent R. monacensis populations transformed by transposon-mediated insertion of coupled green fluorescent protein and chloramphenicol acetyltransferase marker genes into pRM. Two-dimensional electrophoresis showed that pRM was present in rickettsial cells as circular and linear isomers. The 23,486-nucleotide (31.8% G/C) pRM plasmid was cloned from the transformant populations by chloramphenicol marker rescue of restriction enzyme-digested transformant DNA fragments and PCR using primers derived from sequences of overlapping restriction fragments. The plasmid was sequenced. Based on BLAST searches of the GenBank database, pRM contained 23 predicted genes or pseudogenes and was remarkably similar to the larger pRF plasmid. Two of the 23 genes were unique to pRM and pRF among sequenced rickettsial genomes, and 4 of the genes shared by pRM and pRF were otherwise found only on chromosomes of R. felis or the ancestral group rickettsiae R. bellii and R. canadensis. We obtained pulsed-field gel electrophoresis and Southern blot evidence for a plasmid in R. amblyommii isolate WB-8-2 that contained genes conserved between pRM and pRF. The pRM plasmid may provide a basis for the development of a rickettsial transformation vector.

  2. Epitope mapping of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi.

    OpenAIRE

    Lachumanan, R; Devi, S; Cheong, Y M; Rodda, S J; Pang, T.

    1993-01-01

    Binding studies of 160 overlapping, synthetic octapeptides from the hydrophilic regions of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi with sera from patients with scrub typhus revealed 15 immunodominant peptides which are recognized by all the sera tested. Further analysis of the specificity of peptide binding with five of these peptides indicated that the peptides showed significantly stronger binding to scrub typhus patients' sera than they did to sera from patients ...

  3. Seasonal analysis of Rickettsia species in ticks in an agricultural site of Slovakia.

    Science.gov (United States)

    Špitalská, Eva; Stanko, Michal; Mošanský, Ladislav; Kraljik, Jasna; Miklisová, Dana; Mahríková, Lenka; Bona, Martin; Kazimírová, Mária

    2016-03-01

    Many rickettsiae of the spotted fever group are emerging pathogens causing serious diseases associated with vertebrate hosts. Ixodidae ticks are known as their vectors. Investigation of the relative abundance of questing Ixodes ricinus and their infection with Rickettsia spp. in an agricultural site comprising a game reserve in Slovakia was the aim of this study. In total, 2198 I. ricinus (492 larvae, 1503 nymphs and 203 adults) were collected by flagging the vegetation along 100 m(2) transects in Rozhanovce (eastern Slovakia): 334, 595 and 1269 in 2011, 2012 and 2013, respectively. Considering questing nymphs and adults, the highest relative density of 81 individuals/100 m(2) was observed in May 2013, the lowest of 0.3 individuals/100 m(2) in March 2012. A total of 1056 ticks (853 nymphs, 100 females and 103 males; 2011: n = 329, 2012: n = 509 and 2013: n = 218) were individually screened by PCR-based methods for the presence of Rickettsia spp. The overall prevalences were 7.3% for nymphs, 15% for females, 7.8% for males; 7.0% in 2011, 8.4% in 2012, and 8.7% in 2013. The maximum prevalences were observed in July in nymphs and in May in adults. Sequencing showed infection with R. helvetica in 73 ticks (72.6% nymphs, 16.4% females, 11% males) and with R. monacensis in 11 ticks (8 nymphs, 3 females). The results showed the circulation of pathogenic Rickettsia species in the agricultural site and a potential risk for humans to encounter infected ticks.

  4. Amblyomma imitator: a novel vector for Rickettsia rickettsii in Mexico and South Texas

    OpenAIRE

    Oliveira, Karla Andrade de

    2010-01-01

    Rickettsioses, diseases of worldwide importance, are caused by small, gramnegative, obligately intracellular bacteria that are transmitted to humans via ticks, fleas, mites or lice. The genus Rickettsia has been classically divided into two groups, the typhus group (TG) and the spotted fever group (SFG). In the United States and Mexico, transmission of Rocky Mountain spotted fever (RMSF) has been attributed to ticks of the genera Dermacentor (D. variabilis and D. andersoni), Rhipicephalus (R...

  5. Bacterial diversity in Amblyomma americanum (Acari: Ixodidae) with a focus on members of the genus Rickettsia.

    Science.gov (United States)

    Heise, Stephanie R; Elshahed, M S; Little, S E

    2010-03-01

    The lone star tick, Amblyomma americanum (Acari: Ixodidae), is commonly reported from people and animals throughout the eastern U.S. and is associated with transmission of a number of emerging diseases. To better define the microbial communities within lone star ticks, 16S rRNA gene based analysis using bacteria-wide primers, followed by sequencing of individual clones (n = 449) was used to identify the most common bacterial operational taxonomic units (OTUs) present within colony-reared and wild A. americanum. The colony-reared ticks contained primarily sequence affiliated with members of the genus Coxiella (89%; 81/91), common endosymbionts of ticks, and Brevibacterium (11%; 10/91). Similarly, analysis of clones from unfed wild lone star ticks revealed that 96.7% (89/92) of all the OTUs identified were affiliated with Coxiella-like endosymbionts, as compared with only 5.1-11.7% (5/98-9/77) of those identified from wild lone star ticks after feeding. In contrast, the proportion of OTUs identified as Rickettsia sp. in wild-caught ticks increased from 2.2% (2/92) before feeding to as high as 46.8% (36/77) after feeding, and all Rickettsia spp. sequences recovered were most similar to those described from the spotted fever group Rickettsia, specifically R. amblyommii and R. massiliae. Additional characterization of the Rickettsiales tick community by polymerase chain reaction, cloning, and sequencing of 17 kDa and gltA genes confirmed these initial findings and suggested that novel Rickettsia spp. are likely present in these ticks. These data provide insight into the overall, as well as the rickettsial community of wild lone star ticks and may ultimately aid in identification of novel pathogens transmitted by A. americanum.

  6. Detection of Leishmania infantum, Babesia canis, and rickettsiae in ticks removed from dogs living in Italy.

    Science.gov (United States)

    Trotta, Michele; Nicetto, Martina; Fogliazza, Alessandro; Montarsi, Fabrizio; Caldin, Marco; Furlanello, Tommaso; Solano-Gallego, Laia

    2012-12-01

    The aims of this study were to determine natural infections by Anaplasma phagocytophilum/Anaplasma platys, Bartonella henselae, Ehrlichia canis, Leishmania infantum, Rickettsia spp., Babesia spp., and Hepatozoon spp. by molecular methods in ticks (n=91) removed from dogs with clinical signs and laboratory abnormalities compatible with tick-borne diseases (n=22) living in Italy and to assess the distribution and species of ticks encountered. Ticks from dogs living in southern Italy were all identified as Rhipicephalus sanguineus (n=25), ticks from central Italy included Rh. sanguineus (n=8) and Ixodes ricinus (n=9), ticks from northern Italy included Rh. sanguineus (n=45), Dermacentor marginatus (n=3), and one I. ricinus. Leishmania infantum, Rickettsia spp., and Babesia canis were the only pathogens detected in 7 (8%), 4 (4%), and 2 (2%) out of 91 ticks, respectively. L. infantum was detected in I. ricinus from central Italy and in Rh. sanguineus from northern and central Italy. Rickettsia conorii and Ri. massiliae were detected in Rh. sanguineus ticks from central and southern Italy (Sicily), respectively. Bab. canis was detected in D. marginatus ticks from northern Italy.

  7. Arsenophonus nasoniae and Rickettsiae Infection of Ixodes ricinus Due to Parasitic Wasp Ixodiphagus hookeri.

    Directory of Open Access Journals (Sweden)

    Monika Bohacsova

    Full Text Available Arsenophonus nasoniae, a male-killing endosymbiont of chalcid wasps, was recently detected in several hard tick species. Following the hypothesis that its presence in ticks may not be linked to the direct occurrence of bacteria in tick's organs, we identified A. nasoniae in wasps emerging from parasitised nymphs. We confirmed that 28.1% of Ixodiphagus hookeri wasps parasitizing Ixodes ricinus ticks were infected by A. nasoniae. Moreover, in examined I. ricinus nymphs, A. nasoniae was detected only in those, which were parasitized by the wasp. However, in part of the adult wasps as well as in some ticks that contained wasp's DNA, we did not confirm A. nasoniae. We also found, that in spite of reported male-killing, some newly emerged adult wasp males were also infected by A. nasoniae. Additionally, we amplified the DNA of Rickettsia helvetica and Rickettsia monacensis (known to be Ixodes ricinus-associated bacteria in adult parasitoid wasps. This may be related either with the digested bacterial DNA in wasp body lumen or with a role of wasps in circulation of rickettsiae among tick vectors.

  8. Disrupting protein expression with Peptide Nucleic Acids reduces infection by obligate intracellular Rickettsia.

    Directory of Open Access Journals (Sweden)

    Rebecca S Pelc

    Full Text Available Peptide Nucleic Acids (PNAs are single-stranded synthetic nucleic acids with a pseudopeptide backbone in lieu of the phosphodiester linked sugar and phosphate found in traditional oligos. PNA designed complementary to the bacterial Shine-Dalgarno or start codon regions of mRNA disrupts translation resulting in the transient reduction in protein expression. This study examines the use of PNA technology to interrupt protein expression in obligate intracellular Rickettsia sp. Their historically intractable genetic system limits characterization of protein function. We designed PNA targeting mRNA for rOmpB from Rickettsia typhi and rickA from Rickettsia montanensis, ubiquitous factors important for infection. Using an in vitro translation system and competitive binding assays, we determined that our PNAs bind target regions. Electroporation of R. typhi and R. montanensis with PNA specific to rOmpB and rickA, respectively, reduced the bacteria's ability to infect host cells. These studies open the possibility of using PNA to suppress protein synthesis in obligate intracellular bacteria.

  9. Disrupting protein expression with Peptide Nucleic Acids reduces infection by obligate intracellular Rickettsia.

    Science.gov (United States)

    Pelc, Rebecca S; McClure, Jennifer C; Kaur, Simran J; Sears, Khandra T; Rahman, M Sayeedur; Ceraul, Shane M

    2015-01-01

    Peptide Nucleic Acids (PNAs) are single-stranded synthetic nucleic acids with a pseudopeptide backbone in lieu of the phosphodiester linked sugar and phosphate found in traditional oligos. PNA designed complementary to the bacterial Shine-Dalgarno or start codon regions of mRNA disrupts translation resulting in the transient reduction in protein expression. This study examines the use of PNA technology to interrupt protein expression in obligate intracellular Rickettsia sp. Their historically intractable genetic system limits characterization of protein function. We designed PNA targeting mRNA for rOmpB from Rickettsia typhi and rickA from Rickettsia montanensis, ubiquitous factors important for infection. Using an in vitro translation system and competitive binding assays, we determined that our PNAs bind target regions. Electroporation of R. typhi and R. montanensis with PNA specific to rOmpB and rickA, respectively, reduced the bacteria's ability to infect host cells. These studies open the possibility of using PNA to suppress protein synthesis in obligate intracellular bacteria.

  10. Isolation of Rickettsia massiliae from Rhipicephalus sanguineus Ticks, Buenos Aires (Argentina).

    Science.gov (United States)

    Cicuttin, G L; De Salvo, M N; La Rosa, I; Dohmen, F E Gury

    2015-12-01

    Rickettsia massiliae , a member of the spotted fever group of Rickettsia, was first isolated from a Rhipicephalus turanicus tick in France. In the New World, it has been detected in Rhipicephalus sanguineus ticks from different geographical locations in Argentina and the United States, but it has only been isolated in Arizona. The aim of this study was the isolation and genetic characterization of R. massiliae from R. sanguineus ticks collected from dogs in Buenos Aires city, Argentina. In total, 49 R. sanguineus ticks were collected from 10 dogs and grouped into 10 pools of 4-5 specimens. With a PCR assay, which detects a fragment of the Rickettsia genus-specific 23S-5S intergenic space, 1 pool of 5 ticks was found positive. Generated sequences exhibited 100% identity with R. massiliae . A new isolate, named CABA, was obtained from this pool by inoculating it into monolayers of Vero cells. Genotypic characteristics were determined, and results showed that fragments of the 23S-5S intergenic space, ompA, ompB, gltA, htrA, and sca1 genes had great similarity with R. massiliae strain Bar29 (Spain). Although few human cases have been confirmed for this pathogen, its circulation in urban areas is of great importance to public health. This isolation improves knowledge of the circulating pathogen and could improve future diagnostic processes as it allows the production of more specific antigens for serological testing.

  11. ISOLATION OF Rickettsia bellii FROM Amblyomma ovale AND Amblyomma incisum TICKS FROM SOUTHERN BRAZIL

    Directory of Open Access Journals (Sweden)

    Richard Pacheco

    2008-08-01

    Full Text Available Objective. To isolate and characterize rickettsiae from the ticks Amblyomma ovale and Amblyomma incisum collected in the state of São Paulo. Materials and methods. Adult, free-living A. ovale and A. incisum were collected in an Atlantic rainforest area in the state of São Paulo, Brazil. Each tick was tested using the hemolymph assay; samples from positive ticks were placed in shell vials in order to isolate rickettsiae and subsequently grown in Vero cells. Amplification of three rickettsial genes (gltA, htrA and ompA was attempted using polymerase chain reaction (PCR for each isolate obtained. Amplicons were subsequently sequenced. Results. A total of 388 A. incisum and 50 A. ovale were collected. Only one A. incisum and one A. ovale were hemolymph-test positive. Rickettsiae were successfully isolated from these ticks; however establishment in Vero cell culture was successful only for the isolate from A. ovale. Bacterial contamination in the first cell passage of the A. incisum isolate precluded successful isolation of the organism. PCR products were obtained with the gltA and htrA primers for the two isolates, but no product was obtained with the ompA primers. By BLAST analysis, partial gltA and htrA sequences of isolates from A. ovale and A. incisum were similar to the corresponding sequences of R. bellii. Conclusions. This is the first report of R. bellii infecting A. incisum and the first successful isolation from A. ovale.

  12. Rickettsia africae in Amblyomma variegatum and domestic ruminants on eight Caribbean islands.

    Science.gov (United States)

    Kelly, Patrick; Lucas, Helene; Beati, Lorenza; Yowell, Charles; Mahan, Suman; Dame, John

    2010-12-01

    We used PCRs with omp A primers to determine if spotted fever group rickettsiae occurred in Amblyomma variegatum from 6 Caribbean islands. Positive amplicons were obtained from ticks from the U.S. Virgin Islands (9/18; 50%), Dominica (39/171; 30%), Montserrat (2/5; 40%), Nevis (17/34; 50%), St. Kitts (46/227; 20%), and St. Lucia (1/14; 7%). Sequences for a convenience sample of reaction products obtained from A. variegatum on St. Kitts (7), American Virgin Islands (4), Montserrat (2), and St. Lucia (1) were 100% homologous with that of Rickettsia africae , the agent of African tick-bite fever. To determine if transmission of R. africae occurred, we used Rickettsia rickettsii antigen in IFA tests and found positive titers (≥ 1/80) with sera from cattle, goats, and sheep from Dominica (24/95 [25%], 2/136 [2%], 0/58 [0%]), Nevis (12/45 [27%], 5/157 [3%], 0/90 [0%]), St. Kitts (2/43 [5%], 1/25 [4%), 1/35 [3%]), and St. Lucia (6/184 [3%] cattle), respectively. No seropositive animals were found in Grenada (0/4, 0/98/, 0/86), Montserrat (0/12, 0/26, 0/52), or Puerto Rico (0/80 cattle). Our study indicates that R. africae and African tick-bite fever are widespread in the Caribbean.

  13. Anaplasma phagocytophilum and Rickettsia spp. infections in hard ticks (Ixodes ricinus) in the city of Hanover (Germany): revisited.

    Science.gov (United States)

    Tappe, Julia; Strube, Christina

    2013-09-01

    The present study aimed to determine the prevalence of Rickettsiales (A. phagocytophilum and Rickettsia spp.) in 2100 I. ricinus ticks collected at 10 different sampling sites every month during the tick season 2010 in the city of Hanover, northern Germany. At the same time, the results served as a fifth-year-follow-up study to monitor whether changes or stagnation of tick infection rates - possibly due to climate change--were obvious or not. To detect infections with A. phagocytophilum and/or Rickettsia spp., tick samples were analysed by quantitative real-time PCR. Differentiation of Rickettsia species was accomplished using real-time pyrosequencing technology. Overall, 4.5% (94/2100) of the collected ticks were tested positive for A. phagocytophilum and 26.2% (551/2100) were positive for Rickettsia spp. infections. Species differentiation of Rickettsia-positive ticks via real-time pyrosequencing was possible in 48.6% (268/551) of samples, which were all identified as R. helvetica. Coinfections with both pathogens were found in 1.0% (20/2100) of ticks. Statistically significant seasonal fluctuations between sampling months as well as local differences between sampling sites were detected for Rickettsia spp. infection rates. For A. phagocytophilum infections, only significant seasonal variations were found. When comparing infection rates of Hanoverian ticks in 2010 to those in 2005, infection rates of A. phagocytophilum-infected nymphs increased statistically significant (P=0.008, power: 0.762) from 2.3% in 2005 (Schicht et al., 2011) to 4.5% in 2010. Rickettsia spp. infections in female ticks decreased significantly (P=0.049, power: 0.491) from 41.8% in 2005 (Schicht et al., 2012) to 32.4% in 2010. Comparison of the remaining tick stages showed no statistically significant differences.

  14. Survey of ticks collected in Mississippi for Rickettsia, Ehrlichia, and Borrelia species.

    Science.gov (United States)

    Goddard, Jerome; Sumner, John W; Nicholson, William L; Paddock, Christopher D; Shen, John; Piesman, Joseph

    2003-12-01

    From November 1999 through October 2000, we tested ticks collected from vegetation as well as from deer, dogs, and humans for spotted fever group (SFG) rickettsiae, Ehrlichia chaffeensis, and Borrelia spp. spirochetes. A total of 149 adult ticks representing four species was collected from 11 collection sites from southwestern to northern Mississippi. Amblyomma americanum was most commonly collected (n=68), followed by Ixodes scapularis (n=53). The bird tick, Ixodes brunneus (usually rare), was the third most commonly collected tick (n=17). Eleven Dermacentor variabilis were also collected. Ticks were cut longitudinally to make smears on three microscope slides. The remaining body parts were frozen at -65 degrees C for additional testing. Tick smears were stained by direct immunofluorescence assays (DFA) for Rickettsia spp. and Borrelia spp., while indirect immunofluorescence assays (IFA) were used for Ehrlichia spp. The corresponding tick for each positive smear was evaluated using PCR analysis. None of the 149 ticks tested was DFA positive for Borrelia spp. However, smears of 30 (20%) and 32 (22%) ticks reacted with anti-E. chaffeensis sera and anti-R. rickettsii conjugate (known to react with several members of the spotted fever group), respectively. None of the ticks staining with the IFA for Ehrlichia was positive for E. chaffeensis using PCR. However, 23 (72%) of 32 FA-positive ticks for SFG rickettsiae yielded amplicons of the appropriate size when tested using a PCR assay for SFG rickettsiae, corresponding to an overall infection rate with SFG rickettsiae among the collected ticks of 15%. Smears of 12 (71%) of 17 I. brunneus revealed abundant bacilliform bacteria. PCR amplification of DNA from a single I. brunneus containing these bacteria was performed using universal primers for the 16S rRNA gene as well as Borrelia-specific primers. The predominant sequence obtained using the universal primers did not match any sequence in GenBank, but it showed 91

  15. Prevalence of Rickettsiales (Anaplasma phagocytophilum and Rickettsia spp.) in hard ticks (Ixodes ricinus) in the city of Hamburg, Germany.

    Science.gov (United States)

    May, Kathrin; Strube, Christina

    2014-06-01

    To narrow the gap of missing knowledge on Rickettsia spp. and Anaplasma phagocytophilum infections in ticks in northwestern Germany and, at the same time, to provide first prevalence data on these pathogens in the city of Hamburg, a total of 1,400 questing Ixodes ricinus ticks were collected at ten different public green areas from April until October 2011. Ticks were examined using probe-based quantitative real-time PCR. A percentage of 3.6% (51/1,400) ticks were tested positive for A. phagocytophilum infections divided into 2.1% (3/141) adults [1.7% (1/60) females and 2.5% (2/81) males] and 3.8% (48/1,259) nymphs. The percentage of infected ticks per sampling site varied statistically significantly from 0.7% (1/140) to 12.1% (17/140), whereas between sampling months, no statistically significant differences were observed (2.0-6.5%, 4-13/140). The overall Rickettsia spp. infection rate was 52.5% (735/1,400). In adult ticks, Rickettsia spp. infection rate was 56% (79/141) divided into 61.7% (37/60) infected females and 51.9% (42/81) infected males. Nymphs showed an infection rate of 52.1% (656/1,259). In contrast to A. phagocytophilum infections, no statistically significant differences in Rickettsia spp. infection rates among sampling sites (44.3-63.6%, 62-89/140) were observed, whereas seasonal variations were obvious: the percentage of Rickettsia-positive ticks was significantly lower in April (36.5%, 73/200) and May (29.5%, 59/200) compared to the summer and fall months (55.0-64.5%, 110-129/200). Rickettsia species differentiation via real-time pyrosequencing revealed Rickettsia helvetica as the only occurring species. Co-infections with both Rickettsia spp. and A. phagocytophilum were detected in 2.0% (28/1,400) of the ticks. The present study revealed that in the city of Hamburg, the tick infection rate with A. phagocytophilum is comparable with other German data, whereas the Rickettsia spp. infection rate of 52.5% is by far the highest prevalence detected in

  16. Spotted fever group rickettsiae detected in immature stages of ticks parasitizing on Iberian endemic lizard Lacerta schreiberi Bedriaga, 1878.

    Science.gov (United States)

    Kubelová, Michaela; Papoušek, Ivo; Bělohlávek, Tomáš; de Bellocq, Joëlle Goüy; Baird, Stuart J E; Široký, Pavel

    2015-09-01

    Spotted fever rickettsioses are tick-borne diseases of growing public health concern. The prevalence of rickettsia-infected ticks and their ability to parasitize humans significantly influence the risk of human infection. Altogether 466 Ixodes ricinus ticks (428 nymphs and 38 larvae) collected from 73 Lacerta schreiberi lizards were examined by PCR targeting the citrate synthetase gene gltA for the presence of Rickettsia spp. Rickettsial DNA was detected in 47% of nymphs and 31.6% of larvae. They were subsequently subjected to a second PCR reaction using primers derived from the outer membrane protein rOmpA encoding gene (ompA) to detect spotted fever group rickettsiae (SFG). This analysis shows that 41.4% of nymphs and 7.9% of larvae collected from the lizards contain DNA of SFG rickettsiae. Sequencing of 43 randomly selected samples revealed two different haplotypes, both closely related to R. monacensis (39 and 4 samples, respectively). The remaining ompA negative Rickettsia spp. samples were determined to be R. helvetica based on sequencing of ompB and gltA fragments. Our results indicate that the role of Iberian endemic lizard L. schreiberi and its ectoparasites in the ecology and epidemiology of zoonotic SFG rickettsioses may be appreciable.

  17. The detection of spotted fever group Rickettsia DNA from fever patients in Dali, Yunnan%云南省大理州发热患者血液中检测斑点热群立克次体

    Institute of Scientific and Technical Information of China (English)

    亚红祥; 王静林

    2012-01-01

    目的 调查云南省大理州不明原因发热患者是否存在斑点热.方法 用巢式-聚合酶链反应法扩增患者血液中的立克次体属groEL基因,并进行核酸序列鉴定和分析.结果 20例患者血液中检出1例立克次体核酸阳性(检出率5%),其序列分析与GenBank中Rickcttsia rickcttsii Iowa、Rickcttsia peacockii Rustic、Rickcttsia sibirica等斑点热群立克次体株的同源性最高(为99%).结论 首次证实云南大理地区存在斑点热患者,医疗部门应加强对斑点热的诊断与鉴别.%Objective To identify the pathogen of patients with fever with unknown origin and determine whether they were infected with spotted fever group Rickettsia. Methods Nested polymerase chain reaction (nPCR) was conducted to amplify groEL gene of rickettsia from the blood samples of the patients, the nucleotide sequencing and identification were carried out. Results Rickettsial DNA was detected in 1 of the 20 patients (5% ). The groEL gene of the strain shared high homology (99%) with Rickcttsia rickcttsii Iowa, Rickcttsia peacockii Rustic and Rickettsia sibirica. Conclusion It was the first time to diagnose the patient with spotted fever in Dali, Yunnan province. It is necessary to enhance the differential diagnosis of spotted fever in local medical institutions.

  18. On fast carry select adders

    Science.gov (United States)

    Shamanna, M.; Whitaker, S.

    1992-01-01

    This paper presents an architecture for a high-speed carry select adder with very long bit lengths utilizing a conflict-free bypass scheme. The proposed scheme has almost half the number of transistors and is faster than a conventional carry select adder. A comparative study is also made between the proposed adder and a Manchester carry chain adder which shows that the proposed scheme has the same transistor count, without suffering any performance degradation, compared to the Manchester carry chain adder.

  19. On fast carry select adders

    Science.gov (United States)

    Shamanna, M.; Whitaker, S.

    This paper presents an architecture for a high-speed carry select adder with very long bit lengths utilizing a conflict-free bypass scheme. The proposed scheme has almost half the number of transistors and is faster than a conventional carry select adder. A comparative study is also made between the proposed adder and a Manchester carry chain adder which shows that the proposed scheme has the same transistor count, without suffering any performance degradation, compared to the Manchester carry chain adder.

  20. High prevalence of Rickettsia typhi and Bartonella species in rats and fleas, Kisangani, Democratic Republic of the Congo.

    Science.gov (United States)

    Laudisoit, Anne; Falay, Dadi; Amundala, Nicaise; Akaibe, Dudu; de Bellocq, Joëlle Goüy; Van Houtte, Natalie; Breno, Matteo; Verheyen, Erik; Wilschut, Liesbeth; Parola, Philippe; Raoult, Didier; Socolovschi, Cristina

    2014-03-01

    The prevalence and identity of Rickettsia and Bartonella in urban rat and flea populations were evaluated in Kisangani, Democratic Republic of the Congo (DRC) by molecular tools. An overall prevalence of 17% Bartonella species and 13% Rickettsia typhi, the agent of murine typhus, was found in the cosmopolitan rat species, Rattus rattus and Rattus norvegicus that were infested by a majority of Xenopsylla cheopis fleas. Bartonella queenslandensis, Bartonella elizabethae, and three Bartonella genotypes were identified by sequencing in rat specimens, mostly in R. rattus. Rickettsia typhi was detected in 72% of X. cheopis pools, the main vector and reservoir of this zoonotic pathogen. Co-infections were observed in rodents, suggesting a common mammalian host shared by R. typhi and Bartonella spp. Thus, both infections are endemic in DRC and the medical staffs need to be aware knowing the high prevalence of impoverished populations or immunocompromised inhabitants in this area.

  1. The potential role of migratory birds in transmission cycles of Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp.

    Science.gov (United States)

    Hildebrandt, Anke; Franke, Jan; Meier, Frank; Sachse, Svea; Dorn, Wolfram; Straube, Eberhard

    2010-06-01

    Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp. are potentially emerging tick-borne pathogens, whereas many issues about their ecology, e.g. reservoir host specificity, are still unclear. In spring 2007, we collected 191 feeding Ixodes ricinus ticks from 99 birds of 11 different species on a German bird conservation island in the Baltic Sea. Babesia spp. were detected in 4.7% (9/191), A. phagocytophilum was present in 2.6% (5/191), and Rickettsia spp. were identified in 7.3% (14/191) of the investigated ticks. Further characterization of Babesia spp. infections resulted in B. divergens and B. microti. Among the Rickettsia spp. infections, we identified at least 2 different species: R. monacensis and R. helvetica. Furthermore, 2 ticks harboured mixed infections. Our study provides first interesting insights into the role of migratory birds in the distribution of several emerging tick-borne pathogens.

  2. Aislamiento de Rickettsia bellii a partir de garrapatas Amblyomma ovale y Amblyomma incisum procedentes del sur de Brasil

    OpenAIRE

    PACHECO, Richard; ROSA, Simone; Richtzenhain,Leonardo José; Szabó,Matias Pablo Juan; LABRUNA, Marcelo Bahia

    2008-01-01

    Objective. To isolate and characterize rickettsiae from the ticks Amblyomma ovale and Amblyomma incisum collected in the state of São Paulo. Materials and methods. Adult, free-living A. ovale and A. incisum were collected in an Atlantic rainforest area in the state of São Paulo, Brazil. Each tick was tested using the hemolymph assay; samples from positive ticks were placed in shell vials in order to isolate rickettsiae and subsequently grown in Vero cells. Amplification of three rickettsial g...

  3. Rickettsiosis cutáneo ganglionar por Rickettsia conorii en el Uruguay Cutaneous-ganglionar rickettsiosis by Rickettsia conorii in Uruguay

    Directory of Open Access Journals (Sweden)

    Ismael A. Conti-Diaz

    1990-10-01

    Full Text Available Se refieren 3 casos autóctonos de rickettsiosis cutáneo ganglionar trasmitidos por garrapatas de perros (Amblyomma maculatum, en uno de ellos en el Uruguay. Dos de los 3 casos fueron seguramente provocados por Rickettsia conorii de acuerdo a los resultados de la reacción específica de inmunofluorescencia indirecta - IgM, anti R. conorii. Se incluye un tercer paciente no estudiado con tal técnica, por la similitud clínico-epidemiológica, la reactividad del suero frente al Proteus OX 19 y la rápida respuesta a la tetraciclina. La no descripción previa de la rickettsiosis por R. conorii en forma autóctona en el área de las Américas confiere especial interés a la comunicación, recomendándose la búsqueda de la afección en otros países de la región.Three autochthonous cases of cutaneous-ganglionar rickettsiosis transmitted by dogs ticks (Amblyomma maculatum in one of them are reported. Two of the three cases were undoubtely produced by Rickettsia conorii according to the results of the specific indirect immunofluorescence technique IEF-IgM anti R. conorii. A third case is included due to the clinical epidemiological similarity, the positive serum reactivity with Proteus O x 19 and the rapid response to tetracycline. Autochthonous rickettsiosis by R. conorii has not been previously registered in the American area what confers special interest to this communication. The search of the disease in the other countries of the region is suggested.

  4. Differences in intracellular fate of two spotted fever group Rickettsia in macrophage-like cells

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    Pedro Curto

    2016-07-01

    Full Text Available Spotted fever group (SFG rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (R. conorii and Rocky Mountain spotted fever (R. rickettsii. Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickettsial diseases. These studies raise the hypothesis that the role of macrophages in rickettsial pathogenesis may have been underappreciated. Herein, we evaluated the ability of two SFG rickettsial species, R. conorii (a recognized human pathogen and R. montanensis (a non-virulent member of SFG to proliferate in THP-1 macrophage-like cells, or within non-phagocytic cell lines. Our results demonstrate that R. conorii was able to survive and proliferate in both phagocytic and epithelial cells in vitro. In contrast, R. montanensis was able to grow in non-phagocytic cells, but was drastically compromised in the ability to proliferate within both undifferentiated and PMA-differentiated THP-1 cells. Interestingly, association assays revealed that R. montanensis was defective in binding to THP-1-derived macrophages; however, the invasion of the bacteria that are able to adhere did not appear to be affected. We have also demonstrated that R. montanensis which entered into THP-1-derived macrophages were rapidly destroyed and partially co-localized with LAMP-2 and cathepsin D, two markers of lysosomal compartments. In contrast, R. conorii was present as intact bacteria and free in the cytoplasm in both cell types. These findings suggest that a phenotypic difference between a non-pathogenic and a pathogenic SFG member lies in their respective ability to proliferate in macrophage-like cells, and may provide an explanation as to why certain SFG rickettsial species are not associated with

  5. Anti-Rickettsia spp. antibodies in free-ranging and captive capybaras from southern Brazil

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    Fernanda S. Fortes

    2011-11-01

    Full Text Available Capybaras (Hydrochaeris hydrochaeris are among the main hosts of Amblyomma spp. ticks, which is able to transmit Rickettsia species to human beings and animals. Since they are often infested with potential vector ticks, capybaras may be used as sentinels for rickettsiosis, such as the Brazilian Spotted Fever. The aim of the present study was to determine the prevalence of antibodies against Rickettsia spp. using the indirect immunofluorescence assay (IFA in 21 free-ranging and 10 captive animals from the Zoological Park of the 'Bela Vista Biological Sanctuary' (BVBS, Itaipu Binational, Foz do Iguaçu, Southern Brazil. Antigens of six rickettsial species already identified in Brazil (Rickettsia rickettsii, R. parkeri, R. bellii, R. rhipicephali, R. amblyommii and R. felis were used for IFA. Ticks from each capybara were collected for posterior taxonomic identification. A total of 19 (61.3% samples reacted to at least one of tested species. Seropositivity was found in 14 (45.2%, 12 (38.7%, 5 (16.1%, 4 (12.9%, 3 (9.7% and 3 (9.7% animals for R. rickettsii, R. bellii, R. parkeri, R. amblyommii, R. felis and R. rhipicephali, respectively. Two captive capybaras presented suggestive titers of R. rickettsii infection and one sample showed homologous reaction to R. parkeri. Only one free-ranging capybara presented evidence R. bellii infection. Ticks collected on capybaras were identified as Amblyomma dubitatum e Amblyomma sp. Results evidenced the rickettsial circulation in the area, suggesting a potential role of capybaras on bacterial life cycle.

  6. Genomic and comparative genomic analyses of Rickettsia heilongjiangensis provide insight into its evolution and pathogenesis.

    Science.gov (United States)

    Duan, Changsong; Xiong, Xiaolu; Qi, Yong; Gong, Wenping; Jiao, Jun; Wen, Bohai

    2014-08-01

    Rickettsia heilongjiangensis, the causative agent of far eastern spotted fever, is an obligate intracellular gram-negative bacterium that belongs to the spotted fever group rickettsiae. To understand the evolution and pathogenesis of R. heilongjiangensis, we analyzed its genome and compared it with other rickettsial genomes available in GenBank. The R. heilongjiangensis chromosome contains 1333 genes, including 1297 protein coding genes and 36 RNA coding genes. The genome also contains 121 pseudogenes, 54 insertion sequences, and 39 tandem repeats. Sixteen genes encoding the major components of the type IV secretion systems were identified in the R. heilongjiangensis genome. In total, 37 β-barrel outer membrane proteins were predicted in the genome, eight of which have been previously confirmed to be outer membrane proteins. In addition, 266 potential virulence factor genes, seven partially deleted antibiotic resistance genes, and a genomic island were identified in the genome. The codon usage in the genome is compatible with its low GC content, and the amino acid usage shows apparent bias. A comparative genomic analysis showed that R. heilongjiangensis and R. japonica share one unique fragment that may be a target sequence for a diagnostic assay. The orthologs of 37 genes of R. heilongjiangensis were found in pathogenic R. rickettsii str. Sheila Smith but not in non-pathogenic R. rickettsii str. Iowa, which may explain why R. heilongjiangensis is pathogenic. Pan-genome analysis showed that R. heilongjiangensis and 42 other rickettsiae strains share 693 core genes with a pan-genome size of 4837 genes. The pan-genome-based phylogeny showed that R. heilongjiangensis was closely related to R. japonica.

  7. Complementation of Rickettsia rickettsii RelA/SpoT restores a nonlytic plaque phenotype.

    Science.gov (United States)

    Clark, Tina R; Ellison, Damon W; Kleba, Betsy; Hackstadt, Ted

    2011-04-01

    Spotted fever group rickettsiae are known to produce distinct plaque phenotypes. Strains that cause lytic infections in cell culture form clear plaques, while nonlytic strains form opaque plaques in which the cells remain intact. Clear plaques have historically been associated with more-virulent species or strains of spotted fever group rickettsiae. We have selected spontaneous mutant pairs from two independent strains of Rickettsia rickettsii, the virulent R strain and the avirulent Iowa strain. A nonlytic variant of R. rickettsii R, which typically produces clear plaques, was isolated and stably maintained. A lytic variant of the Iowa strain, which characteristically produces opaque plaques, was also selected and maintained. Genomic resequencing of the variants identified only a single gene disrupted in each strain. In both cases, the mutation was in a gene annotated as relA/spoT-like. In the Iowa strain, a single mutation introduced a premature stop codon upstream from region encoding the predicted active site of RelA/SpoT and caused the transition to a lytic plaque phenotype. In R. rickettsii R, the nonlytic plaque phenotype resulted from a single-nucleotide substitution that shifted a tyrosine residue to histidine near the active site of the enzyme. The intact relA/spoT gene thus occurred in variants with the nonlytic plaque phenotype. Complementation of the truncated relA/spoT gene in the Iowa lytic plaque variant restored the nonlytic phenotype. The relA/spoT mutations did not affect the virulence of either strain in a Guinea pig model of infection; R strain lytic and nonlytic variants both induced fever equally, and the mutation in Iowa to a lytic phenotype did not cause them to become virulent.

  8. Characterization of Spotted Fever Group Rickettsiae in Flea and Tick Specimens From Northern Peru

    Science.gov (United States)

    2004-11-01

    this assay; but those of DNA from R. typhi Wilmington or Museibov strains, R. prowazekii, 11 species of SFG rickettsiae, Orientia, Ehrlichia , Bartonella...Ctenocephalides canis 6 (10.2) 0 Pulex irritan 11 (18.6) 0 Neotyphloceras crassispina 2 (3.4) 0 Xenopsylla cheopis 5 (8.5) 0 a The percentage based on the total...thase gene sequence: a new tool for phylogenetic analysis and identification of Ehrlichia . J. Clin. Microbiol. 39:3031–3039. 25. Jensenius, M., P. E

  9. Surface proteome analysis and characterization of surface cell antigen (Sca or autotransporter family of Rickettsia typhi.

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    Khandra T Sears

    Full Text Available Surface proteins of the obligate intracellular bacterium Rickettsia typhi, the agent of murine or endemic typhus fever, comprise an important interface for host-pathogen interactions including adherence, invasion and survival in the host cytoplasm. In this report, we present analyses of the surface exposed proteins of R. typhi based on a suite of predictive algorithms complemented by experimental surface-labeling with thiol-cleavable sulfo-NHS-SS-biotin and identification of labeled peptides by LC MS/MS. Further, we focus on proteins belonging to the surface cell antigen (Sca autotransporter (AT family which are known to be involved in rickettsial infection of mammalian cells. Each species of Rickettsia has a different complement of sca genes in various states; R. typhi, has genes sca1 thru sca5. In silico analyses indicate divergence of the Sca paralogs across the four Rickettsia groups and concur with previous evidence of positive selection. Transcripts for each sca were detected during infection of L929 cells and four of the five Sca proteins were detected in the surface proteome analysis. We observed that each R. typhi Sca protein is expressed during in vitro infections and selected Sca proteins were expressed during in vivo infections. Using biotin-affinity pull down assays, negative staining electron microscopy, and flow cytometry, we demonstrate that the Sca proteins in R. typhi are localized to the surface of the bacteria. All Scas were detected during infection of L929 cells by immunogold electron microscopy. Immunofluorescence assays demonstrate that Scas 1-3 and 5 are expressed in the spleens of infected Sprague-Dawley rats and Scas 3, 4 and 5 are expressed in cat fleas (Ctenocephalides felis. Sca proteins may be crucial in the recognition and invasion of different host cell types. In short, continuous expression of all Scas may ensure that rickettsiae are primed i to infect mammalian cells should the flea bite a host, ii to remain

  10. Solution structure of the cold-shock-like protein from Rickettsia rickettsii

    OpenAIRE

    Gerarden, Kyle P.; Fuchs, Andrew M.; Koch, Jonathan M.; Mueller, Melissa M.; Graupner, David R.; O’Rorke, Justin T.; Frost, Caleb D.; Heinen, Heather A.; Lackner, Emily R.; Schoeller, Scott J.; House, Paul G.; Peterson, Francis C.; Veldkamp, Christopher T.

    2012-01-01

    Rocky Mountain spotted fever is caused by Rickettsia rickettsii infection. R. rickettsii can be transmitted to mammals, including humans, through the bite of an infected hard-bodied tick of the family Ixodidae. Since the R. rickettsii genome contains only one cold-shock-like protein and given the essential nature of cold-shock proteins in other bacteria, the structure of the cold-shock-like protein from R. rickettsii was investigated. With the exception of a short α-helix found between β-stra...

  11. In vitro evaluation of josamycin, spiramycin, and erythromycin against Rickettsia rickettsii and R. conorii.

    OpenAIRE

    Raoult, D; Roussellier, P; Tamalet, J

    1988-01-01

    The antimicrobial activities of josamycin, erythromycin, and spiramycin against Rickettsia conorii and R. rickettsii were evaluated in two tests: a dye-uptake assay and a plaque assay. The MIC of josamycin was 1 microgram/ml for both species; the MICs of erythromycin and spiramycin were 4 to 8 and 16 to 32 micrograms/ml, respectively, for both species. Only josamycin may be of clinical use in treating spotted fever rickettsiosis. It may be useful in treating pregnant women and young children.

  12. In vitro evaluation of josamycin, spiramycin, and erythromycin against Rickettsia rickettsii and R. conorii.

    Science.gov (United States)

    Raoult, D; Roussellier, P; Tamalet, J

    1988-02-01

    The antimicrobial activities of josamycin, erythromycin, and spiramycin against Rickettsia conorii and R. rickettsii were evaluated in two tests: a dye-uptake assay and a plaque assay. The MIC of josamycin was 1 microgram/ml for both species; the MICs of erythromycin and spiramycin were 4 to 8 and 16 to 32 micrograms/ml, respectively, for both species. Only josamycin may be of clinical use in treating spotted fever rickettsiosis. It may be useful in treating pregnant women and young children.

  13. Rickettsiosis cutáneo ganglionar por Rickettsia conorii en el Uruguay

    OpenAIRE

    Ismael A. Conti-Diaz; Rubio, Ivonne; Raúl E. Somma Moreira; Pérez Bórmida,Graciela

    1990-01-01

    Se refieren 3 casos autóctonos de rickettsiosis cutáneo ganglionar trasmitidos por garrapatas de perros (Amblyomma maculatum, en uno de ellos) en el Uruguay. Dos de los 3 casos fueron seguramente provocados por Rickettsia conorii de acuerdo a los resultados de la reacción específica de inmunofluorescencia indirecta - IgM, anti R. conorii. Se incluye un tercer paciente no estudiado con tal técnica, por la similitud clínico-epidemiológica, la reactividad del suero frente al Proteus OX 19 y la r...

  14. Rickettsia typhi possesses phospholipase A2 enzymes that are involved in infection of host cells.

    Directory of Open Access Journals (Sweden)

    M Sayeedur Rahman

    Full Text Available The long-standing proposal that phospholipase A2 (PLA2 enzymes are involved in rickettsial infection of host cells has been given support by the recent characterization of a patatin phospholipase (Pat2 with PLA2 activity from the pathogens Rickettsia prowazekii and R. typhi. However, pat2 is not encoded in all Rickettsia genomes; yet another uncharacterized patatin (Pat1 is indeed ubiquitous. Here, evolutionary analysis of both patatins across 46 Rickettsia genomes revealed 1 pat1 and pat2 loci are syntenic across all genomes, 2 both Pat1 and Pat2 do not contain predicted Sec-dependent signal sequences, 3 pat2 has been pseudogenized multiple times in rickettsial evolution, and 4 ubiquitous pat1 forms two divergent groups (pat1A and pat1B with strong evidence for recombination between pat1B and plasmid-encoded homologs. In light of these findings, we extended the characterization of R. typhi Pat1 and Pat2 proteins and determined their role in the infection process. As previously demonstrated for Pat2, we determined that 1 Pat1 is expressed and secreted into the host cytoplasm during R. typhi infection, 2 expression of recombinant Pat1 is cytotoxic to yeast cells, 3 recombinant Pat1 possesses PLA2 activity that requires a host cofactor, and 4 both Pat1 cytotoxicity and PLA2 activity were reduced by PLA2 inhibitors and abolished by site-directed mutagenesis of catalytic Ser/Asp residues. To ascertain the role of Pat1 and Pat2 in R. typhi infection, antibodies to both proteins were used to pretreat rickettsiae. Subsequent invasion and plaque assays both indicated a significant decrease in R. typhi infection compared to that by pre-immune IgG. Furthermore, antibody-pretreatment of R. typhi blocked/delayed phagosomal escapes. Together, these data suggest both enzymes are involved early in the infection process. Collectively, our study suggests that R. typhi utilizes two evolutionary divergent patatin phospholipases to support its intracellular life

  15. Molecular detection of rickettsias DNA in ticks around northeast region of China%东北部分地区蜱携带几种病原立克次体的分子检测

    Institute of Scientific and Technical Information of China (English)

    吴琼; 冯立; 王洪军; 吴益民; 付学奇; 王卓; 张志强

    2012-01-01

    Objective To understand the prevalence of tick-borne rickettsias around northeast region of China. Methods Wild ticks were captured and polymerase chain reaction (PCR) was used to amplify the rickettsias DNA of spotted fever group, human granulocytic ehrlichia and Ehrlichia chaff eensis carried by ticks. Results Ehrlichia chaff eensis DNA was found in I. Persulcatus and D. silvarum with the positive rates of 3.29% and 1.88% respectively. Meanwhile, human granulocytic ehrlichia DNA was amplified from I. Persulcatus with the positive rate of 2. 95%. However spotted fever group Rickettsiae was mainly found in H. concinna, with as high as 6.67% ticks carrying this rickettsiae, higher than that in I. Persulcatus and D. silvarum which were only 1. 69% and 2. 36%. Conclusions 7. Persulcatus and D. silvarum are possibly the main hosts of human granulocytic ehrlichia and Ehrlichia chaff eensis , while H. concinna mainly carries spotted fever group Rickettsiae in northeast region of China, indicating that it might be the natural foci of spotted feve, human granulocytic anaplasma and Ehrlichiosis.%目的 为了解东北地区蜱中携带立克次体的情况.方法 应用人工小时布旗法采集东北部分地区不同生境的游离蜱,采用PCR作斑点热立克次体、查菲埃立克体、人粒细胞无形体DNA检测.结果 从东北地区全沟硬蜱和森林革蜱检出查菲埃立克体DNA,全沟硬蜱平均阳性率为3.29%,森林革蜱为1.88%;从全沟硬蜱检出人粒细胞无形体DNA,平均阳性率为2.98%;从嗜群血蜱检出斑点热立克次体DNA,其平均阳性率(6.67%)明显高于全沟硬蜱(1.69%)和森林革蜱(2.36%).结论 东北地区全沟硬蜱和森林革蜱可能是查菲埃立克体、人粒细胞无形体的主要携带媒介,嗜群血蜱主要携带斑点热立克次体,提示东北地区存在三种蜱媒立克次体病的自然疫源地.

  16. An Analysis of English Carrie

    Institute of Scientific and Technical Information of China (English)

    孙淑珍

    2004-01-01

    @@ Chapter Ⅰ Introduction Sitting in the rocking chair,Carrie dreams her future.This is the deep impression the novel"Sister Carrie"gives us,which is written by Theodore Dreiser(1871-1945),the great American realism writer.

  17. Shell-vial culture, coupled with real-time PCR, applied to Rickettsia conorii and Rickettsia massiliae-Bar29 detection, improving the diagnosis of the Mediterranean spotted fever.

    Science.gov (United States)

    Segura, Ferran; Pons, Immaculada; Sanfeliu, Isabel; Nogueras, María-Mercedes

    2016-04-01

    Rickettsia conorii and Rickettsia massiliae-Bar29 are related to Mediterranean spotted fever (MSF). They are intracellular microorganisms. The Shell-vial culture assay (SV) improved Rickettsia culture but it still has some limitations: blood usually contains low amount of microorganisms and the samples that contain the highest amount of them are non-sterile. The objectives of this study were to optimize SV culture conditions and monitoring methods and to establish antibiotic concentrations useful for non-sterile samples. 12 SVs were inoculated with each microorganism, incubated at different temperatures and monitored by classical methods and real-time PCR. R. conorii was detected by all methods at all temperatures since 7th day of incubation. R. massiliae-Bar29 was firstly observed at 28°C. Real-time PCR allowed to detected it 2-7 days earlier (depend on temperature) than classical methods. Antibiotics concentration needed for the isolation of these Rickettsia species from non-sterile samples was determined inoculating SV with R. conorii, R. massiliae-Bar29, biopsy or tick, incubating them with different dilutions of antibiotics and monitoring them weekly. To sum up, if a MSF diagnosis is suspected, SV should be incubated at both 28°C and 32°C for 1-3 weeks and monitored by a sensitive real-time PCR. If the sample is non-sterile the panel of antibiotics tested can be added.

  18. Antibodies against spotted fever group Rickettsia sp., in horses of the colombian Orinoquia

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    Diego A. Riveros-Pinilla

    2015-11-01

    Full Text Available Objective. It was determined the presence of antibodies against Rickettsia sp. of the spotted fever group, in horses of 8 municipalities of the Colombian Orinoquia. Matherials and methods. A cross-sectional study was conducted on 246 sera from apparently healthy horses and processed by the indirect immunofluorescence test (IFI. Results. General seropositivity was (2.85%; 7/246, while by municipalities the results were, Arauca (9.1%; 2/22, Saravena (5.6%; 1/18, San José del Guaviare (4.9%; 2/41, San Martín (3.8%; 1/26, Yopal (1.9%; 1/52. It was not identified the presence of antibodies in Puerto López (0/52, Puerto Gaitán (0/15 and Villavicencio (0/20. Four of the positive samples presented titles of 1:64, while the remaining 3 1:128. Conclusions. It shows the circulation of Rickettsia sp. of the Spotted Fever Group in horses in the region of the Colombian Orinoquia, suggesting the need for further studies to understand the ecoepidemiology of municipalities with presence of seropositive.

  19. Proteome analysis and serological characterization of surface-exposed proteins of Rickettsia heilongjiangensis.

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    Yong Qi

    Full Text Available BACKGROUND: Rickettsia heilongjiangensis, the agent of Far-Eastern spotted fever (FESF, is an obligate intracellular bacterium. The surface-exposed proteins (SEPs of rickettsiae are involved in rickettsial adherence to and invasion of host cells, intracellular bacterial growth, and/or interaction with immune cells. They are also potential molecular candidates for the development of diagnostic reagents and vaccines against rickettsiosis. METHODS: R. heilongjiangensis SEPs were identified by biotin-streptavidin affinity purification and 2D electrophoreses coupled with ESI-MS/MS. Recombinant SEPs were probed with various sera to analyze their serological characteristics using a protein microarray and an enzyme-linked immune sorbent assay (ELISA. RESULTS: Twenty-five SEPs were identified, most of which were predicted to reside on the surface of R. heilongjiangensis cells. Bioinformatics analysis suggests that these proteins could be involved in bacterial pathogenesis. Eleven of the 25 SEPs were recognized as major seroreactive antigens by sera from R. heilongjiangensis-infected mice and FESF patients. Among the major seroreactive SEPs, microarray assays and/or ELISAs revealed that GroEL, OmpA-2, OmpB-3, PrsA, RplY, RpsB, SurA and YbgF had modest sensitivity and specificity for recognizing R. heilongjiangensis infection and/or spotted fever. CONCLUSIONS: Many of the SEPs identified herein have potentially important roles in R. heilongjiangensis pathogenicity. Some of them have potential as serodiagnostic antigens or as subunit vaccine antigens against the disease.

  20. Serological evidence of Rickettsia and Coxiella burnetii in humans of Buenos Aires, Argentina.

    Science.gov (United States)

    Cicuttin, Gabriel Leonardo; Degiuseppe, Juan Ignacio; Mamianetti, Andrea; Corin, Marcela Viviana; Linares, María Cielo; De Salvo, María Nazarena; Dohmen, Federico Eugenio Gury

    2015-12-01

    In Buenos Aires city (Argentina), the circulation of these agents has been detected mainly in vectors and animals, few human cases having been described. The aim of our study was to determine the seroprevalence of Rickettsia (spotted fever--SFG--and typhus--TG--groups) and Coxiella burnetii (Q fever agent) in residents of Buenos Aires city. The study involved 99 participants. Rickettsia IgG antibodies against SFG and TG were detected by IFA in 28.3% and 16.2% of serum samples, respectively. SFG titers were mostly 1/64 (53.6%) with a maximum of 1/512 (3.5%) whereas TG titers ranged between 1/64 (62.5%) and 1/256 (6.3%). Only one sample showed a titer of 1/32 for C. burnetii (phases I and II). The circulation of these pathogens in urban areas such as the city of Buenos Aires should be considered by health services, especially at the primary care level.

  1. Molecular detection of Rickettsia bellii in Amblyomma rotundatum from imported red-footed tortoise (Chelonoides carbonaria).

    Science.gov (United States)

    Erster, Oran; Roth, Asael; Avni, Zvi; King, Rony; Shkap, Varda

    2015-06-01

    Introduction of exotic ticks and pathogens through international animal trade (farm animals and pets) is a serious threat to public health and local fauna. Rapid and correct identification of potential threats is an important step on the way to conduct an efficient control of imported pests. In this report we describe the molecular identification of the neotropic tick Amblyomma rotundatum intercepted from red-footed tortoise (Chelonoides carbonaria), imported to Israel from Florida, USA. Molecular analysis of the ticks conducted upon their identification, revealed that they were infected with Rickettsia bellii. Following their collection, the ticks were examined morphologically and five molecular markers were used to determine their taxonomic identity: cytochrome c oxidase subunit 1 (COX1), cytochrome b (CytB), 12S rRNA, 16S rRNA and internal transcribed sequence 2 (ITS-2). Molecular analysis indicated that all of the collected ticks were Amblyomma rotundatum. Using rickettsial gltA (citrate synthase) gene in real-time PCR analysis we found that approximately 25% of the intercepted ticks (8 of 33) were infected with Rickettsia bellii. It is concluded that accurate and timely identification of imported exotic ticks prevented their introduction to Israel, and that use of molecular tools may further improve the response to such potential threats.

  2. Detection of a novel Rickettsia sp. in soft ticks (Acari: Argasidae) in Algeria.

    Science.gov (United States)

    Lafri, Ismail; Leulmi, Hamza; Baziz-Neffah, Fadhila; Lalout, Reda; Mohamed, Chergui; Mohamed, Karakallah; Parola, Philippe; Bitam, Idir

    2015-01-01

    Argasid ticks are vectors of viral and bacterial agents that can infect humans and animals. In Africa, relapsing fever borreliae are neglected arthropod-borne pathogens that cause mild to deadly septicemia and miscarriage. It would be incredibly beneficial to be able to simultaneous detect and identify other pathogens transmitted by Argasid ticks. From 2012 to 2014, we conducted field surveys in 4 distinct areas of Algeria. We investigated the occurrence of soft ticks in rodent burrows and yellow-legged gull (Larus michahellis) nests in 10 study sites and collected 154 soft ticks. Molecular identification revealed the occurrence of two different soft tick genera and five species, including Carios capensis in yellow-legged gull nests and Ornithodoros occidentalis, Ornithodoros rupestris, Ornithodoros sonrai, Ornithodoros erraticus in rodent burrows. Rickettsial DNA was detected in 41/154, corresponding to a global detection rate of 26.6%. Sequences of the citrate synthase (gltA) gene suggest that this agent is a novel spotted fever group Rickettsia. For the first time in Algeria, we characterize a novel Rickettsia species by molecular means in soft ticks.

  3. Surveillance of Egyptian fleas for agents of public health significance: Anaplasma, Bartonella, Coxiella, Ehrlichia, Rickettsia, and Yersinia pestis.

    Science.gov (United States)

    Loftis, Amanda D; Reeves, Will K; Szumlas, Daniel E; Abbassy, Magda M; Helmy, Ibrahim M; Moriarity, John R; Dasch, Gregory A

    2006-07-01

    Serologic surveys in Egypt have documented human and animal exposure to vector-borne bacterial pathogens, but the presence and distribution of these agents in arthropods has not been determined. Between July 2002 and July 2003, fleas were collected from 221 mammals trapped in 17 cities throughout Egypt. A total of 987 fleas were collected, representing four species (Ctenocephalides felis, Echidnophaga gallinacea, Leptopsylla segnis, and Xenopsylla cheopis); 899 of these fleas were X. cheopis from rats (Rattus spp.). Fleas were tested for DNA from Anaplasma spp., Bartonella spp., Coxiella burnetii, Ehrlichia spp., Rickettsia spp., and Yersinia pestis. Rickettsia typhi, the agent of murine typhus, was detected in X. cheopis and L. segnis from rats from nine cities. A spotted-fever group Rickettsia sp. similar to "RF2125" was detected in E. gallinacea, and two unidentified spotted fever group Rickettsia were detected in two X. cheopis. Novel Bartonella genotypes were detected in X. cheopis and L. segnis from three cities. Coxiella burnetii was detected in two fleas. Anaplasma, Ehrlichia, and Y. pestis were not detected.

  4. Carrying Capacity:An Overview

    Institute of Scientific and Technical Information of China (English)

    Chen Shaofeng

    2004-01-01

    The concept of carrying capacity is derived from ecology, with widespread contentions of its theoretical connotations and applications in the international academic community, especially the impact of human activities on the environment.Disputes on carrying capacity have been occurring not only among biologists and ecologists, but also among mainstream economists. Based on their efforts,the author makes an attempt to describe its origin,connotations, problems, measurement, and at the same time note the latest international progress in this field.

  5. Molecular detection of Rickettsia aeschlimannii in Hyalomma spp. ticks from camels (Camelus dromedarius) in Nigeria, West Africa.

    Science.gov (United States)

    Kamani, J; Baneth, G; Apanaskevich, D A; Mumcuoglu, K Y; Harrus, S

    2015-06-01

    Several species of the spotted fever group rickettsiae have been identified as emerging pathogens throughout the world, including in Africa. In this study, 197 Hyalomma ticks (Ixodida: Ixodidae) collected from 51 camels (Camelus dromedarius) in Kano, northern Nigeria, were screened by amplification and sequencing of the citrate synthase (gltA), outer membrane protein A (ompA) and 17-kDa antigen gene fragments. Rickettsia sp. gltA fragments were detected in 43.3% (42/97) of the tick pools tested. Rickettsial ompA gene fragments (189 bp and 630 bp) were detected in 64.3% (n = 27) and 23.8% (n = 10) of the gltA-positive tick pools by real-time and conventional polymerase chain reaction (PCR), respectively. The amplicons were 99-100% identical to Rickettsia aeschlimannii TR/Orkun-H and R. aeschlimannii strain EgyRickHimp-El-Arish in GenBank. Furthermore, 17-kDa antigen gene fragments of 214 bp and 265 bp were detected in 59.5% (n = 25) and 38.1% (n = 16), respectively, of tick pools, and sequences were identical to one another and 99-100% identical to those of the R. aeschlimannii strain Ibadan A1 in GenBank. None of the Hyalomma impressum ticks collected were positive for Rickettsia sp. DNA. Rickettsia sp. gltA fragments (133 bp) were detected in 18.8% of camel blood samples, but all samples were negative for the other genes targeted. This is the first report to describe the molecular detection of R. aeschlimannii in Hyalomma spp. ticks from camels in Nigeria.

  6. RC1339/APRc from Rickettsia conorii is a novel aspartic protease with properties of retropepsin-like enzymes.

    Directory of Open Access Journals (Sweden)

    Rui Cruz

    2014-08-01

    Full Text Available Members of the species Rickettsia are obligate intracellular, gram-negative, arthropod-borne pathogens of humans and other mammals. The life-threatening character of diseases caused by many Rickettsia species and the lack of reliable protective vaccine against rickettsioses strengthens the importance of identifying new protein factors for the potential development of innovative therapeutic tools. Herein, we report the identification and characterization of a novel membrane-embedded retropepsin-like homologue, highly conserved in 55 Rickettsia genomes. Using R. conorii gene homologue RC1339 as our working model, we demonstrate that, despite the low overall sequence similarity to retropepsins, the gene product of rc1339 APRc (for Aspartic Protease from Rickettsia conorii is an active enzyme with features highly reminiscent of this family of aspartic proteases, such as autolytic activity impaired by mutation of the catalytic aspartate, accumulation in the dimeric form, optimal activity at pH 6, and inhibition by specific HIV-1 protease inhibitors. Moreover, specificity preferences determined by a high-throughput profiling approach confirmed common preferences between this novel rickettsial enzyme and other aspartic proteases, both retropepsins and pepsin-like. This is the first report on a retropepsin-like protease in gram-negative intracellular bacteria such as Rickettsia, contributing to the analysis of the evolutionary relationships between the two types of aspartic proteases. Additionally, we have also shown that APRc is transcribed and translated in R. conorii and R. rickettsii and is integrated into the outer membrane of both species. Finally, we demonstrated that APRc is sufficient to catalyze the in vitro processing of two conserved high molecular weight autotransporter adhesin/invasion proteins, Sca5/OmpB and Sca0/OmpA, thereby suggesting the participation of this enzyme in a relevant proteolytic pathway in rickettsial life-cycle. As a

  7. Molecular detection of Rickettsia typhi in cats and fleas.

    Directory of Open Access Journals (Sweden)

    Maria Mercedes Nogueras

    Full Text Available BACKGROUND: Rickettsiatyphi is the etiological agent of murine typhus (MT, a disease transmitted by two cycles: rat-flea-rat, and peridomestic cycle. Murine typhus is often misdiagnosed and underreported. A correct diagnosis is important because MT can cause severe illness and death. Our previous seroprevalence results pointed to presence of human R. typhi infection in our region; however, no clinical case has been reported. Although cats have been related to MT, no naturally infected cat has been described. The aim of the study is to confirm the existence of R. typhi in our location analyzing its presence in cats and fleas. METHODOLOGY/PRINCIPAL FINDINGS: 221 cats and 80 fleas were collected from Veterinary clinics, shelters, and the street (2001-2009. Variables surveyed were: date of collection, age, sex, municipality, living place, outdoor activities, demographic area, healthy status, contact with animals, and ectoparasite infestation. IgG against R. typhi were evaluated by indirect immunofluorescence assay. Molecular detection in cats and fleas was performed by real-time PCR. Cultures were performed in those cats with positive molecular detection. Statistical analysis was carried out using SPSS. A p < 0.05 was considered significant. Thirty-five (15.8% cats were seropositive. There were no significant associations among seropositivity and any variables. R. typhi was detected in 5 blood and 2 cultures. High titres and molecular detection were observed in stray cats and pets, as well as in spring and winter. All fleas were Ctenocephalides felis. R. typhi was detected in 44 fleas (55%, from shelters and pets. Co-infection with R. felis was observed. CONCLUSIONS: Although no clinical case has been described in this area, the presence of R. typhi in cats and fleas is demonstrated. Moreover, a considerable percentage of those animals lived in households. To our knowledge, this is the first time R. typhi is detected in naturally infected cats.

  8. Antibodies to Rickettsia rickettsii, Rickettsia typhi, Coxiella burnetii, Bartonella henselae, Bartonella quintana, and Ehrlichia chaffeensis among healthy population in Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Gonçalves da Costa

    2005-12-01

    Full Text Available Rickettsial diseases except those belonging to spotted fever group rickettsioses are poorly studied in South America particularly in Brazil where few epidemiological reports have been published. We describe a serosurvey for Rickettsia rickettsii, R. typhi, Coxiella burnetii, Bartonella henselae, B. quintana, and Ehrlichia chaffeensis in 437 healthy people from a Brazilian rural community. The serum samples were tested by indirected micro-immunoflourescence technique and a cutoff titer of 1:64 was used. The seroprevalence rates for R. rickettsii, R. typhi, C. burnetii, B. henselae, B. quintana, and E. chaffeensis were respectively 1.6% (7 samples; 1.1% (5 samples; 3.9% (17 samples; 13.7% (60 samples; 12.8% (56 samples, and 10.5% (46 samples. Frequent multiple/cross-reactivity was observed in this study. Age over 40 years old, urban profession, and rural residence were significantly associated with some but not all infections rate. Low seropositivity rates for R. rickettsii, R. typhi, and C. burnetii contrasted with higher rates of seropositivity for B. quintana, B. henselae, and E. chaffeensis. These results show that all tested rickettsial species or antigenically closely related possible exist in this particular region.

  9. Prevalence of Rickettsia raoultii in Dermacentor marginatus ticks from wild boars in France%法国野猪中Rickettsia raoultii的流行

    Institute of Scientific and Technical Information of China (English)

    曲芬; Jean Luc Llabers; Oleg Mediannikov; Jean-Marc Rolain

    2010-01-01

    目的 调查和鉴定法国野猪身上Rickettsia raoultii的流行情况以及野猪作为贮存宿主所起的作用.方法 收集法国2007年9月到11月的野猪身上的边缘革蜱163只.应用柠檬酸合成酶基因和外膜蛋白基因进行实时定量PCR、普通PCR技术及序列分析方法检测立克次体.结果 113只(69.3%)边缘革蜱立克次检测阳性.进一步鉴定为斑点热的两类病原,其中R.raoultii占57.5%(存在于65只蜱中)和R.slovaca占42.5%(存在于48只蜱中).结论 证明R.raoultii是野猪身上边缘革蜱的主要病原,边缘革蜱中感染率较高.应警惕野猪对立克次体的传播作用.

  10. Naturalistic Elements in Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    刘艳晖

    2007-01-01

    @@ Theodore Dreiser is considered to be a controversial writer.His first novel.Sister Carrie makes a new way of presenting re-ality.This paper discusses the naturalistic elements from the de-tailed description of the environment in that society.

  11. Rickettsia typhi IN RODENTS AND R. felis IN FLEAS IN YUCATÁN AS A POSSIBLE CAUSAL AGENT OF UNDEFINED FEBRILE CASES

    Directory of Open Access Journals (Sweden)

    Gaspar PENICHE-LARA

    2015-04-01

    Full Text Available Rickettsia typhi is the causal agent of murine typhus; a worldwide zoonotic and vector-borne infectious disease, commonly associated with the presence of domestic and wild rodents. Human cases of murine typhus in the state of Yucatán are frequent. However, there is no evidence of the presence of Rickettsia typhi in mammals or vectors in Yucatán. The presence of Rickettsia in rodents and their ectoparasites was evaluated in a small municipality of Yucatán using the conventional polymerase chain reaction technique and sequencing. The study only identified the presence of Rickettsia typhi in blood samples obtained from Rattus rattus and it reported, for the first time, the presence of R. felis in the flea Polygenis odiosus collected from Ototylomys phyllotis rodent. Additionally, Rickettsia felis was detected in the ectoparasite Ctenocephalides felis fleas parasitizing the wild rodent Peromyscus yucatanicus. This study’s results contributed to a better knowledge of Rickettsia epidemiology in Yucatán.

  12. High prevalence of Rickettsia africae variants in Amblyomma variegatum ticks from domestic mammals in rural western Kenya: implications for human health.

    Science.gov (United States)

    Maina, Alice N; Jiang, Ju; Omulo, Sylvia A; Cutler, Sally J; Ade, Fredrick; Ogola, Eric; Feikin, Daniel R; Njenga, M Kariuki; Cleaveland, Sarah; Mpoke, Solomon; Ng'ang'a, Zipporah; Breiman, Robert F; Knobel, Darryn L; Richards, Allen L

    2014-10-01

    Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africae-genotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya.

  13. First detections of Rickettsia helvetica and R. monacensis in ectoparasitic mites (Laelapidae and Trombiculidae) infesting rodents in south-western Slovakia.

    Science.gov (United States)

    Miťková, Katarína; Berthová, Lenka; Kalúz, Stanislav; Kazimírová, Mária; Burdová, Lenka; Kocianová, Elena

    2015-07-01

    Information on circulation of rickettsiae between small mammals and their ectoparasitic mites is scarce. In this study, we investigated infestation rates of rodents with mites in some areas of SW Slovakia and the role of mites as possible vectors of pathogenic rickettsiae. A total of 615 rodents of five species were caught during 2010-2012. All individuals were examined for ectoparasites which resulted in 2821 mites belonging to three species of Laelapidae and six species of Trombiculidae. The most common Laelapidae species was Laelaps agilis (81.25 %), followed by Haemogamasus nidi, and Eulaelaps stabularis. Hirsutiella zachvatkini (16.52 %) was the dominant species of the family Trombiculidae. DNA extracted from rodent blood and ectoparasitic mites was examined for the presence of rickettsiae by PCR. By pooling mites, 345 pool samples were created, of which 112 (32.46 %) were found to be positive for the rickettsial DNA. From 487 examined rodent blood samples, rickettsial DNA was found in 46 (9.44 %). Sequencing DNA from the positive blood samples and mites revealed the identity of Rickettsia helvetica and Rickettsia monacensis. The results of the study suggest that ectoparasitic mites may be reservoirs as well as vectors of some pathogenic rickettsiae.

  14. Preliminary research on the distribution and transmission efficiency of Rickettsia, an endosymbiont of whitefly Bemisia tabaci%烟粉虱内共生菌 Rickettsia 在植物体内的分布及转移效率初探

    Institute of Scientific and Technical Information of China (English)

    安璇; 李翌菡; 李绍建; 郭长飞; 任顺祥; 邱宝利

    2015-01-01

    【目的】检测 Q 型烟粉虱 Bemisia tabaci (Gennadius)体内 Rickettsia 的感染情况,研究分析Rickettsia 共生菌经烟粉虱传入豇豆植物后的分布、转移效率等。【方法】以 Q 型烟粉虱为实验材料,利用常规 PCR 及荧光原位杂交技术(FISH),检测了烟粉虱体内 Rickettsia 的感染率,以及 Rickettsia 传入豇豆植物体内后的存留情况。【结果】 Q 型烟粉虱可以通过取食将 Rickettsia 传至豇豆植株内;接虫数量与 Rickettsia传入效率及其在取食部位相邻的下部叶片中检测到的起始时间呈负相关;Rickettsia 经烟粉虱取食传入豇豆叶片后,集中分布在叶片的韧皮部筛管中;基于16S rRNA 的系统发育分析结果表明,Q 型烟粉虱体内的Rickettsia 与经取食传入豇豆叶片的 Rickettsia 高度同源。【结论】 Rickettsia 可以通过烟粉虱的取食传入植物体内,并且可以在相邻叶片之间转移传播,Rickettsia 在由寄主昆虫向植株传播过程中高度保守。%Objectives] To detect the infection of Bemisia tabaci by Rickettsia, and the distribution and dissemination of Rickettsia after its transmission to cowpea leaves through whitefly feeding. [Methods] Infection of the B. tabaci Q biotype by Rickettsia, and its persistence in cowpea plants, were detected by PCR and fluoresent in situ hybridization (FISH). [Results] The distribution of Rickettsia was limited to the phloem vessels of cowpea leaves, Rickettsia could move along the vessels between different leaves, and its efficiency of dissemination was highly related to the initial population size of Rickettsia-positive B. tabaci individuals that fed on the cowpea leaves. Phylogenetic analysis based on 16S rRNA variation showed that Rickettsia in cowpea plants and whiteflies was 100% identical. [Conclusion] Rickettsia can be horizontally transmitted to cowpea plants through the feeding of the B. tabaci Q biotype and little genetic variation

  15. Candidatus Rickettsia andeanae, a spotted fever group agent infecting Amblyomma parvum ticks in two Brazilian biomes.

    Science.gov (United States)

    Nieri-Bastos, Fernanda Aparecida; Lopes, Marcos Gomes; Cançado, Paulo Henrique Duarte; Rossa, Giselle Ayres Razera; Faccini, João Luiz Horácio; Gennari, Solange Maria; Labruna, Marcelo Bahia

    2014-04-01

    Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul) and from horses in the Cerrado biome (state of Piauí) in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR) targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63) and 66.7% (2/3) of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil.

  16. Molecular Detection of Rickettsia felis in Humans, Cats, and Cat Fleas in Bangladesh, 2013-2014.

    Science.gov (United States)

    Ahmed, Rajib; Paul, Shyamal Kumar; Hossain, Muhammad Akram; Ahmed, Salma; Mahmud, Muhammad Chand; Nasreen, Syeda Anjuman; Ferdouse, Faria; Sharmi, Rumana Hasan; Ahamed, Farid; Ghosh, Souvik; Urushibara, Noriko; Aung, Meiji Soe; Kobayashi, Nobumichi

    2016-05-01

    High prevalence of Rickettsia felis in patients with fever of unknown origin was revealed in the north-central Bangladesh from 2012 to 2013. Subsequently, in this study, prevalence of R. felis in cats and cat fleas (Ctenocephalides felis), together with febrile patients, was studied by PCR detection of 17 kDa antigen gene and DNA sequencing. R. felis was detected in 28% (28/100) and 21% (14/68) of cat blood and cat flea samples, respectively, whereas 42% (21/50) of patients were positive for R. felis. R. felis-positive cat fleas were detected at significantly higher rate on R. felis-positive cats. The results suggested a potential role of cats and cat fleas for transmission of R. felis to humans in Bangladesh.

  17. A confirmed case of Rickettsia parkeri infection in a traveler from Uruguay.

    Science.gov (United States)

    Portillo, Aránzazu; García-García, Concepción; Sanz, M Mercedes; Santibáñez, Sonia; Venzal, José M; Oteo, José A

    2013-12-01

    The first confirmed case of Rickettsia parkeri infection in Uruguay is reported. To date, in South America, molecularly confirmed cases of human infection have been found in Argentina and probably, Brazil. Our patient returned to Spain after a 7-day trip to Colonia Suiza (Southwestern Uruguay). He presented fever (39°C), chills, and two eschars (tache noire-like) surrounded by an indurated, erythematous halo on the inner side of the left ankle besides a maculopapular rash on the legs. After treatment with doxycycline for 7 days, he fully recovered. R. parkeri infection was diagnosed by molecular-based detection of the microorganism in a swab specimen of the eschar. Diagnosis was supported by seroconversion between acute- and convalescent-phase sera specimens.

  18. Detection and identification of Anaplasma phagocytophilum, Borrelia burgdorferi, and Rickettsia helvetica in Danish Ixodes ricinus ticks

    DEFF Research Database (Denmark)

    Skarphédinsson, Sigurdur; Lyholm, Birgitte Fjendbo; Ljungberg, Marianne

    2007-01-01

    Jutland and Funen, while 11% were positive for Borrelia burgdorferi. The Borrelia genotype B. afzelii was most prevalent, followed by B. valaisiana, B. burgdorferi s.s. and B. garinii.A. phagocytophilum was found in 14.5% of nymphs and 40.5% of adult ticks, while Borrelia was found in 13% of nymphs and 8......Borreliosis is an endemic infection in Denmark. Recent serosurveys have indicated that human anaplasmosis may be equally common. The aim of this study was to look for Anaplasma phagocytophilum and related pathogens in Ixodes ricinus ticks and estimate their prevalence, compared to Borrelia, using......% of adult ticks. The difference in prevalence between Anaplasma and Borrelia in adult ticks supports the idea that their maintenance cycles in nature may be different. Ticks were also infected with Rickettsia helvetica. Our study indicates that A. phagocytophilum prevalence in ticks in Denmark is as high...

  19. Spotted fever group rickettsiae in ticks from the Masai Mara region of Kenya.

    Science.gov (United States)

    Macaluso, Kevin R; Davis, Jon; Alam, Uzma; Korman, Amy; Rutherford, Jeremiah S; Rosenberg, Ronald; Azad, Abdu F

    2003-05-01

    We have identified for the first time Rickettsia africae, and the ticks that harbored them, in Kenya. A total of 5,325 ticks were collected from vegetation, livestock, and wild animals during two field trips to southwestern Kenya. Most were immature forms (85.2%) belonging to the genera Amblyomma or Rhipicephalus. The adults also included representatives from the genus Boophilus. Ticks were assessed for rickettsial DNA by a polymerase chain reaction (PCR) using primers for the spotted fever group (SFG)-specific rickettsial outer membrane protein A (rompA) gene, and positive amplicons were sequenced. While none of the immature ticks tested positive by PCR, 15.8% of the adult Amblyomma variegatum and less than 1% of the Rhipicephalus spp. were SFG positive. Sequences of amplified products were identified as R. africae. These findings extend the known range of R. africae.

  20. Candidatus Rickettsia andeanae, a spotted fever group agent infecting Amblyomma parvum ticks in two Brazilian biomes

    Directory of Open Access Journals (Sweden)

    Fernanda Aparecida Nieri-Bastos

    2014-04-01

    Full Text Available Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul and from horses in the Cerrado biome (state of Piauí in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63 and 66.7% (2/3 of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil.

  1. Studies on rickettsia-like organism(RLO)disease of tropical marine pearl oyster--Epidemiologicai investigation of RLO disease in juvenile populations of maricultured Pinctada maxima

    Institute of Scientific and Technical Information of China (English)

    Xinzhong Wu; Dengfeng Li; Jinpei Pan; Jingbo Jiang

    2003-01-01

    The death which occurred in juvenile population was a severe problem in the course ofPinctada maxima artificial culture. With the methods of field investigation, histological study andstatistic analyses, the epidemiological study was carried out on the disease and death in juvenile popula-tions of Pinctada maxima in the Xinying Pearl Oyster Mariculture Farm of Lingao County (for the A,B and C batches of cultured juveniles hanged in the sea) and the Xincun Pearl Oyster Mariculture Farmof Lingshui County (for the D batch of cultured juvenile hanged in the pond), Hainan Province fromNovember 1993 to April 1995. The results show that the deaths which occurred in juvenile populations of Pinctada maxima pre-sented an outbreak pattern. The peak of mortality rates, in general, occurred in 4-to 6-month old pearloyster juveniles, and the mortality rates gradully declined with the extention of pearl oyster age after cul-turing 8 months. The correlation between the mortality rates of juvenile populations and mean bodylengths of juvenile populations show that the mortality rate become higher under 4 cm of mean bodylengths of juvenile population and become obvious declined over 5 cm of mean body lengths. The peak ofmortality rate occurred in 1 ~3 cm of mean body lengths. The results of histological observation showedthat rickettsia-like organism inclusions were common, histological widespread infective agent among ev-ery batches (A, B, C and D) of cultured juvenile populations. The mean severity indices (SI) of rick-ettsia-like organism (RLO) infection were positively correlated with mortality rates of juvenile popula-tions. After or within every peaks of RLO infection were all accompanied with the peaks of mortalityrates of host populations and the mortality rates declined with decreased RLO infection. So the evidencesof histological observation and epidemiology in this study indicated that rickettsia-like organism (RLO)may be as an important pathogenic organism of disease

  2. Identification of novel surface-exposed proteins of Rickettsia rickettsii by affinity purification and proteomics.

    Science.gov (United States)

    Gong, Wenping; Xiong, Xiaolu; Qi, Yong; Jiao, Jun; Duan, Changsong; Wen, Bohai

    2014-01-01

    Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is the most pathogenic member among Rickettsia spp. Surface-exposed proteins (SEPs) of R. rickettsii may play important roles in its pathogenesis or immunity. In this study, R. rickettsii organisms were surface-labeled with sulfo-NHS-SS-biotin and the labeled proteins were affinity-purified with streptavidin. The isolated proteins were separated by two-dimensional electrophoresis, and 10 proteins were identified among 23 protein spots by electrospray ionization tandem mass spectrometry. Five (OmpA, OmpB, GroEL, GroES, and a DNA-binding protein) of the 10 proteins were previously characterized as surface proteins of R. rickettsii. Another 5 proteins (Adr1, Adr2, OmpW, Porin_4, and TolC) were first recognized as SEPs of R. rickettsii herein. The genes encoding the 5 novel SEPs were expressed in Escherichia coli cells, resulting in 5 recombinant SEPs (rSEPs), which were used to immunize mice. After challenge with viable R. rickettsii cells, the rickettsial load in the spleen, liver, or lung of mice immunized with rAdr2 and in the lungs of mice immunized with other rSEPs excluding rTolC was significantly lower than in mice that were mock-immunized with PBS. The in vitro neutralization test revealed that sera from mice immunized with rAdr1, rAdr2, or rOmpW reduced R. rickettsii adherence to and invasion of vascular endothelial cells. The immuno-electron microscopic assay clearly showed that the novel SEPs were located in the outer and/or inner membrane of R. rickettsii. Altogether, the 5 novel SEPs identified herein might be involved in the interaction of R. rickettsii with vascular endothelial cells, and all of them except TolC were protective antigens.

  3. Rickettsia slovaca in immature Dermacentor marginatus and tissues from Apodemus spp. in the northern Apennines, Italy.

    Science.gov (United States)

    Martello, Elisa; Selmi, Marco; Ragagli, Charlotte; Ambrogi, Cecilia; Stella, Maria Cristina; Mannelli, Alessandro; Tomassone, Laura

    2013-12-01

    Immature Dermacentor marginatus ticks and tissues from small rodents were tested for infection with Rickettsia slovaca in the northern Apennines, Lucca Province, where tick-borne lymphadenopathy (TIBOLA) was previously reported in people. Prevalence of infestation with D. marginatus was 30.5% (n=131, 95% CI: 22.8-39.2%) in Apodemus spp. and 26.5% (n=34, 95% CI: 12.9-44.4%) in Myodes glareolus, which were captured during 1980 trap nights in 2009 and 2010. Rickettsia slovaca was identified by polymerase chain reaction, targeting the gltA and OmpA genes, in ear biopsies from 8 out of 37 tested Apodemus (22%, 95% CI: 9.8-38.2%), but not from 9 M. glareolus. The prevalence of R. slovaca in D. marginatus feeding on Apodemus spp. was 53% in larvae (n=51, 95% CI: 38.5-67.1%) and 47.5% in nymphs (n=59, 95% CI: 34.3-60.9%). No larvae (0.0%, 95% CI: 0-36.9%), but one nymph removed from M. glareolus was positive (10%, 95% CI: 0.3-44.5%). Prevalence of R. slovaca in host-seeking D. marginatus larvae, collected in the same area, was 42% (n=38; 95% CI: 26.3-59.2%). Prevalence of R. slovaca was greater in larvae feeding on PCR-positive Apodemus than in those feeding on negative mice (78.6% vs. 37.1%). Furthermore, levels of infestation with D. marginatus larvae were greater for R. slovaca-positive mice. The infection of Apodemus spp. was probably the result of repeated bites by transovarially infected larvae. On the other hand, the finding of R. slovaca in mice tissues would be compatible with transmission from these hosts to feeding D. marginatus. Based on such a hypothesis, the most heavily infested Apodemus might play a role as amplifiers of the infection.

  4. Identification of novel surface-exposed proteins of Rickettsia rickettsii by affinity purification and proteomics.

    Directory of Open Access Journals (Sweden)

    Wenping Gong

    Full Text Available Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is the most pathogenic member among Rickettsia spp. Surface-exposed proteins (SEPs of R. rickettsii may play important roles in its pathogenesis or immunity. In this study, R. rickettsii organisms were surface-labeled with sulfo-NHS-SS-biotin and the labeled proteins were affinity-purified with streptavidin. The isolated proteins were separated by two-dimensional electrophoresis, and 10 proteins were identified among 23 protein spots by electrospray ionization tandem mass spectrometry. Five (OmpA, OmpB, GroEL, GroES, and a DNA-binding protein of the 10 proteins were previously characterized as surface proteins of R. rickettsii. Another 5 proteins (Adr1, Adr2, OmpW, Porin_4, and TolC were first recognized as SEPs of R. rickettsii herein. The genes encoding the 5 novel SEPs were expressed in Escherichia coli cells, resulting in 5 recombinant SEPs (rSEPs, which were used to immunize mice. After challenge with viable R. rickettsii cells, the rickettsial load in the spleen, liver, or lung of mice immunized with rAdr2 and in the lungs of mice immunized with other rSEPs excluding rTolC was significantly lower than in mice that were mock-immunized with PBS. The in vitro neutralization test revealed that sera from mice immunized with rAdr1, rAdr2, or rOmpW reduced R. rickettsii adherence to and invasion of vascular endothelial cells. The immuno-electron microscopic assay clearly showed that the novel SEPs were located in the outer and/or inner membrane of R. rickettsii. Altogether, the 5 novel SEPs identified herein might be involved in the interaction of R. rickettsii with vascular endothelial cells, and all of them except TolC were protective antigens.

  5. Prevalence of antibodies against Rickettsia conorii, Babesia canis, Ehrlichia canis, and Anaplasma phagocytophilum antigens in dogs from the Stretto di Messina area (Italy).

    Science.gov (United States)

    Pennisi, Maria-Grazia; Caprì, Alessandra; Solano-Gallego, Laia; Lombardo, Gabriella; Torina, Alessandra; Masucci, Marisa

    2012-12-01

    The aims of this study were to determine the seroprevalence for Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum, and Babesia canis in outdoor-kennelled dogs (n=249) from the Stretto di Messina (Italy) and to compare seroprevalence in 2 public shelters and 4 privately-owned kennels where different tick-preventive measures were implemented in order to focus on the specific sanitary risk posed by public shelters in southern Italy for tick-borne pathogens. R. conorii (72%) and B. canis (70%) were the most prevalent infections when compared to E. canis (46%) and A. phagocytophilum (38%). Seroprevalence for R. conorii, E. canis, and A. phagocytophilum was significantly higher in public shelters than in private kennels. However, B. canis seropositivity was similar in both types of kennels. In addition, in private kennels where a regular ectocide treatment was carried out by means of spot-on devices, dogs did not present E. canis and A. phagocytophilum antibodies. One hundred fifty-one dogs out of 249 (61%) were seropositive to more than one pathogen with R. conorii and B. canis the most common ones. Coinfections were more frequently found in public-shelter dogs. This study demonstrated high seroprevalences against R. conorii, B. canis, E. canis, and A. phagocytophilum in kennelled dogs from both coastal sites of the Stretto di Messina and the importance of regular tick-bite prevention by means of individual spot-on devices.

  6. Natural history of tick-borne spotted fever in the USA. Susceptibility of small mammals to virulent Rickettsia rickettsii.

    Science.gov (United States)

    Burgdorfer, W; Friedhoff, K T; Lancaster, J L

    1966-01-01

    In the ecology of spotted fever rickettsiae, one of the as yet unsolved problems concerns the significance of small animals in the distribution of Rickettsia rickettsii in nature. In the Bitter Root Valley of western Montana, a great variety of rodents, rabbits and hares are known to serve as the preferred hosts for the immature stages of the vector tick, Dermacentor andersoni.The authors analyse the susceptibility of various species of small mammals to virulent R. rickettsii and evaluate their efficiency as sources of infection for larval ticks. The results demonstrate that meadow-mice, Columbian ground-squirrels, golden-mantled ground-squirrels, chipmunks and snowshoe hares (the latter to a lesser extent), when bitten by infected ticks, respond with rickettsiaemias of sufficient length and degree to infect normal larval D. andersoni. High infection rates were obtained in ticks that fed during periods of high rickettsial concentrations in the blood.

  7. Detection of Rickettsia tamurae DNA in ticks and wild boar (Sus scrofa leucomystax) skins in Shimane Prefecture, Japan.

    Science.gov (United States)

    Motoi, Yuta; Asano, Makoto; Inokuma, Hisashi; Ando, Shuji; Kawabata, Hiroki; Takano, Ai; Suzuki, Masatsugu

    2013-01-01

    We used 24 wild boars trapped from December 2009 to January 2010 and a further 65 from July 2010 to August 2010 in Misato Town, Shimane Prefecture, Japan. We collected blood, spleens, skins and ticks from the wild boars, which were examined for rickettsial infections using polymerase chain reaction (PCR) primers for the genes rickettsial 17-kDa antigen and citrate synthase (gltA). We amplified Rickettsia tamurae AT-1 DNA from the tick Amblyomma testudinarium and from wild boar skins where ticks attached. Antibodies against spotted fever group Rickettsia were detected in wild boar sera using immunofluorescence, whereas blood and spleen samples contained no rickettsial DNA. This study suggests that wild boars have a role as an amplifier and a transporter of A. testudinarium, which harbor R. tamurae. One case of R. tamurae infection in humans was reported in Shimane Prefecture. Therefore, R. tamurae infections in humans might increase, if wild boar populations and their habitats expand.

  8. Identification of Orientia tsutsugamushi,spotted fever group and typhus group Rickettsia by duplex and nested PCR methods

    Institute of Scientific and Technical Information of China (English)

    M-C Luan; D-Z Yu; L Tang; L-J Zhang

    2008-01-01

    Objective:To identify members of genera of rickettsia and O.tsutsugamushi simultaneously.Methods:Rapid and duplex and nested PCR methods have been established by designing primers based on the conserved re-gions of heat shock protein GroEL gene.345 mouse viscera samples including liver,spleen and kidney,96 Xe-nopsylla cheopis and 32 chiggers collected from Hongta areas of Yuxi city,Yunnan province were tested by the new PCR methods.Results:The result of the study showed that the new PCR methods could identify most members of genera -Rickettsia and Orientia simultaneously with 100% specificity and its sensitivity could test one copy per microliter.The results of detection prevalence of rickettsioses in mouse,flea and mites DNA sam-ples showed that the total rickettsia infection rate in mouse was 34.78% (120 /345).The total infection rates in R.typhi,O.t Karp and R.sibirica of mouse samples were 28.12% (97 /345),19.71% (68 /345)and 0. 29% (1 /345)respectively.Co-infection rates in R.typhi and O.t Karp of mouse samples were 13.33% (46 /345).O.t Karp type has been the main epidemic strain in these areas.Conclusion:We concluded that this PCR method could be used to detect multi-genera rickettsia simultaneously.Molecular evidences provided in this and previous studies strongly support that Hongta areas of Yuxi city are a natural focus for typhus and scrub typhus with the common occurrence of their confection.

  9. Serological prevalence study of exposure of cats and dogs in Launceston, Tasmania, Australia to spotted fever group rickettsiae.

    Science.gov (United States)

    Izzard, L; Cox, E; Stenos, J; Waterston, M; Fenwick, S; Graves, S

    2010-01-01

    A sero-epidemiological study of cats and dogs in the Launceston area of Tasmania, Australia was undertaken to determine the prevalence of antibodies to spotted fever group (SFG) rickettsiae. Results showed that 59% of cats and 57% of dogs were positive for antibodies, but there was no correlation between the animal's health and seropositivity at the time of testing, suggesting that rickettsial exposure is unrelated to ill-health in these two species of domestic animals.

  10. Diversity of Bartonella and Rickettsia spp. in Bats and Their Blood-Feeding Ectoparasites from South Africa and Swaziland.

    Science.gov (United States)

    Dietrich, Muriel; Tjale, Mabotse A; Weyer, Jacqueline; Kearney, Teresa; Seamark, Ernest C J; Nel, Louis H; Monadjem, Ara; Markotter, Wanda

    2016-01-01

    In addition to several emerging viruses, bats have been reported to host multiple bacteria but their zoonotic threats remain poorly understood, especially in Africa where the diversity of bats is important. Here, we investigated the presence and diversity of Bartonella and Rickettsia spp. in bats and their ectoparasites (Diptera and Siphonaptera) collected across South Africa and Swaziland. We collected 384 blood samples and 14 ectoparasites across 29 different bat species and found positive samples in four insectivorous and two frugivorous bat species, as well as their Nycteribiidae flies. Phylogenetic analyses revealed diverse Bartonella genotypes and one main group of Rickettsia, distinct from those previously reported in bats and their ectoparasites, and for some closely related to human pathogens. Our results suggest a differential pattern of host specificity depending on bat species. Bartonella spp. identified in bat flies and blood were identical supporting that bat flies may serve as vectors. Our results represent the first report of bat-borne Bartonella and Rickettsia spp. in these countries and highlight the potential role of bats as reservoirs of human bacterial pathogens.

  11. Diversity of Bartonella and Rickettsia spp. in Bats and Their Blood-Feeding Ectoparasites from South Africa and Swaziland.

    Directory of Open Access Journals (Sweden)

    Muriel Dietrich

    Full Text Available In addition to several emerging viruses, bats have been reported to host multiple bacteria but their zoonotic threats remain poorly understood, especially in Africa where the diversity of bats is important. Here, we investigated the presence and diversity of Bartonella and Rickettsia spp. in bats and their ectoparasites (Diptera and Siphonaptera collected across South Africa and Swaziland. We collected 384 blood samples and 14 ectoparasites across 29 different bat species and found positive samples in four insectivorous and two frugivorous bat species, as well as their Nycteribiidae flies. Phylogenetic analyses revealed diverse Bartonella genotypes and one main group of Rickettsia, distinct from those previously reported in bats and their ectoparasites, and for some closely related to human pathogens. Our results suggest a differential pattern of host specificity depending on bat species. Bartonella spp. identified in bat flies and blood were identical supporting that bat flies may serve as vectors. Our results represent the first report of bat-borne Bartonella and Rickettsia spp. in these countries and highlight the potential role of bats as reservoirs of human bacterial pathogens.

  12. Rickettsia parkeri Transmission to Amblyomma americanum by Cofeeding with Amblyomma maculatum (Acari: Ixodidae) and Potential for Spillover.

    Science.gov (United States)

    Wright, Chelsea L; Sonenshine, Daniel E; Gaff, Holly D; Hynes, Wayne L

    2015-09-01

    Amblyomma americanum (L.) is a human-biting ixodid tick distributed throughout much of the southeastern United States. Rickettsia parkeri is a member of the spotted fever group rickettsiae and causes a febrile illness in humans commonly referred to as "Tidewater spotted fever" or "R. parkeri rickettsiosis." Although the Gulf Coast tick, Amblyomma maculatum Koch, is the primary vector of R. parkeri, a small proportion of A. americanum have also been shown to harbor R. parkeri. The purpose of this investigation was to determine whether R. parkeri is spilling over into A. americanum in eastern Virginia and also to determine through laboratory experiments, whether A. americanum can acquire R. parkeri by cofeeding alongside infected ticks. Of 317 wild-caught, flat adult A. americanum tested from 29 counties and independent cities in coastal Virginia, a single female A. americanum was positive for R. parkeri, suggesting that R. parkeri is spilling over into this species, but at very low rates (Rickettsia amblyommii, however, were less likely to acquire R. parkeri, suggesting that infection with R. amblyommii may prevent R. parkeri from establishing infection in A. americanum.

  13. Molecular characterization of Rickettsia massiliae and Anaplasma platys infecting Rhipicephalus sanguineus ticks and domestic dogs, Buenos Aires (Argentina).

    Science.gov (United States)

    Cicuttin, Gabriel L; Brambati, Diego F; Rodríguez Eugui, Juan I; Lebrero, Cecilia González; De Salvo, María N; Beltrán, Fernando J; Gury Dohmen, Federico E; Jado, Isabel; Anda, Pedro

    2014-09-01

    Rickettsioses, ehrlichioses and anaplasmoses are emerging diseases that are mainly transmitted by arthropods and that affect humans and animals. The aim of the present study was to use molecular techniques to detect and characterize those pathogens in dogs and ticks from Buenos Aires city. We studied 207 Rhipicephalus sanguineus ticks and 52 canine blood samples from poor neighborhoods of Buenos Aires city. The samples were molecularly screened for the genera Rickettsia, Ehrlichia, and Anaplasma by PCR and sequencing. DNA of Rickettsia massiliae (3.4%) and Anaplasma platys (13.5%) was detected in ticks and blood samples, respectively. For characterization, the positive samples were subjected to amplification of a fragment of the 190-kDa outer membrane protein gene (spotted fever group rickettsiae) and a fragment of the groESL gene (specific for A. platys). A phylogenetic tree was constructed using the neighbor-joining method, revealing that the sequences were closely related to those of strains from other geographic regions. The results indicate that human and animal pathogens are abundant in dogs and their ticks in Buenos Aires city and portray the potentially high risk of human exposure to infection with these agents, especially in poor neighborhoods, where there is close contact with animals in an environment of poor health conditions.

  14. Rickettsia parkeri: a Rickettsial pathogen transmitted by ticks in endemic areas for spotted fever rickettsiosis in southern Uruguay.

    Science.gov (United States)

    Venzal, José M; Estrada-Peña, Agustín; Portillo, Aránzazu; Mangold, Atilio J; Castro, Oscar; De Souza, Carlos G; Félix, María L; Pérez-Martínez, Laura; Santibánez, Sonia; Oteo, José A

    2012-01-01

    At first Rickettsia conorii was implicated as the causative agent of spotted fever in Uruguay diagnosed by serological assays. Later Rickettsia parkeri was detected in human-biting Amblyomma triste ticks using molecular tests. The natural vector of R. conorii, Rhipicephalus sanguineus, has not been studied for the presence of rickettsial organisms in Uruguay. To address this question, 180 R. sanguineus from dogs and 245 A. triste from vegetation (flagging) collected in three endemic localities were screened for spotted fever group (SFG) rickettsiosis in southern Uruguay. Tick extracted DNA pools were subjected to PCR using primers which amplify a fragment of the rickettsial gltA gene. Positive tick DNA pools with these primers were subjected to a second PCR round with primers targeting a fragment of the ompA gene, which is only present in SFG rickettsiae. No rickettsial DNA was detected in R. sanguineus. However, DNA pools of A. triste were found to be positive for a rickettsial organism in two of the three localities, with prevalences of 11.8% to 37.5% positive pools. DNA sequences generated from these PCR-positive ticks corresponded to R. parkeri. These findings, joint with the aggressiveness shown by A. triste towards humans, support previous data on the involvement of A. triste as vector of human infections caused by R. parkeri in Uruguay.

  15. A survey for spotted fever group rickettsiae and ehrlichiae in Amblyomma variegatum from St. Kitts and Nevis.

    Science.gov (United States)

    Kelly, Patrick J; Fournier, Pierre-Edouard; Parola, Philippe; Raoult, Didier

    2003-07-01

    Eighty-nine Amblyomma variegatum ticks were collected from the islands of St. Kitts and Nevis in the Caribbean and preserved in 70% ethanol or local rum. After being washed in sterile water, their DNA was extracted and analyzed by a polymerase chain reaction (PCR) for DNA of spotted fever group rickettsiae and ehrlichiae. None of the tested ticks was positive in a PCR assay using the primers 16S EHRD and 16S EHRR for the 16S rRNA gene of Ehrlichia spp.. Forty-one percent of the A. variegatum (36 of 89 of which 34 [47%] of 72 were adult males, 2 (13%) of 16 were adult females, and 0 (0%) of 1 were nymphs) were positive in a PCR assay using the primer pair 190-70 and 190-701 for the outer membrane protein A (ompA) gene of spotted fever group rickettsiae. All PCR amplification products obtained had 100% sequence homology with Rickettsia africae, the agent of African tick-bite fever.

  16. Rickettsia parkeri: a Rickettsial pathogen transmitted by ticks in endemic areas for spotted fever rickettsiosis in southern Uruguay

    Directory of Open Access Journals (Sweden)

    José M. Venzal

    2012-06-01

    Full Text Available At first Rickettsia conorii was implicated as the causative agent of spotted fever in Uruguay diagnosed by serological assays. Later Rickettsia parkeri was detected in human-biting Amblyomma triste ticks using molecular tests. The natural vector of R. conorii, Rhipicephalus sanguineus, has not been studied for the presence of rickettsial organisms in Uruguay. To address this question, 180 R. sanguineus from dogs and 245 A. triste from vegetation (flagging collected in three endemic localities were screened for spotted fever group (SFG rickettsiosis in southern Uruguay. Tick extracted DNA pools were subjected to PCR using primers which amplify a fragment of the rickettsial gltA gene. Positive tick DNA pools with these primers were subjected to a second PCR round with primers targeting a fragment of the ompA gene, which is only present in SFG rickettsiae. No rickettsial DNA was detected in R. sanguineus. However, DNA pools of A. triste were found to be positive for a rickettsial organism in two of the three localities, with prevalences of 11.8% to 37.5% positive pools. DNA sequences generated from these PCR-positive ticks corresponded to R. parkeri. These findings, joint with the aggressiveness shown by A. triste towards humans, support previous data on the involvement of A. triste as vector of human infections caused by R. parkeri in Uruguay.

  17. High detection rate of Rickettsia africae in Amblyomma variegatum but low prevalence of anti-rickettsial antibodies in healthy pregnant women in Madagascar.

    Science.gov (United States)

    Keller, Christian; Krüger, Andreas; Schwarz, Norbert Georg; Rakotozandrindrainy, Raphael; Rakotondrainiarivelo, Jean Philibert; Razafindrabe, Tsiry; Derschum, Henri; Silaghi, Cornelia; Pothmann, Daniela; Veit, Alexandra; Hogan, Benedikt; May, Jürgen; Girmann, Mirko; Kramme, Stefanie; Fleischer, Bernhard; Poppert, Sven

    2016-02-01

    Tick-borne spotted fever group (SFG) rickettsioses are emerging infectious diseases in Sub-Saharan Africa. In Madagascar, the endemicity of tick-borne rickettsiae and their vectors has been incompletely studied. The first part of the present study was conducted in 2011 and 2012 to identify potential anthropophilic tick vectors for SFG rickettsiae on cattle from seven Malagasy regions, and to detect and characterize rickettsiae in these ticks. Amblyomma variegatum was the only anthropophilic tick species found on 262 cattle. Using a novel ompB-specific qPCR, screening for rickettsial DNA was performed on 111 A. variegatum ticks. Rickettsial DNA was detected in 96 of 111 ticks studied (86.5%). Rickettsia africae was identified as the only infecting rickettsia using phylogenetic analysis of ompA and ompB gene sequences and three variable intergenic spacers from 11 ticks. The second part of the study was a cross-sectional survey for antibodies against SFG rickettsiae in plasma samples taken from healthy, pregnant women at six locations in Madagascar, two at sea level and four between 450 and 1300m altitude. An indirect fluorescent antibody test with Rickettsia conorii as surrogate SFG rickettsial antigen was used. We found R. conorii-seropositives at all altitudes with prevalences between 0.5% and 3.1%. Our results suggest that A. variegatum ticks highly infected with R. africae are the most prevalent cattle-associated tick vectors for SFG rickettsiosis in Madagascar. Transmission of SFG rickettsiosis to humans occurs at different altitudes in Madagascar and should be considered as a relevant cause of febrile diseases.

  18. Population analyses of Amblyomma maculatum ticks and Rickettsia parkeri using single-strand conformation polymorphism.

    Science.gov (United States)

    Ferrari, Flavia A G; Goddard, Jerome; Caprio, Michael; Paddock, Christopher D; Mixson-Hayden, Tonya; Varela-Stokes, Andrea S

    2013-09-01

    Gulf Coast ticks, Amblyomma maculatum, and the zoonotic agents they transmit, Rickettsia parkeri, are expanding into areas in the United States where they were not previously reported, and are emerging threats for public and veterinary health. The dynamics of this tick-pathogen system and implications for disease transmission are still unclear. To assess genetic variation of tick and rickettsial populations, we collected adult A. maculatum from 10 sites in Mississippi, 4 in the northern, one in the central, and 5 in the southern part of the state. PCR amplicons from tick mitochondrial 16S rRNA and rickettsial ompA genes as well as 5 intergenic spacer regions were evaluated for genetic variation using single-strand conformation polymorphism analysis. Frequencies of the 4 tick 16S haplotypes were not significantly different among regions of Mississippi, but within sites there were differences in distribution that can be explained by high migration rates. Phylogenetically, one lineage of tick haplotypes was a species-poor sister group to remaining haplotypes in the species-rich sister group. No genetic variation was identified in any of the 6 selected gene targets of R. parkeri examined in the infected ticks, suggesting high levels of intermixing.

  19. Rickettsia-like organism infection in a freshwater cultured fish Ophiocephalus argus C.in China

    Institute of Scientific and Technical Information of China (English)

    GUO Qionglin; JIA Weizhang; HAN Xianpu; CAI Taozhen; GONG Xiaoning; SUN Xiaofeng

    2004-01-01

    From 2001 to 2002,a new and emergent infectious disease of Ophiocephalus argus occurred in a fishery in Hubei Province,China,with an incidence of 60%~70% and a mortality as high as 100%.The diseased fish showed an enlarged abdomen,the millet-like nodules in internal organs,and the swollen kidney which was composed of 5~10 sarcoma-like bodies in cream or gray-white colour or ulcerated into beandregs-like substance.Light microscopic observation revealed the basophilic or acidphilic inclusions in cytoplasm of the cells and the granulomas,a diffusive chronic inflammation in internal organs.Further analysis under an electron microscope indicated that the intracytoplasmic inclusions were rickettsia-like organisms (RLOs) that are either spherical or coccoid,with variable size,ranging from 0.5~1.5 μm in diameter,and enclosed within membrane-bound cytoplasmic vacuoles.RLO had a central nucleoid region with some fine filamentous structures and an electron-dense granule.Its cytoplasm contained abundant ribosomal bodies.Occasionally,RLO appeared to be divided by binary fission.RLOs were also observed in the homogenized tissue of infected fish.The results suggested that the death of cultured O.Argus was caused by RLO infection.

  20. Possible Role of Rickettsia felis in Acute Febrile Illness among Children in Gabon.

    Science.gov (United States)

    Mourembou, Gaël; Lekana-Douki, Jean Bernard; Mediannikov, Oleg; Nzondo, Sydney Maghendji; Kouna, Lady Charlene; Essone, Jean Claude Biteghe Bi; Fenollar, Florence; Raoult, Didier

    2015-10-01

    Rickettsia felis has been reported to be a cause of fever in sub-Saharan Africa, but this association has been poorly evaluated in Gabon. We assessed the prevalence of this bacterium among children Gabon; the locations were in urban, semiurban, and rural areas. DNA samples from 410 febrile children and 60 afebrile children were analyzed by quantitative PCR. Overall, the prevalence of R. felis among febrile and afebrile children was 10.2% (42/410 children) and 3.3% (2/60 children), respectively. Prevalence differed among febrile children living in areas that are urban (Franceville, 1.3% [1/77]), semiurban (Koulamoutou, 2.1% [3/141]), and rural (Lastourville, 11.2% [15/134]; Fougamou, 39.7% [23/58]). Furthermore, in a rural area (Fougamou), R. felis was significantly more prevalent in febrile (39.7% [23/58]) than afebrile children (5.0% [1/20]). Additional studies are needed to better understand the pathogenic role of R. felis in this part of the world.

  1. Transcriptional analysis of Rickettsia prowazekii invasion gene homolog (invA) during host cell infection.

    Science.gov (United States)

    Gaywee, Jariyanart; Radulovic, Suzana; Higgins, James A; Azad, Abdu F

    2002-11-01

    An invasion gene homolog, invA, of Rickettsia prowazekii has recently been identified to encode a member of the Nudix hydrolase subfamily which acts specifically on dinucleoside oligophosphates (Np(n)N; n >/= 5), a group of cellular signaling molecules known as alarmones. InvA is thought to enhance intracellular survival by regulating stress-induced toxic nucleotide levels during rickettsial infection. To further characterize the physiological function of InvA, the gene expression pattern during various stages of rickettsial intracellular growth was investigated. Using semiquantitative reverse transcription-PCR (RT-PCR) and real-time fluorescent probe-based quantitative RT-PCR, a differential expression profile of invA during rickettsial host cell infection was examined. The invA transcript temporarily increased during the early period of infection. Expression of rickettsial groEL, a molecular indicator of cellular stresses, was also shown to be upregulated during the early period of infection. Furthermore, invA was cotranscribed in a polycistronic message with rrp, a gene encoding the response regulator protein homolog, which is a part of a two-component signal transduction system. These results support our earlier findings that under such stress conditions dinucleoside oligophosphate pyrophosphatase may function as a buffer, enhancing rickettsial survival within the cytoplasm of a eukaryotic cell. The expression of rickettsial dinucleoside oligophosphate pyrophosphatase may be regulated by a part of the two-component signal transduction system similar to that described for response regulators in other bacterial systems.

  2. Fiebre manchada por rickettsias en el Delta del Paraná: Una enfermedad emergente Rickettsial spotted fever in the Paraná Delta: An emerging disease

    Directory of Open Access Journals (Sweden)

    Alfredo Seijo

    2007-12-01

    Full Text Available Se comunica un caso de fiebre manchada por rickettsia autóctono del delta del Paraná correspondiente a la provincia de Buenos Aires. Luego de cinco días de haber permanecido en una región cercana a la localidad de ingeniero Otamendi, partido de Campana, el paciente presentó un síndrome febril agudo caracterizado por hipertermia con escalofríos y sudoración, mialgias, cefalea, astenia y discreta odinofagia, seguido a las 72 horas por un exantema maculopapuloso congestivo con elementos purpúricos, de distribución universal. En la región preauricular izquierda se observaba una lesión papuloerosiva, producida cinco días antes de iniciada la fiebre por una garrapata adquirida en el lugar. El cuadro clínico remitió rápidamente con la administración de doxiciclina. Por inmunofluorescencia indirecta se identificaron anticuerpos reactivos contra el grupo de rickettsias causantes de fiebres manchadas (CDC, Atlanta, EE.UU.. Se realizan consideraciones sobre la especie de rickettsia, el vector involucrado y la posibilidad que la enfermedad fuera debida a Rickettsia parkeri.We describe a case of rickettsial spotted fever in the Paraná Delta region of Buenos Aires province in Argentina. The patient developed an acute febrile syndrome characterized by myalgias, headache, asthenia and moderate odynophagia, followed by a diffuse macular, papular, and purpuric exanthema. The patient had been bitten recently by a tick on the left preauricular region and an erosive papular lesion was evident at the bite site. An indirect immunofluorescence antibody assay identified antibodies reactive with spotted fever group rickettsiae in the patient's serum. The patient improved rapidly with doxycycline. Several considerations relating to the identity of the rickettsial species and tick vector are discussed, including the possibility that this patient's illness may have been caused by Rickettsia parkeri.

  3. Infections That Pets Carry (For Parents)

    Science.gov (United States)

    ... Your 1- to 2-Year-Old Infections That Pets Carry KidsHealth > For Parents > Infections That Pets Carry ... how to protect your family from infections. How Pets Spread Infections Like people, all animals carry germs . ...

  4. Detección de Rickettsia spp. en Garrapatas de Myrmecophaga tridactyla de Vida Libre en la Sabana Inundable de Casanare‚ Colombia -resumen-

    OpenAIRE

    César Rojano-Bolaño; R Ávila-Avilán; L Miranda-Cortés; V Contreras-Cogollo; Jorge Miranda-Regino; Laura Hernández-Fernández; Salim Mattar-Velilla; Santiago Monsalve-Buriticá; J Carrascal-Velásquez

    2014-01-01

    Las bacterias del género Rickettsia son organismos con distribución mundial‚ causantes de algunas enfermedades zoonóticas de gran importancia en salud pública. Sin embargo‚ en Colombia son pocos los estudios enfocados a conocer su distribución y los vectores involucrados. El objetivo de este estudio fue detectar la presencia de Rickettsia spp.‚ en garrapatas colectadas en nueve osos palmeros (Myrmecophaga tridactyla) de vida libre en el municipio de Pore‚ Casanare‚ entre los años 2013 y 2014....

  5. First report for the seasonal and annual prevalence of flea-borne bartonella from rodents and soricomorphs in the Republic of Korea.

    Science.gov (United States)

    Kim, Baek-Jun; Kim, Su-Jin; Kang, Jun-Gu; Ko, Sungjin; Won, Sohyun; Kim, Hyewon; Kim, Heung-Chul; Kim, Myung-Soon; Chong, Sung-Tae; Klein, Terry A; Lee, Sanghun; Chae, Joon-Seok

    2013-07-01

    Rodents and soricomorphs are animal hosts of fleas and associated zoonotic microbial pathogens. A total of 4,889 small mammals were collected from Gyeonggi and Gangwon Provinces, Republic of Korea, from 2008 through 2010, including: Apodemus agrarius (4,122, 84.3%), followed by Crocidura lasiura (282, 5.8%), Microtus fortis (257, 5.3%), Myodes regulus (77, 1.6%), Micromys minutus (71, 1.5%), Mus musculus (63, 1.3%), and 4 other species (17, 0.3%). A total of 1,099 fleas belonging to 10 species and 7 genera were collected. Ctenophthalmus congeneroides (724, 65.9%) was the most commonly collected flea, followed by Stenoponia sidimi (301, 27.4%), Neopsylla bidentatiformis (29, 2.6%), and Rhadinopsylla insolita (25, 2.3%). The remaining species accounted for only 1.8% (20, range 1-6) of all fleas collected. The 2 dominant flea species, C. congeneroides and S. sidimi, showed an inverse seasonal pattern, with higher populations of C. congeneroides from January-September, whereas S. sidimi was more frequently collected during October-December. The overall flea infestation rates (FIR) and flea indices (FI) were 14.1% and 0.22, respectively, and were highest during April-June (19.7% and 0.30, respectively). A total of 735 of the 1,099 fleas were assayed for the detection of Bartonella spp. by PCR using Bartonella-specific primers, of which 515 were positive for Bartonella, with an overall maximum likelihood estimate (MLE) of 700.7/1,000. The highest MLE values were observed during April-June (899.2) and July-September (936.2) trapping periods and, although lower, were similar for January-March (566.7) and October-December (574.1). C. congeneroides demonstrated high MLEs for all seasons (range 752.5-934.8), while S. sidimi was positive for Bartonella only during January-March (MLE=342.1) and October-December (MLE=497.2) collection periods. Continued long-term surveillance of small mammals and associated ectoparasites is needed to improve our understanding of the prevalence of Bartonella spp. in fleas and the role of fleas in the zoonotic maintenance and transmission of Bartonella to humans.

  6. A Molecular survey of Anaplasma spp., Rickettsia spp., Ehrlichia canis and Babesia microti in foxes and fleas from Sicily.

    Science.gov (United States)

    Torina, A; Blanda, V; Antoci, F; Scimeca, S; D'Agostino, R; Scariano, E; Piazza, A; Galluzzo, P; Giudice, E; Caracappa, S

    2013-11-01

    Fleas (Insecta: Siphonaptera) are obligate bloodsucking insects, which parasitize birds and mammals, and are distributed throughout the world. Several species have been implicated in pathogen transmission. This study aimed to monitor red foxes and the fleas isolated from them in the Palermo and Ragusa provinces of Sicily, Italy, as these organisms are potential reservoirs and vectors of pathogens. Thirteen foxes (Vulpes vulpes) and 110 fleas were analysed by polymerase chain reaction (PCR) to detect DNA of the pathogens Ehrlichia canis, Babesia microti, Rickettsia spp., Anaplasma phagocytophilum, Anaplasma platys, Anaplasma marginale and Anaplasma ovis. In the foxes, A. ovis was detected in only one animal, whereas the prevalence of the E. canis pathogen was 31%. B. microti and Rickettsia spp. were not detected. Of all of the collected fleas, 75 belonged to the species Xenopsylla cheopis, 32 belonged to Ctenocephalides canis, two belonged to Ctenocephalides felis and one belonged to Cediopsylla inaequalis. In the fleas, the following pathogens were found: A. ovis (prevalence 25%), A. marginale (1%), A. phagocytophilum (1%), Rickettsia felis (2%) and E. canis (3%). X. cheopis was the flea species most frequently infected with Anaplasma, in particular A. ovis (33%), A. marginale (1%) and A. phagocytophilum (1%). Both C. felis exemplars were positive for R. felis. E. canis was found in the lone C. inaequalis and also in 3% of the X. cheopis specimens. No fleas were positive for B. microti or A. platys. As foxes often live in proximity to domestic areas, they may constitute potential reservoirs for human and animal parasites. Further studies should be performed on fleas to determine their vectorial capacity.

  7. Lyme borreliosis spirochetes and spotted fever group rickettsiae in ixodid ticks from Pianosa island, Tuscany Archipelago, Italy.

    Science.gov (United States)

    Tomassone, L; Grego, E; Auricchio, D; Iori, A; Giannini, F; Rambozzi, L

    2013-02-01

    A study on tick fauna and tick-borne pathogens was undertaken in Pianosa, an island in the Tuscany Archipelago that constitutes an important stopping and nesting point for migratory birds. Ticks were removed from feral cats and a few terrestrial birds, and host-seeking ticks were collected by dragging. A total of 89 ticks were found on animals: 57 Ixodes ventalloi Gil Collado, 1936 and 32 Ixodes acuminatus Neumann, 1901. Host-seeking ticks were 354 Hyalomma spp. larvae and 18 Hyalomma spp. adults, identified as Hyalomma marginatum C.L. Koch, 1844 (n=11) and 7 Hyalomma detritum Schulze, 1919 (n=7). A sample of adult ticks was subjected to molecular analyses to look for Rickettsia spp. and Borrelia burgdorferi sensu lato (s.l.). Sequence analysis of the 5S-23S intergenic spacer region and OspA gene of B. burgdorferi s.l.-positive samples showed the presence of Borrelia spielmanii (n=3; 3.7%, 95% confidence interval [CI] 0.08-10.4) and Borrelia valaisiana (n=13; 13.6%, 95% CI 7.0-23.0) in Ixodes ticks from cats and terrestrial birds. Ixodes spp. were also infected by Rickettsia helvetica (n=19; 23.4%, 95% CI 14.7-34.2). Finally, we detected Rickettsia aeschlimannii in 3 out of 12 host-seeking Hyalomma spp. adults tested (25%, 95% CI 5.5-57.2). Our study shows the presence of several tick-borne pathogens in Pianosa. Hyalomma spp. and Ixodes ticks other than I. ricinus seem to be involved in their epidemiological cycle, and birds could contribute to the pathogen dispersal along their migration routes. This is the first finding of B. spielmanii in Italy. We hypothesize the involvement of peridomestic rodents or hedgehogs in its maintenance in Pianosa.

  8. Rickettsiae induce microvascular hyperpermeability via phosphorylation of VE-cadherins: evidence from atomic force microscopy and biochemical studies.

    Directory of Open Access Journals (Sweden)

    Bin Gong

    Full Text Available The most prominent pathophysiological effect of spotted fever group (SFG rickettsial infection of microvascular endothelial cells (ECs is an enhanced vascular permeability, promoting vasogenic cerebral edema and non-cardiogenic pulmonary edema, which are responsible for most of the morbidity and mortality in severe cases. To date, the cellular and molecular mechanisms by which SFG Rickettsia increase EC permeability are largely unknown. In the present study we used atomic force microscopy (AFM to study the interactive forces between vascular endothelial (VE-cadherin and human cerebral microvascular EC infected with R. montanensis, which is genetically similar to R. rickettsii and R. conorii, and displays a similar ability to invade cells, but is non-pathogenic and can be experimentally manipulated under Biosafety Level 2 (BSL2 conditions. We found that infected ECs show a significant decrease in VE-cadherin-EC interactions. In addition, we applied immunofluorescent staining, immunoprecipitation phosphorylation assay, and an in vitro endothelial permeability assay to study the biochemical mechanisms that may participate in the enhanced vascular permeability as an underlying pathologic alteration of SFG rickettsial infection. A major finding is that infection of R. montanensis significantly activated tyrosine phosphorylation of VE-cadherin beginning at 48 hr and reaching a peak at 72 hr p.i. In vitro permeability assay showed an enhanced microvascular permeability at 72 hr p.i. On the other hand, AFM experiments showed a dramatic reduction in VE-cadherin-EC interactive forces at 48 hr p.i. We conclude that upon infection by SFG rickettsiae, phosphorylation of VE-cadherin directly attenuates homophilic protein-protein interactions at the endothelial adherens junctions, and may lead to endothelial paracellular barrier dysfunction causing microvascular hyperpermeability. These new approaches should prove useful in characterizing the antigenically

  9. A Brief Analysis of Sister Carrie's Character

    Science.gov (United States)

    Yu, Hanying

    2010-01-01

    Carrie is always dreaming while the rocking chair is rocking again and again, this is the deep impression on us after we read "Sister Carrie" which is the first novel of Theodore Dreiser. In this novel the protagonist Sister Carrie is a controversial person. This paper tries to analyze the character of Sister Carrie in order to find out…

  10. Molecular evidence for the presence of Rickettsia Felis in the feces of wild-living African apes.

    Directory of Open Access Journals (Sweden)

    Alpha Kabinet Keita

    Full Text Available BACKGROUND: Rickettsia felis is a common emerging pathogen detected in mosquitoes in sub-Saharan Africa. We hypothesized that, as with malaria, great apes may be exposed to the infectious bite of infected mosquitoes and release R. felis DNA in their feces. METHODS: We conducted a study of 17 forest sites in Central Africa, testing 1,028 fecal samples from 313 chimpanzees, 430 gorillas and 285 bonobos. The presence of rickettsial DNA was investigated by specific quantitative real-time PCR. Positive results were confirmed by a second PCR using primers and a probe targeting a specific gene for R. felis. All positive samples were sequenced. RESULTS: Overall, 113 samples (11% were positive for the Rickettsia-specific gltA gene, including 25 (22% that were positive for R. felis. The citrate synthase (gltA sequence and outer membrane protein A (ompA sequence analysis indicated 99% identity at the nucleotide level to R. felis. The 88 other samples (78% were negative using R. felis-specific qPCR and were compatible with R. felis-like organisms. CONCLUSION: For the first time, we detected R. felis in wild-living ape feces. This non invasive detection of human pathogens in endangered species opens up new possibilities in the molecular epidemiology and evolutionary analysis of infectious diseases, beside HIV and malaria.

  11. Prevalence of antibodies to spotted fever group Rickettsia spp. and Ehrlichia spp. in coyotes (Canis latrans) in Oklahoma and Texas, USA.

    Science.gov (United States)

    Starkey, Lindsay A; West, Misti D; Barrett, Anne W; Saucier, Jill M; O'Connor, Tom P; Paras, Kelsey L; Reiskind, Michael H; Reichard, Mason V; Little, Susan E

    2013-07-01

    Coyotes (Canis latrans) are commonly infested with ticks, including Amblyomma americanum, the predominant vector of Ehrlichia chaffeensis and Ehrlichia ewingii; Dermacentor variabilis, an important vector of Rickettsia rickettsii; and Amblyomma maculatum, a major vector of Rickettsia parkeri, a spotted fever group (SFG) Rickettsia. To determine the degree to which coyotes are infected with or exposed to tick-borne bacterial disease agents, serum samples collected from coyotes in Oklahoma and Texas were tested for antibodies reactive to R. rickettsii, Ehrlichia canis, E. chaffeensis, E. ewingii, Borrelia burgdorferi, and Anaplasma phagocytophilum by indirect fluorescent antibody (IFA) testing or enzyme-linked immunosorbent assay (ELISA). Of the coyotes tested, 60% (46/77) and 64% (47/74) had antibodies reactive to R. rickettsii and E. chaffeensis, respectively, on IFA. Additionally, 5% (4/77) had antibodies reactive to E. canis, but not B. burgdorferi or A. phagocytophilum, on SNAP(®) 4Dx(®) ELISA; subsequent serologic analysis by plate ELISA using species-specific peptides revealed antibodies to E. ewingii, E. canis, and E. chaffeensis in 46% (23/50), 18% (9/50), and 4% (2/50) of serum samples, respectively. Taken together, these data indicate that coyotes in this region are commonly exposed to SFG Rickettsia and E. ewingii and that further consideration of coyotes as a component of the maintenance cycle for these pathogens may be warranted.

  12. A serological and molecular survey of Babesia vogeli, Ehrlichia canis and Rickettsia spp. among dogs in the state of Maranhão, northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Andréa Pereira da Costa

    Full Text Available This study evaluated exposure and infection by tick-borne agents (Babesia vogeli, Ehrlichia canis and Rickettsia spp. in 172 dogs in rural areas and 150 dogs in urban areas of the municipality of Chapadinha, state of Maranhão, northeastern Brazil, using molecular and serological methods. Overall, 16.1% of the sampled dogs (52/322 were seroreactive to B. vogeli, with endpoint titers ranging from 40 to 640. For E. canis, 14.6% of the dogs (47/322 were seroreactive, with endpoint titers from 80 to 163,840. Antibodies reactive to at least one of the five species of Rickettsia were detected in 18.9% of the dogs (61/322, with endpoint titers ranging from 64 to 4,096. High endpoint titers were observed for Rickettsia amblyommii. Three (0.9% and nine (2.8% canine blood samples were PCR-positive for Babesia spp. and E. canis. The ticks collected from urban dogs were all Rhipicephalus sanguineus sensu lato, whereas the rural dogs were infested by R. sanguineus s.l, Amblyomma cajennense sensu lato and Amblyomma ovale. One A. ovale tick was found to be infected by Rickettsia bellii. This study provides an epidemiological background for controlling and preventing canine tick-borne diseases in a neglected region of Brazil.

  13. Molecular surveillance of spotted fever group rickettsioses in wildlife and detection of Rickettsia sibirica in a Topi (Damaliscus lunatus ssp. jimela in Kenya

    Directory of Open Access Journals (Sweden)

    David Ndeereh

    2017-01-01

    Full Text Available Spotted fever group rickettsioses are a group of tick-borne zoonotic diseases caused by intracellular bacteria of the genus Rickettsia. The diseases are widely reported amongst international travellers returning from most sub-Saharan Africa with fever, yet their importance in local populations largely remains unknown. Although this has started to change and recently there have been increasing reports of the diseases in livestock, ticks and humans in Kenya, they have not been investigated in wildlife. We examined the presence, prevalence and species of Rickettsia present in wildlife in two regions of Kenya with a unique human–wildlife–livestock interface. For this purpose, 79 wild animals in Laikipia County and 73 in Maasai Mara National Reserve were sampled. DNA extracted from blood was tested using the polymerase chain reaction (PCR to amplify the intergenic spacer rpmE-tRNAfMet and the citrate synthase-encoding gene gltA. Rickettsial DNA was detected in 2 of the 79 (2.5% animals in Laikipia and 4 of the 73 (5.5% in Maasai Mara. The PCR-positive amplicons of the gltA gene were sequenced to determine the detected Rickettsia species. This revealed Rickettsia sibirica in a Topi (Damaliscus lunatus ssp. jimela. This is the first report of spotted fever group rickettsioses in wildlife and the first to report R. sibirica in Kenya. The finding demonstrates the potential role of wild animals in the circulation of the diseases.

  14. Molecular analysis of Crimean-Congo hemorrhagic fever virus and Rickettsia in Hyalomma marginatum ticks removed from patients (Spain) and birds (Spain and Morocco), 2009-2015.

    Science.gov (United States)

    Palomar, Ana M; Portillo, Aránzazu; Mazuelas, David; Roncero, Lidia; Arizaga, Juan; Crespo, Ariñe; Gutiérrez, Óscar; Márquez, Francisco J; Cuadrado, Juan F; Eiros, José M; Oteo, José A

    2016-07-01

    Crimean-Congo hemorrhagic fever virus (CCHFV) was detected in Spain in 2010. The presence of CCHFV in Hyalomma marginatum ticks from migratory birds passing through Morocco during the spring migration strengthened the hypothesis of the arrival of infected ticks transported by birds to the Iberian Peninsula. Furthermore, Hyalomma species are vectors of bacterial infections such as spotted fever rickettsioses. CCHFV and Rickettsia were screened in Hyalomma ticks from Spain attached to patients (n=12) and birds (n=149). In addition, Rickettsia was investigated in 52 Hyalomma ticks from Morocco (previously reported as CCHFV-infected). No sample collected in Spain showed an infection with CCHFV. Two ticks removed from patients (16.7%), as well as 47 (31.5%) and 4 (7.7%) from birds, collected in Spain and Morocco respectively, were infected with Rickettsia aeschlimannii. Rickettsia sibirica subsp. mongolitimonae was also found in 2 ticks from birds collected in Spain (1.3%). The risk of CCHFV-infected ticks attached to migratory birds to reach the North of Spain is low. This study corroborates the presence of R. aeschlimannii in Spain and Morocco, and supports that H. marginatum can be a potential vector of R. sibirica subsp. mongolitimonae in the Iberian Peninsula.

  15. Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences

    Science.gov (United States)

    Nugnes, Francesco; Gebiola, Marco; Monti, Maurilia Maria; Gualtieri, Liberata; Giorgini, Massimo; Wang, Jianguo; Bernardo, Umberto

    2015-01-01

    The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed. PMID:25970681

  16. Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences.

    Directory of Open Access Journals (Sweden)

    Francesco Nugnes

    Full Text Available The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.

  17. Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences.

    Science.gov (United States)

    Nugnes, Francesco; Gebiola, Marco; Monti, Maurilia Maria; Gualtieri, Liberata; Giorgini, Massimo; Wang, Jianguo; Bernardo, Umberto

    2015-01-01

    The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.

  18. Molecular surveillance of spotted fever group rickettsioses in wildlife and detection of Rickettsia sibirica in a Topi (Damaliscus lunatus ssp. jimela) in Kenya.

    Science.gov (United States)

    Ndeereh, David; Thaiyah, Andrew; Muchemi, Gerald; Miyunga, Antoinette A

    2017-01-30

    Spotted fever group rickettsioses are a group of tick-borne zoonotic diseases caused by intracellular bacteria of the genus Rickettsia. The diseases are widely reported amongst international travellers returning from most sub-Saharan Africa with fever, yet their importance in local populations largely remains unknown. Although this has started to change and recently there have been increasing reports of the diseases in livestock, ticks and humans in Kenya, they have not been investigated in wildlife. We examined the presence, prevalence and species of Rickettsia present in wildlife in two regions of Kenya with a unique human-wildlife-livestock interface. For this purpose, 79 wild animals in Laikipia County and 73 in Maasai Mara National Reserve were sampled. DNA extracted from blood was tested using the polymerase chain reaction (PCR) to amplify the intergenic spacer rpmE-tRNAfMet and the citrate synthase-encoding gene gltA. Rickettsial DNA was detected in 2 of the 79 (2.5%) animals in Laikipia and 4 of the 73 (5.5%) in Maasai Mara. The PCR-positive amplicons of the gltA gene were sequenced to determine the detected Rickettsia species. This revealed Rickettsia sibirica in a Topi (Damaliscus lunatus ssp. jimela). This is the first report of spotted fever group rickettsioses in wildlife and the first to report R. sibirica in Kenya. The finding demonstrates the potential role of wild animals in the circulation of the diseases.

  19. SNP-based real-time pyrosequencing as a sensitive and specific tool for identification and differentiation of Rickettsia species in Ixodes ricinus ticks

    Directory of Open Access Journals (Sweden)

    Janecek Elisabeth

    2012-10-01

    Full Text Available Abstract Background Rickettsioses are caused by pathogenic species of the genus Rickettsia and play an important role as emerging diseases. The bacteria are transmitted to mammal hosts including humans by arthropod vectors. Since detection, especially in tick vectors, is usually based on PCR with genus-specific primers to include different occurring Rickettsia species, subsequent species identification is mainly achieved by Sanger sequencing. In the present study a real-time pyrosequencing approach was established with the objective to differentiate between species occurring in German Ixodes ticks, which are R. helvetica, R. monacensis, R. massiliae, and R. felis. Tick material from a quantitative real-time PCR (qPCR based study on Rickettsia-infections in I. ricinus allowed direct comparison of both sequencing techniques, Sanger and real-time pyrosequencing. Methods A sequence stretch of rickettsial citrate synthase (gltA gene was identified to contain divergent single nucleotide polymorphism (SNP sites suitable for Rickettsia species differentiation. Positive control plasmids inserting the respective target sequence of each Rickettsia species of interest were constructed for initial establishment of the real-time pyrosequencing approach using Qiagen’s PSQ 96MA Pyrosequencing System operating in a 96-well format. The approach included an initial amplification reaction followed by the actual pyrosequencing, which is traceable by pyrograms in real-time. Afterwards, real-time pyrosequencing was applied to 263 Ixodes tick samples already detected Rickettsia-positive in previous qPCR experiments. Results Establishment of real-time pyrosequencing using positive control plasmids resulted in accurate detection of all SNPs in all included Rickettsia species. The method was then applied to 263 Rickettsia-positive Ixodes ricinus samples, of which 153 (58.2% could be identified for their species (151 R. helvetica and 2 R. monacensis by previous custom

  20. A FEMINIST READING OF SISTER CARRIE

    Institute of Scientific and Technical Information of China (English)

    高陈科

    2011-01-01

    In the history of American literature, Sister Carrie has always been a controversial character. The critics regard Carrie either as a "fallen woman" or as a "new women". This thesis aims to offer a feminist reading of the image of Sister Carrie in the con

  1. 25 CFR 167.6 - Carrying capacities.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Carrying capacities. 167.6 Section 167.6 Indians BUREAU... Carrying capacities. (a) The Commissioner of Indian Affairs on June 26, 1943, promulgated the authorized carrying capacity for each land management district of the Navajo Reservation. (b) Recommended...

  2. 7 CFR 1437.402 - Carrying capacity.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Carrying capacity. 1437.402 Section 1437.402... Determining Coverage of Forage Intended for Animal Consumption § 1437.402 Carrying capacity. (a) CCC will establish a carrying capacity for all grazed forage present in the county for purposes of administering...

  3. Analysis of the Gut Microbes of the Chinese White Wax Scale Ericerus pela and Molecular Detection of Rickettsia%白蜡虫肠道微生物分析及立克次氏体分子检测

    Institute of Scientific and Technical Information of China (English)

    徐冬丽; 刘魏魏; 胡艳红; 杨璞; 陈晓鸣

    2012-01-01

    To understand the diversity of the gut microbes of Chinese white wax scale Ericerus pela, 16S rDNA clone library was constructed to analyze the gut microbes of the female E. pela adults. The results showed that, the gut of E. pela contained abundant of Rickettsia. Gut microbes Arsenophonus and Variovorax were also been identified. And Rickettsia was the main bacteria in gut of E. pela. The phylogenetic analysis of the 16S rDNA showed that, the Rickettsia from E. pela has close relationship with that of pea aphid Acyrthosiphon pisum. PCR amplification was performed using the specific primers for Rickettsia to detect infection in 30 male and 30 female individuals. The result showed that, the infected male and female were 24 and 12 respectively.

  4. Sister Carrie:A Material Pursuer

    Institute of Scientific and Technical Information of China (English)

    马春花

    2015-01-01

    Sister Carrie dramatized by Dreiser is totally a material pursuer. She is selfish and accumulates money in a crazy way. What she does inevitably centers on materials. Living with Drouet and later Hurstwood, Carrie gets what she wants and enjoys the luxurious life in an easy way. However, with the satisfaction of some of her desires, Carrie ’s desires grow and expand. With enough food and clothes, she needs luxury. Hurstwood’s failure in business leads Carrie to the stage and finally she makes a suc⁃cess and becomes a famous actress in Broadway. She gets more money, but her desires grow even higher. Nothing can satisfy her. In this essay, the author tries to analyze Carrie according to Freud’s and Guo Weilu’s theories and prove that Carrie is totally a material pursuer.

  5. 黑龙江口岸斑点热群立克次体调查研究%INVESTIGATION OF SPOTTED FEVER GROUP RICKETTSIA IN HEILONGJIANG PORT

    Institute of Scientific and Technical Information of China (English)

    鞠文东; 程成; 付维明; 王延禄; 呼满霞; 梁慧杰; 王红霞; 徐宁; 耿聪

    2015-01-01

    为了解黑龙江口岸地区斑点热群立克次体在人群、鼠类、蜱类中的分布特征,针对黑龙江省9个中俄边境口岸,采集出入境人群的血液样本215份、鼠类样本204份、蜱类样本188份,利用半巢式PCR方法对所有样本进行斑点热群立克次体特异性片段扩增,通过基因测序对斑点热群立克次体分型。结果在哈尔滨机场及嘉荫两个口岸的大仓鼠及小家鼠中检测到2例劳氏立克次体Rickettsia raoultii,为首次在黑龙江口岸鼠样本中检测出劳氏立克次体;在188份蜱样本中,检出斑点热群立克次体阳性样本101例,感染率达53.7%,其中劳氏立克次体89例,新塔拉塞维奇立克次体Candidatus Rickettsia tarasevichiae 11例,黑龙江立克次体Rickettsia heilongjiangii 1例,同样首次在黑龙江口岸全沟硬蜱中检测到新塔拉塞维奇立克次体。黑龙江中俄边境口岸开展SFGR的长期监测具有非常重要的公共卫生学意义。%To understand the distribution characteristics of spotted fever group Rickettsia in the residencies, rodents and ticks in Heilongjiang ports, total 9 port area along with Sino-Russian border were sampled to test the species and infection rates of spotted fever group Rickettsia from 188 ticks and 204 rodents.Moreover, 215 humans entry or exit from these ports were also include for screening the possible infection the rickettsia organisms under their permissions.Results from semi-nested PCR and sequences indicated that two Rickettsia raoultii detected in Cricetulus triton and Mus musculus Linnaeus respectively.None rickettsia organism were found in the human samples.While in ticks, 90 R.raoultii, 11 Candidatus Rickettsia tarasevichiae and 1 R.heilongiangii were found.The preliminary suggested the risk of emerged spotted fever pathogens in these areas and the necessary and urgent of long term monitoring on tick borne diseases.

  6. ENVIRONMENTAL CARRYING CAPACITY BASED ON SPATIAL PLANNING

    OpenAIRE

    Luthfi Muta'ali

    2013-01-01

    The aims of this research were to examine environmental carrying capacity analyzed based on aspects of spatial planning and eco-region. The result showed that Kulonprogo Regency has low value of environmental carrying capacity and can only support as much as 79.81% of its total population. Analysis of variance showed significant difference of environmental carrying capacity of protected and cultivated area. The main factor among 12 variables determining the degree of environmen...

  7. Carrie Chapman Catt and Woman Suffrage.

    Science.gov (United States)

    Hardesty, Carolyn, Ed.

    1989-01-01

    Most of the material for this issue of the "Goldfinch," which explores the life of Carrie Chapman Catt, came from the archives of the State Historical Society of Iowa. Carrie Chapman Catt (1859-1947) was an Iowan who advocated woman suffrage and spent 26 years actively working for that cause. The issue contains a biography of Catt, and…

  8. Bivalve carrying capacity in coastal ecosystems

    NARCIS (Netherlands)

    Dame, R.F.; Prins, T.C.

    1998-01-01

    carrying capacity of suspension feeding bivalves in 11 coastal and estuarine ecosystems is examined. Bivalve carrying capacity is defined in terms of water mass residence time, primary production time and bivalve clearance time. Turnover times for the 11 ecosystems are compared both two and three di

  9. Comments on the image of Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    张楠

    2016-01-01

    Thedore Oreiser was one of America's greatest writers and one of his famous masterpieces is Sister Carrie. the heroin of the novel was a country girl who struggled for success and finally became a movie star. Analysis on the image of Carrie is of practical significance to the country girls swarming into the city nowdays in our country.

  10. Prevalence, Distribution, and Development of an Ecological Niche Model of Dermacentor variabilis Ticks Positive for Rickettsia montanensis.

    Science.gov (United States)

    St John, Heidi K; Adams, Melissa L; Masuoka, Penny M; Flyer-Adams, Johanna G; Jiang, Ju; Rozmajzl, Patrick J; Stromdahl, Ellen Y; Richards, Allen L

    2016-04-01

    Rickettsia montanensis has long been considered a nonpathogenic member of the spotted fever group rickettsiae. However, the infection potential of R. montanensis is being revisited in light of its recent association with a case of human infection in the United States and the possibility that additional cases may have been misdiagnosed as Rocky Mountain spotted fever. To this end, DNA was extracted from American dog ticks (Dermacentor variabilis) removed from Department of Defense (DoD) personnel and their dependents at DoD medical treatment facilities (MTFs) during 2002-2012 (n = 4792). These 4792 samples were analyzed for the presence of R. montanensis (n =  36; 2.84%) and all vector DNA was confirmed to be of D. variabilis origin using a novel Dermacentor genus-specific quantitative real-time polymerase chain reaction procedure, Derm, and a novel Dermacentor species multilocus sequence typing assay. To assess the risk of R. montanensis infection, the positive and negative samples were geographically mapped utilizing MTF site locations. Tick localities were imported into a geographical information systems (GIS) program, ArcGIS, for mapping and analysis. The ecological niche modeling (ENM) program, Maxent, was used to estimate the probability of tick presence in eastern United States using locations of both R. montanensis-positive and -negative ticks, climate, and elevation data. The ENM for R. montanensis-positive D. variabilis estimated high probabilities of the positive ticks occurring in two main areas, including the northern Midwest and mid-Atlantic portions of the northeastern regions of United States, whereas the R. montanensis-negative D. variabilis tick model showed a wider estimated range. The results suggest that R. montanensis-positive and -negative D. variabilis have different ranges where humans may be at risk and are influenced by similar and different factors.

  11. Parallelization of Reversible Ripple-carry Adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock

    2009-01-01

    wherein $m$ parallel $k$-bit reversible ripple-carry adders are combined to form a reversible $mk$-bit \\emph{ripple-block carry adder} with logic depth $\\mathcal{O}(m+k)$ for a \\emph{minimal} logic depth $\\mathcal{O}(\\sqrt{mk})$, thus improving on the $mk$-bit ripple-carry adder logic depth $\\mathcal......{O}(m\\cdot k)$. The underlying mechanisms of the parallelization scheme are formally proven correct. We also show designs for garbage-less reversible comparison circuits. We compare the circuit costs of the resulting ripple-block carry adder with known optimized reversible ripple-carry adders in measures...... of circuit delay, width, gate, transistor count, and relative power efficiency, and find that the parallelized adder offers significant speedups at realistic word sizes with modest parallelization overhead....

  12. Sister Carrie, an Adherent of Desires

    Institute of Scientific and Technical Information of China (English)

    裴水妹

    2007-01-01

    Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.

  13. Gun Carrying by High School Students in Boston, MA: Does Overestimation of Peer Gun Carrying Matter?

    Science.gov (United States)

    Hemenway, David; Vriniotis, Mary; Johnson, Renee M.; Miller, Matthew; Azrael, Deborah

    2011-01-01

    This paper investigates: (1) whether high school students overestimate gun carrying by their peers, and (2) whether those students who overestimate peer gun carrying are more likely to carry firearms. Data come from a randomly sampled survey conducted in 2008 of over 1700 high school students in Boston, MA. Over 5% of students reported carrying a…

  14. Carry Select Adder Circuit with A Successively Incremented Carry Number Block

    OpenAIRE

    Deepak; Bal Krishan

    2014-01-01

    This paper reports a conditional carry select (CCS) adder circuit with a successively-incremented-carry-number block (SICNB) structure for low-voltage VLSI implementation. Owing to the successively-incremented-carry-number block (SICNB) structure, the new 16-bit SICNB CCS adder provides a 37% faster speed as compared to the conventional conditional Carry select adder based on the SPICE results

  15. Study of infection by Rickettsiae of the spotted fever group in humans and ticks in an urban park located in the City of Londrina, State of Paraná, Brazil Estudo da infecção por Rickettsias do grupo da febre maculosa em humanos e carrapatos de um parque urbano na Cidade de Londrina, Estado do Paraná

    Directory of Open Access Journals (Sweden)

    Roberta Santos Toledo

    2011-06-01

    Full Text Available INTRODUCTION: Spotted fevers are emerging zoonoses caused by Rickettsia species in the spotted fever group (SFG. Rickettsia rickettsii is the main etiologic agent of Brazilian spotted fever (BSF and it is transmitted by Amblyomma spp. ticks. METHODS: The study aimed to investigate SFG rickettsiae in the Arthur Thomas Municipal Park in Londrina, PR, by collecting free-living ticks and ticks from capybaras and blood samples from personnel working in these areas. Samples from A. dubitatum and A. cajennense were submitted for PCR in pools to analyze the Rickettsia spp. gltA (citrate synthase gene. RESULTS: All the pools analyzed were negative. Human sera were tested by indirect immunofluorescence assay with R. rickettsii and R. parkeri as antigens. Among the 34 sera analyzed, seven (20.6% were reactive for R. rickettsii: four of these had endpoint titers equal to 64, 2 titers were 128 and 1 titer was 256. None of the samples were reactive for R. parkeri. An epidemiological questionnaire was applied to the park staff, but no statistically significant associations were identified. CONCLUSIONS: The serological studies suggest the presence of Rickettsiae related to SFG that could be infecting the human population studied; however, analysis of the ticks collected was unable to determine which species may be involved in transmission to humans.INTRODUÇÃO: A febre maculosa é uma zoonose emergente causada por espécies de Rickettsia do grupo febre maculosa (GFM. Rickettsia rickettsii é o principal agente etiológico da febre maculosa brasileira (FMB e é transmitida por Amblyomma spp. MÉTODOS: Com o objetivo de obter informações sobre GFM Rickettsiae no Parque Municipal Arthur Thomas em Londrina, PR, carrapatos de vida livre e de capivaras foram coletados, assim como amostras de sangue das pessoas que trabalham no parque. A. dubitatum e A. cajennense foram submetidos à PCR em pools para analises de Rickettsia spp. gltA (citrate synthase gene

  16. Effects of carrying methods and box handles on two-person team carrying capacity for females.

    Science.gov (United States)

    Wu, Swei-Pi; Chang, Shu-Yu

    2010-07-01

    This study used a psychophysical approach to examine the effects of carrying methods and the presence or absence of box handles on the maximum acceptable weight carried and resulting responses (heart rate and rating of perceived exertion) in a two-person carrying task. After training, 16 female subjects performed a two-person carrying task at knuckle height for an 8-h work period. Each subject performed 4 different carrying combinations two times. The independent variables were carrying methods (parallel and tandem walking) and box handles (with and without handles). For comparison with two-person carrying, the subjects also performed one-person carrying. The results showed that the maximum acceptable weight carried (MAWC), heart rate (HR), and rating of perceived exertion (RPE) were significantly affected by the presence of box handles. However, the subjects' MAWC, HR, and RPE values were not significantly influenced by the carrying methods. The test-retest reliability of the psychophysical approach was 0.945. The carrying efficiency of two-person carrying was 96.2% of the one-person carrying method. In general, the use of box with handles allows the subjects to carry a higher MAWC (with lower HR and RPE) compared to carrying boxes without handles.

  17. A study of the presence of B. burgdorferi, Anaplasma (previously Ehrlichia) phagocytophilum, Rickettsia, and Babesia in Ixodes ricinus collected within the territory of Belluno, Italy.

    Science.gov (United States)

    Piccolin, G; Benedetti, G; Doglioni, C; Lorenzato, C; Mancuso, S; Papa, N; Pitton, L; Ramon, M C; Zasio, C; Bertiato, G

    2006-01-01

    In the years 2000 and 2001, we sampled ticks in order to establish the distribution of Ixodes ricinus in the province of Belluno; 5987 tick samples from 244 sites throughout the province were gathered, by dragging for a 5-min period. In 40 sites, seasonal variations and cycle stages of the parasites were studied at monthly intervals from March to September. A polymerase chain reaction (PCR) technique was used to identify the tick-infected sites. Of 1931 individual ticks, 8.23% were positive for Borrelia burgdorferi, 4.4% were positive for Ehrlichia, 1.6% were positive for Rickettsia, and 1.6% were positive for Babesia. The co-presence of Borrelia and Ehrlichia (1.2%) and Babesia (0.5%), Borrelia, Ehrlichia and Rickettsia (0.1%) was also found.

  18. Questing Amblyomma mixtum and Haemaphysalis juxtakochi (Acari: Ixodidae) Infected with Candidatus "Rickettsia amblyommii" from the Natural Environment in Panama Canal Basin, Panama.

    Science.gov (United States)

    D, Angélica M Castro; S, Gleidys G García; Dzul-Rosado, Karla; Aguilar, Ana; Castillo, Juan; Gabster, Amanda; Trejos, Diomedes; Zavala-Castro, Jorge; Bermúdez C, Sergio E

    2015-12-01

    This work emphasizes the detection of Candidatus "Rickettsia amblyommii" in questing Haemaphysalis juxtakochi and Amblyomma mixtum. From February 2009 to December 2012, questing ticks were collected from the vegetation and leaf-litter of four protected forests and two grassy areas around the Panama Canal basin. DNA was extracted from Amblyomma mixtum, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma pecarium, Amblyomma tapirellum, Haemaphysalis juxtakochi, and unidentified immature Amblyomma. Specific primers of citrate synthase gene gltA were used to detect and identify the rickettsiae. Amplicons with the expected band size were purified and sequenced. DNA of C. "R. amblyommii" was found in A. mixtum, H. juxtakochi and Amblyomma immatures. To our knowledge, these finding represent the first report of C. "R. amblyommii" in free-living ticks in the wilderness of Central America.

  19. Genetic identification of Rickettsia sp. strain Atlantic rainforest in an endemic area of a mild spotted fever in Rio Grande do Sul state, Southern Brazil.

    Science.gov (United States)

    Figueiredo Voizzoni, Vinicius; Barbosa Silva, Arannadia; Medeiros Cardoso, Karen; Barbosa Dos Santos, Fernanda; Stenzel, Barbara; Amorim, Marinete; Vilges de Oliveira, Stefan; Salles Gazeta, Gilberto

    2016-10-01

    Rickettsia sp. strain Atlantic rainforest causes a less severe rickettsiosis, with two cases confirmed until now. The tick species Amblyomma ovale is appointed as the main vector of this bacterium. The southern region of Brazil has reported patients with spotted fever who have milder symptoms. In 2013, during an investigation of rickettsiosis cases, an A. ovale tick was found attached to a man in an area where there were two cases. The parasite was processed for molecular analysis and the rickettsial infection was confirmed based on phylogenetic analysis of genes ompA, ompB and geneD (sca4). In the present study the human pathogenic Rickettsia sp. strain Atlantic rainforest was identified in the state of Rio Grande do Sul, Southern Brazil. Since A. ovale, its main vector, is found frequently parasitizing dogs, animals that can cross international borders freely in southern Brazil, this bacteria can bring major concerns in terms of public health.

  20. A Naturalistic Reading of Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    谈月

    2016-01-01

    Sister Carrie is well known as the works in which naturalism attained maturity in America. Up until now, the relevant research on Dreiser and his Sister Carrie abroad and at home is primarily concerned with the frustration of American dream, the naturalistic thoughts and pessimism. The paper attempts to study it from naturalistic point of view and explain how environmental, hereditary factors and the idea of“survival of the fittest”influence Carrie’s fate.

  1. Questing Amblyomma mixtum and Haemaphysalis juxtakochi (Acari: Ixodidae) Infected with Candidatus “Rickettsia amblyommii” from the Natural Environment in Panama Canal Basin, Panama

    OpenAIRE

    D., Angélica M. Castro; S., Gleidys G. García; Dzul-Rosado, Karla; Aguilar, Ana; Castillo,Juan; Gabster, Amanda; Trejos, Diomedes; Zavala-Castro, Jorge; Bermúdez C., Sergio E.

    2015-01-01

    This work emphasizes the detection of Candidatus “Rickettsia amblyommii” in questing Haemaphysalis juxtakochi and Amblyomma mixtum. From February 2009 to December 2012, questing ticks were collected from the vegetation and leaf-litter of four protected forests and two grassy areas around the Panama Canal basin. DNA was extracted from Amblyomma mixtum, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma pecarium, Amblyomma tapirellum, Haemaphysalis juxtakochi, and unidentified immature A...

  2. Effects of box handle position and carrying range on bi-manual carrying capacity for females.

    Science.gov (United States)

    Wu, Swei-Pi; Loiu, Yi; Chien, Te Hong

    2015-01-01

    This study utilizes a psychophysical approach to examine the effects on carrying capacity for bi-manual carrying tasks involving different handle positions and carrying ranges. A total of 16 female subjects participated in the experiment in groups of two people, and each group of subjects performed the tasks in a random order with 12 different combinations of carrying task. The independent variables are handle position (upper, middle, lower) and carrying range (F-F: floor height carried to floor height, F-W: floor height carried to waist height, W-W: waist height carried to waist height, W-F: waist height carried to floor height), the dependent variable is the maximum acceptable carried weight (MAWC), heart rate (HR), and the rating of perceived exertion (RPE). The results show that the handle position has a significant effect on MAWC and overall RPE but no significant effect on HR. Carrying range has a significant effect on the MAWC and HR, but no significant effect on overall HR. The handle position and carrying range have a significant interaction on the MAWC and HR. The RPE for different body parts shows significant differences, and the hands feel the most tired. Overall, this study confirms that the lower handle position with the W-W carrying range is the best combination for a two-person carrying task.

  3. Optimal growth trajectories with finite carrying capacity.

    Science.gov (United States)

    Caravelli, F; Sindoni, L; Caccioli, F; Ududec, C

    2016-08-01

    We consider the problem of finding optimal strategies that maximize the average growth rate of multiplicative stochastic processes. For a geometric Brownian motion, the problem is solved through the so-called Kelly criterion, according to which the optimal growth rate is achieved by investing a constant given fraction of resources at any step of the dynamics. We generalize these finding to the case of dynamical equations with finite carrying capacity, which can find applications in biology, mathematical ecology, and finance. We formulate the problem in terms of a stochastic process with multiplicative noise and a nonlinear drift term that is determined by the specific functional form of carrying capacity. We solve the stochastic equation for two classes of carrying capacity functions (power laws and logarithmic), and in both cases we compute the optimal trajectories of the control parameter. We further test the validity of our analytical results using numerical simulations.

  4. Optimal growth trajectories with finite carrying capacity

    Science.gov (United States)

    Caravelli, F.; Sindoni, L.; Caccioli, F.; Ududec, C.

    2016-08-01

    We consider the problem of finding optimal strategies that maximize the average growth rate of multiplicative stochastic processes. For a geometric Brownian motion, the problem is solved through the so-called Kelly criterion, according to which the optimal growth rate is achieved by investing a constant given fraction of resources at any step of the dynamics. We generalize these finding to the case of dynamical equations with finite carrying capacity, which can find applications in biology, mathematical ecology, and finance. We formulate the problem in terms of a stochastic process with multiplicative noise and a nonlinear drift term that is determined by the specific functional form of carrying capacity. We solve the stochastic equation for two classes of carrying capacity functions (power laws and logarithmic), and in both cases we compute the optimal trajectories of the control parameter. We further test the validity of our analytical results using numerical simulations.

  5. Carry Select Adder Circuit with A Successively Incremented Carry Number Block

    Directory of Open Access Journals (Sweden)

    Deepak

    2014-04-01

    Full Text Available This paper reports a conditional carry select (CCS adder circuit with a successively-incremented-carry-number block (SICNB structure for low-voltage VLSI implementation. Owing to the successively-incremented-carry-number block (SICNB structure, the new 16-bit SICNB CCS adder provides a 37% faster speed as compared to the conventional conditional Carry select adder based on the SPICE results

  6. A Feminist Reading of Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    Wang Jiatong

    2015-01-01

    In the history of American literature,Sister Carrie is the first novel of Theodore Dreiser,it impresses people deeply. Carrie,a poor country girl,becomes a famous star in a big city. She has totally changed from her hard experiences,and she becomes financially independent as a new woman when she goes through hesitation.In he whole novel,the author has planted some strong points of Carrie’s character.At the end of this paper,it analyzes woman’s status in modern time from two aspects of the improvement of female’s social status and the comparison between men and women.

  7. Rapid, simple, and sensitive detection of the ompB gene of spotted fever group rickettsiae by loop-mediated isothermal amplification

    Directory of Open Access Journals (Sweden)

    Pan Lei

    2012-10-01

    Full Text Available Abstract Background Spotted fever caused spotted fever group rickettsiae (SFGR is prevalent throughout China. In this study, we describe a rapid, simple, and sensitive loop-mediated isothermal amplification (LAMP assay targeting the ompB gene of spotted fever group rickettsiae ideal for application in China. The LAMP assay has the potential to detect spotted fever group rickettsiae early in infection and could therefore serve as an alternative to existing methods. Methods A set of universal primers which are specific 7 common species of spotted fever group rickettsiae in China were designed using PrimerExplorer V4 software based on conserved sequences of ompB gene. The sensitivity, specificity and reproducibility of the LAMP were evaluated. The LAMP assay for detecting SFGR was compared with conventional PCR assays for sensitivity and specificity in early phase blood samples obtained from 11 infected human subjects. Results The sensitivity of the LAMP assay was five copies per reaction (25 μL total volume, and the assay did not detect false-positive amplification across 42 strains of 27 members of the order Rickettsiales and 17 common clinical pathogens. The LAMP assay was negative to typhus group rickettsiae including R. prowazekii and R. typhi for no available conserved sequences of ompB was obtained for designing primers. To evaluate the clinical applicability of the LAMP assay, a total of 11 clinical samples, 10 samples confirmed serologically (3 cases, ecologically (1 case, by real-time polymerase chain reaction (PCR; 2 cases, ecologically and by real-time PCR (1 case, and serologically and by real-time PCR (3 cases were analyzed by the ompB LAMP assay. Data were validated using a previously established nested PCR protocol and real-time PCR. A positive LAMP result was obtained for 8 of the 10 confirmed cases (sensitivity, 73%; specificity, 100%, while none of these samples were positive by nested PCR (sensitivity, 0%; specificity, 100

  8. Error propagation in energetic carrying capacity models

    Science.gov (United States)

    Pearse, Aaron T.; Stafford, Joshua D.

    2014-01-01

    Conservation objectives derived from carrying capacity models have been used to inform management of landscapes for wildlife populations. Energetic carrying capacity models are particularly useful in conservation planning for wildlife; these models use estimates of food abundance and energetic requirements of wildlife to target conservation actions. We provide a general method for incorporating a foraging threshold (i.e., density of food at which foraging becomes unprofitable) when estimating food availability with energetic carrying capacity models. We use a hypothetical example to describe how past methods for adjustment of foraging thresholds biased results of energetic carrying capacity models in certain instances. Adjusting foraging thresholds at the patch level of the species of interest provides results consistent with ecological foraging theory. Presentation of two case studies suggest variation in bias which, in certain instances, created large errors in conservation objectives and may have led to inefficient allocation of limited resources. Our results also illustrate how small errors or biases in application of input parameters, when extrapolated to large spatial extents, propagate errors in conservation planning and can have negative implications for target populations.

  9. Increased carrying capacity with perennial forage kochia

    Science.gov (United States)

    Carrying capacity can be increased on grass-dominated rangeland pastures by including perennial forage kochia (Kochia prostrata) as one of the plant components. The objectives of the study reported here were to compare the differences of traditional winter pastures versus pastures with forage kochi...

  10. Occurrence of Babesia spp., Rickettsia spp. and Bartonella spp. in Ixodes ricinus in Bavarian public parks, Germany

    Directory of Open Access Journals (Sweden)

    Mahling Monia

    2011-07-01

    Full Text Available Abstract Background Only limited information is available about the occurrence of ticks and tick-borne pathogens in public parks, which are areas strongly influenced by human beings. For this reason, Ixodes ricinus were collected in public parks of different Bavarian cities in a 2-year survey (2009 and 2010 and screened for DNA of Babesia spp., Rickettsia spp. and Bartonella spp. by PCR. Species identification was performed by sequence analysis and alignment with existing sequences in GenBank. Additionally, coinfections with Anaplasma phagocytophilum were investigated. Results The following prevalences were detected: Babesia spp.: 0.4% (n = 17, including one pool of two larvae in 2009 and 0.5 to 0.7% (n = 11, including one pool of five larvae in 2010; Rickettsia spp.: 6.4 to 7.7% (n = 285, including 16 pools of 76 larvae in 2009. DNA of Bartonella spp. in I. ricinus in Bavarian public parks could not be identified. Sequence analysis revealed the following species: Babesia sp. EU1 (n = 25, B. divergens (n = 1, B. divergens/capreoli (n = 1, B. gibsoni-like (n = 1, R. helvetica (n = 272, R. monacensis IrR/Munich (n = 12 and unspecified R. monacensis (n = 1. The majority of coinfections were R. helvetica with A. phagocytophilum (n = 27, but coinfections between Babesia spp. and A. phagocytophilum, or Babesia spp. and R. helvetica were also detected. Conclusions I. ricinus ticks in urban areas of Germany harbor several tick-borne pathogens and coinfections were also observed. Public parks are of particularly great interest regarding the epidemiology of tick-borne pathogens, because of differences in both the prevalence of pathogens in ticks as well as a varying species arrangement when compared to woodland areas. The record of DNA of a Babesia gibsoni-like pathogen detected in I. ricinus suggests that I. ricinus may harbor and transmit more Babesia spp. than previously known. Because of their high recreational value for human beings, urban green

  11. Like an eagle carries its young

    Directory of Open Access Journals (Sweden)

    Hans-Georg Wünch

    2016-04-01

    Full Text Available The picture of an eagle carrying its young on its wings (Dt 32:11 is a powerful and encouraging image of trust and security in God. It is particularly relevant for Western culture, where the eagle is a prominent symbol of power and strength. In recent years, though, the translation of the Hebrew term רֶשֶׁנ as ‘eagle’ has come into question and modern exegetes claim that it is more accurately translated as ‘vulture’. But can this really be a symbol of comfort? Furthermore, do eagles (or vultures even carry their young on their wings? This article intends to shed some light on these questions.Keywords: Old Testament; Deuteronomy; Eagle; Vulture

  12. A decimal carry-free adder

    Science.gov (United States)

    Nikmehr, Hooman; Phillips, Braden; Lim, Cheng-Chew

    2005-02-01

    Recently, decimal arithmetic has become attractive in the financial and commercial world including banking, tax calculation, currency conversion, insurance and accounting. Although computers are still carrying out decimal calculation using software libraries and binary floating-point numbers, it is likely that in the near future, all processors will be equipped with units performing decimal operations directly on decimal operands. One critical building block for some complex decimal operations is the decimal carry-free adder. This paper discusses the mathematical framework of the addition, introduces a new signed-digit format for representing decimal numbers and presents an efficient architectural implementation. Delay estimation analysis shows that the adder offers improved performance over earlier designs.

  13. Computer Simulation Instruction: Carrying out Chemical Experiments

    Directory of Open Access Journals (Sweden)

    Ibtesam Al-Mashaqbeh

    2014-05-01

    Full Text Available The purpose of this study was to investigate the effect of computer simulation Instruction (CSI on students' achievements: Carrying out chemical experiments to acquire chemical concepts for eleventh grade students. The subject of the study consisted two sections of a one girl's high school in Jordan. One section was randomly assigned to experimental group in which computer simulation Instruction (CSI was used, and the other section was randomly assigned to control group in which students were instructed by using the traditional teaching instruction. The findings indicated that there is progress on the part of the experimental group which used the computer simulation Instruction (CSI and this was reflected positively in the students’ achievement in carrying out chemical experiments to acquire chemical concepts.

  14. Proof-Carrying Code with Correct Compilers

    Science.gov (United States)

    Appel, Andrew W.

    2009-01-01

    In the late 1990s, proof-carrying code was able to produce machine-checkable safety proofs for machine-language programs even though (1) it was impractical to prove correctness properties of source programs and (2) it was impractical to prove correctness of compilers. But now it is practical to prove some correctness properties of source programs, and it is practical to prove correctness of optimizing compilers. We can produce more expressive proof-carrying code, that can guarantee correctness properties for machine code and not just safety. We will construct program logics for source languages, prove them sound w.r.t. the operational semantics of the input language for a proved-correct compiler, and then use these logics as a basis for proving the soundness of static analyses.

  15. A Feminist Reading of Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    Wang; Jiatong

    2015-01-01

    In the history of American literature,Sister Carrie is the first novel of Theodore Dreiser,it impresses people deeply.Carrie,a poor country girl,becomes a famous star in a big city.She has totally changed from her hard experiences,and she becomes financially independent as a new woman when she goes through hesitation.In he whole novel,the author has planted some strong points of Carrie’s character.At the end of this paper,it analyzes woman’s status in modern time from two aspects of the improvement of female’s social status and the comparison between men and women.

  16. 'Candidatus Megaira polyxenophila' gen. nov., sp. nov.: considerations on evolutionary history, host range and shift of early divergent rickettsiae.

    Directory of Open Access Journals (Sweden)

    Martina Schrallhammer

    Full Text Available "Neglected Rickettsiaceae" (i.e. those harboured by non-hematophagous eukaryotic hosts display greater phylogenetic variability and more widespread dispersal than pathogenic ones; yet, the knowledge about their actual host range and host shift mechanism is scarce. The present work reports the characterization following the full-cycle rRNA approach (SSU rRNA sequence, specific in situ hybridization, and ultrastructure of a novel rickettsial bacterium, herewith proposed as 'Candidatus Megaira polyxenophila' gen. nov., sp. nov. We found it in association with four different free-living ciliates (Diophrys oligothrix, Euplotes octocarinatus, Paramecium caudatum, and Spirostomum sp., all belonging to Alveolata, Ciliophora; furthermore it was recently observed as intracellular occurring in Carteria cerasiformis and Pleodorina japonica (Chlorophyceae, Chlorophyta. Phylogenetic analyses demonstrated the belonging of the candidate new genus to the family Rickettsiaceae (Alphaproteobacteria, Rickettsiales as a sister group of the genus Rickettsia. In situ observations revealed the ability of the candidate new species to colonize either nuclear or cytoplasmic compartments, depending on the host organism. The presence of the same bacterial species within different, evolutionary distant, hosts indicates that 'Candidatus Megaira polyxenophila' recently underwent several distinct host shifts, thus suggesting the existence of horizontal transmission pathways. We consider these findings as indicative of an unexpected spread of rickettsial infections in aquatic communities, possibly by means of trophic interactions, and hence propose a new interpretation of the origin and phylogenetic diversification of rickettsial bacteria.

  17. The Rickettsia prowazekii invasion gene homolog (invA) encodes a Nudix hydrolase active on adenosine (5')-pentaphospho-(5')-adenosine.

    Science.gov (United States)

    Gaywee, Jariyanart; Xu, WenLian; Radulovic, Suzana; Bessman, Maurice J; Azad, Abdu F

    2002-03-01

    The genomic sequence of Rickettsia prowazekii, the obligate intracellular bacterium responsible for epidemic typhus, reveals an uncharacterized invasion gene homolog (invA). The deduced protein of 18,752 Da contains a Nudix signature, the specific motif found in the Nudix hydrolase family. To characterize the function of InvA, the gene was cloned and overexpressed in Escherichia coli. The expressed protein was purified to near homogeneity and subsequently tested for its enzymatic activity against a series of nucleoside diphosphate derivatives. The purified InvA exhibits hydrolytic activity toward dinucleoside oligophosphates (Np(n)N; n > or = 5), a group of cellular signaling molecules. At optimal pH 8.5, the enzyme actively degrades adenosine (5')-pentaphospho-(5')-adenosine into ATP and ADP with a K(m) of 0.1 mM and k(cat) of 1.9 s(-1). Guanosine (5')-pentaphospho-(5')-guanosine and adenosine-(5')-hexaphospho (5')-adenosine are also substrates. Similar to other Nudix hydrolases, InvA requires a divalent metal cation, Mg(2+) or Zn(2+), for optimal activity. These data suggest that the rickettsial invasion protein likely plays a role in controlling the concentration of stress-induced dinucleoside oligophosphates following bacterial invasion.

  18. Information carrying capacity of a cosmological constant

    Science.gov (United States)

    Simidzija, Petar; Martín-Martínez, Eduardo

    2017-01-01

    We analyze the exchange of information in different cosmological backgrounds when sender and receiver are timelike separated and communicate through massless fields (without the exchange of light signals). Remarkably, we show that the dominance of a cosmological constant makes the amount of recoverable information imprinted in the field by the sender extremely resilient: it does not decay in time or with the spatial separation of the sender and receiver, and it actually increases with the rate of expansion of the Universe. This is in stark contrast with the information carried by conventional light signals and with previous results on timelike communication through massless fields in matter-dominated cosmologies.

  19. Aislamiento, caracterización genética y análisis filogenético de Rickettsia massiliae, Ciudad Autónoma de Buenos Aires

    OpenAIRE

    Gabriel L Cicuttin

    2016-01-01

    Rickettsia massiliae es un miembro del grupo de la fiebre manchada del género Rickettsia que fue aislado por primera vez en una garrapata Rhipicephalus turanicus de Francia. En el nuevo mundo, se detectó en garrapatas Rhipicephalus sanguineus de diferentes lugares de Argentina y EE.UU., pero sólo fue aislada en Arizona. El objetivo de este estudio fue el aislamiento y la caracterización genética de R. massiliae desde garrapatas R. sanguineus colectadas en perros de la Ciudad Autónoma de Bueno...

  20. Detection and identification of Rickettsia and rickettsial diseases%立克次体与立克次体病的检测与鉴定

    Institute of Scientific and Technical Information of China (English)

    张骁鹏; 李炘檑; 郑波; 胡晓梅

    2015-01-01

    立克次体是一类严格细胞内寄生的原核细胞型微生物,已被列入生物战剂名录。立克次体病是一类严重威胁人类健康的人兽共患的自然疫源性疾病。立克次体严格的细胞寄生性决定了立克次体病的诊断不同于传统方法,需根据流行病学资料、临床症状和体征及实验室检测进行综合判断,通常实验室检测是明确诊断的主要依据。从病原体的分离和培养到目前的基因水平比对,立克次体的检测技术虽发展了100多年,但人类尚未实现早期快速诊断立克次体病的目标。本文主要综述了立克次体与立克次体病检测与鉴定的研究进展。%Rickettsia is an obligate intracellular parasitic bacterium which has been included in the list of biowarfare agents .Rickettsial diseases are zoonotic ,natural focal diseases ,and also threats to human health seriously .Different from the standard detection methods for other bacteria , the diagnosis of rickettsial diseases needs a collective consideration of the epidemiological data ,clinical symptoms and laboratory test results .Although Rickettsia detection technology has been developed for more than 100 years ,early rapid diagnosis is still difficult . Current progresses on Rickettsia and rickettsial disease detection , including pathogen isolation and molecular detections ,are reviewed in this paper .

  1. Presence of Bartonella species and Rickettsia species DNA in the blood, oral cavity, skin and claw beds of cats in the United States.

    Science.gov (United States)

    Lappin, Michael R; Hawley, Jennifer

    2009-10-01

    The purpose of this study was to determine the prevalence of Bartonella species and Rickettsia species DNA in the blood, oral cavity, skin and claw beds of feral cats without evidence of skin disease that were housed in Alabama (n = 24), Florida (n = 27) and Colorado (n = 32). Samples were assessed by use of polymerase chain reaction assays. The Bartonella species IgG prevalence was also determined. While Bartonella species DNA was not amplified from any sample from Colorado cats, it was commonly amplified from blood (56.9%), skin (31.4%), claws (17.6%) and gingiva (17.6%) of the 51 cats housed in Alabama and Florida. All 10 flea groups assessed in this study were infected with a Bartonella species or R. felis. Bartonella species IgG titres did not accurately predict bacteraemia (positive predictive value = 57.1%; negative predictive value = 82.1%). Bartonella species DNA was amplified from blood of cats with and without C. felis. Rickettsia felis DNA was only detected in or on the skin of one cat and the gingiva of an additional cat. It was concluded that cats can be an occupational health risk for veterinarians, particularly in areas with high prevalence of Ctenocephalides felis. Further study is required to determine whether Bartonella species or Rickettsia species infections of cats are associated with dermatological disease. The combination of Bartonella species serological test results with Bartonella species PCR or culture is likely to give the most accurate information concerning the current infection status of individual cats.

  2. Exposure and risk factors to coxiella burnetii, spotted fever group and typhus group Rickettsiae, and Bartonella henselae among volunteer blood donors in Namibia.

    Directory of Open Access Journals (Sweden)

    Bruce H Noden

    Full Text Available The role of pathogen-mediated febrile illness in sub-Saharan Africa is receiving more attention, especially in Southern Africa where four countries (including Namibia are actively working to eliminate malaria. With a high concentration of livestock and high rates of companion animal ownership, the influence of zoonotic bacterial diseases as causes of febrile illness in Namibia remains unknown.The aim of the study was to evaluate exposure to Coxiella burnetii, spotted fever and typhus group rickettsiae, and Bartonella henselae using IFA and ELISA (IgG in serum collected from 319 volunteer blood donors identified by the Blood Transfusion Service of Namibia (NAMBTS. Serum samples were linked to a basic questionnaire to identify possible risk factors. The majority of the participants (64.8% had extensive exposure to rural areas or farms. Results indicated a C. burnetii prevalence of 26.1% (screening titre 1∶16, and prevalence rates of 11.9% and 14.9% (screening titre 1∶100 for spotted fever group and typhus group rickettsiae, respectively. There was a significant spatial association between C. burnetii exposure and place of residence in southern Namibia (P0.012, especially cattle (P>0.006, were also significantly associated with C. burnetii exposure. Males were significantly more likely than females to have been exposed to spotted fever (P<0.013 and typhus (P<0.011 group rickettsiae. Three (2.9% samples were positive for B. henselae possibly indicating low levels of exposure to a pathogen never reported in Namibia.These results indicate that Namibians are exposed to pathogenic fever-causing bacteria, most of which have flea or tick vectors/reservoirs. The epidemiology of febrile illnesses in Namibia needs further evaluation in order to develop comprehensive local diagnostic and treatment algorithms.

  3. Estudo biomolecular de Rickettsia rickettsii (Ricketts, 1909) em Amblyomma cajennense (Fabricius, 1787) e Amblyomma dubitatum (Neumann, 1899) (Acari: ixodidae) em Coronel Pacheco, Minas Gerais. 2004.

    OpenAIRE

    Elizangela Guedes

    2005-01-01

    Devido ao potencial papel atribuído a Amblyomma cajennense e a Amblyomma dubitatum no ciclo enzoótico de Rickettsia rickettsii, o agente etiológico da Febre Maculosa Brasileira (FMB), espécies de carrapatos, bem como a freqüência de infecção de carrapatos por R. rickettsii numa área focal de FMB em Minas Gerais. Um total de 78 exemplares de A. cajennense e 78 de A. dubitatum forma coletados e, posteriormente, submetidos ao teste de hemolinfa com resultado negativo para todas as amostras anali...

  4. DESIGN OF OPTIMAL CARRY SKIP ADDER AND CARRY SKIP BCD ADDER USING REVERSIBLE LOGIC GATES

    OpenAIRE

    Praveena Murugesan; Thanushkodi Keppanagounder

    2014-01-01

    Reversible logic circuits have the ability to produce zero power dissipation which has found its importance in quantum computing, optical computing and low power digital circuits. The study presents improved and efficient reversible logic circuits for carry skip adder and carry skip BCD adder. The performance of the proposed architecture is better than the existing works in terms of gate count, garbage outputs and constant inputs. This design forms the basis for different quantum ALU and embe...

  5. Rickettsia rickettsii outer membrane protein YbgF induces protective immunity in C3H/HeN mice.

    Science.gov (United States)

    Gong, Wenping; Qi, Yong; Xiong, Xiaolu; Jiao, Jun; Duan, Changsong; Wen, Bohai

    2015-01-01

    Rickettsia rickettsii is the etiological agent of Rocky Mountain spotted fever (RMSF). YbgF and TolC are outer membrane-associated proteins of R. rickettsii that play important roles in its interaction with host cells. We investigated the immunogenicity of YbgF and TolC for protection against RMSF. We immunized C3H/HeN mice with recombinant R. rickettsii YbgF (rYbgF) or TolC (rTolC). Rickettsial burden and impairment in the lungs, spleens, and livers of rYbgF-immunized mice were significantly lower than in rTolC-immunized mice. The ratio of IgG2a to IgG1 in rYbgF-immunized mice continued to increase over the course of our experiments, while that in rTolC-immunized mice was reduced. The proliferation and cytokine secretion of CD4(+) and CD8(+) T cells isolated from R. rickettsii-infected mice were analyzed following antigen stimulation. The results indicated that proliferation and interferon (IFN)-γ secretion of CD4(+) or CD8(+) T cells in R. rickettsii-infected mice were significantly greater than in uninfected mice after stimulation with rYbgF. YbgF is a novel protective antigen of R. rickettsii. Protection conferred by YbgF is dependent upon IFN-γ-producing CD4(+) and CD8(+) T cells and IgG2a, which act in synergy to control R. rickettsii infection.

  6. Assessment of Domestic Goats as Models for Experimental and Natural Infection with the North American Isolate of Rickettsia slovaca

    Science.gov (United States)

    Keating, M. Kelly; Spivey, Pamela; Lathrop, George W.; Powell, Nathaniel; Levin, Michael L.

    2016-01-01

    Rickettsia slovaca is a tick-borne human pathogen that is associated with scalp eschars and neck lymphadenopathy known as tick-borne lymphadenopathy (TIBOLA) or Dermacentor-borne necrosis erythema and lymphadenopathy (DEBONEL). Originally, R. slovaca was described in Eastern Europe, but since recognition of its pathogenicity, human cases have been reported throughout Europe. European vertebrate reservoirs of R. slovaca remain unknown, but feral swine and domestic goats have been found infected or seropositive for this pathogen. Recently, a rickettsial pathogen identical to R. slovaca was identified in, and isolated from, the American dog tick, Dermacentor variabilis. In previous experimental studies, this organism was found infectious to guinea pigs and transovarially transmissible in ticks. In this study, domestic goats (Capra hircus) were experimentally inoculated with the North American isolate of this R. slovaca-like agent to assess their reservoir competence–the ability to acquire the pathogens and maintain transmission between infected and uninfected ticks. Goats were susceptible to infection as demonstrated by detection of the pathogen in skin biopsies and multiple internal tissues, but the only clinical sign of illness was transient fever noted in three out of four goats, and reactive lymphoid hyperplasia. On average, less than 5% of uninfected ticks acquired the pathogen while feeding upon infected goats. Although domestic goats are susceptible to the newly described North American isolate of R. slovaca, they are likely to play a minor role in the natural transmission cycle of this pathogen. Our results suggest that goats do not propagate the North American isolate of R. slovaca in peridomestic environments and clinical diagnosis of infection could be difficult due to the brevity and mildness of clinical signs. Further research is needed to elucidate the natural transmission cycle of R. slovaca both in Europe and North America, as well as to identify a

  7. MOLECULAR DETECTION AND CLONING FOR RICKETTSIA-LIKE BACTERIA OF MILKY HAEMOLYMPH DISEASE OF SPINY LOBSTER Panulirus spp.

    Directory of Open Access Journals (Sweden)

    Isti Koesharyani

    2017-01-01

    Full Text Available Spiny lobster (Panulirus homarus and Panulirus ornatus are important commodities for Indonesia. The aquaculture of lobster is susceptible for several diseases like parasite, fungi, bacteria, and virus. Among those diseases, milky haemolymph disease (MHD is often seen as a symptom to mass mortality occurred at lobster farms in Gerupuk Bay of Lombok. The purpose of this study was to determine the lobster diseases on cage culture in Gerupuk Bay of Lombok, West Nusa Tenggara. The study was undertaken from January to March 2015. Diseases status was determined by application of molecular plat-form, polymerase chain reaction (PCR with designation of specific primer for MHD (254F/R, 254F: 5’-CGA-GGA-CCA-GAG-ATG-GAC-CTT-3’ and 254R: 5’-GCT-CAT-TGT-CAC-CGC-CAT-TGT-3’ with PCR size product of 254 bp. and for cloned the pathogen was used TA-cloning Invitrogen for the DNA plasmid as positive control for other analysis. Several tissue samples i.e hepatopancreas, haemolymph, part of muscle hepatopancreas P. homarus and P. ornatus were taken from cage culture farms at Gerupuk Bay then preserved on 90% ethanol for further analysis by PCR and then the amplificated DNA were cloned into pCR®2.1 plasmid and transformed into competent E. coli. The result showed that almost all lobster samples from Gerupuk Bay were positive infected by MHD, as the results of PCR amplification whereas the band appeared at 254bp. Also MHD plasmid has been successfully cloned and will be used for further examination. Histopathologically in hepatopancreas infection have seen necrosis that contain numerous of rickettsia-like bacteria.

  8. Testability Synthesis for Jumping Carry Adders

    Directory of Open Access Journals (Sweden)

    Chien-In Henry Chen

    2002-01-01

    Full Text Available Synthesis for testability ensures that the synthesized circuit is testable by exploring the fundamental relationship between don't care and redundancy. With the exploration of the relationship, redundancy removal can be applied to improve the testability, reduce the area and improve the speed of a synthesized circuit. The test generation problems have been adequately solved, therefore an innovative testability synthesis strategy is necessary for achieving the maximum fault coverage and area reduction for maximum speed. This paper presents a testability synthesis methodology applicable to a top–down design method based on the identification and removal of redundant faults. Emphasis has been placed on the testability synthesis of a high-speed binary jumping carry adder. A synthesized 32-bit testable adder implemented by a 1.2 μm CMOS technology performs addition in 4.09 ns. Comparing with the original synthesized circuit, redundancy removal yields a 100% testable design with a 15% improvement in speed and a 25% reduction in area.

  9. Robust ferromagnetism carried by antiferromagnetic domain walls

    Science.gov (United States)

    Hirose, Hishiro T.; Yamaura, Jun-Ichi; Hiroi, Zenji

    2017-02-01

    Ferroic materials, such as ferromagnetic or ferroelectric materials, have been utilized as recording media for memory devices. A recent trend for downsizing, however, requires an alternative, because ferroic orders tend to become unstable for miniaturization. The domain wall nanoelectronics is a new developing direction for next-generation devices, in which atomic domain walls, rather than conventional, large domains themselves, are the active elements. Here we show that atomically thin magnetic domain walls generated in the antiferromagnetic insulator Cd2Os2O7 carry unusual ferromagnetic moments perpendicular to the wall as well as electron conductivity: the ferromagnetic moments are easily polarized even by a tiny field of 1 mT at high temperature, while, once cooled down, they are surprisingly robust even in an inverse magnetic field of 7 T. Thus, the magnetic domain walls could serve as a new-type of microscopic, switchable and electrically readable magnetic medium which is potentially important for future applications in the domain wall nanoelectronics.

  10. Retinal oscillations carry visual information to cortex

    Directory of Open Access Journals (Sweden)

    Kilian Koepsell

    2009-04-01

    Full Text Available Thalamic relay cells fire action potentials that transmit information from retina to cortex. The amount of information that spike trains encode is usually estimated from the precision of spike timing with respect to the stimulus. Sensory input, however, is only one factor that influences neural activity. For example, intrinsic dynamics, such as oscillations of networks of neurons, also modulate firing pattern. Here, we asked if retinal oscillations might help to convey information to neurons downstream. Specifically, we made whole-cell recordings from relay cells to reveal retinal inputs (EPSPs and thalamic outputs (spikes and then analyzed these events with information theory. Our results show that thalamic spike trains operate as two multiplexed channels. One channel, which occupies a low frequency band (<30 Hz, is encoded by average firing rate with respect to the stimulus and carries information about local changes in the visual field over time. The other operates in the gamma frequency band (40-80 Hz and is encoded by spike timing relative to retinal oscillations. At times, the second channel conveyed even more information than the first. Because retinal oscillations involve extensive networks of ganglion cells, it is likely that the second channel transmits information about global features of the visual scene.

  11. Efficient carry skip Adder design using full adder and carry skip block based on reversible Logic

    Directory of Open Access Journals (Sweden)

    Varun Pratap Singh

    2015-12-01

    Full Text Available In recent years, Reversible Logic is becoming more and more prominent technology having its applications in Quantum Computing, Nanotechnology, and Optical Computing. Reversibility plays an important role when energy efficient computations are considered. In this paper, binary full Adder with Design I and Design II are proposed. The performance analysis is verified using number of reversible gates, Garbage input/outputs, delay, number of logical calculations and Quantum Cost. According to the suitability of full adder design I and design II carry skip adder block is also constructed with some improvement in terms of delay in block carry generation. It is observed that Reversible carry skip Binary Adder with Design II is efficient compared to Design I

  12. Rickettsiae of spotted fever group, Borrelia valaisiana, and Coxiella burnetii in ticks on passerine birds and mammals from the Camargue in the south of France.

    Science.gov (United States)

    Socolovschi, Cristina; Reynaud, Pierre; Kernif, Tahar; Raoult, Didier; Parola, Philippe

    2012-12-01

    Ticks are obligate hematophagous arthropods that have a limited mobility, but can be transported over large geographical distances by wild and domestic mammals and birds. In this study, we analyze the presence of emerging zoonotic bacteria in ticks collected from passerine birds and mammals present in the Camargue, in the south of France, which is a major rallying point for birds migrating from Eurasia and Africa. The presence of Coxiella burnetii, Rickettsia, Borrelia, and Bartonella was examined by real-time PCR on DNA samples extracted from 118 ticks. Rickettsia massiliae was detected in ticks from Passer domesticus, Ri. aeschlimannii in ticks from Acrocephalus scirpaceus and Luscinia megarhynchos, and Borrelia valaisiana in one tick from Turdus merula. In addition, Ri. massiliae, Ri. slovaca, Candidatus Ri. barbariae, and C. burnetii were detected in ticks from dogs, horses, cats, and humans. No Bartonella DNA was detected in these samples. The migratory birds may play a role in the transmission of infectious diseases and contribute to the geographic distribution of Ri. aeschlimannii, Bo. valaisiana, and C. burnetii. The role of birds in spreading Rh. sanguineus ticks infected with Ri. massiliae needs to be clarified by complementary studies. This is the first detection of Candidatus Ri. barbariae in Rh. sanguineus from the south of France.

  13. Enhanced Expression of T-Cell Immunoglobulin and Mucin Domain Protein 3 in Endothelial Cells Facilitates Intracellular Killing of Rickettsia heilongjiangensis.

    Science.gov (United States)

    Yang, Xiaomei; Jiao, Jun; Han, Gencheng; Gong, Wenping; Wang, Pengcheng; Xiong, Xiaolu; Wen, Bohai

    2016-01-01

    Rickettsia heilongjiangensis is the pathogen of Far eastern spotted fever, and T-cell immunoglobulin and mucin domain protein 3 (Tim-3) is expressed in human vascular endothelial cells, the major target cells of rickettsiae. In the present study, we investigated the effects of altered Tim-3 expression in vivo in mice and in vitro in human endothelial cells, on day 3 after R. heilongjiangensis infection. Compared with corresponding controls, rickettsial burdens both in vivo and in vitro were significantly higher with blocked Tim-3 signaling or silenced Tim-3 and significantly lower with overexpressed Tim-3. Additionally, the expression of inducible nitric oxide synthase and interferon γ in endothelial cells with blocked Tim-3 signaling or silenced Tim-3 was significantly lower, while the expression of inducible nitric oxide synthase, interferon γ, and tumor necrosis factor α in transgenic mice with Tim-3 overexpression was significantly higher. These results reveal that enhanced Tim-3 expression facilitates intracellular rickettsial killing in a nitric oxide-dependent manner in endothelial cells during the early phase of rickettsial infection.

  14. Identification of Ctenocephalides felis fleas as a host of Rickettsia felis, the agent of a spotted fever rickettsiosis in Yucatań, Mexico.

    Science.gov (United States)

    Zavala-Velázquez, J E; Zavala-Castro, J E; Vado-Solís, I; Ruiz-Sosa, J A; Moron, C G; Bouyer, D H; Walker, D H

    2002-01-01

    In search for the vector of the recently recognized spotted fever rickettsiosis of the Yucatán, ticks, fleas, and lice were collected from vegetation and dogs in localities where seropositive persons had been found. The arthropods were examined by polymerase chain reaction (PCR) using primers for the genus-specific 17-kDa protein gene followed by restriction fragment length polymorphism (RFLP) and DNA sequencing. Eleven (20%) of 54 pools of Ctenocephalides felis fleas contained DNA of Rickettsia felis. None of 219 Amblyomma cajennense, 474 Rhiphicephalus sanguineus, 258 Boophilus sp. ticks, and 33 Poliplax species lice contained DNA of Rickettsia. The identity of the rickettsial DNA was confirmed as R. felis by PCR/RFLP for the citrate synthase and outer membrane protein A genes and by DNA sequencing. The results indicate that the host of R. felis in Yucatán is C. felis and suggest that the spotted fever rickettsiosis that has infected >5% of the population of the Yucatán and can present as a dengue-like illness is likely to be caused by R. felis.

  15. Evidencia serológica de la presencia de Rickettsias del grupo de la fiebre manchada en la Amazonía del Perú

    Directory of Open Access Journals (Sweden)

    Moisés Sihuincha M

    2006-10-01

    Full Text Available Con el objetivo de demostrar la existencia de transmisión de Rickettsias del grupo de la fiebre manchada en la Amazonía peruana, se tomaron muestras de sangre a pacientes febriles agudos en establecimientos de salud de la ciudad de Iquitos, la ciudad más poblada de la Amazonía del Perú. Las muestras fueron procesadas mediante inmunofluorescencia indirecta para medir anticuerpos totales e IgG específica para el grupo de fiebre de las manchadas. Entre enero y julio de 2006, se obtuvieron muestras de 250 pacientes. El 37% de las muestras tuvieron títulos positivos de IgG, demostrando así haber tenido contacto con el agente, de ellas, nueve fueron clasificadas como casos agudos, en los que se descartó otras infecciones endémicas como dengue, malaria y leptospirosis. Los casos presentaron una enfermedad febril acompañada de síntomas como tos, sarpullido y hemoptisis. Cuatro casos fueron hospitalizados, dos fueron graves y uno de ellos falleció. En conclusión, existe evidencia serológica de la circulación de Rickettsias del grupo de las fiebre manchada en la Amazonía peruana, por su frecuencia y potencial gravedad debería ser tomada en cuenta como diagnóstico diferencial del síndrome febril agudo en esta región.

  16. First identification of natural infection of Rickettsia rickettsii in the Rhipicephalus sanguineus tick, in the State of Rio de Janeiro Primeira identificação de infecção natural por Rickettsia rickettsii no carrapato Rhipicephalus sanguineus no Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Nathalie C. Cunha

    2009-02-01

    Full Text Available The Brazilian Spotted Fever (BSF is a zoonotic disease caused by Rickettsia rickettsii and transmitted by ticks of the genus Amblyomma, more frequently, Amblyomma cajennense. The aim of this paper was to report the first molecular detection of R. rickettsii on R. sanguineus naturally infected in Rio de Janeiro, Brazil. Ticks were collected from dogs in a rural region of Resende municipality, Rio de Janeiro State, Brazil (22º30'9.46"S, 44º42'44.29"WO, where occurred five human cases of BSF in 2006. The ticks were identified under a stereoscopic microscope and separated in pools by stages, species and sex. DNA extraction was carried out using QIAamp DNA Mini Kit (QIAGEN®. The DNA was submitted to PCR amplification using 04 set of primers: Rr190.70p/Rr190.602n (OmpA, 532bp, BG1-21/BG2-20 (OmpB, 650bp, Tz15/Tz16 (17 kDa protein-encoding gene, 246bp and RpCS.877p/RpCS.1258n (gltA, 381bp. PCR products were separated by electrophoresis on 1% agarose gels and visualized under ultraviolet light with ethidium bromide. PCR products of the expected sizes were purified by QIAquick® and sequenced by ABI PRISM®. The generated nucleotide sequences were edited with using Bioedit® software and compared with the corresponding homologous sequences available through GenBank, using Discontiguous Mega Blast (http://www.ncbi.nlm.nih.gov. It was confirmed R. rickettsii by sequencing of the material (GenBank FJ356230. The molecular characterization of R. rickettsii in the tick R. sanguineus emphasizes the role of dogs as carriers of ticks from the environment to home. Moreover, this result suggests that there is a considerable chance for active participation of R. sanguineus as one of tick species in the transmission of R. ricketsii to human being in the Brazilian territory.A Febre Maculosa Brasileira (FMB é uma zoonose causada por Rickettsia rickettsii e transmitida por carrapatos do gênero Amblyomma, mais freqüentemente pela espécie Amblyomma cajennense. Este

  17. Efficient Approaches for Designing Fault Tolerant Reversible Carry Look-Ahead and Carry-Skip Adders

    CERN Document Server

    Islam, Md Saiful; begum, Zerina; Hafiz, Mohd Zulfiquar

    2010-01-01

    Combinational or Classical logic circuits dissipate heat for every bit of information that is lost. Information is lost when the input vector cannot be recovered from its corresponding output vector. Reversible logic circuit implements only the functions having one-to-one mapping between its input and output vectors and therefore naturally takes care of heating. Reversible logic design becomes one of the promising research directions in low power dissipating circuit design in the past few years and has found its application in low power CMOS design, digital signal processing and nanotechnology. This paper presents the efficient approaches for designing fault tolerant reversible fast adders that implement carry look-ahead and carry-skip logic. The proposed high speed reversible adders include MIG gates for the realization of its basic building block. The MIG gate is universal and parity preserving. It allows any fault that affects no more than a single signal readily detectable at the circuit's primary outputs...

  18. Rocky Mountain spotted fever

    Science.gov (United States)

    ... Mountain spotted fever is caused by the bacteria Rickettsia rickettsii (R. Rickettsii) , which is carried by ticks. ... Saunders; 2014:chap 212. Walker DH, Blaton LS. Rickettsia rickettsii and other spotted fever group rickettsiae (Rocky ...

  19. Fault tolerant reversible logic synthesis: Carry look-ahead and carry-skip adders

    CERN Document Server

    Islam, Md Saiful; Begum, Zerina; Hafiz, Mohd Zulfiquar; 10.1109/ACTEA.2009.5227871

    2010-01-01

    Irreversible logic circuits dissipate heat for every bit of information that is lost. Information is lost when the input vector cannot be recovered from its corresponding output vector. Reversible logic circuit naturally takes care of heating because it implements only the functions that have one-to-one mapping between its input and output vectors. Therefore reversible logic design becomes one of the promising research directions in low power dissipating circuit design in the past few years and has found its application in low power CMOS design, digital signal processing and nanotechnology. This paper presents the efficient approaches for designing reversible fast adders that implement carry look-ahead and carry-skip logic. The proposed 16-bit high speed reversible adder will include IG gates for the realization of its basic building block. The IG gate is universal in the sense that it can be used to synthesize any arbitrary Boolean-functions. The IG gate is parity preserving, that is, the parity of the input...

  20. Molecular detection of spotted fever group rickettsia in Dermacentor silvarum from the Xunke Area,China%黑龙江逊克地区森林革蜱斑点热立克次体 DNA的检测

    Institute of Scientific and Technical Information of China (English)

    冯立; 王卓; 杨军; 于淼; 王立强; 邱广斌; 翟如波; 吴益民

    2014-01-01

    目的:调查黑龙江逊克地区蜱传斑点热自然疫源地,发现该地区蜱携带斑点热立克次体的种类。方法采用斑点热立克次体ompA和gltA 基因特异的PCR ,检测该地区森林革蜱的DNA样本,并对扩得阳性产物进行测序和聚类分析。结果从60只森林革蜱中检测有14只扩得斑点热立克次体ompA和gltA 基因片段,阳性率为23.33%。随机选择2只蜱的阳性片段进行测序,二者同源性为100%,ompA基因序列与Rickettsia sp .JL-02同源性为99.30%,与 Rickettsia raoultii为99.18%。结论黑龙江省逊克地区森林革蜱携带与 Rickettsia sp .JL-02株亲缘关系相近的斑点热群立克次体。%To identify the prevalence and the distribution of ticks infected with spotted fever group rickettsiae (SFGR) in Xunke Area of Heilongjiang Province ,China ,partial outer membrane protein A gene (ompA) and citrate synthase gene (gltA) specific fragments were assessed using the PCR method .The positive products were sequenced .Result showed that the pres-ence of SFGR was 14 of 60 in detection Dermacentor silvarum cases ,while the overall positive rate was 23 .33% .Its nucleotide sequence of ompA showed 99 .3% and 99 .18% similarity with nucleotide sequence of Rickettsia sp .JL-02 and Rickettsia rao-ultii respectively .And the evolutionary positions of SFGR species were similar with Rickettsiamontana and Rickettsiamassili-ae .It's concluded that the nature focus of tick-borne spotted fever did exist in the area of Xunke Area of Heilongjiang Province , China .

  1. 中哈边境口岸臀突客蚤检出立克次氏体核酸%Rickettsia isolated from Xenopsylla minax at China-Kazakh border

    Institute of Scientific and Technical Information of China (English)

    罗丹; 尹小平; 王安东; 田延河; 梁臻; 巴特; 张江国

    2016-01-01

    目的 了解中哈边境地区臀突客蚤(Xenopsylla minax)中立克次氏体携带情况.方法 收集阿拉山口口岸臀突客蚤样本,PCR扩增立克次体17 kDa基因片段,PCR产物测序并BLAST比对,利用Mega 6.0构建分子遗传进化树.结果 42.86% (3/7)的臀突客蚤携带立克次体,17 kDa基因遗传进化树显示与Candidatus Rickettsia senegalensis和Rickettsia bellii同源性最高.结论 中哈边境口岸地区臀突客蚤携带立克次体核酸.

  2. Carrying Capacity of Marine Region in Liaoning Province

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Carrying capacity is one of important studies on coordinating development of population, resources, and environment. At present, the researches on it mainly concentrate on the carrying capacity for population and economy,such as the water resources carrying capacity, the land resources carrying capacity, the environment carrying capacity,etc. Based on the related theories and methods, this paper creatively proposed the concept and meaning of carrying capacity of marine region, and formed the appraisal system. According to the developing situation of marine economy of Liaoning Province in recent years, and by employing the method of the state space, this paper also measured the cartying capacity and carrying state of marine region and discussed the sustainable problems of marine economy of Liaoning. The research results show that the carrying state of marine region of Liaoning is in the state of overloading at present, but taking a favorable turn.

  3. Delay Efficient 32-Bit Carry-Skip Adder

    OpenAIRE

    Yu Shen Lin; Damu Radhakrishnan

    2008-01-01

    The design of a 32-bit carry-skip adder to achieve minimum delay is presented in this paper. A fast carry look-ahead logic using group generate and group propagate functions is used to speed up the performance of multiple stages of ripple carry adders. The group generate and group propagate functions are generated in parallel with the carry generation for each block. The optimum block sizes are decided by considering the critical path into account. The new architecture ...

  4. 46 CFR 111.105-35 - Vessels carrying coal.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Vessels carrying coal. 111.105-35 Section 111.105-35...-GENERAL REQUIREMENTS Hazardous Locations § 111.105-35 Vessels carrying coal. (a) The following are Class II, Division 1, (Zone 10 or Z) locations on a vessel that carries coal: (1) The interior of each...

  5. 49 CFR 177.870 - Regulations for passenger carrying vehicles.

    Science.gov (United States)

    2010-10-01

    ... be transported by passenger-carrying aircraft or rail car may be transported on a motor vehicle... PUBLIC HIGHWAY Regulations Applying to Hazardous Material on Motor Vehicles Carrying Passengers for Hire... authorized by parts 170-189 of this subchapter to be transported on motor vehicles carrying passengers...

  6. Interpretations of the Image of Caroline in Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    钱绘

    2014-01-01

    In the history of American naturalistic literature, Sister Carrie is a representative work of this literary genre. And the protagonist of this novel Caroline has always been a controversial character. Based on Sister Carrie and the social background of that period in America, this paper discussed the various interpretations of the image of Carrie from different aspects.

  7. Study of the Five Rickettsia prowazekii Proteins Annotated as ATP/ADP Translocases (Tlc): Only Tlc1 Transports ATP/ADP, While Tlc4 and Tlc5 Transport Other Ribonucleotides

    OpenAIRE

    Audia, Jonathon P.; Winkler, Herbert H.

    2006-01-01

    The obligate intracytoplasmic pathogen Rickettsia prowazekii relies on the transport of many essential compounds from the cytoplasm of the eukaryotic host cell in lieu of de novo synthesis, an evolutionary outcome undoubtedly linked to obligatory growth in this metabolite-replete niche. The paradigm for the study of rickettsial transport systems is the ATP/ADP translocase Tlc1, which exchanges bacterial ADP for host cell ATP as a source of energy, rather than as a source of adenylate. Interes...

  8. Delay Efficient 32-Bit Carry-Skip Adder

    Directory of Open Access Journals (Sweden)

    Yu Shen Lin

    2008-01-01

    Full Text Available The design of a 32-bit carry-skip adder to achieve minimum delay is presented in this paper. A fast carry look-ahead logic using group generate and group propagate functions is used to speed up the performance of multiple stages of ripple carry adders. The group generate and group propagate functions are generated in parallel with the carry generation for each block. The optimum block sizes are decided by considering the critical path into account. The new architecture delivers the sum and carry outputs in lesser unit delays than existing carry-skip adders. The adder is implemented in 0.25 m CMOS technology at 3.3 V. The critical delay for the proposed adder is 3.4 nanoseconds. The simulation results show that the proposed adder is 18% faster than the current fastest carry-skip adder.

  9. Regional carrying capacity: case studies of Bohai Rim area

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Carrying capacity research has been carried out for a long time. However, synthesized carrying capacity researches based on systematic views began only in the 1970s. There is even less work done in China. This paper tries to address both synthesized carrying capacity research and its utilization in China. State spaces method from the systematic science was borrowed to construct the conceptual model of regional carrying capacity. Based on the conceptual model and the surveys in the Bohai Rim area, we construct a representative indicators system for quantifying regional carrying capacity in the Bohai Rim. While employing system dynamic models we simulated the evolving trend of both the regional carrying states and regional carrying capacity from 1999 to 2015. The results proved the statement that Bohai Rim is overall over-capacity for a long time and will be over-capacity in the foreseeable future. Among all the restriction factors, water shortage and environmental pollution stand out to be the two primary obstacles for Bohai Rim's sustainable development.Regional differentiation analysis further indicates that coastal areas of the Bohai Rim burden more than its overall level. However, Shandong province shows some good signs in addressing the regional carrying capacity issues. The research is successful in addressing the quantification of regional carrying capacity issues, but nonetheless it needs further refinery and more information.

  10. 黑龙江立克次体感染血管内皮细胞的初步研究%Primary study on Rickettsia heilongjiangensis infection of vascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    孟艳芬; 段长松; 王锡乐; 熊小路; 温博海

    2011-01-01

    The Rickettsia heilongjiangensis organisms purified by Renografin renografin gradient centrifugation were applied to infected human umbilical vein endothelial cells (HUVEC) grown in monolayer on cover slips. Rickettsiae were examined by both indirect immune fluorescence assay (IFA) and scanning electron micrograph (SEM) after rickettsial infection.During the first 24 hours postinfection (ip), two infection peaks were found at 6 and 24 hours pi, respectively. Multiplication of rickettsiae and pathological changes of host cells were observed at 5 days pi, while the amount of intracellular rickettsiae was markedly increased within 5 to 9 days pi. A few of rickettsiae were observed in the nucleus of host cells that appeared severe pathological changes within 8 to 9 days pi. Due to the overwhelming rickettsial infection, most of the infected host cells shed 12 days pi. Our results demonstrated that R. heilongjiangensis has a capability to infect vascular endothelial cells to cause vascular injury of humans.%目的 通过黑龙江立克次体感染体外培养人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVEC)探讨其在内皮细胞内的生长规律.方法 将泛影葡胺密度梯度超速离心纯化的黑龙江立克次体(HLJ-054株)感染体外培养的HUVEC,通过间接免疫荧光和扫描电镜检测与观察不同时相黑龙江立克次体在内皮细胞内的生长状况.热灭活黑龙江立克次体做平行对照.结果 立克次体粘附并侵入内皮细胞,在感染后第6 h及第24 h分别为感染高峰;感染5 d后细胞内立克次体逐渐增殖,第8~9 d细胞内立克次体急剧增殖,并见细胞核内有少量立克次体,细胞出现病变,第12 d细胞内充满立克次体,大部分细胞皱缩脱落.结论 黑龙江立克次体能够感染血管内皮细胞,在血管内皮细胞内不断增殖而使细胞死亡.

  11. 唐山地区蜱传斑点热群立克次体分子流行病学%Molecular epidemiological of spotted fever group Rickettsia from ticks in Tangshan area

    Institute of Scientific and Technical Information of China (English)

    邹亚学; 贾青辉; 刘朋朋; 刘全; 高宏伟; 陈丽凤

    2011-01-01

    Two sets of specific primers,designed according to 16SrRNA for tick and the OmpA gene specific for spotted fever group Rickettsia(SFGR),were used to amplify 16SrRNA and OmpA gene from DNA samples extracted from Haemaphysalis longicornis in Tangshan area.The positive samples were sequenced and genetically analyzed by establishment of phylogenetic tree.Of 315 samples,25 samples were positive for SFGR and the infection rate reached to 7.94%.Phylogenetic analysis based on nucleotide sequence revealed that all positive strains were related and clustered together with Rickettsia sp.Japanese strain(93.30%),Rickettsia sp.Fujian strain(92.11%),Rickettsia sp.suifen strain(90.45%) and Rickettsia sp.Hulin strain(90.42%).The infection of spotted fever group Rickettsia in Tangshan area was serious,and the bacterium may be a novel species.%根据已发表的长角血蜱16SrRNA序列及斑点热群立克次体外膜蛋白A(OmpA)基因序列设计2对特异性引物,对唐山地区采集的长角血蜱进行PCR检测,并对阳性样本进行测序和序列分析,抽检样本建立分子系统进化树。结果表明,在315份蜱DNA样本中检测出25份阳性样本,阳性率为7.94%;序列分析结果显示唐山地区长角血蜱携带立克次体同处于一个分支,与日本株立克次体同源性最高(93.30%),其次是福建株立克次体(92.11%),黑龙江立克次体绥芬株(90.45%)、虎林株(90.42%)。结论得出唐山地区蜱传斑点热感染较严重,分子进化分析结果显示唐山地区蜱传斑点热群立克次体可能为一新种。

  12. High performance pipelined multiplier with fast carry-save adder

    Science.gov (United States)

    Wu, Angus

    1990-01-01

    A high-performance pipelined multiplier is described. Its high performance results from the fast carry-save adder basic cell which has a simple structure and is suitable for the Gate Forest semi-custom environment. The carry-save adder computes the sum and carry within two gate delay. Results show that the proposed adder can operate at 200 MHz for a 2-micron CMOS process; better performance is expected in a Gate Forest realization.

  13. Trusted Module Acquisition Through Proof-Carrying Hardware Intellectual Property

    Science.gov (United States)

    2015-05-22

    hardware intellectual property (PCHIP) framework, which aims to ensure the trustworthiness of third-party hardware IPs utilizing formal methods. We...published in non peer-reviewed journals: Final Report: Trusted Module Acquisition Through Proof-Carrying Hardware Intellectual Property Report Title By...borrowing ideas from the proof carrying code (PCC) in software domain, in this project we introduced the proof carrying hardware intellectual property

  14. Optimal design method for fast carry-skip adders

    Science.gov (United States)

    Lee, Songjun; Swartzlander, Earl E., Jr.

    2001-11-01

    A carry-skip adder is faster than a ripple carry adder and it has a simple structure. To maximize the speed it is necessary to optimize the width of the blocks that comprise the carry skip adder. This paper presents a simple algorithm to select the size of each block. Assuming that each logic gate has a unit delay, the algorithm achieves slightly faster designs for 64 and 128 bit adders than previous methods developed by Guyot, et al. and Kantabutra.

  15. Magnetically Guiding Atoms with Current-Carrying Conductors

    Institute of Scientific and Technical Information of China (English)

    刘南春; 高伟建; 印建平

    2002-01-01

    We propose a novel magnetic guide for cold neutral atoms using some current-carrying conductors. The spatial distributions of the magnetic fields from a V-shaped or U-shaped current-carrying conductor are calculated, and the relationship between the resulting magnetic field and the parameters of the current-carrying conductors is analysed in detail. The result shows that these current-carrying conductors can be used to realize a single or a controllable double magnetic guide of cold atoms in the weak-field-seeking state, and to construct various atom-optical elements, and even to realize a single-mode atomic waveguiding under certain conditions.

  16. Organization and carrying out the triathlon competitions in Ukraine

    Directory of Open Access Journals (Sweden)

    Volodymyr Vodlozerov

    2016-02-01

    Full Text Available Purpose: the aim is analyzing of system of organization and carrying out the triathlon competitions in Ukraine in accordance with rules of triathlon international federation. Material & Methods: comparative analysis of process of organization and carrying out the triathlon competitions in the world and Ukraine was carried out on basis of specialist literature studying, normative base of sports organizations (triathlon federation. Results: inconsistencies were identified in competitions carried out in cold season, particularity of triathlon that intends overcoming the combined distance without time durations between stages. Conclusions: recommendation in eliminate inconsistencies that affect to performance of triathlon competitions in Ukraine was suggested.

  17. Protective immunity against Rickettsia heilongjiangensis in a C3H/HeN mouse model mediated by outer membrane protein B-pulsed dendritic cells.

    Science.gov (United States)

    Meng, YanFen; Xiong, XiaoLu; Qi, Yong; Duan, ChangSong; Gong, WenPing; Jiao, Jun; Wen, BoHai

    2015-03-01

    Rickettsia heilongjiangensis is an obligate intracellular bacterium that causes Far-Eastern tick-borne spotted fever. Outer membrane protein B (OmpB) is an important surface protein antigen of rickettsiae. In the present study, the ompB gene of R. heilongjiangensis was divided into four fragments, resulting in four recombinant proteins (OmpB-p1, OmpB-p2, OmpB-p3, and OmpB-p4). Each OmpB was used in vitro to stimulate murine bone marrow-derived dendritic cells (BMDCs) of C3H/HeN mice, and the OmpB-pulsed BMDCs were transferred to naïve C3H/HeN mice. On day 14 post-transfer of BMDCs, the mice were challenged with R. heilongjiangensis and the rickettsial loads in the mice were quantitatively determined on day 7 post-challenge. Mice receiving BMDCs pulsed with OmpB-p2, OmpB-p3, or OmpB-p4 exhibited significantly lower bacterial load compared with mice receiving OmpB-p1-pulsed BMDCs. CD4(+) and CD8(+) T cells isolated from the spleen of C3H/HeN mice receiving BMDCs pulsed with each OmpB were co-cultured with BMDCs pulsed with the respective cognate protein. In flow cytometric analysis, the expression level of CD69 on CD4(+) or CD8(+) T cells from mice receiving BMDCs pulsed with OmpB-p2, OmpB-p3, or OmpB-p4 was higher than that on cells from mice receiving OmpB-p1-pulsed BMDCs, while the expression level of tumor necrosis factor (TNF)-α on CD8(+) T cells and interferon (IFN)-γ on the CD4(+) and CD8(+) T cells from mice receiving OmpB-p2, -p3, or -p4 was significantly higher than on cells from mice receiving OmpB-p1-pulsed BMDCs. Our results suggest that the protective OmpBs could activate CD4(+) and CD8(+) T cells and drive their differentiation toward CD4(+) Th1 and CD8(+) Tcl cells, respectively, which produce greater amounts of TNF-α and, in particular, IFN-γ, to enhance rickettsicidal activity of host cells.

  18. Serological identification of Rickettsia spp from the spotted fever group in capybaras in the region of Campinas - SP - Brazil Identificação sorológica de Rickettsia spp do grupo da febre maculosa em capivaras na região de Campinas, SP, Brasil

    Directory of Open Access Journals (Sweden)

    Celso Eduardo de Souza

    2008-09-01

    Full Text Available Diseases transmitted by ticks have been an important health problem all over the world. Brazilian Spotted Fever (BSF stands for a serious epidemiological concern due to the high mortality rates pointed out. Capybaras are commonly incriminated as possible reservoirs in the BSF transmission cycle. In the last decades the numbers of these animals raised sharply and they have invaded human areas. They intensify the contact between ticks and humans beings. This study aim is to contribute to the possible role performed for this rodent in the BSF epidemiology in some areas located in Campinas region, São Paulo. Cabybaras infected by rickettsiae of BSF group were studied through the analysis of the frequencies of BSF-group rickettisae antibodies titer = 64 by indirect immunofluorescence test (IFA, and data from human cases epidemiological surveillance. The serum frequency positiveness varied greatly according to areas where animals were captured. However it was found serum positiviness only in the areas where human cases of BSF were reported. These findings suggest the capybara may be seen as sentinel animal. Due to presence of serological cross reactivity between microorganisms belonging to SF group, the results must be interpreted carefully and additional methods to distinguish pathogenic rickettsiae are required in our country.Doenças transmitidas por carrapatos vêm sendo um importante problema de saúde pública no mundo. A Febre Maculosa Brasileira (FMB representa um sério risco epidemiológico devido às altas taxas de letalidade apresentadas. As capivaras são freqüentemente incriminadas como possíveis reservatórios no ciclo de transmissão da FMB. Nas últimas décadas o número desses animais cresceu intensamente e eles invadiram os espaços humanos. As capivaras intensificam o contato entre carrapatos e seres humanos na medida em que se apresentam muito infestadas por estes parasitos. O objetivo deste estudo é contribuir para o

  19. The Disillusion of American Dream in Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    张晴

    2016-01-01

    Dreiser is a generally acknowledged writer as one of American's literary naturalists. In Sister Carrie, the author skillfully used the naturalistic writing style which incisively and vividly showed the society environment at that time. The paper states the process that how the American dream in Sister Carrie disillusioned gradually.

  20. 25 CFR 11.444 - Carrying concealed weapons.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Carrying concealed weapons. 11.444 Section 11.444 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER COURTS OF INDIAN OFFENSES AND LAW AND ORDER CODE Criminal Offenses § 11.444 Carrying concealed weapons. A person who goes about in...

  1. 46 CFR 185.340 - Vessels carrying vehicles.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Vessels carrying vehicles. 185.340 Section 185.340... TONS) OPERATIONS Miscellaneous Operating Requirements § 185.340 Vessels carrying vehicles. (a) Automobiles or other vehicles must be stowed in such a manner as to permit both passengers and crew to get...

  2. 46 CFR 122.340 - Vessels carrying vehicles.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Vessels carrying vehicles. 122.340 Section 122.340... Miscellaneous Operating Requirements § 122.340 Vessels carrying vehicles. (a) Automobiles or other vehicles must... vehicles freely in the event of fire or other disaster. The decks, where necessary, must be...

  3. Detection of Rickettsia rickettsii in the tick Amblyomma cajennense in a new Brazilian spotted fever-endemic area in the state of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Elizângela Guedes

    2005-12-01

    Full Text Available The present study evaluated rickettsial infection in Amblyomma spp. ticks collected in a farm in Coronel Pacheco, a Brazilian spotted fever (BSF endemic area. A total of 78 A. cajennense and 78 A. dubitatum free-living adult ticks were collected and tested by polymerase chain reaction (PCR targeting a fragment of the rickettsial gene gltA. Only one pool of three A. cajennense ticks showed the expected product by PCR. This pool was further tested by PCR using sets of primers targeting the rickettsial genes gltA, ompA, and ompB. All reactions yielded the expected bands that by sequencing, showed 100% identity to the corresponding sequences of the Rickettsia rickettsii gene fragments gltA (1063-bp, ompA (457-bp, and ompB (720-bp. The minimal infection rate of R. rickettii in the A. cajennense population was 1.28% (at least one infected tick within 78 ticks.The present study showed molecular evidence for the presence of R. rickettsii in A. cajennense from a BSF-endemic area in Coronel Pacheco, state of Minas Gerais. Although R. rickettsii has been previously reported infecting A. cajennense ticks in Brazil and other Latin American countries, the present study performed the first molecular characterization of R. rickettsii from the tick A. cajennense.

  4. Detection of Rickettsia rickettsii in the tick Amblyomma cajennense in a new Brazilian spotted fever-endemic area in the state of Minas Gerais.

    Science.gov (United States)

    Guedes, Elizângela; Leite, Romário C; Prata, Márcia C A; Pacheco, Richard C; Walker, David H; Labruna, Marcelo B

    2005-12-01

    The present study evaluated rickettsial infection in Amblyomma spp. ticks collected in a farm in Coronel Pacheco, a Brazilian spotted fever (BSF) endemic area. A total of 78 A. cajennense and 78 A. dubitatum free-living adult ticks were collected and tested by polymerase chain reaction (PCR) targeting a fragment of the rickettsial gene gltA. Only one pool of three A. cajennense ticks showed the expected product by PCR. This pool was further tested by PCR using sets of primers targeting the rickettsial genes gltA, ompA, and ompB. All reactions yielded the expected bands that by sequencing, showed 100% identity to the corresponding sequences of the Rickettsia rickettsii gene fragments gltA (1063-bp), ompA (457-bp), and ompB (720-bp). The minimal infection rate of R. rickettii in the A. cajennense population was 1.28% (at least one infected tick within 78 ticks). The present study showed molecular evidence for the presence of R. rickettsii in A. cajennense from a BSF-endemic area in Coronel Pacheco, state of Minas Gerais. Although R. rickettsii has been previously reported infecting A. cajennense ticks in Brazil and other Latin American countries, the present study performed the first molecular characterization of R. rickettsii from the tick A. cajennense.

  5. In vitro isolation and infection intensity of Rickettsia parkeri in Amblyomma triste ticks from the Paraná River Delta region, Argentina.

    Science.gov (United States)

    Monje, Lucas D; Nava, Santiago; Antoniazzi, Leandro R; Colombo, Valeria C; Beldomenico, Pablo M

    2014-10-01

    In the present study, we report the first in vitro isolation and infection intensity of Rickettsia parkeri in Amblyomma triste ticks from Argentina. No genetic differences in the molecular targets evaluated were found between R. parkeri isolates from Argentina and those R. parkeri isolates reported in Uruguay and Brazil, both obtained from A. triste. Only a minor difference was observed when compared to R. parkeri isolated from Amblyomma maculatum from United States. Moreover, the prevalence of infection by R. parkeri in ticks collected from the vegetation in the Paraná Delta was high (20.4%). Interestingly, the distribution of R. parkeri infection intensity observed in A. triste ticks was distinctly bimodal, with approximately 60% of the infected ticks presenting high rickettsial loads (3.8×10(5)-4.5×10(7) ompA copies/tick) and the remainder with low rickettsial levels (5.6×10(1)-6.5×10(3) ompA copies/tick). This bimodality in R. parkeri infection intensity in ticks could determine differences in the severity of the disease, but also be important for the infection dynamics of this pathogen. Further research exploring the distribution of rickettsial infection levels in ticks, as well as its determinants and implications, is warranted.

  6. Global change and carrying capacity: Implications for life on Earth

    Science.gov (United States)

    Ehrlich, Paul R.; Daily, Gretchen C.; Ehrlich, Anne H.; Matson, Pamela; Vitousek, Peter

    1989-01-01

    Determining the long-term number of people that the planet can support without irreversibly reducing its ability to support people in the future, i.e., the carrying capacity of the Earth, is an exceedingly complex problem. About all that is known for certain is that, with present and foreseeable technologies, the human population has already exceeded the capacity. The reduction in carrying capacity that can be expected to result from direct human impacts on resources and the environment and from our indirect impacts of the climate system is discussed. Global warming and modeling global change and food security are also discussed with respect to carrying capacity.

  7. Research on Psychological Carrying Capacity of Tourism Destination

    Institute of Scientific and Technical Information of China (English)

    Fan Zhiyong; Zhong Sheng

    2009-01-01

    As a part of the carrying capacity system of tourism destination,tourism psychological carrying capacity and its makeup are very important indexes which reflect the harmonious development of tourism destination develops harmoniously,but the academy has not paid enough attention to them.Based on the concept and connotation of psychological carrying capacity,this paper explains the influencing factors which affect the psychological capacity of the tourist and the resident after the acknowledged concept,and then designs a harmonious development model of tourism destination.Finally,it offers some countermeasures against the overloading psychological capacity.

  8. Measuring the Magnetic Force on a Current-Carrying Conductor.

    Science.gov (United States)

    Herreman, W.; Huysentruyt, R.

    1995-01-01

    Describes a fast and simple method for measuring the magnetic force acting on a current-carrying conductor using a digital balance. Discusses the influence of current intensity and wire length on the magnetic force on the conductor. (JRH)

  9. Determination of the sediment carrying capacity based on perturbed theory.

    Science.gov (United States)

    Ni, Zhi-hui; Zeng, Qiang; Li-chun, Wu

    2014-01-01

    According to the previous studies of sediment carrying capacity, a new method of sediment carrying capacity on perturbed theory was proposed. By taking into account the average water depth, average flow velocity, settling velocity, and other influencing factors and introducing the median grain size as one main influencing factor in deriving the new formula, we established a new sediment carrying capacity formula. The coefficients were determined by the principle of dimensional analysis, multiple linear regression method, and the least square method. After that, the new formula was verified through measuring data of natural rivers and flume tests and comparing the verified results calculated by Cao Formula, Zhang Formula, Li Formula, Engelung-Hansen Formula, Ackers-White Formula, and Yang Formula. According to the compared results, it can be seen that the new method is of high accuracy. It could be a useful reference for the determination of sediment carrying capacity.

  10. Lane of parallel through carry in ternary optical adder

    Institute of Scientific and Technical Information of China (English)

    JIN Yi; HE Huacan; AI Lirong

    2005-01-01

    At the present 50 to 100 microseconds are necessary for a liquid crystal to change its state from opacity to clarity; 1.14× 10-5 microseconds are however proved to be enough for light to pass through a clarity liquid crystal device. Rooted from this great difference in time, an optical adder was constructed with parallel through carry lanes (PTCL) composed of liquid crystals. Because all carries in PTCL process in parallel, the carry delay in the ternary optical computer's adder is avoided. Eliminating the carry delay in adder of ternary optical computer by physical means, the PTCL is also applicable for other types of optical adders. Moreover a light diagram of the adder and one PTCL structure are provided.

  11. Carrying Network Accessing Architecture and Strategy Based on Business Differentiation

    Directory of Open Access Journals (Sweden)

    Yanyan Han

    2013-07-01

    Full Text Available Due to the abilities of real-time sensing and information sharing, Wireless Sensor Network (WSN has been applied in more and more fields. Basing on the emergence of Internet of Things (IoT, the issue about heterogeneous network integration is becoming more important. We first analyze the new businesses that arise recently for cell phone users as well as the potential effect on carrying network. After that we mainly discuss the influence on traditional carrying network for WSN accessing and taking concurrent businesses as the study case, common access architecture from WSN to carrying network is constructed, which makes use of business differentiation. Furthermore, we propose the idea of tortuous access from WSN to the gateway in the carrying network to avoid congested paths with simulation and verification. Finally, we conclude the possible impacts for the integration of these two networks and present possible solutions.

  12. Estimating the recreational carrying capacity of a lowland river section.

    Science.gov (United States)

    Lorenz, Stefan; Pusch, Martin T

    2012-01-01

    Recreational boating represents a major human use of inland waters in many regions. However, boating tourism may affect the ecological integrity of surface waters in multiple ways. In particular, surface waves produced by boating may disturb freshwater invertebrates, such as interrupting the filtration activity of benthic mussels. As mussels may significantly contribute to self-purification, disturbance may have crucial impacts on water quality, and thus on water tourism. In this paper we calculate the carrying capacity of a river section for sustainable boating tourism based on the preservation of water quality. This approach is complemented by spatial and social approaches for carrying capacity estimates. The ecological carrying capacity significantly decreases with lower water levels during summer. Hence, the analysis of variables that influence the river's carrying capacity allows the formation of recommendations for management measures that integrate social, touristic and ecological aspects.

  13. Study on Tourist Carrying Capacity Based on Matter Element Analysis

    Institute of Scientific and Technical Information of China (English)

    LiuYunguo; FanTing; LiXin; ZhouMing; WangXianhai

    2005-01-01

    This paper proposes that it is necessary to implement the concept of tourist carrying capacity to facilitate the tourism planning, and presents a method to evaluate the carrying capacity. The method called matter element analysis can solve the uncertain and incompatible problem of the evaluated factors in assessing carrying capacity.The current state of a destination's carrying capacity can be determined by establishing the standard indexes and the matter element model. Through the evaluating of the travel industry zones of the Autonomous Prefecture of Western Hunan, the method is proved to be simple and feasible, and it is improved to be significant for the tourism planning and determination as well as the sustainable development of the regional tourism.

  14. Design and Implementation of High Speed Carry Select Adder

    OpenAIRE

    B. Gopinath; N Sangeetha; S.Jenifer nancy; T.Umarani

    2015-01-01

    In electronic adder is a digital circuit that performs addition of numbers. Adders can be constructed for many numerical representations such as arithmetic and logical operation. The most adders operates on binary numbers. Among the different types of adders, carry select adder is a one of the fastest adder.The gate level modification is to reduce the power and area of carry select adder by using the concept of Arithmetic Logic Unit (ALU). In this paper , different techniques such as Binary T...

  15. The Construction of Social Darwinism in Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    薛晶晶; 秦素华

    2014-01-01

    Social Darwinism is an important theory reflected in Sister Carrie. This thesis is to interpret the characters’fates with Social Darwinism.“Survival of the fittest”is an important theme. Carrie is the winner of life and Hurtwood is the loser. Their adjustability to the environment determines their future. It is hoped to help the readers construct a better understanding on this theory.

  16. Locomotion while load-carrying in reduced gravities.

    Science.gov (United States)

    Wickman, L A; Luna, B

    1996-10-01

    Supporting the mass of a protective suit and portable life support system (PLSS) will impose an energy requirement on planetary astronauts. To design extravehicular protective equipment for planetary missions, scientists must learn more about human physical capabilities while load-carrying in reduced gravities. In this study, an underwater treadmill and weighting system were used to simulate reduced-gravity locomotion while load-carrying. The test matrix included 3 gravity levels, 6 subjects, 2 locomotion speeds, and a range of load sizes. Energy expenditure, calculated from measured oxygen consumption, is positively correlated with gravity level, speed, and load size. The data are used to project that individuals in average physical condition will be able to walk for 8 h on the Moon while carrying up to 170% of their body mass without undue fatigue, and on Mars with up to 50% of their body mass. These approximate limits, especially for Martian gravity, may prove quite a challenge for designers of advanced protective systems. Requirements for regenerable and non-venting PLSS components have been driving the total projected masses of advanced PLSSs increasingly higher, perhaps beyond what is reasonable to carry. However, the larger mass can be beneficial in maintaining bone mass. Using Whalen's model (1988), the daily planetary walking times required to maintain bone mass were calculated for a range of carried load sizes. The calculated times were unattainably high, suggesting that some combination of loads carrying and supplemental bone maintenance measures will likely be required to maintain bone mass in reduced gravity environments.

  17. Missile captive carry monitoring using a capacitive MEMS accelerometer

    Science.gov (United States)

    Hatchell, Brian; Mauss, Fred; Santiago-Rojas, Emiliano; Amaya, Ivan; Skorpik, Jim; Silvers, Kurt; Marotta, Steve

    2010-03-01

    Military missiles are exposed to many sources of mechanical vibration that can affect system reliability, safety, and mission effectiveness. One of the most significant exposures to vibration occurs when the missile is being carried by an aviation platform, which is a condition known as captive carry. If the duration of captive carry exposure could be recorded during the missile's service life, several advantages could be realized. Missiles that have been exposed to durations outside the design envelop could be flagged or screened for maintenance or inspection; lightly exposed missiles could be selected for critical mission applications; and missile allocation to missions could be based on prior use to avoid overuse. The U. S. Army Aviation and Missile Research Development and Engineering Center (AMRDEC) has been developing health monitoring systems to assess and improve reliability of missiles during storage and field exposures. Under the direction of AMRDEC staff, engineers at the Pacific Northwest National Laboratory have developed a Captive Carry Health Monitor (CCHM) for the HELLFIRE II missile. The CCHM is an embedded usage monitoring device installed on the outer skin of the HELLFIRE II missile to record the cumulative hours the host missile has been in captive carry mode and thereby assess the overall health of the missile. This paper provides an overview of the CCHM electrical and package design, describes field testing and data analysis techniques used to identify captive carry, and discusses the potential application of missile health and usage data for real-time reliability analysis and fleet management.

  18. The Broken American Dream Based on Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    Dong Wenjuan

    2012-01-01

      Sister Carrie is the first work of Theodore Dreiser, It tells us how a country maiden becomes a famous star in Broadway. In the novel, Dreiser describes the living conditions and emotion changes of Carrie very vividly. Sister Carrie takes true realism as its distinctive feature, reflects the tragic fact that people pursue American dream fanatically in the early twentieth century. This paper exposes the theme of instinct, which drives people to enjoy but disillusion finally, and illustrates that it is impossible to possess true happiness in a money-oriented capitalism society%  Sister Carrie is the first work of Theodore Dreiser, Ittells us how a country maiden becomes a famous star in Broadway.In the novel, Dreiser describes the living conditions and emotion changes of Carrie very vividly. Sister Carrie takes true realism as itsdistinctive feature, reflects the tragic fact that people pursue Americandream fanatically in the early twentieth century. This paper exposes the theme of instinct, which drives people to enjoy but disillusion finally, and illustrates that it is impossible to possess true happiness in a money-oriented capitalism society

  19. Missile Captive Carry Monitoring using a Capacitive MEMS Accelerometer

    Energy Technology Data Exchange (ETDEWEB)

    Hatchell, Brian K.; Mauss, Fredrick J.; Santiago-Rojas, Emiliano; Amaya, Ivan A.; Skorpik, James R.; Silvers, Kurt L.; Marotta, Steve

    2010-04-08

    Military missiles are exposed to many sources of mechanical vibration that can affect system reliability, safety, and mission effectiveness. One of the most significant exposures to vibration occurs when the missile is being carried by an aviation platform, which is a condition known as captive carry. If the duration of captive carry exposure could be recorded during the missile’s service life, several advantages could be realized. Missiles that have been exposed to durations outside the design envelop could be flagged or screened for maintenance or inspection; lightly exposed missiles could be selected for critical mission applications; and missile allocation to missions could be based on prior use to avoid overuse. The U. S. Army Aviation and Missile Research Development and Engineering Center (AMRDEC) has been developing health monitoring systems to assess and improve reliability of missiles during storage and field exposures. Under the direction of AMRDEC staff, engineers at the Pacific Northwest National Laboratory have developed a Captive Carry Health Monitor (CCHM) for the HELLFIRE II missile. The CCHM is an embedded usage monitoring device installed on the outer skin of the HELLFIRE II missile to record the cumulative hours the host missile has been in captive carry mode and thereby assess the overall health of the missile. This paper provides an overview of the CCHM electrical and package design, describes field testing and data analysis techniques used to identify captive carry, and discusses the potential application of missile health and usage data for real-time reliability analysis and fleet management.

  20. Model Modification and Application on Carrying Capacity of Relative Resources

    Institute of Scientific and Technical Information of China (English)

    Li Zehong; Dong Suocheng; Gao Dan

    2009-01-01

    Based on the retrospection of researches on carry-ing capacity, this article reviewed systematically the research progresses on carrying capacity of relative resources (CCRR).Then the viewpoint was put forward that CCRR is not an ap-propriate method of appraising the regional sustainability, but a sound way to obtain cognition for coordinating spatial loca-tion and flow of population and economy.However, as the most popular computing method of CCRR, the Weighting Linear Sum Model is defective in the random of weight choice and the neglect of matching among different resources.Therefore, this article established the Geometric Model on CCRR based on modifying Weighting Linear Sum Model, which can be used to appraise regions where resources are close matching.Em-ploying the Geometric Model, the article empirically analyzed the population and economic CCRR in Hubei Province from 1978 to 2006.The result indicates that the population in Hubei Province is overloading while the economic carrying capacity is abundant compared to the whole country, and the economic insufficiency restricts the population carrying capacity.In the future, Hubei Province will become one of the core developing zones which are characterized by economic conglomeration.

  1. Epidemiología de rickettsiosis por Rickettsia parkeri y otras especies emergentes o re-emergentes asociadas a la antropización en Latinoamérica

    Directory of Open Access Journals (Sweden)

    José M Venzal

    2013-07-01

    Full Text Available Se describe la importancia regional de Rickettsia parkeri y sus respectivos vectores. Se hace énfasis en los factores de antropización que favorecen la aparición de hospedadores alternativos para las garrapatas en los entornos domésticos y peridomésticos, generando modificaciones en la epidemiología del agente etiológico. También se menciona las modificaciones ecológicas que pueden favorecen el incremento de poblaciones de reservorios para las garrapatas incrementando el riesgo para el ser humano de sufrir enfermedades rickettsiales.

  2. 酿酒酵母线粒体蛋白转运系统在立克次体中的同源分析%The homology analysis of Saccharomyces cerevisiae mitochondrial protein import machinery in Rickettsia prowazekii

    Institute of Scientific and Technical Information of China (English)

    刘震; 李校; 赵培虎; 桂俊鸿; 张义正

    2011-01-01

    进化分析表明,与线粒体亲缘关系最近的原核生物是立克次体(Rickettsia prowazekii).搜索酿酒酵母(Saccharom ycescerevisia)线粒体蛋白转运系统的35个亚基在立克次体中的同源蛋白质,仅发现了5个同源蛋白,且它们只属于转运系统在线粒体外膜和基质上的模块,没有发现转运系统在膜间隙和内膜模块的同源蛋白.对大肠杆菌(Escherichia coli K-12 MG1655)的分析也有类似的结果.因此线粒体蛋白转运系统应该不是直接起源于内共生的原核生物.%ConA from 0 μg/mL to 100 μg/mL was added into Tca8113 cells, and MTT, cellular mor phology observation, LDH assay, flow cytometry detection and caspase assay were performed. MTT was applied to detect the inhibitory ratio of Tca8113 cells, and-morphologic changes, LDH, flow cytom etry detection were applied to detect apoptosis. In addition, caspase assy was also applied to observe whether caspase was involved in ConA-induced apoptosis in Tca8113 cells. After 24 h incubation with 25 μg/mL ConA, the inhibitory rate reached nearly 50%. Typical morphologic changes like membrane blebbing, chromatin condensation and nuclei fragmentation were confirmed. LDH assay and flow cytom etry detection showed that with the progressively increasing the concentration of ConA, more and more apoptotic cells appeared. And, caspase assay demonstrated that ConA could induce apoptosis in Tca8113 Phylogenetic analyses identified that Rickettsia prowazekii is the closest relatives of modern mitochondria. The homology analysis results from the 35 subunits of mitochondrial protein import mechanism of Saccharomyces cerevisiae, with thoce of Rickettsia prowazekii, suggest that only 5 sub units of the machinery have orthologous sequences from Rickettsia prowazekii. These 5 subunits are lo cated in the outer membrane and the matrix of mitochondria, while no subunit located in the inner mem brane and intermembrane space. Analysis of the Escherichia coli K

  3. 浙江省鼠形动物蜱源立克次体感染状况调查%A Cross-sectional study on tick-borne Rickettsiae infections among murine-like animals

    Institute of Scientific and Technical Information of China (English)

    柴程良; 陈恩富; 孙继民; 陆群英; 凌锋; 姜理平; 葛君华; 顾时平; 叶晓东; 刘社兰

    2014-01-01

    目的:了解浙江省不同类型地理环境中鼠形动物蜱源立克次体的感染状况。方法2009-2011年在安吉县、金东区和天台县用夹夜法捕获鼠形动物,进行分类鉴定、无菌采集肝脾标本,并采用巢式PCR方法检测无形体属与埃立克体属16SrRNA 以及立克次体属(包括斑疹伤寒群和斑点热群)与东方体属热休克蛋白基因groEL。结果3个调查点共捕获鼠形动物14种851头,社鼠(30.32%)、黑线姬鼠(18.80%)和青毛鼠(11.75%)为主要优势种,其中金东区、安吉县和天台县的优势鼠种分别为社鼠(39.20%)、青毛鼠(32.05%)和黑线姬鼠(59.57%)。562份肝脾标本中检出立克次体48份,阳性检出率为8.54%;其中无形体属占3.38%,斑疹伤寒群占1.78%,恙虫病东方体属占1.78%,埃立克体属占1.07%,斑点热群占0.53%。金东区和安吉县无形体属检出率较高为4.76%和4.27%,斑点热群仅在天台县检出。社鼠的立克次体阳性检出率最高为14.97%。同一鼠形动物可存在多种立克次体混合感染。结论浙江省不同类型地理环境鼠形动物中广泛存在立克次体感染,不同地理位?和不同鼠形动物的蜱源立克次体检出率不同。%Objective Toinvestigatethestatusoftick-borneRickettsiaeinfectionsamongmurine-likeanimalsin differentareasofZhejiangprovince.Methods Liverandspleensamplesofmurine-likeanimalscapturedthroughnight trapping method were collected from Anji,Jinhua and Tiantai County according to their geographic locations and historical detection of Rickettsiae .Nest-PCR tests were used to determine the presence of the 16S rRNA genes of Anaplasma and Ehrlichia ,and the heat shock protein genes (groEL)of Rickettsiae (including typhus and spotted fever group)and Orientiainthesesamples.Results Atotalof851murine-likeanimalsbelongingto14specieswerecaptured.The predominant species were Rattus confucianus (30

  4. Hierarchical population model with a carrying capacity distribution

    CERN Document Server

    Indekeu, J O

    2002-01-01

    A time- and space-discrete model for the growth of a rapidly saturating local biological population $N(x,t)$ is derived from a hierarchical random deposition process previously studied in statistical physics. Two biologically relevant parameters, the probabilities of birth, $B$, and of death, $D$, determine the carrying capacity $K$. Due to the randomness the population depends strongly on position, $x$, and there is a distribution of carrying capacities, $\\Pi (K)$. This distribution has self-similar character owing to the imposed hierarchy. The most probable carrying capacity and its probability are studied as a function of $B$ and $D$. The effective growth rate decreases with time, roughly as in a Verhulst process. The model is possibly applicable, for example, to bacteria forming a "towering pillar" biofilm. The bacteria divide on randomly distributed nutrient-rich regions and are exposed to random local bactericidal agent (antibiotic spray). A gradual overall temperature change away from optimal growth co...

  5. Boundary slippage for generating hydrodynamic load-carrying capacity

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-bin

    2008-01-01

    Boundary slippage is used to generate the load-carrying capacity of the hydrodynamic contact between two parallel plane surfaces.In the fluid inlet zone,the fluidcontact interfacial shear strength on a stationary surface is set at low to generate boundary slippage there,while in the fluid outlet zone the fluid-contact interfacial shear strength on the stationary surface is set at high enough to prevent the occurrence of boundary slippage.The fluid-contact interfacial shear strength on the entire moving surface is set at high enough to prevent boundary slippage on the moving surface.These hydrodynamic contact configurations are analyzed to generate the pronounced load-carrying capacity.The optimum ratio of the outlet zone width to the inlet zone width for the maximum load-carrying capacity of the whole contact is found to be 0.5.

  6. A portable virtual machine target for proof-carrying code

    DEFF Research Database (Denmark)

    Franz, Michael; Chandra, Deepak; Gal, Andreas;

    2005-01-01

    Virtual Machines (VMs) and Proof-Carrying Code (PCC) are two techniques that have been used independently to provide safety for (mobile) code. Existing virtual machines, such as the Java VM, have several drawbacks: First, the effort required for safety verification is considerable. Second and more...... subtly, the need to provide such verification by the code consumer inhibits the amount of optimization that can be performed by the code producer. This in turn makes justin-time compilation surprisingly expensive. Proof-Carrying Code, on the other hand, has its own set of limitations, among which...

  7. Description of Model Tests Carried Out by Aalborg University

    DEFF Research Database (Denmark)

    Frigaard, Peter; Schlütter, F.; Andersen, H.

    1996-01-01

    As associated partner, Aalborg University (AU) have participated in different aspects of "the Zeebrugge project". AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects.......As associated partner, Aalborg University (AU) have participated in different aspects of "the Zeebrugge project". AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects....

  8. Evaluation of carrying capacity and territorial environmental sustainability

    Directory of Open Access Journals (Sweden)

    Giuseppe Ruggiero

    2012-09-01

    Full Text Available Land use has a great impact on environmental quality, use of resources, state of ecosystems and socio-economic development. Land use can be considered sustainable if the environmental pressures of human activities do not exceed the ecological carrying capacity. A scientific knowledge of the capability of ecosystems to provide resources and absorb waste is a useful and innovative means of supporting territorial planning. This study examines the area of the Province of Bari to estimate the ecosystems’ carrying capacity, and compare it with the current environmental pressures exerted by human activities. The adapted methodology identified the environmentally sustainable level for one province.

  9. Design and Analysis of a High Speed Carry Select Adder

    OpenAIRE

    Simarpreet Singh Chawla; Swapnil Aggarwal; Anshika; Nidhi Goel

    2015-01-01

    An optimal high-speed and low-power VLSI architecture requires an efficient arithmetic processing unit that is optimized for speed and power consumption. Adders are one of the widely used in digital integrated circuit and system design.High speed adder is the necessary component in a data path, e.g. Microprocessors and a Digital signal processor. The present paper proposes a novel high-speed adder by combining the advantages of Carry Look Ahead Adder (CLAA) and Carry Select Adder (CSA), devis...

  10. Design and Analysis of a High Speed Carry Select Adder

    OpenAIRE

    Simarpreet Singh Chawla; Swapnil Aggarwal; Anshika; Nidhi Goel

    2015-01-01

    An optimal high-speed and low-power VLSI architecture requires an efficient arithmetic processing unit that is optimized for speed and power consumption. Adders are one of the widely used in digital integrated circuit and system design. High speed adder is the necessary component in a data path, e.g. Microprocessors and a Digital signal processor. The present paper proposes a novel high-speed adder by combining the advantages of Carry Look Ahead Adder (CLAA) and Carry Select Adder (CSA), devi...

  11. Molecular detection of Anaplasma platys, Ehrlichia canis, Hepatozoon canis and Rickettsia monacensis in dogs from Maio Island of Cape Verde archipelago.

    Science.gov (United States)

    Lauzi, Stefania; Maia, João P; Epis, Sara; Marcos, Ricardo; Pereira, Cristina; Luzzago, Camilla; Santos, Marta; Puente-Payo, Pablo; Giordano, Alessia; Pajoro, Massimo; Sironi, Giuseppe; Faustino, Augusto

    2016-07-01

    Tick-borne diseases are emerging worldwide and have an important zoonotic relevance. Dogs play an important role in the epidemiology of several zoonotic tick-borne pathogens acting as sentinels and/or reservoirs. This study focused on the molecular identification of tick-borne pathogens in blood samples of 153 autochthonous asymptomatic dogs in Maio Island, Cape Verde archipelago. Eighty-four (54.9%) dogs were positive for one or more pathogens. Fifty-five (35.9%) dogs were infected with Hepatozoon canis, 53 (34.6%) with Anaplasma platys, five (3.3%) with Ehrlichia canis and Rickettsia monacensis, an emerging human pathogen, was also identified in a single dog (0.7%). The former three pathogens cause important canine tick-borne diseases that are transmitted or potentially transmitted by Rhipicephalus sanguineus s.l., the only hard tick identified in Cape Verde. Furthermore, Wolbachia spp. was amplified from the blood of one dog. None of the dogs were positive for Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Midichloria mitochondrii, Bartonella spp., Babesia spp. or Theileria spp. Fifty-four (35.3%) animals showed single infections and 30 (19.6%) co-infections, with A. platys and H. canis co-infection being the most frequent (28 dogs, 18.3%). The frequency of E. canis infection was statistically different among age groups (P=0.017), being higher among dogs older than 4 years compared to younger dogs. Infection by A. platys was also statistically different among age groups (P=0.031), being higher in dogs younger than 2 years compared to older dogs. The statistical analyses showed no significant association of PCR positivity with gender or location. The frequency of tick-borne pathogens detected in dogs in Maio Island, including R. monacensis, highlights the need to improve diagnosis and control in order to prevent the risk of transmission of these pathogens among dogs and humans living in or travelling to this touristic island.

  12. Liver Necrosis and Lethal Systemic Inflammation in a Murine Model of Rickettsia typhi Infection: Role of Neutrophils, Macrophages and NK Cells

    Science.gov (United States)

    Papp, Stefanie; Moderzynski, Kristin; Rauch, Jessica; Heine, Liza; Kuehl, Svenja; Richardt, Ulricke; Mueller, Heidelinde; Fleischer, Bernhard; Osterloh, Anke

    2016-01-01

    Rickettsia (R.) typhi is the causative agent of endemic typhus, an emerging febrile disease that is associated with complications such as pneumonia, encephalitis and liver dysfunction. To elucidate how innate immune mechanisms contribute to defense and pathology we here analyzed R. typhi infection of CB17 SCID mice that are congenic to BALB/c mice but lack adaptive immunity. CB17 SCID mice succumbed to R. typhi infection within 21 days and showed high bacterial load in spleen, brain, lung, and liver. Most evident pathological changes in R. typhi-infected CB17 SCID mice were massive liver necrosis and splenomegaly due to the disproportionate accumulation of neutrophils and macrophages (MΦ). Both neutrophils and MΦ infiltrated the liver and harbored R. typhi. Both cell populations expressed iNOS and produced reactive oxygen species (ROS) and, thus, exhibited an inflammatory and bactericidal phenotype. Surprisingly, depletion of neutrophils completely prevented liver necrosis but neither altered bacterial load nor protected CB17 SCID mice from death. Furthermore, the absence of neutrophils had no impact on the overwhelming systemic inflammatory response in these mice. This response was predominantly driven by activated MΦ and NK cells both of which expressed IFNγ and is considered as the reason of death. Finally, we observed that iNOS expression by MΦ and neutrophils did not correlate with R. typhi uptake in vivo. Moreover, we demonstrate that MΦ hardly respond to R. typhi in vitro. These findings indicate that R. typhi enters MΦ and also neutrophils unrecognized and that activation of these cells is mediated by other mechanisms in the context of tissue damage in vivo. PMID:27548618

  13. Ticks Carrying Lyme Disease Confirmed in Eastern National Parks

    Science.gov (United States)

    ... html Ticks Carrying Lyme Disease Confirmed in Eastern National Parks U.S. National Park Service and CDC advise using insect repellents on ... Planning a hiking trip in an eastern U.S. national park? Better pack tick repellent -- a new study found ...

  14. Wakes in Dilatonic Current-Carrying Cosmic Strings

    CERN Document Server

    Oliveira, A L N

    2003-01-01

    In this work, we present the gravitational field generated by a cosmic string carrying a timelike current in the scalar-tensor gravities. The mechanism of formation and evolution of wakes is fully investigated in this framework. We show that the inclusion of electromagnetic properties for the string induces logarithmic divergences in the accretion problem.

  15. Pyrosequencing reveals bacteria carried in different wind eroded sediments

    Science.gov (United States)

    Little is known about the microbial communities carried in wind-eroded sediments from various soil types and land management systems. A novel technique, pyrosequencing, promises to expand our understanding of the vast microbial diversity of soils and eroded sediments as it can sequence between 10-10...

  16. Maze Busters: Carrie Miyoshi Macfarlane & Kathleen Sheehan--Harvard University

    Science.gov (United States)

    Library Journal, 2004

    2004-01-01

    Even if one is equipped with an MLS, the 11 libraries that comprise the Harvard College Library can be pretty daunting. That is why Carrie Miyoshi Macfarlane and Kathleen Sheehan created Threading the Maze. The online publication is presented to students in expository writing, the one course all undergraduates must take. "This highly effective…

  17. Connection and Commitment: The Career of Carrie Billy

    Science.gov (United States)

    Peterson, Richard

    2015-01-01

    Carrie Billy, a member of the Navajo Nation and CEO and president of the American Indian Higher Education Consortium (AIHEC), attributes one of the country's oldest youth organizations, Girl Scouts, for opening her mind to the possibility of creating change for countless citizens. She is a trained attorney and has made it her life work to advocate…

  18. "The Bell Curve" and Carrie Buck: Eugenics Revisited.

    Science.gov (United States)

    Smith, J. David

    1995-01-01

    The 1994 publication of "The Bell Curve" by R. Herrnstein and C. Murray is compared to other examples of eugenic principles, including the sterilization of "feebleminded" Carrie Buck, family degeneracy studies focusing on lower class Caucasian families, and other works that view the poorest and least educated members of society…

  19. Debris-carrying camouflage among diverse lineages of Cretaceous insects

    Science.gov (United States)

    Wang, Bo; Xia, Fangyuan; Engel, Michael S.; Perrichot, Vincent; Shi, Gongle; Zhang, Haichun; Chen, Jun; Jarzembowski, Edmund A.; Wappler, Torsten; Rust, Jes

    2016-01-01

    Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore, little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects. PMID:27386568

  20. Cultural Carrying Capacity: A Biological Approach to Human Problems.

    Science.gov (United States)

    Hardin, Garrett

    1992-01-01

    In discussing the human and cultural implications of scientific discoveries and knowledge, the biological concept of carrying capacity is explored. Maintaining that human beings are truly animals answering to principles that govern all animals, the author addresses the need for human populations to work within the context of culture and carrying…

  1. Cognitive Load in Voice Therapy Carry-Over Exercises

    Science.gov (United States)

    Iwarsson, Jenny; Morris, David Jackson; Balling, Laura Winther

    2017-01-01

    Purpose: The cognitive load generated by online speech production may vary with the nature of the speech task. This article examines 3 speech tasks used in voice therapy carry-over exercises, in which a patient is required to adopt and automatize new voice behaviors, ultimately in daily spontaneous communication. Method: Twelve subjects produced…

  2. Nanoparticles carry chemotherapy drug deeper into solid tumors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ CAS researchers have developed a new drug delivery method using nano-sized molecules to carry the chemotherapy drug doxorubicin to tumors, improving the effectiveness of the drug in mice and increasing their survival time. Their work has been reported online June 26 in the Journal of the National Cancer Institute.

  3. Arrangement for carrying out and studying chemical reactions

    NARCIS (Netherlands)

    Langeveld, A.D.; Makkee, M.; Moulijn, J.A.

    1993-01-01

    Abstract of NL 9102029 (A) Described is an arrangement for carrying out TAP experiments. Such an arrangement comprises a reaction chamber in which a very short-lived beam of molecules is directed at a target to produce a short-lived beam of intermediate-product molecules, and a vacuum chamber wher

  4. 44 CFR 332.3 - Carrying out voluntary agreements.

    Science.gov (United States)

    2010-10-01

    ... advance, each meeting of the participants in the agreement held to discuss problems, determine policies... § 332.5 of this part. A person attending a meeting under this section may present oral or written data... communications among themselves or with any other member of their industry, related to the carrying out of...

  5. Serosurvey of Rickettsia spp. in dogs and humans from an endemic area for Brazilian spotted fever in the State of São Paulo, Brazil Sorologia para Rickettsia spp. em cães e humanos de uma área endêmica para febre maculosa brasileira no Estado de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Adriano Pinter

    2008-02-01

    Full Text Available The present study provides a rickettsial serosurvey in 25 dogs and 35 humans in an endemic area for Brazilian spotted fever in the State of São Paulo, where the tick Amblyomma aureolatum is the main vector. Testing canine and human sera by indirect immunofluorescence against four Rickettsia antigens (R. rickettsii, R. parkeri, R. felis and R. bellii showed that 16 (64% of canine sera and 1 (2.8% of human sera reacted to at least one of these rickettsial antigens with titers ³ 64. Seven canine sera and the single reactive human serum showed titers to R. rickettsii at least four times those of any of the other three antigens. The antibody titers in these 7 animals and 1 human were attributed to stimulation by R. rickettsii infection. No positive canine or human serum was attributed to stimulation by R. parkeri, R. felis, or R. bellii. Our serological results showed that dogs are important sentinels for the presence of R. rickettsii in areas where the tick A. aureolatum is the main vector of Brazilian spotted fever.Este estudo avaliou a ocorrência de anticorpos anti-Rickettsia em 25 cães e 35 humanos, em uma área endêmica para a febre maculosa brasileira no Estado de São Paulo, onde o principal vetor é o carrapato Amblyomma aureolatum. Soros dos cães e humanos foram testados pela técnica de imunofluorescência indireta contra quatro antígenos de riquétsias (R. rickettsii, R. parkeri, R. felis, R. bellii, mostrando que soros de 16 (64% cães e 1 (2,8% humano reagiram com títulos ³ 64 para pelo menos um dos antígenos de riquétsias. Sete soros caninos e o único soro humano reativo demonstraram títulos para R. rickettsii no mínimo quatro vezes maior do que aqueles para os outros antígenos de riquétsias. Os títulos de anticorpos nesses cães e um humano foram considerados homólogos a R. rickettsii, enquanto que nenhum soro de cão ou humano foi considerado reativamente homólogo para R. parkeri, R. felis ou R. bellii. Os

  6. Efficient Design of Ripple Carry Adder and Carry Skip Adder with Low Quantum Cost and Low Power Consumption

    Directory of Open Access Journals (Sweden)

    Nidhi

    2014-07-01

    Full Text Available The addition of two binary numbers is the important and most frequently used arithmetic process on microprocessors, digital signal processors (DSP, and data-processing application-specific integrated circuits (ASIC. Therefore, binary adders are critical structure blocks in very large-scale integrated (VLSI circuits. Their effective application is not trivial because a costly carry spread operation involving all operand bits has to be achieved. Many different circuit constructions for binary addition have been planned over the last decades, covering a wide range of presentation characteristics. In today era, reversibility has become essential part of digital world to make digital circuits more efficient. In this paper, we have proposed a new method to reduce quantum cost for ripple carry adder and carry skip adder. The results are simulated in Xilinx by using VHDL language.

  7. Molecular evidence of vector-borne pathogens in dogs and cats and their ectoparasites in Algiers, Algeria.

    Science.gov (United States)

    Bessas, Amina; Leulmi, Hamza; Bitam, Idir; Zaidi, Sara; Ait-Oudhia, Khatima; Raoult, Didier; Parola, Philippe

    2016-04-01

    In Algeria, only limited information is currently available on the prevalence of emergent canine and feline vector-borne diseases. The aim of the present work was to detect by qPCR vector-associated bacteria in stray dogs and cats and their ectoparasites from Algiers. 18/117 (15.38%) dogs and 2/107 (1.87%) cats were positive for at least one vector-borne agent. Coxiella burnetii and Bartonella henselae were identified in 1/117 (0.85%) dog individually. Ehrlichia canis DNA was detected in 17/117 (14.52%) dogs. 1/107 (0.93%) cat was positive to C. burnetii and another 1/107 (0.93%) to B. henselae. DNA of Rickettsia massiliae, Rickettsia conorii and E. canis was detected in Rhipicephalus sanguineus. Cat fleas were infected with Rickettsia felis, B. henselae and Bartonella clarridgeiae. B. vinsonii subsp. berkhoffii was identified in Xenopsylla cheopis collected from dogs. The findings of this study indicate that dogs and cats from Algeria are exposed to multiple tick and flea-borne pathogens.

  8. Ixodid fauna and zoonotic agents in ticks from dogs: first report of Rickettsia rickettsii in Rhipicephalus sanguineus in the state of Mato Grosso do Sul, mid-western Brazil.

    Science.gov (United States)

    de Almeida, Robson Ferreira Cavalcante; Garcia, Marcos Valério; Cunha, Rodrigo Casquero; Matias, Jaqueline; e Silva, Elaine Araújo; de Fatima Cepa Matos, Maria; Andreotti, Renato

    2013-05-01

    Ticks from 148 dogs from the urban area of the municipality of Campo Grande, state of Mato Grosso do Sul, Brazil, were collected, classified and analyzed using polymerase chain reaction (PCR) for the identification of Rickettsia spp., Trypanosoma cruzi and Leishmania spp. A total of 2015 ticks were collected. The species Rhipicephalus sanguineus (98.9 %) and Amblyomma cajennense (1.1 %) were identified. Molecular analysis revealed that no tick samples were infected by T. cruzi. Regarding Leishmania spp., tick samples from 36 dogs spread across all regions of the municipality were positive for L. chagasi. One tick sample was positive for Rickettsia spp. (gltA gene) in the PCR reaction. This sample was submitted to further PCR based on the ompA gene and the amplicon was sequenced. Identity of 100 % was found with homologous sequences of R. rickettsii available in GenBank. This paper is the first to report the natural infection of R. sanguineus by R. rickettsii in the municipality of Campo Grande, state of Mato Grosso do Sul, mid-western Brazil.

  9. Molecular characteristics of emerging spotted fever group Rickettsiae and Anaplasma phagocytophilum in Hebei province, China%河北新发斑点热及人粒细胞无形体病实验室调查分析

    Institute of Scientific and Technical Information of China (English)

    孙印旗; 王勇; 姜霞; 姚娜; 钱振宇; 刘晓丽; 陈创夫; 张丽娟

    2015-01-01

    目的:对河北省新发蜱传斑点热群立克次体及人粒细胞无形体进行分子流行病学特征分析。方法对2009-2012年在河北省辛集、迁安及定州市收集的101份临床可疑立克次体病病例急性期血液DNA样本,采用2套巢氏PCR法分别扩增斑点热群立克次体热休克蛋白基因(groEL)和人粒细胞无形体16S rRNA基因并测序,序列采用NCBI网站进行Blast分析后,选择不同地区、不同宿主来源相应基因,使用DNAStar MegAlign同源分析。结果10.9%(11/101)的病例groEL扩增阳性,同源分析当地斑点热群立克次体groEL基因分为2个序列型,尽管有限片段无法区别立克次体种,但PCR阳性病例血清与我国常见黑龙江立克次体、西伯利亚立克次体、海南斑点热群立克次体及蚤传斑点热立克次体无抗原抗体反应,提示可能为新发斑点热。人粒细胞无形体16S rRNA基因扩增阳性率为8.9%(9/101),且病例急性期血清人粒细胞无形体IgM抗体全部阳性,其中3例急性期与恢复期血清发生IgG抗体转换。16S rRNA基因测序成功的9个序列(341 bp)100%同源,并且与该地区无形体病例分离株CZ-HGA-2100%同源。结论河北地区可能存在新发蜱传人粒细胞无形体病例及新发斑点热。加强立克次体实验室诊断及鉴别诊断、进一步开展病原学、相关媒介及宿主流行病学调查均具有重要的临床及公共卫生意义。%Objective To better understand the molecular epidemiological characteristics of emerging spotted fever group Rickettsiae and Anaplasma phagocytophilum identified in Hebei province. Methods One hundred and one clinical probable cases of typhus were collected from Xinji city, Qianan city and Dingzhou city, Hebei province during 2009-2012 and 101 acute stage and 17 convalescence blood samples were collected. Sera separated from blood were used for detecting the IgM and IgG antibodies against

  10. Different Ways of Carrying Bags in Mental Retarded Students

    Directory of Open Access Journals (Sweden)

    Saideh-Sadat Mortazavi

    2012-10-01

    Full Text Available School as an educational and social center is linked with various aspects of child’s growth. The impact of objects, tools, and lifestyle on the development of human performance is not hidden from anyone [1].Tasell Lauri, the head of Cairo Praktive in Australia, in a paper warned parents about bags as a tool that students carry every day, and he is believes that many spinal disorders in adults is caused by childhood trauma. Studies on children and patients with special needs and such as myelomenangocele, cerebral palsy, and neurofibromatosis precisely show abnormal growth of spinal disorders, muscle imbalance, wrong posture [2]. Carrying stationery in an inappropriate tool can cause irreversible effects.

  11. Carrying guns in public: legal and public health implications.

    Science.gov (United States)

    Vernick, Jon S

    2013-03-01

    In District of Columbia v. Heller, the U.S. Supreme Court ruled that the Second Amendment protects an individual's right to own handguns in the home for protection, invalidating a Washington, D.C. law banning most handgun possession. The Heller decision, however, provided lower courts with little guidance regarding how to judge the constitutionality of gun laws other than handgun bans. Nevertheless, lower courts have upheld the vast majority of federal, state, and local gun laws challenged since Heller. One area in which some lower courts have disagreed has been the constitutionality of laws regulating the ability to carry firearms in public. This issue may be the next to be addressed by the Supreme Court under its evolving Second Amendment jurisprudence. Courts should carefully consider the negative public health and safety implications of gun carrying in public as they weigh the constitutionality of these laws.

  12. High Speed Boosted Cmos Differential Logic for Ripple Carry Adders

    Directory of Open Access Journals (Sweden)

    Meenu Roy,

    2014-01-01

    Full Text Available This paper describes a high speed boosted CMOS differential logic which is applicable in Ripple Carry Adders. The proposed logic operating with supply voltage approaching the MOS threshold voltage. The logic style improves switching speed by boosting the gate-source voltage of transistors along timing critical signal path. It allows a single boosting circuit to be shared by complementary outputs as a result the area overhead also minimizes. As compared to the conventional logic gates the EDP (energy delay product is improved. The test sets of logic gates and adders where designed in tsmc0.18μm of Mentor Graphics EDA tool. The experimental result for Ripple Carry Adders using the proposed logic style revealed that the addition time is reduced as compared with the conventional CMOS circuits.

  13. Variable Block Carry Skip Logic using Reversible Gates

    CERN Document Server

    Islam, Md Rafiqul; Karim, Muhammad Rezaul; Mahmud, Abdullah Al; Babu, Hafiz Md Hasan

    2010-01-01

    Reversible circuits have applications in digital signal processing, computer graphics, quantum computation and cryptography. In this paper, a generalized k*k reversible gate family is proposed and a 3*3 gate of the family is discussed. Inverter, AND, OR, NAND, NOR, and EXOR gates can be realized by this gate. Implementation of a full-adder circuit using two such 3*3 gates is given. This full-adder circuit contains only two reversible gates and produces no extra garbage outputs. The proposed full-adder circuit is efficient in terms of gate count, garbage outputs and quantum cost. A 4-bit carry skip adder is designed using this full-adder circuit and a variable block carry skip adder is discussed. Necessary equations required to evaluate these adder are presented.

  14. A novel reversible carry-selected adder with low latency

    Science.gov (United States)

    Li, Ming-Cui; Zhou, Ri-Gui

    2016-07-01

    Reversible logic is getting more and more attention in quantum computing, optical computing, nanotechnology and low-power complementary metal oxide semiconductor designs since reversible circuits do not loose information during computation and have only small energy dissipation. In this paper, a novel carry-selected reversible adder is proposed primarily optimised for low latency. A 4-bit reversible full adder with two kinds of outputs, minimum delay and optimal quantum cost is presented as the building block for ?-bit reversible adder. Three new reversible gates NPG (new Peres gate), TEPG (triple extension of Peres gate) and RMUX21 (reversible 2-to-1 multiplexer) are proposed and utilised to design efficient adder units. The secondary carry propagation chain is carefully designed to reduce the time consumption. The novelty of the proposed design is the consideration of low latency. The comparative study shows that the proposed adder achieves the improvement from 61.46% to 95.29% in delay over the existing designs.

  15. A C-Testable Multiple-Block Carry Select Adder

    Science.gov (United States)

    Kito, Nobutaka; Fujii, Shinichi; Takagi, Naofumi

    We propose a C-testable multiple-block carry select adder with respect to the cell fault model. Full adders and 2: 1 multiplexers are considered as cells. By an additional external input, we obtain a C-testable carry select adder. We only modify the least significant position of each block. The adder is testable with a test set consisting of 16 patterns regardless of the size of each block and the number of blocks. This is the minimum test set for the adder. We show two gate-level implementations of the adder which are testable with a test set of 9 patterns and 7 patterns respectively, with respect to the single stuck-at fault model.

  16. Filaggrin compound heterozygous patients carry mutations in trans position

    DEFF Research Database (Denmark)

    Carlsen, Berit C; Meldgaard, Michael; Johansen, Jeanne D;

    2013-01-01

    More than 40 null mutations in the filaggrin (FLG) gene are described. It is therefore possible to find two different null mutations in one individual (compound heterozygosity). It has been generally perceived that homozygous and compound heterozygous individuals were genotypically comparable; ho...... compound heterozygous individuals were found to carry the two mutations in trans position. FLG null mutation compound heterozygous individuals can be considered functionally equivalent to FLG null mutation homozygosity for any of the two mutations....

  17. Modeling the Flexural Carrying Capacity of Corroded RC Beam

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-hui; LIU Xi-la

    2008-01-01

    Considering the change of bond strength between corroded steel and concrete, flexural carrying ca-pacity of corroded reinforced concrete (RC) beam was calculated. On the basis of the condition of equilibriumof forces and compatibility of deformations for the whole beam, a model for the prediction of flexural carryingcapacity of the corroded RC beam was proposed. Comparison of the model's predictions with the experimentalresults published in the literature shows the practicality of the proposed method.

  18. Self-timed Manchester chain carry propagate adder

    OpenAIRE

    Escribà, J; Carrasco, Juan A.

    1996-01-01

    The authors present a self-timed adder that uses two Manchester chains to propagate carries in a two-rail code. With the inclusion of buffers in the chains, the adder meets the timing conditions typical of an asynchronous design based in the ‘bundled-data, bounded-delay’ model and is signifcantly faster than self-timed adders with restoring logic and similar complexity.

  19. High Speed Carry Select Adder for ALU Blocks

    Directory of Open Access Journals (Sweden)

    J.Rama Krishna Reddy

    2013-06-01

    Full Text Available The regular SQRT CSLA consists of two RCA blocks with carry input as 0 and 1.The Final sum will be selected from multiplexers (Mux by the carry out generated by the pervious block. This paper, proposes an area and delay efficient carry select adder with logical reduction of excess redundant hardware. In the proposed architecture, we had implemented the RCA with carry input as 1, only with Mux, Or gate and And gate. For 16-bit regular SQRT CSLA there is a reduction of basic logic gates from 434 to 323.The delay is reduced by replacing Full-adder with half-adder in first bit of every RCA in theproposed architecture. This will reduces the number of Iterations required to get the final sum. The proposed architecture shows that there is reduction of area and delay. Based on this architecture, wedesigned 4-bit,8-bit,16-bit and 32-bit Square-root CSLA (SQRT CSLA and compared with the regular SQRT CSLA. In this work, we evaluated the performance of the proposed design in 90-ηm CMOS Technology in Cadence Tools. The result analysis shows that, the proposed SQRT CSLA of 4-bit, 8-bit 16- bit and 32-bit has a reduction of 31.74%, 30.13%, 21.92% and 21.76 % respectively compared with regular SQRT CSLA in area. The delay of Proposed SQRT CSLA of 4-bit,8-bit 16-bit and 32-bit are reduce by 27.47%, 17.23%, 14.32% and 11.63% respectively.

  20. Targeted drug-carrying bacteriophages as antibacterial nanomedicines.

    Science.gov (United States)

    Yacoby, Iftach; Bar, Hagit; Benhar, Itai

    2007-06-01

    While the resistance of bacteria to traditional antibiotics is a major public health concern, the use of extremely potent antibacterial agents is limited by their lack of selectivity. As in cancer therapy, antibacterial targeted therapy could provide an opportunity to reintroduce toxic substances to the antibacterial arsenal. A desirable targeted antibacterial agent should combine binding specificity, a large drug payload per binding event, and a programmed drug release mechanism. Recently, we presented a novel application of filamentous bacteriophages as targeted drug carriers that could partially inhibit the growth of Staphylococcus aureus bacteria. This partial success was due to limitations of drug-loading capacity that resulted from the hydrophobicity of the drug. Here we present a novel drug conjugation chemistry which is based on connecting hydrophobic drugs to the phage via aminoglycoside antibiotics that serve as solubility-enhancing branched linkers. This new formulation allowed a significantly larger drug-carrying capacity of the phages, resulting in a drastic improvement in their performance as targeted drug-carrying nanoparticles. As an example for a potential systemic use for potent agents that are limited for topical use, we present antibody-targeted phage nanoparticles that carry a large payload of the hemolytic antibiotic chloramphenicol connected through the aminoglycoside neomycin. We demonstrate complete growth inhibition toward the pathogens Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli with an improvement in potency by a factor of approximately 20,000 compared to the free drug.

  1. Low Power 256-bit Modified Carry Select Adder

    Directory of Open Access Journals (Sweden)

    P. Ramani

    2014-09-01

    Full Text Available Carry Select Adder (CSLA is one of the high speed adders used in many computational systems to perform fast arithmetic operations. When compared to earlier Ripple Carry Adder and Carry Look Ahead Adder, Regular CSLA (R-CSLA is observed to provide optimized results in terms of area. This study proposes an efficient method which replaces the RCA using BEC. The modified CSLA architecture has been developed using gate-level modification to significantly reduce the delay and power of the CSLA. Based on this modification 8-, 16-, 32-, 64- and 128-bit Square-Root CSLA (SQRT CSLA architecture have been developed and compared with the regular SQRT CSLA architecture. The proposed design for 256-bit has reduced power and delay as compared with the regular SQRT CSLA. Designs were developed using structural Verilog module and synthesized using Xilinx ISE simulator and the implementation is done in cadence RTL compiler using 0.18 µm technology. For 256-bit addition in this study, it is proposed to simple gate level modification which significantly reduces the power by 19.4% when compared with R-CSLA. The result analysis shows that the proposed architecture achieves two folded advantages in terms of delay and power.

  2. Anticorpos anti-rickettsias do grupo da febre maculosa em equídeos e caninos no norte do Estado do Paraná, Brasil Anti rickettsia-antibody for spotted fever group in horses and dogs in the North of Paraná Stated, Brazil

    Directory of Open Access Journals (Sweden)

    F.H. Otomura

    2010-06-01

    Full Text Available The Brazilian Spotted Fever (BSF is a zoonosis that can be fatal if not trteated. As there are few studies of the BSF in the Paraná State, the occurrence of BSF was serologically investigated in dogs and horses by indirect immunofluorescence assay (IFA, in the North of that State, in animals that are regarded as sentinels for BSF. A total of 241 samples of sera of equine, four of asinine, and 29 of dogs were collected in nine farms of three municipalities in the North of Paraná: Arapongas, Douradina, and Umuarama. From fifteen samples of equine serum with positive titres for RIFI, eight (53.3 % had titre of 64 against R. rickettsii, two (13.3 % 128 against R. rickettsii, and five (33.3 % were reactants for R. parkeri and R. rickettsii, with titres ranging from 64 to 2048, and 128 to 1024, respectively. The results showed that domestic animals, sentinels for BSF, are under low exposition to ticks infected with spotted fever group Rickettsia, indicating low risk of human infection by these agents in the studied area.

  3. [THE HIGHLY EFFECTIVE DETECTION OF DNA RICKETTSIA USING TECHNIQUE OF POLYMERASE CHAIN REACTION IN REAL-TIME].

    Science.gov (United States)

    Kartashov, M Yu; Mikryukova, T P; Ternovoi, V A; Moskvitina, N S; Loktev, V B

    2015-12-01

    The article considers development of highly effective technique of detection of genetic material of ricketsia based on polymerase chain reaction in real-time using original primers to the most conservative sites of gene of citrate synthase (gItA). The analytical sensitivity of the developed polymerase chain reaction in real-time test permits to detect from 80 genome equivalents in analyzed sample during three hours. The high specificity of test-system is substantiated by detection of nucleotide sequences of amplificated fragments of gene gltA. The approbation ofthe polymerase chain reaction in real-time test is carried out on collection of 310 ticks of species I. persulcatus, I. pavlovskyi, D. reticulatus. It is demonstrated that the developed alternate ofprimers and probe permits with high degree of sensitivity and specifcity to detect DNA of different species of ricketsia widespread on territory of Russia (R. sibirica, R. raoultii, R. helvetica, R. tarasevichiae). The proposed polymerase chain reaction in real-time test can be appliedfor isolation of fragment of gene gltA with purpose for detecting nucleotide sequence and subsequent genetic typing of ricketsia. The application ofthe proposed technique can facilitate task of monitoring hot spots of ricketsiosis.

  4. Efficient Design of Ripple Carry Adder and Carry Skip Adder with Low Quantum Cost and Low Power Consumption

    OpenAIRE

    Nidhi; Gurinderpal Singh

    2014-01-01

    The addition of two binary numbers is the important and most frequently used arithmetic process on microprocessors, digital signal processors (DSP), and data-processing application-specific integrated circuits (ASIC). Therefore, binary adders are critical structure blocks in very large-scale integrated (VLSI) circuits. Their effective application is not trivial because a costly carry spread operation involving all operand bits has to be achieved. Many different circuit constru...

  5. [Simple locomotion and during load carrying in pregnant women].

    Science.gov (United States)

    Golomer, E; Ducher, D; Arfi, G S; Sud, R

    1991-01-01

    There have been few studies of the way women walk in pregnancy, though some of the causes of low back ache of which they complain have only been partially worked out. This is why this study has been carried out on ten women between the third and eighth month of pregnancy. The speed at which they walk and the parameters of the gait as well as the localization of the centre of gravity when keeping upright have been measured in these pregnant women as well as in twenty control women of the same age. The results show that the speed at which they walk whether with or without carrying a weight usually is identical at the beginning and the end of pregnancy. When walking normally the size of the steps taken are no larger in pregnant women than in the control patients (p less than 0.05). Though the results are not statistically significant the rhythm of the steps is faster as well as their being a reduction in the length of the steps between the third and eighth month of pregnancy. When carrying a weight the length of the steps does not change greatly with pregnancy (p less than 0.05) and it would seem therefore to be a good way of assessing the changes that locomotion undergoes in pregnancy. The fact that women do not walk faster or slower can give evidence that they adapt to the change in posture that happens in pregnancy and they make the best possible biomechanical use of the parameters of walking in order to economise total energy output of the organism.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Cognitive Load in Voice Therapy Carry-Over Exercises

    DEFF Research Database (Denmark)

    Iwarsson, Jenny; Morris, David Jackson; Balling, Laura Winther

    2017-01-01

    Purpose The cognitive load generated by online speech production may vary with the nature of the speech task. This article examines 3 speech tasks used in voice therapy carry-over exercises, in which a patient is required to adopt and automatize new voice behaviors, ultimately in daily spontaneous...... communication. Method Twelve subjects produced speech in 3 conditions: rote speech (weekdays), sentences in a set form, and semispontaneous speech. Subjects simultaneously performed a secondary visual discrimination task for which response times were measured. On completion of each speech task, subjects rated...

  7. Behavioral Indicators of Legal and Illegal Gun Carrying

    Science.gov (United States)

    2015-05-01

    access to the gun by simply reaching under the shirt or lifting up the shirt. Depending on the size of the gun and how it is secured, it will sometimes...person runs, the more the gun will wiggle. Depending upon the type of clothes a person is wearing and the size of the gun, there is likely to be a...the mass and size of the weapon and how it is carried. Second, those related to the situational and environmental awareness of the individual

  8. The information carrying capacity of a cosmological constant

    CERN Document Server

    Simidzija, Petar

    2016-01-01

    We analyze the exchange of information in different cosmological backgrounds when sender and receiver are timelike separated and communicate through massless fields (without the exchange of light-signals). Remarkably, we show that the dominance of a cosmological constant makes the amount of recoverable information imprinted in the field by the sender extremely resilient: it does not decay in time or with the spatial separation of sender and receiver, and it actually increases with the rate of expansion of the Universe. This is in stark contrast with the information carried by conventional light-signals and with previous results on timelike communication through massless fields in matter dominated cosmologies.

  9. The carry-over effect does not influence football results.

    OpenAIRE

    Goossens, Dries; Spieksma, Frederik

    2012-01-01

    In a round robin tournament, it is often believed that each team has an effect on its opponent, which carries over to the next game of that opponent. Indeed, if team A plays against team B, and subsequently against team C, A’s performance against C may have been affected by B, and we say that team C receives a carryover effect from B. For instance, if team B is a very strong team, then team A could be exhausted and discouraged after this game, which could benefit its next opponent, team C. Cl...

  10. Design and Verification of Advanced Carry Select Adder

    Directory of Open Access Journals (Sweden)

    Guru Dixit Chepuri

    2014-05-01

    Full Text Available Design ofareaefficient data pathlogicsystems formsthelargestareasofresearch inVLSIsystem design.Indigital adders, thespeed of addition islimitedbythetimerequired totransmit a carrythroughtheadder.CarrySelectAdder (CSA isoneofthefastestadders usedinmanydata-processingprocessorstoperform fastarithmetic functions. Fromthestructure oftheCSA,itisclear thatthereisscopeforreducing thearea and powerintheCSA. This work usesasimpleandefficient gate-level modification todrasticallyreducetheareaandpower oftheCSA.Basedonthismodification 16,32,64 and128-bitsquare-root CSA(SQRT CSA architectureshavebeendevelopedandcomparedwith theregularSQRTCSAarchitecture. Theproposed designhasreducedarea and powerascompared withtheregular SQRTCSA.Thisworkestimates theperformanceof theproposed designsintermsofpower,areaand isimplementedusingXilinxISE and synthesized using cadence in 90nm technology.

  11. Optimal Final Carry Propagate Adder Design for Parallel Multipliers

    CERN Document Server

    B., Ramkumar

    2011-01-01

    Based on the ASIC layout level simulation of 7 types of adder structures each of four different sizes, i.e. a total of 28 adders, we propose expressions for the width of each of the three regions of the final Carry Propagate Adder (CPA) to be used in parallel multipliers. We also propose the types of adders to be used in each region that would lead to the optimal performance of the hybrid final adders in parallel multipliers. This work evaluates the complete performance of the analyzed designs in terms of delay, area, power through custom design and layout in 0.18 um CMOS process technology.

  12. Reflection of Naturalism and Darwinism in Dreiser' s Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    王静

    2009-01-01

    Naturalism is a significant school of literature in American literary history. This thesis mainly reviews the background, development, and characteristic of the realism and naturalism literature, and states the significant person in Naturalism literature-Dreiser and his. important literary position and analyzes the reflection of naturalism and Darwinism in Sister Carrie. Through the analysis of determinism, desire, ethics and detail description, a conclusion is made: the factors affecting the novel' s writing not only include the author' s own experiences but also the main social ideology in his living years.

  13. Studies on rickettsia-like organism (RLO)disease of tropical marine pearl oyster--Epidemiological investigation of RLO disease in larvae populations of maricultured Pinctada maxima

    Institute of Scientific and Technical Information of China (English)

    Wu Xinzhong; Li Dengfeng; Pan Jinpei

    2001-01-01

    The epidemiological investigations on the disease and death in mature eggs, embryonic developmental periods and larvae populations [ including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D- shaped phase larvae (24 h), early umbo phase larvae, umbo phase larvae, post umbo phase larvae and eyespot phase larvae] in the Luhuitou Pearl Oyster Mariculture Farm of Sanya City,Hainan Province in April 1995 showed that there were two peaks of mortality rates which occurred in early umbo phase or umbo phase and post umbo phase (Figs 3 ~ 5 and Table 1 ) respectively from preembryonic developmental periods to larvae phases. It indicated that the onset and death of Pinctada maxima larvae populations followed a pattern of outbreak. Between the prevalence, intensity of RLO infection and the mortality rates of larvae populations were of obvious positively correlations. Generally,every peak of RLO infection is always followed by a peak of mortality rate of larvae hosts, and the mortality rates of larvae hosts declined with the decreased RLO infection (see Figs 3~5). Under the transmission electron microscopy (TEM), no rickettsia-like organisms were discovered in oocytes, fertilized ovum and early embryonic phase larvae (6 h). The RLO inclusions occurred first in the D - shaped phase larvae (24 h) under histological examination. Absences of RLO in transmission electron examination of oocytes of RLO- infected adult females, fertilized ovum and early embryonic phase larvae (6h) indicated that RLO may not be transmitted transovarially. But RLO for host infection may be transmitted by contact transmission since RLO inclusions were first identified regularly in D - shaped phase larvae (24 h), while these D- shaped phase larvae were still unable to take food during hatching 24 hours. In addition, the result of epidemiological investigation showed that no observable death occurred in D- shaped larvae populations, but early obvious death occurred in larvae populations

  14. The Population Carrying Capacity of Water Resources in Yulin City

    Institute of Scientific and Technical Information of China (English)

    Lijuan; DANG; Yong; XU; Zhiqiang; WANG

    2014-01-01

    Assessing the water resource carrying capacity is beneficial for measuring the scale of industry and population agglomeration,and also avoiding the contradiction between increasing people and decreasing available water resource,due to the expansion of industry and city size.Based on the prediction model of optimum population development size,by using hydrological data,also with the demographic data from 1956 to 2010,this article analyzes and predicts the urban moderate scale under the limit of the water resource in the future of Yulin City by GIS. The main conclusions are as follows. There is growing tendency of water resources overloading. According to the result of model simulation,by2015,the overload rate of population size will be 1. 04. By 2020,the overload rate of population size will grow up to 1. 08. The oversized population mainly comes from cities and towns. The overload rate for cities and towns in 2015 and 2020 is 1. 89 and 1. 73,respectively. With the expansion of cities and industries,suburban areas could have a great potential for carrying population,because lots of suburban people may move to cities and towns according to prediction. In view of the above-mentioned facts,the population size should be controlled in a reasonable range.

  15. Parallel Optimization of a Reversible (Quantum) Ripple-Carry Adder

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock

    2008-01-01

    The design of fast arithmetic logic circuits is an important research topic for reversible and quantum computing. A special challenge in this setting is the computation of standard arithmetical functions without the generation of garbage. The CDKM-adder is a recent garbage-less reversible (quantum......) ripple-carry adder. We optimize this design with a novel parallelization scheme wherein m parallel k-bit CDKM-adders are combined to form a reversible mk-bit ripple-block carry adder with logic depth O(m+k) for a minimal logic depth O(\\sqrt{mk}), thus improving on the mk-bit CDKM-adder logic depth O......(mk). We also show designs for garbage-less reversible set-less-than circuits. We compare the circuit costs of the CDKM and parallel adder in measures of circuit delay, width, gate and transistor count, and find that the parallelized adder offers significant speedups at realistic word sizes with modest...

  16. A Novel Framework to Carry Out Cloud Penetration Test

    Directory of Open Access Journals (Sweden)

    Jianbin Hu

    2011-04-01

    Full Text Available in current cloud services, users put their data and resources into the cloud so as to enjoy the on-demand high quality applications and services. Different from the conventional services, users in cloud services lose control of their data which is instead manipulated by the large-scale cloud. Therefore, cloud service providers (CSP guarantee that the cloud which they provide is of high confidence in accuracy and integrity. Traditional penetration test is carried out manually and has low efficiency. In this paper, we propose FPTC, a novel framework of penetration test in cloud environment. In FPTC, there are managers, executors and toolkits. FPTC managers guide FPTC executors to gather information from the cloud environment, generate appropriate testing scenarios, run matched tools in the toolkit and collect test results to do evaluation. The capacity and quality of the toolkit is a key issue in FPTC. We develop a prototype in which FPTC is implemented and the experimental results show that FPTC is helpful to automatically carry out penetration test in cloud environment.

  17. Kinematic analysis of males with transtibial amputation carrying military loads

    Directory of Open Access Journals (Sweden)

    Barri L. Schnall, MPT

    2015-03-01

    Full Text Available The biomechanical responses to load carriage, a common task for dismounted troops, have been well studied in nondisabled individuals. However, with recent shifts in the rehabilitation and retention process of injured servicemembers, there remains a substantial need for understanding these responses in persons with lower-limb amputations. Temporal-spatial and kinematic gait parameters were analyzed among 10 male servicemembers with unilateral transtibial amputation (TTA and 10 uninjured male controls. Participants completed six treadmill walking trials in all combinations of two speeds (1.34 and 1.52 m/s and three loads (none, 21.8, and 32.7 kg. Persons with TTA exhibited biomechanical compensations to carried loads that are comparable to those observed in uninjured individuals. However, several distinct gait changes appear to be unique to those with TTA, notably, increased dorsiflexion (deformation of the prosthetic foot/ankle, less stance knee flexion on the prosthetic limb, and altered trunk forward lean/excursion. Such evidence supports the need for future work to assess the risk for overuse injuries with carried loads in this population in addition to guiding the development of adaptive prosthetic feet/components to meet the needs of redeployed servicemembers or veterans/civilians in physically demanding occupations.

  18. DNA microarray for simultaneous screening and detection of seven rickettsia%7种立克次体甄别检测基因芯片方法的建立

    Institute of Scientific and Technical Information of China (English)

    李灵云; 张英杰; 王升启; 刘琪琦

    2015-01-01

    目的:建立一种能同时检测7种立克次体的化学发光基因芯片法。方法根据NCBI公开发表的7种立克次体的序列设计引物和探针,制备立克次体甄别检测基因芯片。利用多重不对称PCR法扩增立克次体靶基因片段,标记的产物与基因芯片上的探针杂交,经清洗、化学发光显色后进行结果分析。在优化的多重PCR体系、杂交反应和化学发光检测条件下,评价芯片的特异性、灵敏度、重复性。用实时荧光PCR法与芯片法分别检测莫氏立克次体梯度稀释的核酸,比较两种方法的灵敏度。制备双盲模拟样本,进一步评价芯片方法的准确性。结果该研究共筛选出1对通用引物、4对特异性引物和1条立克次体属通用探针、9条特异性检测探针。该芯片检测质粒DNA的灵敏度为1.5×102~3×103拷贝/反应,检测模拟样本的灵敏度为103~104拷贝/μl。实时荧光PCR法与芯片法检测结果一致,实时荧光PCR法比芯片法灵敏度高10倍。双盲模拟样本检测符合率为100%。结论成功建立了可同时检测7种立克次体的化学发光基因芯片检测方法,为立克次体病的临床诊断和流行病学调查提供了一种新的高通量检测手段。%Objective To develop a chemiluminescence ( CL ) imaging DNA microarray method for simultaneous detection of seven rickettsiae.Methods Primers and probes were designed based on the specific sequence of seven rickettsia genomes.The probes were immobilized on the aldehyde modified glass surface to prepare DNA microarray for rickettsiae.The nucleic acids of the selected rickettsiae were amplified and labelled by multiplex PCR method, and then hybridized with microarray that was scanned after washing and chemiluminescence coloration, before the results were analyzed.Facilitated by the optimization of the multiplex PCR system, hybridization, and chemiluminescence imagination, we evaluated the

  19. Modelling of carry-over in recovery furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Fakhrai, Reza [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy

    2000-04-01

    Development of mathematical modelling of the combustion process in the furnace of recovery boilers is the subject of this work. This work as a continuation of many years of modelling efforts carried out at KTH/Vaerme- och Ugnsteknik focussed particularly on: char bed modelling; droplets-wall interaction modelling; and carry-over modelling. The char bed model has been studied. Droplets/parcels were considered as a single reactor working independently of the other droplets. The mass of the droplets was not distributed uniformly but induced in the landing place. The droplets hitting the char bed will stick to it and they are alive and part of the calculation. In this way the distribution of the mass on the char bed is only dependent on the parameters which effect flight history such as droplet/parcel diameter, boilers flow field, etc. The droplet- wall interaction model has been studied and found to be very important for obtaining the correct temperature distribution in the recovery furnace. The new approach is based on removal of droplets which hits the wall in the upper part of the recovery boiler from carryover calculation. This model has been proposed and implemented into the GRFM (General Recovery Furnace Model). The carryover modelling effort was based on mass balance in which the number and physical statistics of the droplets/parcel were estimated and the amount of unburned mass was calculated. All of the above listed models were tested together with all other models of heat and mass transfer processes in recovery furnaces using a GRFM. Three-dimensional numerical simulations of the industrial recovery boiler (63 kg/s, 82 bar, 480 deg C) were performed. The number of grid was 232,000 and the number of air ports in this simulation was 178. The air entering the furnace by these ports has different flow rates. Flow and temperature fields as well as species distributions were calculated. The results show good agreement with previously published data and modelling

  20. Carry Trade e Risco Cambial: um Conto de Dois Fatores

    Directory of Open Access Journals (Sweden)

    Alex Luiz Ferreira

    2015-12-01

    Full Text Available Retornos da estratégia de carry trade tem sido explicados usando-se funções de utilidade inseparáveis no tempo que permitem prêmios de risco voláteis. Tipicamente tais funções mimetizam as preferências de economia fechada que dependem de bens duráveis e não duráveis. Este trabalho retorna a uma classificação mais tradicional, em macroeconomia internacional, de consumo entre bens domésticos e importados. O modelo é aplicado para países que representam 98,2% do volume mundial do comércio bilateral de câmbio. Reporta-se uma melhora acentuada na significância dos betas de consumo.

  1. Rise-Time Distortion of Signal without Carrying Signal

    Science.gov (United States)

    Bukhman, N. S.

    2016-08-01

    The article deals with one-dimensional problem of rise-time distortion signal without carrying signal, that appears in the starting point intermittently, that is signal distortion at front edge or one of its derivative. The authors show that front edge of signal isn't distorted in case of propagation in unrestricted (including absorbing) area (amplitude of starting signal step or of one of its derivatives doesn't change) and move with the accuracy of vacuum light speed. The paper proves that it is the time interval shortage that causes signal loss with the route extension, but not the reduction of its starting amplitude, during which front edge of signal retains its starting value. The research presents new values for this time interval.

  2. Carbohydrate nanotechnology: hierarchical assembly using nature's other information carrying biopolymers.

    Science.gov (United States)

    Han, Xu; Zheng, Yeting; Munro, Catherine J; Ji, Yiwen; Braunschweig, Adam B

    2015-08-01

    Despite their central role in directing some of the most complex biological processes, carbohydrates--nature's other information carrying biopolymer--have been largely ignored as building blocks for synthetic hierarchical assemblies. The non-stoichiometric binding and astronomical diversity characteristic of carbohydrates could lead to tantalizingly complex assembly algorithms, but these attributes simultaneously increase the difficulty of preparing carbohydrate assemblies and anticipating their behavior. Convergences in biotechnology, nanotechnology, polymer chemistry, surface science, and supramolecular chemistry have led to many recent important breakthroughs in glycan microarrays and synthetic carbohydrate receptors, where the idiosyncrasies of carbohydrate structure and binding are increasingly considered. We hope to inspire more researchers to consider carbohydrate structure, diversity, and binding as attractive tools for constructing synthetic hierarchical assemblies.

  3. Carrying capacity in agriculture: environmental significance and some related patents.

    Science.gov (United States)

    da Silva, Alexandre M

    2009-06-01

    Agriculture is one of the most important and possibly the oldest economic activity developed by humans. This activity was developed extensively and is becoming more and more dependent on development of technologies. The goal of this manuscript was examining some patents related to technologies developed for improving crop yields. Such patents are mainly related to more efficient formulations of agrochemicals and management techniques of plants, cattle and natural resources. A brief comment is carried out about bioprospection and related problems, relating, for example the case of Cupuaçu. The article is concluded mentioning that the development of policies and management strategies that increase agricultural yield and simultaneously preserve or conserve natural resources should also be prioritized, because certainly this is the only way we have to get the real sustainability and to improve life quality abroad the world.

  4. Fatigue Analysis of Load-Carrying Fillet Welds

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tychsen, Jesper; Andersen, Jens Ulfkjær

    2006-01-01

    is a doubler plate connection, which is often applied in connection with modifications of offshore structures. As a part of the present work, fatigue tests have been performed with test specimens fabricated by the current industry standard for welded offshore steel structures. The fatigue tests show......The fatigue strength of load-carrying fillet welds is, in most codes of practice, performed neglecting the influence of bending in the weld throat section. However, some commonly applied structural details give rise to significant bending in the weld throat section. An example of such a detail...... that the degree of bending (DOB) has an influence on the fatigue lifetime. The fatigue lifetime decreases significantly when increasing the bending stress. In order to take into account the effect of the bending, a new fatigue stress definition applicable for fillet welds failing through the weld is presented...

  5. Identificación de una nueva área de infección por Rickettsias del grupo typhi: estudio de un brote de tifus en Huánuco

    Directory of Open Access Journals (Sweden)

    Rosa Mostorino E

    2003-03-01

    Full Text Available Objetivos: Investigar un brote de síndrome febril en el distrito de Punchao mediante una evaluación clínica, laboratorial y entomológica para conocer los factores asociados a la aparición de dicho brote. Materiales y métodos: Debido al reporte de tres pacientes con cuadro clínico febril asociado a cefalea, mialgias y postración en la semana epidemiológica Nº41 del año 2000, procedentes del distrito de Punchao, Humalíes, Huánuco y ante la información de presentación inusual de pacientes febriles en la última semana en dicho lugar, se decidió investigar la naturaleza y características del brote. Se definió como caso a todo paciente con cuadro febril agudo y uno de estos síntomas: cefalea, mialgias o postración; procediéndose a la búsqueda activa de éstos y a la evaluación de presencia de anticuerpos para rickettsias en suero mediante inmunofluorescencia indirecta (IFI. Se capturaron roedores y se colectaron ectoparásitos en las viviendas (roedores, animales domésticos y humanos, a fin de identificar la presencia de Rickettsias en ellos mediante IFI, aislamiento o PCR. Resultados: No se logró el aislamiento del agente causal. Se evidenció circulación de la Rickettsia sp. (serología positiva tanto en humanos (en casos y en no casos como en roedores. Se evidenció mayor presencia de malos hábitos de aseo y condiciones inadecuadas de saneamiento básico en los casos (respecto a los no casos y una disminución de los casos luego del inicio de las medidas de control. Conclusiones: Las evidencias encontradas permitieron identificar un brote de tifus en Punchao, no pudiéndose determinar la especie involucrada debido a que no se aisló el agente causal.

  6. Human embryonic stem cells carrying mutations for severe genetic disorders.

    Science.gov (United States)

    Frumkin, Tsvia; Malcov, Mira; Telias, Michael; Gold, Veronica; Schwartz, Tamar; Azem, Foad; Amit, Ami; Yaron, Yuval; Ben-Yosef, Dalit

    2010-04-01

    Human embryonic stem cells (HESCs) carrying specific mutations potentially provide a valuable tool for studying genetic disorders in humans. One preferable approach for obtaining these cell lines is by deriving them from affected preimplantation genetically diagnosed embryos. These unique cells are especially important for modeling human genetic disorders for which there are no adequate research models. They can be further used to gain new insights into developmentally regulated events that occur during human embryo development and that are responsible for the manifestation of genetically inherited disorders. They also have great value for the exploration of new therapeutic protocols, including gene-therapy-based treatments and disease-oriented drug screening and discovery. Here, we report the establishment of 15 different mutant human embryonic stem cell lines derived from genetically affected embryos, all donated by couples undergoing preimplantation genetic diagnosis in our in vitro fertilization unit. For further information regarding access to HESC lines from our repository, for research purposes, please email dalitb@tasmc.health.gov.il.

  7. Carrying photosynthesis genes increases ecological fitness of cyanophage in silico.

    Science.gov (United States)

    Hellweger, Ferdi L

    2009-06-01

    Several viruses infecting marine cyanobacteria carry photosynthesis genes (e.g. psbA, hli) that are expressed, yield proteins (D1, HLIP) and help maintain the cell's photosynthesis apparatus during the latent period. This increases energy and speeds up virus production, allowing for a reduced latent period (a fitness benefit), but it also increases the DNA size, which slows down new virus production and reduces burst size (a fitness cost). How do these genes affect the net ecological fitness of the virus? Here, this question is explored using a combined systems biology and systems ecology ('systems bioecology') approach. A novel agent-based model simulates individual cyanobacteria cells and virus particles, each with their own genes, transcripts, proteins and other properties. The effect of D1 and HLIP proteins is explicitly considered using a mechanistic photosynthesis component. The model is calibrated to the available database for Prochlorococcus ecotype MED4 and podovirus P-SSP7. Laboratory- and field-scale in silico survival, competition and evolution (gene packaging error) experiments with wild type and genetically engineered viruses are performed to develop vertical survival and fitness profiles, and to determine the optimal gene content. The results suggest that photosynthesis genes are nonessential, increase fitness in a manner correlated with irradiance, and that the wild type has an optimal gene content.

  8. Certificate size reduction in Abstraction-Carrying Code

    CERN Document Server

    Albert, Elvira; Puebla, Germán; Hermenegildo, Manuel

    2010-01-01

    Carrying Code (ACC) has recently been proposed as a framework for mobile code safety in which the code supplier provides a program together with an abstraction (or abstract model of the program) whose validity entails compliance with a predefined safety policy. The advantage of providing a (fixpoint) abstraction to the code consumer is that its validity is checked in a single pass (i.e., one iteration) of an abstract interpretation-based checker. A main challenge to make ACC useful in practice is to reduce the size of certificates as much as possible while at the same time not increasing checking time. The intuitive idea is to only include in the certificate information that the checker is unable to reproduce without iterating. We introduce the notion of reduced certificate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certificate in a single pass. Based on this notion, we instrument a generic analysis algorithm with the necessary exte...

  9. Bartonella-like bacteria carried by domestic mite species.

    Science.gov (United States)

    Kopecký, Jan; Nesvorná, Marta; Hubert, Jan

    2014-01-01

    Bacteria of the genus Bartonella are carried by haematophagous mites, ticks, fleas and flies, and attack the erythrocytes of mammals. Here we describe a Bartonella-like clade, a distinct group related to Bartonellaceae, in stored-product mites (Acari: Astigmata) and a predatory mite Cheyletus eruditus (Acari: Prostigmata) based on the analysis of cloned 16S rRNA gene sequences. By using the clade-specific primers, closely related Bartonella-like 16S rRNA sequences were amplified from both laboratory colonies and field strains of three synanthropic mite species (Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae) and a predatory mite. Altogether, sequences of Bartonella-like bacteria were found in 11 strains, but were not detected in Dermatophagoides farinae and D. pteronyssinus and two strains of L. destructor. All obtained sequences formed a separate cluster branching as a sister group to Bartonellaceae and related to other separate clusters comprising uncultured bacterial clones from human skin and hemipteran insects (Nysius plebeius and Nysius sp.). The classification of sequences into operational taxonomic units (OTUs) showed a difference between A. siro and T. putrescentiae suggesting that the Bartonella-like bacteria are different in these two mite species. However, species specific sequences in separate OTUs were observed also for C. eruditus. Possible symbiotic interactions between Bartonella-like bacteria and their mite hosts are discussed.

  10. Wildlife carrying capacities in relation to human settlement

    Directory of Open Access Journals (Sweden)

    S.K. Eltringham

    1990-09-01

    Full Text Available Human encroachment into wildlife areas, which has increased almost exponentially over the past few decades, has usually resulted in the elimination of the larger species, particularly the large mammals. This is not an inevitable consequence and this paper considers the extent to which man and wildlife can coexist. There is a linear inverse relationship between human and elephant densities and the reasons for this are discussed with particular reference to Uganda. Such a relationship does not necessarily hold for all species and the outcome of increasing human pressure on wildlife habitats varies with a variety of factors including the species concerned, the rainfall, vegetation, soil and, above all, the attitudes of the people towards wildlife. Wild animals are more likely to be tolerated if they do no harm to human activities or if the harm they do is outweighed by the benefits to be obtained from their exploitation. In many parts of Africa utilisation is likely to be the best hope for the conservation of wildlife. Some examples are given of situations in which worthwhile carrying capacities of wildlife can be maintained in the presence of human activities.

  11. Report of mecC-carrying MRSA in domestic swine

    Science.gov (United States)

    Angen, Ø.; Stegger, M.; Larsen, J.; Lilje, B.; Kaya, H.; Pedersen, K. S.; Jakobsen, A.; Petersen, A.; Larsen, A. R.

    2017-01-01

    Objectives We unexpectedly identified MRSA isolates carrying mecC (mecC-MRSA) from a Danish swine farm located in eastern Zealand. The objective of the present study was to investigate the origin of these isolates and their genetic relatedness to other mecC-MRSA isolates from Zealand. Methods WGS was used to infer the phylogenetic relationship between 19 identified mecC-MRSA isolates from the swine farm and 34 additional epidemiologically unrelated human isolates from the same geographical region of Denmark. Variations in the accessory genome were investigated by bioinformatics tools, and antibiotic susceptibility profiles were assessed by MIC determination. Results mecC-MRSA was isolated from a domestic swine farm, but not from cattle reared at the same farm. Phylogenetic analysis revealed that all mecC-MRSA isolates from both farm animals and workers formed a separate cluster, whereas human isolates from the same municipality belonged to a closely related cluster. Analysis of the accessory genome supported this relationship. Conclusions To the best of our knowledge, this is the first report of mecC-MRSA isolated from domestic swine. The investigation strongly indicates that transmission of mecC-MRSA has taken place on the swine farm between the farmers and swine. The close clustering of farm isolates and isolates from the same municipality suggests a local transmission of mecC-MRSA. PMID:27650187

  12. Saliva microbiota carry caries-specific functional gene signatures.

    Directory of Open Access Journals (Sweden)

    Fang Yang

    Full Text Available Human saliva microbiota is phylogenetically divergent among host individuals yet their roles in health and disease are poorly appreciated. We employed a microbial functional gene microarray, HuMiChip 1.0, to reconstruct the global functional profiles of human saliva microbiota from ten healthy and ten caries-active adults. Saliva microbiota in the pilot population featured a vast diversity of functional genes. No significant distinction in gene number or diversity indices was observed between healthy and caries-active microbiota. However, co-presence network analysis of functional genes revealed that caries-active microbiota was more divergent in non-core genes than healthy microbiota, despite both groups exhibited a similar degree of conservation at their respective core genes. Furthermore, functional gene structure of saliva microbiota could potentially distinguish caries-active patients from healthy hosts. Microbial functions such as Diaminopimelate epimerase, Prephenate dehydrogenase, Pyruvate-formate lyase and N-acetylmuramoyl-L-alanine amidase were significantly linked to caries. Therefore, saliva microbiota carried disease-associated functional signatures, which could be potentially exploited for caries diagnosis.

  13. 我国恙虫病立克次体(恙虫病东方体)分型研究近况%Advance research on serotype of patients with Rickettsia tsutsugamushi in China

    Institute of Scientific and Technical Information of China (English)

    郭恒彬

    2000-01-01

    @@ 恙虫病立克次体(Rickettsia tsutsugamushi,Rt)是恙虫病病原体,自从1931年定名以来,陆续发现Rt流行株,得到国际公认的有Gilliam,Karp,Kato,TA678,TA686,TA716,TA763和H1877 8个血清型[1],而Gilliam、Karp、Kato三型作为国际标准参照株.80年代初,日本[2]又分离到Kawasaki、Kuroki和Shimokoshi三型.在病原体的研究中,流行病学专家关注的问题,也就是病原体的分型,病原体的分型方法可分为表型分型和基因分型.有关Rt分型研究作简要叙述.

  14. Experimental Study on the Dynamic State of Rickettsia tsutsugamushi in Trombiculids%恙螨体内恙虫病立克次体动态变化的实验研究

    Institute of Scientific and Technical Information of China (English)

    郑小英; 黎家灿; 倪宏; 陈添胜; 陈成福

    1995-01-01

    应用PCR技术研究地里纤恙螨(Leptotrombidium deliense)实验感染恙虫病立克次体(Rickettsia tsutsugamushi)后恙螨体内立克次体DNA的动态变化.结果如下:立克次体在接种组成虫体内持续360天和经卵传递达4代;叮咬组饱食蚴体内立克次体经若蛹、若虫、成蛹达成虫期,成虫体内立克次体持续270天和经卵传递达2代,表明叮咬带立克次体鼠和经卵传递是保持恙螨亲代和子代体内立克次体动态循环的基础.

  15. 蜱斑点热群立克次体脱氧核糖核酸序列初步分析%Analysis of DNA sequences of spotted fever group rickettsia detected from ticks in Zhejing province

    Institute of Scientific and Technical Information of China (English)

    程苏云; 郑寿贵; 孟真; 叶晓东; 姜理平; 王志刚; 陆群英

    2010-01-01

    目的 了解浙江省媒介蜱斑点热群立克次体带菌状况.方法 通过扩增斑点热群立克次体外膜蛋白A基因片段,对浙江省金华市野兔、野猪寄生蜱标本进行检测分析.结果 对343份蜱标本分47组进行检测,分别从1组龟形花蜱和1组镰形扇头蜱中扩增出DNA阳性条带;经测序分析,分别命名为ZJ42和ZJ43株片段.ZJ42株与R.sp JL-95株关系较近,该株在外ompA的575~580位点有6个碱基(AAATAT)的插入缺失,可能是一个新菌株或种.ZJ43株与马赛立克次体、Rickettsia BAR-29和Rickettsia rhipicephali关系较近.结论 浙江省存在斑点热群立克次体的媒介蜱,应加强在媒介蜱,特别是镰形扇头蜱和龟形花蜱中对斑点热群立克次体的监测,并研究它们的致病性.

  16. Inverse PCR for subtyping of Acinetobacter baumannii carrying ISAba1.

    Science.gov (United States)

    Kim, Shukho; Park, Yun-Ju; Kim, Jungmin

    2016-05-01

    Acinetobacter baumannii has been prevalent in nosocomial infections, often causing outbreaks in intensive care units. ISAba1 is an insertion sequence that has been identified only in A. baumannii and its copy number varies among strains. It has been reported that ISAba1 provides a promoter for bla(OXA-51-like), bla(OXA-23-like), and bla(ampC), which are associated with the resistance of A. baumannii to carbapenems and cephalosporins. The main purpose of this study was to develop a novel inverse PCR method capable of typing A. baumannii strains. The method involves three major steps: cutting of genomic DNA with a restriction enzyme, ligation, and PCR. In the first step, bacterial genomic DNA was digested with DpnI. In the second step, the digested genomic DNAs were ligated to form intramolecular circular DNAs. In the last step, the ligated circular DNAs were amplified by PCR with primers specific for ISAba1 and the amplified PCR products were electrophoresed. Twenty-two clinical isolates of A. baumannii were used for the evaluation of the inverse PCR (iPCR) typing method. Dendrogram analysis revealed two major clusters, similar to pulsed-field gel electrophoresis (PFGE) results. Three ISAba1-associated genes--bla(ampC), bla(OXA-66-like), and csuD--were amplified and detected in the clinical isolates. This novel iPCR typing method is comparable to PFGE in its ability to discriminate A. baumannii strains, and is a promising molecular epidemiological tool for investigating A. baumannii carrying ISAba1.

  17. Estimating landscape carrying capacity through maximum clique analysis.

    Science.gov (United States)

    Donovan, Therese M; Warrington, Gregory S; Schwenk, W Scott; Dinitz, Jeffrey H

    2012-12-01

    Habitat suitability (HS) maps are widely used tools in wildlife science and establish a link between wildlife populations and landscape pattern. Although HS maps spatially depict the distribution of optimal resources for a species, they do not reveal the population size a landscape is capable of supporting--information that is often crucial for decision makers and managers. We used a new approach, "maximum clique analysis," to demonstrate how HS maps for territorial species can be used to estimate the carrying capacity, N(k), of a given landscape. We estimated the N(k) of Ovenbirds (Seiurus aurocapillus) and bobcats (Lynx rufus) in an 1153-km2 study area in Vermont, USA. These two species were selected to highlight different approaches in building an HS map as well as computational challenges that can arise in a maximum clique analysis. We derived 30-m2 HS maps for each species via occupancy modeling (Ovenbird) and by resource utilization modeling (bobcats). For each species, we then identified all pixel locations on the map (points) that had sufficient resources in the surrounding area to maintain a home range (termed a "pseudo-home range"). These locations were converted to a mathematical graph, where any two points were linked if two pseudo-home ranges could exist on the landscape without violating territory boundaries. We used the program Cliquer to find the maximum clique of each graph. The resulting estimates of N(k) = 236 Ovenbirds and N(k) = 42 female bobcats were sensitive to different assumptions and model inputs. Estimates of N(k) via alternative, ad hoc methods were 1.4 to > 30 times greater than the maximum clique estimate, suggesting that the alternative results may be upwardly biased. The maximum clique analysis was computationally intensive but could handle problems with < 1500 total pseudo-home ranges (points). Given present computational constraints, it is best suited for species that occur in clustered distributions (where the problem can be

  18. Cross-sectional survey on the prevalence of antibodies to several types of Rickettsia in human and livestock in Jiangsu province%江苏省几种主要类型人畜立克次体抗体阳性检出情况的现况调查

    Institute of Scientific and Technical Information of China (English)

    谭兆营; 李亮; 张丽娟

    2012-01-01

    Objective To investigate the main types of Rickettsia infection, prevalence of antibodies to Rickettsia and associated factors among human and livestock in Jiangsu province. Methods Five survey sites in different areas in the Province, e. g. Lishui, Peixian, Xuyi, Yixing and Binhai, were selected. Indirect immunofluorescence was applied to detect antibody IgG and IgM to seven common types of Rickettsia such as Rickettsia mooseri ( RM ) , Rickettsia heilongjiangii ( RH ) , R. tsutsugamushi, Coxiella burnetii ( CB ), Bartonella henselae/Bartonella quintana ( BH/BQ ) , Ehrlichia chaffeeusis ( MME ) and Human granulocytic anaplasmosis(HGA). Results The prevalence of BH/BQ infection was the highest in 2 562 sera in the five survey sites (24. 8% ). Prevalence of antibodies was higher in women than that in men, except prevalence of antibodies to HGA and BH/BQ, which was higher in men than that in women. Regional difference was found in all Rickettsia infections except RH/RS. Antibodies to seven types of zoonotic Rickettsia were all detected in animals. The prevalence of OT infection was the highest (31.8%). It mainly infected goats and the prevalence was different in various areas. Multivariate analysis indicated that age, sex, area and history of tick/mite bite were associated with the prevalence. Conclusions Several types of Rickettsia infection were prevalent in farming population and livestock in Jiangsu province. Infections by RM, BH/BQ and CB were dominant.%目的 了解江苏省人畜立克次体感染的主要类型、抗体阳性检出率及感染的可能影响因素.方法 按地理位置,选择江苏省溧水县、沛县、盱眙县、宜兴市和滨海县的5个调查点,采用间接免疫荧光法检测莫氏立克次体(RM)、黑龙江立克次体/西伯利亚立克次体(RH/RS)、恙虫病东方体(OT)、贝氏柯克斯体(CB)、横赛巴尔通体/五日热巴尔通体(BH/BQ)、查菲埃立克体(HME)及人粒细胞无形体(HGA)等7种常见立克次

  19. Tensorial spacetime geometries carrying predictive, interpretable and quantizable matter dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rivera Hernandez, Sergio

    2012-02-15

    Which tensor fields G on a smooth manifold M can serve as a spacetime structure? In the first part of this thesis, it is found that only a severely restricted class of tensor fields can provide classical spacetime geometries, namely those that can carry predictive, interpretable and quantizable matter dynamics. The obvious dependence of this characterization of admissible tensorial spacetime geometries on specific matter is not a weakness, but rather presents an insight: it was Maxwell theory that justified Einstein to promote Lorentzian manifolds to the status of a spacetime geometry. Any matter that does not mimick the structure of Maxwell theory, will force us to choose another geometry on which the matter dynamics of interest are predictive, interpretable and quantizable. These three physical conditions on matter impose three corresponding algebraic conditions on the totally symmetric contravariant coefficient tensor field P that determines the principal symbol of the matter field equations in terms of the geometric tensor G: the tensor field P must be hyperbolic, time-orientable and energy-distinguishing. Remarkably, these physically necessary conditions on the geometry are mathematically already sufficient to realize all kinematical constructions familiar from Lorentzian geometry, for precisely the same structural reasons. This we were able to show employing a subtle interplay of convex analysis, the theory of partial differential equations and real algebraic geometry. In the second part of this thesis, we then explore general properties of any hyperbolic, time-orientable and energy-distinguishing tensorial geometry. Physically most important are the construction of freely falling non-rotating laboratories, the appearance of admissible modified dispersion relations to particular observers, and the identification of a mechanism that explains why massive particles that are faster than some massless particles can radiate off energy until they are slower than all

  20. FPGA-Based Synthesis of High-Speed Hybrid Carry Select Adders

    Directory of Open Access Journals (Sweden)

    V. Kokilavani

    2015-01-01

    Full Text Available Carry select adder is a square-root time high-speed adder. In this paper, FPGA-based synthesis of conventional and hybrid carry select adders are described with a focus on high speed. Conventionally, carry select adders are realized using the following: (i full adders and 2 : 1 multiplexers, (ii full adders, binary to excess 1 code converters, and 2 : 1 multiplexers, and (iii sharing of common Boolean logic. On the other hand, hybrid carry select adders involve a combination of carry select and carry lookahead adders with/without the use of binary to excess 1 code converters. In this work, two new hybrid carry select adders are proposed involving the carry select and section-carry based carry lookahead subadders with/without binary to excess 1 converters. Seven different carry select adders were implemented in Verilog HDL and their performances were analyzed under two scenarios, dual-operand addition and multioperand addition, where individual operands are of sizes 32 and 64-bits. In the case of dual-operand additions, the hybrid carry select adder comprising the proposed carry select and section-carry based carry lookahead configurations is the fastest. With respect to multioperand additions, the hybrid carry select adder containing the carry select and conventional carry lookahead or section-carry based carry lookahead structures produce similar optimized performance.

  1. 河北省西部山区蜱传斑点热群立克次体分子流行病学研究%Molecular epidemiological study of tick-borne spotted fever group Rickettsia in western mountain area of Hebei province, China

    Institute of Scientific and Technical Information of China (English)

    冯帅; 吴含; 张力文; 路朝旭; 张成龙; 李志平; 张荣贞; 周慧

    2013-01-01

    Objective To investigate the prevalence of tick-borne spotted fever group Rickettsia (SFGR) in the western mountain area of Hebei province,China and to provide a scientific basis for the prevention and control of tick-borne SFGR.Methods One set of specific primers,designed according to the outer membrane protein A (OmpA) gene sequence of SFGR,were used to amplify the OmpA gene in DNA samples extracted from Haemaphysalis longicornis collected in the western mountain area of Hebei province,and the positive samples were subjected to sequencing and sequence analysis to establish the molecular phylogenetic tree.Results Of 1227 DNA samples,91 (7.42%) were positive for SFGR.The phylogenetic analysis based on nucleotide sequence showed that all detected SFGR strains were clustered together with Candidatus Rickettsia hebeiii (accession numbers:HQ651815,HQ651817,HQ651818,HQ651819,HQ651823,and HQ651824) and Rickettsia sp.Fujian strain FUJ (accession number:AF169629); these strains had the highest homology with Candidatus R.hebeiii (99.02%),followed by Rickettsia sp.Fujian strain FUJ (98.50%),Rickettsia sp.Suifen strain HLJ-054 (accession number:AF179362) and Rickettsia sp.Hulin strain HL-93 (accession number:AF179364) (98.13%),and Rickettsia sp.Japanese strain YM (accession number:U43795) (97.92%).Conclusion Tick-borne SFGR is prevalent in the western mountain area of Hebei province.Preventive measures should be taken in time to protect humans and animals from this disease.%目的 调查河北省西部山区蜱类斑点热群立克次体带菌情况,为蜱传斑点热群防控提供科学依据.方法 根据已发表斑点热群立克次体OmpA外膜蛋白基因序列设计特异性引物,对河北省西部山区采集的长角血蜱进行PCR检测,并对阳性样本进行测序和序列分析,建立分子系统进化树.结果 在1227份蜱DNA样本中检测出91份阳性,阳性率为7.42%;序列分析结果显示河北省西部山区长角血蜱携带立克

  2. 基于组间进位预测的快速进位加法器%Rapid Carry Adder Based on Carry Forecast Between Groups

    Institute of Scientific and Technical Information of China (English)

    丁宜栋; 刘昌明; 方湘艳

    2011-01-01

    为加快密码系统中大数加法的运算速度,提出并实现一种基于组间进位预测的快速进位加法器.将参与加法运算的大数进行分组,每个分组采用改进的超前进位技术以减少组内进位延时,组间通过进位预测完成不同进位状态下的加法运算,通过每个组产生的进位状态判断最终结果.性能分析表明,该进位加法器实现1024位大数加法运算的速度较快.%This paper presents and realizes a rapid carry adder based on carry forecast between groups to improve the speed of the large numbers adder in some cryptography systems. The large numbers is divided into many groups, the delay of carry-chain is reduced by carry lookahead in group. The group addition operation of different carry state is finished by carry forecast between groups. The addition sun of different carry forecast state is selected as the final result based on the carry state. Performance analysis shows that the computing speed of the carry adder is faster when realizing the 1 024 bit large numbers add operation.

  3. Dynamic Carrying Capacity Analysis of Double-Row Four-Point Contact Ball Slewing Bearing

    OpenAIRE

    Yunfeng Li; Di Jiang

    2015-01-01

    Carrying capacity is the most important performance index for slewing bearings. Maximizing the carrying capacity of slewing bearing is one pursuing goal for the bearing designer; this is usually realized by optimizing the design parameters. A method of analyzing the carrying capacity of double-row four-point contact ball slewing bearing by using dynamic carrying capacity surfaces was proposed in this paper. Based on the dynamic load carrying capacity surface of the slewing bearing, the effect...

  4. [Ecotourism carrying capacity of Hangzhou Xixi National Wetland Park in China].

    Science.gov (United States)

    Li, Rui; Rong, Liang

    2007-10-01

    In this paper, an integrated estimation on the ecotourism carrying capacity of Hangzhou Xixi National Wetland Park in China was made from the aspects of ecological carrying capacity, spatial carrying capacity, facility carrying capacity, management carrying capacity, and psychological carrying capacity. The results indicated that the tourism carrying capacity of the Park was 4 145 - 6 450 persons per day. The rational distance between man and bird was first adopted to determine the ecotourism carrying capacity of wetland, which provided an effective solution both to fully ensure bird safety and to appropriately develop wetland tourism. The estimation of psychological carrying capacity based on tourist satisfaction degree reflected more objectively the extent the tourist demands satisfied at the planning, construction and management of tour places. Such an integrated estimation method based on the distance between man and bird and the tourist satisfaction degree could be of practical and instructive significances in the planning and management of wetland parks.

  5. The Fleas (Siphonaptera) in Iran: Diversity, Host Range, and Medical Importance

    Science.gov (United States)

    Maleki-Ravasan, Naseh; Solhjouy-Fard, Samaneh; Beaucournu, Jean-Claude; Laudisoit, Anne

    2017-01-01

    Background Flea-borne diseases have a wide distribution in the world. Studies on the identity, abundance, distribution and seasonality of the potential vectors of pathogenic agents (e.g. Yersinia pestis, Francisella tularensis, and Rickettsia felis) are necessary tools for controlling and preventing such diseases outbreaks. The improvements of diagnostic tools are partly responsible for an easier detection of otherwise unnoticed agents in the ectoparasitic fauna and as such a good taxonomical knowledge of the potential vectors is crucial. The aims of this study were to make an exhaustive inventory of the literature on the fleas (Siphonaptera) and range of associated hosts in Iran, present their known distribution, and discuss their medical importance. Methodology/Principal Findings The data were obtained by an extensive literature review related to medically significant fleas in Iran published before 31st August 2016. The flea-host specificity was then determined using a family and subfamily-oriented criteria to further realize and quantify the shared and exclusive vertebrate hosts of fleas among Iran fleas. The locations sampled and reported in the literature were primarily from human habitation, livestock farms, poultry, and rodents’ burrows of the 31 provinces of the country. The flea fauna were dominated by seven families, namely the Ceratophyllidae, Leptopsyllidae, Pulicidae, Ctenophthalmidae, Coptopsyllidae, Ischnopsyllidae and Vermipsyllidae. The hosts associated with Iran fleas ranged from the small and large mammals to the birds. Pulicidae were associated with 73% (56/77) of identified host species. Flea-host association analysis indicates that rodents are the common hosts of 5 flea families but some sampling bias results in the reduced number of bird host sampled. Analyses of flea-host relationships at the subfamily level showed that most vertebrates hosted fleas belgonging to 3 subfamilies namely Xenopsyllinae (n = 43), Ctenophthalminae (n = 20) and

  6. Chloroform-Methanol Residue of Coxiella burnetii Markedly Potentiated the Specific Immunoprotection Elicited by a Recombinant Protein Fragment rOmpB-4 Derived from Outer Membrane Protein B of Rickettsia rickettsii in C3H/HeN Mice.

    Directory of Open Access Journals (Sweden)

    Wenping Gong

    Full Text Available The obligate intracellular bacteria, Rickettsia rickettsii and Coxiella burnetii, are the potential agents of bio-warfare/bio-terrorism. Here C3H/HeN mice were immunized with a recombinant protein fragment rOmp-4 derived from outer membrane protein B, a major protective antigen of R. rickettsii, combined with chloroform-methanol residue (CMR extracted from phase I C. burnetii organisms, a safer Q fever vaccine. These immunized mice had significantly higher levels of IgG1 and IgG2a to rOmpB-4 and interferon-γ (IFN-γ and tumor necrosis factor-α (TNF-α, two crucial cytokines in resisting intracellular bacterial infection, as well as significantly lower rickettsial loads and slighter pathological lesions in organs after challenge with R. rickettsii, compared with mice immunized with rOmpB-4 or CMR alone. Additionally, after challenge with C. burnetii, the coxiella loads in the organs of these mice were significantly lower than those of mice immunized with rOmpB-4 alone. Our results prove that CMR could markedly potentiate enhance the rOmpB-4-specific immunoprotection by promoting specific and non-specific immunoresponses and the immunization with the protective antigen of R. rickettsii combined with CMR of C. burnetii could confer effective protection against infection of R. rickettsii or C. burnetii.

  7. 罗非鱼类立克次氏体病的组织病理学观察%Histopathological Observation of Disease of Rickettsia-like Organism in Tilapia (Oreochromis niloticus)

    Institute of Scientific and Technical Information of China (English)

    戚瑞荣; 唐绍林; 崔龙波; 雷燕; 马家好

    2016-01-01

    本文主要研究感染类立克次氏体(Rickettsia-like organism,RLO)的养殖罗非鱼(Oreochromis aureus ♂×Oreochromis niloticus♀)肝、脾、肾、肠、鳃和心脏的组织病理变化.感染类立克次氏体的罗非鱼各器官广布粗糙不圆整的白色小结节,这些结节为肉芽肿坏死灶,分层不典型,与周围健康组织的界限不甚明显;严重病变的组织坏死区域较大,与周围明显增生的细胞形成清晰的巨大“肉瘤”状肿物.经吉姆萨-瑞氏染色后,在病变组织内,尤其是脾肾组织的巨噬细胞胞质内可见蓝紫色球状或颗粒样、成簇分布的类立克次氏体.这些发现可为罗非鱼类立克次氏体病的病理学诊断提供依据.

  8. An investigation of Bartonella spp., Rickettsia typhi, and Seoul hantavirus in rats (Rattus spp.) from an inner-city neighborhood of Vancouver, Canada: is pathogen presence a reflection of global and local rat population structure?

    Science.gov (United States)

    Himsworth, Chelsea G; Bai, Ying; Kosoy, Michael Y; Wood, Heidi; DiBernardo, Antonia; Lindsay, Robbin; Bidulka, Julie; Tang, Patrick; Jardine, Claire; Patrick, David

    2015-01-01

    Urban Norway and black rats (Rattus norvegicus and Rattus rattus) are reservoirs for variety of zoonotic pathogens. Many of these pathogens, including Rickettsia typhi, Bartonella spp., and Seoul hantavirus (SEOV), are thought to be endemic in rat populations worldwide; however, past field research has found these organisms to be absent in certain rat populations. Rats (Rattus spp.) from an inner city neighborhood of Vancouver, Canada, were tested for exposure to and/or infection with SEOV and R. typhi (using serology and PCR), as well as Bartonella spp. (using culture and sequencing). Approximately 25% of 404 rats tested were infected with Bartonella tribocorum, which demonstrated significant geographic clustering within the study area. Infection was associated with both season and sexual maturity. Seroreactivity against R. typhi and SEOV was observed in 0.36% and 1.45% of 553 rats tested, respectively, although PCR screening results for these pathogens were negative, suggesting that they are not endemic in the study population. Overall, these results suggest that the geographic distribution of rat-associated zoonoses, including R. typhi, SEOV, and Bartonella spp., is less ubiquitous than previously appreciated, and is likely dependent on patterns of dispersion and establishment of the rat reservoir host. Further study on global and local Rattus spp. population structures may help to elucidate the ecology of zoonotic organisms in these species.

  9. Psychophysical determination of load carrying capacity for a 1-h work period by Chinese males.

    Science.gov (United States)

    Wu, S P; Chen, C C

    2001-09-15

    This study used the psychophysical approach to examine the effects of container width, the presence or absence of container handles, and different load-carrying frequencies and distances on the maximum acceptable weight carried and the resulting response (heart rate and rating of perceived exertion) by well-conditioned males for a 1-h work period. After training, 12 male subjects performed a load-carrying task at knuckle height. Each subject performed 30 different carrying combinations. The conditions examined were container width, from 15.2 to 55.9 cm; carrying frequency, from 1 carry to 5 carries/min; and carrying distance from 1 to 6 m. The results were compared with prior studies and led to the following conclusions: (1) the use of container handles leads to the subjects carrying a significantly higher maximum acceptable weight than when containers do not have handles, which differs from the results of a previous study by Morrissey and Liou; (2) there were significant reductions in the maximum acceptable carrying weight with increases in container width, frequency and distance; (3) the presence or absence of container handles, different frequencies and load-carrying distances had significant effects on heart rate, although the effect of container width was not significant. In addition, the various frequencies and distances for load carrying had significant interaction effects on heart rate; (4) the effects of various frequencies and load-carrying distances on the rating of perceived exertion were statistically significant. The most stressed body parts were the wrists and arms.

  10. Sdelki carry trade ne roskosh, a sredstvo nakoplenija / Darius Gecevicius, Dmitri Fokin

    Index Scriptorium Estoniae

    Gecevicius, Darius

    2007-01-01

    Strateegia carry trade kasutamisest valuutaturgudel. Carry trade on tehing, mis enamasti toimub valuutaturul, kus investor laenab raha sisse valuutas, mille intressid on madalamad ning paigutab selle valuutas, kus intressid on kõrgemad. Diagramm

  11. 46 CFR 150.160 - Carrying a cargo as an exception to the compatibility chart.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Carrying a cargo as an exception to the compatibility... BULK DANGEROUS CARGOES COMPATIBILITY OF CARGOES § 150.160 Carrying a cargo as an exception to the compatibility chart. The Operator of a vessel having on board a cargo carried as an exception under §...

  12. 25 CFR 161.204 - How are carrying capacities and stocking rates established?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How are carrying capacities and stocking rates... WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS General Provisions § 161.204 How are carrying capacities..., review and adjust the carrying capacity of each range unit by determining the number of livestock,...

  13. Campaign for Right to Carry Concealed Guns on Campuses Gains Traction

    Science.gov (United States)

    Wiseman, Rachel

    2012-01-01

    Five years after the Virginia Tech massacre prompted a student in Texas to start a Facebook page in favor of the right to carry concealed weapons on college campuses, the resulting group, Students for Concealed Carry, has advanced its cause. In more than a dozen states, legislation has been introduced to allow the carrying of concealed firearms on…

  14. 36 CFR 1005.4 - Commercial passenger-carrying motor vehicles.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Commercial passenger-carrying motor vehicles. 1005.4 Section 1005.4 Parks, Forests, and Public Property PRESIDIO TRUST COMMERCIAL AND PRIVATE OPERATIONS § 1005.4 Commercial passenger-carrying motor vehicles. Passenger-carrying...

  15. 49 CFR 395.3 - Maximum driving time for property-carrying vehicles.

    Science.gov (United States)

    2010-10-01

    ... used by it to drive a property-carrying commercial motor vehicle, nor shall any such driver drive a property-carrying commercial motor vehicle: (1) More than 11 cumulative hours following 10 consecutive... commercial motor vehicle to drive, nor shall any driver drive a property-carrying commercial motor...

  16. Design of High-Speed Hybrid Carry Select Adders using VHDL

    OpenAIRE

    Mr. Vijay V. Gotmare; Dr. Pankaj Agarwal

    2016-01-01

    Carry select adder (CSA) is a square-root time high-speed adder. CSA is one of the fastest adders used in many data processing systems to perform fast arithmetic operations. In this project we propose to design hybrid carry select adders with a focus on high speed. CSA is a compromise between the longer delay Ripple carry adder (RCA) and the shorter delay Carry look-ahead adder (CLA). Conventionally carry select adders are realize using the full adders and 2:1 multiplexers. On the other hand ...

  17. Dynamic Carrying Capacity Analysis of Double-Row Four-Point Contact Ball Slewing Bearing

    Directory of Open Access Journals (Sweden)

    Yunfeng Li

    2015-01-01

    Full Text Available Carrying capacity is the most important performance index for slewing bearings. Maximizing the carrying capacity of slewing bearing is one pursuing goal for the bearing designer; this is usually realized by optimizing the design parameters. A method of analyzing the carrying capacity of double-row four-point contact ball slewing bearing by using dynamic carrying capacity surfaces was proposed in this paper. Based on the dynamic load carrying capacity surface of the slewing bearing, the effect of changes of the bearing design parameters, such as axial clearance, raceway groove radius coefficient, and contact angle, on the dynamic carrying capacity of the slewing bearing was researched; the trend and the degree of the effect of the micro changes of the bearing design parameters on the dynamic load carrying capacity of the bearing were discussed, and the results provide the basis for optimizing the design parameter of this type of slewing bearing.

  18. Seroprevalencia de la infección por Borrelia burgdorgferi y Rickettsia conorii en población humana y canina de la zona básica de salud de San Andrés del Rabanedo (León, España)

    OpenAIRE

    1997-01-01

    FUNDAMENTOS: Se estudia la seroprevalencia de la infección por Borrelia burgdorferi y Rickettsia conorii en población humana y canina para conocer la situación de ambas en humanos, al mismo tiempo que la significación del perro, como indicador de la circulación de estos agentes entre aquéllos, en la Zona de Salud de San Andrés del Rabanedo, León. MÉTODO: Se realizó un estudio en 98 sueros humanos y 95 caninos (de diversas razas y aptitudes) frente a B. burgdorferi (títulos de positividad > a ...

  19. STUDIES ON RICKETTSIA-LIKE ORGANISMS INFECTING ERIOCHEIR SINENSIS%中华绒螯蟹感染类立克次氏体微生物的研究

    Institute of Scientific and Technical Information of China (English)

    王进科; 朱清顺; 周刚; 张凤英

    2003-01-01

    对"颤抖病"中华绒螯蟹病蟹病理组织超显微结构观察表明,在病蟹鳃上皮细胞、肝胰腺细胞及血淋巴细胞中存在大量类立克次氏体(rickettsia-like organism,RLO)微生物.RLO主要以包含体形式存在于寄主细胞的细胞质中,同时也能散在或群居状存在于包含体外的细胞质内.RLO细胞形态主要有两类,即初级体细胞型和中间体细胞型.初级体RLO表现为体积较小、电子密度深染的球状颗粒.中间体RLO呈现球状、椭圆体及棒状等多种细胞形态.中间体RLO能以二分裂和出芽两种方式繁殖.人工感染实验表明,RLO能通过水体经鳃感染健康蟹,使其表现颤抖病症状.血淋巴细胞中RLO的存在及电镜对不同发病时期病蟹组织的观察结果说明,RLO能够依靠血淋巴循环迅速从最初感染的鳃组织向肝胰腺扩散,形成系统感染,导致器官组织细胞机能紊乱. 图版2 参24

  20. Quantifying spatially derived carrying capacity occupation: Framework for characterisation modelling and application to terrestrial acidification

    DEFF Research Database (Denmark)

    Bjørn, Anders; Margni, M.; Bulle, C.;

    The popularity of the ecological footprint method and the planetary boundaries concept shows an increasing interest among decision makers in comparing environmental impacts to carrying capacities of natural systems. Recently carrying capacity-based normalisation references were developed for impact...... categories at midpoint level in LCA. These references are operational and their meaning can easily be communicated to practitioners and decision makers. Yet they do not capture potentially important spatial variations in carrying capacities. To overcome this weakness we propose to integrate carrying capacity...... in characterisation factors (CFs) as an alternative to using carrying capacity as reference information in normalisation references. We developed a generic mathematical expression for a spatially differentiated CF, which allows expressing impact scores as occupation of carrying capacity in units of km...

  1. Effects of a Fluctuating Carrying Capacity on the Generalized Malthus-Verhulst Model

    Directory of Open Access Journals (Sweden)

    Héctor Calisto

    2014-01-01

    Full Text Available We consider a generalized Malthus-Verhulst model with a fluctuating carrying capacity and we study its effects on population growth. The carrying capacity fluctuations are described by a Poissonian process with an exponential correlation function. We will find an analytical expression for the average of a number of individuals and show that even in presence of a fluctuating carrying capacity the average tends asymptotically to a constant quantity.

  2. ANALYSIS OF ABILITY FOR IGNITING METHANE OF WATER-CARRYING EXPLOSIVES

    Institute of Scientific and Technical Information of China (English)

    陆守香

    1997-01-01

    In this paper, the ability to ignite methane of water-carrying explosives is discussed in detail. The difference of the safety towards methane of water- carrying explosives and ammonite is analysed comparatively. It is shown that the process of detonation reaction, the duration of flame by combustible residues of detonation and the fineness of cooling salt in detonation products are important factors of the safety of explosive towards methane. Water-carrying explosives are safer than ammonite used in coal mines.

  3. Design & Analysis of Low Power, Area-Efficient Carry Select Adder

    Directory of Open Access Journals (Sweden)

    Shuchi Verma

    2014-03-01

    Full Text Available This paper deals with the design & analysis of Carry Select Adder (CSLA & Carry lookahead adder (CLA. Adders are designed using 0.18µm CMOS process technology & simulated with Modelsim6.3f. The adder designs, Regular CSLA, modified CSLA using BEC, modified CSLA without using multiplexer, modified CSLA using D-Latch & Carry lookahead adders in 4-bit, 16-bit, 32-bit, are compared with the simulated results on the basis area.

  4. Effects of a Fluctuating Carrying Capacity on the Generalized Malthus-Verhulst Model

    OpenAIRE

    Héctor Calisto; Chandía, Kristopher J.; Mauro Bologna

    2014-01-01

    We consider a generalized Malthus-Verhulst model with a fluctuating carrying capacity and we study its effects on population growth. The carrying capacity fluctuations are described by a Poissonian process with an exponential correlation function. We will find an analytical expression for the average of a number of individuals and show that even in presence of a fluctuating carrying capacity the average tends asymptotically to a constant quantity.

  5. Estimating Recreational Carrying Capacity of Gheisary Protected Area in Chaharmahal & Bakhtiari Province

    OpenAIRE

    Sheikh, A; Jafari, A.; Setoodeh, A

    2014-01-01

    It is now certain that to ensure a long term sustainable development, protected areas, the favored destinations for ecotourism, required a well written planning management. Each destination however has limited capability which is called “carrying capacity” to invite visitors. Physical, real (ecological) and effective (manageable) are different kinds of carrying capacity. The current study presented these varieties of carrying capacities for Gheisary protected area, stretched over 10,000 ha in...

  6. Research on Carrying Capacity of Water Resource Based on Multi-reservoir Regulation

    OpenAIRE

    Liu Renyuan; Li Lei; Li Hua; Huang Qiang

    2013-01-01

    Analyze the level of Carrying Capacity of Water Resources; evaluate the condition of e region social, economic and ecological environment comprehensive and sustainable development. This study is based on analyzing the meaning of water resources carrying capacity, take water resources of the Midwest of Shenzhen City an example., by the way of the “Coordinated and sustainable development” theory, found the model of the Carrying Capacity of Water Resources, Calculated and analyzed. Water efficie...

  7. Habitat-mediated carry-over effects lead to context-dependent outcomes of species interactions.

    Science.gov (United States)

    Van Allen, Benjamin G; Rudolf, Volker H W

    2015-11-01

    When individuals disperse, their performance in newly colonized habitats can be influenced by the conditions they experienced in the past, leading to environmental carry-over effects. While carry-over effects are ubiquitous in animal and plant systems, their impact on species interactions and coexistence are largely ignored in traditional coexistence theory. Here we used a combination of modelling and experiments with two competing species to examine when and how such environmental carry-over effects influence community dynamics and competitive exclusions. We found that variation in the natal habitat quality of colonizing individuals created carry-over effects which altered competitive coefficients, fecundity and mortality rates, and extinction probabilities of both species. As a consequence, the dynamics of competitive exclusion within and across habitat types was contingent on the natal habitat of colonizing individuals, indicating that spatial carry-over effects can fundamentally alter the dynamics and outcome of interspecific competition. Interestingly, carry-over effects persistently influenced dynamics in systems with interspecific competition for the entire duration of the experiment while carry-over effects were transient and only influenced initial dynamics in single-species populations. Thus carry-over effects can be enhanced by species interactions, suggesting that their long-term effects may often not be accurately predicted by single-species studies. Given that carry-over effects are ubiquitous in heterogeneous landscapes, our results provide a novel mechanism that could help explain variation in the structure of natural communities.

  8. The Association Between Weapon Carrying and Health Risk Behaviors Among Adolescent Students in Bangkok, Thailand.

    Science.gov (United States)

    Saiphoklang, On-Anong; Wongboonsin, Kua; Wongboonsin, Patcharawalai; Perngparn, Usaneya; Cottler, Linda B

    2015-07-30

    Carrying weapons is a significant social and public health problem worldwide, especially among adolescents. The present study examined the association between weapon carrying and related risk behaviors among Thai adolescents. A cross-sectional study of 2,588 high school and vocational school students aged 11 to 19 years from 26 schools in Bangkok, Thailand, was conducted in 2014. This study found that 7.8% of youth reported having carried a weapon in the past 12 months. The high prevalence of weapon carrying was reported by male students, and males were more likely to have reported carrying a weapon than females. The association between weapon carrying and the health risk behaviors like drinking, smoking, any drug use, and physical fighting were significant with higher odds of weapon carrying in all models. Among males, weapon carrying was related to drinking and smoking, any drug use, physical fighting, and school type. Among females, suicidal thoughts were significantly related along with drinking and smoking, any drug use, and physical fighting. Having a mother who used substances was significant only among females. These data could be used for further interventions about weapon carrying to reduce violence.

  9. Review on the Evaluation System of Public Safety Carrying Capacity about Small Town Community

    Institute of Scientific and Technical Information of China (English)

    Ming; SUN; Tianyu; ZHU

    2014-01-01

    Recently,small town community public safety problem has been increasingly highlighted,but its research is short on public safety carrying capacity. Through the investigation and study of community public safety carrying capacity,this paper analyzes the problem of community public safety in our country,to construct index evaluation system of public safety carrying capacity in small town community. DEA method is used to evaluate public safety carrying capacity in small town community,to provide scientific basis for the design of support and standardization theory about small town community in public safety planning.

  10. An Area-Efficient Carry Select Adder Design by using 180 nm Technology

    OpenAIRE

    Garish Kumar Wadhwa; Amit Grover; Neeti Grover; GurpreetSingh

    2013-01-01

    In this paper, we proposed an area-efficient carry select adder by sharing the common Boolean logic term. After logic simplification and sharing partial circuit, we only need one XOR gate and one inverter gate in each summation operation as well as one AND gate and one inverter gate in each carry-out operation. Through the multiplexer, we can select the correct output result according to the logic state of carry-in signal. In this way, the transistor count in a 32-bit carry select adder can b...

  11. An Area-Efficient Carry Select Adder Design by using 180 nm Technology

    Directory of Open Access Journals (Sweden)

    Garish Kumar Wadhwa

    2013-02-01

    Full Text Available In this paper, we proposed an area-efficient carry select adder by sharing the common Boolean logic term. After logic simplification and sharing partial circuit, we only need one XOR gate and one inverter gate in each summation operation as well as one AND gate and one inverter gate in each carry-out operation. Through the multiplexer, we can select the correct output result according to the logic state of carry-in signal. In this way, the transistor count in a 32-bit carry select adder can be greatly reduced from 1947 to 960.

  12. Specifying the Role of Exposure to Violence and Violent Behavior on Initiation of Gun Carrying: A Longitudinal Test of Three Models of Youth Gun Carrying

    Science.gov (United States)

    Spano, Richard; Pridemore, William Alex; Bolland, John

    2012-01-01

    Two waves of longitudinal data from 1,049 African American youth living in extreme poverty are used to examine the impact of exposure to violence (Time 1) and violent behavior (Time 1) on first time gun carrying (Time 2). Multivariate logistic regression results indicate that (a) violent behavior (Time 1) increased the likelihood of initiation of…

  13. 46 CFR 98.25-5 - How anhydrous ammonia may be carried.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to...

  14. Toddlers actively reorganize their whole body coordination to maintain walking stability while carrying an object.

    Science.gov (United States)

    Hsu, Wen-Hao; Miranda, Daniel L; Chistolini, Trevor L; Goldfield, Eugene C

    2016-10-01

    Balanced walking involves freely swinging the limbs like pendula. However, children immediately begin to carry objects as soon as they can walk. One possibility for this early skill development is that whole body coordination during walking may be re-organized into loosely coupled collections of body parts, allowing children to use their arms to perform one function, while the legs perform another. Therefore, this study examines: 1) how carrying an object affects the coordination of the arms and legs during walking, and 2) if carrying an object influences stride length and width. Ten healthy toddlers with 3-12 months of walking experience were recruited to walk barefoot while carrying or not carrying a small toy. Stride length, width, speed, and continuous relative phase (CRP) of the hips and of the shoulders were compared between carrying conditions. While both arms and legs demonstrated destabilization and stabilization throughout the gait cycle, the arms showed a reduction in intra-subject coordination variability in response to carrying an object. Carrying an object may modify the function of the arms from swinging for balance to maintaining hold of an object. The observed period-dependent changes of the inter-limb coordination of the hips and of the shoulders also support this interpretation. Overall, these findings support the view that whole-body coordination patterns may become partitioned in particular ways as a function of task requirements.

  15. 48 CFR 19.707 - The Small Business Administration's role in carrying out the program.

    Science.gov (United States)

    2010-10-01

    ... Subcontracting Program 19.707 The Small Business Administration's role in carrying out the program. (a) Under the... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false The Small Business Administration's role in carrying out the program. 19.707 Section 19.707 Federal Acquisition Regulations...

  16. Risk-premia, Carry-trade Dynamics, and Economic Value of Currency Speculation

    DEFF Research Database (Denmark)

    Wagner, Christian

    2012-01-01

    -cited ‘forward bias puzzle’ originates from the omission of the risk-premium in standard UIP tests. Consistent with its popularity among market professionals, the carry-trade strategy can be rationalized as it systematically collects risk-premia, however, the economic value generated by bilateral carry-trades...

  17. Gun Cultures or Honor Cultures? Explaining Regional and Race Differences in Weapon Carrying

    Science.gov (United States)

    Felson, Richard B.; Pare, Paul-Philippe

    2010-01-01

    We use the National Violence against Women (and Men) Survey to examine the effects of region and race on the tendency to carry weapons for protection. We find that Southern and Western whites are much more likely than Northern whites to carry guns for self-protection, controlling for their risk of victimization. The difference between Southern and…

  18. CERTAINTY EQUIVALENCE FOR DETERMINATION OF OPTIMAL FERTILIZER APPLICATION RATES WITH CARRY-OVER

    OpenAIRE

    Taylor, C. Robert

    1983-01-01

    This note demonstrates that a certain class of stochastic problems for determination of optimal fertilizer application rates in the presence of fertilizer carry-over can be simplified to static, certainly equivalent problems. Conditions required for certainty equivalence to hold are: (1) fertilizer carry-over is agronomically equivalent to applied fertilizer; and (2) some addition of fertilizer is optimal in every decision period.

  19. The application of a phosphorus mass balance model for estimating the carrying capacity of Lake Kariba

    OpenAIRE

    MHLANGA, Lindah; MHLANGA, Wilson; MWERA, Paul

    2013-01-01

    The aim of this study was to use an empirical mass balance equation to estimate the carrying capacity of Lake Kariba, where cage culture for Nile tilapia Oreochromis niloticus has been practiced since 1996. The carrying capacity for the lake was estimated at 33.2 × 103 t per year using the Dillon-Rigler phosphorus budget model.

  20. Complete genome sequences of Incl1 Plasmids carrying extended-spectrum B-Lactamase genes

    NARCIS (Netherlands)

    Brouwer, M.S.M.; Bossers, A.; Harders, F.; Essen-Zandbergen, van A.; Mevius, D.J.; Smith, H.E.

    2014-01-01

    Extended spectrum beta-lactamases (ESBLs) confer resistance to clinically relevant antibiotics. Often, the resistance genes are carried by conjugative plasmids which are responsible for dissemination. Five IncI1 plasmids carrying ESBLs from commensal and clinical Escherichia coli isolates were compl