Full Text Available Abstract Background The Rickettsia genus includes 25 validated species, 17 of which are proven human pathogens. Among these, the pathogenicity varies greatly, from the highly virulent R. prowazekii, which causes epidemic typhus and kills its arthropod host, to the mild pathogen R. africae, the agent of African tick-bite fever, which does not affect the fitness of its tick vector. Results We evaluated the clonality of R. africae in 70 patients and 155 ticks, and determined its genome sequence, which comprises a circular chromosome of 1,278,540 bp including a tra operon and an unstable 12,377-bp plasmid. To study the genetic characteristics associated with virulence, we compared this species to R. prowazekii, R. rickettsii and R. conorii. R. africae and R. prowazekii have, respectively, the less and most decayed genomes. Eighteen genes are present only in R. africae including one with a putative protease domain upregulated at 37°C. Conclusion Based on these data, we speculate that a loss of regulatory genes causes an increase of virulence of rickettsial species in ticks and mammals. We also speculate that in Rickettsia species virulence is mostly associated with gene loss. The genome sequence was deposited in GenBank under accession number [GenBank: NZ_AAUY01000001].
Kimita, Gathii; Mutai, Beth; Nyanjom, Steven Ger; Wamunyokoli, Fred; Waitumbi, John
Rickettsia africae, the etiological agent of African tick bite fever, is widely distributed in sub-Saharan Africa. Contrary to reports of its homogeneity, a localized study in Asembo, Kenya recently reported high genetic diversity. The present study aims to elucidate the extent of this heterogeneity by examining archived Rickettsia africae DNA samples collected from different eco-regions of Kenya. To evaluate their phylogenetic relationships, archived genomic DNA obtained from 57 ticks a priori identified to contain R. africae by comparison to ompA, ompB and gltA genes was used to amplify five rickettsial genes i.e. gltA, ompA, ompB, 17kDa and sca4. The resulting amplicons were sequenced. Translated amino acid alignments were used to guide the nucleotide alignments. Single gene and concatenated alignments were used to infer phylogenetic relationships. Out of the 57 DNA samples, three were determined to be R. aeschlimanii and not R. africae. One sample turned out to be a novel rickettsiae and an interim name of "Candidatus Rickettsia moyalensis" is proposed. The bonafide R. africae formed two distinct clades. Clade I contained 9% of the samples and branched with the validated R. africae str ESF-5, while clade II (two samples) formed a distinct sub-lineage. This data supports the use of multiple genes for phylogenetic inferences. It is determined that, despite its recent emergence, the R. africae lineage is diverse. This data also provides evidence of a novel Rickettsia species, Candidatus Rickettsia moyalensis.
Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions. Copyright © 2012 Elsevier GmbH. All rights reserved.
Wieten, Rosanne W.; Hovius, Joppe W. R.; Groen, Emilie J.; van der Wal, Allard C.; de Vries, Peter J.; Beersma, Matthijs F. C.; Tijsse-Klasen, Ellen; Sprong, Hein; Grobusch, Martin P.
African tick-bite fever (ATBF) is frequently diagnosed in The Netherlands in travelers returning from South Africa. It is caused by Rickettsia africae and diagnosis is based on travel history and clinical presentation and usually confirmed by detecting serum antibodies against rickettsiae of the
Mungkin sebagian orang belum mengetahui bahkan baru mendengar tentang Rickettsia. Di Indonesia, skrining terhadap kasus Rickettsia ini masih jarang dan belum banyak dilakukan penelitian. Rickettsia sebenarnya merupakan bakteri yang mempunyai sifat parasit obligat intrasel uler, berukuran kecil (0,3-0,5 x 0,8-2,0 µm), mempunyai bentuk coccobacilli, gram negatif, tidak berflagel (kecuali Rickettsia prowazekii), dan mengalami pembelahan ganda dalam set pejamu. Rickettsia dianggap sebagai kelompo...
Akter, Arzuba; Ooka, Tadasuke; Gotoh, Yasuhiro; Yamamoto, Seigo; Fujita, Hiromi; Terasoma, Fumio; Kida, Kouji; Taira, Masakatsu; Nakadouzono, Fumiko; Gokuden, Mutsuyo; Hirano, Manabu; Miyashiro, Mamoru; Inari, Kouichi; Shimazu, Yukie; Tabara, Kenji; Toyoda, Atsushi; Yoshimura, Dai; Itoh, Takehiko; Kitano, Tomokazu; Sato, Mitsuhiko P; Katsura, Keisuke; Mondal, Shakhinur Islam; Ogura, Yoshitoshi; Ando, Shuji; Hayashi, Tetsuya
Rickettsiae are obligate intracellular bacteria that have small genomes as a result of reductive evolution. Many Rickettsia species of the spotted fever group (SFG) cause tick-borne diseases known as "spotted fevers". The life cycle of SFG rickettsiae is closely associated with that of the tick, which is generally thought to act as a bacterial vector and reservoir that maintains the bacterium through transstadial and transovarial transmission. Each SFG member is thought to have adapted to a specific tick species, thus restricting the bacterial distribution to a relatively limited geographic region. These unique features of SFG rickettsiae allow investigation of how the genomes of such biologically and ecologically specialized bacteria evolve after genome reduction and the types of population structures that are generated. Here, we performed a nationwide, high-resolution phylogenetic analysis of Rickettsia japonica, an etiological agent of Japanese spotted fever that is distributed in Japan and Korea. The comparison of complete or nearly complete sequences obtained from 31 R. japonica strains isolated from various sources in Japan over the past 30 years demonstrated an extremely low level of genomic diversity. In particular, only 34 single nucleotide polymorphisms were identified among the 27 strains of the major lineage containing all clinical isolates and tick isolates from the three tick species. Our data provide novel insights into the biology and genome evolution of R. japonica, including the possibilities of recent clonal expansion and a long generation time in nature due to the long dormant phase associated with tick life cycles. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Fournier, P E; Roux, V; Caumes, E; Donzel, M; Raoult, D
African tick-bite fever, caused by Rickettsia africae and transmitted by Amblyomma ticks, is an emerging rickettsiosis in southern Africa. Because of increased tourism to this area, several cases in tourists have been reported recently. We report 13 cases of R. africae infection diagnosed in France that occurred in competitors returning from an adventure race in South Africa and compare our data with previously reported findings. Most of our patients presented with fever, headache, multiple inoculation eschars, and regional lymphadenopathies, but only 15.4% had a cutaneous rash. Diagnosis was confirmed either by isolation of R. africae from an eschar biopsy specimen or by serological methods, including cross-adsorption between R. africae and Rickettsia conorii. The purpose of this study was to raise physicians' awareness of R. africae infections in an attempt to facilitate the rapid diagnosis and treatment of imported African tick-bite fever in developed countries.
Leulmi, Hamza; Socolovschi, Cristina; Laudisoit, Anne; Houemenou, Gualbert; Davoust, Bernard; Bitam, Idir; Raoult, Didier; Parola, Philippe
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.
Halajian, Ali; Palomar, Ana M; Portillo, Aránzazu; Heyne, Heloise; Luus-Powell, Wilmien J; Oteo, José A
Ticks are involved in the epidemiology of several human pathogens including spotted fever group (SFG) Rickettsia spp., Coxiella burnetii and Bartonella spp. Human diseases caused by these microorganisms have been reported from South Africa. The presence of SFG Rickettsia spp., C. burnetii and Bartonella spp. was investigated in 205 ticks collected from domestic and wild animals from Western Cape and Limpopo provinces (South Africa). Rickettsia massiliae was detected in 10 Amblyomma sylvaticum and 1 Rhipicephalus simus whereas Rickettsia africae was amplified in 7 Amblyomma hebraeum. Neither C. burnetii nor Bartonella spp. was found in the examined ticks. This study demonstrates the presence of the tick borne pathogen R. massiliae in South Africa (Western Cape and Limpopo provinces), and corroborates the presence of the African tick-bite fever agent (R. africae) in this country (Limpopo province). Copyright © 2015 Elsevier GmbH. All rights reserved.
Roderick F Felsheim
Full Text Available Rickettsia peacockii, also known as the East Side Agent, is a non-pathogenic obligate intracellular bacterium found as an endosymbiont in Dermacentor andersoni ticks in the western USA and Canada. Its presence in ticks is correlated with reduced prevalence of Rickettsia rickettsii, the agent of Rocky Mountain Spotted Fever. It has been proposed that a virulent SFG rickettsia underwent changes to become the East Side Agent. We determined the genome sequence of R. peacockii and provide a comparison to a closely related virulent R. rickettsii. The presence of 42 chromosomal copies of the ISRpe1 transposon in the genome of R. peacockii is associated with a lack of synteny with the genome of R. rickettsii and numerous deletions via recombination between transposon copies. The plasmid contains a number of genes from distantly related organisms, such as part of the glycosylation island of Pseudomonas aeruginosa. Genes deleted or mutated in R. peacockii which may relate to loss of virulence include those coding for an ankyrin repeat containing protein, DsbA, RickA, protease II, OmpA, ScaI, and a putative phosphoethanolamine transferase. The gene coding for the ankyrin repeat containing protein is especially implicated as it is mutated in R. rickettsii strain Iowa, which has attenuated virulence. Presence of numerous copies of the ISRpe1 transposon, likely acquired by lateral transfer from a Cardinium species, are associated with extensive genomic reorganization and deletions. The deletion and mutation of genes possibly involved in loss of virulence have been identified by this genomic comparison. It also illustrates that the introduction of a transposon into the genome can have varied effects; either correlating with an increase in pathogenicity as in Francisella tularensis or a loss of pathogenicity as in R. peacockii and the recombination enabled by multiple transposon copies can cause significant deletions in some genomes while not in others.
Zhu, Dan-Tong; Xia, Wen-Qiang; Rao, Qiong; Liu, Shu-Sheng; Ghanim, Murad; Wang, Xiao-Wei
The whitefly, Bemisia tabaci, harbors the primary symbiont 'Candidatus Portiera aleyrodidarum' and a variety of secondary symbionts. Among these secondary symbionts, Rickettsia is the only one that can be detected both inside and outside the bacteriomes. Infection with Rickettsia has been reported to influence several aspects of the whitefly biology, such as fitness, sex ratio, virus transmission and resistance to pesticides. However, mechanisms underlying these differences remain unclear, largely due to the lack of genomic information of Rickettsia. In this study, we sequenced the genome of two Rickettsia strains isolated from the Middle East Asia Minor 1 (MEAM1) species of the B. tabaci complex in China and Israel. Both Rickettsia genomes were of high coding density and AT-rich, containing more than 1000 coding sequences, much larger than that of the coexisted primary symbiont, Portiera. Moreover, the two Rickettsia strains isolated from China and Israel shared most of the genes with 100% identity and only nine genes showed sequence differences. The phylogenetic analysis using orthologs shared in the genus, inferred the proximity of Rickettsia in MEAM1 and Rickettsia bellii. Functional analysis revealed that Rickettsia was unable to synthesize amino acids required for complementing the whitefly nutrition. Besides, a type IV secretion system and a number of virulence-related genes were detected in the Rickettsia genome. The presence of virulence-related genes might benefit the symbiotic life of the bacteria, and hint on potential effects of Rickettsia on whiteflies. The genome sequences of Rickettsia provided a basis for further understanding the function of Rickettsia in whiteflies. © 2016 Institute of Zoology, Chinese Academy of Sciences.
In Vitro Activities of Telithromycin (HMR 3647) against Rickettsia rickettsii, Rickettsia conorii, Rickettsia africae, Rickettsia typhi, Rickettsia prowazekii, Coxiella burnetii, Bartonella henselae, Bartonella quintana, Bartonella bacilliformis, and Ehrlichia chaffeensis
Rolain, Jean-Marc; Maurin, Max; Bryskier, André; Raoult, Didier
In vitro activities of telithromycin compared to those of erythromycin against Rickettsia spp., Bartonella spp., Coxiella burnetii, and Ehrlichia chaffeensis were determined. Telithromycin was more active than erythromycin against Rickettsia, Bartonella, and Coxiella burnetii, with MICs of 0.5 μg/ml, 0.003 to 0.015 μg/ml, and 1 μg/ml, respectively, but was inactive against Ehrlichia chaffeensis.
Tomassone, L; De Meneghi, D; Adakal, H; Rodighiero, P; Pressi, G; Grego, E
In the framework of cooperation for development projects in Burkina Faso and Ethiopia, we collected ixodid ticks from cattle, small ruminants and camels. We optimized new TaqMan Probe real-time PCR assays to detect Rickettsia aeschlimannii and Rickettsia africae OmpA gene in the collected samples. Rickettsia africae was identified in 75.0% Amblyomma variegatum (95%CI: 56.6-88.5), while R. aeschlimannii in 24.0% Hyalomma truncatum (95%CI: 9.4-45.1) and 50.0% H. rufipes (95%CI: 29.9-70.0) collected from cattle in different provinces throughout Burkina Faso. Ticks from the Libaan zone, Somali Region of Ethiopia, were also infected by R. africae (28.5% prevalence in Amblyomma gemma, 95%CI: 14.7-46.0) and R. aeschlimannii (27.0% H. truncatum, 95%CI: 5.0-62.9; 88.3% H. rufipes, 95%CI: 60.5-99.3). All tested ticks were adults. The developed diagnostic tools were highly sensitive and enabled us to rapidly classify R. aeschlimannii and R. africae, which were identified in Burkina Faso and in the Somali Region of Ethiopia for the first time. Further studies are needed to assess the zoonotic risk and prevalence of infection in local human populations, who have high contact rates with ticks and their animal hosts. Copyright © 2016 Elsevier GmbH. All rights reserved.
Nakao, Ryo; Qiu, Yongjin; Salim, Bashir; Hassan, Shawgi Mohamed; Sugimoto, Chihiro
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.
Gillespie, Joseph J.; Driscoll, Timothy P.; Verhoeve, Victoria I.; Utsuki, Tadanobu; Husseneder, Claudia; Chouljenko, Vladimir N.; Azad, Abdu F.; Macaluso, Kevin R.
Rickettsia felis (Alphaproteobacteria: Rickettsiales) is the causative agent of an emerging flea-borne rickettsiosis with worldwide occurrence. Originally described from the cat flea, Ctenocephalides felis, recent reports have identified R. felis from other flea species, as well as other insects and ticks. This diverse host range for R. felis may indicate an underlying genetic variability associated with host-specific strains. Accordingly, to determine a potential genetic basis for host specialization, we sequenced the genome of R. felis str. LSU-Lb, which is an obligate mutualist of the parthenogenic booklouse Liposcelis bostrychophila (Insecta: Psocoptera). We also sequenced the genome of R. felis str. LSU, the second genome sequence for cat flea-associated strains (cf. R. felis str. URRWXCal2), which are presumably facultative parasites of fleas. Phylogenomics analysis revealed R. felis str. LSU-Lb diverged from the flea-associated strains. Unexpectedly, R. felis str. LSU was found to be divergent from R. felis str. URRWXCal2, despite sharing similar hosts. Although all three R. felis genomes contain the pRF plasmid, R. felis str. LSU-Lb carries an additional unique plasmid, pLbaR (plasmid of L. bostrychophila associated Rickettsia), nearly half of which encodes a unique 23-gene integrative conjugative element. Remarkably, pLbaR also encodes a repeats-in-toxin-like type I secretion system and associated toxin, heretofore unknown from other Rickettsiales genomes, which likely originated from lateral gene transfer with another obligate intracellular parasite of arthropods, Cardinium (Bacteroidetes). Collectively, our study reveals unexpected genomic diversity across three R. felis strains and identifies several diversifying factors that differentiate facultative parasites of fleas from obligate mutualists of booklice. PMID:25477419
Full Text Available Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group and typhus group rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism towards cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and nonpathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and nonpathogenic species of spotted fever group rickettsiae in mammalian cells. The growth of nonpathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of nonpathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the nonpathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review.
Kamani, J; Baneth, G; Apanaskevich, D A; Mumcuoglu, K Y; Harrus, S
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. © 2015 The Royal Entomological Society.
Pilgrim, Jack; Ander, Mats; Garros, Claire; Baylis, Matthew; Hurst, Gregory D D; Siozios, Stefanos
There is increasing interest in the heritable bacteria of invertebrate vectors of disease as they present novel targets for control initiatives. Previous studies on biting midges (Culicoides spp.), known to transmit several RNA viruses of veterinary importance, have revealed infections with the endosymbiotic bacteria, Wolbachia and Cardinium. However, rickettsial symbionts in these vectors are underexplored. Here, we present the genome of a previously uncharacterized Rickettsia endosymbiont from Culicoides newsteadi (RiCNE). This genome presents unique features potentially associated with host invasion and adaptation, including genes for the complete non-oxidative phase of the pentose phosphate pathway, and others predicted to mediate lipopolysaccharides and cell wall modification. Screening of 414 Culicoides individuals from 29 Palearctic or Afrotropical species revealed that Rickettsia represent a widespread but previously overlooked association, reaching high frequencies in midge populations and present in 38% of the species tested. Sequence typing clusters the Rickettsia within the Torix group of the genus, a group known to infect several aquatic and hematophagous taxa. FISH analysis indicated the presence of Rickettsia bacteria in ovary tissue, indicating their maternal inheritance. Given the importance of biting midges as vectors, a key area of future research is to establish the impact of this endosymbiont on vector competence. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.
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
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. Copyright © 2015 Elsevier GmbH. All rights reserved.
Joardar, Vinita; Williams, Kelly P.; Driscoll, Timothy; Hostetler, Jessica B.; Nordberg, Eric; Shukla, Maulik; Walenz, Brian; Hill, Catherine A.; Nene, Vishvanath M.; Azad, Abdu F.; Sobral, Bruno W.; Caler, Elisabet
We present the draft genome for the Rickettsia endosymbiont of Ixodes scapularis (REIS), a symbiont of the deer tick vector of Lyme disease in North America. Among Rickettsia species (Alphaproteobacteria: Rickettsiales), REIS has the largest genome sequenced to date (>2 Mb) and contains 2,309 genes across the chromosome and four plasmids (pREIS1 to pREIS4). The most remarkable finding within the REIS genome is the extraordinary proliferation of mobile genetic elements (MGEs), which contributes to a limited synteny with other Rickettsia genomes. In particular, an integrative conjugative element named RAGE (for Rickettsiales amplified genetic element), previously identified in scrub typhus rickettsiae (Orientia tsutsugamushi) genomes, is present on both the REIS chromosome and plasmids. Unlike the pseudogene-laden RAGEs of O. tsutsugamushi, REIS encodes nine conserved RAGEs that include F-like type IV secretion systems similar to that of the tra genes encoded in the Rickettsia bellii and R. massiliae genomes. An unparalleled abundance of encoded transposases (>650) relative to genome size, together with the RAGEs and other MGEs, comprise ∼35% of the total genome, making REIS one of the most plastic and repetitive bacterial genomes sequenced to date. We present evidence that conserved rickettsial genes associated with an intracellular lifestyle were acquired via MGEs, especially the RAGE, through a continuum of genomic invasions. Robust phylogeny estimation suggests REIS is ancestral to the virulent spotted fever group of rickettsiae. As REIS is not known to invade vertebrate cells and has no known pathogenic effects on I. scapularis, its genome sequence provides insight on the origin of mechanisms of rickettsial pathogenicity. PMID:22056929
Dzelalija, Boris; Punda-Polic, Volga; Medic, Alan; Dobec, Marinko
To review the current state of knowledge concerning rickettsiae and rickettsioses in Croatia and to discuss their implications for travellers. The PubMed database was searched from 1991 to 2015 by combining the words "rickettsia," "rickettsiosis", "travellers" and "Croatia". Since 1969, Croatia appears to be free of epidemic typhus (ET) caused by Rickettsia prowazekii and the last case of Brill-Zinsser disease was recorded in 2008. Mediterranean spotted fever (MSF) caused by Rickettsia conorii is the most frequent human rickettsial infection in Croatia, followed by murine typhus caused by Rickettsia typhi. Human cases of MSF and murine typhus have been predominantly observed along the eastern Adriatic coast from Zadar to Dubrovnik and between Zadar and Split, respectively. Rickettsia akari, etiologic agent of rickettsialpox, was isolated from blood of a patient diagnosed with MSF in Zadar, but no cases of rickettsialpox were reported. Several species of pathogenic (Rickettsia slovaca, Rickettsia aeschlimannii, Ricketsia helvetica, and Ricketsia raoultii) and species of undetermined pathogenicity (Ricketsia hoogstraalii sp. nov.) rickettsiae were identified in ticks collected in different ecological regions of Croatia. A search of the literature revealed no evidence of rickettsial infection in travellers visiting Croatia. Three imported cases of Rickettsia africae were observed in travellers returning from South Africa. Rickettsiae and rickettsial diseases continue to be present in Croatia. As they can be acquired while travelling, physicians should consider rickettsial infection in the differential diagnosis of patients returning from Croatia and presenting with febrile illness. Copyright © 2016 Elsevier Ltd. All rights reserved.
Hanaoka, Nozomu; Matsutani, Minenosuke; Kawabata, Hiroki; Yamamoto, Seigo; Fujita, Hiromi; Sakata, Akiko; Azuma, Yoshinao; Ogawa, Motohiko; Takano, Ai; Watanabe, Haruo; Kishimoto, Toshio; Shirai, Mutsunori; Kurane, Ichiro
We developed a specific and rapid detection system for Rickettsia japonica and R. heilongjiangensis, the causative agents of spotted fever, using a TaqMan minor groove binder probe for a particular open reading frame (ORF) identified by the R. japonica genome project. The target ORF was present only in R. japonica–related strains. PMID:19961684
Genome science is a new type of biology that unites genetics, molecular biology, computational biology and bioinformatics. The availability of the human genome sequence, as well as the genome sequences of several other organisms relevant to health, agriculture and the environment in Africa necessitates the ...
Adebamowo, Sally N; Francis, Veronica; Tambo, Ernest; Diallo, Seybou H; Landouré, Guida; Nembaware, Victoria; Dareng, Eileen; Muhamed, Babu; Odutola, Michael; Akeredolu, Teniola; Nerima, Barbara; Ozumba, Petronilla J; Mbhele, Slee; Ghanash, Anita; Wachinou, Ablo P; Ngomi, Nicholas
There is exponential growth in the interest and implementation of genomics research in Africa. This growth has been facilitated by the Human Hereditary and Health in Africa (H3Africa) initiative, which aims to promote a contemporary research approach to the study of genomics and environmental determinants of common diseases in African populations. The purpose of this article is to describe important challenges affecting genomics research implementation in Africa. The observations, challenges and recommendations presented in this article were obtained through discussions by African scientists at teleconferences and face-to-face meetings, seminars at consortium conferences and in-depth individual discussions. Challenges affecting genomics research implementation in Africa, which are related to limited resources include ill-equipped facilities, poor accessibility to research centers, lack of expertise and an enabling environment for research activities in local hospitals. Challenges related to the research study include delayed funding, extensive procedures and interventions requiring multiple visits, delays setting up research teams and insufficient staff training, language barriers and an underappreciation of cultural norms. While many African countries are struggling to initiate genomics projects, others have set up genomics research facilities that meet international standards. The lessons learned in implementing successful genomics projects in Africa are recommended as strategies to overcome these challenges. These recommendations may guide the development and application of new research programs in low-resource settings.
Adebamowo, Sally N.; Francis, Veronica; Tambo, Ernest; Diallo, Seybou H.; Landouré, Guida; Nembaware, Victoria; Dareng, Eileen; Muhamed, Babu; Odutola, Michael; Akeredolu, Teniola; Nerima, Barbara; Ozumba, Petronilla J.; Mbhele, Slee; Ghanash, Anita; Wachinou, Ablo P.; Ngomi, Nicholas
ABSTRACT Background: There is exponential growth in the interest and implementation of genomics research in Africa. This growth has been facilitated by the Human Hereditary and Health in Africa (H3Africa) initiative, which aims to promote a contemporary research approach to the study of genomics and environmental determinants of common diseases in African populations. Objective: The purpose of this article is to describe important challenges affecting genomics research implementation in Africa. Methods: The observations, challenges and recommendations presented in this article were obtained through discussions by African scientists at teleconferences and face-to-face meetings, seminars at consortium conferences and in-depth individual discussions. Results: Challenges affecting genomics research implementation in Africa, which are related to limited resources include ill-equipped facilities, poor accessibility to research centers, lack of expertise and an enabling environment for research activities in local hospitals. Challenges related to the research study include delayed funding, extensive procedures and interventions requiring multiple visits, delays setting up research teams and insufficient staff training, language barriers and an underappreciation of cultural norms. While many African countries are struggling to initiate genomics projects, others have set up genomics research facilities that meet international standards. Conclusions: The lessons learned in implementing successful genomics projects in Africa are recommended as strategies to overcome these challenges. These recommendations may guide the development and application of new research programs in low-resource settings. PMID:29336236
de Vries, Jantina; Tindana, Paulina; Littler, Katherine; Ramsay, Michèle; Rotimi, Charles; Abayomi, Akin; Mulder, Nicola; Mayosi, Bongani M
Human Heredity and Health in Africa (H3Africa) research seeks to promote fair collaboration between scientists in Africa and those from elsewhere. Here, we outline how concerns over inequality and exploitation led to a policy framework that places a firm focus on African leadership and capacity building as guiding principles for African genomics research. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Joseph J Gillespie
Full Text Available 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.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.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 the acquirement of virulence traits in pathogenic strains, and the
Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O; Choudhury, Ananyo; Ritchie, Graham R S; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N; Young, Elizabeth H; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S
Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.
Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.
Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.
Gallego Llorente, M.; Jones, E. R.; Eriksson, Anders; Siska, V.; Arthur, K. W.; Arthur, J. W.; Curtis, M. C.; Stock, J. T.; Coltorti, M.; Pieruccini, P.; Stretton, S.; Brock, F.; Higham, T.; Park, Y.; Hofreiter, M.; Bradley, D. G.; Bhak, J.; Pinhasi, R.; Manica, A.
Characterizing genetic diversity in Africa is a crucial step for most analyses reconstructing the evolutionary history of anatomically modern humans. However, historic migrations from Eurasia into Africa have affected many contemporary populations, confounding inferences. Here, we present a 12.5×coverage ancient genome of an Ethiopian male ("Mota") who lived approximately 4500 years ago. We use this genome to demonstrate that the Eurasian backflow into Africa came from a population closely related to Early Neolithic farmers, who had colonized Europe 4000 years earlier. The extent of this backflow was much greater than previously reported, reaching all the way to Central, West, and Southern Africa, affecting even populations such as Yoruba and Mbuti, previously thought to be relatively unadmixed, who harbor 6 to 7% Eurasian ancestry.
Gallego Llorente, M.
Characterizing genetic diversity in Africa is a crucial step for most analyses reconstructing the evolutionary history of anatomically modern humans. However, historic migrations from Eurasia into Africa have affected many contemporary populations, confounding inferences. Here, we present a 12.5×coverage ancient genome of an Ethiopian male ("Mota") who lived approximately 4500 years ago. We use this genome to demonstrate that the Eurasian backflow into Africa came from a population closely related to Early Neolithic farmers, who had colonized Europe 4000 years earlier. The extent of this backflow was much greater than previously reported, reaching all the way to Central, West, and Southern Africa, affecting even populations such as Yoruba and Mbuti, previously thought to be relatively unadmixed, who harbor 6 to 7% Eurasian ancestry.
Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.
Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterisation of African genetic diversity is needed. The African Genome Variation Project (AGVP) provides a resource to help design, implement and interpret genomic studies in sub-Saharan Africa (SSA) and worldwide. The AGVP represents dense genotypes from 1,481 and whole genome sequences (WGS) from 320 individuals across SSA. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across SSA. We identify new loci under selection, including for malaria and hypertension. We show that modern imputation panels can identify association signals at highly differentiated loci across populations in SSA. Using WGS, we show further improvement in imputation accuracy supporting efforts for large-scale sequencing of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa, showing for the first time that such designs are feasible. PMID:25470054
Chisu, Valentina; Leulmi, Hamza; Masala, Giovanna; Piredda, Mariano; Foxi, Cipriano; Parola, Philippe
Tick-borne diseases represent a large proportion of infectious diseases that have become a world health concern. The presence of Rickettsia spp. was evaluated by standard PCR and sequencing in 123 ticks collected from several mammals and vegetation in Sardinia, Italy. This study provides the first evidence of the presence of Rickettsia hoogstralii in Haemaphysalis punctata and Haemaphysalis sulcata ticks from mouflon and Rickettsia helvetica in Ixodes festai ticks from hedgehog. In addition, Rickettsia massiliae, Rickettsia slovaca and Rickettsia aeschlimannii were detected in Rhipicephalus sanguineus, Dermacentor marginatus and Hyalomma marginatum marginatum ticks from foxes, swine, wild boars, and mouflon. The data presented here increase our knowledge of tick-borne diseases in Sardinia and provide a useful contribution toward understanding their epidemiology. Copyright © 2016 Elsevier GmbH. All rights reserved.
Anstead, Clare A.
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.” PMID:24077705
US Agency for International Development — This dataset contains the complete mitochondrial genome of Anoplocnemis curvipes F. (Coreinea, Coreidae, Heteroptera), a pest of fresh cowpea pods. To get to the...
Braun, Lundy; Hammonds, Evelynn
Much of the recent debate over race, genetics, and health has focused on the extent to which typological notions of race have biological meaning. Less attention, however, has been paid to the assumptions about the nature of "populations" that both inform contemporary biological and medical research and that underlie the concept of race. Focusing specifically on Africa in the 1930s and 1940s, this paper explores the history of how fluid societies were transformed into bounded units amenable to scientific analysis. In the so-called "Golden Age of Ethnography," university-trained social anthropologists, primarily from Britain and South Africa, took to the field to systematically study, organize, and order the world's diverse peoples. Intent on creating a scientific methodology of neutral observation, they replaced amateur travelers, traders, colonial administrators, and missionaries as authoritative knowledge producers about the customs, beliefs, and languages of indigenous peoples. At the same time, linguists were engaged in unifying African languages and mapping language onto primordial "tribal" territories. We argue that the notion of populations or "tribes" as discrete units suitable for scientific sampling and classification emerged in the 1930s and 1940s with the ethnographic turn in social anthropology and the professionalization and institutionalization of linguistics in Western and South African universities. Once named and entered into international atlases and databases by anthropologists in the U.S., the existence of populations as bounded entities became self-evident, thus setting the stage for their use in large-scale population genetic studies and the contemporary reinvigoration of broad claims of difference based on population identification.
Adebamowo, Sally N; Tekola-Ayele, Fasil; Adeyemo, Adebowale A; Rotimi, Charles N
Sub-Saharan Africa (SSA) is experiencing a growing burden of cardiometabolic disorders, including diabetes, dyslipidemia, hypertension, obesity, coronary heart disease, and stroke. The increasing trends are expected to accelerate as SSA continues to experience economic progress, population growth, and the shift from communicable to noncommunicable diseases. These complex disorders are caused by multiple, potentially interacting, environmental, and genetic factors. While considerable progress has been made in the identification of the sociocultural, demographic, and lifestyle risk factors for cardiometabolic disorders, many genetic factors that underlie individual susceptibility to these diseases remain largely unknown. Although progress in genomic technologies has allowed for systematic characterization of genome-wide genetic diversity in health and disease in European and Asian ancestry populations, conduct of genetic studies in SSA has been underwhelming until recently. Here, we summarize recent understanding of the body of knowledge and highlight research opportunities on the genomics of cardiometabolic disorders in SSA. Published by S. Karger AG, Basel.
de Vries, Jantina; Pepper, Michael
Scientific interest in genomics in Africa is on the rise with a number of funding initiatives aimed specifically at supporting research in this area. Genomics research on material of African origin raises a number of important ethical issues. A prominent concern relates to sample export, which is increasingly seen by researchers and ethics committees across the continent as being problematic. The concept of genomic sovereignty proposes that unique patterns of genomic variation can be found in human populations, and that these are commercially, scientifically or symbolically valuable and in need of protection against exploitation. Although it is appealing as a response to increasing concerns regarding sample export, there are a number of important conceptual problems relating to the term. It is not clear, for instance, whether it is appropriate that ownership over human genomic samples should rest with national governments. Furthermore, ethnic groups in Africa are frequently spread across multiple nation states, and protection offered in one state may not prevent researchers from accessing the same group elsewhere. Lastly, scientific evidence suggests that the assumption that genomic data is unique for population groups is false. Although the frequency with which particular variants are found can differ between groups, such genes or variants per se are not unique to any population group. In this paper, the authors describe these concerns in detail and argue that the concept of genomic sovereignty alone may not be adequate to protect the genetic resources of people of African descent.
Socolovschi, Cristina; Pages, Frédéric; Ndiath, Mamadou O.; Ratmanov, Pavel; Raoult, Didier
Background There is higher rate of R. felis infection among febrile patients than in healthy people in Sub-Saharan Africa, predominantly in the rainy season. Mosquitoes possess a high vectorial capacity and, because of their abundance and aggressiveness, likely play a role in rickettsial epidemiology. Methodology/Principal Findings Quantitative and traditional PCR assays specific for Rickettsia genes detected rickettsial DNA in 13 of 848 (1.5%) Anopheles mosquitoes collected from Côte d’Ivoire, Gabon, and Senegal. R. felis was detected in one An. gambiae molecular form S mosquito collected from Kahin, Côte d’Ivoire (1/77, 1.3%). Additionally, a new Rickettsia genotype was detected in five An. gambiae molecular form S mosquitoes collected from Côte d’Ivoire (5/77, 6.5%) and one mosquito from Libreville, Gabon (1/88, 1.1%), as well as six An. melas (6/67, 9%) mosquitoes collected from Port Gentil, Gabon. A sequence analysis of the gltA, ompB, ompA and sca4 genes indicated that this new Rickettsia sp. is closely related to R. felis. No rickettsial DNA was detected from An. funestus, An. arabiensis, or An. gambiae molecular form M mosquitoes. Additionally, a BLAST analysis of the gltA sequence from the new Rickettsia sp. resulted in a 99.71% sequence similarity to a species (JQ674485) previously detected in a blood sample of a Senegalese patient with a fever from the Bandafassi village, Kedougou region. Conclusion R. felis was detected for the first time in An. gambiae molecular form S, which represents the major African malaria vector. The discovery of R. felis, as well as a new Rickettsia species, in mosquitoes raises new issues with respect to African rickettsial epidemiology that need to be investigated, such as bacterial isolation, the degree of the vectorial capacity of mosquitoes, the animal reservoirs, and human pathogenicity. PMID:23118963
Singer Peter A
Full Text Available Abstract Background Africa in the twenty-first century is faced with a heavy burden of disease, combined with ill-equipped medical systems and underdeveloped technological capacity. A major challenge for the international community is to bring scientific and technological advances like genomics to bear on the health priorities of poorer countries. The New Partnership for Africa's Development has identified science and technology as a key platform for Africa's renewal. Recognizing the timeliness of this issue, the African Centre for Technology Studies and the University of Toronto Joint Centre for Bioethics co-organized a course on Genomics and Public Health Policy in Nairobi, Kenya, the first of a series of similar courses to take place in the developing world. This article presents the findings and recommendations that emerged from this process, recommendations which suggest that a regional approach to developing sound science and technology policies is the key to harnessing genome-related biotechnology to improve health and contribute to human development in Africa. Methods The objectives of the course were to familiarize participants with the current status and implications of genomics for health in Africa; to provide frameworks for analyzing and debating the policy and ethical questions; and to begin developing a network across different sectors by sharing perspectives and building relationships. To achieve these goals the course brought together a diverse group of stakeholders from academic research centres, the media, non-governmental, voluntary and legal organizations to stimulate multi-sectoral debate around issues of policy. Topics included scientific advances in genomics innovation systems and business models, international regulatory frameworks, as well as ethical and legal issues. Results Seven main recommendations emerged: establish a network for sustained dialogue among participants; identify champions among politicians; use the
Full Text Available Some of the most significant breakthroughs in the biological sciences this century will emerge from the development of next generation sequencing technologies. The ease of availability of DNA sequence made possible through these new technologies has given researchers opportunities to study organisms in a manner that was not possible with Sanger sequencing. Scientists will, therefore, need to embrace genomics, as well as develop and nurture the human capacity to sequence genomes and utilise the ’tsunami‘ of data that emerge from genome sequencing. In response to these challenges, we sequenced the genome of Fusarium circinatum, a fungal pathogen of pine that causes pitch canker, a disease of great concern to the South African forestry industry. The sequencing work was conducted in South Africa, making F. circinatum the first eukaryotic organism for which the complete genome has been sequenced locally. Here we report on the process that was followed to sequence, assemble and perform a preliminary characterisation of the genome. Furthermore, details of the computer annotation and manual curation of this genome are presented. The F. circinatum genome was found to be nearly 44 million bases in size, which is similar to that of four other Fusarium genomes that have been sequenced elsewhere. The genome contains just over 15 000 open reading frames, which is less than that of the related species, Fusarium oxysporum, but more than that for Fusarium verticillioides. Amongst the various putative gene clusters identified in F. circinatum, those encoding the secondary metabolites fumosin and fusarin appeared to harbour evidence of gene translocation. It is anticipated that similar comparisons of other loci will provide insights into the genetic basis for pathogenicity of the pitch canker pathogen. Perhaps more importantly, this project has engaged a relatively large group of scientists
de Barros Lopes, Lívia; Guterres, Alexandro; Rozental, Tatiana; Carvalho de Oliveira, Renata; Mares-Guia, Maria Angélica; Fernandes, Jorlan; Figueredo, José Ferreira; Anschau, Inês; de Jesus, Sebastião; V Almeida, Ana Beatriz M; Cristina da Silva, Valéria; Gomes de Melo Via, Alba Valéria; Bonvicino, Cibele Rodrigues; D'Andrea, Paulo Sérgio; Barreira, Jairo Dias; Sampaio de Lemos, Elba Regina
The purpose of this study was to identify the presence of rickettsia and hantavirus in wild rodents and arthropods in response to an outbreak of acute unidentified febrile illness among Indians in the Halataikwa Indian Reserve, northwest of the Mato Grosso state, in the Brazilian Amazon. Where previously surveillance data showed serologic evidence of rickettsia and hantavirus human infection. The arthropods were collected from the healthy Indian population and by flagging vegetation in grassland or woodland along the peridomestic environment of the Indian reserve. Wild rodents were live-trapped in an area bordering the reserve limits, due the impossibility of capturing wild animals in the Indian reserve. The wild rodents were identified based on external and cranial morphology and karyotype. DNA was extracted from spleen or liver samples of rodents and from invertebrate (tick and louse) pools, and the molecular characterization of the rickettsia was through PCR and DNA sequencing of fragments of two rickettsial genes (gltA and ompA). In relation to hantavirus, rodent serum samples were serologically screened by IgG ELISA using the Araraquara-N antigen and total RNA was extracted from lung samples of IgG-positive rodents. The amplification of the complete S segment was performed. A total of 153 wild rodents, 121 louse, and 36 tick specimens were collected in 2010. Laguna Negra hantavirus was identified in Calomys callidus rodents and Rickettsia bellii, Rickettsia amblyommii were identified in Amblyomma cajennense ticks. Zoonotic diseases such as HCPS and spotted fever rickettsiosis are a public health threat and should be considered in outbreaks and acute febrile illnesses among Indian populations. The presence of the genome of rickettsias and hantavirus in animals in this Indian reserve reinforces the need to include these infectious agents in outbreak investigations of febrile cases in Indian populations.
Papa, Anna; Xanthopoulou, Kyriaki; Kotriotsiou, Tzimoula; Papaioakim, Miltiadis; Sotiraki, Smaragda; Chaligiannis, Ilias; Maltezos, Efstratios
Ticks serve as vectors and reservoirs for a variety of bacterial, viral and protozoan pathogens affecting humans and animals. Unusual increased tick aggressiveness was observed in 2008-2009 in northeastern Greece. The aim of the study was to check ticks removed from persons during 2009 for infection with Rickettsia species. A total of 159 ticks were removed from 147 persons who sought medical advice in a hospital. Tick identification was performed morphologically using taxonomic keys. DNA was extracted from each individual tick and a PCR assay targeting the rickettsial outer membrane protein A gene of Rickettsia spp. was applied. Most of the adult ticks (132/153, 86.3%) were Rhipicephalus sanguineus. Rickettsiae were detected in 23 of the 153 (15.0%) adult ticks. Five Rickettsiae species were identified: R. aeschlimannii, R. africae (n=6), R. massilae (4), R. monacensis (1), and Candidatus R. barbariae (1). To our knowledge, this is the first report of R. africae, R. monacensis, and Candidatus R. barbariae in Greece. Several Rickettsia species were identified in ticks removed from humans in Greece, including those that are prevalent in northern and southern latitudes. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
Ogata, H; Audic, S; Barbe, V; Artiguenave, F; Fournier, P E; Raoult, D; Claverie, J M
Rickettsia conorii, the aetiological agent of Mediterranean spotted fever, is an intracellular bacterium transmitted by ticks. Preliminary analyses of the nearly complete genome sequence of R. conorii have revealed 44 occurrences of a previously undescribed palindromic repeat (150 base pairs long) throughout the genome. Unexpectedly, this repeat was found inserted in-frame within 19 different R. conorii open reading frames likely to encode functional proteins. We found the same repeat in proteins of other Rickettsia species. The finding of a mobile element inserted in many unrelated genes suggests the potential role of selfish DNA in the creation of new protein sequences.
Full Text Available BACKGROUND: Rickettsia conorii, the causative agent of the Mediterranean spotted fever, is transmitted to humans by the bite of infected ticks Rhipicephalus sanguineus. The skin thus constitutes an important barrier for the entry and propagation of R. conorii. Given this, analysis of the survival strategies used by the bacterium within infected skin is critical for our understanding of rickettsiosis. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the first genome-wide analysis of R. conorii gene expression from infected human skin biopsies. Our data showed that R. conorii exhibited a striking transcript signature that is remarkably conserved across patients, regardless of genotype. The expression profiles obtained using custom Agilent microarrays were validated by quantitative RT-PCR. Within eschars, the amount of detected R. conorii transcripts was of 55%, this value being of 74% for bacteria grown in Vero cells. In such infected host tissues, approximately 15% (n = 211 of the total predicted R. conorii ORFs appeared differentially expressed compared to bacteria grown in standard laboratory conditions. These genes are mostly down-regulated and encode proteins essential for bacterial replication. Some of the strategies displayed by rickettsiae to overcome the host defense barriers, thus avoiding killing, were also pointed out. The observed up-regulation of rickettsial genes associated with DNA repair is likely to correspond to a DNA-damaging agent enriched environment generated by the host cells to eradicate the pathogens. Survival of R. conorii within eschars also involves adaptation to osmotic stress, changes in cell surface proteins and up-regulation of some virulence factors. Interestingly, in contrast to down-regulated transcripts, we noticed that up-regulated ones rather exhibit a small nucleotide size, most of them being exclusive for the spotted fever group rickettsiae. CONCLUSION/SIGNIFICANCE: Because eschar is a site for rickettsial
Izzard, Leonard; Graves, Stephen; Cox, Erika; Fenwick, Stan; Unsworth, Nathan; Stenos, John
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.
Pornwiroon, Walairat; Bourchookarn, Apichai; Paddock, Christopher D; Macaluso, Kevin R
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. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.
Chitimia-Dobler, Lidia; Dobler, Gerhard; Schaper, Sabine; Küpper, Thomas; Kattner, Simone; Wölfel, Silke
Ticks are important vectors for Rickettsia spp. of the spotted fever group all around the world. Rickettsia conorii is the etiological agent of boutonneuse fever in the Mediterranean region and Africa. Tick identification was based on morphological features and further characterized using the 16S rRNA gene. The ticks were individually tested using pan-Rickettsia real-time-PCR for screening, and 23S-5S intergenic spacer region, 16S rDNA, gltA, sca4, ompB, and ompA genes were used to analyze the Rickettsia positive samples. Rickettsia conorii ssp. caspia was detected in tick collected in Zambia for the first time, thus demonstrating the possibility of the occurrence of human disease, namely Astrakhan fever, due to this Rickettsia ssp. in this region of Africa. The prevalence of R. conorii ssp. caspia was 0.06% (one positive tick out of 1465 tested ticks) and 0.07% (one positive tick out of 1254 tested Rh. sanguineus).
Weck, Bárbara; Dall'Agnol, Bruno; Souza, Ugo; Webster, Anelise; Stenzel, Bárbara; Klafke, Guilherme; Martins, João Ricardo; Reck, José
Spotted fever is an acute febrile illness, which is considered severely underreported and misdiagnosed in the Brazilian Pampa, caused by tick-borne Rickettsiae. Here, we report an eco-epidemiological investigation of Rickettsia spp. in ticks from a spotted fever focus in Toropi, southern Brazil. Ticks were collected from capybara carcasses and processed individually to obtain genomic DNA. Rickettsia was investigated using PCR that amplified the rickettsial fragments of the gltA, ompA and htrA genes. DNA from Rickettsia parkeri was found in four of 14 Amblyomma dubitatum ticks collected from capybara carcasses in Toropi and the nearby municipality of Quevedos. We also tested 210A. dubitatum ticks obtained from road-killed capybaras of other localities from the Pampa biome; none of them were positive for Rickettsiae. Thus, in Rio Grande do Sul, two Rickettsia species can be potentially associated to spotted fever: Rickettsia sp. strain Atlantic Rainforest, associated with Amblyomma ovale ticks in the Atlantic Rainforest biome, and R. parkeri, associated both with Amblyomma tigrinum and A. dubitatum ticks in the Pampa biome. Our results reinforce that R. parkeri may be the agent associated with spotted fever in the Brazilian Pampa. Copyright © 2017 Elsevier B.V. All rights reserved.
Full Text Available Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group (SFG rickettsiae. Although Spotted Fever is prevalent in the Middle East, no reports for the presence of tick-borne pathogens are available or any studies on the epidemiology of this disease in the West Bank. We aimed to identify the circulating hard tick vectors and genetically characterize SFG Rickettsia species in ixodid ticks from the West Bank-Palestinian territories.A total of 1,123 ixodid ticks belonging to eight species (Haemaphysalis parva, Haemaphysalis adleri, Rhipicephalus turanicus, Rhipicephalus sanguineus, Rhipicephalus bursa, Hyalomma dromedarii, Hyalomma aegyptium and Hyalomma impeltatum were collected from goats, sheep, camels, dogs, a wolf, a horse and a tortoise in different localities throughout the West Bank during the period of January-April, 2014. A total of 867 ticks were screened for the presence of rickettsiae by PCR targeting a partial sequence of the ompA gene followed by sequence analysis. Two additional genes, 17 kDa and 16SrRNA were also targeted for further characterization of the detected Rickettsia species. Rickettsial DNA was detected in 148 out of the 867 (17% tested ticks. The infection rates in Rh. turanicus, Rh. sanguineus, H. adleri, H. parva, H. dromedarii, and H. impeltatum ticks were 41.7, 11.6, 16.7, 16.2, 11.8 and 20%, respectively. None of the ticks, belonging to the species Rh. bursa and H. aegyptium, were infected. Four SFG rickettsiae were identified: Rickettsia massiliae, Rickettsia africae, Candidatus Rickettsia barbariae and Candidatus Rickettsia goldwasserii.The results of this study demonstrate the geographic distribution of SFG rickettsiae and clearly indicate the presence of at least four of them in collected ticks. Palestinian clinicians should be aware of emerging tick-borne diseases in the West Bank, particularly infections due to R. massiliae and R. africae.
Driscoll, Timothy P; Verhoeve, Victoria I; Guillotte, Mark L; Lehman, Stephanie S; Rennoll, Sherri A; Beier-Sexton, Magda; Rahman, M Sayeedur; Azad, Abdu F; Gillespie, Joseph J
Reductive genome evolution has purged many metabolic pathways from obligate intracellular Rickettsia ( Alphaproteobacteria ; Rickettsiaceae ). While some aspects of host-dependent rickettsial metabolism have been characterized, the array of host-acquired metabolites and their cognate transporters remains unknown. This dearth of information has thwarted efforts to obtain an axenic Rickettsia culture, a major impediment to conventional genetic approaches. Using phylogenomics and computational pathway analysis, we reconstructed the Rickettsia metabolic and transport network, identifying 51 host-acquired metabolites (only 21 previously characterized) needed to compensate for degraded biosynthesis pathways. In the absence of glycolysis and the pentose phosphate pathway, cell envelope glycoconjugates are synthesized from three imported host sugars, with a range of additional host-acquired metabolites fueling the tricarboxylic acid cycle. Fatty acid and glycerophospholipid pathways also initiate from host precursors, and import of both isoprenes and terpenoids is required for the synthesis of ubiquinone and the lipid carrier of lipid I and O-antigen. Unlike metabolite-provisioning bacterial symbionts of arthropods, rickettsiae cannot synthesize B vitamins or most other cofactors, accentuating their parasitic nature. Six biosynthesis pathways contain holes (missing enzymes); similar patterns in taxonomically diverse bacteria suggest alternative enzymes that await discovery. A paucity of characterized and predicted transporters emphasizes the knowledge gap concerning how rickettsiae import host metabolites, some of which are large and not known to be transported by bacteria. Collectively, our reconstructed metabolic network offers clues to how rickettsiae hijack host metabolic pathways. This blueprint for growth determinants is an important step toward the design of axenic media to rescue rickettsiae from the eukaryotic cell. IMPORTANCE A hallmark of obligate intracellular
Thomas K. Karikari
Full Text Available Bioinformatics and genome science (BGS are gradually gaining roots in Africa, contributing to studies that are leading to improved understanding of health, disease, agriculture and food security. While a few African countries have established foundations for research and training in these areas, BGS appear to be limited to only a few institutions in specific African countries. However, improving the disciplines in Africa will require pragmatic efforts to expand training and research partnerships to scientists in yet-unreached institutions. Here, we discuss the need to expand BGS programmes in Africa, and propose mechanisms to do so.
Koka, Hellen; Sang, Rosemary; Kutima, Helen Lydia; Musila, Lillian
In this study, ticks from pastoral communities in Kenya were tested for Rickettsia spp. infections in geographical regions where the presence of tick-borne arboviruses had previously been reported. Rickettsial and arbovirus infections have similar clinical features which makes differential diagnosis challenging when both diseases occur. The tick samples were tested for Rickettsia spp. by conventional PCR using three primer sets targeting the gltA, ompA, and ompB genes followed by amplicon sequencing. Of the tick pools screened, 25% (95/380) were positive for Rickettsia spp. DNA using the gltA primer set. Of the tick-positive pools, 60% were ticks collected from camels. Rickettsia aeschlimannii and R. africae were the main Rickettsia spp. detected in the tick pools sequenced. The findings of this study indicate that multiple Rickettsia species are circulating in ticks from pastoral communities in Kenya and could contribute to the etiology of febrile illness in these areas. Diagnosis and treatment of rickettsial infections should be a public health priority in these regions. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Joseph J Gillespie
Full Text Available BACKGROUND: Completed genome sequences are rapidly increasing for Rickettsia, obligate intracellular alpha-proteobacteria responsible for various human diseases, including epidemic typhus and Rocky Mountain spotted fever. In light of phylogeny, the establishment of orthologous groups (OGs of open reading frames (ORFs will distinguish the core rickettsial genes and other group specific genes (class 1 OGs or C1OGs from those distributed indiscriminately throughout the rickettsial tree (class 2 OG or C2OGs. METHODOLOGY/PRINCIPAL FINDINGS: We present 1823 representative (no gene duplications and 259 non-representative (at least one gene duplication rickettsial OGs. While the highly reductive (approximately 1.2 MB Rickettsia genomes range in predicted ORFs from 872 to 1512, a core of 752 OGs was identified, depicting the essential Rickettsia genes. Unsurprisingly, this core lacks many metabolic genes, reflecting the dependence on host resources for growth and survival. Additionally, we bolster our recent reclassification of Rickettsia by identifying OGs that define the AG (ancestral group, TG (typhus group, TRG (transitional group, and SFG (spotted fever group rickettsiae. OGs for insect-associated species, tick-associated species and species that harbor plasmids were also predicted. Through superimposition of all OGs over robust phylogeny estimation, we discern between C1OGs and C2OGs, the latter depicting genes either decaying from the conserved C1OGs or acquired laterally. Finally, scrutiny of non-representative OGs revealed high levels of split genes versus gene duplications, with both phenomena confounding gene orthology assignment. Interestingly, non-representative OGs, as well as OGs comprised of several gene families typically involved in microbial pathogenicity and/or the acquisition of virulence factors, fall predominantly within C2OG distributions. CONCLUSION/SIGNIFICANCE: Collectively, we determined the relative conservation and
Background A few billion birds migrate annually between their breeding grounds in Europe and their wintering grounds in Africa. Many bird species are tick-infested, and as a result of their innate migratory behavior, they contribute significantly to the geographic distribution of pathogens, including spotted fever rickettsiae. The aim of the present study was to characterize, in samples from two consecutive years, the potential role of migrant birds captured in Europe as disseminators of Rickettsia-infected ticks. Methods Ticks were collected from a total of 14,789 birds during their seasonal migration northwards in spring 2009 and 2010 at bird observatories on two Mediterranean islands: Capri and Antikythira. All ticks were subjected to RNA extraction followed by cDNA synthesis and individually assayed with a real-time PCR targeting the citrate synthase (gltA) gene. For species identification of Rickettsia, multiple genes were sequenced. Results Three hundred and ninety-eight (2.7%) of all captured birds were tick-infested; some birds carried more than one tick. A total number of 734 ticks were analysed of which 353 ± 1 (48%) were Rickettsia-positive; 96% were infected with Rickettsia aeschlimannii and 4% with Rickettsia africae or unidentified Rickettsia species. The predominant tick taxon, Hyalomma marginatum sensu lato constituted 90% (n = 658) of the ticks collected. The remaining ticks were Ixodes frontalis, Amblyomma sp., Haemaphysalis sp., Rhipicephalus sp. and unidentified ixodids. Most ticks were nymphs (66%) followed by larvae (27%) and adult female ticks (0.5%). The majority (65%) of ticks was engorged and nearly all ticks contained visible blood. Conclusions Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations. The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination. PMID:25011617
Tassi, Francesca; Ghirotto, Silvia; Mezzavilla, Massimo; Vilaça, Sibelle Torres; De Santi, Lisa; Barbujani, Guido
Anthropological and genetic data agree in indicating the African continent as the main place of origin for anatomically modern humans. However, it is unclear whether early modern humans left Africa through a single, major process, dispersing simultaneously over Asia and Europe, or in two main waves, first through the Arab Peninsula into southern Asia and Oceania, and later through a northern route crossing the Levant. Here, we show that accurate genomic estimates of the divergence times between European and African populations are more recent than those between Australo-Melanesia and Africa and incompatible with the effects of a single dispersal. This difference cannot possibly be accounted for by the effects of either hybridization with archaic human forms in Australo-Melanesia or back migration from Europe into Africa. Furthermore, in several populations of Asia we found evidence for relatively recent genetic admixture events, which could have obscured the signatures of the earliest processes. We conclude that the hypothesis of a single major human dispersal from Africa appears hardly compatible with the observed historical and geographical patterns of genome diversity and that Australo-Melanesian populations seem still to retain a genomic signature of a more ancient divergence from Africa.
Shpynov, Stanislav; Fournier, Pierre-Edouard; Rudakov, Nikolay; Tankibaev, Marat; Tarasevich, Irina; Raoult, Didier
Using PCR, we screened 411 ticks from four genera collected in Russia and Kazakhstan for the presence of rickettsiae and ehrlichiae. In Russia, we detected “Rickettsia heilongjiangensis,” Rickettsia sp. strain RpA4, and Ehrlichia muris. In Kazakhstan, we detected Rickettsia sp. strain RpA4 and a rickettsia closely related to Rickettsia aeschlimannii. These agents should be considered in a differential diagnosis of tick-borne infections in these areas.
Fernández de Mera, Isabel G; Blanda, Valeria; Torina, Alessandra; Dabaja, Mayssaa Fawaz; El Romeh, Ali; Cabezas-Cruz, Alejandro; de la Fuente, José
Tick-borne diseases have become a world health concern, emerging with increasing incidence in recent decades. Spotted fever group (SFG) rickettsiae are tick-borne pathogens recognized as important agents of human tick-borne diseases worldwide. In this study, 88 adult ticks from the species Hyalomma anatolicum, Rhipicephalus annulatus, Rh. bursa, Rh. sanguineus sensu lato, and Rh. turanicus, were collected from farm ruminants in Lebanon, and SFG rickettsiae were molecularly identified and characterized in these ticks. The screening showed a prevalence of 68% for Rickettsia spp., including the species R. aeschlimannii, R. africae, R. massiliae and Candidatus R. barbariae, the latter considered an emerging member of the SFG rickettsiae. These findings contribute to a better knowledge of the distribution of these pathogens and demonstrate that SFG rickettsiae with public health relevance are found in ticks collected in Lebanon, where the widespread distribution of tick vectors and possible livestock animal hosts in contact with humans may favor transmission to humans. Few reports exist for some of the tick species identified here as being infected with SFG Rickettsia. Some of these tick species are proven vectors of the hosted rickettsiae, although this information is unknown for other of these species. Therefore, these results suggested further investigation on the vector competence of the tick species with unknown role in transmission of some of the pathogens identified in this study. Copyright © 2017 Elsevier GmbH. All rights reserved.
Bodnar, James; Mortazavi, Bobak; Laurent, Timothy; Deason, Jeff; Thephavongsa, Khanhkeo; Zhong, Jianmin
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. PMID:26650541
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.
Human Infection with Rickettsia felis, Kenya Allen L. Richards, Ju Jiang, Sylvia Omulo, Ryan Dare, Khalif Abdirah~a~, P:bdile Ali, Shanaaz K...infection with obligate intracellular rickettsiae , which are transmitted to humans by arthropod vectors (e.g., lice, fleas, ticks, and mites... Rickettsiae are associated with arthropods for a least a part of their life cycle and are passed to other arthropods by transovarial transmission or
Riley, Sean P; Macaluso, Kevin R; Martinez, Juan J
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. PMID:26528784
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
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. Copyright © 2016. Published by Elsevier GmbH.
Brenna M Henn
Full Text Available North African populations are distinct from sub-Saharan Africans based on cultural, linguistic, and phenotypic attributes; however, the time and the extent of genetic divergence between populations north and south of the Sahara remain poorly understood. Here, we interrogate the multilayered history of North Africa by characterizing the effect of hypothesized migrations from the Near East, Europe, and sub-Saharan Africa on current genetic diversity. We present dense, genome-wide SNP genotyping array data (730,000 sites from seven North African populations, spanning from Egypt to Morocco, and one Spanish population. We identify a gradient of likely autochthonous Maghrebi ancestry that increases from east to west across northern Africa; this ancestry is likely derived from "back-to-Africa" gene flow more than 12,000 years ago (ya, prior to the Holocene. The indigenous North African ancestry is more frequent in populations with historical Berber ethnicity. In most North African populations we also see substantial shared ancestry with the Near East, and to a lesser extent sub-Saharan Africa and Europe. To estimate the time of migration from sub-Saharan populations into North Africa, we implement a maximum likelihood dating method based on the distribution of migrant tracts. In order to first identify migrant tracts, we assign local ancestry to haplotypes using a novel, principal component-based analysis of three ancestral populations. We estimate that a migration of western African origin into Morocco began about 40 generations ago (approximately 1,200 ya; a migration of individuals with Nilotic ancestry into Egypt occurred about 25 generations ago (approximately 750 ya. Our genomic data reveal an extraordinarily complex history of migrations, involving at least five ancestral populations, into North Africa.
Gillespie, Joseph J.; Kaur, Simran J.; Rahman, M. Sayeedur; Rennoll-Bankert, Kristen; Sears, Khandra T.; Beier-Sexton, Magda; Azad, Abdu F.
The genus Rickettsia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) is comprised of obligate intracellular parasites, with virulent species of interest both as causes of emerging infectious diseases and for their potential deployment as bioterrorism agents. Currently, there are no effective commercially available vaccines, with treatment limited primarily to tetracycline antibiotics, although others (e.g. josamycin, ciprofloxacin, chloramphenicol, and azithromycin) are also effective. Much of the recent research geared toward understanding mechanisms underlying rickettsial pathogenicity has centered on characterization of secreted proteins that directly engage eukaryotic cells. Herein, we review all aspects of the Rickettsia secretome, including six secretion systems, 19 characterized secretory proteins, and potential moonlighting proteins identified on surfaces of multiple Rickettsia species. Employing bioinformatics and phylogenomics, we present novel structural and functional insight on each secretion system. Unexpectedly, our investigation revealed that the majority of characterized secretory proteins have not been assigned to their cognate secretion pathways. Furthermore, for most secretion pathways, the requisite signal sequences mediating translocation are poorly understood. As a blueprint for all known routes of protein translocation into host cells, this resource will assist research aimed at uniting characterized secreted proteins with their apposite secretion pathways. Furthermore, our work will help in the identification of novel secreted proteins involved in rickettsial ‘life on the inside’. PMID:25168200
Loyola, Steev; Flores-Mendoza, Carmen; Torre, Armando; Kocher, Claudine; Melendrez, Melanie; Luce-Fedrow, Alison; Maina, Alice N; Richards, Allen L; Leguia, Mariana
While studying rickettsial infections in Peru, we detected Rickettsia asembonensis in fleas from domestic animals. We characterized 5 complete genomic regions (17kDa, gltA, ompA, ompB, and sca4) and conducted multilocus sequence typing and phylogenetic analyses. The molecular isolate from Peru is distinct from the original R. asembonensis strain from Kenya.
Full Text Available The geostrategic location of North Africa as a crossroad between three continents and as a stepping-stone outside Africa has evoked anthropological and genetic interest in this region. Numerous studies have described the genetic landscape of the human population in North Africa employing paternal, maternal, and biparental molecular markers. However, information from these markers which have different inheritance patterns has been mostly assessed independently, resulting in an incomplete description of the region. In this study, we analyze uniparental and genome-wide markers examining similarities or contrasts in the results and consequently provide a comprehensive description of the evolutionary history of North Africa populations. Our results show that both males and females in North Africa underwent a similar admixture history with slight differences in the proportions of admixture components. Consequently, genome-wide diversity show similar patterns with admixture tests suggesting North Africans are a mixture of ancestral populations related to current Africans and Eurasians with more affinity towards the out-of-Africa populations than to sub-Saharan Africans. We estimate from the paternal lineages that most North Africans emerged ∼15,000 years ago during the last glacial warming and that population splits started after the desiccation of the Sahara. Although most North Africans share a common admixture history, the Tunisian Berbers show long periods of genetic isolation and appear to have diverged from surrounding populations without subsequent mixture. On the other hand, continuous gene flow from the Middle East made Egyptians genetically closer to Eurasians than to other North Africans. We show that genetic diversity of today's North Africans mostly captures patterns from migrations post Last Glacial Maximum and therefore may be insufficient to inform on the initial population of the region during the Middle Paleolithic period.
Fadhlaoui-Zid, Karima; Haber, Marc; Martínez-Cruz, Begoña; Zalloua, Pierre; Benammar Elgaaied, Amel; Comas, David
The geostrategic location of North Africa as a crossroad between three continents and as a stepping-stone outside Africa has evoked anthropological and genetic interest in this region. Numerous studies have described the genetic landscape of the human population in North Africa employing paternal, maternal, and biparental molecular markers. However, information from these markers which have different inheritance patterns has been mostly assessed independently, resulting in an incomplete description of the region. In this study, we analyze uniparental and genome-wide markers examining similarities or contrasts in the results and consequently provide a comprehensive description of the evolutionary history of North Africa populations. Our results show that both males and females in North Africa underwent a similar admixture history with slight differences in the proportions of admixture components. Consequently, genome-wide diversity show similar patterns with admixture tests suggesting North Africans are a mixture of ancestral populations related to current Africans and Eurasians with more affinity towards the out-of-Africa populations than to sub-Saharan Africans. We estimate from the paternal lineages that most North Africans emerged ∼15,000 years ago during the last glacial warming and that population splits started after the desiccation of the Sahara. Although most North Africans share a common admixture history, the Tunisian Berbers show long periods of genetic isolation and appear to have diverged from surrounding populations without subsequent mixture. On the other hand, continuous gene flow from the Middle East made Egyptians genetically closer to Eurasians than to other North Africans. We show that genetic diversity of today's North Africans mostly captures patterns from migrations post Last Glacial Maximum and therefore may be insufficient to inform on the initial population of the region during the Middle Paleolithic period.
Gravel, Simon; Wang, Wei; Brisbin, Abra; Byrnes, Jake K.; Fadhlaoui-Zid, Karima; Zalloua, Pierre A.; Moreno-Estrada, Andres; Bertranpetit, Jaume; Bustamante, Carlos D.; Comas, David
North African populations are distinct from sub-Saharan Africans based on cultural, linguistic, and phenotypic attributes; however, the time and the extent of genetic divergence between populations north and south of the Sahara remain poorly understood. Here, we interrogate the multilayered history of North Africa by characterizing the effect of hypothesized migrations from the Near East, Europe, and sub-Saharan Africa on current genetic diversity. We present dense, genome-wide SNP genotyping array data (730,000 sites) from seven North African populations, spanning from Egypt to Morocco, and one Spanish population. We identify a gradient of likely autochthonous Maghrebi ancestry that increases from east to west across northern Africa; this ancestry is likely derived from “back-to-Africa” gene flow more than 12,000 years ago (ya), prior to the Holocene. The indigenous North African ancestry is more frequent in populations with historical Berber ethnicity. In most North African populations we also see substantial shared ancestry with the Near East, and to a lesser extent sub-Saharan Africa and Europe. To estimate the time of migration from sub-Saharan populations into North Africa, we implement a maximum likelihood dating method based on the distribution of migrant tracts. In order to first identify migrant tracts, we assign local ancestry to haplotypes using a novel, principal component-based analysis of three ancestral populations. We estimate that a migration of western African origin into Morocco began about 40 generations ago (approximately 1,200 ya); a migration of individuals with Nilotic ancestry into Egypt occurred about 25 generations ago (approximately 750 ya). Our genomic data reveal an extraordinarily complex history of migrations, involving at least five ancestral populations, into North Africa. PMID:22253600
Staunton, Ciara; Tindana, Paulina; Hendricks, Melany; Moodley, Keymanthri
Genomic biobanking research is undergoing exponential growth in Africa raising a host of legal, ethical and social issues. Given the scientific complexity associated with genomics, there is a growing recognition globally of the importance of science translation and community engagement (CE) for this type of research, as it creates the potential to build relationships, increase trust, improve consent processes and empower local communities. Despite this level of recognition, there is a lack of empirical evidence of the practise and processes for effective CE in genomic biobanking in Africa. To begin to address this vacuum, 17 in-depth face to face interviews were conducted with South African experts in genomic biobanking research and CE to provide insight into the process, benefits and challenges of CE in South Africa. Emerging themes were analysed using a contextualised thematic approach. Several themes emerged concerning the conduct of CE in genomic biobanking research in Africa. Although the literature tends to focus on the local community in CE, respondents in this study described three different layers of stakeholder engagement: community level, peer level and high level. Community level engagement includes potential participants, community advisory boards (CAB) and field workers; peer level engagement includes researchers, biobankers and scientists, while high level engagement includes government officials, funders and policy makers. Although education of each stakeholder layer is important, education of the community layer can be most challenging, due to the complexity of the research and educational levels of stakeholders in this layer. CE is time-consuming and often requires an interdisciplinary research team approach. However careful planning of the engagement strategy, including an understanding of the differing layers of stakeholder engagement, and the specific educational needs at each layer, can help in the development of a relationship based on trust
Horton, Katherine C; Jiang, Ju; Maina, Alice; Dueger, Erica; Zayed, Alia; Ahmed, Ammar Abdo; Pimentel, Guillermo; Richards, Allen L
Of 49 workers at a Djiboutian abattoir, eight (16%, 95% confidence interval [CI]: 9-29) were seropositive against spotted fever group rickettsiae (SFGR), two (4%, 95% CI: 1-14) against typhus group rickettsiae, and three (6%, 95% CI: 2-17) against orientiae. One worker (9%, 95% CI: 2-38) seroconverted against orientiae during the study period. This is the first evidence of orientiae exposure in the Horn of Africa. SFGR were also identified by polymerase chain reaction in 32 of 189 (11%, 95% CI: 8-15) tick pools from 26 of 72 (36%) cattle. Twenty-five (8%, 95% CI: 6-12) tick pools were positive for Rickettsia africae, the causative agent of African tick-bite fever. Health-care providers in Djibouti should be aware of the possibility of rickettsiae infections among patients, although further research is needed to determine the impact of these infections in the country. © The American Society of Tropical Medicine and Hygiene.
Murray, Gemma G. R.; Weinert, Lucy A.; Rhule, Emma L.; Welch, John J.
Rickettsia is a genus of intracellular bacteria whose hosts and transmission strategies are both impressively diverse, and this is reflected in a highly dynamic genome. Some previous studies have described the evolutionary history of Rickettsia as non-tree-like, due to incongruity between phylogenetic reconstructions using different portions of the genome. Here, we reconstruct the Rickettsia phylogeny using whole-genome data, including two new genomes from previously unsampled host groups. We find that a single topology, which is supported by multiple sources of phylogenetic signal, well describes the evolutionary history of the core genome. We do observe extensive incongruence between individual gene trees, but analyses of simulations over a single topology and interspersed partitions of sites show that this is more plausibly attributed to systematic error than to horizontal gene transfer. Some conflicting placements also result from phylogenetic analyses of accessory genome content (i.e., gene presence/absence), but we argue that these are also due to systematic error, stemming from convergent genome reduction, which cannot be accommodated by existing phylogenetic methods. Our results show that, even within a single genus, tests for gene exchange based on phylogenetic incongruence may be susceptible to false positives. PMID:26559010
Full Text Available As genomic medicine gains clinical applicability across a spectrum of diseases, insufficient application in low-income settings stands to increase health disparity. Breast cancer screening, diagnosis, and treatment have benefited greatly from genomic medicine in high-income settings. As breast cancer is a leading cause of both cancer incidence and mortality in Africa, attention and resources must be applied to research and clinical initiatives to integrate genomic medicine into breast cancer care. In terms of research, there is a paucity of investigations into genetic determinants of breast cancer specific to African populations, despite consensus in the literature that predisposition and susceptibility genes vary between populations. Therefore, we need targeted strengthening of existing research efforts and support of new initiatives. Results will improve clinical care through screening and diagnosis with genetic testing specific to breast cancer in African populations. Clinically, genomic medicine can provide information capable of improving resource allocation to the population which most stands to benefit from increased screening or tailored treatment modalities. In situations where mammography or chemotherapy options are limited, this information will allow for the greatest impact. Implementation of genomic medicine will face numerous systemic barriers but is essential to improve breast cancer outcomes and survival.
Thomas K. Karikari
Full Text Available Modern genomic approaches have made enormous contributions to improving our understanding of the function, development and evolution of the nervous system, and the diversity within and between species. However, most of these research advances have been recorded in countries with advanced scientific resources and funding support systems. On the contrary, little is known about, for example, the possible interplay between different genes, non-coding elements and environmental factors in modulating neurological diseases among populations in low-income countries, including many African countries. The unique ancestry of African populations suggests that improved inclusion of these populations in neuroscience-related genomic studies would significantly help to identify novel factors that might shape the future of neuroscience research and neurological healthcare. This perspective is strongly supported by the recent identification that diseased individuals and their kindred from specific sub-Saharan African populations lack common neurological disease-associated genetic mutations. This indicates that there may be population-specific causes of neurological diseases, necessitating further investigations into the contribution of additional, presently-unknown genomic factors. Here, we discuss how the development of neurogenomics research in Africa would help to elucidate disease-related genomic variants, and also provide a good basis to develop more effective therapies. Furthermore, neurogenomics would harness African scientists' expertise in neuroscience, genomics and bioinformatics to extend our understanding of the neural basis of behaviour, development and evolution.
Adedokun, Babatunde O; Olopade, Christopher O; Olopade, Olufunmilayo I
The poor genomics research capacity of Sub-Saharan Africa (SSA) could prevent maximal benefits from the applications of genomics in the practice of medicine and research. The objective of this study is to examine the author affiliations of genomic epidemiology publications in order to make recommendations for building local genomics research capacity in SSA. SSA genomic epidemiology articles published between 2004 and 2013 were extracted from the Human Genome Epidemiology (HuGE) database. Data on authorship details, country of population studied, and phenotype or disease were extracted. Factors associated with the first author, who has an SSA institution affiliation (AIAFA), were determined using a Chi-square test and multiple logistic regression analysis. The most commonly studied population was South Africa, accounting for 31.1%, followed by Ghana (10.6%) and Kenya (7.5%). About one-tenth of the papers were related to non-communicable diseases (NCDs) such as cancer (6.1%) and cardiovascular diseases (CVDs) (4.3%). Fewer than half of the first authors (46.9%) were affiliated with an African institution. Among the 238 articles with an African first author, over three-quarters (79.8%) belonged to a university or medical school, 16.8% were affiliated with a research institute, and 3.4% had affiliations with other institutions. Significant disparities currently exist among SSA countries in genomics research capacity. South Africa has the highest genomics research output, which is reflected in the investments made in its genomics and biotechnology sector. These findings underscore the need to focus on developing local capacity, especially among those affiliated with SSA universities where there are more opportunities for teaching and research.
Azagi, Tal; Klement, Eyal; Perlman, Gidon; Lustig, Yaniv; Mumcuoglu, Kosta Y; Apanaskevich, Dmitry A; Gottlieb, Yuval
Hyalomma ticks (Acari: Ixodidae) are hosts for Francisella -like endosymbionts (FLE) and may serve as vectors of zoonotic disease agents. This study aimed to provide an initial characterization of the interaction between Hyalomma and FLE and to determine the prevalence of pathogenic Rickettsia in these ticks. Hyalomma marginatum , Hyalomma rufipes , Hyalomma dromedarii , Hyalomma aegyptium , and Hyalomma excavatum ticks, identified morphologically and molecularly, were collected from different hosts and locations representing the distribution of the genus Hyalomma in Israel, as well as from migratory birds. A high prevalence of FLE was found in all Hyalomma species (90.6%), as well as efficient maternal transmission of FLE (91.8%), and the localization of FLE in Malpighian tubules, ovaries, and salivary glands in H. marginatum Furthermore, we demonstrated strong cophylogeny between FLE and their host species. Contrary to FLE, the prevalence of Rickettsia ranged from 2.4% to 81.3% and was significantly different between Hyalomma species, with a higher prevalence in ticks collected from migratory birds. Using ompA gene sequences, most of the Rickettsia spp. were similar to Rickettsia aeschlimannii , while a few were similar to Rickettsia africae of the spotted fever group (SFG). Given their zoonotic importance, 249 ticks were tested for Crimean Congo hemorrhagic fever virus infection, and all were negative. The results imply that Hyalomma and FLE have obligatory symbiotic interactions, indicating a potential SFG Rickettsia zoonosis risk. A further understanding of the possible influence of FLE on Hyalomma development, as well as on its infection with Rickettsia pathogens, may lead to novel ways to control tick-borne zoonoses. IMPORTANCE This study shows that Francisella -like endosymbionts were ubiquitous in Hyalomma , were maternally transmitted, and cospeciated with their hosts. These findings imply that the interaction between FLE and Hyalomma is of an obligatory
Liu, Dan; Wang, Yuan-Zhi; Zhang, Huan; Liu, Zhi-Qiang; Wureli, Ha-zi; Wang, Shi-Wei; Tu, Chang-Chun; Chen, Chuang-Fu
Background Melophagus ovinus (Diptera: Hippoboscidae), a hematophagous ectoparasite, is mainly found in Europe, Northwestern Africa, and Asia. This wingless fly infests sheep, rabbits, and red foxes, and causes inflammation, wool loss and skin damage. Furthermore, this parasite has been shown to transmit diseases, and plays a role as a vector. Herein, we investigated the presence of various Rickettsia species in M. ovinus. Methods In this study, a total of 95 sheep keds were collected in Kuqa...
Herrick, Kristen L; Pena, Sandra A; Yaglom, Hayley D; Layton, Brent J; Moors, Amanda; Loftis, Amanda D; Condit, Marah E; Singleton, Joseph; Kato, Cecilia Y; Denison, Amy M; Ng, Dianna; Mertins, James W; Paddock, Christopher D
In the United States, all previously reported cases of Rickettsia parkeri rickettsiosis have been linked to transmission by the Gulf Coast tick (Amblyomma maculatum). Here we describe 1 confirmed and 1 probable case of R. parkeri rickettsiosis acquired in a mountainous region of southern Arizona, well beyond the recognized geographic range of A. maculatum ticks. The likely vector for these 2 infections was identified as the Amblyomma triste tick, a Neotropical species only recently recognized in the United States. Identification of R. parkeri rickettsiosis in southern Arizona demonstrates a need for local ecologic and epidemiologic assessments to better understand geographic distribution and define public health risk. Education and outreach aimed at persons recreating or working in this region of southern Arizona would improve awareness and promote prevention of tickborne rickettsioses.
El Karkouri, Khalid; Kowalczewska, Malgorzata; Armstrong, Nicholas; Azza, Said; Fournier, Pierre-Edouard; Raoult, Didier
Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG) rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT) and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF) and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s), compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., omp A/B and rick A) known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in these
Development and Validation of an Improved PCR Method Using the 23S-5S Intergenic Spacer for Detection of Rickettsiae in Dermacentor variabilis Ticks and Tissue Samples from Humans and Laboratory Animals
Kakumanu, Madhavi L.; Ponnusamy, Loganathan; Sutton, Haley T.; Meshnick, Steven R.; Nicholson, William L.
A novel nested PCR assay was developed to detect Rickettsia spp. in ticks and tissue samples from humans and laboratory animals. Primers were designed for the nested run to amplify a variable region of the 23S-5S intergenic spacer (IGS) of Rickettsia spp. The newly designed primers were evaluated using genomic DNA from 11 Rickettsia species belonging to the spotted fever, typhus, and ancestral groups and, in parallel, compared to other Rickettsia-specific PCR targets (ompA, gltA, and the 17-kDa protein gene). The new 23S-5S IGS nested PCR assay amplified all 11 Rickettsia spp., but the assays employing other PCR targets did not. The novel nested assay was sensitive enough to detect one copy of a cloned 23S-5S IGS fragment from “Candidatus Rickettsia amblyommii.” Subsequently, the detection efficiency of the 23S-5S IGS nested assay was compared to those of the other three assays using genomic DNA extracted from 40 adult Dermacentor variabilis ticks. The nested 23S-5S IGS assay detected Rickettsia DNA in 45% of the ticks, while the amplification rates of the other three assays ranged between 5 and 20%. The novel PCR assay was validated using clinical samples from humans and laboratory animals that were known to be infected with pathogenic species of Rickettsia. The nested 23S-5S IGS PCR assay was coupled with reverse line blot hybridization with species-specific probes for high-throughput detection and simultaneous identification of the species of Rickettsia in the ticks. “Candidatus Rickettsia amblyommii,” R. montanensis, R. felis, and R. bellii were frequently identified species, along with some potentially novel Rickettsia strains that were closely related to R. bellii and R. conorii. PMID:26818674
Pheiffer, Carmen; Humphries, Stephen E.; Gamieldien, Junaid; Erasmus, Rajiv T.
Aims. To conduct a genome-wide DNA methylation in individuals with type 2 diabetes, individuals with prediabetes, and control mixed ancestry individuals from South Africa. Methods. We used peripheral blood to perform genome-wide DNA methylation analysis in 3 individuals with screen detected diabetes, 3 individuals with prediabetes, and 3 individuals with normoglycaemia from the Bellville South Community, Cape Town, South Africa, who were age-, gender-, body mass index-, and duration of residency-matched. Methylated DNA immunoprecipitation (MeDIP) was performed by Arraystar Inc. (Rockville, MD, USA). Results. Hypermethylated DMRs were 1160 (81.97%) and 124 (43.20%), respectively, in individuals with diabetes and prediabetes when both were compared to subjects with normoglycaemia. Our data shows that genes related to the immune system, signal transduction, glucose transport, and pancreas development have altered DNA methylation in subjects with prediabetes and diabetes. Pathway analysis based on the functional analysis mapping of genes to KEGG pathways suggested that the linoleic acid metabolism and arachidonic acid metabolism pathways are hypomethylated in prediabetes and diabetes. Conclusions. Our study suggests that epigenetic changes are likely to be an early process that occurs before the onset of overt diabetes. Detailed analysis of DMRs that shows gradual methylation differences from control versus prediabetes to prediabetes versus diabetes in a larger sample size is required to confirm these findings. PMID:27555869
Venclíková, Kristýna; Rudolf, Ivo; Mendel, Jan; Betášová, Lenka; Hubálek, Zdeněk
Roč. 5, č. 2 (2014), s. 135-138 ISSN 1877-959X Institutional support: RVO:68081766 Keywords : Ixodes ricinus * Anaplasma phagocytophilum * Rickettsia spp. * Rickettsia helvetica * Rickettsia monacensis * Candidatus Neoehrlichia mikurensis Subject RIV: EE - Microbiology, Virology Impact factor: 2.718, year: 2014
... 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 antigens...
Tijsse-Klasen, E.; Fonville, M.; Overbeek, van L.S.; Reimerink, J.H.J.; Sprong, H.
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
Hajdušková, Eva; Literák, I.; Papoušek, I.; Costa, F.B.; Nováková, M.; Labruna, M. B.; Zdražilová-Dubská, L.
Roč. 7, č. 3 (2016), s. 482-486 ISSN 1877-959X Institutional support: RVO:60077344 Keywords : Rickettsiae * Candidatus Rickettsia mendelii * Ixodes ricinus * basal group rickettsiae * ticks * Czech Republic Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.230, year: 2016
Ionita, Mariana; Silaghi, Cornelia; Mitrea, Ioan Liviu; Edouard, Sophie; Parola, Philippe; Pfister, Kurt
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. Copyright © 2015 Elsevier GmbH. All rights reserved.
Masiye, Francis; Mayosi, Bongani; de Vries, Jantina
Advances in genetic and genomic research have introduced challenges in obtaining informed consent for research in low and middle-income settings. However, there are only few studies that have explored challenges in obtaining informed consent in genetic and genomic research in Africa and none in South Africa. To start filling this gap, we conducted an empirical study to investigate the efficacy of informed consent procedures for an H3Africa genomic study on Rheumatic Heart Disease (RHDGen) at the University of Cape Town in South Africa. The main aim of the study was to understand ethical challenges in obtaining informed consent in the RHDGen study. We used a qualitative study methodology involving in-depth interviews and participant observations. Our study participants were RHDGen cases (patients), healthy controls and research staff involved in the recruitment of RHDGen cases and controls. In total, we conducted 32 in-depth interviews with RHDGen cases and controls, 2 in-depth interviews with research staff and 57 direct observations of the consent procedures of RHDGen cases and controls. The interviews were conducted in English, audio-recorded and transcribed verbatim. Data were analyzed using thematic content analysis. The study was conducted in 3 sites within Cape Town, South Africa. Most healthy controls joined the RHDGen study in order to be screened for rheumatic heart disease (diagnostic misconception). A majority of RHDGen cases decided to join the RHDGen study because of therapeutic misconception. The ethical challenges that impacted on obtaining informed consent in the RHDGen study were complex. In this study, the main challenges were diagnostic misconception among RHDGen controls and therapeutic misconception among RHDGen cases.
do Amaral, Renan Bressianini; Lourenço, Elizabete Captivo; Famadas, Kátia Maria; Garcia, Amanda Barbosa; Machado, Rosangela Zacarias; André, Marcos Rogério
The family Streblidae comprises a monophyletic group of Hippoboscoidea, hematophagous dipterans that parasitize bats. Bartonella spp. and Rickettsia spp. have been reported in bats sampled in Europe, Africa, Asia, North, Central and South America. However, there are few reports on the Bartonella and Rickettsia bacteria infecting Hippoboscoidea flies and mites. While Spinturnicidae mites are ectoparasites found only in bats, those belonging to the family Macronyssidae comprise mites that also parasitize other mammal species. This study investigates the occurrence and assesses the phylogenetic positioning of Bartonella spp. and Rickettsia spp. found in Streblidae flies and Spinturnicidae and Macronyssidae mites collected from bats captured in Brazil. From May 2011 to April 2012 and September 2013 to December 2014, 400 Streblidae flies, 100 Macronyssidaes, and 100 Spinturnicidae mites were collected from bats captured in two sites in northeastern Nova Iguaçu, Rio de Janeiro, southeastern Brazil. Forty (19.8%) out of 202 Streblidae flies were positive for Bartonella spp. in qPCR assays based on the nuoG gene. Among the flies positive for the bacterium, six (18%) were Paratrichobius longicrus, seven (29%) Strebla guajiro, two (40%) Aspidoptera phyllostomatis, five (11%) Aspidoptera falcata, one (10%) Trichobius anducei, one (25%) Megistopoda aranea, and 18 (32%) Trichobius joblingi, and collected from bats of the following species: Artibeus lituratus, Carollia perspicillata, Artibeus planirostris, Sturnira lilium, and Artibeus obscurus. Six sequences were obtained for Bartonella (nuoG [n = 2], gltA [n = 2], rpoB [n = 1], ribC = 1]). The phylogenetic analysis based on gltA (750pb) gene showed that the Bartonella sequences clustered with Bartonella genotypes detected in bats and ectoparasites previously sampled in Latin America, including Brazil. Only one sample (0.49%) of the species Trichobius joblingi collected from a specimen of Carollia perspicillata was positive
Portillo, Aránzazu; de Sousa, Rita; Santibáñez, Sonia; Duarte, Ana; Edouard, Sophie; Fonseca, Isabel P; Marques, Cátia; Novakova, Marketa; Palomar, Ana M; Santos, Marcos; Silaghi, Cornelia; Tomassone, Laura; Zúquete, Sara; Oteo, José A
The genus Rickettsia (Rickettsiales: Rickettsiaceae) includes Gram-negative, small, obligate intracellular, nonmotile, pleomorphic coccobacilli bacteria transmitted by arthropods. Some of them cause human and probably also animal disease (life threatening in some patients). In these guidelines, we give clinical practice advices (microscopy, serology, molecular tools, and culture) for the microbiological study of these microorganisms in clinical samples. Since in our environment rickettsioses are mainly transmitted by ticks, practical information for the identification of these arthropods and for the study of Rickettsia infections in ticks has also been added.
Rudolf, I.; Venclíková, Kristýna; Blažejová, H.; Betášová, L.; Mendel, J.; Hubálek, Z.; Parola, P.
Roč. 7, č. 6 (2016), s. 1222-1224 ISSN 1877-959X Institutional support: RVO:61389013 Keywords : Rickettsia spp. * Dermacentor spp. * DEBONEL Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.230, year: 2016
de Barros Lopes, Lívia; Guterres, Alexandro; Rozental, Tatiana; Carvalho de Oliveira, Renata; Mares-Guia, Maria Angélica; Fernandes, Jorlan; Figueredo, José Ferreira; Anschau, Inês; de Jesus, Sebastião; V Almeida, Ana Beatriz M; Cristina da Silva, Valéria; Gomes de Melo Via, Alba Valéria; Bonvicino, Cibele Rodrigues; D’Andrea, Paulo Sérgio; Barreira, Jairo Dias
Background The purpose of this study was to identify the presence of rickettsia and hantavirus in wild rodents and arthropods in response to an outbreak of acute unidentified febrile illness among Indians in the Halataikwa Indian Reserve, northwest of the Mato Grosso state, in the Brazilian Amazon. Where previously surveillance data showed serologic evidence of rickettsia and hantavirus human infection. Methods The arthropods were collected from the healthy Indian population and by flagging v...
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.
Kuscu, Ferit; Orkun, Omer; Ulu, Aslihan; Kurtaran, Behice; Komur, Suheyla; Inal, A Seza; Erdogan, Damla; Tasova, Yesim; Aksu, Hasan S Z
In 2016, Rickettsia sibirica mongolitimonae was diagnosed for a man in Turkey. He had been bitten by a Hyalomma marginatum tick, from which PCR detected rickettsial DNA. Sequence analysis of the DNA identified R. sibirica mongolitimonae. Immunofluorescence assay of patient serum indicated R. conorii, which cross-reacts. PCR is recommended for rickettsiosis diagnoses.
infected soldiers in the Viet Nam War. These rickettsiae have continued to attract research support. Although R. conorii has received far less...principally for reasons of location related to cosmetic concern or proximity to vital structures, e.g., carotid artery. Other patients had boutonneuse fever
Malaisri, Premnika; Hirunkanokpun, Supanee; Baimai, Visut; Trinachartvanit, Wachareeporn; Ahantarig, Arunee
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. © 2015 The Society for Vector Ecology.
Liu, Dan; Wang, Yuan-Zhi; Zhang, Huan; Liu, Zhi-Qiang; Wureli, Ha-Zi; Wang, Shi-Wei; Tu, Chang-Chun; Chen, Chuang-Fu
Melophagus ovinus (Diptera: Hippoboscidae), a hematophagous ectoparasite, is mainly found in Europe, Northwestern Africa, and Asia. This wingless fly infests sheep, rabbits, and red foxes, and causes inflammation, wool loss and skin damage. Furthermore, this parasite has been shown to transmit diseases, and plays a role as a vector. Herein, we investigated the presence of various Rickettsia species in M. ovinus. In this study, a total of 95 sheep keds were collected in Kuqa County and Alaer City southern region of Xinjiang Uygur Autonomous Region, northwestern China. First, collected sheep keds were identified on the species level using morphological keys and molecular methods based on a fragment of the 18S ribosomal DNA gene (18S rDNA). Thereafter, to assess the presence of rickettsial DNA in sheep keds, the DNA of individual samples was screened by PCR based on six Rickettsia-specific gene fragments originating from six genes: the 17-kilodalton antigen gene (17-kDa), 16S rRNA gene (rrs), surface cell antigen 4 gene (sca4), citrate synthase gene (gltA), and outer membrane protein A and B genes (ompA and ompB). The amplified products were confirmed by sequencing and BLAST analysis ( https://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=blastn&PAGE_TYPE=BlastSearch&LINK_LOC=blasthome ). According to its morphology and results of molecular analysis, the species was identified as Melophagus ovinus, with 100% identity to M. ovinus from St. Kilda, Australia (FN666411). DNA of Rickettsia spp. were found in 12 M. ovinus samples (12.63%, 12/95). Rickettsia raoultii and R. slovaca were confirmed based on phylogenetic analysis, although the genetic markers of these two rickettsial agents amplified in this study showed molecular diversity. This is the first report of R. raoultii and R. slovaca DNA in M. ovinus. Rickettsia slovaca was found for the first time around the Taklimakan Desert located in China. This finding extends the geographical range of spotted fever group
Full Text Available Abstract Background Melophagus ovinus (Diptera: Hippoboscidae, a hematophagous ectoparasite, is mainly found in Europe, Northwestern Africa, and Asia. This wingless fly infests sheep, rabbits, and red foxes, and causes inflammation, wool loss and skin damage. Furthermore, this parasite has been shown to transmit diseases, and plays a role as a vector. Herein, we investigated the presence of various Rickettsia species in M. ovinus. Methods In this study, a total of 95 sheep keds were collected in Kuqa County and Alaer City southern region of Xinjiang Uygur Autonomous Region, northwestern China. First, collected sheep keds were identified on the species level using morphological keys and molecular methods based on a fragment of the 18S ribosomal DNA gene (18S rDNA. Thereafter, to assess the presence of rickettsial DNA in sheep keds, the DNA of individual samples was screened by PCR based on six Rickettsia-specific gene fragments originating from six genes: the 17-kilodalton antigen gene (17-kDa, 16S rRNA gene (rrs, surface cell antigen 4 gene (sca4, citrate synthase gene (gltA, and outer membrane protein A and B genes (ompA and ompB. The amplified products were confirmed by sequencing and BLAST analysis ( https://blast.ncbi.nlm.nih.gov/Blast.cgi?PROGRAM=blastn&PAGE_TYPE=BlastSearch&LINK_LOC=blasthome . Results According to its morphology and results of molecular analysis, the species was identified as Melophagus ovinus, with 100% identity to M. ovinus from St. Kilda, Australia (FN666411. DNA of Rickettsia spp. were found in 12 M. ovinus samples (12.63%, 12/95. Rickettsia raoultii and R. slovaca were confirmed based on phylogenetic analysis, although the genetic markers of these two rickettsial agents amplified in this study showed molecular diversity. Conclusions This is the first report of R. raoultii and R. slovaca DNA in M. ovinus. Rickettsia slovaca was found for the first time around the Taklimakan Desert located in China. This finding
Chochlakis, Dimosthenis; Bongiorni, Christine; Partalis, Nikolaos; Tselentis, Yannis; Psaroulaki, Anna
Tick-borne rickettsioses are endemic in Greece; however, until recently, only Rickettsia typhi and R. conorii were tested routinely in human samples arriving at the National Reference Center. During the last few years, the identification of different rickettsia species in ticks led to the introduction of other spotted fever group rickettsiae in routine analysis. Under the new scheme, R. massiliae is now tested routinely in human samples; herein, we describe a human case of this infection.
Rickettsia parkeri in Gulf Coast Ticks, Southeastern Virginia, USA Chelsea L. Wright, Robyn M. Nadolny, Ju Jiang, Allen L. Richards, Daniel E...Virginia. We found that 43.1% of the adult Gulf Coast ticks collected in the summer of 2010 carried Rickettsia parkeri, suggesting that persons living in...or visiting southeastern Virginia are at risk for infection with this pathogen. Rickettsia parkeri is an obligate intracellular bacterium belonging
Detecting Rickettsia parkeri Infection from Eschar Swab Specimens Todd Myers, Tahaniyat Lalani, Mike Dent, Ju Jiang, Patrick L. Daly, Jason D...Maguire, and Allen L. Richards The typical clinical presentation of several spotted fever group Rickettsia infections includes eschars. Clinical...diagnosis by using an eschar swab specimen from patients infected with Rickettsia parkeri. Until 2004, all confirmed cases of tick-borne spotted
Detection of Rickettsia amblyommii in Amblyomma americanum Parasitizing Humans Ju Jiang~ Tamasin Yarina~ Melissa K. Miller,2 Ellen Y. Stromdahl? and...protein B gene (ompB) of Rickettsia amblyommii was employed to assess the threat of R. amblyommii exposure to humans parasitized by Amblyomma americanum...infection of and possibly disease in humans. Key Words: Amblyomma americanum-Lone star ticks-Real-time PCR- Rickettsia amblyommii. Introduction R
Moreira-Soto, Rolando D; Moreira-Soto, Andrés; Corrales-Aguilar, Eugenia; Calderón-Arguedas, Ólger; Troyo, Adriana
Rickettsiae are intracellular bacteria commonly associated with hematophagous arthropods. Most of them have been described in hard ticks, but some have been found in soft ticks. Here we report the detection and isolation of a new Rickettsia from Ornithodoros knoxjonesi larvae collected from Balantiopteryx plicata (Emballonuridae) in Nicoya, Costa Rica. Two ticks were processed to detect Rickettsia spp. genes gltA, ompA, ompB, and htrA by PCR. Part of the macerate was also inoculated into Vero E6 and C6/36 cell lines, and cells were evaluated by Giménez stain, indirect immunofluorescence assay (IFA), and PCR. Both ticks were positive by PCR and rickettsial growth was successful in Vero E6 cells. Amplification and sequencing of near full length rrs, gltA, sca4 genes, and fragments of ompA and ompB showed that the Rickettsia sp. was different from described species. The highest homologies were with 'Candidatus Rickettsia wissemanii' and Rickettsia peacockii: 99.70% (1321/1325) with both sequences for rrs, 99.58% (1172/1177) and 99.76% (1246/1249) for gltA, 99.26% with both sequences (2948/2970 and 2957/2979) for sca4, 98.78% (485/491) and 98.39% (2069/2115) for ompA, and 98.58 (1453/1474) and 98.92% (1459/1475) for ompB; respectively. Bat blood, spleen, liver, and lung samples analyzed for Rickettsia detection were negative. Results demonstrate that the Rickettsia isolated from O. knoxjonesi is probably an undescribed species that belongs to the spotted fever group, for which 'Candidatus Rickettsia nicoyana' is proposed. Considering that B. plicata inhabits areas where contact with humans may occur and that human parasitism by Ornithodoros has been reported in the country, it will be important to continue with the characterization of this species and its pathogenic potential. Copyright © 2017 Elsevier GmbH. All rights reserved.
Cotterill, Fenton P. D.
Press). Equally, Africa's freshwater fish fauna stands apart in its high endemism, preponderance of highly specialized species flocks, and ancient lineages that have seeded recent radiations (Otero O 2010. Cybium 2010, 34(1): 93-113). Nevertheless, Africa's fossil record - botanical and zoological - is too patchy and incomplete to build palaeoenvironmental narratives with the precision needed to resolve details of mesoscale events in landscape dynamics (especially at timescales >10 000 yr). Ideally, the biological evidence we seek to resolve a high fidelity narrative of landscape dynamics must extend back into the Cenozoic, and quantify turnovers of individual species on respective landforms. Births, deaths and tenures of species are its core currencies. The genomic record holds this evidence in its evolutionary archives, and we can read these signatures in the DNA of living organisms. This interdisciplinary approach exploits patterns of DNA variation in living organisms to reconstruct evolutionary events in landscape history at the mesoscale. Coupling the technological advances in 21st century molecular biology (especially genomics) with key tenets of ecological theory, we can exploit the remarkable variety of evolutionary signals preserved in the extant biodiversity of a landscape. Deciphering the genomic record, Geoecodynamics exploits the fidelity of individual species to their respective habitats; where the biota has persisted within/on encompassing landforms. This spatial resolution is determined principally by the degree of niche conservatism that has acted to lock the species into finite ecophysiological boundaries in the landscape. These ecophysiological envelopes of species can be mapped and modelled in a GIS framework, using variables familiar to geomorphologists: including altitude, surface roughness, lithology, and especially drainage attributes (stream topology and limnological variables). Geoecodynamics studies terrestrial and aquatic species as
Lee, J K; Moraru, G M; Stokes, J V; Wills, R W; Mitchell, E; Unz, E; Moore-Henderson, B; Harper, A B; Varela-Stokes, A S
Amblyomma maculatum Koch (Acari: Ixodidae), the primary vector for Rickettsia parkeri, may also be infected with a rickettsia of unknown pathogenicity, "Candidatus Rickettsia andeanae." Infection rates with these rickettsiae vary geographically, and coinfected ticks have been reported. In this study, infection rates of R. parkeri and "Ca. R. andeanae" were evaluated, and rickettsial DNA levels quantified, in 335 questing adult A. maculatum collected in 2013 (n = 95), 2014 (n = 139), and 2015 (n = 101) from Oktibbeha County, MS. Overall infection rates of R. parkeri and "Ca. R. andeanae" were 28.7% and 9.3%, respectively, with three additional A. maculatum (0.9%) coinfected. While R. parkeri-infected ticks were detected all three years (34.7% in 2013; 13.7% in 2014; 43.6% in 2015), "Ca. R. andeanae" was not detected in 2013, and was detected at rates of 10.8% in 2014, and 15.8% in 2015. Interestingly, rickettsial DNA levels in singly-infected ticks were significantly lower in "Ca. R. andeanae"-infected ticks compared to R. parkeri-infected ticks (P Rickettsia species in A. maculatum at the population level. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Mol, Michael J.; Stadler, Christian; Ariño, Africa
Context matters in the global strategy literature. We discuss how Africa, as a setting that received limited attention in the past, offers opportunity to challenge existing theory and develop new insights. The overall goal is to ask: What will the field of global strategic management look like once...
Márquez, F J; Rojas, A; Ibarra, V; Cantero, A; Rojas, J; Oteo, J A; Muniain, M A
In southern Spain, Dermacentor marginatus ticks can be infected with several genospecies of spotted fever Group (SFG) Rickettsia. We developed a nested polymerase chain reaction assay by using a species-specific probe targeting the ompA gene to detect and differentiate between the two groups of rickettsiae previously described in D. marginatus. SFG rickettsia has been detected in 85.15% of ticks studied (26.7% of positives have been to R. slovaca, the causative agent of TIBOLA-DEBONEL, and 73.3% to SFG rickettsia closely related to strains RpA4-JL-02-DnS14-DnS28).
Loots, Angelika K; Du Plessis, Morné; Dalton, Desiré Lee; Mitchell, Emily; Venter, Estelle H
Canine distemper virus causes global multihost infectious disease. This report details complete genome sequences of three vaccine and two new wild-type strains. The wild-type strains belong to the South African lineage, and all three vaccine strains to the America 1 lineage. This constitutes the first genomic sequences of this virus from South Africa. Copyright © 2017 Loots et al.
Atkinson, W.H.; Winkler, H.H.
Rickettsia prowazekii accumulated radioactivity from [adenine-2,8-3H]NAD but not from [nicotinamide-4-3H]NAD, which demonstrated that NAD was not taken up intact. Extracellular NAD was hydrolyzed by rickettsiae with the products of hydrolysis, nicotinamide mononucleotide and AMP, appearing in the incubation medium in a time- and temperature-dependent manner. The particulate (membrane) fraction contained 90% of this NAD pyrophosphatase activity. Rickettsiae which had accumulated radiolabel after incubation with [adenine-2,8-3H]NAD were extracted, and the intracellular composition was analyzed by chromatography. The cells contained labeled AMP, ADP, ATP, and NAD. The NAD-derived intracellular AMP was transported via a pathway distinct from and in addition to the previously described AMP translocase. Exogenous AMP (1 mM) inhibited uptake of radioactivity from [adenine-2,8-3H]NAD and hydrolysis of extracellular NAD. AMP increased the percentage of intracellular radiolabel present as NAD. Nicotinamide mononucleotide was not taken up by the rickettsiae, did not inhibit hydrolysis of extracellular NAD, and was not a good inhibitor of the uptake of radiolabel from [adenine-2,8-3H]NAD. Neither AMP nor ATP (both of which are transported) could support the synthesis of intracellular NAD. The presence of intracellular [adenine-2,8-3H]NAD within an organism in which intact NAD could not be transported suggested the resynthesis from AMP of [adenine-2,8-3H]NAD at the locus of NAD hydrolysis and translocation
Khalid El Karkouri
Full Text Available Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s, compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., ompA/B and rickA known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in
El Karkouri, Khalid; Kowalczewska, Malgorzata; Armstrong, Nicholas; Azza, Said; Fournier, Pierre-Edouard; Raoult, Didier
Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG) rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT) and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF) and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s), compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., ompA/B and rickA) known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in these rickettsiae
Fadhlaoui-Zid, Karima; Haber, Marc, 1980-; Martínez Cruz, Begoña; Zalloua, Pierre A; Elgaaied, Amel Benammar; Comas, David, 1969-
The geostrategic location of North Africa as a crossroad between three continents and as a stepping-stone outside Africa has evoked anthropological and genetic interest in this region. Numerous studies have described the genetic landscape of the human population in North Africa employing paternal, maternal, and biparental molecular markers. However, information from these markers which have different inheritance patterns has been mostly assessed independently, resulting in an incomplete descr...
Zaharia, Mihaela; Popescu, Corneliu Petru; Florescu, Simin Aysel; Ceausu, Emanoil; Raoult, Didier; Parola, Philippe; Socolovschi, Cristina
The purpose of this prospective study is to describe the clinical and epidemiological characteristics of rickettsioses in Romania, where only Rickettsia conorii is known by clinicians but new Rickettsia species have been identified recently in ticks. A total of eight patients, including a nine-year-old child, were included between June 2011 and June 2012, in the Hospital for Infectious and Tropical Diseases, Bucharest, Romania. Seven cases presented during summer months and one in spring. Six patients presented a generalized rash with fever, myalgia and skin eschar. The last two patients presented a typical SENLAT syndrome, characterized by scalp eschar and neck lymphadenopathy. Using serological tools, we confirmed for the first time two cases of Rickettsia massiliae, the agent of spotted fever disease, and one case of Rickettsia slovaca, and one case of R. slovacaRickettsia raoultii the agents of SENLAT syndrome. Copyright © 2016 Elsevier GmbH. All rights reserved.
Brown, A; Ojango, J; Gibson, J; Coffey, M; Okeyo, M; Mrode, R
Due to the absence of accurate pedigree information, it has not been possible to implement genetic evaluations for crossbred cattle in African small-holder systems. Genomic selection techniques that do not rely on pedigree information could, therefore, be a useful alternative. The objective of this study was to examine the feasibility of using genomic selection techniques in a crossbred cattle population using data from Kenya provided by the Dairy Genetics East Africa Project. Genomic estimated breeding values for milk yield were estimated using 2 prediction methods, GBLUP and BayesC, and accuracies were calculated as the correlation between yield deviations and genomic breeding values included in the estimation process, mimicking the situation for young bulls. The accuracy of evaluation ranged from 0.28 to 0.41, depending on the validation population and prediction method used. No significant differences were found in accuracy between the 2 prediction methods. The results suggest that there is potential for implementing genomic selection for young bulls in crossbred small-holder cattle populations, and targeted genotyping and phenotyping should be pursued to facilitate this. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Rudolf, Ivo; Venclíková, Kristýna; Blažejová, Hana; Betášová, Lenka; Mendel, Jan; Hubálek, Zdeněk; Parola, P.
Roč. 7, č. 6 (2016), s. 1222-1224 ISSN 1877-959X Institutional support: RVO:68081766 Keywords : Rickettsia spp. * Dermacentor spp. * DEBONEL * SENLAT Subject RIV: GJ - Animal Vermins ; Diseases , Veterinary Medicine Impact factor: 3.230, year: 2016
Sprong, H.; Wielinga, P.R.; Fonville, M.; Reusken, C.; Brandenburg, A.H.; Borgsteede, F.H.M.
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.
Pagani, Luca; Schiffels, Stephan; Gurdasani, Deepti; Danecek, Petr; Scally, Aylwyn; Chen, Yuan; Xue, Yali; Haber, Marc; Ekong, Rosemary; Oljira, Tamiru; Mekonnen, Ephrem; Luiselli, Donata; Bradman, Neil; Bekele, Endashaw; Zalloua, Pierre; Durbin, Richard; Kivisild, Toomas; Tyler-Smith, Chris
The predominantly African origin of all modern human populations is well established, but the route taken out of Africa is still unclear. Two alternative routes, via Egypt and Sinai or across the Bab el Mandeb strait into Arabia, have traditionally been proposed as feasible gateways in light of geographic, paleoclimatic, archaeological, and genetic evidence. Distinguishing among these alternatives has been difficult. We generated 225 whole-genome sequences (225 at 8× depth, of which 8 were increased to 30×; Illumina HiSeq 2000) from six modern Northeast African populations (100 Egyptians and five Ethiopian populations each represented by 25 individuals). West Eurasian components were masked out, and the remaining African haplotypes were compared with a panel of sub-Saharan African and non-African genomes. We showed that masked Northeast African haplotypes overall were more similar to non-African haplotypes and more frequently present outside Africa than were any sets of haplotypes derived from a West African population. Furthermore, the masked Egyptian haplotypes showed these properties more markedly than the masked Ethiopian haplotypes, pointing to Egypt as the more likely gateway in the exodus to the rest of the world. Using five Ethiopian and three Egyptian high-coverage masked genomes and the multiple sequentially Markovian coalescent (MSMC) approach, we estimated the genetic split times of Egyptians and Ethiopians from non-African populations at 55,000 and 65,000 years ago, respectively, whereas that of West Africans was estimated to be 75,000 years ago. Both the haplotype and MSMC analyses thus suggest a predominant northern route out of Africa via Egypt. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
Allen, Julie M.; Koga, Ryuichi; Fukatsu, Takema; Sweet, Andrew D.; Johnson, Kevin P.; Reed, David L.
ABSTRACT Roughly 10% to 15% of insect species host heritable symbiotic bacteria known as endosymbionts. The lice parasitizing mammals rely on endosymbionts to provide essential vitamins absent in their blood meals. Here, we describe two bacterial associates from a louse, Proechinophthirus fluctus, which is an obligate ectoparasite of a marine mammal. One of these is a heritable endosymbiont that is not closely related to endosymbionts of other mammalian lice. Rather, it is more closely related to endosymbionts of the genus Sodalis associated with spittlebugs and feather-chewing bird lice. Localization and vertical transmission of this endosymbiont are also more similar to those of bird lice than to those of other mammalian lice. The endosymbiont genome appears to be degrading in symbiosis; however, it is considerably larger than the genomes of other mammalian louse endosymbionts. These patterns suggest the possibility that this Sodalis endosymbiont might be recently acquired, replacing a now-extinct, ancient endosymbiont. From the same lice, we also identified an abundant bacterium belonging to the genus Rickettsia that is closely related to Rickettsia ricketsii, a human pathogen vectored by ticks. No obvious masses of the Rickettsia bacterium were observed in louse tissues, nor did we find any evidence of vertical transmission, so the nature of its association remains unclear. IMPORTANCE Many insects are host to heritable symbiotic bacteria. These heritable bacteria have been identified from numerous species of parasitic lice. It appears that novel symbioses have formed between lice and bacteria many times, with new bacterial symbionts potentially replacing existing ones. However, little was known about the symbionts of lice parasitizing marine mammals. Here, we identified a heritable bacterial symbiont in lice parasitizing northern fur seals. This bacterial symbiont appears to have been recently acquired by the lice. The findings reported here provide insights
Full Text Available Treponema pallidum subsp. pertenue (TPE is the causative agent of yaws, a multi-stage disease, endemic in tropical regions of Africa, Asia, Oceania, and South America. To date, four TPE strains have been completely sequenced including three TPE strains of human origin (Samoa D, CDC-2, and Gauthier and one TPE strain (Fribourg-Blanc isolated from a baboon. All TPE strains are highly similar to T. pallidum subsp. pallidum (TPA strains. The mutation rate in syphilis and related treponemes has not been experimentally determined yet.Complete genomes of two TPE strains, CDC 2575 and Ghana-051, that infected patients in Ghana and were isolated in 1980 and 1988, respectively, were sequenced and analyzed. Both strains had identical consensus genome nucleotide sequences raising the question whether TPE CDC 2575 and Ghana-051 represent two different strains. Several lines of evidence support the fact that both strains represent independent samples including regions showing intrastrain heterogeneity (13 and 5 intrastrain heterogeneous sites in TPE Ghana-051 and TPE CDC 2575, respectively. Four of these heterogeneous sites were found in both genomes but the frequency of alternative alleles differed. The identical consensus genome sequences were used to estimate the upper limit of the yaws treponeme evolution rate, which was 4.1 x 10-10 nucleotide changes per site per generation.The estimated upper limit for the mutation rate of TPE was slightly lower than the mutation rate of E. coli, which was determined during a long-term experiment. Given the known diversity between TPA and TPE genomes and the assumption that both TPA and TPE have a similar mutation rate, the most recent common ancestor of syphilis and yaws treponemes appears to be more than ten thousand years old and likely even older.
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
Khrouf, Fatma; Sellami, Hanene; Elleuch, Emna; Hattab, Zouhour; Ammari, Lamia; Khalfaoui, Moncef; Souissi, Jihed; Harrabi, Hejer; M'ghirbi, Youmna; Tiouiri, Hanene; Ben Jemaa, Mounir; Hammami, Adnene; Letaief, Amel; Bouattour, Ali; Znazen, Abir
Diagnosis of rickettsioses had largely benefited from the development of molecular techniques. Unfortunately, in Tunisia, despite the large number of rickettsial cases registered every year, the Rickettsia species remain unidentified. In this study, we aimed to detect the Rickettsia species in clinical samples using molecular tests. A study was established to analyze skin biopsies, cutaneous swabs, and cerebrospinal fluid samples taken from clinically suspected patients to have rickettsial infection. Two molecular techniques were used to detect Rickettsia DNA: quantitative real time PCR (qPCR) and reverse line blot test (RLB). An analysis of the RLB hybridization assay results revealed the presence of Rickettsia DNA in skin biopsies (40.6%) and swabs (46.7%). Rickettsia conorii was the most prevalent identified species among tested samples. Other species of interest include Rickettsia typhi and Rickettsia massiliae. Using qPCR positivity rates in skin biopsies was 63.7% against 80% in swabs. R. conorii was the most frequently detected species, followed by R. typhi. The agreement between the two techniques was 68.6% (kappa=0.33). Molecular tests, especially using specific probes qPCR, allow for a rapid, better and confident diagnosis in clinical practice. They improve the survey of Mediterranean spotted fever which is considered to be the most important rickettsial infection in humans in Tunisia. Copyright © 2016 Elsevier GmbH. All rights reserved.
Comas, Iñaki; Hailu, Elena; Kiros, Teklu; Bekele, Shiferaw; Mekonnen, Wondale; Gumi, Balako; Tschopp, Rea; Ameni, Gobena; Hewinson, R Glyn; Robertson, Brian D; Goig, Galo A; Stucki, David; Gagneux, Sebastien; Aseffa, Abraham; Young, Douglas; Berg, Stefan
Colonial medical reports claimed that tuberculosis (TB) was largely unknown in Africa prior to European contact, providing a "virgin soil" for spread of TB in highly susceptible populations previously unexposed to the disease [1, 2]. This is in direct contrast to recent phylogenetic models which support an African origin for TB [3-6]. To address this apparent contradiction, we performed a broad genomic sampling of Mycobacterium tuberculosis in Ethiopia. All members of the M. tuberculosis complex (MTBC) arose from clonal expansion of a single common ancestor  with a proposed origin in East Africa [3, 4, 8]. Consistent with this proposal, MTBC lineage 7 is almost exclusively found in that region [9-11]. Although a detailed medical history of Ethiopia supports the view that TB was rare until the 20(th) century , over the last century Ethiopia has become a high-burden TB country . Our results provide further support for an African origin for TB, with some genotypes already present on the continent well before European contact. Phylogenetic analyses reveal a pattern of serial introductions of multiple genotypes into Ethiopia in association with human migration and trade. In place of a "virgin soil" fostering the spread of TB in a previously naive population, we propose that increased TB mortality in Africa was driven by the introduction of European strains of M. tuberculosis alongside expansion of selected indigenous strains having biological characteristics that carry a fitness benefit in the urbanized settings of post-colonial Africa. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Lephoto, Tiisetso E; Featherston, Jonathan; Gray, Vincent M
Here, we report on the draft genome sequence of Serratia sp. strain TEL, associated with Oscheius sp. TEL-2014 (Nematoda: Rhabditidae, KM492926) isolated from a grassland in Suikerbosrand Nature Reserve near Johannesburg in South Africa. Serratia sp. strain TEL has a genome size of 5,000,541 bp with 4,647 genes and a G+C content of 59.1%. Copyright © 2015 Lephoto et al.
Lephoto, Tiisetso E.; Featherston, Jonathan; Gray, Vincent M.
Here, we report on the draft genome sequence of Serratia sp. strain TEL, associated with Oscheius sp. TEL-2014 (Nematoda: Rhabditidae, KM492926) isolated from a grassland in Suikerbosrand Nature Reserve near Johannesburg in South Africa. Serratia sp. strain TEL has a genome size of 5,000,541 bp with 4,647 genes and a G+C content of 59.1%.
Khrouf, Fatma; M'Ghirbi, Youmna; Znazen, Abir; Ben Jemaa, Mounir; Hammami, Adnene
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. PMID:24226919
Lopes, Marcos G; May Junior, Joares; Foster, Rebecca J; Harmsen, Bart J; Sanchez, Emma; Martins, Thiago F; Quigley, Howard; Marcili, Arlei; Labruna, Marcelo B
The agents of spotted fevers in Latin America are Rickettsia rickettsii, R. parkeri, Rickettsia sp. strain Atlantic rainforest, and R. massiliae. In Continental Central America, R. rickettsii remains the only known pathogenic tick-borne rickettsia. In the present study, ticks were collected from wild mammals in natural areas of Belize. Besides providing new data of ticks from Belize, we investigated rickettsial infection in some of these ticks. Our results provide ticks harboring rickettsial agents for the first time in Central America. Between 2010 and 2015, wild mammals were lived-trapped in the tropical broadleaf moist forests of central and southern Belize. Ticks were collected from the animals and identified to species by morphological and molecular analysis (DNA sequence of the tick mitochondrial 16S RNA gene). Some of the ticks were tested for rickettsial infection by molecular methods (DNA sequences of the rickettsial gltA and ompA genes). A total of 84 ticks were collected from 8 individual hosts, as follows: Amblyomma pacae from 3 Cuniculus paca; Amblyomma ovale and Amblyomma coelebs from a Nasua narica; A. ovale from an Eira Barbara; A. ovale, Amblyomma cf. oblongoguttatum, and Ixodes affinis from a Puma concolor; and A. ovale, A. coelebs, A. cf. oblongoguttatum, and I. affinis from two Panthera onca. Three rickettsial agents were detected: Rickettsia amblyommii in A. pacae, Rickettsia sp. strain Atlantic rainforest in A. ovale, and Rickettsia sp. endosymbiont in Ixodes affinis. The present study provides unprecedented records of ticks harboring rickettsial agents in the New World. An emerging rickettsial pathogen of South America, Rickettsia sp. strain Atlantic rainforest, is reported for the first time in Central America. Besides expanding the distribution of 3 rickettsial agents in Central America, our results highlight the possible occurrence of Rickettsia sp. strain Atlantic rainforest-caused spotted fever human cases in Belize, since its possible
Špitalská, Eva; Boldiš, Vojtech; Mošanský, Ladislav; Sparagano, Olivier; Stanko, Michal
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.
May, Catherine E; Schulman, Martin L; Howell, Peter G; Lourens, Carina W; Gouws, Johan; Joone, Christopher; Monyai, Mpho S; le Grange, Misha; Bezuidt, Oliver K I; Harper, Cindy K; Guthrie, Alan J
Taylorella equigenitalis is the causative agent of contagious equine metritis (CEM), a sexually transmitted infection of horses. We report here the genome sequence of T. equigenitalis strain ERC_G2224, isolated in 2015 from a semen sample collected in 1996 from a Lipizzaner stallion in South Africa. Copyright © 2015 May et al.
Maina, Alice N; Luce-Fedrow, Alison; Omulo, Sylvia; Hang, Jun; Chan, Teik-Chye; Ade, Fredrick; Jima, Dereje D; Ogola, Eric; Ge, Hong; Breiman, Robert F; Njenga, Moses K; Richards, Allen L
A novel rickettsial agent, 'Candidatus Rickettsia asembonensis' strain NMRCiiT, was isolated from cat fleas, Ctenocephalides felis, from Kenya. Genotypic characterization of the new isolate based on sequence analysis of five rickettsial genes, rrs, gltA, ompA, ompB and sca4, indicated that this isolate clustered with Rickettsia felis URRWXCal2. The degree of nucleotide similarity demonstrated that isolate NMRCiiT belongs within the genus Rickettsia and fulfils the criteria for classification as a representative of a novel species. The name Rickettsia asembonensis sp. nov. is proposed, with NMRCiiT (=DSM 100172T=CDC CRIRC RAS001T=ATCC VR-1827T) as the type strain.
Blanda, Valeria; Torina, Alessandra; La Russa, Francesco; D'Agostino, Rosalia; Randazzo, Kety; Scimeca, Salvatore; Giudice, Elisabetta; Caracappa, Santo; Cascio, Antonio; de la Fuente, José
Rickettsiae (family Rickettsiaceae, order Rickettsiales) are obligate intracellular bacteria transmitted by arthropod vectors. Several Rickettsia species causing vector-borne rickettsioses belong to the spotted fever group (SFG). Traditionally, Rickettsia conorii has been considered as the main etiologic agent of Mediterranean spotted fever. However, the molecular characterization of rickettsiae allowed identifying other species involved in spotted fever in the Mediterranean region. In this study, 42 ticks collected from humans were subjected to morphological identification and molecular characterization of Rickettsia species potentially involved in human rickettsiosis in Sicily. Fourteen ticks positive to at least two Rickettsia spp. molecular markers were used in the study. Identified Rickettsia spp. included R. conorii, found in Rhipicephalus sanguineus sensu lato and Rhipicephalus turanicus, Rickettsia aeschlimannii found in Hyalomma marginatum, Hyalomma lusitanicum, Dermacentor marginatus and Ixodes ricinus, Rickettsia massiliae found in R. turanicus and R. sanguineus s.l., and Rickettsia slovaca found in D. marginatus and R. sanguineus s.l. Our results showed a great variety of zoonotic Rickettsia spp. in ticks collected from humans in Sicily. The Rickettsia spp. reported in this study were identified in previously recognized or new potential tick vectors in Europe, highlighting the risk of infection by different Rickettsia spp. for humans bitten by ticks in Sicily. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.
Coelho, Marcella Gonçalves; Ramos, Vanessa do Nascimento; Limongi, Jean Ezequiel; de Lemos, Elba Regina Sampaio; Guterres, Alexandro; da Costa Neto, Sócrates Fraga; Rozental, Tatiana; Bonvicino, Cibele Rodrigues; D'Andrea, Paulo Sérgio; Moraes-Filho, Jonas; Labruna, Marcelo Bahia; Szabó, Matias Pablo Juan
Sources of pathogenic Rickettsia in wildlife are largely unknown in Brazil. In this work, potential tick vectors and seroreactivity of small mammals against four spotted-fever group Rickettsia (R. rickettsii, R. parkeri, R. amblyommii and R. rhipicephali) and Rickettsia bellii from peri-urban areas of Uberlândia, a major town in Brazil, are described for the first time. Small mammals were captured and blood samples collected. Ticks were collected from the surface of the host and the environment and posteriorly identified. Reactivity of small mammal sera to Rickettsia was tested by indirect immunofluorescence assay (IFA) using crude antigens from five Brazilian Rickettsia isolates. Information was obtained from 416 small mammals (48 Marsupialia and 368 Rodentia). Forty-eight animals were parasitized and two tick species, Ixodes loricatus and Amblyomma dubitatum, were found on several host species, with a few tick-host relationships described for the first time. From the 416 tested sera, 70 reacted to at least one Rickettsia antigen (prevalence of 16.8%) and from these, 19 (27.1%) reacted to two or more antigens. Seroprevalence was higher for marsupials (39.6%) than for rodents (13.8%). Marsupial and Rhipidomys spp. sera reacted mainly (highest seroprevalence and titers) to R. bellii, and that of Necromys lasiurus mainly to R. rickettsii. Although the serologic assays poorly discriminate between closely related spotted-fever group Rickettsia, the observed small mammal seroreactivity suggests the circulation of Rickettsia in the peri-urban area of Uberlândia, albeit at low levels.
Lafri, Ismail; Leulmi, Hamza; Baziz-Neffah, Fadhila; Lalout, Reda; Mohamed, Chergui; Mohamed, Karakallah; Parola, Philippe; Bitam, Idir
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. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Ndeereh, David; Thaiyah, Andrew; Muchemi, Gerald; Miyunga, Antoinette A
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.
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.
Igolkina, Yana P; Rar, Vera A; Yakimenko, Valeriy V; Malkova, Marina G; Tancev, Aleksey K; Tikunov, Artem Yu; Epikhina, Tamara I; Tikunova, Nina V
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. Copyright © 2015 Elsevier B.V. All rights reserved.
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.
Vyas, Deven N; Kitchen, Andrew; Miró-Herrans, Aida T; Pearson, Laurel N; Al-Meeri, Ali; Mulligan, Connie J
Anatomically, modern humans are thought to have migrated out of Africa ∼60,000 years ago in the first successful global dispersal. This initial migration may have passed through Yemen, a region that has experienced multiple migrations events with Africa and Eurasia throughout human history. We use Bayesian phylogenetics to determine how ancient and recent migrations have shaped Yemeni mitogenomic variation. We sequenced 113 mitogenomes from multiple Yemeni regions with a focus on haplogroups M, N, and L3(xM,N) as these groups have the oldest evolutionary history outside of Africa. We performed Bayesian evolutionary analyses to generate time-measured phylogenies calibrated by Neanderthal and Denisovan mitogenomes in order to determine the age of Yemeni-specific clades. As defined by Yemeni monophyly, Yemeni in situ evolution is limited to the Holocene or latest Pleistocene (ages of clades in subhaplogroups L3b1a1a, L3h2, L3x1, M1a1f, M1a5, N1a1a3, and N1a3 range from 2 to 14 kya) and is often situated within broader Horn of Africa/southern Arabia in situ evolution (L3h2, L3x1, M1a1f, M1a5, and N1a1a3 ages range from 7 to 29 kya). Five subhaplogroups show no monophyly and are candidates for Holocene migration into Yemen (L0a2a2a, L3d1a1a, L3i2, M1a1b, and N1b1a). Yemeni mitogenomes are largely the product of Holocene migration, and subsequent in situ evolution, from Africa and western Eurasia. However, we hypothesize that recent population movements may obscure the genetic signature of more ancient migrations. Additional research, e.g., analyses of Yemeni nuclear genetic data, is needed to better reconstruct the complex population and migration histories associated with Out of Africa. © 2015 Wiley Periodicals, Inc.
Cheng, Cheng; Fu, Weiming; Ju, Wendong; Yang, Liwei; Xu, Ning; Wang, Yan-Mei; Li, Hui; Wang, Yan-Lu; Hu, Man-Xia; Wen, Jing; Jiao, Dan; Geng, Cong; Sun, Yi
In order to investigate the diversity of spotted fever group (SFG) Rickettsia infection in hard ticks, ticks were harvested from the forest areas in Suifenhe city, along the Chinese-Russian border and conventional PCR was carried out using universal SFG Rickettsia primers targeting gltA and ompA genes to screen for their infection with SFG Rickettsia organisms. Results showed that of the 215 ticks belonging to Ixodes persulcatus, Haemaphysalis concinna and Haemaphysalis japonica Warburton, 1908 species, 138 (64.2%) were positive for SFG Rickettsia. Three species of SFG Rickettsia were detected, Rickettsia raoultii, Rickettsia heilongjiangensis and Candidatus Rickettsia tarasevichiae. No co-infection with different species of SFG Rickettsia was found in any individual tick among the three tick species. We detected more than one SFG Rickettsia species in ticks from each of the three tick species with an overlapping distribution and potentially similar transmission cycles of SFG Rickettsia in the areas surveyed. Consequently, different pathogenic rickettsial species may be involved in human cases of rickettsiosis after a bite of the three above-mentioned tick species in that area Rickettsia. Copyright © 2016. Published by Elsevier GmbH.
Cordeiro, Matheus Dias; de Azevedo Baêta, Bruna; Cepeda, Patricia Barizon; Teixeira, Rafaella Câmara; Ribeiro, Carla Carolina Dias Uzedo; de Almeida Valim, Jaqueline Rodrigues; Pinter, Adriano; da Fonseca, Adivaldo Henrique
This study aimed to evaluate, by means of artificial feeding, the interaction between a pathogenic rickettsia and the hard tick R. microplus. We used partially engorged females fed on calves free of Rickettsia spp. Group 1 (G1), containing 20 ticks, was fed bovine blood only. Group 2 (G2), containing 20 ticks, was fed blood containing uninfected VERO cells, and group 3 (G3), containing 40 ticks, was fed blood containing VERO cells infected with Rickettsia parkeri. Biological parameters of the non-parasitic phase and a possible bacterial transmission to the tick eggs and to guinea pigs were evaluated. At the end of oviposition, all G3 females were PCR-positive for genes specific for the genus Rickettsia. Although no guinea pigs were infected, the experimental infection of R. microplus by R. parkeri caused a deleterious effect on the oviposition and provided the first report of transovarian transmission of rickettsia in this tick. Copyright © 2017 Elsevier GmbH. All rights reserved.
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
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.
Demkin, V.V.; Rydkina, E.B.; Likhoded, L.Ya.; Ignatovich, V.F.; Genig, V.A.; Balayeva, N.M.
Southern blot analysis of HindIII-cleaved rickettsial DNA was used for genotypic characterization of the typhus group (TG) species (R. prowazekii, R. typhi, R. canada) and a few species were of the spotted fever group (SFG)rickettsiae (R. sibirica, R. conorii, R. akari). Four different DNA probes were employed. PBH11 and PBH13 probes were morphospecific HindIII fragment of R prowazekii DNA. MW218 probe contained the gene for 51 K antigen and MW264 probe contained the citrate synthase gene of R. prowazekii. All the probes hybridized with the tested TG and SFG rickettsial DNAs, forming from 1 to 5 bands, but they did not with R. tsutsudamushi or C. burnetii DNAs. All the probes demonstrated specific hybridization pattern with TG species and R. akari. PBH11. PBH13 and MW264 probes clearly distinguished R. sibirica and R. conorii from the other tested rickettsiae, but not from each other. However, these two species differed slightly with MW218 probe. Several strains of each species were analyzed in this way and except for strains of R. conorii identical intra-species pattern were obtained. These data lead us to consider the obtained hybridization patterns as criteria for genotypic identification. (author)
Abdad, Mohammad Y; Abdallah, Rita Abou; Karkouri, Khalid El; Beye, Mamadou; Stenos, John; Owen, Helen; Unsworth, Nathan; Robertson, Ian; Blacksell, Stuart D; Nguyen, Thi-Tien; Nappez, Claude; Raoult, Didier; Fenwick, Stan; Fournier, Pierre-Edouard
A rickettsial organism harboured by Amblyomma triguttatum ticks on Barrow Island, Western Australia, was discovered after reports of possible rickettsiosis among local workers. Subsequent isolation of this rickettsia (strain BWI-1) in cell culture and analysis of its phylogenetic, genotypic and phenotypic relationships with type strains of Rickettsia species with standing in nomenclature suggested that it was sufficiently divergent to warrant its classification as a new species. Multiple gene comparison of strain BWI-1 revealed degrees of sequence similarity with Rickettsia raoultii, its closest relative, of 99.58, 98.89, 97.03, 96.93 and 95.73 % for the 16S rRNA, citrate synthase, ompA, ompB and sca4 genes, respectively. Serotyping in mice also demonstrated that strain BWI-1T was distinct from Rickettsia raoultii. Thus, we propose the naming of a new species, Rickettsia gravesii sp. nov., based on its novel genotypic and phenotypic characteristics. Strain BWI-1T was deposited in the ATCC, CSUR and ARRL collections under reference numbers VR-1664, CSUR R172 and RGBWI-1, respectively.
Kostopoulou, Vasiliki; Chochlakis, Dimosthenis; Kanta, Chrysoula; Katsanou, Andromachi; Rossiou, Konstantina; Rammos, Aidonis; Papadopoulos, Spyridon-Filippos; Katsarou, Theodora; Tselentis, Yannis; Psaroulaki, Anna; Boukas, Chrysostomos
Although tick-borne rickettsiosis is endemic in Greece, until recently, human samples arriving at the National Reference Centre under suspicion of rickettsial infection were routinely tested only for Rickettsia typhi and R. conorii. However, identification of additional rickettsia species in ticks prompted revision of the protocol in 2010. Until that year, all human samples received by the laboratory were tested for antibodies against R. conorii and R. typhi only. Now, tests for R. slovaca, R. felis, and R. mongolotimonae are all included in routine analysis. The current description of a human R. slovaca case is possible as a result of these changes in routine testing.
de Carvalho, Isabel Lopes; Milhano, Natacha; Santos, Ana Sofia; Almeida, Victor; Barros, Silvia C; De Sousa, Rita; Núncio, Maria Sofia
A total of 300 Ixodes ricinus ticks were tested by polymerase chain reaction (PCR) for the presence of Borrelia spp., Rickettsia spp., and Anaplasma phagocytophilum. Sequence analysis demonstrated 8 (2.7%) ticks infected with B. lusitaniae, 60 (20%) with Rickettsia spp., and 1 (0.3%) with A. phagocytophilum. Seven (2.3%) ticks were coinfected with B. lusitaniae and Rickettsia spp., 2 (0.6%) with R. monacensis, and 5 (1.7%) with Rickettsia sp. IRS3. The results of this study suggest simultaneous transmission of multiple tick-borne agents on Madeira Island, Portugal.
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.
Nyaga, Martin M; Stucker, Karla M; Esona, Mathew D; Jere, Khuzwayo C; Mwinyi, Bakari; Shonhai, Annie; Tsolenyanu, Enyonam; Mulindwa, Augustine; Chibumbya, Julia N; Adolfine, Hokororo; Halpin, Rebecca A; Roy, Sunando; Stockwell, Timothy B; Berejena, Chipo; Seheri, Mapaseka L; Mwenda, Jason M; Steele, A Duncan; Wentworth, David E; Mphahlele, M Jeffrey
Group A rotaviruses (RVAs) with distinct G and P genotype combinations have been reported globally. We report the genome composition and possible origin of seven G8P and five G2P human RVA strains based on the genetic evolution of all 11 genome segments at the nucleotide level. Twelve RVA ELISA positive stool samples collected in the representative countries of Eastern, Southern and West Africa during the 2007-2012 surveillance seasons were subjected to sequencing using the Ion Torrent PGM and Illumina MiSeq platforms. A reference-based assembly was performed using CLC Bio's clc_ref_assemble_long program, and full-genome consensus sequences were obtained. With the exception of the neutralising antigen, VP7, all study strains exhibited the DS-1-like genome constellation (P-I2-R2-C2-M2-A2-N2-T2-E2-H2) and clustered phylogenetically with reference strains having a DS-1-like genetic backbone. Comparison of the nucleotide and amino acid sequences with selected global cognate genome segments revealed nucleotide and amino acid sequence identities of 81.7-100 % and 90.6-100 %, respectively, with NSP4 gene segment showing the most diversity among the strains. Bayesian analyses of all gene sequences to estimate the time of divergence of the lineage indicated that divergence times ranged from 16 to 44 years, except for the NSP4 gene where the lineage seemed to arise in the more distant past at an estimated 203 years ago. However, the long-term effects of changes found within the NSP4 genome segment should be further explored, and thus we recommend continued whole-genome analyses from larger sample sets to determine the evolutionary mechanisms of the DS-1-like strains collected in Africa.
Eimanifar, Amin; Kimball, Rebecca T; Braun, Edward L; Ellis, James D
Apis mellifera capensis Eschscholtz and A.m. scutellata Lepeletier are subspecies of western honey bees that are indigenous to the Republic of South Africa (RSA). Both subspecies have invasive potential and are organisms of concern for areas outside their native range, though they are important bees to beekeepers, agriculture, and the environment where they are native. The aim of the present study was to examine genetic differentiation among these subspecies and estimate their phylogenetic relationships using complete mitochondrial genomes sequences. We used 25 individuals that were either assigned to one of the subspecies or designated hybrids using morphometric analyses. Phylogenetic analyses of mitogenome sequences by maximum likelihood (ML) and Bayesian inference identified a monophyletic RSA clade, subdivided into two clades. A haplotype network was consistent with the phylogenetic trees. However, members of both subspecies occurred in both clades, indicating that A.m. capensis and A.m. scutellata are neither reciprocally monophyletic nor do they exhibit paraphyly with one subspecies nested within the other subspecies. Furthermore, no mitogenomic features were diagnostic to either subspecies. All bees analyzed from the RSA expressed a substantial level of haplotype diversity (most samples had unique haplotypes) but limited nucleotide diversity. The number of variable codons across protein-coding genes (PCGs) differed among loci, with CO3 exhibiting the most variation and ATP6 the least.
Maganga, Gael D; Labouba, Ingrid; Ngoubangoye, Barthélémy; Nkili-Meyong, Andriniaina A; Obame Ondo, Daniel; Leroy, Eric M; Berthet, Nicolas
Canine distemper (CD) is the most deadly disease in dogs with mortality rates reaching 50%. The pathological agent, the CD virus (CDV), generally causes a severe systemic disease, although the nervous form can coexist with the acute catarrhal form in the same individual. In this study, we describe an outbreak of 18 cases of CD that occurred in 2015 in a German Shepherd dog population in northwestern Gabon. In addition, we determined the sequence of the CDV genotype associated with this fatal distemper infection in Gabon and compared it with other published CDV sequences. The CDV was detected using RT-PCR on cDNA from RNA of harvested brains and other organs. The identification was confirmed by sequencing amplicons. Moreover, we obtained the whole genome sequence using high-throughput sequencing. Phylogenetic analysis revealed that Gabonese CDV strain clustered with European strains belonging to the Europe genotype. This study provided the first molecular detection of the CDV strain associated with this fatal distemper infection in Central Africa region. Copyright © 2018 Elsevier B.V. All rights reserved.
Oliveira, Karla A.; Pinter, Adriano; Medina-Sanchez, Aaron; Boppana, Venkata D.; Wikel, Stephen K.; Saito, Tais B.; Shelite, Thomas; Blanton, Lucas; Popov, Vsevolod; Teel, Pete D.; Walker, David H.; Galvao, Marcio A.M.; Mafra, Claudio
Real-time PCR of Amblyomma imitator tick egg masses obtained in Nuevo Leon State, Mexico, identified a Rickettsia species. Sequence analyses of 17-kD common antigen and outer membrane protein A and B gene fragments showed to it to be R. rickettsii, which suggested a potential new vector for this bacterium. PMID:20678325
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.
These studies remarks that in addition to rats, other animals like cats, opossums and dogs could be implied in the transmission of Rickettsia typhi as infected fleas obtained from serologically positive animals have been detected in samples from endemic areas. In Mexico, the higher number of murine typhus cases have ...
Pennisi, Maria Grazia; Hofmann-Lehmann, Regina; Radford, Alan D; Tasker, Séverine; Belák, Sándor; Addie, Diane D; Boucraut-Baralon, Corine; Egberink, Herman; Frymus, Tadeusz; Gruffydd-Jones, Tim; Hartmann, Katrin; Horzinek, Marian C; Hosie, Margaret J; Lloret, Albert; Lutz, Hans; Marsilio, Fulvio; Thiry, Etienne; Truyen, Uwe; Möstl, Karin
OVERVIEW: Anaplasma species, Ehrlichia species and Rickettsia species are vector-borne pathogens infecting a wide variety of mammals, but causing disease in very few of them. Infection in cats: Anaplasma phagocytophilum is the most important feline pathogen among these rickettsial organisms, and
Angelakis, Emmanouil; Richet, Herve; Raoult, Didier
To further characterize human infections caused by Rickettsia sibirica mongolitimonae, we tested skin biopsy and swab samples and analyzed clinical, epidemiologic, and diagnostic characteristics of patients with a rickettsiosis. The most common (38%) indigenous species was R. sibirica mongolitimonae. Significantly more cases of R. sibirica mongolitimonae infection occurred during spring and summer.
Li, Yi-Han; Ahmed, Muhammad Z; Li, Shao-Jian; Lv, Ning; Shi, Pei-Qiong; Chen, Xiao-Sheng; Qiu, Bao-Li
A growing number of studies have revealed the presence of closely related endosymbionts in phylogenetically distant arthropods, indicating horizontal transmission of these bacteria. Here we investigated the interspecific horizontal transmission of Rickettsia between two globally invasive whitefly species, Bemisia tabaci MEAM1 and B. tabaci MED, via cotton plants. We found both scattered and confined distribution patterns of Rickettsia in these whiteflies. After entering cotton leaves, Rickettsia was restricted to the leaf phloem vessels and could be taken up by both species of the Rickettsia-free whitefly adults, but only the scattered pattern was observed in the recipient whiteflies. Both the relative quantity of Rickettsia and the efficiency of transmitting Rickettsia into cotton leaves were significantly higher in MEAM1 females than in MED females. The retention time of Rickettsia transmitted from MEAM1 into cotton leaves was at least 5 days longer than that of MED. Phylogenetic analysis based on 16S rRNA and gltA genes confirmed that the Rickettsia extracted from the donor MEAM1, the cotton leaves, the recipient MEAM1 and the recipient MED were all identical. We conclude that cotton plants can mediate horizontal transmission of Rickettsia between different insect species, and that the transmission dynamics of Rickettsia vary with different host whitefly species. © FEMS 2017. All rights reserved. For permissions, please e-mail: email@example.com.
Kuo, Chi-Chien; Shu, Pei-Yun; Mu, Jung-Jung; Lee, Pei-Lung; Wu, Yin-Wen; Chung, Chien-Kung; Wang, Hsi-Chieh
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. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Hajduskova, Eva; Literak, Ivan; Papousek, Ivo; Costa, Francisco B; Novakova, Marketa; Labruna, Marcelo B; Zdrazilova-Dubska, Lenka
A novel rickettsial sequence in the citrate synthase gltA gene indicating a novel Rickettsia species has been detected in 7 out of 4524 Ixodes ricinus ticks examined within several surveys performed in the Czech Republic from 2005 to 2009. This new Candidatus Rickettsia sp. sequence has been found in 2 nymphs feeding on wild birds (Luscinia megarhynchos and Erithacus rubecula), in a male tick from vegetation, and 4 ticks feeding on a dog (3 males, 1 female tick). Portions of the ompA, ompB, sca4, and htrA genes were not amplifiable in these samples. A maximum likelihood tree of rickettsiae based on comparisons of partial amino acid sequences of citrate synthase and nucleotide sequences of 16S rDNA genes and phylogenetic analysis revealed a basal position of the novel species in the proximity of R. bellii and R. canadensis. The novel species has been named 'Candidatus Rickettsia mendelii' after the founder of genetics, Gregor Mendel. Copyright © 2016 Elsevier GmbH. All rights reserved.
Novakova, Marketa; Costa, Francisco B; Krause, Frantisek; Literak, Ivan; Labruna, Marcelo B
Recently, a new rickettsia named 'Candidatus Rickettsia vini' belonging to the spotted fever group has been molecularly detected in Ixodes arboricola ticks in Spain, the Czech Republic, Slovakia and Turkey, with prevalence reaching up to 100 %. The aim of this study was to isolate this rickettsia in pure culture, and to describe it as a new Rickettsia species. A total of 148 ornitophilic nidicolous ticks Ixodes arboricola were collected in a forest near Breclav (Czech Republic) and examined for rickettsiae. Shell vial technique was applied to isolate rickettsiae in Vero cells. Rickettsial isolation was confirmed by optical microscopy and sequencing of partial sequences of the rickettsial genes gltA, ompA, ompB, and htrA. Laboratory guinea pigs and chickens were used for experimental infestations and infections. Animal blood sera were tested by immunofluorescence assay employing crude antigens of various rickettsiae. Rickettsia vini n. sp. was successfully isolated from three males of I. arboricola. Phylogenetic analysis of fragments of 1092, 590, 800, and 497 nucleotides of the gltA, ompA, ompB, and htrA genes, respectively, showed closest proximity of R. vini n. sp. to Rickettsia japonica and Rickettsia heilongjiangensis belonging to the spotted fever group. Experimental infection of guinea pigs and chickens with R. vini led to various levels of cross-reactions of R. vini-homologous antibodies with Rickettsia rickettsii, Rickettsia parkeri, 'Candidatus Rickettsia amblyommii', Rickettsia rhipicephali, Rickettsia bellii, and Rickettsia felis. Laboratory infestations by R. vini-infected I. arboricola larvae on chickens led to no seroconversion to R. vini n. sp., nor cross-reactions with R. rickettsii, R. parkeri, 'Ca. R. amblyommii', R. rhipicephali, R. bellii or R. felis. Our results suggest that R. vini n. sp. is possibly a tick endosymbiont, not pathogenic for guinea pigs and chickens. Regarding specific phenotypic characters and significant differences of DNA
Brown, T. A. (Terence A.)
... of genome expression and replication processes, and transcriptomics and proteomics. This text is richly illustrated with clear, easy-to-follow, full color diagrams, which are downloadable from the book's website...
Phan, Isabelle; Subramanian, Sandhya; Olsen, Christian; Edwards, Thomas E.; Guo, Wenjin; Zhang, Yang; Van Voorhis, Wesley C.; Stewart, Lance J.; Myler, Peter J.
Fumarate hydratase is an enzyme of the tricarboxylic acid cycle, one of the metabolic pathways characteristic of the mitochondria. The structure of R. prowazekii class II fumarate hydratase is reported at 2.4 Å resolution and is compared with the available structure of the human homolog. Rickettsiae are obligate intracellular parasites of eukaryotic cells that are the causative agents responsible for spotted fever and typhus. Their small genome (about 800 protein-coding genes) is highly conserved across species and has been postulated as the ancestor of the mitochondria. No genes that are required for glycolysis are found in the Rickettsia prowazekii or mitochondrial genomes, but a complete set of genes encoding components of the tricarboxylic acid cycle and the respiratory-chain complex is found in both. A 2.4 Å resolution crystal structure of R. prowazekii fumarate hydratase, an enzyme catalyzing the third step of the tricarboxylic acid cycle pathway that ultimately converts phosphoenolpyruvate into succinyl-CoA, has been solved. A structure alignment with human mitochondrial fumarate hydratase highlights the close similarity between R. prowazekii and mitochondrial enzymes
Riveron, Jacob M; Ibrahim, Sulaiman S; Mulamba, Charles; Djouaka, Rousseau; Irving, Helen; Wondji, Murielle J; Ishak, Intan H; Wondji, Charles S
Pyrethroid resistance in malaria vector, An. funestus is increasingly reported across Africa, threatening the sustainability of pyrethroid-based control interventions, including long lasting insecticidal nets (LLINs). Managing this problem requires understanding of the molecular basis of the resistance from different regions of the continent, to establish whether it is being driven by a single or independent selective events. Here, using a genome-wide transcription profiling of pyrethroid resistant populations from southern (Malawi), East (Uganda), and West Africa (Benin), we investigated the molecular basis of resistance, revealing strong differences between the different African regions. The duplicated cytochrome P450 genes ( CYP6P9a and CYP6P9b ) which were highly overexpressed in southern Africa are not the most upregulated in other regions, where other genes are more overexpressed, including GSTe2 in West (Benin) and CYP9K1 in East (Uganda). The lack of directional selection on both CYP6P9a and CYP6P9b in Uganda in contrast to southern Africa further supports the limited role of these genes outside southern Africa. However, other genes such as the P450 CYP9J11 are commonly overexpressed in all countries across Africa. Here, CYP9J11 is functionally characterized and shown to confer resistance to pyrethroids and moderate cross-resistance to carbamates (bendiocarb). The consistent overexpression of GSTe2 in Benin is coupled with a role of allelic variation at this gene as GAL4-UAS transgenic expression in Drosophila flies showed that the resistant 119F allele is highly efficient in conferring both DDT and permethrin resistance than the L119. The heterogeneity in the molecular basis of resistance and cross-resistance to insecticides in An. funestus populations throughout sub-Saharan African should be taken into account in designing resistance management strategies. Copyright © 2017 Riveron et al.
Riveron, Jacob M.; Ibrahim, Sulaiman S.; Mulamba, Charles; Djouaka, Rousseau; Irving, Helen; Wondji, Murielle J.; Ishak, Intan H.; Wondji, Charles S.
Pyrethroid resistance in malaria vector, An. funestus is increasingly reported across Africa, threatening the sustainability of pyrethroid-based control interventions, including long lasting insecticidal nets (LLINs). Managing this problem requires understanding of the molecular basis of the resistance from different regions of the continent, to establish whether it is being driven by a single or independent selective events. Here, using a genome-wide transcription profiling of pyrethroid resistant populations from southern (Malawi), East (Uganda), and West Africa (Benin), we investigated the molecular basis of resistance, revealing strong differences between the different African regions. The duplicated cytochrome P450 genes (CYP6P9a and CYP6P9b) which were highly overexpressed in southern Africa are not the most upregulated in other regions, where other genes are more overexpressed, including GSTe2 in West (Benin) and CYP9K1 in East (Uganda). The lack of directional selection on both CYP6P9a and CYP6P9b in Uganda in contrast to southern Africa further supports the limited role of these genes outside southern Africa. However, other genes such as the P450 CYP9J11 are commonly overexpressed in all countries across Africa. Here, CYP9J11 is functionally characterized and shown to confer resistance to pyrethroids and moderate cross-resistance to carbamates (bendiocarb). The consistent overexpression of GSTe2 in Benin is coupled with a role of allelic variation at this gene as GAL4-UAS transgenic expression in Drosophila flies showed that the resistant 119F allele is highly efficient in conferring both DDT and permethrin resistance than the L119. The heterogeneity in the molecular basis of resistance and cross-resistance to insecticides in An. funestus populations throughout sub-Saharan African should be taken into account in designing resistance management strategies. PMID:28428243
Lledó, Lourdes; Serrano, José Luis; Isabel Gegúndez, María; Giménez-Pardo, Consuelo; Saz, José Vicente
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.
Kurlovs, Andre H.; Li, Jinze; Cheng, Du; Zhong, Jianmin
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. PMID:25105893
Phan, Jimmy Ninh; Lu, Casey Roy; Bender, William Garrett; Smoak, Robert Marion
Abstract We amplified 16S rRNA, gltA, and ompA genes from Ixodes pacificus by polymerase chain reaction. Sequencing, BLAST analysis, and phylogenetic constructions indicated that two Rickettsia phylotypes are present in I. pacificus. While phylotype G021 has high homology to Ixodes scapularis endosymbiotic Rickettsia, phylotype G022 is a deeply branched novel spotted fever group Rickettsia. PMID:21413886
Sakamoto, Joyce M.; Azad, Abdu F.
Rickettsiae are obligate intracellular alphaproteobacteria that include pathogenic species in the spotted fever, typhus, and transitional groups. The development of a standardized cell line in which diverse rickettsiae can be grown and compared would be highly advantageous to investigate the differences among and between pathogenic and nonpathogenic species of rickettsiae. Although several rickettsial species have been grown in tick cells, tick cells are more difficult to maintain and they gr...
Harris, Emma K; Verhoeve, Victoria I; Banajee, Kaikhushroo H; Macaluso, Jacqueline A; Azad, Abdu F; Macaluso, Kevin R
The geographical overlap of multiple Rickettsia and tick species coincides with the molecular detection of a variety of rickettsial agents in what may be novel tick hosts. However, little is known concerning transmissibility of rickettsial species by various tick hosts. To examine the vertical transmission potential between select tick and rickettsial species, two sympatric species of ticks, Dermacentor variabilis and Amblyomma maculatum, were exposed to five different rickettsial species, including Rickettsia rickettsii, Rickettsia parkeri, Rickettsia montanensis, Rickettsia amblyommatis, or flea-borne Rickettsia felis. Fitness-related metrics including engorgement weight, egg production index, nutrient index, and egg hatch percentage were then assessed. Subsamples of egg clutches and unfed larvae, nymphs, and adults for each cohort were assessed for transovarial and transstadial transmission of rickettsiae by qPCR. Rickettsial exposure had a minimal fitness effect in D. variabilis and transovarial transmission was observed for all groups except R. rickettsii. In contrast, rickettsial exposure negatively influenced A. maculatum fitness and transovarial transmission of rickettsiae was demonstrated only for R. amblyommatis- and R. parkeri-exposed ticks. Sustained maintenance of rickettsiae via transstadial transmission was diminished from F 1 larvae to F 1 adults in both tick species. The findings of this study suggest transovarial transmission specificity may not be tick species dependent, and sustained vertical transmission is not common. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.
Full Text Available Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV and Ugandan cassava brown streak virus (UCBSV which are frequently found infecting cassava, one of sub-Saharan Africa's most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production.
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.
Eremeeva, Marina E; Dasch, Gregory A
Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. Once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. However, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vertebrate hosts or affecting humans. We have analyzed the key features of tick-borne maintenance of rickettsiae, which may provide a deeper basis for understanding those complex invertebrate interactions and strategies that have permitted survival and circulation of divergent rickettsiae in nature. Rickettsiae are found in association with a wide range of hard and soft ticks, which feed on very different species of large and small animals. Maintenance of rickettsiae in these vector systems is driven by both vertical and horizontal transmission strategies, but some species of Rickettsia are also known to cause detrimental effects on their arthropod vectors. Contrary to common belief, the role of vertebrate animal hosts in maintenance of rickettsiae is very incompletely understood. Some clearly play only the essential role of providing a blood meal to the tick while other hosts may supply crucial supplemental functions for effective agent transmission by the vectors. This review summarizes the importance of some recent findings with known and new vectors that afford an improved understanding of the eco-epidemiology of rickettsiae; the public health implications of that information for rickettsial diseases are also described. Special attention is paid to the co-circulation of different species and genotypes of rickettsiae within the same endemic areas and how these observations may influence, correctly or incorrectly, trends, and conclusions drawn from the surveillance of
Huang, Yuting; Zhao, Li; Zhang, Zhentang; Liu, Miaomiao; Xue, Zaifeng; Ma, Dongqiang; Sun, Xifeng; Sun, Yue; Zhou, Chuanmin; Qin, Xiangrong; Zhu, Yelei; Li, Wenqian; Yu, Hao; Yu, Xue-Jie
Leptotrombidium scutellare mites, the vector of Orientia tsutsugamushi, have rarely been reported to associate with Rickettsia species. Three hundred nineteen chiggers were collected from the ears of 32 rodents captured in Huangdao District of Qingdao City, China, in October 2015. The chigger samples were tested for Rickettsia, severe fever with thrombocytopenia syndrome virus, and hantavirus by PCR or RT-PCR amplification. All mites were classified morphologically and molecularly as L. scutellare chiggers. Rickettsial DNA sequences were amplified for four genes including 16S rRNA, ompB, gltA, and 17 kD protein genes. The minimum infection rate (MIR; number of positive pools/total specimens tested) of the Rickettsia species in the chiggers were 2.8% (9/319). Phylogenetic analysis indicated that individual genes were closely related to different Rickettsia species including R. felis (with 16S rRNA gene), R. australis (with gltA gene), an unnamed Rickettsia sp. TwKM02 (with ompB gene), and Rickettsia endosymbiont of soft tick Ornithodoros erraticus (with 17 kD protein gene). Phylogenic analysis of the concatenated sequence of 16S rRNA, gltA, ompB, and 17 kD protein genes indicated that the Rickettsia species from L. scutellare chigger was most closely related to R. australis and R. akari. These results indicated that the Rickettsia species in chiggers was unique; it was named Candidatus Rickettsia leptotrombidium. Severe fever with thrombocytopenia syndrome virus and hantavirus were not amplified from the chiggers, suggesting lack of infection of these pathogens in the chiggers. A unique Rickettsia species was detected in L. scutellare, which expanded the knowledge on the vector distribution of Rickettsia. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
McIntosh, Douglas; Bezerra, Rodrigo Alves; Luz, Hermes Ribeiro; Faccini, João Luiz Horacio; Gaiotto, Fernanda Amato; Giné, Gastón Andrés Fernandez; Albuquerque, George Rego
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.
Kubelová, M.; Papoušek, I.; Bělohlávek, T.; Goüy de Bellocq, Joëlle; Baird, Stuart J. E.; Široký, P.
Roč. 6, č. 6 (2015), s. 711-714 ISSN 1877-959X Institutional support: RVO:68081766 Keywords : Spotted fever group rickettsiae * Rickettsia monacensis * Rickettsia helvetica * Ixodes ricinus * Lacerta schreiberi Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.690, year: 2015
Koetsveld, Joris; Tijsse-Klasen, Ellen; Herremans, Tineke; Hovius, Joppe W. R.; Sprong, Hein
Only a few reported cases indicate that Rickettsia helvetica and Rickettsia monacensis can cause disease in humans. Exposure to these two spotted fever group (SFG) rickettsiae occurs through bites of Ixodes ricinus, also the primary vector of Lyme borreliosis in Europe. To date, it is unclear how
Development and Validation of an Improved PCR Method Using the 23S-5S Intergenic Spacer for Detection of Rickettsiae in Dermacentor variabilis Ticks and Tissue Samples from Humans and Laboratory Animals.
Kakumanu, Madhavi L; Ponnusamy, Loganathan; Sutton, Haley T; Meshnick, Steven R; Nicholson, William L; Apperson, Charles S
A novel nested PCR assay was developed to detectRickettsiaspp. in ticks and tissue samples from humans and laboratory animals. Primers were designed for the nested run to amplify a variable region of the 23S-5S intergenic spacer (IGS) ofRickettsiaspp. The newly designed primers were evaluated using genomic DNA from 11Rickettsiaspecies belonging to the spotted fever, typhus, and ancestral groups and, in parallel, compared to otherRickettsia-specific PCR targets (ompA,gltA, and the 17-kDa protein gene). The new 23S-5S IGS nested PCR assay amplified all 11Rickettsiaspp., but the assays employing other PCR targets did not. The novel nested assay was sensitive enough to detect one copy of a cloned 23S-5S IGS fragment from "CandidatusRickettsia amblyommii." Subsequently, the detection efficiency of the 23S-5S IGS nested assay was compared to those of the other three assays using genomic DNA extracted from 40 adultDermacentor variabilisticks. The nested 23S-5S IGS assay detectedRickettsiaDNA in 45% of the ticks, while the amplification rates of the other three assays ranged between 5 and 20%. The novel PCR assay was validated using clinical samples from humans and laboratory animals that were known to be infected with pathogenic species ofRickettsia The nested 23S-5S IGS PCR assay was coupled with reverse line blot hybridization with species-specific probes for high-throughput detection and simultaneous identification of the species ofRickettsiain the ticks. "CandidatusRickettsia amblyommii,"R. montanensis,R. felis, andR. belliiwere frequently identified species, along with some potentially novelRickettsiastrains that were closely related toR. belliiandR. conorii. Copyright © 2016 Kakumanu et al.
Lasecka-Dykes, Lidia; Wright, Caroline F.; Di Nardo, Antonello; Logan, Grace; Mioulet, Valerie; Jackson, Terry; Tuthill, Tobias J.; Knowles, Nick J.; King, Donald P.
Foot-and-mouth disease virus (FMDV) causes a highly contagious disease of cloven-hooved animals that poses a constant burden on farmers in endemic regions and threatens the livestock industries in disease-free countries. Despite the increased number of publicly available whole genome sequences, FMDV data are biased by the opportunistic nature of sampling. Since whole genomic sequences of Southern African Territories (SAT) are particularly underrepresented, this study sequenced 34 isolates from eastern and southern Africa. Phylogenetic analyses revealed two novel genotypes (that comprised 8/34 of these SAT isolates) which contained unusual 5′ untranslated and non-structural encoding regions. While recombination has occurred between these sequences, phylogeny violation analyses indicated that the high degree of sequence diversity for the novel SAT genotypes has not solely arisen from recombination events. Based on estimates of the timing of ancestral divergence, these data are interpreted as being representative of un-sampled FMDV isolates that have been subjected to geographical isolation within Africa by the effects of the Great African Rinderpest Pandemic (1887–1897), which caused a mass die-out of FMDV-susceptible hosts. These findings demonstrate that further sequencing of African FMDV isolates is likely to reveal more unusual genotypes and will allow for better understanding of natural variability and evolution of FMDV. PMID:29652800
Faccini-Martínez, Álvaro A; Márquez, Andrea C; Bravo-Estupiñan, Diana M; Calixto, Omar-Javier; López-Castillo, Christian A; Botero-García, Carlos A; Hidalgo, Marylin; Cuervo, Claudia
In 2015, we investigated Bartonella quintana and typhus group rickettsiae in body lice from homeless persons in Bogotá, Colombia. We found B. quintana-infected body lice and seroprevalence of this microorganism in 19% of homeless persons and typhus group rickettsiae in 56%. Public health professionals should start preemptive measures and active vector control.
Dermacentor reticulatus ticks from Poland were investigated by molecular methods for the presence of rickettsiae. During 2003/2004, a total of 285 adult ticks was assayed using primers RpCS.877 and RpCS.1258 derived from the citrate synthase (gltA) gene, and 116 samples (40.7%) were positive for rickettsial DNA. Ten out of these positive samples were further assayed using SLO1F and SLO1R primers derived form the rOmpA-encoding gene to confirm that detected rickettsiae belong to the spotted fever group (SFG). The obtained sequence of a fragment of the gltA gene of Rickettsia sp. isolated from Polish D. reticulatus demonstrated 96-98% similarities to Rickettsia slovaca, Rickettsia sibirica, Rickettsia honei, and other SFG rickettsiae. The nucleotide sequences of the amplified fragments of the ompA gene were 98% homologous to RpA4 Rickettsia sp. reported from ticks collected in territories of the former Soviet Union.
Eisenberg, G.H. Jr.; Osterman, J.V.; Stephenson, E.H.
Scrub thyphus immunogens that received inadequate gamma radiation contained residual, viable rickettsiae. The presence of these organisms in the host was masked by the rapid immune response elicited by the large number of inactivated rickettsiae. Transfer of homogenized spleen cells from immunized mice to normal syngeneic recipients provided a sensitive technique for the detection of these viable, replicating organisms
Silva, Arannadia Barbosa; Vizzoni, Vinicius Figueiredo; Costa, Andréa Pereira; Costa, Francisco Borges; Moraes-Filho, Jonas; Labruna, Marcelo Bahia; Gazêta, Gilberto Salles; de Maria Seabra Nogueira, Rita
The present study was performed in a non-endemic area for spotted fever (SF) in Imperatriz microregion, state of Maranhão, Brazil. Blood samples and ectoparasites were collected from 300 dogs of the Imperatriz microregion. Canine serum samples were tested individually by indirect immunofluorescence assay (IFA), using five Rickettsia isolates from Brazil. Antibodies reactive to at least one of the five species of Rickettsia were detected in 1.6% of the dogs (5/300). These sera were considered reactive to Rickettsia rickettsii and Rickettsia amblyommatis or very closely related species. The ticks (Acari: Ixodidae), identified as Rhipicephalus sanguineus sensu lato (Latreille), and the fleas, identified as Ctenocephalides felis, were tested by polymerase chain reaction (PCR) for detection of rickettsial DNA. More than 78% (83/106) of the C. felis fleas were found to be infected with Rickettsia species using gltA as rickettsial PCR targets, whereas no evidence of Rickettsia spp. was found in R. sanguineus s. l. Genetic analysis based on genes gltA, htrA and ompB showed that the detected strain, is most closely related to Rickettsia asembonensis (formerly Candidatus Rickettsia asemboensis). The present study is the first report of a R. asembonensis related infecting C. felis fleas in Brazil. Copyright © 2017 Elsevier B.V. All rights reserved.
Brumin, Marina; Levy, Maggie
The whitefly Bemisia tabaci is a cosmopolitan insect pest that harbors Portiera aleyrodidarum, the primary obligatory symbiotic bacterium, and several facultative secondary symbionts. Secondary symbionts in B. tabaci are generally associated with the bacteriome, ensuring their vertical transmission; however, Rickettsia is an exception and occupies most of the body cavity, except the bacteriome. The mode of Rickettsia transfer between generations and its subcellular localization in insect organs have not been investigated. Using electron and fluorescence microscopy, we show that Rickettsia infects the digestive, salivary, and reproductive organs of the insect; however, it was not observed in the bacteriome. Rickettsia invades the oocytes during early developmental stages and resides in follicular cells and cytoplasm; it is mostly excluded when the egg matures; however, some bacterial cells remain in the egg, ensuring their transfer to subsequent generations. Rickettsia was localized to testicles and the spermatheca, suggesting a horizontal transfer between males and females during mating. The bacterium was further observed at large amounts in midgut cells, concentrating in vacuole-like structures, and was located in the hemolymph, specifically at exceptionally large amounts around bacteriocytes and in fat bodies. Organs further infected by Rickettsia included the primary salivary glands and stylets, sites of possible secretion of the bacterium outside the whitefly body. The close association between Rickettsia and the B. tabaci digestive system might be important for digestive purposes. The vertical transmission of Rickettsia to subsequent generations occurs via the oocyte and not, like other secondary symbionts, the bacteriome. PMID:22660706
Prozorovskiy, S.V.; Alekseeva, N.V.; Knyazeva, E.N.; Ignatovich, V.F.; Barkhatova, O.T.
A modification of an immunoradiometric analysis to determine Rickettsia antigens in various biological substrates was studied, using rickettsious diagnostricums, egg and cell cultures of Rickettsia. The method was highly sensitive for the determination of minimal quantities of antigens in these substrates. The method appears to be promising for studies related to the detection of microorganisms and their antigens. 5 references.
Kuo, Chi-Chien; Shu, Pei-Yun; Mu, Jung-Jung
Abstract 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. PMID:25629776
Subramanian, Sandhya; Abendroth, Jan; Phan, Isabelle Q. H.; Olsen, Christian; Staker, Bart L.; Napuli, A.; Van Voorhis, Wesley C.; Stacy, Robin; Myler, Peter J.
The R. prowazekii 3-ketoacyl-(acyl-carrier-protein) reductase is similar to those from other prokaryotic pathogens but differs significantly from the mammalian orthologue, strengthening its case as a potential drug target. Rickettsia prowazekii, a parasitic Gram-negative bacterium, is in the second-highest biodefense category of pathogens of the National Institute of Allergy and Infectious Diseases, but only a handful of structures have been deposited in the PDB for this bacterium; to date, all of these have been solved by the SSGCID. Owing to its small genome (about 800 protein-coding genes), it relies on the host for many basic biosynthetic processes, hindering the identification of potential antipathogenic drug targets. However, like many bacteria and plants, its metabolism does depend upon the type II fatty-acid synthesis (FAS) pathway for lipogenesis, whereas the predominant form of fatty-acid biosynthesis in humans is via the type I pathway. Here, the structure of the third enzyme in the FAS pathway, 3-ketoacyl-(acyl-carrier-protein) reductase, is reported at a resolution of 2.25 Å. Its fold is highly similar to those of the existing structures from some well characterized pathogens, such as Mycobacterium tuberculosis and Burkholderia pseudomallei, but differs significantly from the analogous mammalian structure. Hence, drugs known to target the enzymes of pathogenic bacteria may serve as potential leads against Rickettsia, which is responsible for spotted fever and typhus and is found throughout the world
Kim, Yeon-Sook; Choi, Yeon-Joo; Lee, Kyung-Min; Ahn, Kyu-Joong; Kim, Heung-Chul; Klein, Terry; Jiang, Ju; Richards, Allen; Park, Kyung-Hee; Jang, Won-Jong
A Rickettsia sp. was isolated from the blood of a patient with an acute febrile illness using the shell vial technique; the isolate was named CN45Kr and was identified by molecular assay as Rickettsia monacensis, which was first recognized as a pathogen in Spain. Sequencing analysis showed that the gltA sequence of the isolate was identical to that of Rickettsia sp. IRS3. The ompA-5mp fragment sequence showed 100% identity to those of R. monacensis and Rickettsia sp. In56 and ompA-3pA In56 and 100% identity to that of Rickettsia sp. IRS3. The ompB sequence was found to have 99.9% similarity to that of R. monacensis IrR/Munich. This study confirms the pathogenicity of this agent and provides additional information about its geographic distribution. © 2017 The Societies and John Wiley & Sons Australia, Ltd.
de Vries, Jantina; Munung, Syntia Nchangwi; Matimba, Alice; McCurdy, Sheryl; Ouwe Missi Oukem-Boyer, Odile; Staunton, Ciara; Yakubu, Aminu; Tindana, Paulina
The introduction of genomics and biobanking methodologies to the African research context has also introduced novel ways of doing science, based on values of sharing and reuse of data and samples. This shift raises ethical challenges that need to be considered when research is reviewed by ethics committees, relating for instance to broad consent, the feedback of individual genetic findings, and regulation of secondary sample access and use. Yet existing ethics guidelines and regulations in Africa do not successfully regulate research based on sharing, causing confusion about what is allowed, where and when. In order to understand better the ethics regulatory landscape around genomic research and biobanking, we conducted a comprehensive analysis of existing ethics guidelines, policies and other similar sources. We sourced 30 ethics regulatory documents from 22 African countries. We used software that assists with qualitative data analysis to conduct a thematic analysis of these documents. Surprisingly considering how contentious broad consent is in Africa, we found that most countries allow the use of this consent model, with its use banned in only three of the countries we investigated. In a likely response to fears about exploitation, the export of samples outside of the continent is strictly regulated, sometimes in conjunction with regulations around international collaboration. We also found that whilst an essential and critical component of ensuring ethical best practice in genomics research relates to the governance framework that accompanies sample and data sharing, this was most sparingly covered in the guidelines. There is a need for ethics guidelines in African countries to be adapted to the changing science policy landscape, which increasingly supports principles of openness, storage, sharing and secondary use. Current guidelines are not pertinent to the ethical challenges that such a new orientation raises, and therefore fail to provide accurate guidance
Offerman, Kristy; Carulei, Olivia; van der Walt, Anelda Philine; Douglass, Nicola; Williamson, Anna-Lise
Two novel avipoxviruses from South Africa have been sequenced, one from a Feral Pigeon (Columba livia) (FeP2) and the other from an African penguin (Spheniscus demersus) (PEPV). We present a purpose-designed bioinformatics pipeline for analysis of next generation sequence data of avian poxviruses and compare the different avipoxviruses sequenced to date with specific emphasis on their evolution and gene content. The FeP2 (282 kbp) and PEPV (306 kbp) genomes encode 271 and 284 open reading frames respectively and are more closely related to one another (94.4%) than to either fowlpox virus (FWPV) (85.3% and 84.0% respectively) or Canarypox virus (CNPV) (62.0% and 63.4% respectively). Overall, FeP2, PEPV and FWPV have syntenic gene arrangements; however, major differences exist throughout their genomes. The most striking difference between FeP2 and the FWPV-like avipoxviruses is a large deletion of ~16 kbp from the central region of the genome of FeP2 deleting a cc-chemokine-like gene, two Variola virus B22R orthologues, an N1R/p28-like gene and a V-type Ig domain family gene. FeP2 and PEPV both encode orthologues of vaccinia virus C7L and Interleukin 10. PEPV contains a 77 amino acid long orthologue of Ubiquitin sharing 97% amino acid identity to human ubiquitin. The genome sequences of FeP2 and PEPV have greatly added to the limited repository of genomic information available for the Avipoxvirus genus. In the comparison of FeP2 and PEPV to existing sequences, FWPV and CNPV, we have established insights into African avipoxvirus evolution. Our data supports the independent evolution of these South African avipoxviruses from a common ancestral virus to FWPV and CNPV.
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.
Hanaoka, Nozomu; Matsutani, Minenosuke; Satoh, Masaaki; Ogawa, Motohiko; Shirai, Mutsunori; Ando, Shuji
We developed a novel loop-mediated isothermal amplification (LAMP) method to detect Rickettsia spp., including Rickettsia prowazekii and R. typhi. Species-specific LAMP primers were developed for orthologous genes conserved among Rickettsia spp. The selected modified primers could detect all the Rickettsia spp. tested. The LAMP method was successfully used to detect 100 DNA copies of Rickettsia spp. within approximately 60 min at 63℃. Therefore, this method may be an excellent tool for the early diagnosis of rickettsiosis in a laboratory or in the field.
Reyes-Centeno, Hugo; Ghirotto, Silvia; Détroit, Florent; Grimaud-Hervé, Dominique; Barbujani, Guido; Harvati, Katerina
Despite broad consensus on Africa as the main place of origin for anatomically modern humans, their dispersal pattern out of the continent continues to be intensely debated. In extant human populations, the observation of decreasing genetic and phenotypic diversity at increasing distances from sub-Saharan Africa has been interpreted as evidence for a single dispersal, accompanied by a series of founder effects. In such a scenario, modern human genetic and phenotypic variation was primarily generated through successive population bottlenecks and drift during a rapid worldwide expansion out of Africa in the Late Pleistocene. However, recent genetic studies, as well as accumulating archaeological and paleoanthropological evidence, challenge this parsimonious model. They suggest instead a "southern route" dispersal into Asia as early as the late Middle Pleistocene, followed by a separate dispersal into northern Eurasia. Here we test these competing out-of-Africa scenarios by modeling hypothetical geographical migration routes and assessing their correlation with neutral population differentiation, as measured by genetic polymorphisms and cranial shape variables of modern human populations from Africa and Asia. We show that both lines of evidence support a multiple-dispersals model in which Australo-Melanesian populations are relatively isolated descendants of an early dispersal, whereas other Asian populations are descended from, or highly admixed with, members of a subsequent migration event.
Rikihisa, Y.; Rota, T.; Lee, T.H.; MacDonald, A.B.; Ito, S.
The immunolabeling characteritics of Rickettsia tsutsugamushi (Gilliam strain) were examined by using a purified immunoglobulin G fraction of antibody to R. tsutsugamushi raised in rabbits. When rickettsiae in BHK-21 cells infected from yolk sac seed material were immunoferritin labeled, the binding of ferritin was found to be dense and uniform on the outer surface of the rickettsiae in disrupted host cells. Immunolabeling of purified suspensions of extracellular rickettsiae resulted in the uniform ferritin labeling of the microorganism. The immunoferritin labeling of R. tsutsugamushi during successive serial passages in BHK-21 cells revealed decreased labeling with each passage, and by the 10th passage there was no detectable labeling. However, these rickettsiae inoculated back into yolk sacs regained their immunoferritin labeling. Antibody against rickettsiae cultivated in BHK-21 cells continued labeling rickettsiae even after 9 serial passages in BHK-21 cells
Smith, D.K.; Winkler, H.H.
Intact Rickettsia prowazekii was radiolabeled with the glucose oxidase-lactoperoxidase method of iodination. Separation of the rickettsial extract into cytoplasmic, outer and inner membrane fractions demonstrated that the outer membrane was preferentially labeled. Analysis of the polypeptides of these fractions on high-resolution slab polyacrylamide gels showed that most of the 125 I was in polypeptide T49, an outer membrane constituent. Additional outer membrane polypeptides were iodinated in broken envelope preparations, demonstrating that T49 is uniquely accessible to the external environment and the asymmetric polypeptide organization of the outer membrane
Dundon, W.G.; Daojin, Y.; Loitsch, A.; Diallo, A.
This is the earliest PPRV genome sequenced to date and only the second lineage I virus available in public databases. The sequence provides important information to those working on the molecular evolution of this important transboundary disease.
Caspi-Fluger, Ayelet; Inbar, Moshe; Mozes-Daube, Netta; Katzir, Nurit; Portnoy, Vitaly; Belausov, Eduard; Hunter, Martha S.; Zchori-Fein, Einat
Bacteria in the genus Rickettsia, best known as vertebrate pathogens vectored by blood-feeding arthropods, can also be found in phytophagous insects. The presence of closely related bacterial symbionts in evolutionarily distant arthropod hosts presupposes a means of horizontal transmission, but no mechanism for this transmission has been described. Using a combination of experiments with live insects, molecular analyses and microscopy, we found that Rickettsia were transferred from an insect host (the whitefly Bemisia tabaci) to a plant, moved inside the phloem, and could be acquired by other whiteflies. In one experiment, Rickettsia was transferred from the whitefly host to leaves of cotton, basil and black nightshade, where the bacteria were restricted to the phloem cells of the plant. In another experiment, Rickettsia-free adult whiteflies, physically segregated but sharing a cotton leaf with Rickettsia-plus individuals, acquired the Rickettsia at a high rate. Plants can serve as a reservoir for horizontal transmission of Rickettsia, a mechanism which may explain the occurrence of phylogenetically similar symbionts among unrelated phytophagous insect species. This plant-mediated transmission route may also exist in other insect–symbiont systems and, since symbionts may play a critical role in the ecology and evolution of their hosts, serve as an immediate and powerful tool for accelerated evolution. PMID:22113034
Segura, Ferran; Pons, Immaculada; Pla, Júlia; Nogueras, María-Mercedes
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.
Sumrandee, Chalao; Baimai, Visut; Trinachartvanit, Wachareeporn; Ahantarig, Arunee
A total of 79 ticks collected from Sambar deer (Cervus unicolor), Barking deer (Muntiacus muntjak) and Wild boar (Sus scrofa) were examined by PCR for the presence of Rickettsia, Anaplasma, Coxiella, and Francisella bacteria. Of the 79 ticks, 13% tested positive for Rickettsia, 15% tested positive for Anaplasma, 4% tested positive for Coxiella, and 3% tested positive for Francisella. Interestingly, triple infection with Anaplasma, Rickettsia and Francisella was determined in a Dermacentor auratus tick. Moreover, another triple infection with Rickettsia, Anaplasma, and Coxiella was found in a Haemaphysalis lagrangei tick. Double infection of Rickettsia with Coxiella was also detected in another H. lagrangei tick. From the phylogenetic analyses, we found a Rickettsia sp. with a close evolutionary relationship to Rickettsia bellii in the H. lagrangei tick. We also found the first evidence of a Rickettsia sp. that is closely related to Rickettsia tamurae in Rhipicephalus (Boophilus) microplus ticks from Thailand. H. lagrangei and Haemaphysalis obesa ticks collected from Sambar deer tested positive for Anaplasma species form the same clade with Anaplasma bovis. In contrast, other H. lagrangei ticks collected from Sambar deer and D. auratus ticks collected from Wild boar were also reported for the first time to be infected with an Anaplasma species that is closely related to Anaplasma platys. The phylogenetic analysis of the 16S rRNA gene of Coxiella bacteria revealed that Coxiella symbionts from H. lagrangei formed a distinctly different lineage from Coxiella burnetii (a human pathogen). Additionally, Francisella bacteria identified in D. auratus ticks were found to be distantly related to a group of pathogenic Francisella species. The identification of these bacteria in several feeding ticks suggests the risk of various emerging tick-borne diseases and endosymbionts in humans, wildlife, and domestic animals in Thailand. Copyright © 2016 Elsevier GmbH. All rights
Trout Fryxell, R T; Steelman, C D; Szalanski, A L; Billingsley, P M; Williamson, P C
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. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
de Vries, Jantina; Williams, Thomas N; Bojang, Kalifa; Kwiatkowski, Dominic P; Fitzpatrick, Raymond; Parker, Michael
The practice of making datasets publicly available for use by the wider scientific community has become firmly integrated in genomic science. One significant gap in literature around data sharing concerns how it impacts on scientists' ability to preserve values and ethical standards that form an essential component of scientific collaborations. We conducted a qualitative sociological study examining the potential for harm to ethnic groups, and implications of such ethical concerns for data sharing. We focused our empirical work on the MalariaGEN Consortium, one of the first international collaborative genomics research projects in Africa. We conducted a study in three MalariaGEN project sites in Kenya, the Gambia, and the United Kingdom. The study entailed analysis of project documents and 49 semi-structured interviews with fieldworkers, researchers and ethics committee members. Concerns about how best to address the potential for harm to ethnic groups in MalariaGEN crystallised in discussions about the development of a data sharing policy. Particularly concerning for researchers was how best to manage the sharing of genomic data outside of the original collaboration. Within MalariaGEN, genomic data is accompanied by information about the locations of sample collection, the limitations of consent and ethics approval, and the values and relations that accompanied sample collection. For interviewees, this information and context were of important ethical value in safeguarding against harmful uses of data, but is not customarily shared with secondary data users. This challenged the ability of primary researchers to protect against harmful uses of 'their' data. We identified three protective mechanisms--trust, the existence of a shared morality, and detailed contextual understanding--which together might play an important role in preventing the use of genomic data in ways that could harm the ethnic groups included in the study. We suggest that the current practice of
Costa, Francisco B; da Costa, Andréa P; Moraes-Filho, Jonas; Martins, Thiago F; Soares, Herbert S; Ramirez, Diego G; Dias, Ricardo A; Labruna, Marcelo B
This study was performed in Maranhão state, a transition area two Brazilian biomes, Amazon and Cerrado. During 2011-2013, 1,560 domestic dogs were sampled for collection of serum blood samples and ticks in eight counties (3 within the Amazon and 5 within the Cerrado). A total of 959 ticks were collected on 150 dogs (9.6%). Rhipicephalus sanguineus sensu lato (s.l.) was the most abundant tick (68% of all collected specimens), followed by Amblyomma cajennense sensu lato (s.l.) (12.9%), Amblyomma parvum (9.2%), and Amblyomma ovale (5.2%). Other less abundant species (Rickettsia species: Rickettsia amblyommatis in 1% (1/100) A. cajennense s.l., 'Candidatus Rickettsia andeanae' in 20.7% (12/58) A. parvum, Rickettsia bellii in 6.8% (3/44) A. ovale and 100% (1/1) A. rotundatum ticks. An additional collection of A. sculptum from horses in a Cerrado area, and A. cajennense s.s. from pigs in an Amazon area revealed R. amblyommatis infecting only the A. cajennense s.s. ticks. Serological analysis of the 1,560 canine blood samples revealed 12.6% canine seroreactivity to Rickettsia spp., with the highest specific seroreactivity rate (10.2%) for R. amblyommatis. Endpoint titers to R. amblyommatis were significantly higher than those for the other Rickettsia antigens, suggesting that most of the seroreactive dogs were exposed to R. amblyommatis-infected ticks. Highest canine seroreactivity rates per locality (13.1-30.8%) were found in Amazon biome, where A. cajennense s.s. predominated. Lowest seroreactivity rates (1.9-6.5%) were found in Cerrado localities that were further from the Amazon, where A. sculptum predominated. Multivariate analyses revealed that canine seroreactivity to Rickettsia spp. or R. amblyommatis was statistically associated with rural dogs, exposed to Amblyomma ticks.
Medina-Sanchez, Aaron; Bouyer, Donald H; Alcantara-Rodriguez, Virginia; Mafra, Claudio; Zavala-Castro, Jorge; Whitworth, Ted; Popov, Vsevolod L; Fernandez-Salas, Ildefonso; Walker, David H
The state of Nuevo Leon, Mexico has had outbreaks of typhus group rickettsiosis, most recently recognized in 1997. Evaluation of the sera of 345 patients with a dengue-like illness revealed that 25.5% had antibodies reactive with typhus group rickettsiae and 16% had antibodies to Rickettsia parkeri. Rickettsiae were detected by PCR and shell-vial isolations in the field-collected Amblyomma ticks. Molecular characterization by DNA sequence analysis of the gltA, ompB, and 17-kDa gene identified the organisms to be R. prowazekii.
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.
The solution structure of the cold-shock-like protein from R. rickettsii, the causative agent of Rocky Mountain spotted fever, is reported. 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-strands 3 and 4, the solution structure of the R. rickettsii cold-shock-like protein has the typical Greek-key five-stranded β-barrel structure found in most cold-shock domains. Additionally, the R. rickettsii cold-shock-like protein, with a ΔG of unfolding of 18.4 kJ mol −1 , has a similar stability when compared with other bacterial cold-shock proteins
Speck, Stephanie; Kern, Tanja; Aistleitner, Karin; Dilcher, Meik; Dobler, Gerhard; Essbauer, Sandra
Rickettsia (R.) helvetica is the most prevalent rickettsia found in Ixodes ricinus ticks in Germany. Several studies reported antibodies against R. helvetica up to 12.5% in humans investigated, however, fulminant clinical cases are rare indicating a rather low pathogenicity compared to other rickettsiae. We investigated growth characteristics of R. helvetica isolate AS819 in two different eukaryotic cell lines with focus on ultra-structural changes of host cells during infection determined by confocal laser scanning microscopy. Further investigations included partially sequencing of rickA, sca4 and sca2 genes, which have been reported to encode proteins involved in cell-to-cell spread and virulence in some rickettsiae. R. helvetica grew constantly but slowly in both cell lines used. Confocal laser scanning microscopy revealed that the dissemination of R. helvetica AS819 in both cell lines was rather mediated by cell break-down and bacterial release than cell-to-cell spread. The cytoskeleton of both investigated eukaryotic cell lines was not altered. R. helvetica possesses rickA, but its expression is not sufficient to promote actin-based motility as demonstrated by confocal laser scanning microscopy. Hypothetical Sca2 and Sca4 proteins were deduced from nucleotide gene sequences but the predicted amino acid sequences were disrupted or truncated compared to other rickettsiae most likely resulting in non-functional proteins. Taken together, these results might give a first hint to the underlying causes of the reduced virulence and pathogenicity of R. helvetica.
Nyaga, Martin M; Jere, Khuzwayo C; Esona, Mathew D; Seheri, Mapaseka L; Stucker, Karla M; Halpin, Rebecca A; Akopov, Asmik; Stockwell, Timothy B; Peenze, Ina; Diop, Amadou; Ndiaye, Kader; Boula, Angeline; Maphalala, Gugu; Berejena, Chipo; Mwenda, Jason M; Steele, A Duncan; Wentworth, David E; Mphahlele, M Jeffrey
Group A rotaviruses (RVA) are among the main global causes of severe diarrhea in children under the age of 5years. Strain diversity, mixed infections and untypeable RVA strains are frequently reported in Africa. We analysed rotavirus-positive human stool samples (n=13) obtained from hospitalised children under the age of 5years who presented with acute gastroenteritis at sentinel hospital sites in six African countries, as well as bovine and porcine stool samples (n=1 each), to gain insights into rotavirus diversity and evolution. Polyacrylamide gel electrophoresis (PAGE) analysis and genotyping with G-(VP7) and P-specific (VP4) typing primers suggested that 13 of the 15 samples contained more than 11 segments and/or mixed G/P genotypes. Full-length amplicons for each segment were generated using RVA-specific primers and sequenced using the Ion Torrent and/or Illumina MiSeq next-generation sequencing platforms. Sequencing detected at least one segment in each sample for which duplicate sequences, often having distinct genotypes, existed. This supported and extended the PAGE and RT-PCR genotyping findings that suggested these samples were collected from individuals that had mixed rotavirus infections. The study reports the first porcine (MRC-DPRU1567) and bovine (MRC-DPRU3010) mixed infections. We also report a unique genome segment 9 (VP7), whose G9 genotype belongs to lineage VI and clusters with porcine reference strains. Previously, African G9 strains have all been in lineage III. Furthermore, additional RVA segments isolated from humans have a clear evolutionary relationship with porcine, bovine and ovine rotavirus sequences, indicating relatively recent interspecies transmission and reassortment. Thus, multiple RVA strains from sub-Saharan Africa are infecting mammalian hosts with unpredictable variations in their gene segment combinations. Whole-genome sequence analyses of mixed RVA strains underscore the considerable diversity of rotavirus sequences and
Szekeres, Sándor; Docters van Leeuwen, Arieke; Rigó, Krisztina; Jablonszky, Mónika; Majoros, Gábor; Sprong, Hein; Földvári, Gábor
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.
Rickettsia are arthropod-borne bacteria which have caused diseases that have had a military impact by sweeping through troops and incapacitating them, such as the so called Trench Fevers of World War I and II...
Winkler, H.H.; Miller, E.T.
L-929 cells were killed when approximately 50 viable Rickettsia prowazekii organisms per L-cell were centrifuged onto a monolayer. The glycerophospholipids of the L-cell were hydrolyzed to lysophosphatides and free fatty acids. Concomitantly, there was a loss of membrane integrity as shown by release of lactate dehydrogenase and 86Rb and permeability to trypan blue dye. No glycerophospholipid hydrolysis or cytotoxicity occurred when the rickettsiae were inactivated by heat, UV irradiation, N-ethylmaleimide, or metabolic inhibitors before their addition to the L-929 cells. On the other hand, treatment of the L929 cells with the cytoskeleton agents colchicine or cytochalasin B or with N-ethylmaleimide inhibited neither the phospholipase A activity nor the loss of membrane integrity. Cytochalasin B-treated cells could be damaged by even small numbers of rickettsiae. We suggest that this phospholipase A activity is used by the rickettsiae to escape from the phagosomes into the cytoplasm of host cells
Dittrich, Sabine; Rattanavong, Sayaphet; Lee, Sue J
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...
Blair, Patrick J; Jiang, Ju; Schoeler, George B; Moron, Cecilia; Anaya, Elizabeth; Cespedes, Manuel; Cruz, Christopher; Felices, Vidal; Guevara, Carolina; Mendoza, Leonardo; Villaseca, Pablo; Sumner, John W; Richards, Allen L; Olson, James G
... the focus of an outbreak of febrile disease in humans attributed, in part, to SFG rickettsia infections. Molecular identification of the etiologic agents from these samples was determined after partial sequencing of the 17-kDa common antigen gene...
Svendsen, Claus Bo; Milman, Nils; Nielsen, Henrik Winther
Rickettsia helvetica has previously been proposed as an aetiological agent in sarcoidosis. The purpose of the present study was to detect possible signs of Rickettsia infection in a Danish population of patients with sarcoidosis. Twenty-six patients with newly diagnosed sarcoidosis were...... interview. Evidence of rickettsial infection was assessed by an immunofluorescence assay testing for antibodies towards Rickettsia as well as specific real-time polymerase chain reaction (PCR) on lung biopsy specimens. We performed fluorescent in situ hybridization (FISH) on the biopsies to detect....... 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....
Svendsen, Claus Bo; Boye, Mette; Struve, Carsten
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......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...
Full Text Available Rickettsiosis is a potentially fatal tick borne disease. It is caused by the obligate intracellular bacteria Rickettsia, which is transferred to humans through salivary excretions of ticks during the biting process. Globally, the incidence of tick-borne diseases is increasing; as such, there is a need for a greater understanding of tick–host interactions to create more informed risk management strategies. Flinders Island spotted fever rickettsioses has been identified throughout Australia (Tasmania, South Australia, Queensland and Torres Strait Islands with possible identifications in Thailand, Sri Lanka and Italy. Flinders Island spotted fever is thought to be spread through tick bites and the reptile tick Bothriocroton hydrosauri has been implicated as a vector in this transmission. This study used qPCR to assay Bothriocroton hydrosauri ticks collected from Tiliqua rugosa (sleepy lizard hosts on mainland South Australia near where spotted fever cases have been identified. We report that, although we discovered Rickettsia in all tick samples, it was not Rickettsia honei. This study is the first to use PCR to positively identify Rickettsia from South Australian Bothriocroton hydrosauri ticks collected from Tiliqua rugosa (sleepy lizard hosts. These findings suggest that B. hydrosauri may be a vector of multiple Rickettsia spp. Also as all 41 tested B. hydrosauri ticks were positive for Rickettsia this indicates an extremely high prevalence within the studied area in South Australia.
Carl, M.; Robbins, F.; Hartzman, R.J.; Dasch, G.A.
Cytolytic human T cells clones generated in response to the intracellular bacterium Rickettsia typhi were characterized. Growing clones were tested for their ability to proliferate specifically in response to antigens derived from typhus group rickettsiae or to lyse targets infected with R. typhi or Rickettsia prowazekii, as measured by 51 Cr-release from target cells. Two clones were able to lyse targets infected with typhus group rickettsiae. One of these clones was more fully characterized because of its rapid growth characteristics. This cytolytic clone was capable of lysing an autologous infected target as well as a target matched for class I and II histocompatibility leukocyte antigens (HLA). It was not capable, however, of lysing either a target mismatched for both class I and II HLA or a target partially matched for class I HLA. In addition, the clone exhibited specificity in that it was able to lyse an autologous target infected with typhus group rickettsiae, but did not lyse an autologous target infected with an antigenically distinct rickettsial species, Rickettsia tsutsugamushi. These results demonstrate, for the first time, that cells infected with intracellular bacteria can be lysed by human cytotoxic T lymphocytes
Katargina, Olga; Geller, Julia; Ivanova, Anna; Värv, Kairi; Tefanova, Valentina; Vene, Sirkka; Lundkvist, Åke; Golovljova, Irina
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. Copyright © 2015 Elsevier GmbH. All rights reserved.
Cowdry, E V
In the absence of a satisfactory definition of Rickettsia the observations herein recorded were arbitrarily limited to bacterium-like organisms which are intracellular and Gram-negative. Rickettsia of this type were found in the following species: Amblyomma americana, Amblyomma hebraeum, Boophilus decoloratus, Atomus sp., Casinaria infesta, Chrysopa oculata, Ctenocephalus canis, Dermacentor variabilis, Lepisma saccharina, Lucoppia curviseta, Margaropus annulatus, Margaropus annulatus australis, Ornithodoros turicata, Pulex irritans, Rhipicephalus sanguineus, Rhipicephalus evertsi, and Salticus scenicus. Since intracellular, Gram-negative Rickettsia have been recorded in the literature as existing in Cimex lectularius, Dermacentor venustus, Melophagus ovinus, and Pediculus humanus, the occasional occurrence of such bodies must be conceded in the following groups not closely related phylogenetically: Attidae, Trombidiidae, Argasidae, lxodidae, Cinura, Acanthiidae, Pediculidae, Hippoboscidae, Chrysopidae, Pulicidae, and Ichneumonidae. The species which harbor Rickettsia differ widely in diet and habitat. One such species is insectivorous throughout life, two are insectivorous in larval stages, becoming vegetarian in the adult condition, one is chiefly vegetarian but partakes of some animal products, and two are usually entirely vegetarian; while the remainder subsist wholly upon a diet of mammalian blood. Rickettsia are associated, in only a few cases, with diseases in mammals. The evidence at hand does not lead beyond the conclusion that the Rickettsia mentioned above are true Gram-negative microorganisms, easily distinguishable from mitochondria and all other cytoplasmic and nuclear granulations, rather completely adapted to an intracellular existence, exhibiting in some cases a remarkable degree of host specificity, and often inherited through the eggs.
Keira A Cohen
Full Text Available The largest global outbreak of extensively drug-resistant (XDR tuberculosis (TB was identified in Tugela Ferry, KwaZulu-Natal (KZN, South Africa in 2005. The antecedents and timing of the emergence of drug resistance in this fatal epidemic XDR outbreak are unknown, and it is unclear whether drug resistance in this region continues to be driven by clonal spread or by the development of de novo resistance. A whole genome sequencing and drug susceptibility testing (DST was performed on 337 clinical isolates of Mycobacterium tuberculosis (M.tb collected in KZN from 2008 to 2013, in addition to three historical isolates, one of which was isolated during the Tugela Ferry outbreak. Using a variety of whole genome comparative approaches, 11 drug-resistant clones of M.tb circulating from 2008 to 2013 were identified, including a 50-member clone of XDR M.tb that was highly related to the Tugela Ferry XDR outbreak strain. It was calculated that the evolutionary trajectory from first-line drug resistance to XDR in this clone spanned more than four decades and began at the start of the antibiotic era. It was also observed that frequent de novo evolution of MDR and XDR was present, with 56 and 9 independent evolutions, respectively. Thus, ongoing amplification of drug-resistance in KwaZulu-Natal is driven by both clonal spread and de novo acquisition of resistance. In drug-resistant TB, isoniazid resistance was overwhelmingly the initial resistance mutation to be acquired, which would not be detected by current rapid molecular diagnostics that assess only rifampicin resistance.
de Sousa, Keyla Carstens Marques; Herrera, Heitor Miraglia; Rocha, Fabiana Lopes; Costa, Francisco Borges; Martins, Thiago Fernandes; Labruna, Marcelo Bahia; Machado, Rosangela Zacarias; André, Marcos Rogério
The genus Rickettsia comprises obligatory intracellular bacteria, well known to cause zoonotic diseases around the world. The present work aimed to investigate the occurrence of Rickettsia spp. in wild animals, domestic dogs and their respective ectoparasites in southern Pantanal region, central-western Brazil, by molecular and serological techniques. Between August 2013 and March 2015, serum, whole blood and/or spleen samples were collected from 31 coatis, 78 crab-eating foxes, seven ocelots, 42 dogs, 110 wild rodents, and 30 marsupials. Serum samples from canids, felids, rodents and marsupials were individually tested by indirect fluorescent antibody test (IFAT) in order to detect IgG antibodies to Rickettsia rickettsii, Rickettsia parkeri and Rickettsia amblyommatis. DNA samples from mammals and ectoparasites were submitted to a multiplex qPCR assay in order to detect and quantify spotted fever group (SFG) and typhus group (TG) rickettsiae and Orientia tsutsugamushi. Positive samples in qPCR assays were submitted to conventional PCR assays targeting gltA, ompA, ompB and htrA genes, followed by sequencing and phylogenetic analyses. The ticks collected (1582) from animals belonged to the species Amblyomma sculptum, Amblyomma parvum, Amblyomma ovale, Amblyomma tigrinum, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus sensu lato and Amblyomma auricularium. Overall, 27 (64.2%) dogs, 59 (75.6%) crab-eating foxes and six (85.7%) ocelots were seroreactive (titer≥64) to at least one Rickettsia species. For 17 (40.4%) dogs, 33 (42.3%) crab-eating foxes, and two (33.3%) ocelots, homologous reactions to R. amblyommatis or a closely related organism were suggested. One hundred and sixteen (23.5%) tick samples and one (1.2%) crab-eating fox blood sample showed positivity in qPCR assays for SFG Rickettsia spp. Among SFG Rickettsia-positive ticks samples, 93 (80.2%) belonged to A. parvum, 14 (12%) belonged to A. sculptum species, three (2.5%) belonged to A
Jun, Se-Ran; Leuze, Michael R.; Nookaew, Intawat
The 2014 Ebola outbreak in West Africa is the largest documented for this virus. To examine the dynamics of this genome, we compare more than 100 currently available ebolavirus genomes to each other and to other viral genomes. Based on oligomer frequency analysis, the family Filoviridae forms...
Tahir, Djamel; Socolovschi, Cristina; Marié, Jean-Lou; Ganay, Gautier; Berenger, Jean-Michel; Bompar, Jean-Michel; Blanchet, Denis; Cheuret, Marie; Mediannikov, Oleg; Raoult, Didier; Davoust, Bernard; Parola, Philippe
In French Guiana, located on the northeastern coast of South America, bats of different species are very numerous. The infection of bats and their ticks with zoonotic bacteria, especially Rickettsia species, is so far unknown. In order to improve knowledge of these zoonotic pathogens in this French overseas department, the presence and diversity of tick-borne bacteria was investigated with molecular tools in bat ticks. In the beginning of 2013, 32 bats were caught in Saint-Jean-du-Maroni, an area close to the coast of French Guiana, and the ticks of these animals were collected. A total of 354 larvae of Argasidae soft ticks (Ornithodoros hasei) from 12 bats (Noctilio albiventris) were collected and 107 of them were analysed. DNA was extracted from the samples and quantitative real-time PCR was carried out to detect Rickettsia spp., Bartonella spp., Borrelia spp. and Coxiella burnetii. All tested samples were negative for Bartonella spp., Borrelia spp. and Coxiella burnetii. Rickettsia DNA was detected in 31 (28.9%) ticks. An almost entire (1118 base pairs long) sequence of the gltA gene was obtained after the amplification of some positive samples on conventional PCR and sequencing. A Bayesian tree was constructed using concatenated rrs, gltA, ompA, ompB, and gene D sequences. The study of characteristic sequences shows that this Rickettsia species is very close (98.3-99.8%) genetically to R. peacockii. Nevertheless, the comparative analysis of sequences obtained from gltA, ompA, ompB, rrs and gene D fragments demonstrated that this Rickettsia is different from the other members of the spotted fever group. The sequences of this new species were deposited in GenBank as Candidatus Rickettsia wissemanii. This is the first report showing the presence of nucleic acid of Rickettsia in Ornithodoros hasei ticks from South American bats. Copyright © 2016 Elsevier GmbH. All rights reserved.
Znazen, Abir; Khrouf, Fatma; Elleuch, Nihel; Lahiani, Dorra; Marrekchi, Chakib; M'Ghirbi, Youmna; Ben Jemaa, Mounir; Bouattour, Ali; Hammami, Adnene
Rickettsioses are important remerging vector born infections. In Tunisia, many species have been described in humans and vectors. Genotyping is important for tracking pathogen movement between hosts and vectors. In this study, we characterized Rickettsia species detected in patients and vectors using multispacer typing (MST), proposed by Founier et al. and based on three intergenic spacers (dksA-xerC, rmpE- tRNA(fMet), mppA-pruC) sequencing. Our study included 25 patients hospitalized during 2009. Ticks and fleas were collected in the vicinity of confirmed cases. Serology was performed on serum samples by microimmunofluorescence using Rickettsia conorii and Rickettsia typhi antigens. To detect and identify Rickettsia species, PCR targeting ompA, ompB and gltA genes followed by sequencing was performed on 18 obtained skin biopsies and on all collected vectors. Rickettsia positive samples were further characterized using primers targeting three intergenic spacers (dksA-xerC, rmpE- tRNA(fMet) and mppA-purC). A rickettsial infection was confirmed in 15 cases (60%). Serology was positive in 13 cases (52%). PCR detected Rickettsia DNA in four biopsies (16%) allowing the identification of R. conorii subsp israelensis in three cases and R. conorii subsp conorii in one case. Among 380 collected ticks, nine presented positive PCR (2.4%) allowing the identification of six R. conorii subsp israelensis, two R. massiliae and one R. conorii subsp conorii. Among 322 collected fleas, only one was positive for R. felis. R. conorii subsp israelensis strains detected in humans and vectors clustered together and showed a new MST genotype. Similarly, R. conorii subsp conorii strains detected in a skin biopsy and a tick were genetically related and presented a new MST genotype. New Rickettsia spotted fever strain genotypes were found in Tunisia. Isolates detected in humans and vectors were genetically homogenous despite location differences in their original isolation suggesting
Jere, Khuzwayo C.; O'Neill, Hester G.; Potgieter, A. Christiaan; van Dijk, Alberdina A.
Rotavirus virus-like particles (RV-VLPs) are potential alternative non-live vaccine candidates due to their high immunogenicity. They mimic the natural conformation of native viral proteins but cannot replicate because they do not contain genomic material which makes them safe. To date, most RV-VLPs have been derived from cell culture adapted strains or common G1 and G3 rotaviruses that have been circulating in communities for some time. In this study, chimaeric RV-VLPs were generated from the consensus sequences of African rotaviruses (G2, G8, G9 or G12 strains associated with either P, P or P genotypes) characterised directly from human stool samples without prior adaptation of the wild type strains to cell culture. Codon-optimised sequences for insect cell expression of genome segments 2 (VP2), 4 (VP4), 6 (VP6) and 9 (VP7) were cloned into a modified pFASTBAC vector, which allowed simultaneous expression of up to four genes using the Bac-to-Bac Baculovirus Expression System (BEVS; Invitrogen). Several combinations of the genome segments originating from different field strains were cloned to produce double-layered RV-VLPs (dRV-VLP; VP2/6), triple-layered RV-VLPs (tRV-VLP; VP2/6/7 or VP2/6/7/4) and chimaeric tRV-VLPs. The RV-VLPs were produced by infecting Spodoptera frugiperda 9 and Trichoplusia ni cells with recombinant baculoviruses using multi-cistronic, dual co-infection and stepwise-infection expression strategies. The size and morphology of the RV-VLPs, as determined by transmission electron microscopy, revealed successful production of RV-VLPs. The novel approach of producing tRV-VLPs, by using the consensus insect cell codon-optimised nucleotide sequence derived from dsRNA extracted directly from clinical specimens, should speed-up vaccine research and development by by-passing the need to adapt rotaviruses to cell culture. Other problems associated with cell culture adaptation, such as possible changes in epitopes, can also be circumvented
Karpathy, Sandor E; Slater, Kimetha S; Goldsmith, Cynthia S; Nicholson, William L; Paddock, Christopher D
In 1973, investigators isolated a rickettsial organism, designated strain WB-8-2T, from an adult Amblyomma americanum tick collected at Land Between the Lakes National Recreation Area, TN, USA. This organism is now recognized as highly prevalent in A. americanum, as well as several other Amblyomma species found throughout the Western hemisphere. It has been suggested that cross-reactivity to WB-8-2T and similar strains contributes to the increasing number of spotted fever cases reported in the USA. In 1995, investigators provided preliminary evidence that this strain, as well as another strain from Missouri, represented a distinct taxonomic unit within the genus Rickettsia by evaluating sequences of the 16S rRNA and 17 kDa protein genes. However, the bacterium was never formally named, despite the use of the designation 'Rickettsia amblyommii' and later 'Candidatus Rickettsia amblyommii', for more than 20 years in the scientific literature. Herein, we provide additional molecular evidence to identify strain WB-8-2T as a representative strain of a unique rickettsial species and present a formal description for the species, with the proposed name modified to Rickettsia amblyommatis sp. nov. to conform to the International Code of Nomenclature of Prokaryotes. We also establish a pure culture of strain WB-8-2T and designate it as the type strain for the species. The type strain is WB-8-2T (=CRIRC RAM004T=CSURP2882T).
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
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
Full Text Available MeCab user dictionary for science technology term Rickettsia 名詞 一般 * * * * リケッチア属 リケッチアゾク リケッチアゾク Thesaurus2015 200906036464977172 C LS07 UNKNOWN_1 Rickettsia
Hendry, Tory A; Hunter, Martha S; Baltrus, David A
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. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
Monje, L D; Costa, F B; Colombo, V C; Labruna, M B; Antoniazzi, L R; Gamietea, I; Nava, S; Beldomenico, P M
Several cases of human rickettsiosis caused by Rickettsia parkeri were recently documented in the Paraná River delta of Argentina, where the tick vector is Amblyomma triste Koch. As cattle suffer recurrent A. triste infestations, they are at risk of becoming infected with R. parkeri Herein we investigated the dynamics of R. parkeri and its A. triste vector in a herd of beef cattle. Cattle were followed for 18 mo and samples were analyzed for the presence of antibodies against four Rickettsia species (R. parkeri, Rickettsia bellii, Rickettsia amblyommii, and Rickettsia felis) and also for the presence of rickettsial DNA. Additionally, cattle were examined for attached ticks and questing adult ticks were collected. All ticks were analyzed for the presence of rickettsial DNA. No evidence of rickettsemia was found in any cow, but the high R. parkeri infection rate documented in A. triste both questing in the study area (13.9%) and feeding on cattle (19.8%) and the identification of antibodies against R. parkeri antigen in 90% of cattle are evidence that infection is taking place. Altogether, our data suggest that A. triste ticks are capable of naturally exposing cattle to R. parkeri However, the progress of R. parkeri infection and its impact on bovine health and production remain to be established. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Carl, M.; Dasch, G.A.
The authors recently described a subset of OKT8, OKT3-positive lymphocytes from typhus-group rickettsia immune individuals which were capable of lysing autologous PHA-blasts or Epstein-Barr virus transformed B cells (LCL) infected with typhus-group rickettsiae. In order to determine if killing by these effectors was HLA-restricted, they stimulated peripheral blood mononuclear cells (PBMC) from typhus-group rickettsia immune individuals in vitro with typhus-group rickettsia-derived antigen for one week and then measured lysis of autologous LCL or HLA-mismatched LCL in a 4-6 hour Cr 51 -release assay. There was significant lysis of both the autologous and the HLA-mismatched infected targets as compared to the corresponding uninfected targets. Since this suggested that the effectors were lymphokine activated killers (LAK) rather than cytotoxic T lymphocytes, they then tested this hypothesis by stimulating PBMC from both immune and non-immune individuals in vitro for one week with purified interleukin 2 and measuring lysis of infected, autologous LCL. PBMC thus treated, from both immune and non-immune individuals, were capable of significantly lysing autologous, infected LCL as compared to the non-infected control. They therefore conclude that targets infected with typhus-group rickettsiae are susceptible to lysis to LAK
Luz, Hermes Ribeiro; McIntosh, Douglas; Furusawa, Guilherme P; Flausino, Walter; Rozental, Tatiana; Lemos, Elba R S; Landulfo, Gabriel A; Faccini, João Luiz H
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. Copyright © 2016 Elsevier GmbH. All rights reserved.
Dalva A. Portari Mancini
Full Text Available Foi realizada revisão da literatura com objetivo de atualizar as informações sobre a ocorrência de riquetsioses do grupo Rickettsia rickettsii. Verificou-se que nos EUA e Europa, a incidência da febre maculosa, vem aumentando desde 1970 até hoje. No Brasil, foi relatado um caso presuntivo, no estado da Bahia, em 1979. Com relação a prevenção, controle e tratamento dessa doença é salientada a importância de informações relacionadas com indivíduos expostos a picadas de carrapatos, notificação de novos casos, fatores ecológicos, técnicas laboratoriais mais específicas para a identificação do agente etiológico, e a antibioticoterapia mais eficiente. A vacinação é ainda referida como meio mais favorável na prevenção da doença, devendo ser administrada aos indivíduos de alto risco. No Brasil, faltam informações precisas sobre a ocorrência de R. rickettsii.A search of the literature to update the available information on the occurrence of rickettsiosis caused by the Rickettsia rickettsii group was made. It was verified that the incidence of spotted fever has had an increase in the U.S.A. and Europe since 1970. In Brazil, a presumptive case was reported in the State of Bahia, in 1979. Regarding the prevention, control and treatment of this disease, importance is given to data related to individuals exposed to tick bites, report of new cases, ecological factors, more specific laboratorial procedures for the identification of the etiological agent, and a more efficient antibiotic therapy. Vaccination is still regarded as the most adequate means for the prevention of the disease, and should be aimed at groups of individuals at high risk. In Brazil, there is a lack of more precise information on the occurrence of R. rickettsii.
Igolkina, Y; Bondarenko, E; Rar, V; Epikhina, T; Vysochina, N; Pukhovskaya, N; Tikunov, A; Ivanov, L; Golovljova, I; Ivanov, М; Tikunova, N
Rickettsia spp. are intracellular Gram-negative bacteria transmitted by arthropods. Two potentially pathogenic rickettsiae, Candidatus Rickettsia tarasevichiae and Rickettsia helvetica, have been found in unfed adult Ixodes persulcatus ticks. The aim of this study was to assess the prevalence and genetic variability of Rickettsia spp. in I. persulcatus ticks collected from different locations in the Russian Far East. In total, 604 adult I. persulcatus ticks collected from four sites in the Khabarovsk Territory (continental area) and one site in Sakhalin Island were examined for the presence of Rickettsia spp. by real-time PCR. Nested PCR with species-specific primers and sequencing were used for genotyping of revealed rickettsiae. The overall prevalence of Rickettsia spp. in ticks collected in different sites varied from 67.9 to 90.7%. However, the proportion of different Rickettsia species observed in ticks from Sakhalin Island significantly differed from that in ticks from the Khabarovsk Territory. In Sakhalin Island, R. helvetica prevailed in examined ticks, while Candidatus R. tarasevichiae was predominant in the Khabarovsk Territory. For gltA and ompB gene fragments, the sequences obtained for Candidatus R. tarasevichiae from all studied sites were identical to each other and to the known sequences of this species. According to sequence analysis of gltA, оmpB and sca4 genes, R. helvetica isolates from Sakhalin Island and the Khabarovsk Territory were identical to each other, but they differed from R. helvetica from other regions and from those found in other tick species. For the first time, DNA of pathogenic Rickettsia heilongjiangensis was detected in I. persulcatus ticks in two sites from the Khabarovsk Territory. The gltA, ompA and оmpB gene sequences of R. heilongjiangensis were identical to or had solitary mismatches with the corresponding sequences of R. heilongjiangensis found in other tick species. Copyright © 2016 Elsevier GmbH. All rights
Drost, W.T.; Berry, C.R.; Breitschwerdt, E.B.; Davidson, M.G.
Sixteen beagle dogs were injected intradermally with Rickettsia rickettsii. The dogs were divided into four groups (n = 4): 1) infected, non-treated control; 2) infected, treated with doxycycline; 3) infected, treated with doxycycline and an anti-inflammatory dose of corticosteroid; and 4) infected, treated with doxycycline and an immunosuppressive dose of corticosteroid. Thoracic radiographs were made and ocular fluorescein angiography was performed on days 6, 10, 17 post-inoculation. A mild interstitial lung opacity was noted in 4/16 dogs on day 6, 5/16 on day 10 and 3/16 on day 17 post-inoculation. Increased retinal vascular permeability was noted in 8/16 dogs on day 6, 3/16 on day 10 and 1/16 on day 17 post-inoculation. Correlation between the presence of radiographic and retinal lesions was not significant (p = 0.08). Eleven, naturally infected, dogs with thoracic radiographs and a final diagnosis of RMSF were also evaluated. Four of the 11 dogs had an unstructured interstitial pattern. Dogs with acute, experimentally-infected or naturally-occurring RMSF may have subtle pulmonary changes characterized by an unstructured interstitial pattern
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
Fernanda Silva Fortes
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
Blanton, Lucas S; Mendell, Nicole L; Walker, David H; Bouyer, Donald H
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.
Liu, Lijuan; Chen, Qian; Yang, Yu; Wang, Jiancheng; Cao, Xiaomei; Zhang, Sheng; Li, Hong; Hou, Yong; Wang, Fuxiang; Xu, Baoliang
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.
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.
Heinzen, R A; Grieshaber, S S; Van Kirk, L S; Devin, C J
Actin-based motility (ABM) is a virulence mechanism exploited by invasive bacterial pathogens in the genera Listeria, Shigella, and Rickettsia. Due to experimental constraints imposed by the lack of genetic tools and their obligate intracellular nature, little is known about rickettsial ABM relative to Listeria and Shigella ABM systems. In this study, we directly compared the dynamics and behavior of ABM of Rickettsia rickettsii and Listeria monocytogenes. A time-lapse video of moving intracellular bacteria was obtained by laser-scanning confocal microscopy of infected Vero cells synthesizing beta-actin coupled to green fluorescent protein (GFP). Analysis of time-lapse images demonstrated that R. rickettsii organisms move through the cell cytoplasm at an average rate of 4.8 +/- 0.6 micrometer/min (mean +/- standard deviation). This speed was 2.5 times slower than that of L. monocytogenes, which moved at an average rate of 12.0 +/- 3.1 micrometers/min. Although rickettsiae moved more slowly, the actin filaments comprising the actin comet tail were significantly more stable, with an average half-life approximately three times that of L. monocytogenes (100.6 +/- 19.2 s versus 33.0 +/- 7.6 s, respectively). The actin tail associated with intracytoplasmic rickettsiae remained stationary in the cytoplasm as the organism moved forward. In contrast, actin tails of rickettsiae trapped within the nucleus displayed dramatic movements. The observed phenotypic differences between the ABM of Listeria and Rickettsia may indicate fundamental differences in the mechanisms of actin recruitment and polymerization.
Eisawi, Nagwa M; Hassan, Dina A; Hussien, Mohammed O; Musa, Azza B; El Hussein, Abdel Rahim M
Spotted fever group (SFG) rickettsiosis is caused by obligatory intracellular Gram-negative bacteria that belong to the genus Rickettsia . Ticks belonging to the family Ixodidae can act as vectors, reservoirs or amplifiers of SFG rickettsiae. This study was conducted to estimate the seroprevalence of SFG rickettsioses in cattle, sheep and goats from Khartoum State, Sudan. Blood samples were collected from a total of 600 animals (sheep, goats and cattle) from 32 different farms distributed in three locations in Khartoum State during the period January to December 2012. Sera were tested for antibodies against SFG rickettsiae using IFAT. The prevalence of seropositivity was 59.3% in sheep, 60.1% in goats and 64.4% in cattle. Season was significantly ( P < 0.05) associated with seroprevalence of SFG rickettsiae in cattle during winter. The SFG rickettsiae antibodies prevalence was significantly higher in female compared with male in sheep, but there were no significant differences between male and female in either cattle or goats. The prevalence was significantly higher in adult animals compared with young in both sheep and goats. With regard to management system, there was a significant difference in the prevalence in cattle raised in closed system compared with those raised in semi-intensive system. In contrast, there was significant difference in the seroprevalence of SFG in sheep where the prevalence was higher in the sheep raised in semi-intensive system compared with those raised in close system. There was no significant difference in the seroprevalence in goats with regard to management systems. The unexpected high prevalence of SFG rickettsia antibodies in domestic ruminants sera suggest that the veterinary and public health impact of these agents in Sudan need further evaluation especially in humans.
Curto, Pedro; Simões, Isaura; Riley, Sean P; Martinez, Juan J
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
Polsomboon, Suppaluck; Hoel, David F; Murphy, Jittawadee R; Linton, Yvonne-Marie; Motoki, Maysa; Robbins, Richard G; Bautista, Kim; Bricen O, Ireneo; Achee, Nicole L; Grieco, John P; Ching, Wei-Mei; Chao, Chien-Chung
Little is known about tick-borne rickettsial pathogens in Belize, Central America. We tested ixodid ticks for the presence of Rickettsia species in three of the six northern and western Belizean districts. Ticks were collected from domestic animals and tick drags over vegetation in 23 different villages in November 2014, February 2015, and May 2015. A total of 2,506 collected ticks were identified to the following species: Dermacentor nitens Neumann (46.69%), Rhipicephalus sanguineus (Latreille) (19.55%), Rhipicephalus microplus (Canestrini) (19.47%), Amblyomma cajennense complex (9.74%), Amblyomma maculatum Koch (3.47%), Amblyomma ovale Koch (0.68%), Ixodes nr affinis (0.16%), Amblyomma nr maculatum (0.12%), and Amblyomma nr oblongoguttatum (0.12%). Ticks were pooled according to species, life stage (larva, nymph, or adult), and location (n = 509) for DNA extraction and screened for genus Rickettsia by quantitative real-time polymerase chain reaction (qPCR). All 42 positive pools were found to be positive for spotted fever group (SFG) Rickettsia in pools of A. cajennense complex (n = 33), A. maculatum (n = 4), A. nr maculatum (n = 1), A. ovale (n = 1), R. sanguineus (n = 1), and I. nr affinis (n = 2). Rickettsia amblyommatis was identified from A. cajennense complex and A. nr maculatum. Rickettsia parkeri was found in A. maculatum, and Rickettsia sp. endosymbiont was detected in I. nr affinis. The presence of infected ticks suggests a risk of tick-borne rickettsioses to humans and animals in Belize. This knowledge can contribute to an effective tick management and disease control program benefiting residents and travelers. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.
Banajee, Kaikhushroo H.; Embers, Monica E.; Langohr, Ingeborg M.; Doyle, Lara A.; Hasenkampf, Nicole R.; Macaluso, Kevin R.
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
Maina, Alice N; Klein, Terry A; Kim, Heung-Chul; Chong, Sung-Tae; Yang, Yu; Mullins, Kristin; Jiang, Ju; St John, Heidi; Jarman, Richard G; Hang, Jun; Richards, Allen L
Rickettsiae are associated with a diverse range of invertebrate hosts. Of these, mosquitoes could emerge as one of the most important vectors because of their ability to transmit significant numbers of pathogens and parasites throughout the world. Recent studies have implicated Anopheles gambiae as a potential vector of Rickettsia felis. Herein we report that a metagenome sequencing study identified rickettsial sequence reads in culicine mosquitoes from the Republic of Korea. The detected rickettsiae were characterized by a genus-specific quantitative real-time PCR assay and sequencing of rrs, gltA, 17kDa, ompB, and sca4 genes. Three novel rickettsial genotypes were detected (Rickettsia sp. A12.2646, Rickettsia sp. A12.2638 and Rickettsia sp. A12.3271), from Mansonia uniformis, Culex pipiens, and Aedes esoensis, respectively. The results underscore the need to determine the Rickettsia species diversity associated with mosquitoes, their evolution, distribution and pathogenic potential.
Svoboda, Petra; Dobler, Gerhard; Markotić, Alemka; Kurolt, Ivan-Christian; Speck, Stephanie; Habuš, Josipa; Vucelja, Marko; Krajinović, Lidija Cvetko; Tadin, Ante; Margaletić, Josip; Essbauer, Sandra
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.
Rees Robert L
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.
Panti-May, Jesús Alonso; Torres-Castro, Marco; Hernández-Betancourt, Silvia; Dzul-Rosado, Karla; Zavala-Castro, Jorge; López-Avila, Karina; Tello-Martín, Raúl
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.
Raulf, Marie-Kristin; Jordan, Daniela; Fingerle, Volker; Strube, Christina
In recent years, awareness of coinfections has increased as synergistic or antagonistic effects on interacting bacteria have been observed. To date, several reports on coinfections of ticks with Rickettsia and Borrelia spp. are available. However, associations are rarely described and studies are based on rather low sample sizes. In the present study, coinfections of Ixodes ricinus with these pathogens were investigated by determining their association in a meta-analysis. A total of 5079 tick samples examined for Rickettsia and Borrelia spp. via probe-based quantitative real-time PCR in previous prevalence studies or as submitted diagnostic material were included. In Borrelia-positive ticks, genospecies were determined by Reverse Line Blot. Determination of bacterial loads resulted in an increase between developmental tick stages with highest mean bacterial loads in female ticks (7.96×10 4 in Borrelia single-infected, 4.87×10 5 in Rickettsia single-infected and 3.22×10 5 in Borrelia-Rickettsia coinfected females). The determined Borrelia-Rickettsia tick coinfection rate was 12.3% (626/5079) with a significant difference to the expected coinfection rate of 9.0% (457/5079). A significant slight association as well as correlation between Borrelia and Rickettsia were determined. In addition, a significant interrelation of the bacterial load in coinfected ticks was shown. At the level of Borrelia genospecies, significant weak associations with Rickettsia spp. were detected for B. afzelii, B. garinii/bavariensis, B. valaisiana and B. lusitaniae. The positive association provides evidence for interactions between Borrelia and Rickettsia spp. in the tick vector, presumably resulting in higher bacterial replication rates in the tick vector and possibly the reservoir host. However, coinfection may impact the vector negatively as indicated by an absent increase in coinfection rates from nymphs to adults. Future studies are needed to investigate the underlying mechanisms of
Sebastian, Patrick S; Tarragona, Evelina L; Bottero, María N Saracho; Mangold, Atilio J; Mackenstedt, Ute; Nava, Santiago
The aim of this study was to get an overview about the occurrence of bacteria from the genus Ehrlichia and Rickettsia in ixodid ticks with medical importance in Argentina. Therefore, in 2013 and 2014, free-living ticks were collected in different provinces of northern Argentina. These ticks were determined as Amblyomma sculptum, Amblyomma neumanni, Amblyomma parvum, Amblyomma triste, Amblyomma ovale, Amblyomma tonelliae and Haemaphysalis juxtakochi. All samples were tested to determine the infection with Ehrlichia spp. and Rickettsia spp. by PCR assays. Rickettsial DNA was detected in all tested tick species, with the exception of A. tonelliae. 'Candidatus Rickettsia amblyommii', 'Candidatus Rickettsia andeanae', and Rickettsia parkeri were found in A. neumanni, A. parvum, and A. triste, respectively. Another rickettsial species, Rickettsia bellii, was found in A. sculptum, A. ovale and H. juxtakochi. None of the tested ticks showed infection with Ehrlichia. The results of the study demonstrate that Rickettsia species belonging to the spotted fever group are associated with various species of Amblyomma throughout a wide area of northern Argentina, where cases of Amblyomma ticks biting humans are common.
Nogueras, María-Mercedes; Pons, Immaculada; Ortuño, Anna; Lario, Sergio; Segura, Ferran
Rickettsia felis produces a syndrome indistinguishable from murine typhus, which has been described in Spain. R. felis is transmitted to humans by fleas. Although no clinical case has been described so far, serologic evidence of infections in humans, cats, and dogs has been obtained in our area. However, no study has been conducted regarding its presence in vectors. Recognition of routes of transmission is of great importance to prevent infection in humans. Taking into account these results, R. felis seems to be present in animals that are in contact with humans. The aim of this study was to determine the presence of R. felis in the fleas of cats and dogs from Northeast Spain, to show the presence of peridomestic cycle in our area. Between May 2006 and July 2008, 78 fleas were collected. Sixty-three fleas were recovered from kennels. Most of them were collected from cages and a few of them on dogs and cats living in kennels. Fifteen fleas were collected from dogs and cats attended at a veterinary clinic. Fleas were rinsed with ethanol, dried, identified, and stored at 4°C. DNA was extracted from each flea individually. Rickettsial DNA was determined by quantitative real-time polymerase chain reaction. OmpB-specific primers and molecular beacon probes targeting specifically R. felis were used. All 78 fleas were identified as Ctenocephalides felis. R. felis was detected in 34 (43.6%) fleas. No nucleic acids were amplified from negative controls and expected results were obtained from positive controls. Eight positive samples were also confirmed by sequencing. R. felis was found in a high percentage of Ct. felis from cats and dogs. It seems that there is a peridomestic cycle in Northeast Spain, which would allow contact of R. felis with humans.
Rickettsia sp. strain colombianensi (Rickettsiales: Rickettsiaceae): a new proposed Rickettsia detected in Amblyomma dissimile (Acari: Ixodidae) from iguanas and free-living larvae ticks from vegetation.
Miranda, Jorge; Portillo, Aránzazu; Oteo, José A; Mattar, Salim
From January to December 2009, 55 Amblyomma dissimile (Koch) ticks removed from iguanas in the municipality of Monteria and 3,114 ticks [458 Amblyomma sp. larvae, 2,636 Rhipicephalus microplus (Canestrini) larvae and 20 Amblyomma sp. nymphs] collected over vegetation in Los Cordobas were included in the study. The ticks were pooled into groups from which DNA was extracted. For initial screening of Rickettsia sp., each pool was analyzed by gltA real-time polymerase chain reaction (PCR). Positive pools were further studied using gltA, ompA, and ompB conventional PCR assays. Sequencing and phylogenetic analysis were also conducted. Rickettsial DNA was found in 28 pools of ticks (16 A. dissimile pools and 12 free-living larvae pools) out of 113 (24.7%) using real-time PCR. The same 28 pools were also positive using conventional PCR assays aimed to amplify gltA, ompA, and ompB. For each gene analyzed, PCR products obtained from 4/28 pools (two pools of A. dissimile, one pool of Amblyomma sp. larvae and one pool of Rh. microplus larvae) were randomly chosen and sequenced twice. Nucleotide sequences generated were identical to each other for each of the rickettsial genes gltA, ompA, and ompB, and showed 99.4, 95.6, and 96.4% identity with those of Rickettsia tamurae. They were deposited in the GenBank database under accession numbers JF905456, JF905458, and JF905457, respectively. In conclusion, we present the first molecular evidence of a novel Rickettsia (Rickettsia sp. strain Colombianensi) infecting A. dissimile ticks collected from iguanas, and also Rh. microplus and unspeciated Amblyomma larvae from vegetation in Colombia.
0279276E-D761-4A27-BFF7-7329E05E0F66 Infection of the Gulf Coast tick, Amblyomma maculatum (Acari: Ixodidae), with Rickettsia parkeri: first report from...Spring, MD 20910-1230, U.S.A. Abstract The molecular detection of Rickettsia parkeri in a Gulf Coast tick, Amblyomma maculatum, collected in Delaware...near Smyrna, Delaware. All specimens were tested for the presence of Rickettsia with a genus-specific quantitative real-time polymerase chain
Maurício C Horta
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.
Sumrandee, C.; Hirunkanokpun, S.; Doornbos, K.; Kitthawee, S.; Baimai, V.; Grubhoffer, Libor; Trinachartvanit, W.; Ahantarig, A.
Roč. 5, č. 6 (2014), s. 632-640 ISSN 1877-959X Institutional support: RVO:60077344 Keywords : Tick * Rickettsia spp. * Amblyomma varanense * Amblyomma helvolum * Snake * Thailand Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.718, year: 2014
Ogrzewalska, M.; Literák, I.; Cárdenas-Callirgos, J. M.; Čapek, Miroslav; Labruna, M. B.
Roč. 3, č. 4 (2012), s. 254-256 ISSN 1877-959X R&D Projects: GA AV ČR IAA601690901; GA MŠk LC06073 Institutional support: RVO:68081766 Keywords : Rickettsia bellii * ticks * Amblyomma calcaratum * birds * Peru Subject RIV: EG - Zoology Impact factor: 2.353, year: 2012
Duscher, G. G.; Hodžić, A.; Weiler, M.; Vaux, A. G. C.; Rudolf, Ivo; Sixl, W.; Medlock, J. M.; Versteirt, V.; Hubálek, Zdeněk
Roč. 7, č. 5 (2016), s. 720-722 ISSN 1877-959X Institutional support: RVO:68081766 Keywords : Rickettsia raoultii * Dermacentor reticulatus * TIBOLA * DEBONEL * Austria Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 3.230, year: 2016
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.
Raczniak, Gregory A.; Kato, Cecilia; Chung, Ida H.; Austin, Amy; McQuiston, Jennifer H.; Weis, Erica; Levy, Craig; Carvalho, Maria da Gloria S.; Mitchell, Audrey; Bjork, Adam; Regan, Joanna J.
Rocky Mountain spotted fever, a tick-borne disease caused by Rickettsia rickettsii, is challenging to diagnose and rapidly fatal if not treated. We describe a decedent who was co-infected with group A β-hemolytic streptococcus and R. rickettsii. Fatal cases of Rocky Mountain spotted fever may be underreported because they present as difficult to diagnose co-infections. PMID:25331804
Kim B. Madsen
Full Text Available Vector-borne diseases such as Lyme borreliosis and rickettsioses have been associated with ocular inflammation. Our aim was to study patients with diagnosed uveitis to evaluate serological signs of infection or exposure to these tick-borne agents. Forty-eight patients were prospectively examined with serology together with medical records and a questionnaire concerning previous exposure, diseases, and treatments. Seven patients (14.6% showed seroconversion to Rickettsia spp. between acute and convalescent phase sera, which provides support for a positive Rickettsia diagnosis according to guidelines. The specificity was confirmed by Western blot. Additional 28 patients had stationary titres of which eight (16.6% had 1 : 256 or higher titre in the first serum, and another 13 patients were seronegative. No epidemiological risk factor or marker could be identified. For Borrelia, only three patients showed moderate IgG titres. A control group of 100 blood donors, 60 patients with rheumatic disease, and 56 patients seeking medical care were tested of which 2.0–7.1% showed low anti-Rickettsia titres and 3.0–8.3% anti-Borrelia titres. The findings are indicative for an association between infection or exposure to Rickettsia spp. and uveitis with a seropositivity among patients with recurrent uveitis in concordance with the spread of rickettsial exposure in a tick-exposed population.
Madsen, Kim B.; Wallménius, Katarina; Fridman, Åke; Påhlson, Carl
Vector-borne diseases such as Lyme borreliosis and rickettsioses have been associated with ocular inflammation. Our aim was to study patients with diagnosed uveitis to evaluate serological signs of infection or exposure to these tick-borne agents. Forty-eight patients were prospectively examined with serology together with medical records and a questionnaire concerning previous exposure, diseases, and treatments. Seven patients (14.6%) showed seroconversion to Rickettsia spp. between acute and convalescent phase sera, which provides support for a positive Rickettsia diagnosis according to guidelines. The specificity was confirmed by Western blot. Additional 28 patients had stationary titres of which eight (16.6%) had 1 : 256 or higher titre in the first serum, and another 13 patients were seronegative. No epidemiological risk factor or marker could be identified. For Borrelia, only three patients showed moderate IgG titres. A control group of 100 blood donors, 60 patients with rheumatic disease, and 56 patients seeking medical care were tested of which 2.0–7.1% showed low anti-Rickettsia titres and 3.0–8.3% anti-Borrelia titres. The findings are indicative for an association between infection or exposure to Rickettsia spp. and uveitis with a seropositivity among patients with recurrent uveitis in concordance with the spread of rickettsial exposure in a tick-exposed population. PMID:29318041
Jiang, Ju; Blair, Patrick J; Felices, Vidal; Moron, Cecilia; Cespedes, Manuel; Anaya, Elizabeth; Schoeler, George B; Sumner, John W; Olson, James G; Richards, Allen L
... (SFG) rickettsia. Following nested polymerase chain reaction (PCR) amplification of the 17-kDa gene, gltA, ompB, ompA, and sca4, amplicons were purified, sequenced, and compared to those downloaded from GenBank...
Hecht, Joy A; Allerdice, Michelle E J; Krawczak, Felipe S; Labruna, Marcelo B; Paddock, Christopher D; Karpathy, Sandor E
Rickettsia bellii is a rickettsial species of unknown pathogenicity that infects argasid and ixodid ticks throughout the Americas. Many molecular assays used to detect spotted fever group (SFG) Rickettsia species do not detect R. bellii, so that infection with this bacterium may be concealed in tick populations when assays are used that screen specifically for SFG rickettsiae. We describe the development and validation of a R. bellii-specific, quantitative, real-time PCR TaqMan assay that targets a segment of the citrate synthase (gltA) gene. The specificity of this assay was validated against a panel of DNA samples that included 26 species of Rickettsia, Orientia, Ehrlichia, Anaplasma, and Bartonella, five samples of tick and human DNA, and DNA from 20 isolates of R. bellii, including 11 from North America and nine from South America. A R. bellii control plasmid was constructed, and serial dilutions of the plasmid were used to determine the limit of detection of the assay to be one copy per 4 µl of template DNA. This assay can be used to better determine the role of R. bellii in the epidemiology of tick-borne rickettsioses in the Western Hemisphere. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.
Gajda, Ewa; Hildebrand, Joanna; Sprong, Hein; Buńkowska-Gawlik, Katarzyna; Perec-Matysiak, Agnieszka; Coipan, Elena Claudia
Rickettsiae are obligate intracellular alpha-proteobacteria. They are transmitted via arthropod vectors, which transmit the bacteria between animals and occasionally to humans. So far, much research has been conducted to indicate reservoir hosts for these microorganisms, but our knowledge is still
Yssouf, Amina; Almeras, Lionel; Terras, Jérôme; Socolovschi, Cristina; Raoult, Didier; Parola, Philippe
Background Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has been shown to be an effective tool for the rapid identification of arthropods, including tick vectors of human diseases. Methodology/Principal Findings The objective of the present study was to evaluate the use of MALDI-TOF MS to identify tick species, and to determine the presence of rickettsia pathogens in the infected Ticks. Rhipicephalus sanguineus and Dermacentor marginatus Ticks infected or not by R. conorii conorii or R. slovaca, respectively, were used as experimental models. The MS profiles generated from protein extracts prepared from tick legs exhibited mass peaks that distinguished the infected and uninfected Ticks, and successfully discriminated the Rickettsia spp. A blind test was performed using Ticks that were laboratory-reared, collected in the field or removed from patients and infected or not by Rickettsia spp. A query against our in-lab arthropod MS reference database revealed that the species and infection status of all Ticks were correctly identified at the species and infection status levels. Conclusions/Significance Taken together, the present work demonstrates the utility of MALDI-TOF MS for a dual identification of tick species and intracellular bacteria. Therefore, MALDI-TOF MS is a relevant tool for the accurate detection of Rickettsia spp in Ticks for both field monitoring and entomological diagnosis. The present work offers new perspectives for the monitoring of other vector borne diseases that present public health concerns. PMID:25659152
Palomar, Ana M; Cevidanes, Aitor; Portillo, Aránzazu; Kalema-Zikusoka, Gladis; Chirife, Andrea D; Romero, Lourdes; Muro, Jesús; Mugisha, Lawrence; Oteo, José A; Millán, Javier
Fleas are known vectors of zoonotic agents. Thirty-five fleas, including 28 Ctenocephalides felis (Bouché), four Pulex irritans (L.), and three Echidnophaga gallinacea (Westwood) from 19 rural dogs from southwestern Uganda were analyzed for the presence of Rickettsia spp. (ompB, gltA, and 17 kDa fragment genes) and Bartonella spp. (rpoB and ITS genes) by PCR. Rickettsial DNA was detected in 27 out of 28 of Ct. felis and in two out of four P. irritans. None of the E. gallinacea specimens harbored Rickettsia DNA. Rickettsia felis was confirmed in 12 Ct. felis and in the two P. irritans specimens with positive PCR-results. In addition, the presence of Candidatus Rickettsia asemboensis was evidenced in 15 Ct. felis. Bartonella spp. was not amplified in any sample. Our survey indicates that R. felis, the agent of the flea-borne spotted fever, is present in the study area. Besides, this is the first description of Ca. R. asemboensis in Uganda. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Schou, Kirstine Klitgaard; Chriél, Mariann; Isbrand, Anastasia
From a migrating golden jackal (Canis aureus), we retrieved 21 live male Dermacentor reticulatus ticks, a species not previously reported from wildlife in Denmark. We identified Rickettsia raoultii from 18 (86%) of the ticks. This bacterium is associated with scalp eschar and neck lymphadenopathy...
Skarphédinsson, Sigurdur; Lyholm, Birgitte Fjendbo; Ljungberg, Marianne
% 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...
Ogrzewalska, M.; Literák, I.; Čapek, Miroslav; Sychra, O.; Calderón, V. Á.; Rodríguez, B. C.; Prudencio, C.; Martins, T. F.; Labruna, M. B.
Roč. 6, č. 4 (2015), s. 478-482 ISSN 1877-959X R&D Projects: GA AV ČR IAA601690901 Institutional support: RVO:68081766 Keywords : Rickettsia * Ticks * Birds * Ixodes * Amblyomma * Costa Rica Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.690, year: 2015
Yadav, Pragya D; Vincent, Martin J; Khristova, Marina; Kale, Charuta; Nichol, Stuart T; Mishra, Akhilesh C; Mourya, Devendra T
Nairobi sheep disease (NSD) virus, the prototype tick-borne virus of the genus Nairovirus, family Bunyaviridae is associated with acute hemorrhagic gastroenteritis in sheep and goats in East and Central Africa. The closely related Ganjam virus found in India is associated with febrile illness in humans and disease in livestock. The complete S, M and L segment sequences of Ganjam and NSD virus and partial sequence analysis of Ganjam viral RNA genome S, M and L segments encoding regions (396 bp, 701 bp and 425 bp) of the viral nucleocapsid (N), glycoprotein precursor (GPC) and L polymerase (L) proteins, respectively, was carried out for multiple Ganjam virus isolates obtained from 1954 to 2002 and from various regions of India. M segments of NSD and Ganjam virus encode a large ORF for the glycoprotein precursor (GPC), (1627 and 1624 amino acids in length, respectively) and their L segments encode a very large L polymerase (3991 amino acids). The complete S, M and L segments of NSD and Ganjam viruses were more closely related to one another than to other characterized nairoviruses, and no evidence of reassortment was found. However, the NSD and Ganjam virus complete M segment differed by 22.90% and 14.70%, for nucleotide and amino acid respectively, and the complete L segment nucleotide and protein differing by 9.90% and 2.70%, respectively among themselves. Ganjam and NSD virus, complete S segment differed by 9.40-10.40% and 3.2-4.10 for nucleotide and proteins while among Ganjam viruses 0.0-6.20% and 0.0-1.4%, variation was found for nucleotide and amino acids. Ganjam virus isolates differed by up to 17% and 11% at the nucleotide level for the partial S and L gene fragments, respectively, with less variation observed at the deduced amino acid level (10.5 and 2%, S and L, respectively). However, the virus partial M gene fragment (which encodes the hypervariable mucin-like domain) of these viruses differed by as much as 56% at the nucleotide level. Phylogenetic
Rivas, Juan J; Moreira-Soto, Andrés; Alvarado, Gilberth; Taylor, Lizeth; Calderón-Arguedas, Olger; Hun, Laya; Corrales-Aguilar, Eugenia; Morales, Juan Alberto; Troyo, Adriana
'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
Mărcuţan, Ioan-Daniel; Kalmár, Zsuzsa; Ionică, Angela Monica; D'Amico, Gianluca; Mihalca, Andrei Daniel; Vasile, Cozma; Sándor, Attila D
Birds are important hosts and dispersers of parasitic arthropods and vector-borne zoonotic pathogens. Particularly migratory species may carry these parasites over long distances in short time periods. Migratory hotspots present ideal conditions to get a snapshot of parasite and pathogen diversity of birds migrating between continents. The aim of this study was to investigate the presence and diversity of Rickettsia spp. in ticks collected from birds at a migratory hot-spot in the Danube Delta, Romania, eastern Europe. DNA was extracted from ticks that were collected from migratory birds in the Danube Delta during migratory seasons in 2011-2012. Two 360 bp fragments of the 16S ribosomal RNA gene and a 381 bp fragment Gene gltA were PCR amplified and analyzed by sequence analysis (performed at Macrogen Europe, Amsterdam, The Netherlands). Nucleotide sequences were compared to reference sequences available in the GenBank database, using Basic Local Alignment Search Tool. Four hundred ticks of four different species were found on 11 bird species. The prevalence of Rickettsia spp. infection was 14 % (56/400, CI: 11.7-29.1), with significantly more nymphs hosting rickettsial infection compared to larvae (48 vs 7; P birds migrating through eastern Europe may carry ticks infected with a high diversity of rickettsial pathogens, with four Rickettsia spp. recorded. Migratory direction was important for pathogen burden, with seasonal differences in the occurrence of individual Rickettsia species. Here we report the first individual records of different Rickettsia spp. in H. concinna (R. monacensis), I. arboricola (R. helvetica, R. massiliae) and I. redikorzevi (R. helvetica) and also the first geographical record of occurrence of R. massiliae in Romania, representing the easternmost observation on the continent.
Ogrzewalska, Maria; Literák, Ivan; Capek, Miroslav; Sychra, Oldřich; Calderón, Víctor Álvarez; Rodríguez, Bernardo Calvo; Prudencio, Carlos; Martins, Thiago F; Labruna, Marcelo B
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. Copyright © 2015 Elsevier GmbH. All rights reserved.
Cicuttin, Gabriel L; De Salvo, María N; La Rosa, Isabel; Dohmen, Federico E Gury
Bats are potential reservoirs of many vector-borne bacterial pathogens. The aim of the present study was to detect species of Anaplasma, Ehrlichia, Neorickettsia, Rickettsia, Borrelia and Bartonella in Brazilian free-tailed bats (Tadarida brasiliensis, Molossidae) from Buenos Aires city, Argentina. Between 2012 and 2013, 61 T. brasiliensis from urban areas of Buenos Aires city were studied. The samples were molecularly screened by PCR and sequencing. Five bats (8.2%) were positive to Neorickettsia risticii, one (1.6%) was positive to Rickettsia sp. and three bats (4.9%) to Bartonella sp. For molecular characterization, the positive samples were subjected to amplification and sequencing of a fragment of p51 gene for N. risticii, a fragment of citrate synthase gene (gltA) for Rickettsia genus and a fragment of gltA for Bartonella genus. Phylogenetic tree was constructed using the maximum-likelihood method. Phylogenetic analysis of N. risticii detect in our study revealed that it relates to findings in the USA West Coast; Rickettsia sp. detected is phylogenetically within R. bellii group, which also includes many other Rickettsia endosymbionts of insects; and Bartonella sp. found is related to various Bartonella spp. described in Vespertilionidae bats, which are phylogenetically related to Molossidae. Our results are in accordance to previous findings, which demonstrate that insectivorous bats could be infected with vector-borne bacteria representing a potential risk to public health. Future research is necessary to clarify the circulation of these pathogens in bats from Buenos Aires. Copyright © 2017 Elsevier Ltd. All rights reserved.
Zhao, Shan-Shan; Li, Hong-Yu; Yin, Xiao-Ping; Liu, Zhi-Qiang; Chen, Chuang-Fu; Wang, Yuan-Zhi
Vermipsylla is a genus of the family Vermipsyllidae within the order Siphonaptera of fleas. Vermipsylla alakurt is mainly distributed in alpine pastoral areas of Kazakhstan, Mongolia, China and Nepal, and infests sheep, yaks and horses, causing irritation, poor condition, anaemia and even death. However, to date, no rickettsial agents have been reported in V. alakurt. A total of 133 fleas were collected directly from the tails of three sheep flocks (n = 335) in Minfeng County, Xinjiang Uygur Autonomous Region, north-western China. Of these, 55 fleas were identified by morphological examination and molecular analysis of four loci (the ribosomal 18S and 28S rDNA genes and the mitochondrial genes cytochrome c oxidase subunit II and elongation factor 1-alpha). Eight Rickettsia-specific gene fragments originated from seven genes: the 17-kilodalton antigen gene (17-kDa), citrate synthase gene (gltA), 16S rRNA gene (rrs), outer membrane protein A gene (ompA), surface cell antigen 1 gene (sca1), PS120 protein gene (gene D), and outer membrane protein B gene (ompB, two fragments), were used to identify the species of Rickettsia in 53 fleas. The amplified products were sequenced and included in a phylogenetic analysis to verify the taxonomic identification of the rickettsial agents. Based on morphological and molecular evidence, the flea was identified as Vermipsylla alakurt. Nine samples were positive (16.98 %, 9/53) for Rickettsia spp. The phylogenetic tree revealed that the rickettsial agents found in V. alakurt cluster with Candidatus Rickettsia barbariae. Our study suggests that: (i) V. alakurt may serve as a carrier for Candidatus R. barbariae; and (ii) Candidatus R. barbariae, previously reported in Israel, is the eighth newly discovered validated Rickettsia species in China. This finding extends our knowledge of the distribution of Candidatus R. barbariae and the profile of carriers, which not only comprise ticks but also fleas.
Kamani, Joshua; Baneth, Gad; Gutiérrez, Ricardo; Nachum-Biala, Yaarit; Mumcuoglu, Kosta Y; Harrus, Shimon
Rodents are hosts of numerous pathogenic agents of public health importance globally. Their ability to harbor these pathogens without showing overt clinical signs of disease has epidemiologic consequences. In some rural settings in Nigeria, humans and rodents do not only share feeds and abode, but the latter may end up on the table of the former as a source of protein, thereby increasing the risks of disease transmission. Molecular assays were used to detect and characterize two agents of zoonotic importance, Coxiella burnetii and Rickettsia spp. in 194 peridomestic rodents captured in a peri-urban setting in Nigeria, and 32 pools of ectoparasites removed from them, to determine their possible role in the epidemiology of these diseases in this country. Targeting and characterizing the insertion sequence IS1111, C. burnetii DNA was detected in 4 out of 194 (2.1%) rodents comprising 3 out of 121 (2.5%) Rattus norvegicus and 1 out of 48 (2.1%) Rattus rattus screened in this study. Rickettsia spp. DNA was detected in two Rhipicephalus sanginueus sensu lato pools (i.e. RT1 and RT4) using the citrate synthase (gltA) gene and further characterized by amplification and sequence analysis of six genes to determine their identity. The RT1 sample consistently gave 98-100% identity to Rickettsia conorii str. Malish 7 for the various genes and loci studied. However, the identity of RT4 could not be definitively determined due to variable identities to different Rickettsia spp. according to the gene or loci under consideration. Further isolation study to determine if the RT4 characterized is a new variant or a mixture of sequences of different rickettsiae within the pool will be worthwhile. Copyright © 2017 Elsevier GmbH. All rights reserved.
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
Richard Campos Pacheco
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.
Walker, David H; Olano, Juan P
...) library and challenge with R. prowazekii, R. rickettsii, and 0. tsutsugamushi; 2) To determine the role of NF-KB, cytokines, ROS and NO in intracellular killing of rickettsia-infected monolayers containing adapteins and 3...
Shaw, Chris D.
This paper introduces an analysis-based zoomable visualization technique for displaying the location of genes across many related species of microbes. The purpose of this visualizatiuon is to enable a biologist to examine the layout of genes in the organism of interest with respect to the gene organization of related organisms. During the genomic annotation process, the ability to observe gene organization in common with previously annotated genomes can help a biologist better confirm the structure and function of newly analyzed microbe DNA sequences. We have developed a visualization and analysis tool that enables the biologist to observe and examine gene organization among genomes, in the context of the primary sequence of interest. This paper describes the visualization and analysis steps, and presents a case study using a number of Rickettsia genomes.
Noh, Yoontae; Lee, Yeong Seon; Kim, Heung-Chul; Chong, Sung-Tae; Klein, Terry A; Jiang, Ju; Richards, Allen L; Lee, Hae Kyeong; Kim, Su Yeon
Rickettsiae constitute a group of arthropod-borne, Gram-negative, obligate intracellular bacteria that are the causative agents of diseases ranging from mild to life threatening that impact on medical and veterinary health worldwide. A total of 6,484 ticks were collected by tick drag from June-October 2013 in the southwestern provinces of the Republic of Korea (ROK) (Jeollanam, n = 3,995; Jeollabuk, n = 680; Chungcheongnam, n = 1,478; and Chungcheongbuk, n = 331). Ticks were sorted into 311 pools according to species, collection site, and stage of development. DNA preparations of tick pools were assayed for rickettsiae by 17 kDa antigen gene and ompA nested PCR (nPCR) assays and the resulting amplicons sequenced to determine the identity and prevalence of spotted fever group rickettsiae (SFGR). Haemaphysalis longicornis (4,471; 52 adults, 123 nymphs and 4,296 larvae) were the most commonly collected ticks, followed by Haemaphysalis flava (1,582; 28 adults, 263 nymphs and 1,291 larvae), and Ixodes nipponensis (431; 25 adults, 5 nymphs and 401 larvae). The minimum field infection rate/100 ticks (assuming 1 positive tick/pool) was 0.93% for the 17 kDa antigen gene and 0.82% for the ompA nPCR assays. The partial 17 kDa antigen and ompA gene sequences from positive pools of H. longicornis were similar to: Rickettsia sp. HI550 (99.4-100%), Rickettsia sp. FUJ98 (99.3-100%), Rickettsia sp. HIR/D91 (99.3-100%), and R. japonica (99.7%). One sequence of the partial 17 kDa antigen gene for H. flava was similar to Rickettsia sp. 17kd-005 (99.7%), while seven sequences of the 17 kDa antigen gene obtained from I. nipponensis ticks were similar to R. monacensis IrR/Munich (98.7-100%) and Rickettsia sp. IRS3 (98.9%). SFG rickettsiae were detected in three species of ixodid ticks collected in the southwestern provinces of the ROK during 2013. A number of rickettsiae have been recently reported from ticks in Korea, some of which were identified as medically
Aguirre, A A R; Garcia, Marcos Valério; Costa, Ivaneide Nunes da; Csordas, Bárbara Guimarães; Rodrigues, Vinícius da Silva; Medeiros, Jansen Fernandes; Andreotti, Renato
Human rickettsiosis has been recorded in the Amazon Biome. However, the epidemiological cycle of causative rickettsiae has not been fully accounted for in the Amazon region. This study investigates the presence of spotted fever group (SFG) Rickettsia spp. in free-living unfed ticks of the Amblyomma genus. The study was conducted in seven municipalities in Rondonia State, Brazil, where the main biomes are Amazon forest, Brazilian Savannah and their ecotones (areas of ecological tension between open ombrophilous forest and savannah). The following tick species were collected: Amblyomma cajennense (sensu lato) s.l., A. cajennense (sensu stricto) s.s., A. coelebs, A. naponense, A. oblongoguttatum, A. romitii, A. scalpturatum and A. sculptum. A total of 167 adults, 248 nymphs and 1004 larvae were subjected to DNA extraction and polymerase chain reaction (PCR) to determine the presence of SFG Rickettsia spp. PCR-positive samples included: one A. cajennense s.s. female and one A. cajennense s.l. male from a rural area in Vilhena Municipality; 10 nymphs and a sample of larvae of A. cajennense s.l. from a peri-urban area in Cacoal Municipality; and an A. oblongoguttatum adult male from a rural area of Pimenta Bueno Municipality. All sequences obtained exhibited 100% identity with Rickettsia amblyommatis sequences. This is the first confirmation of SFG Rickettsia in an A. oblongoguttatum tick. Furthermore, this is the first record of SFG Rickettsia in the municipalities targeted by this study. These results warn that SFG Rickettsia circulation poses a threat in Rondonia State (among Amazon-Savannah ecotones), and that this threat is increased by the fact that SFG Rickettsia infect a human-biting tick species hitherto unconfirmed as a vector. Copyright © 2018 Elsevier GmbH. All rights reserved.
Koetsveld, Joris; Tijsse-Klasen, Ellen; Herremans, Tineke; Hovius, Joppe W R; Sprong, Hein
Only a few reported cases indicate that Rickettsia helvetica and Rickettsia monacensis can cause disease in humans. Exposure to these two spotted fever group (SFG) rickettsiae occurs through bites of Ixodes ricinus, also the primary vector of Lyme borreliosis in Europe. To date, it is unclear how often exposure to these two microorganisms results in infection or disease. We show that of all the Borrelia burgdorferi s.l.-positive ticks, 25% were co-infected with rickettsiae. Predominantly R. helvetica was detected while R. monacensis was only found in approximately 2% of the ticks. In addition, exposure to tick-borne pathogens was compared by serology in healthy blood donors, erythema migrans (EM)-patients, and patients suspected of Lyme neuroborreliosis (LNB). As could be expected, seroreactivity against B. burgdorferi sensu lato was lower in blood donors (6%) compared to EM patients (34%) and suspected LNB cases (64%). Interestingly, seroreactivity against SFG Rickettsia antigens was not detected in serum samples from blood donors (0%), but 6% of the EM patients and 21% of the LNB suspects showed anti-rickettsial antibodies. Finally, the presence of B. burgdorferi s.l. and Rickettsia spp. in cerebrospinal fluid samples of a large cohort of patients suspected of LNB (n=208) was investigated by PCR. DNA of B. burgdorferi s.l., R. helvetica and R. monacensis was detected in seventeen, four and one patient, respectively. In conclusion, our data show that B. burgdorferi s.l. and SFG rickettsiae co-infection occurs in Dutch I. ricinus and that Lyme borreliosis patients, or patients suspected of Lyme borreliosis, are indeed exposed to both tick-borne pathogens. Whether SFG rickettsiae actually cause disease, and whether co-infections alter the clinical course of Lyme borreliosis, is not clear from our data, and warrants further investigation. Copyright © 2015 Elsevier GmbH. All rights reserved.
Barradas, Patrícia F; Vilhena, Hugo; Oliveira, Ana Cristina; Granada, Sara; Amorim, Irina; Ferreira, Paula; Cardoso, Luís; Gärtner, Fátima; de Sousa, Rita
Infections with tick-borne rickettsiae can cause diseases well known in humans but still not so well characterized in dogs. Susceptibility to infection depends on the virulence of Rickettsia spp. and only a few of them have been described to cause disease in dogs. The aim of this study was to investigate the exposure to Rickettsia spp. among a group of pet dogs from Luanda, Angola. Out of 103 dogs included in the study, 62 (60.2%) were infested with ticks. Plasma specimens tested for serology by an immunofluorescence assay (IFA) revealed that six (5.8%) dogs had detectable immunoglobulin G (IgG) antibodies to spotted fever group Rickettsia (SFGR), with endpoint titers of 64 for two dogs, 128 for three dogs and 1024 for one dog. From the seropositive group of dogs, five (83%) of them were males, with their age ranging from 1 to 8 years old. Among the seropositive dogs, four (66.7%) were parasitized with ticks and no breed (or cross) was found to be associated with specific antibodies. Rickettsia spp. DNA was detected by nested-polymerase chain reaction (PCR) in two (1.9%) dogs that were found to be seronegative. Seroprevalence and molecular detection of Rickettsia spp. infection in this group of pet dogs from Luanda is low compared with other studies performed in the same type of hosts in other areas. Although many dogs were parasitized with ticks, a low prevalence of Rickettsia spp. could be related with the hypothesis of a low rickettsial prevalence in the infesting ticks. This study provides evidence that dogs in Luanda are exposed to Rickettsia spp., but further studies are needed to better characterize the bacterial infections in dogs and in their ectoparasites.
Peniche-Lara, Gaspar; Dzul-Rosado, Karla; Pérez-Osorio, Carlos; Zavala-Castro, Jorge
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.
Full Text Available El objetivo del estudio fue detectar especies del género Rickettsia en garrapatas de la especie Amblyomma tigrinum colectadas sobre carnívoros domésticos y en sangre de caninos domésticos de la provincia de San Luis (Argentina. Entre 2013 y 2015 se colectaron 56 garrapatas adultas de la especie A. tigrinum sobre caninos y felinos domésticos, y se obtuvieron 65 muestras sanguíneas de caninos. Tres garrapatas resultaron positivas mediante la amplificación de un fragmento del espacio intergénico 23S-5S ARNr del género Rickettsia, lográndose secuenciar uno de los productos positivos. La muestra positiva secuenciada también resultó positiva por PCRs de los fragmentos de los genes gltA y ompA. Las secuencias obtenidas resultaron tener una identidad del 100 % de identidad con “Candidatus Rickettsia andeanae”. Todas las muestras sanguíneas resultaron negativas. “Ca. R. andeanae” no ha sido asociada con enfermedad en humanos o animales, sin embargo, es necesario realizar nuevas investigaciones para lograr un mayor conocimiento del riesgo potencial de transmisión de rickettsiosis en la región. SUMMARY. “Candidatus Rickettsia andeanae” in Amblyomma tigrinum ticks from San Luis (Argentina. The aim of this study was to detect species of Rickettsia in Amblyomma tigrinum ticks collected from domestic carnivores and blood of domestic dogs of San Luis (Argentina. Between 2013 and 2015, 56 adults of A. tigrinum from dogs and cats and 65 blood from dogs were collected. Three ticks were positive by amplification of a 23S-5S rRNA fragment, and the sequence of one of the positive products was obtained. The positive sample sequenced was positive by PCRs of fragments of genes gltA and ompA. The sequences obtained were 100% identical with "Candidatus Rickettsia andeanae". All blood samples were negative. “Ca. R. andeanae” has not been associated with disease in humans or animals; however, further research is necessary to achieve greater
Crawford, Jacob E; Alves, Joel M; Palmer, William J; Day, Jonathan P; Sylla, Massamba; Ramasamy, Ranjan; Surendran, Sinnathamby N; Black, William C; Pain, Arnab; Jiggins, Francis M
The mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans. To understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants. We conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for disease transmission.
Crawford, Jacob E.
BackgroundThe mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans.ResultsTo understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants.ConclusionsWe conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for
Movila, Alexandru; Reye, Anna L; Dubinina, Helen V; Tolstenkov, Oleg O; Toderas, Ion; Hübschen, Judith M; Muller, Claude P; Alekseev, Andrey N
To reveal the prevalence of spotted fever group (SFG) rickettsiae and Babesia sp. in Ixodes ricinus (L.) ticks from migratory birds, 236 specimens represented 8 species of Passeriformes and were collected at Curonian Spit in Kaliningrad enclave of North-Western Russia. The ticks (total 126) being detached from four bird species, Turdus philomelos, Fringilla coelebs, Parus major, and Sturnus vulgaris, were investigated by PCR using the primers Rp CS.877p/Rp CS.1258n for the detection of Rickettsia and BJ1/BN2 for Babesia spp. Babesia spp. were detected in 2 of 126 (1.6%) ticks. The partial sequence of 18S rDNA had 100% similarity to human pathogenic Babesia sp. EU1. The SFG rickettsiae were detected in 19 of 126 (15.1%) ticks collected from the above-mentioned bird species. BLAST analysis of SFG rickettsia gltA assigned sequences to human pathogenic Rickettsia helvetica (10.3%), Rickettsia monacensis (3.9%), and Rickettsia japonica (0.8%) with 98%-100% sequence similarity. The SFG rickettsiae and Babesia sp. EU1 in ticks collected from the passerines in Russia were detected for the first time. The survey indicates that migratory birds may become a reservoir for Babesia spp. and SFG rickettsiae. Future investigations need to characterize the role of birds in the epidemiology of these human pathogens in the region.
Paddock, Christopher D; Allerdice, Michelle E J; Karpathy, Sandor E; Nicholson, William L; Levin, Michael L; Smith, Travis C; Becker, Tom; Delph, Robert J; Knight, Robert N; Ritter, Jana M; Sanders, Jeanine H; Goddard, Jerome
In 1953, investigators at the Rocky Mountain Laboratories in Hamilton, MT, described the isolation of a spotted fever group Rickettsia (SFGR) species from Dermacentor parumapertus ticks collected from black-tailed jackrabbits ( Lepus californicus ) in northern Nevada. Several decades later, investigators characterized this SFGR (designated the parumapertus agent) by using mouse serotyping methods and determined that it represented a distinct rickettsial serotype closely related to Rickettsia parkeri ; nonetheless, the parumapertus agent was not further characterized or studied. To our knowledge, no isolates of the parumapertus agent remain in any rickettsial culture collection, which precludes contemporary phylogenetic placement of this enigmatic SFGR. To rediscover the parumapertus agent, adult-stage D. parumapertus ticks were collected from black-tailed jackrabbits shot or encountered as roadkills in Arizona, Utah, or Texas from 2011 to 2016. A total of 339 ticks were collected and evaluated for infection with Rickettsia species. Of 112 D. parumapertus ticks collected in south Texas, 16 (14.3%) contained partial ompA sequences with the closest identity (99.6%) to Rickettsia sp. strain Atlantic rainforest Aa46, an SFGR that is closely related or identical to an SFGR species that causes a mild rickettsiosis in several states of Brazil. A pure isolate, designated strain Black Gap, was cultivated in Vero E6 cells, and sequence analysis of the rrs , gltA , sca0 , sca5 , and sca4 genes also revealed the closest genetic identity to Rickettsia sp. Atlantic rainforest Aa46. Phylogenetic analysis of the five concatenated rickettsial genes place Rickettsia sp. strain Black Gap and Rickettsia sp. Atlantic rainforest Aa46 with R. parkeri in a distinct and well-supported clade. IMPORTANCE We suggest that Rickettsia sp. Black Gap and Rickettsia sp. Atlantic rainforest Aa46 represent nearly identical strains of R. parkeri and that Rickettsia sp. Black Gap or a very similar
Full Text Available Ticks were obtained from dogs from February to September of 1999 at weekly intervals, in the County of Piraí, State of Rio de Janeiro. Four hundred seventy four ixodids were taxonomically identified, 103 Amblyomma cajennense, seven Amblyomma ovale, 209 Rhipicephalus sanguineus, and 155 Amblyomma sp. An hemolymph test associated with Giemsa's stain revealed two specimens in 163 ticks tested (R. sanguineus and Amblyomma sp, containing rickettsia-like organisms. Direct immunofluorescence verified the presence of spotted fever group rickettsia in one specimen of R. sanguineus. Considering the limited information on rickettsiosis in Brazil, principally in relation to the vectors involved in perpetuating it in foci, these preliminary results give us an idea on the importance of infection in ticks, allowing to expand our knowledge on this zoonosis.
Brustolin, Joice Magali; da Silva Krawczak, Felipe; Alves, Marta Elena Machado; Weiller, Maria Amélia; de Souza, Camila Lopes; Rosa, Fábio Brum; Cadore, Gustavo Cauduro; Dos Anjos Lopes, Sônia Terezinha; Labruna, Marcelo Bahia; Vogel, Fernanda Silveira Flores; de Avila Botton, Sônia; Sangioni, Luís Antônio
This study describes experimental infection of guinea pigs (Cavia porcellus) infested with naturally infected Amblyomma ovale nymphs with Rickettsia sp. (Atlantic rainforest strain), and the capacity of A. ovale nymphs to transmit this bacterium. Twenty-six guinea pigs were divided into the following groups: G1, 10 animals infested with uninfected A. ovale nymphs; G2, 10 animals infested with nymphs infected with Rickettsia sp. (Atlantic rainforest strain); and G3, 6 animals without tick infestation. Blood samples were taken 7, 14, 21, and 28 days post-infestation for serological and hematological tests. For histopathological analysis and rickettsial DNA detection, fragments of the spleen, lung, brain, and liver were harvested after euthanasia. The average feeding period for nymphs was 6.6 days for G1 and 6 days for G2. Hemolymph and PCR assays, performed to detect the causative agent in ticks, indicated that in G1, all ticks were negative, and in G2, all nymphs were positive by PCR and 80% (8/10) was positive by hemolymph tests. The only clinical change was skin scarring at the tick attachment site. Hematological parameters indicated leukopenia and total plasma protein (TPP) increased with decreased platelets in G1. In G2, leukocytosis, neutrophilia, monocytosis, an increase in platelets, and reduced TPP were observed. Only G2 guinea pigs were seroconverted (80%; 8/10). Histopathology tests indicated mild, diffuse hemosiderosis and mild, multifocal, follicular hyperplasia in the spleen. Molecular analysis did not detect Rickettsia sp. DNA in C. porcellus tissues. We demonstrated the capacity of A. ovale nymphs to transmit Rickettsia sp. (Atlantic rainforest strain) to guinea pigs.
Full Text Available Murine typhus is a rickettsiosis caused by Rickettsia typhi, whose transmission is carried out by rat fleas in urban settlements as classically known, but it also has been related to cat fleas in a sub-urban alternative cycle that has been suggested by recent reports. These studies remarks that in addition to rats, other animals like cats, opossums and dogs could be implied in the transmission of Rickettsia typhi as infected fleas obtained from serologically positive animals have been detected in samples from endemic areas. In Mexico, the higher number of murine typhus cases have been detected in the Yucatan peninsula, which includes a great southeastern region of Mexico that shows ecologic characteristics similar to the sub-urban alternative cycle recently described in Texas and California at the United States. To find out which are the particular ecologic characteristics of murine typhus transmission in this region, we analyzed blood and Rhipicephalus sanguineus ticks obtained from domestic dogs by molecular approaches, demonstrating that both samples were infected by Rickettsia typhi. Following this, we obtained isolates that were analyzed by genetic sequencing to corroborate this infection in 100% of the analyzed samples. This evidence suggests for the first time that ticks and dogs could be actively participating in the transmission of murine typhus, in a role that requires further studies for its precise description.
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.
Crawford, Jacob E.; Alves, Joel M.; Palmer, William J.; Day, Jonathan P.; Sylla, Massamba; Ramasamy, Ranjan; Surendran, Sinnathamby N.; Black, William C., IV; Pain, Arnab; Jiggins, Francis M.
this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri
Seroprevalencia de Leptospira sp., Rickettsia sp. Ehrlichia sp. en trabajadores rurales del departamento de Sucre, Colombia Seroprevalence of Leptospira sp., Rickettsia sp. and Ehrlichia sp. in rural workers of Sucre, Colombia
Full Text Available Objective. Determinar la seroprevalencia de Leptospira sp., Rickettsia sp. y Ehrlichia sp. en trabajadores de áreas rurales del departamento de Sucre. Material y métodos. Se realizó un estudio escriptivo, prospectivo, de corte transversal, que pretendió determinar la seroprevalencia e Leptospira sp., Rickettsia sp. y Ehrlichia sp. en 90 trabajadores de áreas rurales del departamento de Sucre. Se estableció la presencia de anticuerpos séricos anti-IgM específicos anti-Leptospira por la técnica de ELISA indirecta. Para la determinación de Rickettsia sp. y Ehrlichia sp. se uso la técnica de inmunofluorescencia indirecta. Resultados. La población evaluada estaba compuesta por 27 (30% ordeñadores, 21 (23% jornaleros, 18 (20% profesionales del campo y 24 (27% que realizaban otras actividades. Ventidós (24% muestras resultaron positivas en alguna de las pruebas. De éstas, 12 (13,3% fueron positivas para Leptospira sp., 7 (7,8% para Rickettsia sp. y 3 (3,3% ara Ehrlichia sp. Conclusión. Este fue el primer estudio que se llevó a cabo en el departamento de Sucre y permitió demostrar que existe una prevalencia importante de Leptospira p.,Rickettsia sp. y Ehrlichia sp.. Los factores de riesgo ocupacional fueron factores determinantes en la seropositividad.Objective. To determine the seroprevalence of Leptospira sp., Rickettsia sp. and Ehrlichia sp. in agricultural workers of Sucre. Methods. A descriptive prospective cross-sectional study was conducted in ninety rural workers of Sucre. Presence of serum antibodies anti-IgM specific anti-Leptospira by indirect ELISA was established. For the determination of Rickettsia and Ehrlichia indirect inmunoflorescence was used. Results.The population was composed by 27 (30% milkers, 21 (23% day workers, 18 farm professionals (20% and 24 (26% workers in others activities. A total of 22 (24% samples were positive to some test. Twelve (13.3% were positive to Leptospira sp., seven (7.8% to Rickettsia sp
Kliot, Adi; Cilia, Michelle; Czosnek, Henryk
ABSTRACT Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. IMPORTANCE Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with
Balayeva, N M; Demkin, V V; Rydkina, E B; Ignatovich, V F; Artemiev, M I; Lichoded LYa; Genig, V A
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.
Gualtieri, Liberata; Nugnes, Francesco; Nappo, Anna G; Gebiola, Marco; Bernardo, Umberto
The incidence of horizontal transmission as a route for spreading symbiont infections is still being debated, but a common view is that horizontal transfers require intimate between-species relationships. Here we study a system that meets ideal requirements for horizontal transmission: the gall wasp Leptocybe invasa and its parasitoid Quadrastichus mendeli (Hymenoptera: Eulophidae). These wasps belong to the same subfamily, spend most of their lives inside the same minute gall and are both infected by Rickettsia, a maternally inherited endosymbiotic bacteria that infects several arthropods, sometimes manipulating their reproduction, like inducing thelytokous parthenogenesis in L. invasa. Despite intimate contact, close phylogenetic relationship and the parasitoid's host specificity, we show that host and parasitoid do not share the same Rickettsia. We provide indirect evidence that Rickettsia infecting Q. mendeli may be inducing thelytokous parthenogenesis, as the symbiont is densely present in the reproductive apparatus and is vertically transmitted. Phylogenetic analyses based on 16S and gltA placed this symbiont in the leech group. The confirmed and presumed parthenogenesis-inducing Rickettsia discovered so far only infect eulophid wasps, and belong to three different groups, suggesting multiple independent evolution of the parthenogenesis inducing phenotype. We also show some degree of cospeciation between Rickettsia and their eulophid hosts. © FEMS 2017. All rights reserved. For permissions, please e-mail: email@example.com.
Africa Insight is a quarterly, peer-reviewed journal of the Africa Institute of South Africa. It is accredited by the South African National Department of Higher Education and Training (DHET) and is indexed in the International Bibliography of Social Science (IBSS). It is a multi-disciplinary journal primarily focusing on African ...
Caspi-Fluger, Ayelet; Inbar, Moshe; Mozes-Daube, Netta; Mouton, Laurence; Hunter, Martha S.; Zchori-Fein, Einat
Intracellular symbionts of arthropods have diverse influences on their hosts, and their functions generally appear to be associated with their localization within the host. The effect of localization pattern on the role of a particular symbiont cannot normally be tested since the localization pattern within hosts is generally invariant. However, in Israel, the secondary symbiont Rickettsia is unusual in that it presents two distinct localization patterns throughout development and adulthood in its whitefly host, Bemisia tabaci (B biotype). In the “scattered” pattern, Rickettsia is localized throughout the whitefly hemocoel, excluding the bacteriocytes, where the obligate symbiont Portiera aleyrodidarum and some other secondary symbionts are housed. In the “confined” pattern, Rickettsia is restricted to the bacteriocytes. We examined the effects of these patterns on Rickettsia densities, association with other symbionts (Portiera and Hamiltonella defensa inside the bacteriocytes) and on the potential for horizontal transmission to the parasitoid wasp, Eretmocerus mundus, while the wasp larvae are developing within the whitefly nymph. Sequences of four Rickettsia genes were found to be identical for both localization patterns, suggesting that they are closely related strains. However, real-time PCR analysis showed very different dynamics for the two localization types. On the first day post-adult emergence, Rickettsia densities were 21 times higher in the “confined” pattern vs. “scattered” pattern whiteflies. During adulthood, Rickettsia increased in density in the “scattered” pattern whiteflies until it reached the “confined” pattern Rickettsia density on day 21. No correlation between Rickettsia densities and Hamiltonella or Portiera densities were found for either localization pattern. Using FISH technique, we found Rickettsia in the gut of the parasitoid wasps only when they developed on whiteflies with the “scattered” pattern. The
Richey, Lisa Ann; Ponte, Stefano
a. Lisa Ann Richey, Roskilde University and Stefano Ponte, Danish Institute for International Studies - Brand Aid and Africa b. Fantu Cheru, Nordic Africa Institute - The Right to Consume: Compassion and the Intricate New Phase of Capitalism and Africa c. Rita Abrahamsen, University of Ottawa...... - Africa in a Global Political Economy of Symbolic Goods d. Graham Harrison, University of Sheffield - Images and Representations of Africa: Old, New and Beyond e. Claire Mercer, London School of Economics and Political Science - The Privatisation of Aid? f. Dan Brockington, University of Manchester...
Hornok, Sándor; de la Fuente, José; Biró, Nóra; Fernández de Mera, Isabel G; Meli, Marina L; Elek, Vilmos; Gönczi, Eniko; Meili, Theres; Tánczos, Balázs; Farkas, Róbert; Lutz, Hans; Hofmann-Lehmann, Regina
To evaluate the presence of rickettsial agents in hippoboscid flies with molecular methods, 81 sheep keds (Melophagus ovinus) were collected from 23 sheep, 144 deer keds (Lipoptena cervi) were caught in the environment, and a further 463 and 59 individuals of the latter species were obtained from fresh carcasses of 29 red deer and 17 roe deer, respectively. DNA was extracted individually or in pools. Anaplasma ovis was demonstrated in all examined sheep keds, and from one pool of free-living deer keds. Rickettsia helvetica or other, unidentified rickettsiae were also present in one pool of sheep keds, and in four pools of deer keds from both red deer and roe deer. This is the first account of polymerase chain reaction positivity of hippoboscid flies for A. ovis and rickettsiae. These results raise the possibility that-apart from cattle and roe deer as already reported-sheep and red deer might also play a reservoir role in the epidemiology of rickettsioses.
Conclusion: Baseline ETH molecular resistance before second-line treatment is a concern. Unfavorable treatment outcomes of patients with ethA, ethR, and inhA mutations highlight the importance of genotypic testing before initiation of treatment containing ETH. The clinical significance of whole genome analysis for early detection of mutations predictive of treatment failure needs further investigation.
Meinel, D M; Kuehl, R; Zbinden, R; Boskova, V; Garzoni, C; Fadini, D; Dolina, M; Blümel, B; Weibel, T; Tschudin-Sutter, S; Widmer, A F; Bielicki, J A; Dierig, A; Heininger, U; Konrad, R; Berger, A; Hinic, V; Goldenberger, D; Blaich, A; Stadler, T; Battegay, M; Sing, A; Egli, A
Toxigenic Corynebacterium diphtheriae is an important and potentially fatal threat to patients and public health. During the current dramatic influx of refugees into Europe, our objective was to use whole genome sequencing for the characterization of a suspected outbreak of C. diphtheriae wound infections among refugees. After conventional culture, we identified C. diphtheriae using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and investigated toxigenicity by PCR. Whole genome sequencing was performed on a MiSeq Illumina with >70×coverage, 2×250 bp read length, and mapping against a reference genome. Twenty cases of cutaneous C. diphtheriae in refugees from East African countries and Syria identified between April and August 2015 were included. Patients presented with wound infections shortly after arrival in Switzerland and Germany. Toxin production was detected in 9/20 (45%) isolates. Whole genome sequencing-based typing revealed relatedness between isolates using neighbour-joining algorithms. We detected three separate clusters among epidemiologically related refugees. Although the isolates within a cluster showed strong relatedness, isolates differed by >50 nucleotide polymorphisms. Toxigenic C. diphtheriae associated wound infections are currently observed more frequently in Europe, due to refugees travelling under poor hygienic conditions. Close genetic relatedness of C. diphtheriae isolates from 20 refugees with wound infections indicates likely transmission between patients. However, the diversity within each cluster and phylogenetic time-tree analysis suggest that transmissions happened several months ago, most likely outside Europe. Whole genome sequencing offers the potential to describe outbreaks at very high resolution and is a helpful tool in infection tracking and identification of transmission routes. Copyright Â© 2016. Published by Elsevier Ltd.
Full Text Available Developing genomic selection (GS models is an important step in applying GS to accelerate the rate of genetic gain in grain yield in plant breeding. In this study, seven genomic prediction models under two cross-validation (CV scenarios were tested on 287 advanced elite spring wheat lines phenotyped for grain yield (GY, thousand-grain weight (GW, grain number (GN, and thermal time for flowering (TTF in 18 international environments (year-location combinations in major wheat-producing countries in 2010 and 2011. Prediction models with genomic and pedigree information included main effects and interaction with environments. Two random CV schemes were applied to predict a subset of lines that were not observed in any of the 18 environments (CV1, and a subset of lines that were not observed in a set of the environments, but were observed in other environments (CV2. Genomic prediction models, including genotype × environment (G×E interaction, had the highest average prediction ability under the CV1 scenario for GY (0.31, GN (0.32, GW (0.45, and TTF (0.27. For CV2, the average prediction ability of the model including the interaction terms was generally high for GY (0.38, GN (0.43, GW (0.63, and TTF (0.53. Wheat lines in site-year combinations in Mexico and India had relatively high prediction ability for GY and GW. Results indicated that prediction ability of lines not observed in certain environments could be relatively high for genomic selection when predicting G×E interaction in multi-environment trials.
Minichová, Lenka; Hamšíková, Zuzana; Mahríková, Lenka; Slovák, Mirko; Kocianová, Elena; Kazimírová, Mária; Škultéty, Ľudovít; Štefanidesová, Katarína; Špitalská, Eva
Natural foci of tick-borne spotted fever group (SFG) rickettsiae of public health concern have been found in Slovakia, but the role of rodents in their circulation is unclear. Ticks (Ixodes ricinus, Ixodes trianguliceps, Dermacentor marginatus, Dermacentor reticulatus, Haemaphysalis concinna and Haemaphysalis inermis) and tissues of rodents (Apodemus flavicollis, Apodemus sylvaticus, Myodes glareolus, Microtus arvalis, Microtus subterraneus and Micromys minutus) were examined for the presence of SFG rickettsiae and Coxiella burnetii by molecular methods. Suburban, natural and rural habitats were monitored to acquire information on the role of ticks and rodents in the agents' maintenance in various habitat types of Slovakia. The overall prevalence of rickettsial infection in questing I. ricinus and D. marginatus was 6.6% and 21.4%, respectively. Rickettsia helvetica, R. monacensis and non-identified rickettsial species were detected in I. ricinus, whereas R. slovaca and R. raoultii were identified in D. marginatus. Rickettsia spp.-infected I. ricinus occurred during the whole tick questing period. Rickettsia helvetica dominated (80.5%) followed by R. monacensis (6.5%). The species were present in all studied habitats. Rickettsia slovaca (66.7%) and R. raoultii (33.3%) were identified in D. marginatus from the rural habitat. Apodemus flavicollis was the most infested rodent species with I. ricinus, but My. glareolus carried the highest proportion of Rickettsia-positive I. ricinus larvae. Only 0.5% of rodents (A. flavicollis) and 5.2% of engorged I. ricinus removed from My. glareolus, A. flavicollis and M. arvalis were R. helvetica- and R. monacensis-positive. Coxiella burnetii was not detected in any of the tested samples. We hypothesize that rodents could play a role as carriers of infected ticks and contribute to the maintenance of rickettsial pathogens in natural foci. Long-term presence of SFG Rickettsia spp. was confirmed in questing ticks from different habitat
Full Text Available Rocky Mountain spotted fever is an acute illness caused by Rickettsia rickettsii (R. rickettsii and is transmitted by the bite of ticks of the genera Dermacentor, Amblyomma and Rhipicephalus. The illness results in a high mortality rate and may be easily confused with other febrile syndromes. In Yucatan State, Mexico, childhood cases with a high mortality have been reported. In this work we report the isolation of a Mexican R. rickettsii strain from a tick egg mass using an alternative method for Rickettsia isolation with 24-well plates. We also identified a potential vector of R. rickettsii in the southeast of Mexico, which is Amblyomma parvum.
Oaks, S.C.Jr.; Osterman, J.V.
The temperature range for optimum growth of Rickettsia conorii in suspension culture of gamma-irradiated L cells was 32 to 38 degC, resulting in rickettsial doubling times between 4.1 and 6.0 hrs. An asynchronous release of Rickettsia conorii from host cells was suggested by the constant increase in percent cells infected over a 36 hrs period. Rickettsial growth was optimal at neutral to slightly alkaline extracellular pH levels. A moderately acidic pH, however, resulted in an increase in doubling time from 4.1 to 7.8 hrs. (author)
Šlapeta, Jan; Lawrence, Andrea; Reichel, Michael P
Fleas are commonly recorded on stray as well as domestic dogs and cats in Hong Kong. Fleas can be a major cause of pruritus in dogs and cats and also vectors of potentially zoonotic bacteria in the genera Rickettsia and Bartonella. Morphological examination of 174 fleas from dogs and cats living in Hong Kong revealed only cat fleas (Ctenocephalides felis). Cytochrome c oxidase subunit 1 gene (cox1) genotyping of 20 randomly selected specimens, revealed three cox1 haplotypes (HK-h1 to HK-h3). The most common haplotype was HK-h1 with 17 specimens (17/20, 85%). HK-h1 was identical to cox1 sequences of fleas in Thailand and Fiji. HK-h1 and HK-h2 form a distinct cat flea cox1 clade previously recognized as the Clade 3. HK-h3 forms a new Clade 6. A multiplex Bartonella and Rickettsia real-time PCR of DNA from 20 C. felis found Bartonella and Rickettsia DNA in three (15%) and ten (50%) C. felis, respectively. DNA sequencing confirmed the presence of R. felis, B. clarridgeiae and Bartonella henselae. This is the first reported study of that kind in Hong Kong, and further work is required to expand the survey of companion animals in the geographical region. The sampling of fleas on domestic cats and dogs in Hong Kong revealed them to be exclusively infested by the cat flea and to be harbouring pathogens of zoonotic potential. Copyright © 2017 Elsevier B.V. All rights reserved.
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
Eliane M Piranda
Full Text Available The bacterium Rickettsia rickettsii is the etiological agent of an acute, severe disease called Rocky Mountain spotted fever in the United States or Brazilian spotted fever (BSF in Brazil. In addition to these two countries, the disease has also been reported to affect humans in Mexico, Costa Rica, Panama, Colombia and Argentina. Like humans, dogs are also susceptible to R. rickettsii infection. However, despite the wide distribution of R. rickettsii in the Western Hemisphere, reports of R. rickettsii-induced illness in dogs has been restricted to the United States. The present study evaluated the pathogenicity for dogs of a South American strain of R. rickettsii. Three groups of dogs were evaluated: group 1 (G1 was inoculated ip with R. rickettsii; group 2 (G2 was infested by R. rickettsii-infected ticks; and the control group (G3 was infested by uninfected ticks. During the study, no clinical abnormalities, Rickettsia DNA or R. rickettsii-reactive antibodies were detected in G3. In contrast, all G1 and G2 dogs developed signs of rickettsial infection, i.e., fever, lethargy, anorexia, ocular lesions, thrombocytopenia, anemia and detectable levels of Rickettsia DNA and R. rickettsii-reactive antibodies in their blood. Rickettsemia started 3-8 days after inoculation or tick infestation and lasted for 3-13 days. Our results indicate that a Brazilian strain of R. rickettsii is pathogenic for dogs, suggesting that canine clinical illness due to R. rickettsii has been unreported in Brazil and possibly in the other South American countries where BSF has been reported among humans.
Straily, Anne; Feldpausch, Amanda; Ulbrich, Carl; Schell, Kiersten; Casillas, Shannon; Zaki, Sherif R; Denison, Amy M; Condit, Marah; Gabel, Julie; Paddock, Christopher D
During 2012-2014, five cases of Rickettsia parkeri rickettsiosis were identified by a single urgent care practice in Georgia, located approximately 40 miles southwest of Atlanta. Symptom onset occurred during June-October, and all patients had a known tick bite. Patients ranged in age from 27 to 72 years (median = 53 years), and all were male. The most commonly reported initial signs were erythema (n = 3) and swelling (n = 2) at the site of the bite. Two patients reported fever and a third patient reported a rash and lymphadenopathy without fever. Other symptoms included myalgia (n = 3), chills (n = 3), fatigue (n = 2), arthralgia (n = 2), and headache (n = 2). Eschar biopsy specimens were collected from each patient using a 4-mm or 5-mm punch and placed in 10% neutral buffered formalin or sterile saline. These specimens were tested by immunohistochemical (IHC) stains, quantitative polymerase chain reaction (qPCR) assays, or cell culture isolation to determine if there was evidence of infection with a Rickettsia species (1). IHC evidence of spotted fever group rickettsiae was found in the eschar biopsy specimens in all five cases. In four cases, the biopsy specimens were also positive for R. parkeri by qPCR. The fifth case (specimen positive only by IHC testing) was considered a probable R. parkeri case based on clinical signs and symptoms. R. parkeri was grown in cell culture from one specimen from which isolation was attempted. All patients were treated with oral doxycycline (100 mg twice daily) for a minimum of 10 days, and all recovered.
Muul, I; Chai, K S
No focalization of rats (Rattus tiomanicus and R. argentiventer) infected with Rickettsia tsutsugamushi could be discerned over a 500 m trapping transect at the border between a forest and lalang grass (Imperata cylindrica). R. tiomanicus appeared to occupy 250 m of the transect on the average and had periods during which infections were observed which averaged 97 days. Calulations indicated that more than 50% of individuals become infected over their life-time. The high rate of infection in this and other areas described in earlier publications and the habits of the rats suggest that infected mites are densely and widely dispersed in the areas studied in Malaysia.
Alexsandra Rodrigues de Mendonça Favacho
Full Text Available Brazilian spotted fever (BSF is the most important and frequent rickettsial disease in Brazil. A fatal case of BSF is reported in a 32-year-old black man, who died of irreversible shock after five days of fever, severe headache and abdominal pain with no rash. Spleen, kidney and heart samples collected at autopsy were positive for Rickettsia rickettsii by PCR and sequencing. The authors emphasize the need for a high index of diagnostic suspicion for spotted fever in black patients. Absence of a skin rash should not dissuade clinicians from considering the possibility of BSF and initiating empirical therapy.
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.
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
boliviensis 3 (18.7) 1 (6.2) Ixodes pararicinus 2 (12.5) 0 Flea speciesb Adoratopsilla intermedia 2 (3.4) 0 Ctenocephalides felis 33 (55.9) 2 (3.4...analysis of a genus-common rickettsial antigen gene. J. Bacteriol. 171:5199–5201. 3. Azad, A. F., S. Radulovic, J. A. Higgins , B. H. Noden, and J. M...Y. Acad. Sci. 990:57–61. 21. Hackstadt, T. 1996. The biology of rickettsiae. Infect. Agents Dis. 5:127–143. 22. Higgins , J. A., S. Radulovic, M. E
Ndunguru, Joseph; Sseruwagi, Peter; Tairo, Fred; Stomeo, Francesca; Maina, Solomon; Djinkeng, Appolinaire; Kehoe, Monica; Boykin, Laura M.
Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) which are frequently found infecting cassava, one of sub-Saharan Africa’s most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production. PMID:26439260
Segura, Ferran; Pons, Immaculada; Sanfeliu, Isabel; Nogueras, María-Mercedes
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. Copyright © 2016 Elsevier GmbH. All rights reserved.
Rickettsia species infecting Amblyomma ticks from an area endemic for Brazilian spotted fever in Brazil Rickettsia infectando carrapatos Amblyomma de uma área endêmica para febre maculosa Brasileira no Brasil
Full Text Available This study reports rickettsial infection in Amblyomma cajennense and Amblyomma dubitatum ticks collected in an area of the state of Minas Gerais, Brazil, where Brazilian spotted fever is considered endemic. For this purpose, 400 adults of A. cajenennse and 200 adults of A. dubitatum, plus 2,000 larvae and 2,000 nymphs of Amblyomma spp. were collected from horses and from the vegetation. The ticks were tested for rickettsial infection through polymerase chain reaction (PCR protocols targeting portions of three rickettsial genes (gltA, ompA, and ompB. Only two free-living A. cajennense adult ticks, and four pools of free-living Amblyomma spp. nymphs were shown to contain rickettsial DNA. PCR products from the two A. cajennense adult ticks were shown to be identical to corresponding sequences of the Rickettsia rickettsii strain Sheila Smith. DNA sequences of gltA-PCR products of the four nymph pools of Amblyomma spp. revealed a new genotype, which was shown to be closest (99.4% to the corresponding sequence of Rickettsia tamurae. Our findings of two R. rickettsii-infected A. cajennense ticks corroborate the endemic status of the study area, where human cases of BSF were reported recently. In addition, we report for the first time a new Rickettsia genotype in Brazil.Este trabalho relata infecção por Rickettsia em carrapatos Amblyomma cajennense e Amblyomma dubitatum, colhidos numa área do Estado de Minas Gerais, onde a febre maculosa brasileira (FMB é considerada endêmica. Para esse estudo, 400 adultos de A. cajennense, 200 adultos de A. dubitatum, 2.000 larvas e 2.000 ninfas de Amblyomma spp. foram colhidas de equinos e da vegetação. Os carrapatos foram testados para infecção por rickettsia através de reação em cadeia pela polimerase (PCR direcionada a fragmentos de três genes de rickettsia (gltA, ompA, e ompB. Apenas 2 A. cajennense adultos de vida livre, e 4 grupos de ninfas de Amblyomma spp. continham DNA de rickettsia. Os produtos
Londoño, Andrés F; Acevedo-Gutiérrez, Leidy Y; Marín, Diana; Contreras, Verónica; Díaz, Francisco J; Valbuena, Gustavo; Labruna, Marcelo B; Hidalgo, Marylin; Arboleda, Margarita; Mattar, Salim; Solari, Sergio; Rodas, Juan D
In February 2006, an outbreak of human rickettsiosis occurred in the municipality of Necoclí Colombia, with 35% of lethality. This episode was, followed by two more, one in the municipality of Los Cordobas in 2007 with a 54% of lethality and the other one in the municipality of Turbo in 2008 with 27% of lethality. The aim of this study was to perform serological tests in healthy persons to determine the seroprevalence of antibodies against spotted fever group (SFG) rickettsiae and develop a survey to study some infection risk-related factors. A cross-sectional study was performed in 2011 and 2012. A blood sample and survey of associated factors was performed in healthy persons. A prevalence of 32%-41% was found in healthy people. From the multivariate analysis, we found that people living more than 16 years in these sites had a 79% higher risk of being seropositive and a 46% higher risk when they reported having birds in their houses if the variable of having a horse was included in the model. In conclusion, this study shows endemicity of at least one spotted fever group Rickettsia in the study zone. Copyright © 2017 Elsevier GmbH. All rights reserved.
Wood, Heidi; Dillon, Liz; Patel, Samir N; Ralevski, Filip
Relatively little is known about the prevalence of rickettsial species in Dermacentor ticks in eastern Canada. In this study, Dermacentor ticks from the province of Ontario, Canada, were tested for the presence of spotted fever group rickettsial (SFGR) species, Coxiella burnetii and Francisella tularensis. Rickettsia rickettsii was not detected in any ticks tested, but R. montanensis was detected at a prevalence of 2.2% in D. variabilis (17/778). Two other SFGR species, R. parkeri and Candidatus R. andeanae, were detected individually in 2 Amblyomma maculatum ticks. Rickettsia peacockii, a non-pathogenic endosymbiont, was detected in two D. andersonii ticks. Given the highly abundant nature of D. variabilis, surveillance for human pathogens in this species of tick has important public health implications, but the lack of detection of known human pathogens indicates a low risk of infection via this tick species in Ontario. However, the detection of R. parkeri in an adventive A. maculatum tick indicates that health care providers should be aware of the possibility of spotted fever rickettsioses in individuals with a history of travel outside of Ontario and symptoms compatible with a spotted fever rickettsiosis. Coxiella burnetii and Francisella tularensis, human pathogens also potentially transmitted by D. variabilis, were not detected in a subset of the ticks. Copyright © 2016 Elsevier GmbH. All rights reserved.
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.
Waite, R.T.; Shaw, E.I.; Winkler, H.H.; Wood, D.G.
The dnaA gene encoding the initiator protein of DNA replication was isolated from the obligate intracellular bacterium, Rickettsia prowazekii. Comparison of the deduced amino acid sequence of R. prowazekii DnaA with other bacterial DnaA proteins revealed extensive similarity. However, the rickettsial sequence is unique in the number of basic lysine residues found within a highly conserved portion of the putative DNA binding region, suggesting that the rickettsial protein may recognize a DNA sequence that differs from the consensus DnaA box sequence identified in other bacteria. Consensus DnaA box sequences, found upstream of many bacterial dnaA genes, were not identified upstream of rickettsial dnaA gene. In addition, gene organization within this region differed from that of other bacteria. The putative start of transcription of the rickettsial dnaA gene was localized to a site 522 nucleotides upstream of the DnaA start codon. Key words: Rickettsia prowazekii; dnaA gene; initiator protein (authors)
Diego A. Riveros-Pinilla
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.
Full Text Available Bacteria of the Rickettsia genus are agents of Brazilian Spotted Fever (BSF, a zoonotic disease which is difficult to diagnose, evolves quickly and can result in death. Antibodies against Rickettsia spp. in horses were studied, by means of Indirect Immunofluorescence Assay (IFAT ≥64, in 150 blood samples taken from animals in two Santa Catarina mesoregions (Planalto Serrano and Vale do Itajaí. The overall occurrence of Rickettsia spp. antibodies in horses was 18.66%, with cross-reactivity occurring in all positive samples for at least two of the species tested. Separately, according to the species, 25 (16.66% samples were positive for R. rickettsii, 15 (10% for R. parkeri, 22 (14.66% for R. amblyommii, 23 (15.33% for R. rhipicephali, 16 (10.66% for R. bellii and 19 (12.66% for R. felis. Only two animals resulted in a conclusive serodiagnosis, one for R. bellii and the other for R. rickettsii, at maximum dilutions of 1:4096 and 1:512, respectively. The occurrence of antibodies against Rickettsia spp. in horses from two mesoregions in the state of Santa Catarina indicates the movement of BSF agents in these sentinel animals and confirms the importance of studying spotted fever in the state of Santa Catarina.
Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. Here we report that infection with Rickettsia spp., a facultative endosymbiont of whiteflies...
W.-C. Cao (Wu-Chun); L. Zhan (Lin); S.J. de Vlas (Sake); B.-H. Wen (Bo-Hai); H. Yang (Honghui); J.H. Richardus (Jan Hendrik); J.D.F. Habbema (Dik)
textabstractIn total, 676 Dermacentor silvarum Olenev (Acari: Ixodidae) from a forest area of Jilin Province in northeastern China were examined by polymerase chain reaction for the presence of spotted fever group (SFG) Rickettsia. The overall positive rate was 10.7%, with a 95% confidence interval
Dubská, L.; Literák, I.; Kverek, P.; Roubalová, Eva; Kocianova, E.; Taragelova, V.
Roč. 3, č. 4 (2012), s. 265-268 ISSN 1877-959X Institutional support: RVO:60077344 Keywords : tick * Ixodes ricinus * Borrelia garinii * Anaplasma phagocytophilum * Rickettsia helvetica * Babesia sp. EU1 * Common nightingale Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.353, year: 2012 http://www.sciencedirect.com/science/article/pii/S1877959X12000556
von Fricken, Michael E; Lkhagvatseren, Sukhbaatar; Boldbaatar, Bazartseren; Nymadawa, Pagbajab; Weppelmann, Thomas A; Baigalmaa, Bekh-Ochir; Anderson, Benjamin D; Reller, Megan E; Lantos, Paul M; Gray, Gregory C
To better understand the epidemiology of tick-borne disease in Mongolia, a comprehensive seroprevalence study was conducted investigating exposure to Anaplasma spp. and spotted fever group (SFG) Rickettsia spp. in nomadic herders and their livestock across three provinces from 2014 to 2015. Blood was collected from 397 herders and 2370 livestock, including sheep, goats, cattle, horses and camels. Antibodies against Anaplasma spp. and SFG Rickettsia were determined by indirect immunofluorescence using commercially available slides coated with Anaplasma phagocytophilum and Rickettsia rickettsii antigens. Logistic regression was used to determine if the odds of previous exposure differed by gender, location, and species, with or without adjustment for age. To examine the association between seroprevalence and environmental variables we used ArcGIS to circumscribe the five major clusters where human and animal data were collected. Anaplasma spp. exposure was detected in 37.3% (136/365) of humans and 47.3% (1120/2370) of livestock; SFG Rickettsia exposure was detected in 19.5% (73/374) humans and 20.4% (478/2342) livestock. Compared to the southern province (aimag) of Dornogovi, located in the Gobi Desert, humans were significantly more likely to be exposed to Anaplasma spp. and SFG Rickettsia in the northern provinces of Tov (OR=7.3, 95% CI: 3.5, 15.1; OR=3.3, 95% CI: 1.7, 7.5), and Selenge (OR=6.9, 95% CI: 3.4, 14.0; OR=2.2, 95% CI: 1.1, 4.8). The high seroprevalence of Anaplasma spp. and SFG Rickettsia in humans and livestock suggests that exposure to tick-borne pathogens may be common in herders and livestock in Mongolia, particularly in the more northern regions of the country. Until more is known about these pathogens in Mongolia, physicians and veterinarians in the countryside should consider testing for Anaplasma and SFG Rickettsia infections and treating clinically compatible cases, while public health authorities should expand surveillance efforts for these
Berthová, Lenka; Slobodník, Vladimír; Slobodník, Roman; Olekšák, Milan; Sekeyová, Zuzana; Svitálková, Zuzana; Kazimírová, Mária; Špitalská, Eva
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.
Zemtsova, Galina E; Killmaster, Lindsay F; Montgomery, Merrill; Schumacher, Lauren; Burrows, Matt; Levin, Michael L
Ticks of the genus Dermacentor are known vectors of rickettsial pathogens in both the Old World and New World. In North America, Dermacentor variabilis and D. andersoni are vectors of Rickettsia rickettsii, while in Europe, D. marginatus and D. reticulatus transmit R. slovaca and R. raoultii, respectively. Neither the presence of R. slovaca in the Americas nor the ability of American tick species to maintain this pathogen have been reported. Here we describe detection of Rickettsia genetically identical to R. slovaca in D. variabilis, its molecular characterization, assessment of pathogenicity to guinea pigs, and vector competence of D. variabilis ticks. Ticks from a laboratory colony of D. variabilis, established from wild ticks and maintained on naïve NZW rabbits, tested positive for spotted fever group (SFG) Rickettsia by PCR. Analysis of 17 kDa gltA, rpoB, ompA, ompB, and sca4 genes revealed 100% identity to R. slovaca sequences available in the GenBank. New Zealand white rabbits fed upon by infected ticks seroconverted to SFG Rickettsia. Guinea pigs inoculated with the Rickettsia culture or infested by the infected ticks developed antibodies to SFG Rickettsia. The intensity of clinical signs and immune response were dependent on dose and route of infection. The identified Rickettsia was detected in all life stages of D. variabilis ticks, confirming transstadial and transovarial transmission. Thirty-six percent of uninfected larvae co-fed with infected nymphs on guinea pigs were PCR-positive and able to pass rickettsia to at least 11.7% of molted nymphs. To our knowledge, this is a first report of identification of a European pathogen R. slovaca or a highly similar agent in the American dog tick, D. variabilis. Considering pathogenicity of R. slovaca in humans, further laboratory and field studies are warranted to assess the relevance of the above findings to the public health and epidemiology of SFG rickettsioses in the United States.
Moerbeck, Leonardo; Vizzoni, Vinícius F; Machado-Ferreira, Erik; Cavalcante, Robson C; Oliveira, Stefan V; Soares, Carlos A G; Amorim, Marinete; Gazêta, Gilberto S
Rickettsioses are re-emerging vector-borne zoonoses with a global distribution. Recently, Rickettsia sp. strain Atlantic rainforest has been associated with new human spotted-fever (SF) cases in Brazil, featuring particular clinical signs: eschar formation and lymphadenopathy. These cases have been associated with the tick species, Amblyomma ovale From 2010 until 2015, the Brazilian Health Department confirmed 11 human SF cases in the Maciço de Baturité region, Ceará, Brazil. The present study reports the circulation of Rickettsia spp. in vectors from this entirely new endemic area for SF. A total of 1,727 ectoparasites were collected in this area from the environment, humans, and wild and domestic animals. Samples (n = 887) were screened by polymerase chain reaction (PCR), targeting the gltA and ompA rickettsial genes. Sequencing and phylogenetic analyses of gltA gene amplicons were carried out for 13 samples positive for both screening PCRs. Fragments of gltA and ompA from three samples were cloned, sequenced, and analyzed further. A. ovale and Rhipicephalus sanguineus specimens, collected from dogs, were found to be infected with Rickettsia sp. str. Atlantic rainforest, suggesting the importance of dogs in the epidemic cycle. Candidatus Rickettsia andeanae, Rickettsia felis, and Rickettsia bellii were also found infecting ticks and fleas in five municipalities, demonstrating the broad diversity of rickettsiae in circulation in the studied area. This study reports, for the first time, evidence of infection with Rickettsia sp. strain Atlantic rainforest in A. ovale and R. sanguineus in Ceará, and Ca. R. andeanae in an Atlantic rainforest environment of Brazil. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
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.
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prompted in part by the growth of the anti-apartheid movement. ... showing a new degree of organizational capacity and power in South Africa and among .... leading institutions in the generation and application of new knowledge to meet.
Peniche-Lara, Gaspar; Ruiz-Piña, Hugo A; Reyes-Novelo, Enrique; Dzul-Rosado, Karla; Zavala-Castro, Jorge
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.
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
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.
Full Text Available Termination of transcription is an important component of bacterial gene expression. However, little is known concerning this process in the obligate intracellular pathogen and model for reductive evolution, Rickettsia prowazekii. To assess transcriptional termination in this bacterium, transcripts of convergent gene pairs, some containing predicted intrinsic terminators, were analyzed. These analyses revealed that, rather than terminating at a specific site within the intervening region between the convergent genes, most of the transcripts demonstrated either a lack of termination within this region, which generated antisense RNA, or a putative non-site-specific termination that occurred throughout the intervening sequence. Transcripts terminating at predicted intrinsic terminators, as well as at a putative Rho-dependant terminator, were also examined and found to vary based on the rickettsial host environment. These results suggest that transcriptional termination, or lack thereof, plays a role in rickettsial gene regulation.
Fernanda Aparecida Nieri-Bastos
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.
Unsworth, Nathan B; Stenos, John; Graves, Stephen R; Faa, Antony G; Cox, G Erika; Dyer, John R; Boutlis, Craig S; Lane, Amanda M; Shaw, Matthew D; Robson, Jennifer; Nissen, Michael D
Australia has 4 rickettsial diseases: murine typhus, Queensland tick typhus, Flinders Island spotted fever, and scrub typhus. We describe 7 cases of a rickettsiosis with an acute onset and symptoms of fever (100%), headache (71%), arthralgia (43%), myalgia (43%), cough (43%), maculopapular/petechial rash (43%), nausea (29%), pharyngitis (29%), lymphadenopathy (29%), and eschar (29%). Cases were most prevalent in autumn and from eastern Australia, including Queensland, Tasmania, and South Australia. One patient had a history of tick bite (Haemaphysalis novaeguineae). An isolate shared 99.2%, 99.8%, 99.8%, 99.9%, and 100% homology with the 17 kDa, ompA, gltA, 16S rRNA, and Sca4 genes, respectively, of Rickettsia honei. This Australian rickettsiosis has similar symptoms to Flinders Island spotted fever, and the strain is genetically related to R. honei. It has been designated the "marmionii" strain of R. honei, in honor of Australian physician and scientist Barrie Marmion.
Full Text Available Abstract Background Continuous culture of tick cell lines has proven a valuable asset in isolating and propagating several different vector-borne pathogens, making it possible to study these microorganisms under laboratory conditions and develop serological tests to benefit public health. We describe a method for effective, cost- and labor-efficient isolation and propagation of Rickettsia raoultii using generally available laboratory equipment and Rhipicephalus microplus cells, further demonstrating the usefulness of continuous tick cell lines. R. raoultii is one of the causative agents of tick-borne lymphadenopathy (TIBOLA and is, together with its vector Dermacentor reticulatus, emerging in novel regions of Europe, giving rise to an increased threat to general public health. Methods Dermacentor reticulatus ticks were collected in the Donau-Auen (Lobau national park in Vienna, Austria. The hemolymph of ten collected ticks was screened by PCR-reverse line blot for the presence of rickettsial DNA. A single tick tested positive for R. raoultii DNA and was used to infect Rhipicephalus microplus BME/CTVM2 cells. Results Sixty-five days after infection of the tick-cell line with an extract from a R. raoultii-infected tick, we observed intracellular bacteria in the cultured cells. On the basis of microscopy we suspected that the intracellular bacteria were a species of Rickettsia; this was confirmed by several PCRs targeting different genes. Subsequent sequencing showed 99–100 % identity with R. raoultii. Cryopreservation and resuscitation of R. raoultii was successful. After 28 days identical intracellular bacteria were microscopically observed. Conclusions R. raoultii was successfully isolated and propagated from D. reticulatus ticks using R. microplus BME/CTVM2 cells. The isolated strain shows significant molecular variation compared to currently known sequences. Furthermore we show for the first time the successful cryopreservation and
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.
Gong, Wenping; Xiong, Xiaolu; Qi, Yong; Jiao, Jun; Duan, Changsong; Wen, Bohai
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. PMID:24950252
Wijnveld, Michiel; Schötta, Anna-Margarita; Pintér, Adriano; Stockinger, Hannes; Stanek, Gerold
Continuous culture of tick cell lines has proven a valuable asset in isolating and propagating several different vector-borne pathogens, making it possible to study these microorganisms under laboratory conditions and develop serological tests to benefit public health. We describe a method for effective, cost- and labor-efficient isolation and propagation of Rickettsia raoultii using generally available laboratory equipment and Rhipicephalus microplus cells, further demonstrating the usefulness of continuous tick cell lines. R. raoultii is one of the causative agents of tick-borne lymphadenopathy (TIBOLA) and is, together with its vector Dermacentor reticulatus, emerging in novel regions of Europe, giving rise to an increased threat to general public health. Dermacentor reticulatus ticks were collected in the Donau-Auen (Lobau) national park in Vienna, Austria. The hemolymph of ten collected ticks was screened by PCR-reverse line blot for the presence of rickettsial DNA. A single tick tested positive for R. raoultii DNA and was used to infect Rhipicephalus microplus BME/CTVM2 cells. Sixty-five days after infection of the tick-cell line with an extract from a R. raoultii-infected tick, we observed intracellular bacteria in the cultured cells. On the basis of microscopy we suspected that the intracellular bacteria were a species of Rickettsia; this was confirmed by several PCRs targeting different genes. Subsequent sequencing showed 99-100 % identity with R. raoultii. Cryopreservation and resuscitation of R. raoultii was successful. After 28 days identical intracellular bacteria were microscopically observed. R. raoultii was successfully isolated and propagated from D. reticulatus ticks using R. microplus BME/CTVM2 cells. The isolated strain shows significant molecular variation compared to currently known sequences. Furthermore we show for the first time the successful cryopreservation and resuscitation of R. raoultii.
Full Text Available Rickettsia conorii conorii is the etiological agent of Mediterranean spotted fever, which is transmitted by the brown dog tick, Rhipicephalus sanguineus. The relationship between the Rickettsia and its tick vector are still poorly understood one century after the first description of this disease.An entomological survey was organized in Algeria to collect ticks from the houses of patients with spotted fever signs. Colonies of R. conorii conorii-infected and non-infected ticks were established under laboratory conditions. Gimenez staining and electron microscopy on the ovaries of infected ticks indicated heavy rickettsial infection. The transovarial transmission of R. conorii conorii in naturally infected Rh. sanguineus ticks was 100% at eleven generations, and the filial infection rate was up to 99% according to molecular analyses. No differences in life cycle duration were observed between infected and non-infected ticks held at 25°C, but the average weight of engorged females and eggs was significantly lower in infected ticks than in non-infected ticks. The eggs, larvae and unfed nymphs of infected and non-infected ticks could not tolerate low (4°C or high (37°C temperatures or long starvation periods. R. conorii conorii-infected engorged nymphs that were exposed to a low or high temperature for one month experienced higher mortality when they were transferred to 25°C than non-infected ticks after similar exposure. High mortality was observed in infected adults that were maintained for one month at a low or high temperature after tick-feeding on rabbits.These preliminary results suggest that infected quiescent ticks may not survive the winter and may help explain the low prevalence of infected Rh. sanguineus in nature. Further investigations on the influence of extrinsic factors on diapaused R. conorii-infected and non-infected ticks are required.
Soliman, Ahmed M; Ahmed, Ashraf M; Shimamoto, Toshi; El-Domany, Ramadan A; Nariya, Hirofumi; Shimamoto, Tadashi
Two Proteus mirabilis strains, designated PmTAN59 and PmKAF126, were isolated from two different Egyptian cities in 2014 and 2015, respectively. PmTAN59 was isolated from a sputum swab from a pneumonia patient in Tanta University Teaching Hospital. PmKAF126 was isolated from a patient with a diabetic foot infection in a hospital in the city of Kafr El-Sheikh. The two isolates were identified with bacterial small ribosomal RNA (16S rRNA) gene amplification and sequencing and tested for antimicrobial sensitivity with a Kirby-Bauer disk diffusion assay. The two strains were resistant to amoxicillin/clavulante, ampicillin, cefotaxime, cefoxitin, ceftriaxone, chloramphenicol, ciprofloxacin, colistin, gentamicin, kanamycin, nalidixic acid, spectinomycin, streptomycin, sulfamethoxazole/trimethoprime, and tetracycline, but sensitive to aztreonam, imipenem, and meropenem. Molecular characterization was used to map the entire backbone, including the multiple antibiotic resistance (MDR) region, of Salmonella genomic island 1 (SGI1). Both isolates carried a structure similar to SGI1, with two different MDR regions corresponding to SGI1-PmABB in PmTAN59 and SGI1-W in PmKAF126. SGI1-PmABB carried an integron of ~1.5kb with a two-gene cassette, aacCA5-aadA7, which confers resistance to gentamicin, streptomycin, and spectinomycin, whereas SGI1-W carried an integron of ~1.9kb containing aadA2-lnuF, which confers resistance to spectinomycin, streptomycin, and lincosamides. PmKAF126 carried the entire SGI1 sequence, however PmTAN59 carried a SGI1 structure with a deletion in the region from ORF S005 to ORF S009 and accompanied by insertion of IS1359 (1258bp). Furthermore, PmTAN59 carried class 2 integron of ~2.2kb containing dfrA1-sat2-aadA1. An ERIC-PCR analysis detected no clonal relationship between the two strains. Molecular screening for other antimicrobial resistance genes and a plasmid analysis indicated that PmTAN59 carried an IncFIB plasmid type. This strain also carried bla
Oriero, Eniyou C; Okebe, Joseph; Jacobs, Jan; Van Geertruyden, Jean-Pierre; Nwakanma, Davis; D'Alessandro, Umberto
New diagnostic tools to detect reliably and rapidly asymptomatic and low-density malaria infections are needed as their treatment could interrupt transmission. Isothermal amplification techniques are being explored for field diagnosis of malaria. In this study, a novel molecular tool (loop-mediated isothermal amplification-LAMP) targeting the apicoplast genome of Plasmodium falciparum was evaluated for the detection of asymptomatic malaria-infected individuals in a rural setting in The Gambia. A blood was collected from 341 subjects (median age 9 years, range 1-68 years) screened for malaria. On site, a rapid diagnostic test (RDT, SD Bioline Malaria Antigen P.f) was performed, thick blood films (TBF) slides for microscopy were prepared and dry blood spots (DBS) were collected on Whatman(®) 903 Specimen collection paper. The TBF and DBS were transported to the field laboratory where microscopy and LAMP testing were performed. The latter was done on DNA extracted from the DBS using a crude (methanol/heating) extraction method. A laboratory-based PCR amplification was done on all the samples using DNA extracted with the Qiagen kit and its results were taken as reference for all the other tests. Plasmodium falciparum malaria prevalence was 37 % (127/341) as detected by LAMP, 30 % (104/341) by microscopy and 37 % (126/341) by RDT. Compared to the reference PCR method, sensitivity was 92 % for LAMP, 78 % for microscopy, and 76 % for RDT; specificity was 97 % for LAMP, 99 % for microscopy, and 88 % for RDT. Area under the receiver operating characteristic (ROC) curve in comparison with the reference standard was 0.94 for LAMP, 0.88 for microscopy and 0.81 for RDT. Turn-around time for the entire LAMP assay was approximately 3 h and 30 min for an average of 27 ± 9.5 samples collected per day, compared to a minimum of 10 samples an hour per operator by RDT and over 8 h by microscopy. The LAMP assay could produce reliable results the same day of the screening. It could
Ismael A. Conti-Díaz
Full Text Available We report three new rickettsiosis human cases in Uruguay. The three clinical cases presented clinical manifestations similar to previous reported cases of Rickettsia parkeri in the United States; that is mild fever (São relatados três novos casos humanos de rickettsiose no Uruguai. Os três casos clínicos apresentam manifestações clínicas semelhantes às descritas em casos de infecção por Rickettsia parkeri previamente relatados nos Estados Unidos, tais como: febre moderada (< 40 ºC, mal-estar, cefaléia, exantema, escara de inoculação no sítio de fixação do carrapato, linfadenopatia regional e ausência de letalidade. Testes sorológicos de absorção de anticorpos com antígenos de R. parkeri e Rickettsia rickettsii, associados à reação de imunofluorescência indireta, sugerem que os pacientes de dois casos foram infectados por R. parkeri. Evidências clínicas e epidemiológicas, associadas com nossas análises sorológicas, sugerem que R. parkeri é o agente etiológico de casos humanos de febre maculosa no Uruguai, uma doença que tem sido reconhecida naquele país como rickettsiose cutâneo-ganglionar.
Full Text Available A lethal case of Brazilian spotted fever (BSF is presented. Clinical features were initially of gastrointestinal involvement and evolved with progression to septic shock, meningoencephalitis and death on the 6th day of illness. Indirect immunofluorescence assay (IFA for spotted fever group rickettsia (SFGR was non-reactive. Diagnosis was confirmed by the polymerase chain reaction (PCR and the nucleotide sequencing of a fragment of the ompA gene showed 100% homology to Rickettsia rickettsii. BSF has not been reported in the city of Rio de Janeiro in the last three decades, and the present description should alert the clinicians to its presence in urban Rio de Janeiro, and to the differential diagnosis with dengue fever, gastroenteritis, leptospirosis and bacterial septic shock, among others.
Muñoz-Leal, Sebastián; Tarragona, Evelina L; Martins, Thiago F; Martín, Claudia M; Burgos-Gallardo, Freddy; Nava, Santiago; Labruna, Marcelo B; González-Acuña, Daniel
Adults of Amblyomma parvitarsum are common ectoparasites of South American camelids of the genera Lama and Vicugna, occuring in highlands of Argentina, Bolivia, Chile, Peru and also in Argentinean Patagonia. Whereas larval stages of this tick are known to feed on small lizards, host records for the nymphal instar have remained unreported. Supported by morphological and molecular analyses, herein we report A. parvitarsum nymphs parasitizing two Liolaemus species (Reptilia: Squamata) in the Andean Plateau of Argentina and Chile. Additionally, by a PCR screening targetting gltA and ompA genes, DNA of Rickettsia was detected in one of the collected nymphs. Obtained sequences of this agent were identical to a recent Rickettsia sp. described infecting adults of this tick species in Chile and Argentina.
This paper reports that South Africa's main reason for entering the international nuclear market is, and always has been, to sell its uranium abroad. From 1939-45 South Africa took part in the war against Nazi Germany, and the South African government of the time sought to help the Allied war effort in all ways that were practical. Later, during the Cold War, it tried to help build up the West's nuclear arsenal. In 1944, the British government secretly asked General Smuts---prime minister of South Africa since 1939 and a member of Churchill's War Cabinet---to survey South Africa's deposits of uranium. The survey, carried out with U.S. and British help, showed that the deposits were large, generally low-grade, but, in most cases, associated with gold and therefore could be profitably mined. In 1951, South Africa became a significant producer, with lucrative contracts for the sale of all its output to the U.S.-U.K.-Canada Joint Development Agency and one of the three main suppliers to the U.S. nuclear weapons program. In time, government controls eased and uranium production and marketing became a purely commercial operation
Raczniak, Gregory A; Kato, Cecilia; Chung, Ida H; Austin, Amy; McQuiston, Jennifer H; Weis, Erica; Levy, Craig; Carvalho, Maria da Gloria S; Mitchell, Audrey; Bjork, Adam; Regan, Joanna J
Rocky Mountain spotted fever, a tick-borne disease caused by Rickettsia rickettsii, is challenging to diagnose and rapidly fatal if not treated. We describe a decedent who was co-infected with group A β-hemolytic streptococcus and R. rickettsii. Fatal cases of Rocky Mountain spotted fever may be underreported because they present as difficult to diagnose co-infections. © The American Society of Tropical Medicine and Hygiene.
Roth, Tara; Lane, Robert S; Foley, Janet
Francisella tularensis and Rickettsia spp. have been cultured from Haemaphysalis leporispalustris Packard, but their prevalence in this tick has not been determined using modern molecular methods. We collected H. leporispalustris by flagging vegetation and leaf litter and from lagomorphs (Lepus californicus Gray and Sylvilagus bachmani (Waterhouse)) in northern California. Francisella tularensis DNA was not detected in any of 1,030 ticks tested by polymerase chain reaction (PCR), whereas 0.4% of larvae tested in pools, 0 of 117 individual nymphs, and 2.3% of 164 adult ticks were PCR-positive for Rickettsia spp. Positive sites were Laurel Canyon Trail in Tilden Regional Park in Alameda Contra Costa County, with a Rickettsia spp. prevalence of 0.6% in 2009, and Hopland Research and Extension Center in Mendocino County, with a prevalence of 4.2% in 1988. DNA sequencing revealed R. felis, the agent of cat-flea typhus, in two larval pools from shaded California bay and live oak leaf litter in Contra Costa County and one adult tick from a L. californicus in chaparral in Mendocino County. The R. felis in unfed, questing larvae demonstrates that H. leporispalustris can transmit this rickettsia transovarially. Although R. felis is increasingly found in diverse arthropods and geographical regions, prior literature suggests a typical epidemiological cycle involving mesocarnivores and the cat flea, Ctenocephalides felis. To our knowledge, this is the first report of R. felis in H. leporispalustris. Natural infection and transovarial transmission of this pathogen in the tick indicate the existence of a previously undocumented wild-lands transmission cycle that may intersect mesocarnivore-reservoired cycles and collectively affect human health risk. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: email@example.com.
Ixodes ricinus, the most commonly observed tick species in Poland, is known vector of microorganisms pathogenic for humans as TBE virus, Borrelia burgdorferi s.1., Anaplasma phagocytophilum and Babesia sp. in this country. Our study aimed to find out whether this tick can also transmit also rickettsiae of the spotted fever group (SFG). DNA extracts from 560 ticks (28 females, 34 males, and 488 nymphs) collected in different wooded areas in northern Poland were examined by PCR for the detection of Rickettsia sp., using a primer set RpCS.877p and RpCS.1258n designated to amplify a 381-bp fragment of gltA gene. A total of 2.9% ticks was found to be positive. The percentage of infected females and males was comparable (10.5% and 11.8%, respectively) and 6.6-7.6 times higher than in nymphs (1.6%). Sequences of four PCR-derived DNA fragments (acc. no. DQ672603) demonstrated 99% similarity with the sequence of Rickettsia helvetica deposited in GenBank. The results obtained suggest the possible role of I. ricinus as a source of a microorganism, which recently has been identified as an agent of human rickettsioses in Europe.
Silva, Arannadia Barbosa; Duarte, Myrian Morato; da Costa Cavalcante, Robson; de Oliveira, Stefan Vilges; Vizzoni, Vinicius Figueiredo; de Lima Duré, Ana Íris; de Melo Iani, Felipe Campos; Machado-Ferreira, Erik; Gazêta, Gilberto Salles
In Brazil, Spotted Fever (SF) is caused by Rickettsia rickettsii and Rickettsia parkeri strain Atlantic Forest. In recent years, several human cases of a milder SF have been reported from the Maciço de Baturité region of Ceará State. Previous studies in this region found R. parkeri strain Atlantic Forest to be present in Rhipicephalus sanguineus sensu lato and Amblyomma ovale ticks. The present study isolated and identified the Rickettsia spp. present in this new endemic area in Brazil. In March 2015, R. sanguineus s.l. and A. ovale were collected in rural areas of the Maciço de Baturité region, and subjected to the isolation technique. A bacterium was isolated from one R. sanguineus s.l., which phylogenetic analysis clustered to the R. rickettsii group. In conclusion, R. rickettsii bacteria is circulating in the studied area and may in future have an impact on the clinical diagnoses and consequently cause changes in the profile of the disease in the region. In addition, we suggest the increase of epidemiological and environmental surveillance in the area, in order to prevent Brazilian Spotted Fever cases. Copyright © 2017. Published by Elsevier B.V.
Trout Fryxell, Rebecca T; Hendricks, Brain M; Pompo, Kimberly; Mays, Sarah E; Paulsen, Dave J; Operario, Darwin J; Houston, Allan E
Ehrlichiosis and rickettsiosis are two common bacterial tick-borne diseases in the southeastern United States. Ehrlichiosis is caused by ehrlichiae transmitted by Amblyomma americanum and rickettsiosis is caused by rickettsiae transmitted by Amblyomma maculatum and Dermacentor variabilis. These ticks are common and have overlapping distributions in the region. The objective of this study was to identify Anaplasma, Ehrlichia, and Rickettsia species associated with questing ticks in a Rocky Mountain spotted fever (RMSF) hotspot, and identify habitats, time periods, and collection methods for collecting questing-infected ticks. Using vegetation drags and CO 2 -baited traps, ticks were collected six times (May-September 2012) from 100 sites (upland deciduous, bottomland deciduous, grassland, and coniferous habitats) in western Tennessee. Adult collections were screened for Anaplasma and Ehrlichia (simultaneous polymerase chain reaction [PCR]) and Rickettsia using genus-specific PCRs, and resulting positive amplicons were sequenced. Anaplasma and Ehrlichia were only identified within A. americanum (Ehrlichia ewingii, Ehrlichia chaffeensis, Panola Mountain Ehrlichia, and Anaplasma odocoilei sp. nov.); more Ehrlichia-infected A. americanum were collected at the end of June regardless of habitat and collection method. Rickettsia was identified in three tick species; "Candidatus Rickettsia amblyommii" from A. americanum, R. parkeri and R. andeanae from A. maculatum, and R. montanensis ( = montana) from D. variabilis. Overall, significantly more Rickettsia-infected ticks were identified as A. americanum and A. maculatum compared to D. variabilis; more infected-ticks were collected from sites May-July and with dragging. In this study, we report in the Tennessee RMSF hotspot the following: (1) Anaplasma and Ehrlichia are only found in A. americanum, (2) each tick species has its own Rickettsia species, (3) a majority of questing-infected ticks are collected May-July, (4) A
Scheid, Patrick; Speck, Stephanie; Schwarzenberger, Rafael; Litzinger, Mark; Balczun, Carsten; Dobler, Gerhard
Ixodes ricinus is a well-known vector of different human pathogens including Rickettsia helvetica. The role of wild mammals in the distribution and probable maintenance of Rickettsia in nature is still to be determined. We therefore investigated various parasites from different wild mammals as well as companion animals for the presence of Rickettsia. A total of 606 I. ricinus, 38 Cephenemyia stimulator (botfly larvae), one Dermacentor reticulatus, 24 Haematopinus suis (hog lice) and 30 Lipoptena cervi (deer flies) were collected from free-ranging animals during seasonal hunting, and from companion animals. Sample sites included hunting leases at three main sampling areas and five additional areas in West and Central Germany. All collected parasites were screened for Rickettsia spp. and I. ricinus were investigated for tick-borne encephalitis virus (TBEV) in addition. While no TBEV was detected, the minimum infection rate (MIR) of I. ricinus with Rickettsia was 4.1% referring to all sampling sites and up to 6.9% at the main sampling site in Koblenz area. Sequencing of a fragment of the ompB gene identified R. helvetica. Approximately one third (29.5%) of the animals carried Rickettsia-positive ticks and the MIR in ticks infesting wild mammals ranged from 4.1% (roe deer) to 9.5%. These data affirm the widespread distribution of R. helvetica in Germany. One botfly larva from roe deer also harboured R. helvetica. Botfly larvae are obligate parasites of the nasal cavity, pharynx and throat of cervids and feed on cell fragments and blood. Based on this one might hypothesise that R. helvetica likely induces rickettsemia in cervids thus possibly contributing to maintenance and distribution of this rickettsia in the field. Copyright © 2016 Elsevier GmbH. All rights reserved.
similarity was observed between traditional aromatic rice Basmati 370 and the landrace Gambiaka. Nigeria. .... inheritance, abundance and extensive genome coverage ... market value, 4 landraces Gambiaka well spread in Africa, TS2 a.
Lack, Justin B; Lange, Jeremy D; Tang, Alison D; Corbett-Detig, Russell B; Pool, John E
The Drosophila Genome Nexus is a population genomic resource that provides D. melanogaster genomes from multiple sources. To facilitate comparisons across data sets, genomes are aligned using a common reference alignment pipeline which involves two rounds of mapping. Regions of residual heterozygosity, identity-by-descent, and recent population admixture are annotated to enable data filtering based on the user's needs. Here, we present a significant expansion of the Drosophila Genome Nexus, which brings the current data object to a total of 1,121 wild-derived genomes. New additions include 305 previously unpublished genomes from inbred lines representing six population samples in Egypt, Ethiopia, France, and South Africa, along with another 193 genomes added from recently-published data sets. We also provide an aligned D. simulans genome to facilitate divergence comparisons. This improved resource will broaden the range of population genomic questions that can addressed from multi-population allele frequencies and haplotypes in this model species. The larger set of genomes will also enhance the discovery of functionally relevant natural variation that exists within and between populations. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
NESDA: Network for Environment and Sustainable Development in Africa .... Some of the key natural resources of the region are transboundary—case of surface ..... The goals of the present study on the risk-sharing approach to regional ...... The reserve includes a World Heritage Site (Djoudj) and 5 Ramsar sites (Djoudj,.
Africa Development is the quarterly bilingual journal of CODESRIA. It is a social science journal whose major focus is on issues which are central to the development of society. Its principal objective is to provide a forum for the exchange of ideas among African scholars from a variety of intellectual persuasions and various ...
This true-color image of South Africa was acquired on May 14, 2000, by NASA's Moderate-resolution Imaging Spectroradiometer, or MODIS. The image was produced using a combination of the sensor's 250-m and 500-m resolution visible wavelength bands. As part of the opening ceremony to begin the joint U.S.-South Africa SAFARI Field Experiment, NASA presented print copies of this image as GIFts to Dr. Ben Ngubane, Minister of Arts, Science and Technology, and Honorable Advocate Ngoaka Ramathlodi, Premier of the Northern Province, South Africa. The area shown in this image encompasses seven capital cities and a number of the region's distinctive geological features can be seen clearly. Toward the northern (top) central part of the image, the browns and tans comprise the Kalahari Desert of southern Botswana. The Tropic of Capricorn runs right through the heart of the Kalahari and the Botswanan capital city of Gaborone sits on the Limpopo River, southeast of the Kalahari. Along the western coastline of the continent is the country of Namibia, where the Namib Desert is framed against the sea by the Kaokoveld Mountains. The Namibian capital of Windhoek is obscured by clouds. Looking closely in the center of the image, the Orange River can be seen running from east to west, demarcating the boundary between Namibia and South Africa. On the southwestern corner of the continent is the hook-like Cape of Good Hope peninsula and Cape Town, the parliamentary capital of South Africa. Running west to east away from Cape Town are the Great Karroo Mountains. The shadow in this image conveys a sense of the very steep grade of the cliffs along the southern coast of South Africa. Port Elizabeth sits on the southeasternmost point of South Africa, and a large phytoplankton bloom can be seen in the water about 100 miles east of there. Moving northward along the east coast, the Drakensberg Mountains are visible. The two small nations of Lesotho and Swaziland are in this region, completely
Melles Heloisa Helena Barbosa
Full Text Available Embora o diagnóstico da febre maculosa baseie-se em sinais e sintomas característicos, o mesmo requer confirmação laboratorial, pois existem alguns diagnósticos diferenciais possíveis como meningococcemia, leptospirose, infecção por enterovírus e febre tifóide. A confirmação laboratorial pode ser feita através da pesquisa de anticorpos específicos, possível somente alguns dias após o aparecimento da doença, através do isolamento do agente em amostras de sangue e/ou biópsia de pele, e ainda, de amostras de carrapatos coletados do paciente ou de animais reservatório. O isolamento a partir de sangue ou biópsia de pele resulta em diagnóstico precoce da doença, pois na fase de rickettsemia ainda não há anticorpos detectáveis no sangue. Assim, com o objetivo de facilitar o diagnóstico precoce da febre maculosa, estabelecemos um método de isolamento de rickettsia em cultura de células vero. Para a padronização foi inoculada amostra padrão de Rickettsia rickettsii, cepa Sheyla Smith, cedida pelo CDC. A identificação foi feita através da reação de imunofluorescência indireta. A presença de microrganismos verdes fluorescentes visualizados no interior do citoplasma das células caracterizou o crescimento do agente. Posteriormente, a metodologia foi confirmada pelo isolamento do agente da febre maculosa em amostras de biópsia de pele de paciente proveniente de área endêmica no Estado de São Paulo, bem como, de amostras de carrapato do gênero Amblyomma, considerado o reservatório e transmissor da doença no Brasil.
Abramowicz, K F; Wekesa, J W; Nwadike, C N; Zambrano, M L; Karpathy, S E; Cecil, D; Burns, J; Hu, R; Eremeeva, M E
Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
Fill, Mary-Margaret A; Moncayo, Abelardo C; Bloch, Karen C; Dunn, John R; Schaffner, William; Jones, Timothy F
Spotted fever group (SFG) rickettsioses are endemic in Tennessee, with ∼2,500 cases reported during 2000-2012. Because of this substantial burden of disease, we performed a three-part evaluation of Tennessee's routine surveillance for SFG rickettsioses cases and deaths to assess the system's effectiveness. Tennessee Department of Health (TDH) SFG rickettsioses surveillance records were matched to three patient series: 1) patients with positive serologic specimens from a commercial reference laboratory during 2010-2011, 2) tertiary medical center patients with positive serologic tests during 2007-2013, and 3) patients identified from death certificates issued during 1995-2014 with SFG rickettsiosis-related causes of death. Chart reviews were performed and patients were classified according to the Council of State and Territorial Epidemiologists' case definition. Of 254 SFG Rickettsia -positive serologic specimens from the reference laboratory, 129 (51%) met the case definition for confirmed or probable cases of rickettsial disease after chart review. The sensitivity of the TDH surveillance system to detect cases was 45%. Of the 98 confirmed or probable cases identified from the medical center, the sensitivity of the TDH surveillance system to detect cases was 34%. Of 27 patients identified by death certificates, 12 (44%) were classified as confirmed or probable cases; four (33%) were reported to TDH, but none were correctly identified as deceased. Cases of SFG rickettsioses were underreported and fatalities not correctly identified. Efforts are needed to improve SFG rickettsiosis surveillance in Tennessee.
GUO Qionglin; JIA Weizhang; HAN Xianpu; CAI Taozhen; GONG Xiaoning; SUN Xiaofeng
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.
Paddock, Christopher D; Denison, Amy M; Lash, R Ryan; Liu, Lindy; Bollweg, Brigid C; Dahlgren, F Scott; Kanamura, Cristina T; Angerami, Rodrigo N; Pereira dos Santos, Fabiana C; Brasil Martines, Roosecelis; Karpathy, Sandor E
Rocky Mountain spotted fever (RMSF), a tick-borne zoonosis caused by Rickettsia rickettsii, is among the deadliest of all infectious diseases. To identify the distribution of various genotypes of R. rickettsii associated with fatal RMSF, we applied molecular typing methods to samples of DNA extracted from formalin-fixed, paraffin-embedded tissue specimens obtained at autopsy from 103 case-patients from seven countries who died of RMSF. Complete sequences of one or more intergenic regions were amplified from tissues of 30 (29%) case-patients and revealed a distribution of genotypes consisting of four distinct clades, including the Hlp clade, regarded previously as a non-pathogenic strain of R. rickettsii. Distinct phylogeographic patterns were identified when composite case-patient and reference strain data were mapped to the state and country of origin. The phylogeography of R. rickettsii is likely determined by ecological and environmental factors that exist independently of the distribution of a particular tick vector. © The American Society of Tropical Medicine and Hygiene.
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.
Full Text Available Queensland tick typhus (QTT; Rickettsia australis is an important cause of community-acquired acute febrile illness in eastern Australia. Cases of QTT were identified retrospectively from 2000 to 2015 at five sites in Northern Brisbane through a pathology database. Those included had a fourfold rise in spotted fever group (SFG-specific serology, a single SFG-specific serology ≥ 256 or SFG-specific serology ≥ 128 with a clinically consistent illness. Cases were excluded on the basis of clinical unlikelihood of QTT infection. Thirty-six cases were included. Fever was found in 34/36 (94% patients. Rash occurred in 83% of patients with maculopapular being the dominant morphology (70%. Thrombocytopenia, lymphopenia, and raised transaminases were common and occurred in 58%, 69%, and 89% of patients, respectively. Thirty-one of 36 (86% patients received antibiotic therapy (usually doxycycline and the time to correct antibiotic (from admission ranged from 3 to 120 h (mean 45.5 h. Four of 36 (11% required intensive care unit (ICU admission for severe sepsis and end-organ support. There were no deaths. QTT has a wide range of clinical and laboratory features. Early and appropriate antimicrobial therapy is important and may prevent severe disease. Further prospective studies are required to identify factors associated with severe infection and sepsis.
Seijo, Alfredo; Giamperetti, Sergio; Ortiz Mayor, Sonia M; González, María B; Ortega, Eugenia S; González, Rossana C
On the fifth day after leaving the Parque Nacional El Rey, province of Salta, Argentina, where she made rural tourism, a woman of Italian origin, aged 47, developed an acute fever followed by a petechial and purpuric rash that progressed rapidly to multiorgan failure. She died on the sixth day after hospitalization. There were references to tick bites and a skin lesion similar to tache noire was found. The autopsy showed generalized vasculitis, ascites, pulmonary edema, acute tubular necrosis and portal centrilobular necrosis. Spleen and liver tissue were processed for PCR Rickettsia spp, based on the detection of the gltA gene. The result was positive. The amplicons obtained were sequenced and the results were compared with the preset sequences on the BLAST program, 99% coinciding with R. rickettsii. The low sensitivity of the health system to recognize this disease and the insufficient information generated from tourism-related media are factors that affect the delay to implement effective treatment and appropriate prevention standards.
Unsworth, Nathan B.; Graves, Stephen R.; Faa, Antony G.; Cox, G. Erika; Dyer, John R.; Boutlis, Craig S.; Lane, Amanda M.; Shaw, Matthew D.; Robson, Jennifer; Nissen, Michael D.
Australia has 4 rickettsial diseases: murine typhus, Queensland tick typhus, Flinders Island spotted fever, and scrub typhus. We describe 7 cases of a rickettsiosis, with an acute onset and symptoms of fever (100%), headache (71%), arthralgia (43%), myalgia (43%), cough (43%), maculopapular/petechial rash (43%), nausea (29%), pharyngitis (29%), lymphadenopathy (29%), and eschar (29%). Cases were most prevalent in autumn and from eastern Australia, including Queensland, Tasmania, and South Australia. One patient had a history of tick bite (Haemaphysalis novaeguineae). An isolate shared 99.2%, 99.8%, 99.8%, 99.9%, and 100% homology with the 17 kDa, ompA, gltA, 16S rRNA, and Sca4 genes, respectively, of Rickettsia honei. This Australian rickettsiosis has similar symptoms to Flinders Island spotted fever, and the strain is genetically related to R. honei. It has been designated the “marmionii” strain of R. honei, in honor of Australian physician and scientist Barrie Marmion. PMID:17553271
This document provides information on the status of institutional and financial arrangements in South Africa for the long term management of HLW and SNF, It includes the following elements: A consistent set of requirements for the technical and legal infrastructure including: funding, liability, institutional control, records management, and research activities; An organizational structure with clearly defined responsibilities; and Provisions for participation by interested parties in decisions and outcomes
Matheus Dias Cordeiro
Full Text Available ABSTRACT. Cordeiro M.D., Raia V.A., Valim J.R.A., Castro G.N.S., Souza C.E. & Fonseca A.H. [Frequency of antibodies class IgG anti-Rickettsia rickettsii in horses of Universidade Federal Rural do Rio de Janeiro, Seropédica campus.] Frequência de anticorpos da classe IgG anti-Rickettsia rickettsii em equinos na Universidade Federal Rural do Rio de Janeiro, Campus Seropédica. Revista Brasileira de Medicina Veterinária, 37(1:78-82, 2015. Departamento de Epidemiologia e Saúde Pública, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Campus Seropédica, BR 465, Km7, Seropédica, RJ 23890-000, Brasil. E-mail: firstname.lastname@example.org The aim of this study was to verify, through the indirect immunofluorescence assay (IFA, the frequency of anti-Rickettsia rickettsii antibodies in horses at Universidade Federal Rural do Rio de Janeiro (UFRRJ Seropédica campus, state of Rio de Janeiro. We analyzed serum samples from 42 horses from Department of Breeding Equine of UFRRJ. All samples were tested using fixed slides with antigens for R. rickettsii, Rickettsia rhipicephali and Rickettsia parkeri. We observed an overall prevalence of Rickettsia spp. 83.33% (35/42. For the agent R. rickettsii revealed a prevalence of 66.67% (28/42, still being categorized in titers of 1:64 (19/28 and 1:128 (9/28. Nine of the 28 positives horses for R. rickettsii (21.43% were no reactive to other agents, with titers 1:64 (8/9 and 1:128 (1/9. The only tick species found parasitizing horses on the campus of UFRRJ during the collection period were Amblyomma cajennense and Dermacentor nitens. The UFRRJ presents an environment that provides a ideal epidemiological niche for the permanence of Rickettsia bacteria. The high prevalence found in this study indicates that attention to epidemiological agent of Brazilian Spotted Fever in the study area is of utmost importance. The aim of this study was to verify, through the indirect immunofluorescence assay (IFA, the
Krawczak, Felipe S; Agostinho, Washington C; Polo, Gina; Moraes-Filho, Jonas; Labruna, Marcelo B
In 2010, a novel spotted fever group rickettsiosis was reported in the Atlantic rainforest coast of Brazil. The etiological agent was identified as Rickettsia sp. strain Atlantic rainforest, and the tick Amblyomma ovale was incriminated as the presumed vector. The present study evaluated under laboratory conditions four colonies of A. ovale: two started from engorged females that were naturally infected by Rickettsia sp. strain Atlantic rainforest (designated as infected groups); the two others started from noninfected females (designated as control groups). All colonies were reared in parallel from F0 engorged female to F2 unfed nymphs. Tick-naïve vesper mice (Calomys callosus) or domestic rabbits were used for feeding of each tick stage. Rickettsia sp. strain Atlantic rainforest was preserved by transstadial maintenance and transovarial transmission in A. ovale ticks for at least 2 generations (from F0 females to F2 nymphs), because nearly 100% of the tested larvae, nymphs, and adults from the infected groups were shown by PCR to contain rickettsial DNA. All vesper mice and rabbits infested by larvae and nymphs, and 50% of the rabbits infested by adults from the infected groups seroconverted, indicating that these tick stages were vector competent for Rickettsia sp. strain Atlantic rainforest. Expressive differences in mortality rates and reproductive performance were observed between engorged females from the infected and control groups, as indicated by 75.0% and 97.1% oviposition success, respectively, and significantly lower egg mass weight, conversion efficiency index, and percentage of egg hatching for the infected groups. Our results indicate that A. ovale can act as a natural reservoir for Rickettsia sp. strain Atlantic rainforest. However, due to deleterious effect caused by this rickettsial agent on engorged females, amplifier vertebrate hosts might be necessary for persistent perpetuation of Rickettsia sp. strain Atlantic rainforest in A. ovale under
Overzier, Evelyn; Pfister, Kurt; Thiel, Claudia; Herb, Ingrid; Mahling, Monia; Silaghi, Cornelia
In a previous study, our group investigated the Babesia spp. prevalence in questing Ixodes ricinus ticks from nine city parks in South Germany in the years 2009 and 2010. We showed predominant prevalence of B. venatorum (in previous literature also known as Babesia sp. EU1), especially in those parks in a more natural condition and with occurrence of large wild animals, such as roe deer. To obtain longitudinal data and to broaden the knowledge about this pathogen, further investigations were carried out in 2011 and 2012 in four of those city parks. Two additional habitat types were chosen for comparison of prevalence data and species analysis focusing on occurrence of potential reservoir hosts. A total of 10,303 questing I. ricinus were collected in four city parks, a pasture, and a natural area in Bavaria, and a representative number of samples were investigated for prevalence of DNA of Babesia spp. (n=4381) and Rickettsia spp. (n=2186) by PCR. In the natural and pasture area, a significantly higher Babesia spp. prevalence compared to the urban area was detected. The natural area revealed sequences of B. microti, B. venatorum, and B. capreoli. In the pasture and urban habitat, predominantly B. venatorum was found, whereas B. capreoli was less frequent and only one B. microti-infected tick was found. All B. microti sequences were 100% identical to the zoonotic Jena/Germany strain. For Rickettsia spp., the significantly highest prevalence was also detected in the natural and pasture areas, whereas lower prevalence was found in the urban area. Sequence analysis revealed R. helvetica (98%) and R. monacensis (2%). Prevalence rates and occurrence of Babesia spp. and Rickettsia spp. differed in urban, pasture and natural sites, most likely depending on the habitat structure (natural or cultivated) and therefore on the appearance and availability of reservoir hosts like roe deer or small mammals.
Sergio E. Bermúdez
Full Text Available Introducción. Desde mediados del siglo pasado, se conocen en Panamá casos de rickettsiosis, cuando fueron reportados brotes de tifus en ratones y de fiebres manchadas. A partir de entonces, poca información se tiene sobre su prevalencia en este país, lo cual se debe principalmente a que son confundidos con otras enfermedades. Objetivos. El objetivo de este trabajo fue demostrar la presencia de rickettsiosis en humanos provenientes de tres localidades de Panamá, que corresponden a zonas agropecuarias, cercanas a bosques, o que trabajaban en zoológicos. Materiales y métodos. Se escogieron tres localidades para este estudio: Tortí (provincia de Panamá, El Valle de Antón (provincia de Coclé y el Parque Municipal Summit en Ciudad de Panamá. Los voluntarios firmaron un consentimiento informado, además de responder un cuestionario. De cada voluntario se extrajo sangre venosa, la que fue analizada por medio de inmunoflorescencia indirecta, utilizando kits comerciales y láminas sensibilizadas con antígenos cultivados de Rickettsia rickettsii y Rickettsia amblyommii. Resultados. Se tomaron muestras de 97 voluntarios, 25 en Tortí, 37 en El Valle de Antón y 35 en el Parque Municipal Summit. De estos, 38 (39 % de las muestras fueron positivas en algunas de las dos técnicas practicadas: 8 (32 % en Tortí, 18 (48 % en El Valle y 12 (34 % en el Parque Municipal Summit. Conclusión. Se demuestra una alta prevalencia de anticuerpos contra Rickettsia del grupo de las fiebres manchadas en las tres áreas de estudio, además de presentarse evidencia de títulos para Rickettsia del grupo tifus en El Valle de Antón. Estas zonas podrían considerarse como endémicas por rickettsiosis, ya que existen condiciones que permiten el mantenimiento de las mismas. doi: http://dx.doi.org/10.7705/biomedica.v33i0.831
Full Text Available Rickettsia felis, the agent of flea-borne spotted fever, has a cosmopolitan distribution. Its pathogenic role in humans has been demonstrated through molecular and serologic tests in several cases. The cat flea (Ctenocephalides felis is considered the main reservoir and the biological vector. The aim of this study was to assess the presence and occurrence of R. felis in fleas collected from dogs and cats in various sites of Palermo (Sicily. Between August and October 2012, 134 fleas were collected from 42 animals: 37 fleas from 13 dogs and 97 fleas from 29 cats. Two species of fleas were identified: 132 Ctenocephalides felis (98.51% collected on all animals and only two C. canis (1.49% on one dog. Out of 132 C. felis, 34 (25.76%, 12 from dogs (32.43% and 22 (22.68% from cats, were positive for R. felis DNA by a polymerase chain reaction (PCR, confirmed by sequencing. The only two C. canis fleas were negative. About half of examined animals (47.62%, 20/42 were infested with at least one infected flea; in particular 46.15% of dogs (6/13 and 48.28% of cats (14/29. It seems that in the Palermo district there is a peri-domestic cycle, with a relatively high prevalence of R. felis infection in the cat flea, an insect widely diffused in home environments and which can frequently bite humans. The results also suggest that R. felis should be considered in the human differential diagnosis of any spotted-like fever or febrile illness without a clear source of infection in Sicily, especially if the patient is known to have been exposed to flea bites.
Paddock, Christopher D; Finley, Richard W; Wright, Cynthia S; Robinson, Howard N; Schrodt, Barbara J; Lane, Carole C; Ekenna, Okechukwu; Blass, Mitchell A; Tamminga, Cynthia L; Ohl, Christopher A; McLellan, Susan L F; Goddard, Jerome; Holman, Robert C; Openshaw, John J; Sumner, John W; Zaki, Sherif R; Eremeeva, Marina E
Rickettsia parkeri rickettsiosis, a recently identified spotted fever transmitted by the Gulf Coast tick (Amblyomma maculatum), was first described in 2004. We summarize the clinical and epidemiological features of 12 patients in the United States with confirmed or probable disease attributable to R. parkeri and comment on distinctions between R. parkeri rickettsiosis and other United States rickettsioses. Clinical specimens from patients in the United States who reside within the range of A. maculatum for whom an eschar or vesicular rash was described were evaluated by > or =1 laboratory assays at the Centers for Disease Control and Prevention (Atlanta, GA) to identify probable or confirmed infection with R. parkeri. During 1998-2007, clinical samples from 12 patients with illnesses epidemiologically and clinically compatible with R. parkeri rickettsiosis were submitted for diagnostic evaluation. Using indirect immunofluorescence antibody assays, immunohistochemistry, polymerase chain reaction assays, and cell culture isolation, we identified 6 confirmed and 6 probable cases of infection with R. parkeri. The aggregate clinical characteristics of these patients revealed a disease similar to but less severe than classically described Rocky Mountain spotted fever. Closer attention to the distinct clinical features of the various spotted fever syndromes that exist in the United States and other countries of the Western hemisphere, coupled with more frequent use of specific confirmatory assays, may unveil several unique diseases that have been identified collectively as Rocky Mountain spotted fever during the past century. Accurate assessments of these distinct infections will ultimately provide a more valid description of the currently recognized distribution, incidence, and case-fatality rate of Rocky Mountain spotted fever.
Full Text Available MicroRNAs (miRNAs mediate gene silencing by destabilization and/or translational repression of target mRNA. Infection of human microvascular endothelial cells as primary targets of Rickettsia rickettsii, the etiologic agent of Rocky Mountain spotted fever, triggers host responses appertaining to alterations in cellular gene expression. Microarray-based profiling of endothelial cells infected with R. rickettsii for 3 or 24 h revealed differential expression of 33 miRNAs, of which miRNAs129-5p, 200a-3p, 297, 200b-3p, and 595 were identified as the top five up-regulated miRNAs (5 to 20-fold, p ≤ 0.01 and miRNAs 301b-3p, 548a-3p, and 377-3p were down-regulated (2 to 3-fold, p ≤ 0.01. Changes in the expression of selected miRNAs were confirmed by q-RT-PCR in both in vitro and in vivo models of infection. As potential targets, expression of genes encoding NOTCH1, SMAD2, SMAD3, RIN2, SOD1, and SOD2 was either positively or negatively regulated. Using a miRNA-specific mimic or inhibitor, NOTCH1 was determined to be a target of miRNA 200a-3p in R. rickettsii-infected human dermal microvascular endothelial cells (HMECs. Predictive interactome mapping suggested the potential for miRNA-mediated modulation of regulatory gene networks underlying important host cell signaling pathways. This first demonstration of altered endothelial miRNA expression provides new insights into regulatory elements governing mechanisms of host responses and pathogenesis during human rickettsial infections.
Full Text Available Brazilian Spotted Fever (BSF, caused by the bacterium Rickettsia rickettsii, is the tick-borne disease that generates the largest number of human deaths in the world. In Brazil, the current increase of BSF human cases has been associated with the presence and expansion of capybaras Hydrochoerus hydrochaeris, which act as primary hosts for the tick Amblyomma sculptum, vector of the R. rickettsii in this area.We proposed a semi-discrete-time stochastic model to evaluate the role of capybaras in the transmission dynamics of R. rickettsii. Through a sensitivity analysis, we identified the parameters with significant influence on the R. rickettsii establishment. Afterward, we implemented the Gillespie's algorithm to simulate the impact of potential public health interventions to prevent BSF human cases.The introduction of a single infected capybara with at least one infected attached tick is enough to trigger the disease in a non-endemic area. We found that to avoid the formation of new BSF-endemic areas, it is crucial to impede the emigration of capybaras from endemic areas by reducing their birth rate by more than 58%. Model results were corroborated by ex-situ data generated from field studies, and this supports our proposal to prevent BSF human cases by implementing control strategies focused on capybaras.The proposed stochastic model illustrates how strategies for the control and prevention of vector-borne infectious diseases can be focused on amplifier hosts management practices. This work provides a basis for future prevention strategies for other neglected vector-borne diseases.
Mulder, Nicola J; Adebiyi, Ezekiel; Adebiyi, Marion; Adeyemi, Seun; Ahmed, Azza; Ahmed, Rehab; Akanle, Bola; Alibi, Mohamed; Armstrong, Don L; Aron, Shaun; Ashano, Efejiro; Baichoo, Shakuntala; Benkahla, Alia; Brown, David K; Chimusa, Emile R; Fadlelmola, Faisal M; Falola, Dare; Fatumo, Segun; Ghedira, Kais; Ghouila, Amel; Hazelhurst, Scott; Isewon, Itunuoluwa; Jung, Segun; Kassim, Samar Kamal; Kayondo, Jonathan K; Mbiyavanga, Mamana; Meintjes, Ayton; Mohammed, Somia; Mosaku, Abayomi; Moussa, Ahmed; Muhammd, Mustafa; Mungloo-Dilmohamud, Zahra; Nashiru, Oyekanmi; Odia, Trust; Okafor, Adaobi; Oladipo, Olaleye; Osamor, Victor; Oyelade, Jellili; Sadki, Khalid; Salifu, Samson Pandam; Soyemi, Jumoke; Panji, Sumir; Radouani, Fouzia; Souiai, Oussama; Tastan Bishop, Özlem
Although pockets of bioinformatics excellence have developed in Africa, generally, large-scale genomic data analysis has been limited by the availability of expertise and infrastructure. H3ABioNet, a pan-African bioinformatics network, was established to build capacity specifically to enable H3Africa (Human Heredity and Health in Africa) researchers to analyze their data in Africa. Since the inception of the H3Africa initiative, H3ABioNet's role has evolved in response to changing needs from the consortium and the African bioinformatics community. H3ABioNet set out to develop core bioinformatics infrastructure and capacity for genomics research in various aspects of data collection, transfer, storage, and analysis. Various resources have been developed to address genomic data management and analysis needs of H3Africa researchers and other scientific communities on the continent. NetMap was developed and used to build an accurate picture of network performance within Africa and between Africa and the rest of the world, and Globus Online has been rolled out to facilitate data transfer. A participant recruitment database was developed to monitor participant enrollment, and data is being harmonized through the use of ontologies and controlled vocabularies. The standardized metadata will be integrated to provide a search facility for H3Africa data and biospecimens. Because H3Africa projects are generating large-scale genomic data, facilities for analysis and interpretation are critical. H3ABioNet is implementing several data analysis platforms that provide a large range of bioinformatics tools or workflows, such as Galaxy, the Job Management System, and eBiokits. A set of reproducible, portable, and cloud-scalable pipelines to support the multiple H3Africa data types are also being developed and dockerized to enable execution on multiple computing infrastructures. In addition, new tools have been developed for analysis of the uniquely divergent African data and for
The population problem in Africa is compounded by attitudes and traditions that favor large families. Children give status, and male children are desired to carry on the ancestral line because, dedpite women's dominance in agriculture, traditional education has inculcated male supremacy in African society. Traditional African attitudes equate having many children with male pride, social status, and security. For women, bearing children is in most instances the best and often the only way to achieve some status in their community. Education and modernization have begun to change these attitudes for a few people, particularly in urban settings, yet the desire for large families is deep rooted and remains widespread among African society. Declining infant mortality has had very little impact on fertility. Crude birthrates have changed little in the past 30 years, dropping only from 48 to 46/1000 population. The momentum of population growth is likely to continue as those under the age of 15, now almost half of Africa's population, grow into adults and start to have their own children. Despite the traditional influences on childbearing, powerful forces for change have been at work during the past decade. More and more governments are becoming acutely aware that many national problems are prompted or exacerbated by a rapidly growing population. The interaction between population and development is now well understood, and policy planners in Africa no longer take for granted the notion that development will help check population growth. Many African governments have initiated programs to ensure that more and better trained health personnel are bringing family planning information and services to rural areas, where pronatalist traditions are especially pervasive. 1 model for this approach is in Kenya where family planning services are now offered within the concept of "district focus." National family planning activities will be planned and implemented at the district
Soares, J F; Soares, H S; Barbieri, A M; Labruna, M B
In the laboratory, Amblyomma cajennense (Acari: Ixodidae) (Fabricius) larvae, nymphs and adults were exposed to Rickettsia rickettsii by feeding on needle-inoculated animals, and thereafter reared on uninfected guinea pigs or rabbits. Regardless of the tick stage that acquired the infection, subsequent tick stages were shown to be infected (confirming transstadial and transovarial transmissions) and were able to transmit R. rickettsii to uninfected animals, as demonstrated by serological and molecular analyses. However, the larval, nymphal and adult stages of A. cajennense were shown to be partially refractory to R. rickettsii infection, as in all cases, only part of the ticks became infected by this agent, after being exposed to rickettsemic animals. In addition, less than 50% of the infected engorged females transmitted rickettsiae transovarially, and when they did so, only part of the offspring became infected, indicating that vertical transmission alone is not enough to maintain R. rickettsii in A. cajennense for multiple generations. Finally, the R. rickettsii-infected tick groups had lower reproductive performance than the uninfected control group. Our results indicate that A. cajennense have a low efficiency to maintain R. rickettsii for successive generations, as R. rickettsii-infection rates should decline drastically throughout the successive tick generations. © 2011 The Authors. Medical and Veterinary Entomology © 2011 The Royal Entomological Society.
Kartashov, Mikhail Yu; Glushkova, Ludmila I; Mikryukova, Tamara P; Korabelnikov, Igor V; Egorova, Yulia I; Tupota, Natalia L; Protopopova, Elena V; Konovalova, Svetlana N; Ternovoi, Vladimir A; Loktev, Valery B
The number of tick-borne infections in the northern European regions of Russia has increased considerably in the last years. In the present study, 676 unfed adult Ixodes persulcatus ticks were collected in the Komi Republic from 2011 to 2013 to study tick-borne rickettsioses. Rickettsia spp. DNA was detected by PCR in 51 (7.6%) ticks. The nucleotide sequence analysis of gltA fragments (765bp) from 51 ticks indicated that 60.8% and 39.2% of the ticks were infected with Rickettsia helvetica and Candidatus R. tarasevichiae, respectively. The gltA fragments showed 100% identity with those of Candidatus R. tarasevichiae previously discovered in Siberia and China, whereas R. helvetica showed 99.9% sequence identity with European isolates. The ompB had 8 nucleotide substitutions, 6 of which resulted in amino acid substitutions. In the sca9 gene, 3 nucleotide substitutions were detected, and only one resulted in amino acid substitution. The smpA, ompW, and β-lactamase genes of R. helvetica also showed a high level of sequence identity. Copyright © 2017 Elsevier GmbH. All rights reserved.
Budachetri, K; Kumar, D; Karim, S
The Gulf Coast tick (Amblyomma maculatum) has evolved as a competent vector of the spotted-fever group rickettsia, Rickettsia parkeri. In this study, the functional role of catalase, an enzyme responsible for the degradation of toxic hydrogen peroxide, in the colonization of the tick vector by R. parkeri and transovarial transmission of this pathogen to the next tick generation, was investigated. Catalase gene (CAT) expression in midgut, salivary glands and ovarian tissues exhibited a 2-11-fold increase in transcription level upon R. parkeri infection. Depletion of CAT transcripts using an RNA-interference approach significantly reduced R. parkeri infection levels in midgut and salivary gland tissues by 53-63%. The role of CAT in transovarial transmission of R. parkeri was confirmed by simultaneously blocking the transcript and the enzyme by injecting double-stranded RNA for CAT and a catalase inhibitor (3-amino-1,2,4-triazole) into gravid females. Simultaneous inhibition of the CAT transcript and the enzyme significantly reduced the egg conversion ratio with a 44% reduction of R. parkeri transovarial transmission. These data suggest that catalase is required for rickettsial colonization of the tick vector and transovarial transmission to the next generation. © 2017 The Royal Entomological Society.
Sousa, Rita de; França, Ana; Dória Nòbrega, Sónia; Belo, Adelaide; Amaro, Mario; Abreu, Tiago; Poças, José; Proença, Paula; Vaz, José; Torgal, Jorge; Bacellar, Fátima; Ismail, Nahed; Walker, David H
The pathophysiologic mechanisms that determine the severity of Mediterranean spotted fever (MSF) and the host-related and microbe-related risk factors for a fatal outcome are incompletely understood. This prospective study used univariate and multivariate analyses to determine the risk factors for a fatal outcome for 140 patients with Rickettsia conorii infection admitted to 13 Portuguese hospitals during 1994-2006 with documented identification of the rickettsial strain causing their infection. A total of 71 patients (51%) were infected with the Malish strain of Rickettsia conorii, and 69 (49%) were infected with the Israeli spotted fever (ISF) strain. Patients were admitted to the intensive care unit (40 [29%]), hospitalized as routine inpatients (95[67%]), or managed as outpatients (5[4%]). Death occurred in 29 adults (21%). A fatal outcome was significantly more likely for patients infected with the ISF strain, and alcoholism was a risk factor. The pathophysiology of a fatal outcome involved significantly greater incidence of petechial rash, gastrointestinal symptoms, obtundation and/or confusion, dehydration, tachypnea, hepatomegaly, leukocytosis, coagulopathy, azotemia, hyperbilirubinemia, and elevated levels of hepatic enzymes and creatine kinase. Some, but not all, of these findings were observed more often in ISF strain-infected patients. Although fatalities and similar clinical manifestations occurred among both groups of patients, the ISF strain was more virulent than the Malish strain. Multivariate analysis revealed that acute renal failure and hyperbilirubinemia were most strongly associated with a fatal outcome.
Reed, Shawna C O; Serio, Alisa W; Welch, Matthew D
Rickettsiae are obligate intracellular pathogens that are transmitted to humans by arthropod vectors and cause diseases such as spotted fever and typhus. Although rickettsiae require the host cell actin cytoskeleton for invasion, the cytoskeletal proteins that mediate this process have not been completely described. To identify the host factors important during cell invasion by Rickettsia parkeri, a member of the spotted fever group (SFG), we performed an RNAi screen targeting 105 proteins in Drosophila melanogaster S2R+ cells. The screen identified 21 core proteins important for invasion, including the GTPases Rac1 and Rac2, the WAVE nucleation-promoting factor complex and the Arp2/3 complex. In mammalian cells, including endothelial cells, the natural targets of R. parkeri, the Arp2/3 complex was also crucial for invasion, while requirements for WAVE2 as well as Rho GTPases depended on the particular cell type. We propose that R. parkeri invades S2R+ arthropod cells through a primary pathway leading to actin nucleation, whereas invasion of mammalian endothelial cells occurs via redundant pathways that converge on the host Arp2/3 complex. Our results reveal a key role for the WAVE and Arp2/3 complexes, as well as a higher degree of variation than previously appreciated in actin nucleation pathways activated during Rickettsia invasion. © 2011 Blackwell Publishing Ltd.
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.
Matheus Dias Cordeiro
Full Text Available The aim of this study was to investigate the presence of anti-Rickettsia spp. antibodies, the tick fauna, and the ticks that are carriers of rickettsiae of the spotted fever group (SFG. About 68 (24% of the 283 serum samples tested by indirect immunofluorescence (IFA reacted against the R. rickettsii crude antigen. The titers varied between 1:64 and 1:512. At the time of collection, 189 (64.5% of the 293 dogs included in this study, were infested with ticks. Ticks classified as Rhipicephalus sanguineus and Amblyomma sculptum were identified. None of the ticks examined for SFG rickettsiae using polymerase chain reaction (PCR were positive. The presence of the anti-R. rickettsii antibodies detected by IFA, albeit at low titers, suggests the circulation of SFG rickettsiae, which requires permanent surveillance because there are records on human fatalities related to spotted fever and to avoid any future threats to the students moving extensively in the areas near of the Rural Federal University of Rio de Janeiro.
Morganti, Giulia; Gavaudan, Stefano; Canonico, Cristina; Ravagnan, Silvia; Olivieri, Emanuela; Diaferia, Manuela; Marenzoni, Maria Luisa; Antognoni, Maria Teresa; Capelli, Gioia; Silaghi, Cornelia; Veronesi, Fabrizia
Dogs are a common feeding hosts for Ixodes ricinus and may act as reservoir hosts for zoonotic tick-borne pathogens (TBPs) and as carriers of infected ticks into human settings. The aim of this work was to evaluate the presence of several selected TBPs of significant public health concern by molecular methods in I. ricinus recovered from dogs living in urban and suburban settings in central Italy. A total of 212 I. ricinus specimens were collected from the coat of domestic dogs. DNA was extracted from each specimen individually and tested for Rickettsia spp., Borrelia burgdorferi sensu lato, Babesia spp., and Anaplasma phagocytophilum, using real-time and conventional PCR protocols, followed by sequencing. Sixty-one ticks (28.8%) tested positive for TBPs; 57 samples were infected by one pathogen, while four showed coinfections. Rickettsia spp. was detected in 39 specimens (18.4%), of which 32 were identified as Rickettsia monacensis and seven as Rickettsia helvetica. Twenty-two samples (10.4%) tested positive for A. phagocytophilum; Borrelia lusitaniae and Borrelia afzelii were detected in two specimens and one specimen, respectively. One tick (0.5%) was found to be positive for Babesia venatorum (EU1). Our findings reveal the significant exposure of dogs to TBPs of public health concern and provide data on the role of dogs in the circulation of I. ricinus-borne pathogens in central Italy.
Nugnes, Francesco; Gebiola, Marco; Monti, Maurilia Maria; Gualtieri, Liberata; Giorgini, Massimo; Wang, Jianguo; Bernardo, Umberto
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
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.
English in Africa was founded in 1974 to provide a forum for the study of African literature and English as a language of Africa. The Editor invites contributions, including unsolicited reviews, on all aspects of English writing and the English language in Africa, including oral traditions. English in Africa is listed in the Journal of ...
Juan Carlos Quintero
Full Text Available Introducción. Las rickettsias son bacterias patógenas usualmente transmitidas por ectoparásitos, como garrapatas, piojos o pulgas. En la última década se presentaron tres brotes de rickettsiosis con casos fatales en la región noroccidental de Antioquia y en un municipio limítrofe de Córdoba. Objetivo. Describir la ecología y la epidemiología de las infecciones por Rickettsia spp. en el Urabá antioqueño. Materiales y métodos. Se obtuvieron muestras de 354 roedores y se recolectaron 839 ectoparásitos de estos en los municipios de Apartadó, Turbo y Necoclí. Asimismo, se obtuvieron 220 sueros humanos. Estas muestras fueron estudiadas por reacción en cadena de la polimerasa (PCR e inmunofluorescencia indirecta (IFI para la detección de infección por rickettsias. Resultados. Por IFI se detectaron anticuerpos antirickettsias en 130 (43 % de los roedores y en 53 (24% de los sueros humanos estudiados. Además, se amplificaron secuencias del gen gltA específicas del género Rickettsia en 23 (6,8 % muestras de hígado de roedores, las cuales mostraron una similitud del 98,7 % con R. prowazekii. Una secuencia de gltA obtenida de larvas de garrapatas del género Amblyomma sp., tuvo una identidad mayor de 99 % con las secuencias de R. tamurae. Conclusión. Estos resultados demuestran la circulación de rickettsias en roedores, ectoparásitos y humanos en los municipios estudiados. doi: http://dx.doi.org/10.7705/biomedica.v33i0.735
DeLong, Edward F
The complete genome sequence of Thermoplasma acidophilum, an acid- and heat-loving archaeon, has recently been reported. Comparative genomic analysis of this 'extremophile' is providing new insights into the metabolic machinery, ecology and evolution of thermophilic archaea.
Bennetzen, Jeffrey L.; SanMiguel, Phillip; Chen, Mingsheng; Tikhonov, Alexander; Francki, Michael; Avramova, Zoya
For the most part, studies of grass genome structure have been limited to the generation of whole-genome genetic maps or the fine structure and sequence analysis of single genes or gene clusters. We have investigated large contiguous segments of the genomes of maize, sorghum, and rice, primarily focusing on intergenic spaces. Our data indicate that much (>50%) of the maize genome is composed of interspersed repetitive DNAs, primarily nested retrotransposons that in...
Jun, Se-Ran; Leuze, Michael R.; Nookaew, Intawat; Uberbacher, Edward C.; Land, Miriam; Zhang, Qian; Wanchai, Visanu; Chai, Juanjuan; Nielsen, Morten; Trolle, Thomas; Lund, Ole; Buzard, Gregory S.; Pedersen, Thomas D.; Wassenaar, Trudy M.; Ussery, David W.
The 2014 Ebola outbreak in West Africa is the largest documented for this virus. To examine the dynamics of this genome, we compare more than 100 currently available ebolavirus genomes to each other and to other viral genomes. Based on oligomer frequency analysis, the family Filoviridae forms a distinct group from all other sequenced viral genomes. All filovirus genomes sequenced to date encode proteins with similar functions and gene order, although there is considerable divergence in sequences between the three genera Ebolavirus, Cuevavirus and Marburgvirus within the family Filoviridae. Whereas all ebolavirus genomes are quite similar (multiple sequences of the same strain are often identical), variation is most common in the intergenic regions and within specific areas of the genes encoding the glycoprotein (GP), nucleoprotein (NP) and polymerase (L). We predict regions that could contain epitope-binding sites, which might be good vaccine targets. This information, combined with glycosylation sites and experimentally determined epitopes, can identify the most promising regions for the development of therapeutic strategies. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). PMID:26175035
Norrild, Bodil; Guldberg, Per; Ralfkiær, Elisabeth Methner
Almost all cells in the human body contain a complete copy of the genome with an estimated number of 25,000 genes. The sequences of these genes make up about three percent of the genome and comprise the inherited set of genetic information. The genome also contains information that determines whe...
Andoh, Masako; Sakata, Akiko; Takano, Ai; Kawabata, Hiroki; Fujita, Hiromi; Une, Yumi; Goka, Koichi; Kishimoto, Toshio; Ando, Shuji
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
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
Romer, Yamila; Nava, Santiago; Govedic, Francisco; Cicuttin, Gabriel; Denison, Amy M.; Singleton, Joseph; Kelly, Aubree J.; Kato, Cecilia Y.; Paddock, Christopher D.
Rickettsia parkeri, a newly recognized tick-borne pathogen of humans in the Americas, is a confirmed cause of spotted fever group rickettsiosis in Argentina. Until recently, almost all cases of R. parkeri rickettsiosis in Argentina have originated from the Paraná River Delta, where entomological surveys have identified populations of R. parkeri-infected Amblyomma triste ticks. In this report, we describe confirmed cases of R. parkeri rickettsiosis from Córdoba and La Rioja provinces, which are located several hundred kilometers inland, and in a more arid ecological region, where A. triste ticks do not occur. Additionally, we identified questing A. tigrinum ticks naturally infected with R. parkeri in Córdoba province. These data provide evidence that another human-biting tick species serves as a potential vector of R. parkeri in Argentina and possibly, other countries of South America. PMID:25349376
Noden, Bruce H; Martin, Jaclyn; Carrillo, Yisel; Talley, Justin L; Ochoa-Corona, Francisco M
The importance of tick and flea-borne rickettsia infections is increasingly recognized worldwide. While increased focus has shifted in recent years to the development of point-of-care diagnostics for various vector-borne diseases in humans and animals, little research effort has been devoted to their integration into vector surveillance and control programs, particularly in resource-challenged countries. One technology which may be helpful for large scale vector surveillance initiatives is loop-mediated isothermal amplification (LAMP). The aim of this study was to develop a LAMP assay to detect spotted fever group (SFG) rickettsia DNA from field-collected ticks and fleas and compare with published end-point PCR results. A Spotted Fever Group rickettsia-specific loop-mediated isothermal amplification (SFGR-LAMP) assay was developed using primers based on a region of the R. rickettsii 17kDa protein gene. The sensitivity, specificity, and reproducibility of the assay were evaluated. The assay was then compared with the results of end-point PCR assays for pooled tick and flea samples obtained from field-based surveillance studies. The sensitivity of the SFGR-LAMP assay was 0.00001 ng/μl (25μl volume) which was 10 times more sensitive than the 17kDa protein gene end-point PCR used as the reference method. The assay only recognized gDNA from SFG and transitional group (TRG) rickettsia species tested but did not detect gDNA from typhus group (TG) rickettsia species or closely or distantly related bacterial species. The SFGR-LAMP assay detected the same positives from a set of pooled tick and flea samples detected by end-point PCR in addition to two pooled flea samples not detected by end-point PCR. To our knowledge, this is the first study to develop a functional LAMP assay to initially screen for SFG and TRG rickettsia pathogens in field-collected ticks and fleas. With a high sensitivity and specificity, the results indicate the potential use as a field
Maria Fernanda B M Galletti
Full Text Available Rickettsia rickettsii is an obligate intracellular tick-borne bacterium that causes Rocky Mountain Spotted Fever (RMSF, the most lethal spotted fever rickettsiosis. When an infected starving tick begins blood feeding from a vertebrate host, R. rickettsii is exposed to a temperature elevation and to components in the blood meal. These two environmental stimuli have been previously associated with the reactivation of rickettsial virulence in ticks, but the factors responsible for this phenotype conversion have not been completely elucidated. Using customized oligonucleotide microarrays and high-throughput microfluidic qRT-PCR, we analyzed the effects of a 10°C temperature elevation and of a blood meal on the transcriptional profile of R. rickettsii infecting the tick Amblyomma aureolatum. This is the first study of the transcriptome of a bacterium in the genus Rickettsia infecting a natural tick vector. Although both stimuli significantly increased bacterial load, blood feeding had a greater effect, modulating five-fold more genes than the temperature upshift. Certain components of the Type IV Secretion System (T4SS were up-regulated by blood feeding. This suggests that this important bacterial transport system may be utilized to secrete effectors during the tick vector's blood meal. Blood feeding also up-regulated the expression of antioxidant enzymes, which might correspond to an attempt by R. rickettsii to protect itself against the deleterious effects of free radicals produced by fed ticks. The modulated genes identified in this study, including those encoding hypothetical proteins, require further functional analysis and may have potential as future targets for vaccine development.
The article gives information on contracts announced (and to whom) in some parts of Africa in the petroleum, natural gas and petrochemicals industries. Countries specifically mentioned are Algeria, Angola, Nigeria, South Africa and Tunisia
Goldwyn, David L
.... Africa's importance to U.S. energy security is rising due to Africa's expanding role as an incremental supplier of oil in a tight global oil market, its relative openness to foreign investment, increasing levels of U.S...
Delmas, Olivier; Holmes, Edward C.; Talbi, Chiraz; Larrous, Florence; Dacheux, Laurent; Bouchier, Christiane; Bourhy, Hervé
Lyssaviruses are RNA viruses with single-strand, negative-sense genomes responsible for rabies-like diseases in mammals. To date, genomic and evolutionary studies have most often utilized partial genome sequences, particularly of the nucleoprotein and glycoprotein genes, with little consideration of genome-scale evolution. Herein, we report the first genomic and evolutionary analysis using complete genome sequences of all recognised lyssavirus genotypes, including 14 new complete genomes of field isolates from 6 genotypes and one genotype that is completely sequenced for the first time. In doing so we significantly increase the extent of genome sequence data available for these important viruses. Our analysis of these genome sequence data reveals that all lyssaviruses have the same genomic organization. A phylogenetic analysis reveals strong geographical structuring, with the greatest genetic diversity in Africa, and an independent origin for the two known genotypes that infect European bats. We also suggest that multiple genotypes may exist within the diversity of viruses currently classified as ‘Lagos Bat’. In sum, we show that rigorous phylogenetic techniques based on full length genome sequence provide the best discriminatory power for genotype classification within the lyssaviruses. PMID:18446239
Full Text Available Lyssaviruses are RNA viruses with single-strand, negative-sense genomes responsible for rabies-like diseases in mammals. To date, genomic and evolutionary studies have most often utilized partial genome sequences, particularly of the nucleoprotein and glycoprotein genes, with little consideration of genome-scale evolution. Herein, we report the first genomic and evolutionary analysis using complete genome sequences of all recognised lyssavirus genotypes, including 14 new complete genomes of field isolates from 6 genotypes and one genotype that is completely sequenced for the first time. In doing so we significantly increase the extent of genome sequence data available for these important viruses. Our analysis of these genome sequence data reveals that all lyssaviruses have the same genomic organization. A phylogenetic analysis reveals strong geographical structuring, with the greatest genetic diversity in Africa, and an independent origin for the two known genotypes that infect European bats. We also suggest that multiple genotypes may exist within the diversity of viruses currently classified as 'Lagos Bat'. In sum, we show that rigorous phylogenetic techniques based on full length genome sequence provide the best discriminatory power for genotype classification within the lyssaviruses.
Genotyping breeding materials is now relatively inexpensive but phenotyping costs have remained the same. One method to increase gene mapping power is to use genome-wide genetic markers to combine existing phenotype data for multiple populations into a unified analysis. We combined data from 15 bipa...
Wisse, J.A.; Stigter, C.J.
The International Association for Wind Engineering (IAWE) has very few contacts in Africa, the second-largest continent. This paper reviews important wind-related African issues. They all require data on wind climate, which are very sparse in Africa. Wind engineering in Africa can assist in
Author Guidelines. Africa Insight is a quarterly, peer-reviewed journal of the Africa Institute of South Africa (AISA). It is accredited by the Department of Higher ... Abstract: All articles should be accompanied by an abstract of between 100 and 125 words stating the main research problem, major findings and conclusion(s).
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
Roberta Santos Toledo
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
ElHefnawi, Mahmoud; Jeon, Sungwon; Bhak, Youngjune; ElFiky, Asmaa; Horaiz, Ahmed; Jun, JeHoon; Kim, Hyunho; Bhak, Jong
We report two Egyptian male genomes (EGP1 and EGP2) sequenced at ~ 30× sequencing depths. EGP1 had 4.7 million variants, where 198,877 were novel variants while EGP2 had 209,109 novel variants out of 4.8 million variants. The mitochondrial haplogroup of the two individuals were identified to be H7b1 and L2a1c, respectively. We also identified the Y haplogroup of EGP1 (R1b) and EGP2 (J1a2a1a2 > P58 > FGC11). EGP1 had a mutation in the NADH gene of the mitochondrial genome ND4 (m.11778 G > A) that causes Leber's hereditary optic neuropathy. Some SNPs shared by the two genomes were associated with an increased level of cholesterol and triglycerides, probably related with Egyptians obesity. Comparison of these genomes with African and Western-Asian genomes can provide insights on Egyptian ancestry and genetic history. This resource can be used to further understand genomic diversity and functional classification of variants as well as human migration and evolution across Africa and Western-Asia. Copyright © 2017. Published by Elsevier B.V.
Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop in the tropics. Genomic selection (GS) has been implemented at three breeding institutions in Africa in order to reduce cycle times. Initial studies provided promising estimates of predictive abilities. Here, we expand on p...
Reimerink Johan R
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.
Biernat, Beata; Stańczak, Joanna; Michalik, Jerzy; Sikora, Bożena; Wierzbicka, Anna
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. Copyright © 2015 Elsevier GmbH. All rights reserved.
Billeter, Sarah A; Diniz, Pedro Paulo Vissotto de Paiva; Jett, Lindsey A; Wournell, Andrea L; Kjemtrup, Anne M; Padgett, Kerry A; Yoshimizu, Melissa Hardstone; Metzger, Marco E; Barr, Margaret C
Rickettsia typhi, transmitted by rat fleas, causes most human flea-borne rickettsioses worldwide. Another rickettsia, Rickettsia felis, found in cat fleas, Ctenocephalides felis, has also been implicated as a potential human pathogen. In the continental United States, human cases of flea-borne rickettsioses are reported primarily from the southern regions of Texas and California where the cat flea is considered the principal vector. In California, more than 90% of locally acquired human cases are reported from suburban communities within Los Angeles and Orange counties despite the almost ubiquitous presence of cat fleas and their hosts throughout the state. The objective of this study is to assess the presence and infection rate of Rickettsia species in cat fleas from selected endemic and nonendemic regions of California. Cat fleas were collected from cats in Los Angeles County (endemic region) and Sacramento and Contra Costa counties (nonendemic region). Sequencing of 17 amplicons confirmed the presence of R. felis in both the endemic and non-endemic regions with a calculated maximum likelihood estimation of 131 and 234 per 1000 fleas, respectively. R. typhi was not detected in any flea pools. Two R. felis-like genotypes were also detected in fleas from Los Angeles County; Genotype 1 was detected in 1 flea pool and Genotype 2 was found in 10 flea pools. Genotype 1 was also detected in a single flea pool from Sacramento County. Results from this study show that R. felis is widespread in cat flea populations in both flea-borne rickettsioses endemic and nonendemic regions of California, suggesting that a high prevalence of this bacterium in cat fleas does not predispose to increased risk of human infection. Further studies are needed to elucidate the role of R. felis and the two R. felis-like organisms as etiologic agents of human flea-borne rickettsioses in California.
In this paper, the author presents the theory that for Africa to work towards reduction of global warming, it must first address its environmental problems; i.e. land use, deforestation, desertification, poverty and hunger. He argues that Africa should aim for growth in the productivity and quantity of energy use. The following suggestions were made: Africa must shift from low-quantity biomass to secondary sources in the short term; developed countries must avoid pushing experimental and frontier technologies on Africa; with financial and technical help, Africa could develop its largely untapped reserves of hydropower. Nuclear power should not be an option because reliable production is not possible at present
EREMEEVA, MARINA E.; KARPATHY, SANDOR E.; KRUEGER, LAURA; HAYES, ERICA K.; WILLIAMS, ASHLEY M.; ZALDIVAR, YAMITZEL; BENNETT, STEPHEN; CUMMINGS, ROBERT; TILZER, ART; VELTEN, ROBERT K.; KERR, NELSON; DASCH, GREGORY A.; HU, RENJIE
Results of an environmental assessment conducted in a newly emergent focus of murine typhus in southern California are described. Opossums, Didelphis virginiana Kerr, infested with cat fleas, Ctenocephalides felis Buché, in the suburban area were abundant. Animal and flea specimens were tested for the DNA of two flea-borne rickettsiae, Rickettsia typhi and Rickettsia felis. R. felis was commonly detected in fleas collected throughout this area while R. typhi was found at a much lower prevalence in the vicinity of just 7 of 14 case-patient homes identified. DNA of R. felis, but not R. typhi, was detected in renal, hepatic, and pulmonary tissues of opossums. In contrast, there were no hematologic polymerase chain reaction findings of R. felis or R. typhi in opossums, rats, and cats within the endemic area studied. Our data suggest a significant probability of human exposure to R. felis in the area studied; however, disease caused by this agent is not recognized by the medical community and may be misdiagnosed as murine typhus using nondiscriminatory serologic methods. PMID:23270180
Cai, J.; Winkler, H.H.
The regulation of the citrate synthase (gltA) and ATP/ADP translocase (tlc) genes of the obligate intracellular bacterium, Rickettsia prowazekii, was analyzed in rickettsia-infected respiration-deficient G14 cells. The level of the gltA mRNAII and the tlc mRNA was much lower in the total RNA isolated from the infected G 14 cells grown in 1 g/1 glucose (low glucose, GL) medium than in that from infected G 14 cells grown in 4.5 g/l glucose (high glucose, GH) medium. However, the level of the gltA mRNAI relative to 16 S rRNA was the same in GL and GH media. An increase in the level of the gltA mRNAII and the tlc mRNA could be observed as early as 2 hrs after shifting from GL to GH medium. We conclude that, under these experimental conditions, the tlc promoter and the gltA promoter P2, but not gltA promoter P1, were transcriptionally regulated. Key words: Rickettsia prowazekii; gltA gene; tlC gene; transcriptional regulation; G 14 cells (authors)
Energy and economic growth are connected and the wealth of Western countries is based on a high availability of energy. Africa is a continent vast by its size, well populated and well supplied with fossil energy (oil, gas, coal) and renewable energy (hydroelectric, biomass, solar). But consumption is limited, without distribution infrastructures and initially, without capitals for necessary investments. The situation is particularly critical in Sub-Sahara Africa since the African energy consumption is mainly concentrated in South Africa and North Africa. An annual conference, the Energy Summit in Africa, brings together all players in the sector, from all the continent's countries, from Europe and America, in an attempt to establish recommendations for more availability and a better use of energy in Africa. The next summit is scheduled for November 23 to 25, 2004 in Dakar. The program relies on the Association for the Development of Energy in Africa, which will be created shortly. (author)
the cell nucleus (mitochondrial and chloroplast genomes), and. (3) traits governed ... tively good embryonic development but very poor development of membranes and ... Human homologies for the type of situation described above are naturally ..... imprint; (b) New modifications of the paternal genome in germ cells of each ...
Oers, van M.M.; Vlak, J.M.
Baculovirus genomes are covalently closed circles of double stranded-DNA varying in size between 80 and 180 kilobase-pair. The genomes of more than fourty-one baculoviruses have been sequenced to date. The majority of these (37) are pathogenic to lepidopteran hosts; three infect sawflies
... this database. Top of Page Evaluation of Genomic Applications in Practice and Prevention (EGAPP™) In 2004, the Centers for Disease Control and Prevention launched the EGAPP initiative to establish and test a ... and other applications of genomic technology that are in transition from ...
Hoelzel, A Rus
Ever since its invention, the polymerase chain reaction has been the method of choice for work with ancient DNA. In an application of modern genomic methods to material from the Pleistocene, a recent study has instead undertaken to clone and sequence a portion of the ancient genome of the cave bear.
Dippenaar, Anzaan; Parsons, Sven David Charles; Sampson, Samantha Leigh; Van Der Merwe, Ruben Gerhard; Drewe, Julian Ashley; Abdallah, Abdallah; Siame, Kabengele Keith; Gey Van Pittius, Nicolaas Claudius; Van Helden, Paul David; Pain, Arnab; Warren, Robin Mark
Tuberculosis occurs in various mammalian hosts and is caused by a range of different lineages of the Mycobacterium tuberculosis complex (MTBC). A recently described member, Mycobacterium suricattae, causes tuberculosis in meerkats (Suricata suricatta) in Southern Africa and preliminary genetic analysis showed this organism to be closely related to an MTBC pathogen of rock hyraxes (Procavia capensis), the dassie bacillus. Here we make use of whole genome sequencing to describe the evolution of the genome of M. suricattae, including known and novel regions of difference, SNPs and IS6110 insertion sites. We used genome-wide phylogenetic analysis to show that M. suricattae clusters with the chimpanzee bacillus, previously isolated from a chimpanzee (Pan troglodytes) in West Africa. We propose an evolutionary scenario for the Mycobacterium africanum lineage 6 complex, showing the evolutionary relationship of M. africanum and chimpanzee bacillus, and the closely related members M. suricattae, dassie bacillus and Mycobacterium mungi.
Tuberculosis occurs in various mammalian hosts and is caused by a range of different lineages of the Mycobacterium tuberculosis complex (MTBC). A recently described member, Mycobacterium suricattae, causes tuberculosis in meerkats (Suricata suricatta) in Southern Africa and preliminary genetic analysis showed this organism to be closely related to an MTBC pathogen of rock hyraxes (Procavia capensis), the dassie bacillus. Here we make use of whole genome sequencing to describe the evolution of the genome of M. suricattae, including known and novel regions of difference, SNPs and IS6110 insertion sites. We used genome-wide phylogenetic analysis to show that M. suricattae clusters with the chimpanzee bacillus, previously isolated from a chimpanzee (Pan troglodytes) in West Africa. We propose an evolutionary scenario for the Mycobacterium africanum lineage 6 complex, showing the evolutionary relationship of M. africanum and chimpanzee bacillus, and the closely related members M. suricattae, dassie bacillus and Mycobacterium mungi.
Full Text Available Introducción: La vigilancia de las enfermedades transmitidas por vectores es importante para establecer medidas de control en salud pública. Las poblaciones indígenas de Córdoba viven en condiciones geoclimáticas que favorecen la presencia de vectores que podrían permitir la diseminación y aparición de hantavirosis, rickettsiosis y fiebre por el virus Chikungunya. Objetivo: Establecer la seroprevalencia de Hantavirus, Rickettsia sp. y Chikungunya en la población indígena de Tuchín, Córdoba. Materiales y métodos: Se realizó un estudio descriptivo de corte transversal en 190 individuos del resguardo indígena del municipio de Tuchín; el muestreo fue realizado entre agosto y diciembre del 2012. La detección de anticuerpos IgG contra Hantavirus se llevó a cabo con la prueba IgG DxSelectTM (Focus Technologies, EL1600G, California, EE. UU., anticuerpos IgG contra Rickettsia sp. se determinaron por inmunofluorescencia indirecta y se realizó detección de anticuerpos IgG contra el virus Chikungunya mediante ELISA de captura (Nova-Tec, inmunodiagnostica GmbH, CHIG0590, Alemania. Resultados: De 190 sueros analizados, el 5,2% (10/190 fueron positivos para Rickettsia sp. del grupo de la fiebre manchada, para Hantavirus 7 de 87 (8% fueron positivos y no se encontraron positivos para Chikungunya. No se encontraron diferencias significativas (p = 0,05 entre los seropositivos de Hantavirus y Rickettsia sp. para las variables género, edad y ocupación. Conclusiones: Los hallazgos demuestran exposición previa a Rickettsia sp. y a Hantavirus en la población indígena de Tuchín. Los resultados pueden ser útiles para establecer una alerta sobre estas fiebres hemorrágicas. Aunque no se hallaron seropositivos para Chikungunya, este fue el primer trabajo de vigilancia epidemiológica realizado en Colombia sobre este virus.
Dandara, Collet; Huzair, Farah; Borda-Rodriguez, Alexander; Chirikure, Shadreck; Okpechi, Ikechi; Warnich, Louise; Masimirembwa, Collen
Interest in genomics research in African populations is experiencing exponential growth. This enthusiasm stems in part from the recognition that the genomic diversity of African populations is a window of opportunity for innovations in postgenomics medicine, ecology, and evolutionary biology. The recently launched H3Africa initiative, for example, captures the energy and momentum of this interest. This interdisciplinary socio-technical analysis highlights the challenges that have beset previous genomics research activities in Africa, and looking ahead, suggests constructive ways H3Africa and similar large scale science efforts could usefully chart a new era of genomics and life sciences research in Africa that is locally productive and globally competitive. As independent African scholars and social scientists, we propose that any serious global omics science effort, including H3Africa, aiming to build genomics research capacity and capability in Africa, needs to fund the establishment of biobanks and the genomic analyses platforms within Africa. Equally they need to prioritize community engagement and bioinformatics capability and the training of African scientists on these platforms. Historically, the financial, technological, and skills imbalance between Africa and developed countries has created exploitative frameworks of collaboration where African researchers have become merely facilitators of Western funded and conceived research agendas involving offshore expatriation of samples. Not surprisingly, very little funding was allocated to infrastructure and human capital development in the past. Moving forward, capacity building should materialize throughout the entire knowledge co-production trajectory: idea generation (e.g., brainstorming workshops for innovative hypotheses development by African scientists), data generation (e.g., genome sequencing), and high-throughput data analysis and contextualization. Additionally, building skills for political science
Choi, Jae Young; Bubnell, Jaclyn E.; Aquadro, Charles F.
Coevolution between Drosophila and its endosymbiont Wolbachia pipientis has many intriguing aspects. For example, Drosophila ananassae hosts two forms of W. pipientis genomes: One being the infectious bacterial genome and the other integrated into the host nuclear genome. Here, we characterize the infectious and integrated genomes of W. pipientis infecting D. ananassae (wAna), by genome sequencing 15 strains of D. ananassae that have either the infectious or integrated wAna genomes. Results indicate evolutionarily stable maternal transmission for the infectious wAna genome suggesting a relatively long-term coevolution with its host. In contrast, the integrated wAna genome showed pseudogene-like characteristics accumulating many variants that are predicted to have deleterious effects if present in an infectious bacterial genome. Phylogenomic analysis of sequence variation together with genotyping by polymerase chain reaction of large structural variations indicated several wAna variants among the eight infectious wAna genomes. In contrast, only a single wAna variant was found among the seven integrated wAna genomes examined in lines from Africa, south Asia, and south Pacific islands suggesting that the integration occurred once from a single infectious wAna genome and then spread geographically. Further analysis revealed that for all D. ananassae we examined with the integrated wAna genomes, the majority of the integrated wAna genomic regions is represented in at least two copies suggesting a double integration or single integration followed by an integrated genome duplication. The possible evolutionary mechanism underlying the widespread geographical presence of the duplicate integration of the wAna genome is an intriguing question remaining to be answered. PMID:26254486
Caroline S. Oliveira
Full Text Available RESUMO: A Febre Maculosa Brasileira (FMB é uma doença infecciosa, transmitida por carrapatos ao homem. Uma nova riquetsiose humana foi descrita como causadora de Febre Maculosa no Estado de São Paulo, sendo denominada de Rickettsia sp. cepa Mata Atlântica. O presente trabalho teve como objetivo detectar e identificar proteínas com potencial de estimular o sistema imune de hospedeiro mamífero, desta nova cepa descrita. Para tanto, foi realizado a extração proteica total de Rickettsia sp. cepa Mata Atlântica. As proteínas extraídas foram fracionadas por eletroforese. As bandas proteicas foram transferidas para membranas de nitrocelulose por migração elétrica e submetidas à técnica de Western-blot, para detecção proteica. Ao todo sete proteínas imunorreativas foram detectadas. Duas proteínas apresentaram maior abundancia, com peso molecular, de 200 e 130 kDa respectivamente. Através da comparação de mapas proteômicos existentes e pelo peso molecular que estas proteínas apresentaram, sugere-se que as duas proteínas detectadas representem rOmpA (200 kDa e rOmpB (130 kDa. As demais proteínas detectadas apresentaram menor ocorrência e peso molecular inferior a 78 kDa, podendo representar membros da família de antígenos de superfície celular (Sca - Surface cell antigen. As proteínas detectadas poderão servir como base de estudo na elaboração de métodos diagnósticos sensíveis e específicos, no desenvolvimento de vacinas, além de possibilitarem novos estudos para terapias mais eficazes.
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
Schorn, Sabine; Pfister, Kurt; Reulen, Holger; Mahling, Monia; Silaghi, Cornelia
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. 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. 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 areas are likely to remain in the research focus on
Serosurvey of antibodies against spotted fever group Rickettsia spp. in horse farms in Northern Paraná, Brazil Soroprevalência de anticorpos contra Rickettsia spp. do grupo febre maculosa em equinos de haras no Norte do Paraná, Brasil
Full Text Available Brazilian spotted fever (BSF is an emerging disease most likely caused by Rickettsia rickettsii. The objective of the present study was to estimate the seroprevalence of BSF rickettsia infections in equines from six horse farms located in Londrina County, Paraná, Southern Brazil. Six owners of horse farms situated in Cambé, Santa Fé, Guaraci and Londrina municipalities participated in the study. All farms were located in areas where BSF has not been reported. A total of 273 horses were sampled and their sera were tested by indirect Immunofluorescence assay (IFA using R. rickettsii and R. parkeri antigens. Titers equal to and greater than 64 were considered positive. Of 273 sera tested, 15 (5.5% reacted to R. rickettsii and 5 (1.8% to R. parkeri. Five out of the six farms studied revealed seropositive animals and seropositivity rate ranged from 0 to 13%. The titers ranged from 64 to 512, and four samples had a titer of 512. Nine animals reacted to R. rickettsii with titers four-fold higher than those for R. parkeri. These results suggest that horses in Northern Paraná may have been exposed to rickettsiae identical or closely related to R. rickettsii.Febre Maculosa Brasileira (FMB é uma doença emergente, sendo Rickettsia rickettsii o seu principal agente etiológico. O objetivo deste estudo foi determinar a soroprevalência de rickettsia do grupo da febre maculosa em equinos de seis haras localizados nos municípios de Cambé, Santa Fé, Guaraci e Londrina. As propriedades eram localizadas na região Norte do Paraná onde casos de FMB ainda não foram diagnosticados. Foram colhidas amostras de sangue de 273 equinos, e os soros foram testados pela RIFI, usando R. rickettsii e R. parkeri como antígenos, considerando-se como positivos títulos >64. Entre 273 soros, 15 (5,5% reagiram contra R. rickettsii e 5 (1,8% para R. parkeri. Cinco de seis haras estudados tinham animais reativos, e a taxa de sororreatividade variou de 0 a 13%. Os t
Bakker, Freek T.; Lei, Di; Yu, Jiaying
Herbarium genomics is proving promising as next-generation sequencing approaches are well suited to deal with the usually fragmented nature of archival DNA. We show that routine assembly of partial plastome sequences from herbarium specimens is feasible, from total DNA extracts and with specimens...... up to 146 years old. We use genome skimming and an automated assembly pipeline, Iterative Organelle Genome Assembly, that assembles paired-end reads into a series of candidate assemblies, the best one of which is selected based on likelihood estimation. We used 93 specimens from 12 different...... correlation between plastome coverage and nuclear genome size (C value) in our samples, but the range of C values included is limited. Finally, we conclude that routine plastome sequencing from herbarium specimens is feasible and cost-effective (compared with Sanger sequencing or plastome...
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.
McCown, Michael; Grzeszak, Benjamin
A recent zoonotic and infectious disease field surveillance study in Honduras resulted in the discovery of Toxoplasma, Trypanosoma, Leishmania, Rickettsia, and Lyme disease with statistically high prevalence rates in a group of feral cats. All five diseases--Toxoplasmosis, Trypanosomiasis, Leishmaniasis, Rickettsiosis, and Lyme disease--were confirmed in this group of cats having close contact to local civilians and U.S. personnel. These diseases are infectious to other animals and are known to infect humans as well. In the austere Central and South American sites that Special Operations Forces (SOF) medics are deployed, the living conditions and close quarters are prime environments for the potential spread of infectious and zoonotic disease. This study?s findings, as with previous veterinary disease surveillance studies, emphasize the critical need for continual and aggressive surveillance for zoonotic and infectious disease present within animals in specific areas of operation (AO). The importance to SOF is that a variety of animals may be sentinels, hosts, or direct transmitters of disease to civilians and service members. These studies are value-added tools to the U.S. military, specifically to a deploying or already deployed unit. The SOF medic must ensure that this value-added asset is utilized and that the findings are applied to assure Operational Detachment-Alpha (SFOD-A) health and, on a bigger scale, U.S. military force health protection and local civilian health. © 2010.
Full Text Available Abstract Background The Order Rickettsiales includes important tick-borne pathogens, from Rickettsia rickettsii, which causes Rocky Mountain spotted fever, to Anaplasma marginale, the most prevalent vector-borne pathogen of cattle. Although most pathogens in this Order are transmitted by arthropod vectors, little is known about the microbial determinants of transmission. A. marginale provides unique tools for studying the determinants of transmission, with multiple strain sequences available that display distinct and reproducible transmission phenotypes. The closed core A. marginale genome suggests that any phenotypic differences are due to single nucleotide polymorphisms (SNPs. We combined DNA/RNA comparative genomic approaches using strains with different tick transmission phenotypes and identified genes that segregate with transmissibility. Results Comparison of seven strains with different transmission phenotypes generated a list of SNPs affecting 18 genes and nine promoters. Transcriptional analysis found two candidate genes downstream from promoter SNPs that were differentially transcribed. To corroborate the comparative genomics approach we used three RNA-seq platforms to analyze the transcriptomes from two A. marginale strains with different transmission phenotypes. RNA-seq analysis confirmed the comparative genomics data and found 10 additional genes whose transcription between strains with distinct transmission efficiencies was significantly different. Six regions of the genome that contained no annotation were found to be transcriptionally active, and two of these newly identified transcripts were differentially transcribed. Conclusions This approach identified 30 genes and two novel transcripts potentially involved in tick transmission. We describe the transcriptome of an obligate intracellular bacterium in depth, while employing massive parallel sequencing to dissect an important trait in bacterial pathogenesis.
.... This report from Sub-Saharan Africa, Benin, Botswana, Burkina, Cameroon, Chad, Comoros, Ethiopia, Ghana, Guinea, Kenya, Liberia, Madagascar, Mauritius, Mozambique, Sierra Leone, Somalia, South Africa...
.... This report on Sub-Saharan Africa, Angola, Botswana, Burkina, Cameroon, Ghana, Ivory Coast, Liberia, Madagascar, Malawi, Mali, Mozambique, Namibia, Senegal, South Africa, and Swaziland, contains...
.... This report from Sub-Saharan Africa, Angola, Benin, Botswana, Burundi, Ghana, Lesoto, Liberia, Malawi, Namibia, Nigeria, Senegal, Seychelles, South Africa, Tanzania and Zimbabwe, contains articles...
.... This report contains articles from Sub-Saharan Africa, Angola, Ethiopia, Ghana, Mozambique, Namibia, Sierra Leone, Togo, Zambia, and South Africa, the articles deal mainly with Politics, Sociology...
.... This report from Sub-Sahara Africa, Angola, Cameroon, Equatorial Guinea, Ethiopia, Gambia, Kenya, Malawi, Namibia, Mozambique, Niger, Nigeria, Senegal, Sierra Leone, South Africa, Tanzania, Uganda...
You, Danzhen; Hug, Lucia; Anthony, David
Until relatively recently, much of Africa has been among the economically least developed and least densely populated places on earth, replete with villages and rural communities. Africa is changing rapidly, in its economy, trade and investment; in climate change; in conflict and stability; in urbanization, migration patterns, and most of all in…
Emmanuel, Nikolas G.
behind African participation in United Nations (UN) peacekeeping operations in Africa. In doing so, this research focuses on US military aid and foreign troop training from 2002 to 2012, and its impact on African deployments into UN peacekeeping missions in Africa. As can be expected, such third...
In a world that is developing fast, Africa¿s relative stagnation is a human tragedy that challenges the development profession. Although climate and geography, and their effect on local institutions, are not in Africa¿s favour, inappropriate policies (including neglect of agriculture) and weak
Beck, T.H.L.; Cull, R.; Berger, A.; Molyneux, P.; Wilson, J.
This paper takes stock of the current state of banking systems across Sub-Saharan Africa and discusses recent developments including innovations that might help Africa leapfrog more traditional banking models. Using an array of different data, the paper documents that African banking systems are
PROMOTING ACCESS TO AFRICAN RESEARCH. AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL · RESOURCES ... Anatomy Journal of Africa is the Official Journal for the Association of Anatomical Societies of Africa. ... Applied anatomy - Clinical anatomy - Morphology, - Embryology ...
Peirce, Bonny Norton; Ridge, Stanley G. M.
Reviews recent research in multilingualism in Southern Africa, focusing on the role of languages in education, sociolinguistics, and language policy. Much of the research is on South Africa. Topics discussed include language of instruction in schools, teacher education, higher education, adult literacy, language contact, gender and linguistic…
9 assistance from the National Olympic Committee of South. Africa (NOCSA), while an overwhelming proportion (89%) received no financial support. Of the 45 swimmers surveyed,. 8 respondents were financially supported by Swimming South. Africa, whilst 8 indicated that they were sponsored privately. Twenty-one of the ...
Albertin, Caroline B.; Bonnaud, Laure; Brown, C. Titus
The Cephalopod Sequencing Consortium (CephSeq Consortium) was established at a NESCent Catalysis Group Meeting, ``Paths to Cephalopod Genomics-Strategies, Choices, Organization,'' held in Durham, North Carolina, USA on May 24-27, 2012. Twenty-eight participants representing nine countries (Austria......, Australia, China, Denmark, France, Italy, Japan, Spain and the USA) met to address the pressing need for genome sequencing of cephalopod mollusks. This group, drawn from cephalopod biologists, neuroscientists, developmental and evolutionary biologists, materials scientists, bioinformaticians and researchers...... active in sequencing, assembling and annotating genomes, agreed on a set of cephalopod species of particular importance for initial sequencing and developed strategies and an organization (CephSeq Consortium) to promote this sequencing. The conclusions and recommendations of this meeting are described...
Apperson, Charles S; Engber, Barry; Nicholson, William L; Mead, Daniel G; Engel, Jeffrey; Yabsley, Michael J; Dail, Kathy; Johnson, Joey; Watson, D Wesley
Cases of Rocky Mountain spotted fever (RMSF) in North Carolina have escalated markedly since 2000. In 2005, we identified a county in the Piedmont region with high case numbers of RMSF. We collected ticks and examined them for bacterial pathogens using molecular methods to determine if a novel tick vector or spotted fever group rickettsiae (SFGR) might be emerging. Amblyomma americanum, the lone star tick, comprised 99.6% of 6,502 specimens collected in suburban landscapes. In contrast, Dermacentor variabilis, the American dog tick, a principal vector of Rickettsia rickettsii, comprised < 1% of the ticks collected. Eleven of 25 lone star tick pools tested were infected with "Rickettsia amblyommii," an informally named SFGR. Sera from patients from the same county who were presumptively diagnosed by local physicians with a tick-borne illness were tested by an indirect immunofluorescence antibody (IFA) assay to confirm clinical diagnoses. Three of six patients classified as probable RMSF cases demonstrated a fourfold or greater rise in IgG class antibody titers between paired acute and convalescent sera to "R. amblyommii" antigens, but not to R. rickettsii antigens. White-tailed deer, Odocoileus virginianus, are preferred hosts of lone star ticks. Blood samples collected from hunter-killed deer from the same county were tested by IFA test for antibodies to Ehrlichia chaffeensis and "R. amblyommii." Twenty-eight (87%) of 32 deer were positive for antibodies to E. chaffeensis, but only 1 (3%) of the deer exhibited antibodies to "R. amblyommii," suggesting that deer are not the source of "R. amblyommii" infection for lone star ticks. We propose that some cases of rickettsiosis reported as RMSF may have been caused by "R. amblyommii" transmitted through the bite of A. americanum.
Parola, Philippe; Cornet, Jean-Paul; Sanogo, Yibayiri Osée; Miller, R Scott; Thien, Huynh Van; Gonzalez, Jean-Paul; Raoult, Didier; Telford III, Sam R; Wongsrichanalai, Chansuda
A total of 650 ticks, including 13 species from five genera, were collected from animals, from people, or by flagging of the vegetation at sites on the Thai-Myanmar border and in Vietnam. They were tested by PCR to detect DNA of bacteria of the order RICKETTSIALES: Three Anaplasma spp. were detected in ticks collected in Thailand, including (i) Anaplasma sp. strain AnDa465, which was considered a genotype of Anaplasma platys (formerly Ehrlichia platys) and which was obtained from Dermacentor auratus ticks collected from dogs; (ii) Anaplasma sp. strain AnAj360, which was obtained from Amblyomma javanense ticks collected on a pangolin; and (iii) Anaplasma sp. strain AnHl446, which was closely related to Anaplasma bovis and which was detected in Haemaphysalis lagrangei ticks collected from a bear. Three Ehrlichia spp. were identified, including (i) Ehrlichia sp. strain EBm52, which was obtained from Boophilus microplus ticks collected from cattle from Thailand; (ii) Ehrlichia sp. strain EHh324, which was closely related to Ehrlichia chaffeensis and which was detected in Haemaphysalis hystricis ticks collected from wild pigs in Vietnam; and (iii) Ehrlichia sp. strain EHh317, which was closely related to Ehrlichia sp. strain EBm52 and which was also detected in H. hystricis ticks collected from wild pigs in Vietnam. Two Rickettsia spp. were detected in Thailand, including (i) Rickettsia sp. strain RDla420, which was detected in Dermacentor auratus ticks collected from a bear, and (ii) Rickettsia sp. strain RDla440, which was identified from two pools of Dermacentor larvae collected from a wild pig nest. Finally, two bacteria named Eubacterium sp. strain Hw124 and Eubacterium sp. strain Hw191 were identified in Haemaphysalis wellingtoni ticks collected from chicken in Thailand; these strains could belong to a new group of bacteria.
The 22 Arab nations have a unique genetic structure, which reflects both conserved and diverse gene pools due to the prevalent endogamous and consanguineous marriage culture and the long history of admixture among different ethnic subcultures descended from the Asian, European, and African continents. Human genome sequencing has enabled large-scale genomic studies of different populations and has become a powerful tool for studying disease predictions and diagnosis. Despite the importance of the Arab genome for better understanding the dynamics of the human genome, discovering rare genetic variations, and studying early human migration out of Africa, it is poorly represented in human genome databases, such as HapMap and the 1000 Genomes Project. In this review, I demonstrate the significance of sequencing the Arab genome and setting an Arab genome reference(s) for better understanding the molecular pathogenesis of genetic diseases, discovering novel/rare variants, and identifying a meaningful genotype-phenotype correlation for complex diseases. Copyright © 2016. Published by Elsevier B.V.
Sato, Shusei; Andersen, Stig Uggerhøj
The current Lotus japonicus reference genome sequence is based on a hybrid assembly of Sanger TAC/BAC, Sanger shotgun and Illumina shotgun sequencing data generated from the Miyakojima-MG20 accession. It covers nearly all expressed L. japonicus genes and has been annotated mainly based on transcr......The current Lotus japonicus reference genome sequence is based on a hybrid assembly of Sanger TAC/BAC, Sanger shotgun and Illumina shotgun sequencing data generated from the Miyakojima-MG20 accession. It covers nearly all expressed L. japonicus genes and has been annotated mainly based...
Full Text Available What makes the words ‘Africa’ and ‘African’ possible and useful? In this article it is argued that at least four internally coherent concepts of Africa exist, and that none of these concepts are ethically neutral. The article is presented as a contribution to attempts at using the term ‘Africa’ in self-critical, reflexive and constructive ways. It could therefore be of interest to all researchers, particularly those in the humanities and theology, who locate their research within the context of ‘Africa’. It is argued that Africa can be conceived of as a place, a commodity, a condition and an ideal. By drawing on mostly primary sources it is shown that the term ‘Africa’ only relatively recently came to refer to a continent, that Africa as a place and Africa as a condition in need of betterment formed the foundation for its commodification, and that Africa only very recently became a self-description of the people who live on the continent of Africa. Each of these concepts of Africa is shown to be based on a particular logic with both strengths and weaknesses.
Fayemi, Ademola Kazeem; Macaulay-Adeyelure, O C
The global spread of bioethics from its North-American and European provenance to non-Western societies is currently raising some concerns. Part of the concern has to do with whether or not the exportation of bioethics in its full Western sense to developing non-Western states is an instance of ethical imperialism or bioethical neocolonialism. This paper attempts an exploration of this debate in the context of bioethics in sub-Saharan Africa. Rather than conceding that bioethics has a colonial agenda in Africa, this paper defends the position that the current bioethics trend in sub-Saharan Africa is an unintended imperialistic project. It argues that its colonizing character is not entirely a product of the Western programmed goals of training and institution building; rather, it is a structural consequence of many receptive African minds and institutions. Though bioethics in Africa is turning out as a colonizing project, one serious implication of such trend, if unchecked urgently, is that bioethics' invaluable relevance to Africa is being incapacitated. This paper, therefore, attempts a decolonizing trajectory of bioethics in Africa. Contrary to the pretense of 'African bioethics,' which some African scholars are now defending, this paper through the logic of decolonization makes case for 'bioethics in Africa'. In such logic, the principle of existential needs is prioritized over the principle of identity and authenticity that define African voice in bioethics.
Hoorweg, J.C.; Sexton, V.S.; Msiak, H.
This review of the development and current status of psychology in Africa focuses on Africa south of the Sahara, excluding South Africa. The author discusses the research topics which have attracted the attention of psychologists in Africa, including perception (illusions, pictorial representation
Poverty in Africa has been rising for the last quarter-century, while it has been falling in the rest of the developing world. Africa's distinctive problem is that its economies have not been growing. This article attempts to synthesize a range of recent research to account for this failure of the growth process. I argue that the reasons lie not in African peculiarities but rather in geographic features that globally cause problems but that are disproportionately pronounced in Africa. These features interact to create three distinct challenges that are likely to require international interventions beyond the conventional reliance on aid.
Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 8. Comparative Genomics - A Powerful New Tool in Biology. Anand K Bachhawat. General Article Volume 11 Issue 8 August 2006 pp 22-40. Fulltext. Click here to view fulltext PDF. Permanent link:
Tamrakar Sushil B
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.
Healy, Sean P; Brown, Lisa D; Hagstrom, Melena R; Foil, Lane D; Macaluso, Kevin R
Rickettsia felis is a human pathogen transmitted by the cat flea, Ctenocephalides felis (Bouché) (str. LSU), as well as an obligate symbiont of the parthenogenic booklouse Liposcelis bostrychophila (Badonnel) (str. LSU-Lb). The influence of genetic variability in these two strains of R. felis on host specialization and fitness and possible resulting differences on infection and transmission kinetics in C. felis is unknown. Utilizing an artificial host system, cat fleas were exposed to a R. felis str. LSU-Lb-infected bloodmeal and monitored for infection at 7-d intervals for 28 d. Quantitative real-time PCR was used to determine rickettsial load and infection density in newly exposed cat fleas, and transmission frequency between cat fleas. The effect of persistent R. felis infection on cat flea F1 progeny was also assessed. At 7 d postexposure 76.7% of the cat fleas successfully acquired R. felis str. LSU-Lb. In R. felis str. LSU-Lb-exposed cat fleas, the mean infection load (6.15 × 106), infection density (0.76), and infection prevalence (91/114) were significantly greater than R. felis str. LSU infection load (3.09 × 106), infection density (0.68), and infection prevalence (76/113). A persistent R. felis str. LSU-Lb infection was detected for 28 d in adult cat fleas but neither female:male ratio distortion nor vertical transmission was observed in F1 progeny. While infection kinetics differed, with higher intensity associated with R. felis str. LSU-Lb, no distinct phenotype was observed in the F1 progeny. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
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.
Lukovsky-Akhsanov, Nicole; Keating, M Kelly; Spivey, Pamela; Lathrop, George W; Powell, Nathaniel; Levin, Michael L
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
Pickrell, Joseph K; Patterson, Nick; Barbieri, Chiara; Berthold, Falko; Gerlach, Linda; Güldemann, Tom; Kure, Blesswell; Mpoloka, Sununguko Wata; Nakagawa, Hirosi; Naumann, Christfried; Lipson, Mark; Loh, Po-Ru; Lachance, Joseph; Mountain, Joanna; Bustamante, Carlos D; Berger, Bonnie; Tishkoff, Sarah A; Henn, Brenna M; Stoneking, Mark; Reich, David; Pakendorf, Brigitte
Southern and eastern African populations that speak non-Bantu languages with click consonants are known to harbour some of the most ancient genetic lineages in humans, but their relationships are poorly understood. Here, we report data from 23 populations analysed at over half a million single-nucleotide polymorphisms, using a genome-wide array designed for studying human history. The southern African Khoisan fall into two genetic groups, loosely corresponding to the northwestern and southeastern Kalahari, which we show separated within the last 30,000 years. We find that all individuals derive at least a few percent of their genomes from admixture with non-Khoisan populations that began ∼1,200 years ago. In addition, the East African Hadza and Sandawe derive a fraction of their ancestry from admixture with a population related to the Khoisan, supporting the hypothesis of an ancient link between southern and eastern Africa.
Stoneking, Mark; Krause, Johannes
Genome-wide data, both from SNP arrays and from complete genome sequencing, are becoming increasingly abundant and are now even available from extinct hominins. These data are providing new insights into population history; in particular, when combined with model-based analytical approaches, genome-wide data allow direct testing of hypotheses about population history. For example, genome-wide data from both contemporary populations and extinct hominins strongly support a single dispersal of modern humans from Africa, followed by two archaic admixture events: one with Neanderthals somewhere outside Africa and a second with Denisovans that (so far) has only been detected in New Guinea. These new developments promise to reveal new stories about human population history, without having to resort to storytelling.
May 12, 2015 ... to benefit from its problematic socio-political history is an indication that there are different and often contradictory .... This is illustrated by the early geographical .... West Africa and Togo, with the acquisition of German East.
Sociology, Faculty of Arts and Sciences, Harvard University, USA. ... publication, the book Student Politics in Africa: Representation and Activism, published .... reference to two moments in the country's student political history: the 1973 student.
challenges remain. ... such issues as environmental preserva- tion, new ... women's access to land. ... Youth in South Africa face many hurdles, ... works like family and friends to overcome chal- ... representatives, local businesses, and gov-.
in statistics from the university of ibadan, holds a master's degree in business administration and in ... institute of business science (gibs), university of Pretoria, south africa. Rilwan is a. Fellow of .... the pace of economic and social development ...
Manufactured tobacco production in Cameroon (tons) ... Africa has a responsibility to resist the carrot of industrial temptation. ...... parliamentary systems, unitary versus federal designs and the relative development and influence of the judicial ...
Mentally handicapped children were screened in 5 countries in Africa in order to explore the usefulness of Western criteria for the recognition of childhood autism in children from developing countries. (CM)
The vision for astronomy in Africa is embedded in the African Space Policy of the African Union in early 2014. The vision is about positioning Africa as an emerging hub for astronomy sciences and facilities. Africa recognized the need to take advantage of its natural resource, the geographical advantage of the clear southern skies and pristine sites for astronomy. The Pan African University (PAU) initiative also presents an opportunity as a post-graduate training and research network of university nodes in five regions of Africa and supported by the African Union. The Southern African node based in South Africa concentrates on space sciences which also includes astronomy. The PAU aims to provide the opportunity for advanced graduate training and postgraduate research to high-performing African students. Objectives also include promoting mobility of students and teachers and harmonizing programs and degrees.A number of astronomy initiatives have burgeoned in the Southern African region and these include the Southern Africa Largest Optical Telescope (SALT), HESS (High Energy Stereoscopic System), the SKA (Square Kilometre Array) and the AVN (African Very Long Baseline Interferometer Network). There is a growing appetite for astronomy sciences in Africa. In East Africa, the astronomy community is well organized and is growing - the East African Astronomical society (EAAS) held its successful fourth annual conference since 2010 on 30 June to 04 July 2014 at the University of Rwanda. Centred around the 'Role of Astronomy in Socio-Economic Transformation,' this conference aimed at strengthening capacity building in Astronomy, Astrophysics and Space Science in general, while providing a forum for astronomers from the region to train young and upcoming scientists.
Hernes, Helga; Dalfelt, Arne; Berntsen, Terje; Holtsmark, Bjart; Næss, Lars Otto; Selrod, Rolf; Aaheim, H. Asbjørn
1. General observations Africa south of the Sahara is probably the most vulnerable region when it comes to the impact and consequences of climate changes. Yet the African continent runs a serious risk of being marginalized in the global dialogue on climate issues. Africa contributes little to the global emissions of CO2, and other greenhouse gases. The major focus of the Framework Convention on Climate Change is on abatement and mitigation of emissions rather than adaptation to the con...
The paper discusses the role of basic sciences in the development of technology. This is then tied up with the broader issue of the importance of scientific and technological knowledge in the socio-economic development of a country. Physics forms the basis for most of the natural and applied sciences and technology. The state of physics in Africa is reviewed. The need for regional and international cooperation in physics education and research in Africa is stressed. (author). 13 refs, 2 tabs
Allotey, F K.A.
The paper discusses the role of basic sciences in the development of technology. This is then tied up with the broader issue of the importance of scientific and technological knowledge in the socio-economic development of a country. Physics forms the basis for most of the natural and applied sciences and technology. The state of physics in Africa is reviewed. The need for regional and international cooperation in physics education and research in Africa is stressed. (author). 13 refs, 2 tabs.
Sub-Saharan Africa, with its mining and petroleum resources, is still the object of covetous desires from developed countries. The Gulf of Guinea is a promising area and probably the future battlefield of the 21. century. The fighters of this war are the African people and the big powers, the USA and China at the head, who call upon mercenaries to get their share of this fabulous treasure. Oil was a chance for Africa, but now oil is killing it
Difficulties with this romantic concept developed, however, when General Faidherbe began to expand French control into the Senegalese hinterland. He was...and his German 45 France in Black Africa friends to gain greater control of the AOF.6 The tragi- comedy ended with the 1942 Allied landings in North...service]). Trinquier’s own stay in Africa was short-lived. Belgian resistance to a French invasion of their turf was fierce. Trinquier’s romantic
The global spread of bioethics from its North-American and European provenance to non-Western societies is currently raising some concerns. Part of the concern has to do with whether or not the exportation of bioethics in its full Western sense to developing non-Western states is an instance of ethical imperialism or bioethical neocolonialism. This paper attempts an exploration of this debate in the context of bioethics in sub-Saharan Africa. Rather than conceding that bioethics has a colonial agenda in Africa, this paper defends the position that the current bioethics trend in sub-Saharan Africa is an unintended imperialistic project. It argues that its colonizing character is not entirely a product of the Western programmed goals of training and institution building; rather, it is a structural consequence of many receptive African minds and institutions. Though bioethics in Africa is turning out as a colonizing project, one serious implication of such trend, if unchecked urgently, is that bioethics’ invaluable relevance to Africa is being incapacitated. This paper, therefore, attempts a decolonizing trajectory of bioethics in Africa. Contrary to the pretense of ‘African bioethics,’ which some African scholars are now defending, this paper through the logic of decolonization makes case for ‘bioethics in Africa’. In such logic, the principle of existential needs is prioritized over the principle of identity and authenticity that define African voice in bioethics. PMID:28344985
Moisés Sihuincha M
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.
Galina E Zemtsova
Full Text Available Studies on the natural transmission cycles of zoonotic pathogens and the reservoir competence of vertebrate hosts require methods for reliable diagnosis of infection in wild and laboratory animals. Several PCR-based applications have been developed for detection of infections caused by Spotted Fever group Rickettsia spp. in a variety of animal tissues. These assays are being widely used by researchers, but they differ in their sensitivity and reliability. We compared the sensitivity of five previously published conventional PCR assays and one SYBR green-based real-time PCR assay for the detection of rickettsial DNA in blood and tissue samples from Rickettsia- infected laboratory animals (n = 87. The real-time PCR, which detected rickettsial DNA in 37.9% of samples, was the most sensitive. The next best were the semi-nested ompA assay and rpoB conventional PCR, which detected as positive 18.4% and 14.9% samples respectively. Conventional assays targeting ompB, gltA and hrtA genes have been the least sensitive. Therefore, we recommend the SYBR green-based real-time PCR as a tool for the detection of rickettsial DNA in animal samples due to its higher sensitivity when compared to more traditional assays.
Zemtsova, Galina E; Montgomery, Merrill; Levin, Michael L
Studies on the natural transmission cycles of zoonotic pathogens and the reservoir competence of vertebrate hosts require methods for reliable diagnosis of infection in wild and laboratory animals. Several PCR-based applications have been developed for detection of infections caused by Spotted Fever group Rickettsia spp. in a variety of animal tissues. These assays are being widely used by researchers, but they differ in their sensitivity and reliability. We compared the sensitivity of five previously published conventional PCR assays and one SYBR green-based real-time PCR assay for the detection of rickettsial DNA in blood and tissue samples from Rickettsia- infected laboratory animals (n = 87). The real-time PCR, which detected rickettsial DNA in 37.9% of samples, was the most sensitive. The next best were the semi-nested ompA assay and rpoB conventional PCR, which detected as positive 18.4% and 14.9% samples respectively. Conventional assays targeting ompB, gltA and hrtA genes have been the least sensitive. Therefore, we recommend the SYBR green-based real-time PCR as a tool for the detection of rickettsial DNA in animal samples due to its higher sensitivity when compared to more traditional assays.
Gurwitz, David; Bregman-Eschet, Yael
New companies offering personal whole-genome information services over the internet are dynamic and highly visible players in the personal genomics field. For fees currently ranging from US$399 to US$2500 and a vial of saliva, individuals can now purchase online access to their individual genetic information regarding susceptibility to a range of chronic diseases and phenotypic traits based on a genome-wide SNP scan. Most of the companies offering such services are based in the United States, but their clients may come from nearly anywhere in the world. Although the scientific validity, clinical utility and potential future implications of such services are being hotly debated, several ethical and regulatory questions related to direct-to-consumer (DTC) marketing strategies of genetic tests have not yet received sufficient attention. For example, how can we minimize the risk of unauthorized third parties from submitting other people's DNA for testing? Another pressing question concerns the ownership of (genotypic and phenotypic) information, as well as the unclear legal status of customers regarding their own personal information. Current legislation in the US and Europe falls short of providing clear answers to these questions. Until the regulation of personal genomics services catches up with the technology, we call upon commercial providers to self-regulate and coordinate their activities to minimize potential risks to individual privacy. We also point out some specific steps, along the trustee model, that providers of DTC personal genomics services as well as regulators and policy makers could consider for addressing some of the concerns raised below.
Pierron, Denis; Heiske, Margit; Razafindrazaka, Harilanto; Rakoto, Ignace; Rabetokotany, Nelly; Ravololomanga, Bodo; Rakotozafy, Lucien M.-A.; Rakotomalala, Mireille Mialy; Razafiarivony, Michel; Rasoarifetra, Bako; Raharijesy, Miakabola Andriamampianina; Razafindralambo, Lolona; Ramilisonina; Fanony, Fulgence; Lejamble, Sendra; Thomas, Olivier; Mohamed Abdallah, Ahmed; Rocher, Christophe; Arachiche, Amal; Tonaso, Laure; Pereda-loth, Veronica; Schiavinato, Stéphanie; Brucato, Nicolas; Ricaut, Francois-Xavier; Kusuma, Pradiptajati; Sudoyo, Herawati; Ni, Shengyu; Boland, Anne; Deleuze, Jean-Francois; Beaujard, Philippe; Grange, Philippe; Adelaar, Sander; Stoneking, Mark; Rakotoarisoa, Jean-Aimé; Radimilahy, Chantal; Letellier, Thierry
Although situated ∼400 km from the east coast of Africa, Madagascar exhibits cultural, linguistic, and genetic traits from both Southeast Asia and Eastern Africa. The settlement history remains contentious; we therefore used a grid-based approach to sample at high resolution the genomic diversity (including maternal lineages, paternal lineages, and genome-wide data) across 257 villages and 2,704 Malagasy individuals. We find a common Bantu and Austronesian descent for all Malagasy individuals with a limited paternal contribution from Europe and the Middle East. Admixture and demographic growth happened recently, suggesting a rapid settlement of Madagascar during the last millennium. However, the distribution of African and Asian ancestry across the island reveals that the admixture was sex biased and happened heterogeneously across Madagascar, suggesting independent colonization of Madagascar from Africa and Asia rather than settlement by an already admixed population. In addition, there are geographic influences on the present genomic diversity, independent of the admixture, showing that a few centuries is sufficient to produce detectable genetic structure in human populations. PMID:28716916
Nathalie Costa da Cunha
Full Text Available ABSTRACT. Cunha N.C., Lemos E.R.S., Rozental T., Teixeira R.C., Cordeiro M.D., Lisbôa R.S., Favacho A.R., Barreira J.D., Rezende J. & Fonseca A.H. Rickettsiae of the Spotted Fever group in dogs, horses and ticks: an epidemiological study in an endemic region of the State of Rio de Janeiro, Brazil. [Rickettsias do grupo da febre maculosa em cães, equinos e carrapatos: um estudo epidemiológico em região endêmica do estado do Rio de Janeiro, Brasil.] Revista Brasileira de Medicina Veterinária, 36(3:294-300, 2014. Departamento de Epidemiologia e Saúde Pública, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, BR 465, Km 7, Seropédica, RJ 23890-000, Brasil. E-mail: email@example.com Spotted fever is a disease of which Rickettsia rickettsii is the most pathogenic agent. Its transmission is by tick bites and the infected ticks can act as vectors, reservoirs or amplifiers. The purpose of this paper is to assess the potential of dogs and horses as sentinels for brazilian spotted fever (BSF emergence and become acquainted with the tick species in a municipal region of Resende, Rio de Janeiro State, Brazil, where five BSF cases in man were registered. Dog and horse blood samples were collected from rural and periurban properties to assess IgG anti-Rickettsia rickettsii, using the indirect immunofluorescence assay (IFA. First, an analysis was conducted to detect association between IFA results and answers obtained from a questionnaire. Afterwards, a multivariate investigation was undertaken that presented significant statistical differences. Ticks were collected directly from dogs and horses for taxonomic identification. Out of the 107 canine serum samples, 30 (28.0% were reactive, with titers varying from 1:64 to 1:4096, and 77 (72.0% were not reactive. Of 96 animals in the serum analysis of horses, 9 (9.4% were reactive, all with titers of 1:64, and 87 (90.6% were non-reactive. The tick species collected from dogs were
Kerkhoven, R.; Enckevort, F.H.J. van; Boekhorst, J.; Molenaar, D; Siezen, R.J.
SUMMARY: A Web-based visualization tool, the Microbial Genome Viewer, is presented that allows the user to combine complex genomic data in a highly interactive way. This Web tool enables the interactive generation of chromosome wheels and linear genome maps from genome annotation data stored in a
Full Text Available The dawning of the 21st century generally brought new hope to African leaders and countless thousands of ordinary citizens of many countries on the continent. The first signs of a new turn of events shone through by the end of the last decade of the previous century. This was manifested by economic growth rates that started to pick up in a number of African states, by pro-democracy movements which in country after country succeeded in replacing authoritarian regimes, and by the winding down and termination of some of Africa’s most devastating wars. The results of this analysis confirm the above-mentioned positive political, economic and conflict trends in Africa. It is clearly a significant turn of events given the well-known political and economic predicament with which Africa is struggling. When this negative legacy and Cold War background of Africa is considered, the importance of present developments is clear to see. The identified heightened sense of purpose among the leaders and peoples of Africa and the changed mood and need among Africans to take charge of their own future that found expression in the New Partnership for Africa’s Development (NEPAD are indeed significant and bode well for the future of the continent. A word of warning here is, however, necessary. Our conduct with Africa must be very cautious and we must guard against over-optimism and the exaggerated belief that Africa is now on a trajectory of sustained development and peace. We cannot generalise about Africa – for that the continent is just too big and diverse from a geographical, cultural, economic and political point of view.
Mulder, Nicola J.; Adebiyi, Ezekiel; Alami, Raouf; Benkahla, Alia; Brandful, James; Doumbia, Seydou; Everett, Dean; Fadlelmola, Faisal M.; Gaboun, Fatima; Gaseitsiwe, Simani; Ghazal, Hassan; Hazelhurst, Scott; Hide, Winston; Ibrahimi, Azeddine; Jaufeerally Fakim, Yasmina; Jongeneel, C. Victor; Joubert, Fourie; Kassim, Samar; Kayondo, Jonathan; Kumuthini, Judit; Lyantagaye, Sylvester; Makani, Julie; Mansour Alzohairy, Ahmed; Masiga, Daniel; Moussa, Ahmed; Nash, Oyekanmi; Ouwe Missi Oukem-Boyer, Odile; Owusu-Dabo, Ellis; Panji, Sumir; Patterton, Hugh; Radouani, Fouzia; Sadki, Khalid; Seghrouchni, Fouad; Tastan Bishop, Özlem; Tiffin, Nicki; Ulenga, Nzovu
The application of genomics technologies to medicine and biomedical research is increasing in popularity, made possible by new high-throughput genotyping and sequencing technologies and improved data analysis capabilities. Some of the greatest genetic diversity among humans, animals, plants, and microbiota occurs in Africa, yet genomic research outputs from the continent are limited. The Human Heredity and Health in Africa (H3Africa) initiative was established to drive the development of genomic research for human health in Africa, and through recognition of the critical role of bioinformatics in this process, spurred the establishment of H3ABioNet, a pan-African bioinformatics network for H3Africa. The limitations in bioinformatics capacity on the continent have been a major contributory factor to the lack of notable outputs in high-throughput biology research. Although pockets of high-quality bioinformatics teams have existed previously, the majority of research institutions lack experienced faculty who can train and supervise bioinformatics students. H3ABioNet aims to address this dire need, specifically in the area of human genetics and genomics, but knock-on effects are ensuring this extends to other areas of bioinformatics. Here, we describe the emergence of genomics research and the development of bioinformatics in Africa through H3ABioNet. PMID:26627985
.... It is argued the current Unified Command Plan is ill designed to address the complexities of the continent of Africa and that a proposed United States Africa Command would be better positioned...
Witkowski, Peter T; Klempa, Boris; Ithete, Ndapewa L; Auste, Brita; Mfune, John K E; Hoveka, Julia; Matthee, Sonja; Preiser, Wolfgang; Kruger, Detlev H
This paper summarizes the progress in the search for hantaviruses and hantavirus infections in Africa. After having collected molecular evidence of an indigenous African hantavirus in 2006, an intensive investigation for new hantaviruses has been started in small mammals. Various novel hantaviruses have been molecularly identified not only in rodents but also in shrews and bats. In addition, the first African hantavirus, Sangassou virus, has been isolated and functionally characterized in cell culture. Less is known about the ability of these hantaviruses to infect humans and to cause diseases. To date, no hantavirus genetic material could be amplified from patients' specimens collected in Africa. Serological studies in West Africa, based on a battery of screening and confirmatory assays, led to the detection of hantavirus antibodies in the human population and in patients with putative hantavirus disease. In addition to this overview, we present original data from seroepidemiological and field studies conducted in the Southern part of Africa. A human seroprevalence rate of 1.0% (n=1442) was detected in the South African Cape Region whereas no molecular evidence for the presence of hantavirus was found in 2500 small animals trapped in South Africa and Namibia. Copyright © 2014 Elsevier B.V. All rights reserved.
Hodgson, Jason A.; Mulligan, Connie J.; Al-Meeri, Ali; Raaum, Ryan L.
Genetic studies have identified substantial non-African admixture in the Horn of Africa (HOA). In the most recent genomic studies, this non-African ancestry has been attributed to admixture with Middle Eastern populations during the last few thousand years. However, mitochondrial and Y chromosome data are suggestive of earlier episodes of admixture. To investigate this further, we generated new genome-wide SNP data for a Yemeni population sample and merged these new data with published genome-wide genetic data from the HOA and a broad selection of surrounding populations. We used multidimensional scaling and ADMIXTURE methods in an exploratory data analysis to develop hypotheses on admixture and population structure in HOA populations. These analyses suggested that there might be distinct, differentiated African and non-African ancestries in the HOA. After partitioning the SNP data into African and non-African origin chromosome segments, we found support for a distinct African (Ethiopic) ancestry and a distinct non-African (Ethio-Somali) ancestry in HOA populations. The African Ethiopic ancestry is tightly restricted to HOA populations and likely represents an autochthonous HOA population. The non-African ancestry in the HOA, which is primarily attributed to a novel Ethio-Somali inferred ancestry component, is significantly differentiated from all neighboring non-African ancestries in North Africa, the Levant, and Arabia. The Ethio-Somali ancestry is found in all admixed HOA ethnic groups, shows little inter-individual variance within these ethnic groups, is estimated to have diverged from all other non-African ancestries by at least 23 ka, and does not carry the unique Arabian lactase persistence allele that arose about 4 ka. Taking into account published mitochondrial, Y chromosome, paleoclimate, and archaeological data, we find that the time of the Ethio-Somali back-to-Afric