Novel strategy for generation and titration of recombinant adeno-associated virus vectors.

Science.gov (United States)

Shiau, Ai-Li; Liu, Pu-Ste; Wu, Chao-Liang

2005-01-01

Recombinant adeno-associated virus (rAAV) vectors have many advantages for gene therapeutic applications compared with other vector systems. Several methods that use plasmids or helper viruses have been reported for the generation of rAAV vectors. Unfortunately, the preparation of large-scale rAAV stocks is labor-intensive. Moreover, the biological titration of rAAV is still difficult, which may limit its preclinical and clinical applications. For this study, we developed a novel strategy to generate and biologically titrate rAAV vectors. A recombinant pseudorabies virus (PrV) with defects in its gD, gE, and thymidine kinase genes was engineered to express the AAV rep and cap genes, yielding PS virus, which served as a packaging and helper virus for the generation of rAAV vectors. PS virus was useful not only for generating high-titer rAAV vectors by cotransfection with an rAAV vector plasmid, but also for amplifying rAAV stocks. Notably, the biological titration of rAAV vectors was also feasible when cells were coinfected with rAAV and PS virus. Based on this strategy, we produced an rAAV that expresses prothymosin alpha (ProT). Expression of the ProT protein in vitro and in vivo mediated by rAAV/ProT gene transfer was detected by immunohistochemistry and a bioassay. Taken together, our results demonstrate that the PrV vector-based system is useful for generating rAAV vectors carrying various transgenes.

Herpes simplex virus type 1-derived recombinant and amplicon vectors.

Science.gov (United States)

Fraefel, Cornel; Marconi, Peggy; Epstein, Alberto L

2011-01-01

Herpes simplex virus type 1 (HSV-1) is a human pathogen whose lifestyle is based on a long-term dual interaction with the infected host, being able to establish both lytic and latent infections. The virus genome is a 153 kbp double-stranded DNA molecule encoding more than 80 genes. The interest of HSV-1 as gene transfer vector stems from its ability to infect many different cell types, both quiescent and proliferating cells, the very high packaging capacity of the virus capsid, the outstanding neurotropic adaptations that this virus has evolved, and the fact that it never integrates into the cellular chromosomes, thus avoiding the risk of insertional mutagenesis. Two types of vectors can be derived from HSV-1, recombinant vectors and amplicon vectors, and different methodologies have been developed to prepare large stocks of each type of vector. This chapter summarizes (1) the two approaches most commonly used to prepare recombinant vectors through homologous recombination, either in eukaryotic cells or in bacteria, and (2) the two methodologies currently used to generate helper-free amplicon vectors, either using a bacterial artificial chromosome (BAC)-based approach or a Cre/loxP site-specific recombination strategy.

Chikungunya Virus Vaccines: Viral Vector-Based Approaches.

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Ramsauer, Katrin; Tangy, Frédéric

2016-12-15

In 2013, a major chikungunya virus (CHIKV) epidemic reached the Americas. In the past 2 years, >1.7 million people have been infected. In light of the current epidemic, with millions of people in North and South America at risk, efforts to rapidly develop effective vaccines have increased. Here, we focus on CHIKV vaccines that use viral-vector technologies. This group of vaccine candidates shares an ability to potently induce humoral and cellular immune responses by use of highly attenuated and safe vaccine backbones. So far, well-described vectors such as modified vaccinia virus Ankara, complex adenovirus, vesicular stomatitis virus, alphavirus-based chimeras, and measles vaccine Schwarz strain (MV/Schw) have been described as potential vaccines. We summarize here the recent data on these experimental vaccines, with a focus on the preclinical and clinical activities on the MV/Schw-based candidate, which is the first CHIKV-vectored vaccine that has completed a clinical trial. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Differential Persistence of Foot-and-Mouth Disease Virus in African Buffalo Is Related to Virus Virulence.

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Maree, Francois; de Klerk-Lorist, Lin-Mari; Gubbins, Simon; Zhang, Fuquan; Seago, Julian; Pérez-Martín, Eva; Reid, Liz; Scott, Katherine; van Schalkwyk, Louis; Bengis, Roy; Charleston, Bryan; Juleff, Nicholas

2016-05-15

Foot-and-mouth disease (FMD) virus (FMDV) circulates as multiple serotypes and strains in many regions of endemicity. In particular, the three Southern African Territories (SAT) serotypes are maintained effectively in their wildlife reservoir, the African buffalo, and individuals may harbor multiple SAT serotypes for extended periods in the pharyngeal region. However, the exact site and mechanism for persistence remain unclear. FMD in buffaloes offers a unique opportunity to study FMDV persistence, as transmission from carrier ruminants has convincingly been demonstrated for only this species. Following coinfection of naive African buffaloes with isolates of three SAT serotypes from field buffaloes, palatine tonsil swabs were the sample of choice for recovering infectious FMDV up to 400 days postinfection (dpi). Postmortem examination identified infectious virus for up to 185 dpi and viral genomes for up to 400 dpi in lymphoid tissues of the head and neck, focused mainly in germinal centers. Interestingly, viral persistence in vivo was not homogenous, and the SAT-1 isolate persisted longer than the SAT-2 and SAT-3 isolates. Coinfection and passage of these SAT isolates in goat and buffalo cell lines demonstrated a direct correlation between persistence and cell-killing capacity. These data suggest that FMDV persistence occurs in the germinal centers of lymphoid tissue but that the duration of persistence is related to virus replication and cell-killing capacity. Foot-and-mouth disease virus (FMDV) causes a highly contagious acute vesicular disease in domestic livestock and wildlife species. African buffaloes (Syncerus caffer) are the primary carrier hosts of FMDV in African savannah ecosystems, where the disease is endemic. We have shown that the virus persists for up to 400 days in buffaloes and that there is competition between viruses during mixed infections. There was similar competition in cell culture: viruses that killed cells quickly persisted more

Nora virus persistent infections are not affected by the RNAi machinery.

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Habayeb, Mazen S; Ekström, Jens-Ola; Hultmark, Dan

2009-05-29

Drosophila melanogaster is widely used to decipher the innate immune system in response to various pathogens. The innate immune response towards persistent virus infections is among the least studied in this model system. We recently discovered a picorna-like virus, the Nora virus which gives rise to persistent and essentially symptom-free infections in Drosophila melanogaster. Here, we have used this virus to study the interaction with its host and with some of the known Drosophila antiviral immune pathways. First, we find a striking variability in the course of the infection, even between flies of the same inbred stock. Some flies are able to clear the Nora virus but not others. This phenomenon seems to be threshold-dependent; flies with a high-titer infection establish stable persistent infections, whereas flies with a lower level of infection are able to clear the virus. Surprisingly, we find that both the clearance of low-level Nora virus infections and the stability of persistent infections are unaffected by mutations in the RNAi pathways. Nora virus infections are also unaffected by mutations in the Toll and Jak-Stat pathways. In these respects, the Nora virus differs from other studied Drosophila RNA viruses.

Persistence of enteric viruses within oysters (Crassostrea virginica)

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It is well known that water-borne enteric viruses are concentrated by bivalves. Why these viruses are selectively retained and remain infectious within shellfish tissues for extended periods is unknown. Our current hypothesis is that phagocytic hemocytes (blood cells) are a site of virus persiste...

Effects of interferon on cultured cells persistently infected with viruses

Energy Technology Data Exchange (ETDEWEB)

Crespi, M

1986-01-01

The role of interferon (IFN) in viral persistence at the cellular level was investigated. Two types of persistent infections were chosen. The first type was cell lines which contained hepatitis B virus (HBV) DNA (PLC/PRF/5 and Hep 3B cells) uninfected control hepatoma cells, (Mahlavu, HA22T and Hep G2 cells) or simian virus 40 (SV40) DNA (C2, C6, C11 cells) and control uninfected (CV-1 cells). In the second type of infection Vero cells persistently infected with SSPE or Sendai virus were used. The aim of this work was to determine what effect IFN had in these infections in terms of its antiviral and antiproliferative effects; which of the two major IFN-induced pathways, E enzyme or protein kinase were induced; whether there were any differences in sensitivity to IFN between the DNA and RNA virus persistent infections. The anti-viral effect of IFN was examined by its ability to inhibit Sindbis virus replication using a radioimmunoassay system. The antiproliferative effect of IFN was determined by cell counting and /sup 3/H-thymidine incorporation. The activation of the ribonuclease F, determined by the inhibition of /sup 3/H-leucine incorporation after introduction of 2-5 actin into the cells, was variable, being activated in all cell lines with the exception of the PLC/PRF/5, Hep 3B and Hep G2 cells. Major differences between the two DNA persistent infections and the two RNA persistent infections were found. No correlation was found between the presence of HBV or SV40 persistent infections and the sensitivity of the cell lines to IFN. Both the SSPE and Sendai virus persistent infections were resistant to the antiviral and antiproliferative effect of IFN.

Progress and prospects: foamy virus vectors enter a new age.

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Erlwein, O; McClure, M O

2010-12-01

Foamy viruses, distantly related to the major subfamily of Retroviruses, Orthoretroviruses that include oncoviruses (for example, murine leukemia virus (MLV)) and lentiviruses (human immunodeficiency virus (HIV)), are endemic in mammalian species, but not in human populations. Humans infected by accidental or occupational exposure remain well. The virus is not transmitted to others, nor is it associated with any disease. These features added to its broad host range, efficient transduction of progenitor cells and an integration profile less likely to induce insertional mutagenesis, make these viruses attractive as vectors. Long-term reversal of disease phenotype in dogs with the genetic defect, leukocyte adhesion deficiency, by foamy virus vector therapy strengthens the case for their clinical exploitation.

Persistent hepatitis virus infection and immune homeostasis

OpenAIRE

ZHOU Yun

2014-01-01

Homeostasis between the host and viruses is naturally maintained. On the one hand, the immune system activates the immune response to kill or eliminate viruses; on the other hand, the immune system controls the immune response to maintain immune homeostasis. The cause of persistent infections with hepatitis viruses such as HBV and HCV is that viral molecules damage the immune system of the host and their variants escape immune clearance. Long-term coexistence of the host and viruses is the pr...

Virus Database and Online Inquiry System Based on Natural Vectors.

Science.gov (United States)

Dong, Rui; Zheng, Hui; Tian, Kun; Yau, Shek-Chung; Mao, Weiguang; Yu, Wenping; Yin, Changchuan; Yu, Chenglong; He, Rong Lucy; Yang, Jie; Yau, Stephen St

2017-01-01

We construct a virus database called VirusDB (http://yaulab.math.tsinghua.edu.cn/VirusDB/) and an online inquiry system to serve people who are interested in viral classification and prediction. The database stores all viral genomes, their corresponding natural vectors, and the classification information of the single/multiple-segmented viral reference sequences downloaded from National Center for Biotechnology Information. The online inquiry system serves the purpose of computing natural vectors and their distances based on submitted genomes, providing an online interface for accessing and using the database for viral classification and prediction, and back-end processes for automatic and manual updating of database content to synchronize with GenBank. Submitted genomes data in FASTA format will be carried out and the prediction results with 5 closest neighbors and their classifications will be returned by email. Considering the one-to-one correspondence between sequence and natural vector, time efficiency, and high accuracy, natural vector is a significant advance compared with alignment methods, which makes VirusDB a useful database in further research.

Dynamics and Biocontrol: The Indirect Effects of a Predator Population on a Host-Vector Disease Model

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Fengyan Zhou

2014-01-01

Full Text Available A model of the interactions among a host population, an insect-vector population, which transmits virus from hosts to hosts, and a vector predator population is proposed based on virus-host, host-vector, and prey (vector-enemy theories. The model is investigated to explore the indirect effect of natural enemies on host-virus dynamics by reducing the vector densities, which shows the basic reproduction numbers R01 (without predators and R02 (with predators that provide threshold conditions on determining the uniform persistence and extinction of the disease in a host population. When the model is absent from predator, the disease is persistent if R01>1; in such a case, by introducing predators of a vector, then the insect-transmitted disease will be controlled if R02<1. From the point of biological control, these results show that an additional predator population of the vector may suppress the spread of vector-borne diseases. In addition, there exist limit cycles with persistence of the disease or without disease in presence of predators. Finally, numerical simulations are conducted to support analytical results.

Virus infection of a weed increases vector attraction to and vector fitness on the weed.

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Chen, Gong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Fang, Yong; Shi, Xiaobin; Zhang, Youjun

2013-01-01

Weeds are important in the ecology of field crops, and when crops are harvested, weeds often become the main hosts for plant viruses and their insect vectors. Few studies, however, have examined the relationships between plant viruses, vectors, and weeds. Here, we investigated how infection of the weed Datura stramonium L. by tomato yellow leaf curl virus (TYLCV) affects the host preference and performance of the TYLCV vector, Bemisia tabaci (Gennadius) Q. The results of a choice experiment indicated that B. tabaci Q preferentially settled and oviposited on TYLCV-infected plants rather than on healthy plants. In addition, B. tabaci Q performed better on TYLCV-infected plants than on healthy plants. These results demonstrate that TYLCV is indirectly mutualistic to B. tabaci Q. The mutually beneficial interaction between TYLCV and B. tabaci Q may help explain the concurrent outbreaks of TYLCV and B. tabaci Q in China.

Comparative Efficacy of Feline Leukemia Virus (FeLV) Inactivated Whole-Virus Vaccine and Canarypox Virus-Vectored Vaccine during Virulent FeLV Challenge and Immunosuppression.

Science.gov (United States)

Patel, M; Carritt, K; Lane, J; Jayappa, H; Stahl, M; Bourgeois, M

2015-07-01

Four vaccines for feline leukemia virus (FeLV) are available in the United States. This study's purpose was to compare the efficacy of Nobivac feline 2-FeLV (an inactivated, adjuvanted whole-virus vaccine) and PureVax recombinant FeLV (a live, canarypox virus-vectored vaccine) following FeLV challenge. Cats were vaccinated at 9 and 12 weeks with Nobivac feline 2-FeLV (group A, n = 11) or PureVax recombinant FeLV (group B, n = 10). Group C (n = 11) comprised unvaccinated controls. At 3 months postvaccination, cats were immunosuppressed and challenged with FeLV-A/61E. The outcomes measured were persistent antigenemia at 12 weeks postchallenge (PC) and proviral DNA and viral RNA at 3 to 9 weeks PC. Persistent antigenemia was observed in 0 of 11 cats in group A, 5 of 10 cats in group B, and 10 of 11 cats in group C. Group A was significantly protected compared to those in groups B (P 0.063). The preventable fraction was 100% for group A and 45% for group B. At 9 weeks PC, proviral DNA and viral RNA were detected 1 of 11 cats in group A, 6 of 10 cats in group B, and 9 of 11 cats in group C. Nucleic acid loads were significantly lower in group A than in group C (P feline 2-FeLV-vaccinated cats were fully protected against persistent antigenemia and had significantly smaller amounts of proviral DNA and plasma viral RNA loads than PureVax recombinant FeLV-vaccinated cats and unvaccinated controls. Copyright © 2015, Patel et al.

Vector population growth and condition-dependent movement drive the spread of plant pathogens.

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Shaw, Allison K; Peace, Angela; Power, Alison G; Bosque-Pérez, Nilsa A

2017-08-01

Plant viruses, often spread by arthropod vectors, impact natural and agricultural ecosystems worldwide. Intuitively, the movement behavior and life history of vectors influence pathogen spread, but the relative contribution of each factor has not been examined. Recent research has highlighted the influence of host infection status on vector behavior and life history. Here, we developed a model to explore how vector traits influence the spread of vector-borne plant viruses. We allowed vector life history (growth rate, carrying capacity) and movement behavior (departure and settlement rates) parameters to be conditional on whether the plant host is infected or healthy and whether the vector is viruliferous (carrying the virus) or not. We ran simulations under a wide range of parameter combinations and quantified the fraction of hosts infected over time. We also ran case studies of the model for Barley yellow dwarf virus, a persistently transmitted virus, and for Potato virus Y, a non-persistently transmitted virus. We quantified the relative importance of each parameter on pathogen spread using Latin hypercube sampling with the statistical partial rank correlation coefficient technique. We found two general types of mechanisms in our model that increased the rate of pathogen spread. First, increasing factors such as vector intrinsic growth rate, carrying capacity, and departure rate from hosts (independent of whether these factors were condition-dependent) led to more vectors moving between hosts, which increased pathogen spread. Second, changing condition-dependent factors such as a vector's preference for settling on a host with a different infection status than itself, and vector tendency to leave a host of the same infection status, led to increased contact between hosts and vectors with different infection statuses, which also increased pathogen spread. Overall, our findings suggest that vector population growth rates had the greatest influence on rates of virus

Vectors of Crimean Congo Hemorrhagic Fever Virus in Iran

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Zakkyeh Telmadarraiy

2015-10-01

Full Text Available Background: Ticks are important vectors and reservoirs of Crimean Congo Hemorrhagic Fever (CCHF virus. Human beings may be infected whenever the normal life cycle of the infected ticks on non- human vertebrate hosts is interrupted by the undesirable presence of humans in the cycle. A total of 26 species of Argasid and Ixodid ticks have been recorded in Iran; including nine Hyalomma, two Rhipicephalus, two Dermacentor, five Haemaphysalis, two Boophilus, one Ixodes and two Argas as well as three Ornithodoros species as blood sucking ectoparasites of livestock and poultries. The present paper reviews tick vectors of CCHF virus in Iran, focusing on the role of ticks in different provinces of Iran using reverse transcription polymerase chain reaction (RT-PCR assay.Methods: During ten years study, 1054 tick specimens; including two species of Argasidae and 17 species of Ixodidae were examined for their infection to CCHF virus genome. The output of all studies as well as related publications were discussed in the current paper.Results: The results show that Rhipicephalus sanguineus, Hyalomma marginatum, H. anatolicum, H. asiaticum and H. dromedarii were known as the most frequent species which were positive for CCHF virus.Conclusion: The status of ticks which were positive for CCHF virus revealed that unlike the most common idea that Hyalomma species are the most important vectors of CCHF virus, other ticks including Rhipicephalus,Haemaphysalis and Dermacentor can be reservoir of this virus; thus, considering geographical distribution, type of host and environmental conditions, different tick control measurements should be carried out in areas with high incidence of CCHF disease.

Vectors of Crimean Congo Hemorrhagic Fever Virus in Iran

Science.gov (United States)

Telmadarraiy, Zakkyeh; Chinikar, Sadegh; Vatandoost, Hassan; Faghihi, Faezeh; Hosseini-Chegeni, Asadollah

2015-01-01

Background: Ticks are important vectors and reservoirs of Crimean Congo Hemorrhagic Fever (CCHF) virus. Human beings may be infected whenever the normal life cycle of the infected ticks on non-human vertebrate hosts is interrupted by the undesirable presence of humans in the cycle. A total of 26 species of Argasid and Ixodid ticks have been recorded in Iran; including nine Hyalomma, two Rhipicephalus, two Dermacentor, five Haemaphysalis, two Boophilus, one Ixodes and two Argas as well as three Ornithodoros species as blood sucking ectoparasites of livestock and poultries. The present paper reviews tick vectors of CCHF virus in Iran, focusing on the role of ticks in different provinces of Iran using reverse transcription polymerase chain reaction (RT-PCR) assay. Methods: During ten years study, 1054 tick specimens; including two species of Argasidae and 17 species of Ixodidae were examined for their infection to CCHF virus genome. The output of all studies as well as related publications were discussed in the current paper. Results: The results show that Rhipicephalus sanguineus, Hyalomma marginatum, H. anatolicum, H. asiaticum and H. dromedarii were known as the most frequent species which were positive for CCHF virus. Conclusion: The status of ticks which were positive for CCHF virus revealed that unlike the most common idea that Hyalomma species are the most important vectors of CCHF virus, other ticks including Rhipicephalus, Haemaphysalis and Dermacentor can be reservoir of this virus; thus, considering geographical distribution, type of host and environmental conditions, different tick control measurements should be carried out in areas with high incidence of CCHF disease. PMID:26623426

Plant Virus–Insect Vector Interactions: Current and Potential Future Research Directions

Science.gov (United States)

Dietzgen, Ralf G.; Mann, Krin S.; Johnson, Karyn N.

2016-01-01

Acquisition and transmission by an insect vector is central to the infection cycle of the majority of plant pathogenic viruses. Plant viruses can interact with their insect host in a variety of ways including both non-persistent and circulative transmission; in some cases, the latter involves virus replication in cells of the insect host. Replicating viruses can also elicit both innate and specific defense responses in the insect host. A consistent feature is that the interaction of the virus with its insect host/vector requires specific molecular interactions between virus and host, commonly via proteins. Understanding the interactions between plant viruses and their insect host can underpin approaches to protect plants from infection by interfering with virus uptake and transmission. Here, we provide a perspective focused on identifying novel approaches and research directions to facilitate control of plant viruses by better understanding and targeting virus–insect molecular interactions. We also draw parallels with molecular interactions in insect vectors of animal viruses, and consider technical advances for their control that may be more broadly applicable to plant virus vectors. PMID:27834855

Culicoides-virus interactions: infection barriers and possible factors underlying vector competence

Science.gov (United States)

In the United States, Culicoides midges vector arboviruses of economic importance such as Bluetongue Virus and Epizootic Hemorrhagic Disease Virus. A limited number of studies have demonstrated the complexities of midge-virus interactions, including dynamic changes in virus titer and prevalence over...

A novel method for transmitting southern rice black-streaked dwarf virus to rice without insect vector.

Science.gov (United States)

Yu, Lu; Shi, Jing; Cao, Lianlian; Zhang, Guoping; Wang, Wenli; Hu, Deyu; Song, Baoan

2017-08-15

Southern rice black-streaked dwarf virus (SRBSDV) has spread from the south of China to the north of Vietnam in the past few years, and has severely influenced rice production. However, previous study of traditional SRBSDV transmission method by the natural virus vector, the white-backed planthopper (WBPH, Sogatella furcifera), in the laboratory, researchers are frequently confronted with lack of enough viral samples due to the limited life span of infected vectors and rice plants and low virus acquisition and inoculation efficiency by the vector. Meanwhile, traditional mechanical inoculation of virus only apply to dicotyledon because of the higher content of lignin in the leaves of the monocot. Therefore, establishing an efficient and persistent-transmitting model, with a shorter virus transmission time and a higher virus transmission efficiency, for screening novel anti-SRBSDV drugs is an urgent need. In this study, we firstly reported a novel method for transmitting SRBSDV in rice using the bud-cutting method. The transmission efficiency of SRBSDV in rice was investigated via the polymerase chain reaction (PCR) method and the replication of SRBSDV in rice was also investigated via the proteomics analysis. Rice infected with SRBSDV using the bud-cutting method exhibited similar symptoms to those infected by the WBPH, and the transmission efficiency (>80.00%), which was determined using the PCR method, and the virus transmission time (30 min) were superior to those achieved that transmitted by the WBPH. Proteomics analysis confirmed that SRBSDV P1, P2, P3, P4, P5-1, P5-2, P6, P8, P9-1, P9-2, and P10 proteins were present in infected rice seedlings infected via the bud-cutting method. The results showed that SRBSDV could be successfully transmitted via the bud-cutting method and plants infected SRBSDV exhibited the symptoms were similar to those transmitted by the WBPH. Therefore, the use of the bud-cutting method to generate a cheap, efficient, reliable supply of

Viral Interference and Persistence in Mosquito-Borne Flaviviruses

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Juan Santiago Salas-Benito

2015-01-01

Full Text Available Mosquito-borne flaviviruses are important pathogens for humans, and the detection of two or more flaviviruses cocirculating in the same geographic area has often been reported. However, the epidemiological impact remains to be determined. Mosquito-borne flaviviruses are primarily transmitted through Aedes and Culex mosquitoes; these viruses establish a life-long or persistent infection without apparent pathological effects. This establishment requires a balance between virus replication and the antiviral host response. Viral interference is a phenomenon whereby one virus inhibits the replication of other viruses, and this condition is frequently associated with persistent infections. Viral interference and persistent infection are determined by several factors, such as defective interfering particles, competition for cellular factors required for translation/replication, and the host antiviral response. The interaction between two flaviviruses typically results in viral interference, indicating that these viruses share common features during the replicative cycle in the vector. The potential mechanisms involved in these processes are reviewed here.

Vector competence of Anopheles and Culex mosquitoes for Zika virus

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Brittany L. Dodson

2017-03-01

Full Text Available Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

Ability of herpes simplex virus vectors to boost immune responses to DNA vectors and to protect against challenge by simian immunodeficiency virus

International Nuclear Information System (INIS)

Kaur, Amitinder; Sanford, Hannah B.; Garry, Deirdre; Lang, Sabine; Klumpp, Sherry A.; Watanabe, Daisuke; Bronson, Roderick T.; Lifson, Jeffrey D.; Rosati, Margherita; Pavlakis, George N.; Felber, Barbara K.; Knipe, David M.; Desrosiers, Ronald C.

2007-01-01

The immunogenicity and protective capacity of replication-defective herpes simplex virus (HSV) vector-based vaccines were examined in rhesus macaques. Three macaques were inoculated with recombinant HSV vectors expressing Gag, Env, and a Tat-Rev-Nef fusion protein of simian immunodeficiency virus (SIV). Three other macaques were primed with recombinant DNA vectors expressing Gag, Env, and a Pol-Tat-Nef-Vif fusion protein prior to boosting with the HSV vectors. Robust anti-Gag and anti-Env cellular responses were detected in all six macaques. Following intravenous challenge with wild-type, cloned SIV239, peak and 12-week plasma viremia levels were significantly lower in vaccinated compared to control macaques. Plasma SIV RNA in vaccinated macaques was inversely correlated with anti-Rev ELISPOT responses on the day of challenge (P value < 0.05), anti-Tat ELISPOT responses at 2 weeks post challenge (P value < 0.05) and peak neutralizing antibody titers pre-challenge (P value 0.06). These findings support continued study of recombinant herpesviruses as a vaccine approach for AIDS

Co-occurrence of viruses and mosquitoes at the vectors' optimal climate range: An underestimated risk to temperate regions?

Science.gov (United States)

Blagrove, Marcus S C; Caminade, Cyril; Waldmann, Elisabeth; Sutton, Elizabeth R; Wardeh, Maya; Baylis, Matthew

2017-06-01

Mosquito-borne viruses have been estimated to cause over 100 million cases of human disease annually. Many methodologies have been developed to help identify areas most at risk from transmission of these viruses. However, generally, these methodologies focus predominantly on the effects of climate on either the vectors or the pathogens they spread, and do not consider the dynamic interaction between the optimal conditions for both vector and virus. Here, we use a new approach that considers the complex interplay between the optimal temperature for virus transmission, and the optimal climate for the mosquito vectors. Using published geolocated data we identified temperature and rainfall ranges in which a number of mosquito vectors have been observed to co-occur with West Nile virus, dengue virus or chikungunya virus. We then investigated whether the optimal climate for co-occurrence of vector and virus varies between "warmer" and "cooler" adapted vectors for the same virus. We found that different mosquito vectors co-occur with the same virus at different temperatures, despite significant overlap in vector temperature ranges. Specifically, we found that co-occurrence correlates with the optimal climatic conditions for the respective vector; cooler-adapted mosquitoes tend to co-occur with the same virus in cooler conditions than their warmer-adapted counterparts. We conclude that mosquitoes appear to be most able to transmit virus in the mosquitoes' optimal climate range, and hypothesise that this may be due to proportionally over-extended vector longevity, and other increased fitness attributes, within this optimal range. These results suggest that the threat posed by vector-competent mosquito species indigenous to temperate regions may have been underestimated, whilst the threat arising from invasive tropical vectors moving to cooler temperate regions may be overestimated.

Viruses vector control proposal: genus Aedes emphasis

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Nelson Nogueira Reis

2017-07-01

Full Text Available The dengue fever is a major public health problem in the world. In Brazil, in 2015, there were 1,534,932 cases, being 20,320 cases of severe form, and 811 deaths related to this disease. The distribution of Aedes aegypti, the vector, is extensive. Recently, Zika and Chikungunya viruses had arisen, sharing the same vector as dengue and became a huge public health issue. Without specific treatment, it is urgently required as an effective vector control. This article is focused on reviewing vector control strategies, their effectiveness, viability and economical impact. Among all, the Sterile Insect Technique is highlighted as the best option to be adopted in Brazil, once it is largely effectively used in the USA and Mexico for plagues related to agribusiness.

Powassan Virus: Persistence of Virus Activity During 1966

Science.gov (United States)

McLean, Donald M.; Cobb, Cathron; Gooderham, Susan E.; Smart, Carol A.; Wilson, A. G.; Wilson, W. E.

1967-01-01

Powassan virus isolations were achieved from three of 60 pools of Ixodes cookei ticks removed from 286 groundhogs (Marmota monax) which were collected some 200 miles north of Toronto between May 5 and September 5, 1966. Virus yields per pool of one to 11 ticks ranged from 102.5 to 106.0 TCD50 for primary swine kidney tissue cultures, and positive pools were collected on June 24, July 15 and August 10. Powassan neutralizing antibodies were detected by mouse inoculation tests in 143 of 362 animals including 127 of 286 groundhogs, 14 of 45 red squirrels (Tamiasciurus hudsonicus) and two of 31 other forest mammals. The monthly prevalence of antibody in the current season's groundhogs increased from 0 to 25% with the progression of summer, but in older animals the incidence remained between 38 and 62% throughout the season. These results substantiate earlier findings which pointed towards the maintenance of Powassan virus in nature by a cycle involving groundhogs and squirrels as reservoirs, with ticks as vectors, from which human infections occurred tangentially. PMID:6019677

[Streptomycin--an activator of persisting tick-borne encephalitis virus].

Science.gov (United States)

Malenko, G V; Pogodina, V V; Karmysheva, V Ia

1984-01-01

The effect of streptomycin (C) on persistence of tick-borne encephalitis (TBE) virus in Syrian hamsters infected with 3 strains of the virus (41/65, Aina/1448, Vasilchenko ) intracerebrally or subcutaneously was studied. In the animals not given C the infectious virus could be detected in the brain for 8-14 days but not later although their organs (mostly brains and spleens) contained the hemagglutinating antigen and viral antigen detectable by immunofluorescence. Intramuscularly C was given twice daily for 13-35 days in a daily dose of 200 mg/kg. The C-treated hamsters yielded 7 virulent TBE virus strains: 3 from the brain, 3 from the spleen, and one from the blood. No virus could be isolated from the liver, kidneys, or lungs despite the use of various methods for isolation including tissue explantation. The activating effect of C was observed against the background of 4-fold decrease in the titre of complement-fixing and antihemagglutinating antibodies. C exerted its activating effect both at early (70 days) and late (9 months) stages of TBE virus persistence. The activating effect of C appears to be due to its immunosuppressive properties and neurotoxic action on the CNS.

Impaired antibody response causes persistence of prototypic T cell-contained virus.

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Andreas Bergthaler

2009-04-01

Full Text Available CD8 T cells are recognized key players in control of persistent virus infections, but increasing evidence suggests that assistance from other immune mediators is also needed. Here, we investigated whether specific antibody responses contribute to control of lymphocytic choriomeningitis virus (LCMV, a prototypic mouse model of systemic persistent infection. Mice expressing transgenic B cell receptors of LCMV-unrelated specificity, and mice unable to produce soluble immunoglobulin M (IgM exhibited protracted viremia or failed to resolve LCMV. Virus control depended on immunoglobulin class switch, but neither on complement cascades nor on Fc receptor gamma chain or Fc gamma receptor IIB. Cessation of viremia concurred with the emergence of viral envelope-specific antibodies, rather than with neutralizing serum activity, and even early nonneutralizing IgM impeded viral persistence. This important role for virus-specific antibodies may be similarly underappreciated in other primarily T cell-controlled infections such as HIV and hepatitis C virus, and we suggest this contribution of antibodies be given consideration in future strategies for vaccination and immunotherapy.

Novel Strategy to Control Transgene Expression Mediated by a Sendai Virus-Based Vector Using a Nonstructural C Protein and Endogenous MicroRNAs.

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Masayuki Sano

Full Text Available Tissue-specific control of gene expression is an invaluable tool for studying various biological processes and medical applications. Efficient regulatory systems have been utilized to control transgene expression in various types of DNA viral or integrating viral vectors. However, existing regulatory systems are difficult to transfer into negative-strand RNA virus vector platforms because of significant differences in their transcriptional machineries. In this study, we developed a novel strategy for regulating transgene expression mediated by a cytoplasmic RNA vector based on a replication-defective and persistent Sendai virus (SeVdp. Because of the capacity of Sendai virus (SeV nonstructural C proteins to specifically inhibit viral RNA synthesis, overexpression of C protein significantly reduced transgene expression mediated by SeVdp vectors. We found that SeV C overexpression concomitantly reduced SeVdp mRNA levels and genomic RNA synthesis. To control C expression, target sequences for an endogenous microRNA were incorporated into the 3' untranslated region of the C genes. Incorporation of target sequences for miR-21 into the SeVdp vector restored transgene expression in HeLa cells by decreasing C expression. Furthermore, the SeVdp vector containing target sequences for let-7a enabled cell-specific control of transgene expression in human fibroblasts and induced pluripotent stem cells. Our findings demonstrate that SeV C can be used as an effective regulator for controlling transgene expression. This strategy will contribute to efficient and less toxic SeVdp-mediated gene transfer in various biological applications.

Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence

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Bialosuknia, Sean M.; Zink, Steven D.; Brecher, Matthew; Ehrbar, Dylan J.; Morrissette, Madeline N.; Kramer, Laura D.

2017-01-01

In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1–7.5 log10 PFU/mL; minimum infective dose was 4.2 log10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas. PMID:28430564

Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence.

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Ciota, Alexander T; Bialosuknia, Sean M; Zink, Steven D; Brecher, Matthew; Ehrbar, Dylan J; Morrissette, Madeline N; Kramer, Laura D

2017-07-01

In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1-7.5 log 10 PFU/mL; minimum infective dose was 4.2 log 10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas.

Vector-virus mutualism accelerates population increase of an invasive whitefly.

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Min Jiu

2007-01-01

Full Text Available The relationships between plant viruses, their herbivore vectors and host plants can be beneficial, neutral, or antagonistic, depending on the species involved. This variation in relationships may affect the process of biological invasion and the displacement of indigenous species by invaders when the invasive and indigenous organisms occur with niche overlap but differ in the interactions. The notorious invasive B biotype of the whitefly complex Bemisia tabaci entered China in the late 1990s and is now the predominant or only biotype in many regions of the country. Tobacco curly shoot virus (TbCSV and Tomato yellow leaf curl China virus (TYLCCNV are two whitefly-transmitted begomoviruses that have become widespread recently in south China. We compared the performance of the invasive B and indigenous ZHJ1 whitefly biotypes on healthy, TbCSV-infected and TYLCCNV-infected tobacco plants. Compared to its performance on healthy plants, the invasive B biotype increased its fecundity and longevity by 12 and 6 fold when feeding on TbCSV-infected plants, and by 18 and 7 fold when feeding on TYLCCNV-infected plants. Population density of the B biotype on TbCSV- and TYLCCNV-infected plants reached 2 and 13 times that on healthy plants respectively in 56 days. In contrast, the indigenous ZHJ1 performed similarly on healthy and virus-infected plants. Virus-infection status of the whiteflies per se of both biotypes showed limited effects on performance of vectors on cotton, a nonhost plant of the viruses. The indirect mutualism between the B biotype whitefly and these viruses via their host plants, and the apparent lack of such mutualism for the indigenous whitefly, may contribute to the ability of the B whitefly biotype to invade, the displacement of indigenous whiteflies, and the disease pandemics of the viruses associated with this vector.

Zika Virus RNA Replication and Persistence in Brain and Placental Tissue

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Rabeneck, Demi B.; Martines, Roosecelis B.; Reagan-Steiner, Sarah; Ermias, Yokabed; Estetter, Lindsey B.C.; Suzuki, Tadaki; Ritter, Jana; Keating, M. Kelly; Hale, Gillian; Gary, Joy; Muehlenbachs, Atis; Lambert, Amy; Lanciotti, Robert; Oduyebo, Titilope; Meaney-Delman, Dana; Bolaños, Fernando; Saad, Edgar Alberto Parra; Shieh, Wun-Ju; Zaki, Sherif R.

2017-01-01

Zika virus is causally linked with congenital microcephaly and may be associated with pregnancy loss. However, the mechanisms of Zika virus intrauterine transmission and replication and its tropism and persistence in tissues are poorly understood. We tested tissues from 52 case-patients: 8 infants with microcephaly who died and 44 women suspected of being infected with Zika virus during pregnancy. By reverse transcription PCR, tissues from 32 (62%) case-patients (brains from 8 infants with microcephaly and placental/fetal tissues from 24 women) were positive for Zika virus. In situ hybridization localized replicative Zika virus RNA in brains of 7 infants and in placentas of 9 women who had pregnancy losses during the first or second trimester. These findings demonstrate that Zika virus replicates and persists in fetal brains and placentas, providing direct evidence of its association with microcephaly. Tissue-based reverse transcription PCR extends the time frame of Zika virus detection in congenital and pregnancy-associated infections. PMID:27959260

The evolution of heart gene delivery vectors

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Wasala, Nalinda B.; Shin, Jin-Hong; Duan, Dongsheng

2012-01-01

Gene therapy holds promise for treating numerous heart diseases. A key premise for the success of cardiac gene therapy is the development of powerful gene transfer vehicles that can achieve highly efficient and persistent gene transfer specifically in the heart. Other features of an ideal vector include negligible toxicity, minimal immunogenicity and easy manufacturing. Rapid progress in the fields of molecular biology and virology has offered great opportunities to engineer various genetic materials for heart gene delivery. Several nonviral vectors (e.g. naked plasmids, plasmid lipid/polymer complexes and oligonucleotides) have been tested. Commonly used viral vectors include lentivirus, adenovirus and adeno-associated virus. Among these, adeno-associated virus has shown many attractive features for pre-clinical experimentation in animal models of heart diseases. We review the history and evolution of these vectors for heart gene transfer. PMID:21837689

Efficient gene transfer into nondividing cells by adeno-associated virus-based vectors.

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Podsakoff, G; Wong, K K; Chatterjee, S

1994-09-01

Gene transfer vectors based on adeno-associated virus (AAV) are emerging as highly promising for use in human gene therapy by virtue of their characteristics of wide host range, high transduction efficiencies, and lack of cytopathogenicity. To better define the biology of AAV-mediated gene transfer, we tested the ability of an AAV vector to efficiently introduce transgenes into nonproliferating cell populations. Cells were induced into a nonproliferative state by treatment with the DNA synthesis inhibitors fluorodeoxyuridine and aphidicolin or by contact inhibition induced by confluence and serum starvation. Cells in logarithmic growth or DNA synthesis arrest were transduced with vCWR:beta gal, an AAV-based vector encoding beta-galactosidase under Rous sarcoma virus long terminal repeat promoter control. Under each condition tested, vCWR:beta Gal expression in nondividing cells was at least equivalent to that in actively proliferating cells, suggesting that mechanisms for virus attachment, nuclear transport, virion uncoating, and perhaps some limited second-strand synthesis of AAV vectors were present in nondividing cells. Southern hybridization analysis of vector sequences from cells transduced while in DNA synthetic arrest and expanded after release of the block confirmed ultimate integration of the vector genome into cellular chromosomal DNA. These findings may provide the basis for the use of AAV-based vectors for gene transfer into quiescent cell populations such as totipotent hematopoietic stem cells.

Aedes (Stegomyia albopictus (Skuse: a potential vector of Zika virus in Singapore.

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Pei-Sze Jeslyn Wong

Full Text Available Zika virus (ZIKV is a little known arbovirus until it caused a major outbreak in the Pacific Island of Yap in 2007. Although the virus has a wide geographic distribution, most of the known vectors are sylvatic Aedes mosquitoes from Africa where the virus was first isolated. Presently, Ae. aegypti is the only known vector to transmit the virus outside the African continent, though Ae. albopictus has long been a suspected vector. Currently, Ae. albopictus has been shown capable of transmitting more than 20 arboviruses and its notoriety as an important vector came to light during the recent chikungunya pandemic. The vulnerability of Singapore to emerging infectious arboviruses has stimulated our interest to determine the competence of local Ae. albopictus to transmit ZIKV.To determine the competence of Ae. albopictus to ZIKV, we orally infected local mosquito strains to a Ugandan strain virus. Fully engorged mosquitoes were maintained in an environmental chamber set at 29°C and 80-85%RH. Twelve mosquitoes were then sampled daily from day one to seven and on day 10 and 14 post infection (pi. Zika virus titre in the midgut and salivary glands of each mosquito were determined using tissue culture infectious dose50 assay, while transmissibility of the virus was determined by detecting viral antigen in the mosquito saliva by qRT-PCR. High dissemination and transmission rate of ZIKV were observed. By day 7-pi, all mosquitoes have disseminated infection and 73% of these mosquitoes have ZIKV in their saliva. By day 10-pi, all mosquitoes were potentially infectious.The study highlighted the potential of Ae. albopictus to transmit ZIKV and the possibility that the virus could be established locally. Nonetheless, the threat of ZIKV can be mitigated by existing dengue and chikungunya control program being implemented in Singapore.

Differential profiles of direct and indirect modification of vector feeding behaviour by a plant virus.

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He, Wen-Bo; Li, Jie; Liu, Shu-Sheng

2015-01-08

Plant viruses interact with their insect vectors directly and indirectly via host plants, and this tripartite interaction may produce fitness benefits to both the vectors and the viruses. Our previous studies show that the Middle East-Asia Minor 1 (MEAM1) species of the whitefly Bemisia tabaci complex improved its performance on tobacco plants infected by the Tomato yellow leaf curl China virus (TYLCCNV), which it transmits, although virus infection of the whitefly per se reduced its performance. Here, we use electrical penetration graph recording to investigate the direct and indirect effects of TYLCCNV on the feeding behaviour of MEAM1. When feeding on either cotton, a non-host of TYLCCNV, or uninfected tobacco, a host of TYLCCNV, virus-infection of the whiteflies impeded their feeding. Interestingly, when viruliferous whiteflies fed on virus-infected tobacco, their feeding activities were no longer negatively affected; instead, the virus promoted whitefly behaviour related to rapid and effective sap ingestion. Our findings show differential profiles of direct and indirect modification of vector feeding behaviour by a plant virus, and help to unravel the behavioural mechanisms underlying a mutualistic relationship between an insect vector and a plant virus that also has features reminiscent of an insect pathogen.

A cryptic promoter in potato virus X vector interrupted plasmid construction

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Schultz Ronald D

2007-03-01

Full Text Available Abstract Background Potato virus X has been developed into an expression vector for plants. It is widely used to express foreign genes. In molecular manipulation, the foreign genes need to be sub-cloned into the vector. The constructed plasmid needs to be amplified. Usually, during amplification stage, the foreign genes are not expressed. However, if the foreign gene is expressed, the construction work could be interrupted. Two different viral genes were sub-cloned into the vector, but only one foreign gene was successfully sub-cloned. The other foreign gene, canine parvovirus type 2 (CPV-2 VP1 could not be sub-cloned into the vector and amplified without mutation (frame shift mutation. Results A cryptic promoter in the PVX vector was discovered with RT-PCR. The promoter activity was studied with Northern blots and Real-time RT-PCR. Conclusion It is important to recognize the homologous promoter sequences in the vector when a virus is developed as an expression vector. During the plasmid amplification stage, an unexpected expression of the CPV-2 VP1 gene (not in the target plants, but in E. coli can interrupt the downstream work.

Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China

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Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun

2017-01-01

In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies. PMID:28430562

Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China.

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Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun; Chen, Xiao-Guang

2017-07-01

In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies.

Persistence of canine distemper virus in the Greater Yellowstone Ecosystem's carnivore community

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Almberg, E.S.; Cross, P.C.; Smith, D.W.

2010-01-01

Canine distemper virus (CDV) is an acute, highly immunizing pathogen that should require high densities and large populations of hosts for long-term persistence, yet CDV persists among terrestrial carnivores with small, patchily distributed groups. We used CDV in the Greater Yellowstone ecosystem's (GYE) wolves (Canis lupus) and coyotes (Canis latrans) as a case study for exploring how metapopulation structure, host demographics, and multi-host transmission affect the critical community size and spatial scale required for CDV persistence. We illustrate how host spatial connectivity and demographic turnover interact to affect both local epidemic dynamics, such as the length and variation in inter-epidemic periods, and pathogen persistence using stochastic, spatially explicit susceptible-exposed-infectious-recovered simulation models. Given the apparent absence of other known persistence mechanisms (e.g., a carrier or environmental state, densely populated host, chronic infection, or a vector), we suggest that CDV requires either large spatial scales or multi-host transmission for persistence. Current GYE wolf populations are probably too small to support endemic CDV. Coyotes are a plausible reservoir host, but CDV would still require 50 000-100 000 individuals for moderate persistence (>50% over 10 years), which would equate to an area of 1-3 times the size of the GYE (60000-200000 km2). Coyotes, and carnivores in general, are not uniformly distributed; therefore, this is probably a gross underestimate of the spatial scale of CDV persistence. However, the presence of a second competent host species can greatly increase the probability of long-term CDV persistence at much smaller spatial scales. Although no management of CDV is currently recommended for the GYE, wolf managers in the region should expect periodic but unpredictable CDV-related population declines as often as every 2-5 years. Awareness and monitoring of such outbreaks will allow corresponding

Persistence of canine distemper virus in the Greater Yellowstone ecosystem's carnivore community.

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Almberg, Emily S; Cross, Paul C; Smith, Douglas W

2010-10-01

Canine distemper virus (CDV) is an acute, highly immunizing pathogen that should require high densities and large populations of hosts for long-term persistence, yet CDV persists among terrestrial carnivores with small, patchily distributed groups. We used CDV in the Greater Yellowstone ecosystem's (GYE) wolves (Canis lupus) and coyotes (Canis latrans) as a case study for exploring how metapopulation structure, host demographics, and multi-host transmission affect the critical community size and spatial scale required for CDV persistence. We illustrate how host spatial connectivity and demographic turnover interact to affect both local epidemic dynamics, such as the length and variation in inter-epidemic periods, and pathogen persistence using stochastic, spatially explicit susceptible-exposed-infectious-recovered simulation models. Given the apparent absence of other known persistence mechanisms (e.g., a carrier or environmental state, densely populated host, chronic infection, or a vector), we suggest that CDV requires either large spatial scales or multi-host transmission for persistence. Current GYE wolf populations are probably too small to support endemic CDV. Coyotes are a plausible reservoir host, but CDV would still require 50000-100000 individuals for moderate persistence (> 50% over 10 years), which would equate to an area of 1-3 times the size of the GYE (60000-200000 km2). Coyotes, and carnivores in general, are not uniformly distributed; therefore, this is probably a gross underestimate of the spatial scale of CDV persistence. However, the presence of a second competent host species can greatly increase the probability of long-term CDV persistence at much smaller spatial scales. Although no management of CDV is currently recommended for the GYE, wolf managers in the region should expect periodic but unpredictable CDV-related population declines as often as every 2-5 years. Awareness and monitoring of such outbreaks will allow corresponding adjustments

Herpes simplex virus type 1 (HSV-1)-derived recombinant vectors for gene transfer and gene therapy.

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Marconi, Peggy; Fraefel, Cornel; Epstein, Alberto L

2015-01-01

Herpes simplex virus type 1 (HSV-1 ) is a human pathogen whose lifestyle is based on a long-term dual interaction with the infected host, being able to establish both lytic and latent infections. The virus genome is a 153-kilobase pair (kbp) double-stranded DNA molecule encoding more than 80 genes. The interest of HSV-1 as gene transfer vector stems from its ability to infect many different cell types, both quiescent and proliferating cells, the very high packaging capacity of the virus capsid, the outstanding neurotropic adaptations that this virus has evolved, and the fact that it never integrates into the cellular chromosomes, thus avoiding the risk of insertional mutagenesis. Two types of vectors can be derived from HSV-1, recombinant vectors and amplicon vectors, and different methodologies have been developed to prepare large stocks of each type of vector. This chapter summarizes the approach most commonly used to prepare recombinant HSV-1 vectors through homologous recombination, either in eukaryotic cells or in bacteria.

Vector Competence of American Mosquitoes for Three Strains of Zika Virus.

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James Weger-Lucarelli

2016-10-01

Full Text Available In 2015, Zika virus (ZIKV; Flaviviridae; Flavivirus emerged in the Americas, causing millions of infections in dozens of countries. The rapid spread of the virus and the association with disease outcomes such as Guillain-Barré syndrome and microcephaly make understanding transmission dynamics essential. Currently, there are no reports of vector competence (VC of American mosquitoes for ZIKV isolates from the Americas. Further, it is not clear whether ZIKV strains from other genetic lineages can be transmitted by American Aedes aegypti populations, and whether the scope of the current epidemic is in part facilitated by viral factors such as enhanced replicative fitness or increased vector competence. Therefore, we characterized replication of three ZIKV strains, one from each of the three phylogenetic clades in several cell lines and assessed their abilities to be transmitted by Ae. aegypti mosquitoes. Additionally, laboratory colonies of different Culex spp. were infected with an American outbreak strain of ZIKV to assess VC. Replication rates were variable and depended on virus strain, cell line and MOI. African strains used in this study outcompeted the American strain in vitro in both mammalian and mosquito cell culture. West and East African strains of ZIKV tested here were more efficiently transmitted by Ae. aegypti from Mexico than was the currently circulating American strain of the Asian lineage. Long-established laboratory colonies of Culex mosquitoes were not efficient ZIKV vectors. These data demonstrate the capacity for additional ZIKV strains to infect and replicate in American Aedes mosquitoes and suggest that neither enhanced virus replicative fitness nor virus adaptation to local vector mosquitoes seems likely to explain the extent and intensity of ZIKV transmission in the Americas.

Heterologous prime-boost immunization of Newcastle disease virus vectored vaccines protected broiler chickens against highly pathogenic avian influenza and Newcastle disease viruses.

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Kim, Shin-Hee; Samal, Siba K

2017-07-24

Avian Influenza virus (AIV) is an important pathogen for both human and animal health. There is a great need to develop a safe and effective vaccine for AI infections in the field. Live-attenuated Newcastle disease virus (NDV) vectored AI vaccines have shown to be effective, but preexisting antibodies to the vaccine vector can affect the protective efficacy of the vaccine in the field. To improve the efficacy of AI vaccine, we generated a novel vectored vaccine by using a chimeric NDV vector that is serologically distant from NDV. In this study, the protective efficacy of our vaccines was evaluated by using H5N1 highly pathogenic avian influenza virus (HPAIV) strain A/Vietnam/1203/2004, a prototype strain for vaccine development. The vaccine viruses were three chimeric NDVs expressing the hemagglutinin (HA) protein in combination with the neuraminidase (NA) protein, matrix 1 protein, or nonstructural 1 protein. Comparison of their protective efficacy between a single and prime-boost immunizations indicated that prime immunization of 1-day-old SPF chicks with our vaccine viruses followed by boosting with the conventional NDV vector strain LaSota expressing the HA protein provided complete protection of chickens against mortality, clinical signs and virus shedding. Further verification of our heterologous prime-boost immunization using commercial broiler chickens suggested that a sequential immunization of chickens with chimeric NDV vector expressing the HA and NA proteins following the boost with NDV vector expressing the HA protein can be a promising strategy for the field vaccination against HPAIVs and against highly virulent NDVs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Viral (hepatitis C virus, hepatitis B virus, HIV) persistence and immune homeostasis

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Zhou, Yun; Zhang, Ying; Moorman, Jonathan P; Yao, Zhi Q; Jia, Zhan S

2014-01-01

Immune homeostasis is a host characteristic that maintains biological balance within a host. Humans have evolved many host defence mechanisms that ensure the survival of individuals upon encountering a pathogenic infection, with recovery or persistence from a viral infection being determined by both viral factors and host immunity. Chronic viral infections, such as hepatitis B virus, hepatitis C virus and HIV, often result in chronic fluctuating viraemia in the face of host cellular and humoral immune responses, which are dysregulated by multi-faceted mechanisms that are incompletely understood. This review attempts to illuminate the mechanisms involved in this process, focusing on immune homeostasis in the setting of persistent viral infection from the aspects of host defence mechanism, including interferon-stimulated genes, apolipoprotein B mRNA editing enzyme catalytic polypeptide 3 (APOBEC3), autophagy and interactions of various immune cells, cytokines and regulatory molecules. PMID:24965611

Use of insecticide-treated house screens to reduce infestations of dengue virus vectors, Mexico.

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Manrique-Saide, Pablo; Che-Mendoza, Azael; Barrera-Perez, Mario; Guillermo-May, Guillermo; Herrera-Bojorquez, Josue; Dzul-Manzanilla, Felipe; Gutierrez-Castro, Cipriano; Lenhart, Audrey; Vazquez-Prokopec, Gonzalo; Sommerfeld, Johannes; McCall, Philip J; Kroeger, Axel; Arredondo-Jimenez, Juan I

2015-02-01

Dengue prevention efforts rely on control of virus vectors. We investigated use of insecticide-treated screens permanently affixed to windows and doors in Mexico and found that the screens significantly reduced infestations of Aedes aegypti mosquitoes in treated houses. Our findings demonstrate the value of this method for dengue virus vector control.

Glycoprotein is enough for sindbis virus-derived DNA vector to express heterogenous genes

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Fu Juanjuan

2011-07-01

Full Text Available Abstract To investigate the necessity and potential application of structural genes for expressing heterogenous genes from Sindbis virus-derived vector, the DNA-based expression vector pVaXJ was constructed by placing the recombinant genome of sindbis-like virus XJ-160 under the control of the human cytomegalovirus (CMV promoter of the plasmid pVAX1, in which viral structural genes were replaced by a polylinker cassette to allow for insertion of heterologous genes. The defect helper plasmids pVaE or pVaC were developed by cloning the gene of glycoprotein E3E26KE1 or capsid protein of XJ-160 virus into pVAX1, respectively. The report gene cassette pVaXJ-EGFP or pV-Gluc expressing enhanced green fluorescence protein (EGFP or Gaussia luciferase (G.luc were constructed by cloning EGFP or G.luc gene into pVaXJ. EGFP or G.luc was expressed in the BHK-21 cells co-transfected with report gene cassettes and pVaE at levels that were comparable to those produced by report gene cassettes, pVaC and pVaE and were much higher than the levels produced by report gene cassette and pVaC, suggesting that glycoprotein is enough for Sindbis virus-derived DNA vector to express heterogenous genes in host cells. The method of gene expression from Sindbis virus-based DNA vector only co-transfected with envelop E gene increase the conveniency and the utility of alphavirus-based vector systems in general.

Saffold Virus Type 3 (SAFV-3) Persists in HeLa Cells

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Himeda, Toshiki; Hosomi, Takushi; Okuwa, Takako; Muraki, Yasushi; Ohara, Yoshiro

2013-01-01

Saffold virus (SAFV) was identified as a human cardiovirus in 2007. Although several epidemiological studies have been reported, they have failed to provide a clear picture of the relationship between SAFV and human diseases. SAFV genotype 3 has been isolated from the cerebrospinal fluid specimen of patient with aseptic meningitis. This finding is of interest since Theiler’s murine encephalomyelitis virus (TMEV), which is the closely related virus, is known to cause a multiple sclerosis-like syndrome in mice. TMEV persistently infects in mouse macrophage cells in vivo and in vitro, and the viral persistence is essential in TMEV-induced demyelinating disease. The precise mechanism(s) of SAFV infection still remain unclear. In order to clarify the SAFV pathogenicity, in the present study, we studied the possibilities of the in vitro persistent infection of SAFV. The two distinct phenotypes of HeLa cells, HeLa-N and HeLa-R, were identified. In these cells, the type of SAFV-3 infection was clearly different. HeLa-N cells were lyticly infected with SAFV-3 and the host suitable for the efficient growth. On the other hand, HeLa-R cells were persistently infected with SAFV-3. In addition, the SAFV persistence in HeLa-R cells is independent of type I IFN response of host cells although the TMEV persistence in mouse macrophage cells depends on the response. Furthermore, it was suggested that SAFV persistence may be influenced by the expression of receptor(s) for SAFV infection on the host cells. The present findings on SAFV persistence will provide the important information to encourage the research of SAFV pathogenicity. PMID:23308162

Virus-induced gene silencing in diverse maize lines using the Brome Mosaic virus-based silencing vector

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Virus-induced gene silencing (VIGS) is a widely used tool for gene function studies in many plant species, though its use in monocots has been limited. Using a Brome mosaic virus (BMV) vector designed to silence the maize phytoene desaturase gene, a genetically diverse set of maize inbred lines was ...

Migration and persistence of human influenza A viruses, Vietnam, 2001-2008.

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Le, Mai Quynh; Lam, Ha Minh; Cuong, Vuong Duc; Lam, Tommy Tsan-Yuk; Halpin, Rebecca A; Wentworth, David E; Hien, Nguyen Tran; Thanh, Le Thi; Phuong, Hoang Vu Mai; Horby, Peter; Boni, Maciej F

2013-11-01

Understanding global influenza migration and persistence is crucial for vaccine strain selection. Using 240 new human influenza A virus whole genomes collected in Vietnam during 2001-2008, we looked for persistence patterns and migratory connections between Vietnam and other countries. We found that viruses in Vietnam migrate to and from China, Hong Kong, Taiwan, Cambodia, Japan, South Korea, and the United States. We attempted to reduce geographic bias by generating phylogenies subsampled at the year and country levels. However, migration events in these phylogenies were still driven by the presence or absence of sequence data, indicating that an epidemiologic study design that controls for prevalence is required for robust migration analysis. With whole-genome data, most migration events are not detectable from the phylogeny of the hemagglutinin segment alone, although general migratory relationships between Vietnam and other countries are visible in the hemagglutinin phylogeny. It is possible that virus lineages in Vietnam persisted for >1 year.

Oncolytic Herpes Simplex Virus Vectors Fully Retargeted to Tumor- Associated Antigens.

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Uchida, Hiroaki; Hamada, Hirofumi; Nakano, Kenji; Kwon, Heechung; Tahara, Hideaki; Cohen, Justus B; Glorioso, Joseph C

2018-01-01

Oncolytic virotherapy is a novel therapeutic modality for malignant diseases that exploits selective viral replication in cancer cells. Herpes simplex virus (HSV) is a promising agent for oncolytic virotherapy due to its broad cell tropism and the identification of mutations that favor its replication in tumor over normal cells. However, these attenuating mutations also tend to limit the potency of current oncolytic HSV vectors that have entered clinical studies. As an alternative, vector retargeting to novel entry receptors has the potential to achieve tumor specificity at the stage of virus entry, eliminating the need for replication-attenuating mutations. Here, we summarize the molecular mechanism of HSV entry and recent advances in the development of fully retargeted HSV vectors for oncolytic virotherapy. Retargeted HSV vectors offer an attractive platform for the creation of a new generation of oncolytic HSV with improved efficacy and specificity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Torradoviruses are transmitted in a semi-persistent and stylet-borne manner by three whitefly vectors

NARCIS (Netherlands)

Verbeek, M.; Bekkum, van P.J.; Dullemans, A.M.; Vlugt, van der R.A.A.

2014-01-01

Members of the genus Torradovirus (family Secoviridae, type species Tomato torrado virus, ToTV) are spherical plant viruses transmitted by the whitefly species Trialeurodes vaporariorum and Bemisia tabaci. Knowledge on the mode of vector transmission is lacking for torradoviruses. Here, the mode of

Vectores recombinantes basados en el virus Vaccinia modificado de Ankara (MVA) como vacunas contra la leishmaniasis

OpenAIRE

Pérez Jiménez, Eva; Larraga, Vicente; Esteban, Mariano

2005-01-01

Vectores recombinantes basados en el virus vaccinia modificado de Ankara (MVA) como vacunas contra la leishmaniasis. Los vectores de la invención contienen secuencias codificantes de la proteína LACK, preferentemente insertadas en el locus de hemaglutinina del virus y bajo el control de un promotor que permite su expresión a lo largo del ciclo de infección del virus. Son vectores seguros, estables, que dan lugar a una potente respuesta inmune que confiere protección frente a la leishmaniasis,...

Hepatitis E virus persists in the presence of a type III interferon response.

Science.gov (United States)

Yin, Xin; Li, Xinlei; Ambardekar, Charuta; Hu, Zhimin; Lhomme, Sébastien; Feng, Zongdi

2017-05-01

The RIG-I-like RNA helicase (RLR)-mediated interferon (IFN) response plays a pivotal role in the hepatic antiviral immunity. The hepatitis A virus (HAV) and the hepatitis C virus (HCV) counter this response by encoding a viral protease that cleaves the mitochondria antiviral signaling protein (MAVS), a common signaling adaptor for RLRs. However, a third hepatotropic RNA virus, the hepatitis E virus (HEV), does not appear to encode a functional protease yet persists in infected cells. We investigated HEV-induced IFN responses in human hepatoma cells and primary human hepatocytes. HEV infection resulted in persistent virus replication despite poor spread. This was companied by a type III IFN response that upregulated multiple IFN-stimulated genes (ISGs), but type I IFNs were barely detected. Blocking type III IFN production or signaling resulted in reduced ISG expression and enhanced HEV replication. Unlike HAV and HCV, HEV did not cleave MAVS; MAVS protein size, mitochondrial localization, and function remained unaltered in HEV-replicating cells. Depletion of MAVS or MDA5, and to a less extent RIG-I, also diminished IFN production and increased HEV replication. Furthermore, persistent activation of the JAK/STAT signaling rendered infected cells refractory to exogenous IFN treatment, and depletion of MAVS or the receptor for type III IFNs restored the IFN responsiveness. Collectively, these results indicate that unlike other hepatotropic RNA viruses, HEV does not target MAVS and its persistence is associated with continuous production of type III IFNs.

Comparison of Detection of Bovine Virus Diarrhea Virus Antigen in Various Types of Tissue and Fluid Samples Collected from Persistently Infected Cattle

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Bovine viral diarrhea viruses are economically important pathogens of cattle. Most new infections are acquired from animals persistently infected with the virus. Surveillance programs rely on skin biopsies for detection of persistently infected cattle. The purpose of this study was to compare ant...

Postnatal persistent infection with classical Swine Fever virus and its immunological implications.

Directory of Open Access Journals (Sweden)

Sara Muñoz-González

Full Text Available It is well established that trans-placental transmission of classical swine fever virus (CSFV during mid-gestation can lead to persistently infected offspring. The aim of the present study was to evaluate the ability of CSFV to induce viral persistence upon early postnatal infection. Two litters of 10 piglets each were infected intranasally on the day of birth with low and moderate virulence CSFV isolates, respectively. During six weeks after postnatal infection, most of the piglets remained clinically healthy, despite persistent high virus titres in the serum. Importantly, these animals were unable to mount any detectable humoral and cellular immune response. At necropsy, the most prominent gross pathological lesion was a severe thymus atrophy. Four weeks after infection, PBMCs from the persistently infected seronegative piglets were unresponsive to both, specific CSFV and non-specific PHA stimulation in terms of IFN-γ-producing cells. These results suggested the development of a state of immunosuppression in these postnatally persistently infected pigs. However, IL-10 was undetectable in the sera of the persistently infected animals. Interestingly, CSFV-stimulated PBMCs from the persistently infected piglets produced IL-10. Nevertheless, despite the addition of the anti-IL-10 antibody in the PBMC culture from persistently infected piglets, the response of the IFN-γ producing cells was not restored. Therefore, other factors than IL-10 may be involved in the general suppression of the T-cell responses upon CSFV and mitogen activation. Interestingly, bone marrow immature granulocytes were increased and targeted by the virus in persistently infected piglets. Taken together, we provided the first data demonstrating the feasibility of CSFV in generating a postnatal persistent disease, which has not been shown for other members of the Pestivirus genus yet. Since serological methods are routinely used in CSFV surveillance, persistently infected pigs

Proteomic Analysis of Interaction between a Plant Virus and Its Vector Insect Reveals New Functions of Hemipteran Cuticular Protein.

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Liu, Wenwen; Gray, Stewart; Huo, Yan; Li, Li; Wei, Taiyun; Wang, Xifeng

2015-08-01

Numerous viruses can be transmitted by their corresponding vector insects; however, the molecular mechanisms enabling virus transmission by vector insects have been poorly understood, especially the identity of vector components interacting with the virus. Here, we used the yeast two-hybrid system to study proteomic interactions of a plant virus (Rice stripe virus, RSV, genus Tenuivirus) with its vector insect, small brown planthopper (Laodelphax striatellus). Sixty-six proteins of L. striatellus that interacted with the nucleocapsid protein (pc3) of RSV were identified. A virus-insect interaction network, constructed for pc3 and 29 protein homologs of Drosophila melanogaster, suggested that nine proteins might directly interact with pc3. Of the 66 proteins, five (atlasin, a novel cuticular protein, jagunal, NAC domain protein, and vitellogenin) were most likely to be involved in viral movement, replication, and transovarial transmission. This work also provides evidence that the novel cuticular protein, CPR1, from L. striatellus is essential for RSV transmission by its vector insect. CPR1 binds the nucleocapsid protein (pc3) of RSV both in vivo and in vitro and colocalizes with RSV in the hemocytes of L. striatellus. Knockdown of CPR1 transcription using RNA interference resulted in a decrease in the concentration of RSV in the hemolymph, salivary glands and in viral transmission efficiency. These data suggest that CPR1 binds RSV in the insect and stabilizes the viral concentration in the hemolymph, perhaps to protect the virus or to help move the virus to the salivary tissues. Our studies provide direct experimental evidence that viruses can use existing vector proteins to aid their survival in the hemolymph. Identifying these putative vector molecules should lead to a better understanding of the interactions between viruses and vector insects. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Potential Sympatric Vectors and Mammalian Hosts of Venezuelan Equine Encephalitis Virus in Southern Mexico.

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Sotomayor-Bonilla, Jesús; Abella-Medrano, Carlos Antonio; Chaves, Andrea; Álvarez-Mendizábal, Paulina; Rico-Chávez, Óscar; Ibáñez-Bernal, Sergio; Rostal, Melinda K; Ojeda-Flores, Rafael; Barbachano-Guerrero, Arturo; Gutiérrez-Espeleta, Gustavo; Aguirre, A Alonso; Daszak, Peter; Suzán, Gerardo

2017-07-01

Arboviruses are important zoonotic agents with complex transmission cycles and are not well understood because they may involve many vectors and hosts. We studied sympatric wild mammals and hematophagous mosquitoes having the potential to act as hosts and vectors in two areas of southern Mexico. Mosquitoes, bats, and rodents were captured in Calakmul (Campeche) and Montes Azules (Chiapas), between November 2010 and August 2011. Spleen samples from 146 bats and 14 rodents were tested for molecular evidence of Venezuelan equine encephalitis virus (VEEV), eastern equine encephalitis virus (EEEV), western equine encephalitis virus (WEEV), and West Nile virus (WNV) using PCR protocols. Bat ( Artibeus lituratus , Carollia sowelli , Glossophaga soricina , and Sturnira parvidens) and rodent ( Sigmodon hispidus and Oryzomys alfaroi ) species were positive for VEEV. No individuals were positive for WNV, EEEV, or WEEV. A total of 1,298 mosquitoes were collected at the same sites, and five of the mosquito species collected were known VEEV vectors (Aedes fulvus, Mansonia indubitans, Psorophora ferox, Psorophora cilipes, and Psorophora confinnis). This survey simultaneously presents the first molecular evidence, to our knowledge, of VEEV in bats and rodents from southern Mexico and the identification of potential sympatric vectors. Studies investigating sympatric nonhuman hosts, vectors, and arboviruses must be expanded to determine arboviral dynamics in complex systems in which outbreaks of emerging and reemerging zoonoses are continuously occurring.

Environmental and biological factors influencing Culex pipiens quinquefasciatus (Diptera: Culicidae) vector competence for West Nile Virus.

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Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra N; Tabachnick, Walter J

2010-07-01

Interactions between environmental and biological factors affect the vector competence of Culex pipiens quinquefasciatus for West Nile virus. Three age cohorts from two Cx. p. quinquefasciatus colonies were fed blood containing a low- or high-virus dose, and each group was held at two different extrinsic incubation temperatures (EIT) for 13 days. The colonies differed in the way that they responded to the effects of the environment on vector competence. The effects of mosquito age on aspects of vector competence were dependent on the EIT and dose, and they changed depending on the colony. Complex interactions must be considered in laboratory studies of vector competence, because the extent of the genetic and environmental variation controlling vector competence in nature is largely unknown. Differences in the environmental (EIT and dose) and biological (mosquito age and colony) effects from previous studies of Cx. p. quinquefasciatus vector competence for St. Louis encephalitis virus are discussed.

Expression of the Surface Glycoproteins of Human Parainfluenza Virus Type 3 by Bovine Parainfluenza Virus Type 3, a Novel Attenuated Virus Vaccine Vector

OpenAIRE

Haller, Aurelia A.; Miller, Tessa; Mitiku, Misrach; Coelingh, Kathleen

2000-01-01

Bovine parainfluenza virus type 3 (bPIV3) is being evaluated as an intranasal vaccine for protection against human PIV3 (hPIV3). In young infants, the bPIV3 vaccine appears to be infectious, attenuated, immunogenic, and genetically stable, which are desirable characteristics for an RNA virus vector. To test the potential of the bPIV3 vaccine strain as a vector, an infectious DNA clone of bPIV3 was assembled and recombinant bPIV3 (r-bPIV3) was rescued. r-bPIV3 displayed a temperature-sensitive...

Anterograde or Retrograde Transsynaptic Circuit Tracing in Vertebrates with Vesicular Stomatitis Virus Vectors.

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Beier, Kevin T; Mundell, Nathan A; Pan, Y Albert; Cepko, Constance L

2016-01-04

Viruses have been used as transsynaptic tracers, allowing one to map the inputs and outputs of neuronal populations, due to their ability to replicate in neurons and transmit in vivo only across synaptically connected cells. To date, their use has been largely restricted to mammals. In order to explore the use of such viruses in an expanded host range, we tested the transsynaptic tracing ability of recombinant vesicular stomatitis virus (rVSV) vectors in a variety of organisms. Successful infection and gene expression were achieved in a wide range of organisms, including vertebrate and invertebrate model organisms. Moreover, rVSV enabled transsynaptic tracing of neural circuitry in predictable directions dictated by the viral envelope glycoprotein (G), derived from either VSV or rabies virus (RABV). Anterograde and retrograde labeling, from initial infection and/or viral replication and transmission, was observed in Old and New World monkeys, seahorses, jellyfish, zebrafish, chickens, and mice. These vectors are widely applicable for gene delivery, afferent tract tracing, and/or directional connectivity mapping. Here, we detail the use of these vectors and provide protocols for propagating virus, changing the surface glycoprotein, and infecting multiple organisms using several injection strategies. Copyright © 2016 John Wiley & Sons, Inc.

Geographic range of vector-borne infections and their vectors: the role of African wildlife.

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van Vuuren, M; Penzhorn, B L

2015-04-01

The role of African wildlife in the occurrence of vector-borne infections in domestic animals has gained renewed interest as emerging and re-emerging infections occur worldwide at an increasing rate. In Africa, biodiversity conservation and the expansion of livestock production have increased the risk of transmitting vector-borne infections between wildlife and livestock. The indigenous African pathogens with transboundary potential, such as Rift Valley fever virus, African horse sickness virus, bluetongue virus, lumpy skin disease virus, African swine fever virus, and blood-borne parasites have received the most attention. There is no evidence for persistent vector-borne viral infections in African wildlife. For some viral infections, wildlife may act as a reservoir through the inter-epidemic circulation of viruses with mild or subclinical manifestations. Wildlife may also act as introductory or transporting hosts when moved to new regions, e.g. for lumpy skin disease virus, Rift Valley fever virus and West Nile virus. Wildlife may also act as amplifying hosts when exposed to viruses in the early part of the warm season when vectors are active, with spillover to domestic animals later in the season, e.g. with bluetongue and African horse sickness. Some tick species found on domestic animals are more abundant on wildlife hosts; some depend on wildlife hosts to complete their life cycle. Since the endemic stability of a disease depends on a sufficiently large tick population to ensure that domestic animals become infected at an early age, the presence of wildlife hosts that augment tick numbers may be beneficial. Many wild ungulate species are reservoirs of Anaplasma spp., while the role of wildlife in the epidemiology of heartwater (Ehrlichia ruminantium infection) has not been elucidated. Wild ungulates are not usually reservoirs of piroplasms that affect livestock; however, there are two exceptions: zebra, which are reservoirs of Babesia caballi and Theileria

Migration and Persistence of Human Influenza A Viruses, Vietnam, 2001–2008

Science.gov (United States)

Le, Mai Quynh; Lam, Ha Minh; Cuong, Vuong Duc; Lam, Tommy Tsan-Yuk; Halpin, Rebecca A; Wentworth, David E; Hien, Nguyen Tran; Thanh, Le Thi; Phuong, Hoang Vu Mai; Horby, Peter

2013-01-01

Understanding global influenza migration and persistence is crucial for vaccine strain selection. Using 240 new human influenza A virus whole genomes collected in Vietnam during 2001–2008, we looked for persistence patterns and migratory connections between Vietnam and other countries. We found that viruses in Vietnam migrate to and from China, Hong Kong, Taiwan, Cambodia, Japan, South Korea, and the United States. We attempted to reduce geographic bias by generating phylogenies subsampled at the year and country levels. However, migration events in these phylogenies were still driven by the presence or absence of sequence data, indicating that an epidemiologic study design that controls for prevalence is required for robust migration analysis. With whole-genome data, most migration events are not detectable from the phylogeny of the hemagglutinin segment alone, although general migratory relationships between Vietnam and other countries are visible in the hemagglutinin phylogeny. It is possible that virus lineages in Vietnam persisted for >1 year. PMID:24188643

Generation of a Lineage II Powassan Virus (Deer Tick Virus) cDNA Clone: Assessment of Flaviviral Genetic Determinants of Tick and Mosquito Vector Competence.

Science.gov (United States)

Kenney, Joan L; Anishchenko, Michael; Hermance, Meghan; Romo, Hannah; Chen, Ching-I; Thangamani, Saravanan; Brault, Aaron C

2018-05-21

The Flavivirus genus comprises a diverse group of viruses that utilize a wide range of vertebrate hosts and arthropod vectors. The genus includes viruses that are transmitted solely by mosquitoes or vertebrate hosts as well as viruses that alternate transmission between mosquitoes or ticks and vertebrates. Nevertheless, the viral genetic determinants that dictate these unique flaviviral host and vector specificities have been poorly characterized. In this report, a cDNA clone of a flavivirus that is transmitted between ticks and vertebrates (Powassan lineage II, deer tick virus [DTV]) was generated and chimeric viruses between the mosquito/vertebrate flavivirus, West Nile virus (WNV), were constructed. These chimeric viruses expressed the prM and E genes of either WNV or DTV in the heterologous nonstructural (NS) backbone. Recombinant chimeric viruses rescued from cDNAs were characterized for their capacity to grow in vertebrate and arthropod (mosquito and tick) cells as well as for in vivo vector competence in mosquitoes and ticks. Results demonstrated that the NS elements were insufficient to impart the complete mosquito or tick growth phenotypes of parental viruses; however, these NS genetic elements did contribute to a 100- and 100,000-fold increase in viral growth in vitro in tick and mosquito cells, respectively. Mosquito competence was observed only with parental WNV, while infection and transmission potential by ticks were observed with both DTV and WNV-prME/DTV chimeric viruses. These data indicate that NS genetic elements play a significant, but not exclusive, role for vector usage of mosquito- and tick-borne flaviviruses.

Propagation of respiratory viruses in human airway epithelia reveals persistent virus-specific signatures.

Science.gov (United States)

Essaidi-Laziosi, Manel; Brito, Francisco; Benaoudia, Sacha; Royston, Léna; Cagno, Valeria; Fernandes-Rocha, Mélanie; Piuz, Isabelle; Zdobnov, Evgeny; Huang, Song; Constant, Samuel; Boldi, Marc-Olivier; Kaiser, Laurent; Tapparel, Caroline

2018-06-01

The leading cause of acute illnesses, respiratory viruses, typically cause self-limited diseases, although severe complications can occur in fragile patients. Rhinoviruses (RVs), respiratory enteroviruses (EVs), influenza virus, respiratory syncytial viruses (RSVs), and coronaviruses are highly prevalent respiratory pathogens, but because of the lack of reliable animal models, their differential pathogenesis remains poorly characterized. We sought to compare infections by respiratory viruses isolated from clinical specimens using reconstituted human airway epithelia. Tissues were infected with RV-A55, RV-A49, RV-B48, RV-C8, and RV-C15; respiratory EV-D68; influenza virus H3N2; RSV-B; and human coronavirus (HCoV)-OC43. Replication kinetics, cell tropism, effect on tissue integrity, and cytokine secretion were compared. Viral adaptation and tissue response were assessed through RNA sequencing. RVs, RSV-B, and HCoV-OC43 infected ciliated cells and caused no major cell death, whereas H3N2 and EV-D68 induced ciliated cell loss and tissue integrity disruption. H3N2 was also detected in rare goblet and basal cells. All viruses, except RV-B48 and HCoV-OC43, altered cilia beating and mucociliary clearance. H3N2 was the strongest cytokine inducer, and HCoV-OC43 was the weakest. Persistent infection was observed in all cases. RNA sequencing highlighted perturbation of tissue metabolism and induction of a transient but important immune response at 4 days after infection. No majority mutations emerged in the viral population. Our results highlight the differential in vitro pathogenesis of respiratory viruses during the acute infection phase and their ability to persist under immune tolerance. These data help to appreciate the range of disease severity observed in vivo and the occurrence of chronic respiratory tract infections in immunocompromised hosts. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Persistent infection with ebola virus under conditions of partial immunity.

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Gupta, Manisha; Mahanty, Siddhartha; Greer, Patricia; Towner, Jonathan S; Shieh, Wun-Ju; Zaki, Sherif R; Ahmed, Rafi; Rollin, Pierre E

2004-01-01

Ebola hemorrhagic fever in humans is associated with high mortality; however, some infected hosts clear the virus and recover. The mechanisms by which this occurs and the correlates of protective immunity are not well defined. Using a mouse model, we determined the role of the immune system in clearance of and protection against Ebola virus. All CD8 T-cell-deficient mice succumbed to subcutaneous infection and had high viral antigen titers in tissues, whereas mice deficient in B cells or CD4 T cells cleared infection and survived, suggesting that CD8 T cells, independent of CD4 T cells and antibodies, are critical to protection against subcutaneous Ebola virus infection. B-cell-deficient mice that survived the primary subcutaneous infection (vaccinated mice) transiently depleted or not depleted of CD4 T cells also survived lethal intraperitoneal rechallenge for >/==" BORDER="0">25 days. However, all vaccinated B-cell-deficient mice depleted of CD8 T cells had high viral antigen titers in tissues following intraperitoneal rechallenge and died within 6 days, suggesting that memory CD8 T cells by themselves can protect mice from early death. Surprisingly, vaccinated B-cell-deficient mice, after initially clearing the infection, were found to have viral antigens in tissues later (day 120 to 150 post-intraperitoneal infection). Furthermore, following intraperitoneal rechallenge, vaccinated B-cell-deficient mice that were transiently depleted of CD4 T cells had high levels of viral antigen in tissues earlier (days 50 to 70) than vaccinated undepleted mice. This demonstrates that under certain immunodeficiency conditions, Ebola virus can persist and that loss of primed CD4 T cells accelerates the course of persistent infections. These data show that CD8 T cells play an important role in protection against acute disease, while both CD4 T cells and antibodies are required for long-term protection, and they provide evidence of persistent infection by Ebola virus suggesting

Induction and Maintenance of CX3CR1-Intermediate Peripheral Memory CD8+ T Cells by Persistent Viruses and Vaccines

Directory of Open Access Journals (Sweden)

Claire Louse Gordon

2018-04-01

Full Text Available Summary: The induction and maintenance of T cell memory is critical to the success of vaccines. A recently described subset of memory CD8+ T cells defined by intermediate expression of the chemokine receptor CX3CR1 was shown to have self-renewal, proliferative, and tissue-surveillance properties relevant to vaccine-induced memory. We tracked these cells when memory is sustained at high levels: memory inflation induced by cytomegalovirus (CMV and adenovirus-vectored vaccines. In mice, both CMV and vaccine-induced inflationary T cells showed sustained high levels of CX3R1int cells exhibiting an effector-memory phenotype, characteristic of inflationary pools, in early memory. In humans, CX3CR1int CD8+ T cells were strongly induced following adenovirus-vectored vaccination for hepatitis C virus (HCV (ChAd3-NSmut and during natural CMV infection and were associated with a memory phenotype similar to that in mice. These data indicate that CX3CR1int cells form an important component of the memory pool in response to persistent viruses and vaccines in both mice and humans. : Gordon et al. demonstrate that CX3CR1int peripheral memory T cells are a substantial component of memory inflation induced by persistent CMVs and adenoviral vaccination. They are characterized by sustained proliferation and an effector-memory phenotype linked to these expanded CD8+ T cell memory responses. Core phenotypic features are shared by humans and mice. Keywords: cytomegalovirus, T cells, memory, adenovirus, vaccination, CX3CR1, memory inflation, mouse, human

Epidemiology and integrated management of persistently transmitted aphid-borne viruses of legume and cereal crops in West Asia and North Africa.

Science.gov (United States)

Makkouk, Khaled M; Kumari, Safaa G

2009-05-01

Cool-season food legumes (faba bean, lentil, chickpea and pea) and cereals (bread and durum wheat and barley) are the most important and widely cultivated crops in West Asia and North Africa (WANA), where they are the main source of carbohydrates and protein for the majority of the population. Persistently transmitted aphid-borne viruses pose a significant limitation to legume and cereal production worldwide. Surveys conducted in many countries in WANA during the last three decades established that the most important of these viruses are: Faba bean necrotic yellows virus (FBNYV: genus Nanovirus; family Nanoviridae), Bean leafroll virus (BLRV: genus Luteovirus; family Luteoviridae), Beet western yellows virus (BWYV: genus Polerovirus; family Luteoviridae), Soybean dwarf virus (SbDV: genus Luteovirus; family Luteoviridae) and Chickpea chlorotic stunt virus (CpCSV: genus Polerovirus; family Luteoviridae) which affect legume crops, and Barley yellow dwarf virus-PAV (BYDV-PAV: genus Luteovirus; family Luteoviridae), Barley yellow dwarf virus-MAV (BYDV-MAV: genus Luteovirus; family Luteoviridae) and Cereal yellow dwarf virus-RPV (CYDV-RPV: genus Polerovirus; family Luteoviridae) which affect cereal crops. Loss in yield caused by these viruses is usually high when infection occurs early in the growing season. Many aphid vector species for the above-mentioned viruses are reported to be prevalent in the WANA region. In addition, in this region many wild species (annual or perennial) were found infected with these viruses and may play an important role in their ecology and spread. Fast spread of these diseases was always associated with high aphid vector populations and activity. Although virus disease management can be achieved by combining several control measures, development of resistant genotypes is undoubtedly one of the most appropriate control methods. Over the last three decades barley and wheat genotypes resistant to BYDV, faba bean genotypes resistant to BLRV, and

Foamy Virus Biology and Its Application for Vector Development

Directory of Open Access Journals (Sweden)

Axel Rethwilm

2011-05-01

Full Text Available Spuma- or foamy viruses (FV, endemic in most non-human primates, cats, cattle and horses, comprise a special type of retrovirus that has developed a replication strategy combining features of both retroviruses and hepadnaviruses. Unique features of FVs include an apparent apathogenicity in natural hosts as well as zoonotically infected humans, a reverse transcription of the packaged viral RNA genome late during viral replication resulting in an infectious DNA genome in released FV particles and a special particle release strategy depending capsid and glycoprotein coexpression and specific interaction between both components. In addition, particular features with respect to the integration profile into the host genomic DNA discriminate FV from orthoretroviruses. It appears that some inherent properties of FV vectors set them favorably apart from orthoretroviral vectors and ask for additional basic research on the viruses as well as on the application in Gene Therapy. This review will summarize the current knowledge of FV biology and the development as a gene transfer system.

Coevolution of a Persistent Plant Virus and Its Pepper Hosts.

Science.gov (United States)

Safari, Maliheh; Roossinck, Marilyn J

2018-05-30

There are many nonpathogenic viruses that are maintained in a persistent lifestyle in plants. Plant persistent viruses are widespread, replicating in their hosts for many generations. So far, Endornaviridae is the only family of plant persistent viruses with a single-stranded RNA genome, containing one large open reading frame. Bell pepper endornavirus (BPEV), Hot pepper endornavirus, Capsicum frutescens endornavirus 1 (CFEV 1) have been identified from peppers. Peppers are native to Central and South America and, as domesticated plants, human selection accelerated their evolution. We investigated the evolution of these endornaviruses in different peppers including Capsicum annuum, C. chacoense, C.chinense, C. frutescens, C.bacccutum, and C. pubescens using two fragments from the viral helicase (Hel) and RNA dependent RNA polymerase (RdRp) domains. In addition, using single nucleotide polymorphisms, we analyzed the pepper host populations and phylogenies. The endornaviruses phylogeny was correlated with its Capsicum species host. In this study, BPEV was limited to C. annuum species, and the RdRp and Hel phylogenies identified two clades that correlated with the host pungency. No C. annuum infected with CFEV 1 was found in this study, but the CFEV 1 RdRp fragment was recovered from C. chinense, C. frutescens, C. bacccutum, and C. pubescens. Hence, during pepper speciation, the ancestor of CFEV 1 may have evolved as a new endornavirus, BPEV, in C. annuum peppers.

No benefit of therapeutic vaccination in clinically healthy cats persistently infected with feline leukemia virus.

Science.gov (United States)

Helfer-Hungerbuehler, A Katrin; Spiri, Andrea M; Riond, Barbara; Grest, Paula; Boretti, Felicitas S; Hofmann-Lehmann, Regina

2015-03-24

Therapeutic vaccinations have a potential application in infections where no curative treatment is available. In contrast to HIV, efficacious vaccines for a cat retrovirus, feline leukemia virus (FeLV), are commercially available. However, the infection is still prevalent, and no effective treatment of the infection is known. By vaccinating persistently FeLV-infected cats and presenting FeLV antigens to the immune system of the host, e.g., in the form of recombinant and/or adjuvanted antigens, we intended to shift the balance toward an advantage of the host so that persistent infection could be overcome by the infected cat. Two commercially available FeLV vaccines efficacious in protecting naïve cats from FeLV infection were tested in six experimentally and persistently FeLV-infected cats: first, a canarypox-vectored vaccine, and second, an adjuvanted, recombinant envelope vaccine was repeatedly administered with the aim to stimulate the immune system. No beneficial effects on p27 antigen and plasma viral RNA loads, anti-FeLV antibodies, or life expectancy of the cats were detected. The cats were unable to overcome or decrease viremia. Some cats developed antibodies to FeLV antigens although not protective. Thus, we cannot recommend vaccinating persistently FeLV-infected cats as a means of improving their FeLV status, quality of life or life expectancy. We suggest testing of all cats for FeLV infection prior to FeLV vaccination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Virus infection mediates the effects of elevated CO2 on plants and vectors

Science.gov (United States)

Trębicki, Piotr; Vandegeer, Rebecca K.; Bosque-Pérez, Nilsa A.; Powell, Kevin S.; Dader, Beatriz; Freeman, Angela J.; Yen, Alan L.; Fitzgerald, Glenn J.; Luck, Jo E.

2016-03-01

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.

Spatio-Temporal Dynamics of Viruses are Differentially Affected by Parasitoids Depending on the Mode of Transmission

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Elisa Viñuela

2012-11-01

Full Text Available Relationships between agents in multitrophic systems are complex and very specific. Insect-transmitted plant viruses are completely dependent on the behaviour and distribution patterns of their vectors. The presence of natural enemies may directly affect aphid behaviour and spread of plant viruses, as the escape response of aphids might cause a potential risk for virus dispersal. The spatio-temporal dynamics of Cucumber mosaic virus (CMV and Cucurbit aphid-borne yellows virus (CABYV, transmitted by Aphis gossypii in a non-persistent and persistent manner, respectively, were evaluated at short and long term in the presence and absence of the aphid parasitoid, Aphidius colemani. SADIE methodology was used to study the distribution patterns of both the virus and its vector, and their degree of association. Results suggested that parasitoids promoted aphid dispersion at short term, which enhanced CMV spread, though consequences of parasitism suggest potential benefits for disease control at long term. Furthermore, A. colemani significantly limited the spread and incidence of the persistent virus CABYV at long term. The impact of aphid parasitoids on the dispersal of plant viruses with different transmission modes is discussed.

Development of risk reduction behavioral counseling for Ebola virus disease survivors enrolled in the Sierra Leone Ebola Virus Persistence Study, 2015-2016.

Science.gov (United States)

Abad, Neetu; Malik, Tasneem; Ariyarajah, Archchun; Ongpin, Patricia; Hogben, Matthew; McDonald, Suzanna L R; Marrinan, Jaclyn; Massaquoi, Thomas; Thorson, Anna; Ervin, Elizabeth; Bernstein, Kyle; Ross, Christine; Liu, William J; Kroeger, Karen; Durski, Kara N; Broutet, Nathalie; Knust, Barbara; Deen, Gibrilla F

2017-09-01

During the 2014-2016 West Africa Ebola Virus Disease (EVD) epidemic, the public health community had concerns that sexual transmission of the Ebola virus (EBOV) from EVD survivors was a risk, due to EBOV persistence in body fluids of EVD survivors, particularly semen. The Sierra Leone Ebola Virus Persistence Study was initiated to investigate this risk by assessing EBOV persistence in numerous body fluids of EVD survivors and providing risk reduction counseling based on test results for semen, vaginal fluid, menstrual blood, urine, rectal fluid, sweat, tears, saliva, and breast milk. This publication describes implementation of the counseling protocol and the key lessons learned. The Ebola Virus Persistence Risk Reduction Behavioral Counseling Protocol was developed from a framework used to prevent transmission of HIV and other sexually transmitted infections. The framework helped to identify barriers to risk reduction and facilitated the development of a personalized risk-reduction plan, particularly around condom use and abstinence. Pre-test and post-test counseling sessions included risk reduction guidance, and post-test counseling was based on the participants' individual test results. The behavioral counseling protocol enabled study staff to translate the study's body fluid test results into individualized information for study participants. The Ebola Virus Persistence Risk Reduction Behavioral Counseling Protocol provided guidance to mitigate the risk of EBOV transmission from EVD survivors. It has since been shared with and adapted by other EVD survivor body fluid testing programs and studies in Ebola-affected countries.

Replication-competent infectious hepatitis B virus vectors carrying substantially sized transgenes by redesigned viral polymerase translation.

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Zihua Wang

Full Text Available Viral vectors are engineered virus variants able to deliver nonviral genetic information into cells, usually by the same routes as the parental viruses. For several virus families, replication-competent vectors carrying reporter genes have become invaluable tools for easy and quantitative monitoring of replication and infection, and thus also for identifying antivirals and virus susceptible cells. For hepatitis B virus (HBV, a small enveloped DNA virus causing B-type hepatitis, such vectors are not available because insertions into its tiny 3.2 kb genome almost inevitably affect essential replication elements. HBV replicates by reverse transcription of the pregenomic (pg RNA which is also required as bicistronic mRNA for the capsid (core protein and the reverse transcriptase (Pol; their open reading frames (ORFs overlap by some 150 basepairs. Translation of the downstream Pol ORF does not involve a conventional internal ribosome entry site (IRES. We reasoned that duplicating the overlap region and providing artificial IRES control for translation of both Pol and an in-between inserted transgene might yield a functional tricistronic pgRNA, without interfering with envelope protein expression. As IRESs we used a 22 nucleotide element termed Rbm3 IRES to minimize genome size increase. Model plasmids confirmed its activity even in tricistronic arrangements. Analogous plasmids for complete HBV genomes carrying 399 bp and 720 bp transgenes for blasticidin resistance (BsdR and humanized Renilla green fluorescent protein (hrGFP produced core and envelope proteins like wild-type HBV; while the hrGFP vector replicated poorly, the BsdR vector generated around 40% as much replicative DNA as wild-type HBV. Both vectors, however, formed enveloped virions which were infectious for HBV-susceptible HepaRG cells. Because numerous reporter and effector genes with sizes of around 500 bp or less are available, the new HBV vectors should become highly useful tools to

A heterologous prime-boosting strategy with replicating Vaccinia virus vectors and plant-produced HIV-1 Gag/dgp41 virus-like particles

Energy Technology Data Exchange (ETDEWEB)

Meador, Lydia R. [Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ (United States); Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ (United States); Kessans, Sarah A. [Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ (United States); School of Life Sciences, Arizona State University, Tempe, AZ (United States); Kilbourne, Jacquelyn; Kibler, Karen V. [Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ (United States); Pantaleo, Giuseppe [Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne (Switzerland); Swiss Vaccine Research Institute, Lausanne (Switzerland); Roderiguez, Mariano Esteban [Department of Molecular and Cellular Biology, Centro Nacional de Biotecnologia – CSIC, Madrid (Spain); Blattman, Joseph N. [Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ (United States); School of Life Sciences, Arizona State University, Tempe, AZ (United States); Jacobs, Bertram L., E-mail: bjacobs@asu.edu [Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ (United States); School of Life Sciences, Arizona State University, Tempe, AZ (United States); Mor, Tsafrir S., E-mail: tsafrir.mor@asu.edu [Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ (United States); School of Life Sciences, Arizona State University, Tempe, AZ (United States)

2017-07-15

Showing modest efficacy, the RV144 HIV-1 vaccine clinical trial utilized a non-replicating canarypox viral vector and a soluble gp120 protein boost. Here we built upon the RV144 strategy by developing a novel combination of a replicating, but highly-attenuated Vaccinia virus vector, NYVAC-KC, and plant-produced HIV-1 virus-like particles (VLPs). Both components contained the full-length Gag and a membrane anchored truncated gp41 presenting the membrane proximal external region with its conserved broadly neutralizing epitopes in the pre-fusion conformation. We tested different prime/boost combinations of these components in mice and showed that the group primed with NYVAC-KC and boosted with both the viral vectors and plant-produced VLPs have the most robust Gag-specific CD8 T cell responses, at 12.7% of CD8 T cells expressing IFN-γ in response to stimulation with five Gag epitopes. The same immunization group elicited the best systemic and mucosal antibody responses to Gag and dgp41 with a bias towards IgG1. - Highlights: • We devised a prime/boost anti HIV-1 vaccination strategy modeled after RV144. • We used plant-derived virus-like particles (VLPs) consisting of Gag and dgp41. • We used attenuated, replicating vaccinia virus vectors expressing the same antigens. • The immunogens elicited strong cellular and humoral immune responses.

Recombinant vesicular stomatitis virus vaccine vectors expressing filovirus glycoproteins lack neurovirulence in nonhuman primates.

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Chad E Mire

Full Text Available The filoviruses, Marburg virus and Ebola virus, cause severe hemorrhagic fever with high mortality in humans and nonhuman primates. Among the most promising filovirus vaccines under development is a system based on recombinant vesicular stomatitis virus (rVSV that expresses an individual filovirus glycoprotein (GP in place of the VSV glycoprotein (G. The main concern with all replication-competent vaccines, including the rVSV filovirus GP vectors, is their safety. To address this concern, we performed a neurovirulence study using 21 cynomolgus macaques where the vaccines were administered intrathalamically. Seven animals received a rVSV vector expressing the Zaire ebolavirus (ZEBOV GP; seven animals received a rVSV vector expressing the Lake Victoria marburgvirus (MARV GP; three animals received rVSV-wild type (wt vector, and four animals received vehicle control. Two of three animals given rVSV-wt showed severe neurological symptoms whereas animals receiving vehicle control, rVSV-ZEBOV-GP, or rVSV-MARV-GP did not develop these symptoms. Histological analysis revealed major lesions in neural tissues of all three rVSV-wt animals; however, no significant lesions were observed in any animals from the filovirus vaccine or vehicle control groups. These data strongly suggest that rVSV filovirus GP vaccine vectors lack the neurovirulence properties associated with the rVSV-wt parent vector and support their further development as a vaccine platform for human use.

Expression of Separate Proteins in the Same Plant Leaves and Cells Using Two Independent Virus-Based Gene Vectors

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Maria R. Mendoza

2017-11-01

Full Text Available Plant viral vectors enable the expression of proteins at high levels in a relatively short time. For many purposes (e.g., cell biological interaction studies it may be desirable to express more than one protein in a single cell but that is often not feasible when using a single virus vector. Such a co-expression strategy requires the simultaneous delivery by two compatible and non-competitive viruses that can co-exist to each express a separate protein. Here, we report on the use of two agro-launchable coat-protein gene substitution GFP-expressing virus vector systems based on Tomato bushy stunt virus (TBSV referred to as TG, and Tobacco mosaic virus (TMV annotated as TRBO-G. TG expressed GFP in Nicotiana benthamiana, tomato, lettuce and cowpea, whereas expression from TRBO-G was detected only in the first two species. Upon co-infiltration of the two vectors co-expression was monitored by: molecular detection of the two slightly differently sized GFPs, suppressor-complementation assays, and using TG in combination with TRBO-RFP. All the results revealed that in N. benthamiana and tomato the TBSV and TMV vectors accumulated and expressed proteins in the same plants, the same leaves, and in the same cells. Therefore, co-expression by these two vectors provides a platform for fast and high level expression of proteins to study their cell biology or other properties.

Identification of environmental covariates of West Nile virus vector mosquito population abundance.

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Trawinski, Patricia R; Mackay, D Scott

2010-06-01

The rapid spread of West Nile virus (WNv) in North America is a major public health concern. Culex pipiens-restuans is the principle mosquito vector of WNv in the northeastern United States while Aedes vexans is an important bridge vector of the virus in this region. Vector mosquito abundance is directly dependent on physical environmental factors that provide mosquito habitats. The objective of this research is to determine landscape elements that explain the population abundance and distribution of WNv vector mosquitoes using stepwise linear regression. We developed a novel approach for examining a large set of landscape variables based on a land use and land cover classification by selecting variables in stages to minimize multicollinearity. We also investigated the distance at which landscape elements influence abundance of vector populations using buffer distances of 200, 400, and 1000 m. Results show landscape effects have a significant impact on Cx. pipiens-estuans population distribution while the effects of landscape features are less important for prediction of Ae. vexans population distributions. Cx. pipiens-restuans population abundance is positively correlated with human population density, housing unit density, and urban land use and land cover classes and negatively correlated with age of dwellings and amount of forested land.

Virus infection mediates the effects of elevated CO2 on plants and vectors

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Trębicki, Piotr; Vandegeer, Rebecca K.; Bosque-Pérez, Nilsa A.; Powell, Kevin S.; Dader, Beatriz; Freeman, Angela J.; Yen, Alan L.; Fitzgerald, Glenn J.; Luck, Jo E.

2016-01-01

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production. PMID:26941044

High-titer recombinant adeno-associated virus production utilizing a recombinant herpes simplex virus type I vector expressing AAV-2 Rep and Cap.

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Conway, J E; Rhys, C M; Zolotukhin, I; Zolotukhin, S; Muzyczka, N; Hayward, G S; Byrne, B J

1999-06-01

Recombinant adeno-associated virus type 2 (rAAV) vectors have recently been used to achieve long-term, high level transduction in vivo. Further development of rAAV vectors for clinical use requires significant technological improvements in large-scale vector production. In order to facilitate the production of rAAV vectors, a recombinant herpes simplex virus type I vector (rHSV-1) which does not produce ICP27, has been engineered to express the AAV-2 rep and cap genes. The optimal dose of this vector, d27.1-rc, for AAV production has been determined and results in a yield of 380 expression units (EU) of AAV-GFP produced from 293 cells following transfection with AAV-GFP plasmid DNA. In addition, d27.1-rc was also efficient at producing rAAV from cell lines that have an integrated AAV-GFP provirus. Up to 480 EU/cell of AAV-GFP could be produced from the cell line GFP-92, a proviral, 293 derived cell line. Effective amplification of rAAV vectors introduced into 293 cells by infection was also demonstrated. Passage of rAAV with d27. 1-rc results in up to 200-fold amplification of AAV-GFP with each passage after coinfection of the vectors. Efficient, large-scale production (>109 cells) of AAV-GFP from a proviral cell line was also achieved and these stocks were free of replication-competent AAV. The described rHSV-1 vector provides a novel, simple and flexible way to introduce the AAV-2 rep and cap genes and helper virus functions required to produce high-titer rAAV preparations from any rAAV proviral construct. The efficiency and potential for scalable delivery of d27.1-rc to producer cell cultures should facilitate the production of sufficient quantities of rAAV vectors for clinical application.

The persistence of hepatitis B antigen in the bloodmeal of the ...

African Journals Online (AJOL)

The results are compared with reports on other arthropods which indicate increasing antigen persistence with increasing body size. The findings implicate medicinal leeches as mechanical vectors of HBV and possibly of other medically important viruses, and argue against using leeches of suspect or unknown origin in the ...

Vaccinia virus vectors: new strategies for producing recombinant vaccines.

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Hruby, D E

1990-01-01

The development and continued refinement of techniques for the efficient insertion and expression of heterologous DNA sequences from within the genomic context of infectious vaccinia virus recombinants are among the most promising current approaches towards effective immunoprophylaxis against a variety of protozoan, viral, and bacterial human pathogens. Because of its medical relevance, this area is the subject of intense research interest and has evolved rapidly during the past several years. This review (i) provides an updated overview of the technology that exists for assembling recombinant vaccinia virus strains, (ii) discusses the advantages and disadvantages of these approaches, (iii) outlines the areas of outgoing research directed towards overcoming the limitations of current techniques, and (iv) provides some insight (i.e., speculation) about probable future refinements in the use of vaccinia virus as a vector. PMID:2187593

Low Temperature Storage of Southern Rice Black-Streaked Dwarf Virus-Infected Rice Plants Cannot Sustain Virus Transmission by the Vector.

Science.gov (United States)

Liu, Danfeng; Li, Pei; Han, Yongqiang; Lei, Wenbin; Hou, Maolin

2016-02-01

Southern rice black-streaked dwarf virus (SRBSDV) is a novel virus transmitted by white-backed planthopper Sogatella furcifera (Hováth) (Hemiptera: Delphacidae). Due to low virus transmission efficiency by the planthopper, researchers are frequently confronted with shortage of viruliferous vectors or infected rice plants, especially in winter and the following spring. To find new ways to maintain virus-infected materials, viral rice plants were stored at -80°C for 45 or 140 d and evaluated as virus sources in virus transmission by the vector. SRBSDV virions were not degraded during storage at -80°C as indicated by reverse transcription-polymerase chain reaction and reverse transcription real-time PCR detection. The planthopper nymphs fed on the infected thawed plants for 48 h survived at about 40% and showed positive detection of SRBSDV, but they lost the virus after feeding for another 20 d (the circulative transmission period) on noninfected plants. Transmission electron microscope images indicated broken capsid of virions in infected thawed leaves in contrast to integrity capsid of virions in infected fresh leaves. These results show that low temperature storage of SRBSDV-infected rice plants cannot sustain virus transmission by white-backed planthopper. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Vector competence of Culicoides sonorensis (Diptera: Ceratopogonidae to epizootic hemorrhagic disease virus serotype 7

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Ruder Mark G

2012-10-01

Full Text Available Abstract Background Culicoides sonorensis (Diptera: Ceratopogonidae is a vector of epizootic hemorrhagic disease virus (EHDV serotypes 1 and 2 in North America, where these viruses are well-known pathogens of white-tailed deer (WTD and other wild ruminants. Although historically rare, reports of clinical EHDV infection in cattle have increased in some parts of the world over the past decade. In 2006, an EHDV-7 epizootic in cattle resulted in economic loss for the Israeli dairy industry. White-tailed deer are susceptible to EHDV-7 infection and disease; however, this serotype is exotic to the US and the susceptibility of C. sonorensis to this cattle-virulent EHDV is not known. The objective of the study was to determine if C. sonorensis is susceptible to EHDV-7 infection and is a competent vector. Methods To evaluate the susceptibility of C. sonorensis, midges were fed on EHDV-7 infected WTD, held at 22 ± 1°C, and processed individually for virus isolation and titration on 4–16 days post feeding (dpf. Midges with a virus titer of ≥102.7 median tissue culture infective doses (TCID50/midge were considered potentially competent. To determine if infected C. sonorensis were capable of transmitting EHDV-7 to a host, a susceptible WTD was then fed on by a group of 14–16 dpf midges. Results From 4–16 dpf, 45% (156/350 of midges that fed on WTD with high titer viremia (>107 TCID50/ml were virus isolation-positive, and starting from 10–16 dpf, 32% (35/109 of these virus isolation-positive midges were potentially competent (≥102.7 TCID50/midge. Midges that fed on infected deer transmitted the virus to a susceptible WTD at 14–16 dpf. The WTD developed viremia and severe clinical disease. Conclusion This study demonstrates that C. sonorensis is susceptible to EHDV-7 infection and can transmit the virus to susceptible WTD, thus, C. sonorensis should be considered a potential vector of EHDV-7. Together with previous work, this study demonstrates

Vector competence of Culicoides sonorensis (Diptera: Ceratopogonidae) to epizootic hemorrhagic disease virus serotype 7.

Science.gov (United States)

Ruder, Mark G; Howerth, Elizabeth W; Stallknecht, David E; Allison, Andrew B; Carter, Deborah L; Drolet, Barbara S; Klement, Eyal; Mead, Daniel G

2012-10-17

Culicoides sonorensis (Diptera: Ceratopogonidae) is a vector of epizootic hemorrhagic disease virus (EHDV) serotypes 1 and 2 in North America, where these viruses are well-known pathogens of white-tailed deer (WTD) and other wild ruminants. Although historically rare, reports of clinical EHDV infection in cattle have increased in some parts of the world over the past decade. In 2006, an EHDV-7 epizootic in cattle resulted in economic loss for the Israeli dairy industry. White-tailed deer are susceptible to EHDV-7 infection and disease; however, this serotype is exotic to the US and the susceptibility of C. sonorensis to this cattle-virulent EHDV is not known. The objective of the study was to determine if C. sonorensis is susceptible to EHDV-7 infection and is a competent vector. To evaluate the susceptibility of C. sonorensis, midges were fed on EHDV-7 infected WTD, held at 22 ± 1°C, and processed individually for virus isolation and titration on 4-16 days post feeding (dpf). Midges with a virus titer of ≥ 10(2.7) median tissue culture infective doses (TCID(50))/midge were considered potentially competent. To determine if infected C. sonorensis were capable of transmitting EHDV-7 to a host, a susceptible WTD was then fed on by a group of 14-16 dpf midges. From 4-16 dpf, 45% (156/350) of midges that fed on WTD with high titer viremia (>10(7) TCID(50)/ml) were virus isolation-positive, and starting from 10-16 dpf, 32% (35/109) of these virus isolation-positive midges were potentially competent (≥ 10(2.7) TCID(50)/midge). Midges that fed on infected deer transmitted the virus to a susceptible WTD at 14-16 dpf. The WTD developed viremia and severe clinical disease. This study demonstrates that C. sonorensis is susceptible to EHDV-7 infection and can transmit the virus to susceptible WTD, thus, C. sonorensis should be considered a potential vector of EHDV-7. Together with previous work, this study demonstrates that North America has a susceptible ruminant and

Feeding patterns of potential West Nile virus vectors in south-west Spain.

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Joaquín Muñoz

Full Text Available Mosquito feeding behaviour determines the degree of vector-host contact and may have a serious impact on the risk of West Nile virus (WNV epidemics. Feeding behaviour also interacts with other biotic and abiotic factors that affect virus amplification and transmission.We identified the origin of blood meals in five mosquito species from three different wetlands in SW Spain. All mosquito species analysed fed with different frequencies on birds, mammals and reptiles. Both 'mosquito species' and 'locality' explained a similar amount of variance in the occurrence of avian blood meals. However, 'season of year' was the main factor explaining the presence of human blood meals. The differences in diet resulted in a marked spatial heterogeneity in the estimated WNV transmission risk. Culex perexiguus, Cx. modestus and Cx. pipiens were the main mosquito species involved in WNV enzootic circulation since they feed mainly on birds, were abundant in a number of localities and had high vector competence. Cx. perexiguus may also be important for WNV transmission to horses, as are Cx. pipiens and Cx. theileri in transmission to humans. Estimates of the WNV transmission risk based on mosquito diet, abundance and vector competence matched the results of previous WNV monitoring programs in the area. Our sensitivity analyses suggested that mosquito diet, followed by mosquito abundance and vector competence, are all relevant factors in understanding virus amplification and transmission risk in the studied wild ecosystems. At some of the studied localities, the risk of enzootic circulation of WNV was relatively high, even if the risk of transmission to humans and horses was less.Our results describe for first time the role of five WNV candidate vectors in SW Spain. Interspecific and local differences in mosquito diet composition has an important effect on the potential transmission risk of WNV to birds, horses and humans.

Vector competence of Culicoides sonorensis (Diptera: Ceratopogonidae) to epizootic hemorrhagic disease virus serotype 7

Science.gov (United States)

Background: Culicoides sonorensis (Diptera: Ceratopogonidae) is a vector of epizootic hemorrhagic disease virus (EHDV) serotypes 1 and 2 in North America, where these viruses are well-known pathogens of white-tailed deer (WTD) and other wild ruminants. Although historically rare, reports of clinica...

Immunogenicity of ORFV-based vectors expressing the rabies virus glycoprotein in livestock species.

Science.gov (United States)

Martins, Mathias; Joshi, Lok R; Rodrigues, Fernando S; Anziliero, Deniz; Frandoloso, Rafael; Kutish, Gerald F; Rock, Daniel L; Weiblen, Rudi; Flores, Eduardo F; Diel, Diego G

2017-11-01

The parapoxvirus Orf virus (ORFV) encodes several immunomodulatory proteins (IMPs) that modulate host-innate and pro-inflammatory responses and has been proposed as a vaccine delivery vector for use in animal species. Here we describe the construction and characterization of two recombinant ORFV vectors expressing the rabies virus (RABV) glycoprotein (G). The RABV-G gene was inserted in the ORFV024 or ORFV121 gene loci, which encode for IMPs that are unique to parapoxviruses and inhibit activation of the NF-κB signaling pathway. The immunogenicity of the resultant recombinant viruses (ORFV ∆024 RABV-G or ORFV ∆121 RABV-G, respectively) was evaluated in pigs and cattle. Immunization of the target species with ORFV ∆024 RABV-G and ORFV ∆121 RABV-G elicited robust neutralizing antibody responses against RABV. Notably, neutralizing antibody titers induced in ORFV ∆121 RABV-G-immunized pigs and cattle were significantly higher than those detected in ORFV ∆024 RABV-G-immunized animals, indicating a higher immunogenicity of ORFV Δ121 -based vectors in these animal species. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparing the United States for Zika Virus: Pre-emptive Vector Control and Personal Protection.

Science.gov (United States)

Diaz, James H

2016-12-01

Discovered in 1947 in a monkey in the Zika forest of Uganda, Zika virus was dismissed as a cause of a mild illness that was confined to Africa and Southeast Asia and transmitted by Aedes mosquitoes. In 2007, Zika virus appeared outside of its endemic borders in an outbreak on the South Pacific Island of Yap. In 2013, Zika virus was associated with a major neurological complication, Guillain-Barré syndrome, in a larger outbreak in the French Polynesian Islands. From the South Pacific, Zika invaded Brazil in 2015 and caused another severe neurological complication, fetal microcephaly. The mosquito-borne transmission of Zika virus can be propagated by sexual transmission and, possibly, by blood transfusions, close personal contacts, and organ transplants, like other flaviviruses. Since these combined mechanisms of infectious disease transmission could result in catastrophic incidences of severe neurological diseases in adults and children, the public should know what to expect from Zika virus, how to prevent infection, and what the most likely failures in preventive measures will be. With federal research funding stalled, a Zika vaccine is far away. The only national strategies to prepare the United States for Zika virus invasion now are effective vector control measures and personal protection from mosquito bites. In addition to a basic knowledge of Aedes mosquito vectors and their biting behaviors, an understanding of simple household vector control measures, and the selection of the best chemical and physical mosquito repellents will be required to repel the Zika threat. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Simian virus 40 vectors for pulmonary gene therapy

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Oppenheim Ariella

2007-10-01

Full Text Available Abstract Background Sepsis remains the leading cause of death in critically ill patients. One of the primary organs affected by sepsis is the lung, presenting as the Acute Respiratory Distress Syndrome (ARDS. Organ damage in sepsis involves an alteration in gene expression, making gene transfer a potential therapeutic modality. This work examines the feasibility of applying simian virus 40 (SV40 vectors for pulmonary gene therapy. Methods Sepsis-induced ARDS was established by cecal ligation double puncture (2CLP. SV40 vectors carrying the luciferase reporter gene (SV/luc were administered intratracheally immediately after sepsis induction. Sham operated (SO as well as 2CLP rats given intratracheal PBS or adenovirus expressing luciferase served as controls. Luc transduction was evaluated by in vivo light detection, immunoassay and luciferase mRNA detection by RT-PCR in tissue harvested from septic rats. Vector abundance and distribution into alveolar cells was evaluated using immunostaining for the SV40 VP1 capsid protein as well as by double staining for VP1 and for the surfactant protein C (proSP-C. Immunostaining for T-lymphocytes was used to evaluate the cellular immune response induced by the vector. Results Luc expression measured by in vivo light detection correlated with immunoassay from lung tissue harvested from the same rats. Moreover, our results showed vector presence in type II alveolar cells. The vector did not induce significant cellular immune response. Conclusion In the present study we have demonstrated efficient uptake and expression of an SV40 vector in the lungs of animals with sepsis-induced ARDS. These vectors appear to be capable of in vivo transduction of alveolar type II cells and may thus become a future therapeutic tool.

HoBi-like virus challenge of pregnant cows that had previously given birth to calves persistently infected with bovine viral diarrhea virus

Science.gov (United States)

The ability of bovine viral diarrhea viruses (BVDV) to establish persistent infection (PI) following fetal infection is central to keeping these viruses circulating. Similarly, an emerging species of pestivirus, HoBi-like viruses, is also able to establish PIs. Dams that are not PI, but carrying PI ...

THE MOLECULAR MECHANISMS OF EPSTEINBARR VIRUS PERSISTENCE IN THE HUMAN ORGANISM

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Volyanskiy A.Yu.

2014-12-01

Full Text Available This review describes advances in molecular aspects of EBV infection and disease. We discuss the spectrum of clinical illness due to EBV persistent infection. The main characteristic of Epstein-Barr virus (EBV is that initial infection results in lifelong persistence. EBV infects nearly all humans by the time they reach adulthood. Healthy humans have approximately 1 to 50 infected cells per million leukocytes. EBV is one of the eight known human herpesviruses. EBV virions have a doublestranded linear DNA and 100 genes had been described in virus genome. Initial infection is thought to occur in the oral compartment. The host cells of EBV are mainly lymphocytes and epithelial cells. EBV attaches to B cells via binding of the viral gp350 protein to CD21 receptor. The consequence of EBV infection is cells proliferation and differentiation into memory B lymphocyte in the germinal center. Infected memory B cells are released into the peripheral circulation. EBV persists mostly in the memory B cell. Latency is the state of persistent viral infection without active viral production. In latently infected B cells EBV virus exist as episomes. During the latent phase episomal replication occurs via host DNA polymerase. Genes of the nuclear antigens (EBNA and latent membrane proteins (LMP are transcribed during latency. These include EBNA1, EBNA2, EBNA3A, EBNA3B, EBNA3C, EBNA leader protein (EBNALP, LMP1 and LMP2 genes. All nuclear antigens are transcription transactivators which bind to cis-regulatory DNA elements of cell or virus genomes directly or in complex with other proteins. LMP2A and LMP1 can function to coordinately mimic B-cell receptor and CD40 coreceptor signaling in latently infected B cells. LMP proteins activate cell signaling systems and as the consequence different gene expression programs. Characterization of gene expression patterns in different cell lines and pathologic conditions has revealed that there are at least three different

Effects of virus dose and extrinsic incubation temperature on vector competence of Culex nigripalpus (Diptera: Culicidae) for St. Louis encephalitis virus.

Science.gov (United States)

Richards, Stephanie L; Anderson, Sheri L; Lord, Cynthia C; Tabachnick, Walter J

2012-11-01

Culex nigripalpus Theobald is a primary vector of St. Louis encephalitis virus in the southeastern United States. Cx. nigripalpus females were fed blood containing a low (4.0 +/- 0.01 log10 plaque-forming unit equivalents (PFUeq) /ml) or high (4.7 +/- 0.1 log10 PFUeq/ml) St. Louis encephalitis virus dose and maintained at extrinsic incubation temperatures (EIT) of 25 or 28 degrees C for 12 d. Vector competence was measured via quantitative real-time reverse transcriptase polymerase chain reaction to estimate PFUeq using rates of infection, dissemination, and transmission. There were no differences in infection rates between the two EITs at either dose. The low dose had higher infection rates at both EITs. Dissemination rates were significantly higher at 28 degrees C compared with 25 degrees C at both doses. Virus transmission was observed (<7%) only at 28 degrees C for both doses. The virus titer in body tissues was greater at 28 degrees C compared with 25 degrees C at both doses. The difference between the EITs was greater at the low dose, resulting in a higher titer for the low dose than the high dose at 28 degrees C. Virus titers in leg tissues were greater in mosquitoes fed the high versus low dose, but were not influenced by EIT. Further investigations using a variety of environmental and biological factors would be useful in exploring the complexity of vector competence.

Efficient Strategy to Generate a Vectored Duck Enteritis Virus Delivering Envelope of Duck Tembusu Virus

Directory of Open Access Journals (Sweden)

Zhong Zou

2014-06-01

Full Text Available Duck Tembusu virus (DTMUV is a recently emerging pathogenic flavivirus that has resulted in a huge economic loss in the duck industry. However, no vaccine is currently available to control this pathogen. Consequently, a practical strategy to construct a vaccine against this pathogen should be determined. In this study, duck enteritis virus (DEV was examined as a candidate vaccine vector to deliver the envelope (E of DTMUV. A modified mini-F vector was inserted into the SORF3 and US2 gene junctions of the attenuated DEV vaccine strain C-KCE genome to generate an infectious bacterial artificial chromosome (BAC of C-KCE (vBAC-C-KCE. The envelope (E gene of DTMUV was inserted into the C-KCE genome through the mating-assisted genetically integrated cloning (MAGIC strategy, resulting in the recombinant vector, pBAC-C-KCE-E. A bivalent vaccine C-KCE-E was generated by eliminating the BAC backbone. Immunofluorescence and western blot analysis results indicated that the E proteins were vigorously expressed in C-KCE-E-infected chicken embryo fibroblasts (CEFs. Duck experiments demonstrated that the insertion of the E gene did not alter the protective efficacy of C-KCE. Moreover, C-KCE-E-immunized ducks induced neutralization antibodies against DTMUV. These results demonstrated, for the first time, that recombinant C-KCE-E can serve as a potential bivalent vaccine against DEV and DTMUV.

Spread of Zika virus:The key role of mosquito vector control

Institute of Scientific and Technical Information of China (English)

Giovanni Benelli

2016-01-01

Mosquitoes (Diptera: Culicidae) represent a key threat for millions of humans and ani-mals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean, represent the most recent four arrivals of important arboviruses in the western hemi-sphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above, it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nano-particles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation (i.e. the“lure and kill”approach), pheromone traps, sound traps need further research attention. In particular, detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required.

Spread of Zika virus:The key role of mosquito vector control

Institute of Scientific and Technical Information of China (English)

Giovanni Benelli

2016-01-01

Mosquitoes(Diptera: Culicidae) represent a key threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens,including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean,represent the most recent four arrivals of important arboviruses in the western hemisphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above,it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nanoparticles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation(i.e. the "lure and kill"approach), pheromone traps, sound traps need further research attention. In particular,detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required.

Spread of Zika virus: The key role of mosquito vector control

Directory of Open Access Journals (Sweden)

Giovanni Benelli

2016-06-01

Full Text Available Mosquitoes (Diptera: Culicidae represent a key threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean, represent the most recent four arrivals of important arboviruses in the western hemisphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above, it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nanoparticles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation (i.e. the “lure and kill” approach, pheromone traps, sound traps need further research attention. In particular, detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required.

Transcriptome of the Plant Virus Vector Graminella nigrifrons, and the Molecular Interactions of Maize fine streak rhabdovirus Transmission

Science.gov (United States)

Chen, Yuting; Cassone, Bryan J.; Bai, Xiaodong; Redinbaugh, Margaret G.; Michel, Andrew P.

2012-01-01

Background Leafhoppers (Hemiptera: Cicadellidae) are plant-phloem feeders that are known for their ability to vector plant pathogens. The black-faced leafhopper (Graminella nigrifrons) has been identified as the only known vector for the Maize fine streak virus (MFSV), an emerging plant pathogen in the Rhabdoviridae. Within G. nigrifrons populations, individuals can be experimentally separated into three classes based on their capacity for viral transmission: transmitters, acquirers and non-acquirers. Understanding the molecular interactions between vector and virus can reveal important insights in virus immune defense and vector transmission. Results RNA sequencing (RNA-Seq) was performed to characterize the transcriptome of G. nigrifrons. A total of 38,240 ESTs of a minimum 100 bp were generated from two separate cDNA libraries consisting of virus transmitters and acquirers. More than 60% of known D. melanogaster, A. gambiae, T. castaneum immune response genes mapped to our G. nigrifrons EST database. Real time quantitative PCR (RT-qPCR) showed significant down-regulation of three genes for peptidoglycan recognition proteins (PGRP – SB1, SD, and LC) in G. nigrifrons transmitters versus control leafhoppers. Conclusions Our study is the first to characterize the transcriptome of a leafhopper vector species. Significant sequence similarity in immune defense genes existed between G. nigrifrons and other well characterized insects. The down-regulation of PGRPs in MFSV transmitters suggested a possible role in rhabdovirus transmission. The results provide a framework for future studies aimed at elucidating the molecular mechanisms of plant virus vector competence. PMID:22808205

Transcriptome of the plant virus vector Graminella nigrifrons, and the molecular interactions of maize fine streak rhabdovirus transmission.

Directory of Open Access Journals (Sweden)

Yuting Chen

Full Text Available BACKGROUND: Leafhoppers (HEmiptera: Cicadellidae are plant-phloem feeders that are known for their ability to vector plant pathogens. The black-faced leafhopper (Graminella nigrifrons has been identified as the only known vector for the Maize fine streak virus (MFSV, an emerging plant pathogen in the Rhabdoviridae. Within G. nigrifrons populations, individuals can be experimentally separated into three classes based on their capacity for viral transmission: transmitters, acquirers and non-acquirers. Understanding the molecular interactions between vector and virus can reveal important insights in virus immune defense and vector transmission. RESULTS: RNA sequencing (RNA-Seq was performed to characterize the transcriptome of G. nigrifrons. A total of 38,240 ESTs of a minimum 100 bp were generated from two separate cDNA libraries consisting of virus transmitters and acquirers. More than 60% of known D. melanogaster, A. gambiae, T. castaneum immune response genes mapped to our G. nigrifrons EST database. Real time quantitative PCR (RT-qPCR showed significant down-regulation of three genes for peptidoglycan recognition proteins (PGRP - SB1, SD, and LC in G. nigrifrons transmitters versus control leafhoppers. CONCLUSIONS: Our study is the first to characterize the transcriptome of a leafhopper vector species. Significant sequence similarity in immune defense genes existed between G. nigrifrons and other well characterized insects. The down-regulation of PGRPs in MFSV transmitters suggested a possible role in rhabdovirus transmission. The results provide a framework for future studies aimed at elucidating the molecular mechanisms of plant virus vector competence.

A novel and highly efficient production system for recombinant adeno-associated virus vector.

Science.gov (United States)

Wu, Zhijian; Wu, Xiaobing; Cao, Hui; Dong, Xiaoyan; Wang, Hong; Hou, Yunde

2002-02-01

Recombinant adeno-associated virus (rAAV) has proven to be a promising gene delivery vector for human gene therapy. However, its application has been limited by difficulty in obtaining enough quantities of high-titer vector stocks. In this paper, a novel and highly efficient production system for rAAV is described. A recombinant herpes simplex virus type 1 (rHSV-1) designated HSV1-rc/DeltaUL2, which expressed adeno-associated virus type2 (AAV-2) Rep and Cap proteins, was constructed previously. The data confirmed that its functions were to support rAAV replication and packaging, and the generated rAAV was infectious. Meanwhile, an rAAV proviral cell line designated BHK/SG2, which carried the green fluorescent protein (GFP) gene expression cassette, was established by transfecting BHK-21 cells with rAAV vector plasmid pSNAV-2-GFP. Infecting BHK/SG2 with HSV1-rc/DeltaUL2 at an MOI of 0.1 resulted in the optimal yields of rAAV, reaching 250 transducing unit (TU) or 4.28x10(4) particles per cell. Therefore, compared with the conventional transfection method, the yield of rAAV using this "one proviral cell line, one helper virus" strategy was increased by two orders of magnitude. Large-scale production of rAAV can be easily achieved using this strategy and might meet the demands for clinical trials of rAAV-mediated gene therapy.

Characterization of Sendai virus persistently infected L929 cells and Sendai virus pi strain: recombinant Sendai viruses having Mpi protein shows lower cytotoxicity and are incapable of establishing persistent infection

International Nuclear Information System (INIS)

Nishio, Machiko; Tsurudome, Masato; Ito, Morihiro; Kawano, Mitsuo; Komada, Hiroshi; Ito, Yasuhiko

2003-01-01

It is commonly accepted that the temperature-sensitive phenotype of Sendai virus (SeV) persistently infected cells is caused by the M and/or HN proteins. Expression level of the L, M, HN, and V proteins is extremely low in L929 cells persistently infected with SeVpi (L929/SeVpi cells) incubated at 38 deg. C. The HN protein quickly disappears in L929/SeVpi cells following a temperature shift up to 38 deg. C, and pulse-chase experiments show that the Lpi, HNpi, and Mpi proteins are unstable at 38 deg. C. Following a temperature shift either upward or downward, M protein is translocated into the nucleus and then localizes to the perinuclear region. None of virus-specific polypeptides are detected in the cells primarily infected with SeVpi and incubated at 38 deg. C and virus proteins are not pulse-labeled at 38 deg. C, indicating that temperature-sensitive step is at an early stage of infection. The Mpi protein is transiently located in the nucleus of the SeVpi primarily infected cells. Recombinant SeVs possessing the HNpi or/and Mpi proteins are not temperature-sensitive. The HN protein is expressed at very low levels and the F protein localizes to the perinuclear region in rSeV(Mpi)-infected cells incubated at 38 deg. C for 18 h. rSeVs having the Mpi protein exhibit lower cytotoxicity and are incapable of establishing persistent infection. Amino acid 116 of the Mpi protein is related to the nuclear translocation and lower cytopathogenesis, whereas aa183 is involved in the interaction between M protein and viral glycoproteins

Role of Pea Enation Mosaic Virus Coat Protein in the Host Plant and Aphid Vector.

Science.gov (United States)

Doumayrou, Juliette; Sheber, Melissa; Bonning, Bryony C; Miller, W Allen

2016-11-18

Understanding the molecular mechanisms involved in plant virus-vector interactions is essential for the development of effective control measures for aphid-vectored epidemic plant diseases. The coat proteins (CP) are the main component of the viral capsids, and they are implicated in practically every stage of the viral infection cycle. Pea enation mosaic virus 1 (PEMV1, Enamovirus , Luteoviridae ) and Pea enation mosaic virus 2 (PEMV2, Umbravirus , Tombusviridae ) are two RNA viruses in an obligate symbiosis causing the pea enation mosaic disease. Sixteen mutant viruses were generated with mutations in different domains of the CP to evaluate the role of specific amino acids in viral replication, virion assembly, long-distance movement in Pisum sativum , and aphid transmission. Twelve mutant viruses were unable to assemble but were able to replicate in inoculated leaves, move long-distance, and express the CP in newly infected leaves. Four mutant viruses produced virions, but three were not transmissible by the pea aphid, Acyrthosiphon pisum . Three-dimensional modeling of the PEMV CP, combined with biological assays for virion assembly and aphid transmission, allowed for a model of the assembly of PEMV coat protein subunits.

An efficient deletion mutant packaging system for defective herpes simplex virus vectors: Potential applications to human gene therapy and neuronal physiology

International Nuclear Information System (INIS)

Geller, A.I.; Keyomarsi, K.; Bryan, J.; Pardee, A.B.

1990-01-01

The authors have previously described a defective herpes simplex virus (HSV-1) vector system that permits that introduction of virtually any gene into nonmitotic cells. pHSVlac, the prototype vector, stably expresses Escherichia coli β-galactosidase from a constitutive promoter in many human cell lines, in cultured rat neurons from throughout the nervous system, and in cells in the adult rat brain. HSV-1 vectors expressing other genes may prove useful for studying neuronal physiology or performing human gene therapy for neurological diseases, such as Parkinson disease or brain tumors. A HSV-1 temperature-sensitive (ts) mutant, ts K, has been used as helper virus; ts mutants revert to wild type. In contrast, HSV-1 deletion mutants essentially cannot revert to wild type; therefore, use of a deletion mutant as helper virus might permit human gene therapy with HSV-1 vectors. They now report an efficient packaging system for HSV-1 VECTORS USING A DELETION MUTANT, d30EBA, as helper virus; virus is grown on the complementing cell line M64A. pHSVlac virus prepared using the deletion mutant packaging system stably expresses β-galactosidase in cultured rat sympathetic neurons and glia. Both D30EBA and ts K contain a mutation in the IE3 gene of HSV-1 strain 17 and have the same phenotype; therefore, changing the helper virus from ts K to D30EBA does not alter the host range or other properties of the HSV-1 vector system

Assessing the impact of climate change on vector-borne viruses in the EU through the elicitation of expert opinion.

Science.gov (United States)

Gale, P; Brouwer, A; Ramnial, V; Kelly, L; Kosmider, R; Fooks, A R; Snary, E L

2010-02-01

Expert opinion was elicited to undertake a qualitative risk assessment to estimate the current and future risks to the European Union (EU) from five vector-borne viruses listed by the World Organization for Animal Health. It was predicted that climate change will increase the risk of incursions of African horse sickness virus (AHSV), Crimean-Congo haemorrhagic fever virus (CCHFV) and Rift Valley fever virus (RVFV) into the EU from other parts of the world, with African swine fever virus (ASFV) and West Nile virus (WNV) being less affected. Currently the predicted risks of incursion were lowest for RVFV and highest for ASFV. Risks of incursion were considered for six routes of entry (namely vectors, livestock, meat products, wildlife, pets and people). Climate change was predicted to increase the risk of incursion from entry of vectors for all five viruses to some degree, the strongest effects being predicted for AHSV, CCHFV and WNV. This work will facilitate identification of appropriate risk management options in relation to adaptations to climate change.

Efficient gene transfer into nondividing cells by adeno-associated virus-based vectors.

OpenAIRE

Podsakoff, G; Wong, K K; Chatterjee, S

1994-01-01

Gene transfer vectors based on adeno-associated virus (AAV) are emerging as highly promising for use in human gene therapy by virtue of their characteristics of wide host range, high transduction efficiencies, and lack of cytopathogenicity. To better define the biology of AAV-mediated gene transfer, we tested the ability of an AAV vector to efficiently introduce transgenes into nonproliferating cell populations. Cells were induced into a nonproliferative state by treatment with the DNA synthe...

Parainfluenza Virus Infection Sensitizes Cancer Cells to DNA-Damaging Agents: Implications for Oncolytic Virus Therapy.

Science.gov (United States)

Fox, Candace R; Parks, Griffith D

2018-04-01

A parainfluenza virus 5 (PIV5) with mutations in the P/V gene (P/V-CPI - ) is restricted for spread in normal cells but not in cancer cells in vitro and is effective at reducing tumor burdens in mouse model systems. Here we show that P/V-CPI - infection of HEp-2 human laryngeal cancer cells results in the majority of the cells dying, but unexpectedly, over time, there is an emergence of a population of cells that survive as P/V-CPI - persistently infected (PI) cells. P/V-CPI - PI cells had elevated levels of basal caspase activation, and viability was highly dependent on the activity of cellular inhibitor-of-apoptosis proteins (IAPs) such as Survivin and XIAP. In challenge experiments with external inducers of apoptosis, PI cells were more sensitive to cisplatin-induced DNA damage and cell death. This increased cisplatin sensitivity correlated with defects in DNA damage signaling pathways such as phosphorylation of Chk1 and translocation of damage-specific DNA binding protein 1 (DDB1) to the nucleus. Cisplatin-induced killing of PI cells was sensitive to the inhibition of wild-type (WT) p53-inducible protein 1 (WIP1), a phosphatase which acts to terminate DNA damage signaling pathways. A similar sensitivity to cisplatin was seen with cells during acute infection with P/V-CPI - as well as during acute infections with WT PIV5 and the related virus human parainfluenza virus type 2 (hPIV2). Our results have general implications for the design of safer paramyxovirus-based vectors that cannot establish PI as well as the potential for combining chemotherapy with oncolytic RNA virus vectors. IMPORTANCE There is intense interest in developing oncolytic viral vectors with increased potency against cancer cells, particularly those cancer cells that have gained resistance to chemotherapies. We have found that infection with cytoplasmically replicating parainfluenza virus can result in increases in the killing of cancer cells by agents that induce DNA damage, and this is linked

Infection of potato plants with potato leafroll virus changes attraction and feeding behaviour of Myzus persicae

NARCIS (Netherlands)

Alvarez, A.E.; Garzo, E.; Verbeek, M.; Vosman, B.; Dicke, M.; Tjallingii, W.F.

2007-01-01

Potato leafroll virus (PLRV; genus Polerovirus, family Luteoviridae) is a persistently transmitted circulative virus that depends on aphids for spreading. The primary vector of PLRV is the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae). Solanum tuberosum L. potato cv. Kardal (Solanaceae) has a

Coat protein sequence shows that Cucumber mosaic virus isolate ...

Indian Academy of Sciences (India)

Madhu

A viral disease was identified on geraniums (Pelargonium spp.) grown in a greenhouse at the .... DNA was cloned in p-GEM Teasy vector (Promega, USA) as per the ... M. persicae and A. gossypii transmitted the virus in non persistent manner ...

Persistence of Antibodies to West Nile Virus in Naturally Infected Rock Pigeons (Columba livia)

Science.gov (United States)

Gibbs, Samantha E. J.; Hoffman, Douglas M.; Stark, Lillian M.; Marlenee, Nicole L.; Blitvich, Bradley J.; Beaty, Barry J.; Stallknecht, David E.

2005-01-01

Wild caught rock pigeons (Columba livia) with antibodies to West Nile virus were monitored for 15 months to determine antibody persistence and compare results of three serologic techniques. Antibodies persisted for the entire study as detected by epitope-blocking enzyme-linked immunosorbent assay and plaque reduction neutralization test. Maternal antibodies in squabs derived from seropositive birds persisted for an average of 27 days. PMID:15879030

A virus vector based on Canine Herpesvirus for vaccine applications in canids.

Science.gov (United States)

Strive, T; Hardy, C M; Wright, J; Reubel, G H

2007-01-31

Canine Herpesvirus (CHV) is being developed as a virus vector for the vaccination of European red foxes. However, initial studies using recombinant CHV vaccines in foxes revealed viral attenuation and lack of antibody response to inserted foreign antigens. These findings were attributed both to inactivation of the thymidine kinase (TK) gene and excess foreign genetic material in the recombinant viral genome. In this study, we report an improved CHV-bacterial artificial chromosome (BAC) vector system designed to overcome attenuation in foxes. A non-essential region was identified in the CHV genome as an alternative insertion site for foreign genes. Replacement of a guanine/cytosine (GC)-rich intergenic region between UL21 and UL22 of CHV with a marker gene did not change growth behaviour in vitro, showing that this region is not essential for virus growth in cell culture. We subsequently produced a CHV-BAC vector with an intact TK gene in which the bacterial genes and the antigen expression cassette were inserted into this GC-rich locus. Unlike earlier constructs, the new CHV-BAC allowed self-excision of the bacterial genes via homologous recombination after transfection of BACs into cell culture. The BAC-CHV system was used to produce a recombinant virus that constitutively expressed porcine zona pellucida subunit C protein between the UL21 and UL22 genes of CHV. Complete self-excision of the bacterial genes from CHV was achieved within one round of replication whilst retaining antigen gene expression.

Role of Pea Enation Mosaic Virus Coat Protein in the Host Plant and Aphid Vector

Directory of Open Access Journals (Sweden)

Juliette Doumayrou

2016-11-01

Full Text Available Understanding the molecular mechanisms involved in plant virus–vector interactions is essential for the development of effective control measures for aphid-vectored epidemic plant diseases. The coat proteins (CP are the main component of the viral capsids, and they are implicated in practically every stage of the viral infection cycle. Pea enation mosaic virus 1 (PEMV1, Enamovirus, Luteoviridae and Pea enation mosaic virus 2 (PEMV2, Umbravirus, Tombusviridae are two RNA viruses in an obligate symbiosis causing the pea enation mosaic disease. Sixteen mutant viruses were generated with mutations in different domains of the CP to evaluate the role of specific amino acids in viral replication, virion assembly, long-distance movement in Pisum sativum, and aphid transmission. Twelve mutant viruses were unable to assemble but were able to replicate in inoculated leaves, move long-distance, and express the CP in newly infected leaves. Four mutant viruses produced virions, but three were not transmissible by the pea aphid, Acyrthosiphon pisum. Three-dimensional modeling of the PEMV CP, combined with biological assays for virion assembly and aphid transmission, allowed for a model of the assembly of PEMV coat protein subunits.

Ebola virus and arthropods: a literature review and entomological consideration on the vector role.

Science.gov (United States)

Dutto, M; Bertero, M; Petrosillo, N; Pombi, M; Otranto, D

2016-10-01

Ebola virus is a pathogen responsible for a severe disease that affects humans and several animal species. To date, the natural reservoir of this virus is not known with certainty, although it is believed that fruit bats (Chiroptera: Pteropodidae) play an important role in maintaining the virus in nature. Although information on viral transmission from animals to humans is not clear, the role of arthropods has come under suspicion. In this article, we review the potential role of arthropods in spreading Ebola virus, acting as mechanical or biological vectors.

Multiplication of maize rayado fino virus in the leafhopper vector Dalbulus maidis.

Science.gov (United States)

Rivera, C; Gámez, R

1986-01-01

The enzyme-linked immunosorbent assay (ELISA) was used to demonstrate the increase in titer of maize rayado fino virus (MRFV) in its leafhopper vector, Dalbulus maidis. Viral antigen concentration attained a maximum in the body of the insect 25 days after virus acquisition and decreased thereafter. Substantial differences in concentration were observed among viruliferous leafhoppers. MRFV was serially passed through 5 successive leafhopper populations. The results provide further evidence of multiplication of MRFV in D. maidis.

Implementation of a study to examine the persistence of Ebola virus in the body fluids of Ebola virus disease survivors in Sierra Leone: Methodology and lessons learned.

Science.gov (United States)

Deen, Gibrilla Fadlu; McDonald, Suzanna L R; Marrinan, Jaclyn E; Sesay, Foday R; Ervin, Elizabeth; Thorson, Anna E; Xu, Wenbo; Ströher, Ute; Ongpin, Patricia; Abad, Neetu; Ariyarajah, Archchun; Malik, Tasneem; Liu, Hongtu; Ross, Christine; Durski, Kara N; Gaillard, Philippe; Morgan, Oliver; Formenty, Pierre; Knust, Barbara; Broutet, Nathalie; Sahr, Foday

2017-09-01

The 2013-2016 West African Ebola virus disease epidemic was unprecedented in terms of the number of cases and survivors. Prior to this epidemic there was limited data available on the persistence of Ebola virus in survivors' body fluids and the potential risk of transmission, including sexual transmission. Given the urgent need to determine the persistence of Ebola virus in survivors' body fluids, an observational cohort study was designed and implemented during the epidemic response operation in Sierra Leone. This publication describes study implementation methodology and the key lessons learned. Challenges encountered during implementation included unforeseen duration of follow-up, complexity of interpreting and communicating laboratory results to survivors, and the urgency of translating research findings into public health practice. Strong community engagement helped rapidly implement the study during the epidemic. The study was conducted in two phases. The first phase was initiated within five months of initial protocol discussions and assessed persistence of Ebola virus in semen of 100 adult men. The second phase assessed the persistence of virus in multiple body fluids (semen or vaginal fluid, menstrual blood, breast milk, and urine, rectal fluid, sweat, saliva, tears), of 120 men and 120 women. Data from this study informed national and global guidelines in real time and demonstrated the need to implement semen testing programs among Ebola virus disease survivors. The lessons learned and study tools developed accelerated the implementation of such programs in Ebola virus disease affected countries, and also informed studies examining persistence of Zika virus. Research is a vital component of the public health response to an epidemic of a poorly characterized disease. Adequate resources should be rapidly made available to answer critical research questions, in order to better inform response efforts.

Zika Virus Persistently and Productively Infects Primary Adult Sensory Neurons In Vitro

Directory of Open Access Journals (Sweden)

Brianna K. Swartwout

2017-10-01

Full Text Available Zika virus (ZIKV has recently surged in human populations, causing an increase in congenital and Guillain-Barré syndromes. While sexual transmission and presence of ZIKV in urine, semen, vaginal secretions, and saliva have been established, the origin of persistent virus shedding into biological secretions is not clear. Using a primary adult murine neuronal culture model, we have determined that ZIKV persistently and productively infects sensory neurons of the trigeminal and dorsal root ganglia, which innervate glands and mucosa of the face and the genitourinary tract, respectively, without apparent injury. Autonomic neurons that innervate these regions are not permissive for infection. However, productive ZIKV infection of satellite glial cells that surround and support sensory and autonomic neurons in peripheral ganglia results in their destruction. Persistent infection of sensory neurons, without affecting their viability, provides a potential reservoir for viral shedding in biological secretions for extended periods of time after infection. Furthermore, viral destruction of satellite glial cells may contribute to the development of Guillain-Barré Syndrome via an alternative mechanism to the established autoimmune response.

Zika Virus Persistently and Productively Infects Primary Adult Sensory Neurons In Vitro.

Science.gov (United States)

Swartwout, Brianna K; Zlotnick, Marta G; Saver, Ashley E; McKenna, Caroline M; Bertke, Andrea S

2017-10-13

Zika virus (ZIKV) has recently surged in human populations, causing an increase in congenital and Guillain-Barré syndromes. While sexual transmission and presence of ZIKV in urine, semen, vaginal secretions, and saliva have been established, the origin of persistent virus shedding into biological secretions is not clear. Using a primary adult murine neuronal culture model, we have determined that ZIKV persistently and productively infects sensory neurons of the trigeminal and dorsal root ganglia, which innervate glands and mucosa of the face and the genitourinary tract, respectively, without apparent injury. Autonomic neurons that innervate these regions are not permissive for infection. However, productive ZIKV infection of satellite glial cells that surround and support sensory and autonomic neurons in peripheral ganglia results in their destruction. Persistent infection of sensory neurons, without affecting their viability, provides a potential reservoir for viral shedding in biological secretions for extended periods of time after infection. Furthermore, viral destruction of satellite glial cells may contribute to the development of Guillain-Barré Syndrome via an alternative mechanism to the established autoimmune response.

Case Report: Emergence of bovine viral diarrhea virus persistently infected calves in a closed herd

Science.gov (United States)

Bovine viral diarrhea virus (BVDV) continues to have significant economic impact on the cattle industry worldwide. The virus is primarily maintained in the cattle population due to persistently infected animals. Herd surveillance along with good vaccination programs and biosecurity practices are the...

Infection of the whitefly Bemisia tabaci with Rickettsia spp. alters its interactions with Tomato yellow leaf curl virus

Science.gov (United States)

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...

Thymidine Kinase-Negative Herpes Simplex Virus 1 Can Efficiently Establish Persistent Infection in Neural Tissues of Nude Mice.

Science.gov (United States)

Huang, Chih-Yu; Yao, Hui-Wen; Wang, Li-Chiu; Shen, Fang-Hsiu; Hsu, Sheng-Min; Chen, Shun-Hua

2017-02-15

Herpes simplex virus 1 (HSV-1) establishes latency in neural tissues of immunocompetent mice but persists in both peripheral and neural tissues of lymphocyte-deficient mice. Thymidine kinase (TK) is believed to be essential for HSV-1 to persist in neural tissues of immunocompromised mice, because infectious virus of a mutant with defects in both TK and UL24 is detected only in peripheral tissues, but not in neural tissues, of severe combined immunodeficiency mice (T. Valyi-Nagy, R. M. Gesser, B. Raengsakulrach, S. L. Deshmane, B. P. Randazzo, A. J. Dillner, and N. W. Fraser, Virology 199:484-490, 1994, https://doi.org/10.1006/viro.1994.1150). Here we find infiltration of CD4 and CD8 T cells in peripheral and neural tissues of mice infected with a TK-negative mutant. We therefore investigated the significance of viral TK and host T cells for HSV-1 to persist in neural tissues using three genetically engineered mutants with defects in only TK or in both TK and UL24 and two strains of nude mice. Surprisingly, all three mutants establish persistent infection in up to 100% of brain stems and 93% of trigeminal ganglia of adult nude mice at 28 days postinfection, as measured by the recovery of infectious virus. Thus, in mouse neural tissues, host T cells block persistent HSV-1 infection, and viral TK is dispensable for the virus to establish persistent infection. Furthermore, we found 30- to 200-fold more virus in neural tissues than in the eye and detected glycoprotein C, a true late viral antigen, in brainstem neurons of nude mice persistently infected with the TK-negative mutant, suggesting that adult mouse neurons can support the replication of TK-negative HSV-1. Acyclovir is used to treat herpes simplex virus 1 (HSV-1)-infected immunocompromised patients, but treatment is hindered by the emergence of drug-resistant viruses, mostly those with mutations in viral thymidine kinase (TK), which activates acyclovir. TK mutants are detected in brains of immunocompromised

Viral vector-based influenza vaccines

Science.gov (United States)

de Vries, Rory D.; Rimmelzwaan, Guus F.

2016-01-01

ABSTRACT Antigenic drift of seasonal influenza viruses and the occasional introduction of influenza viruses of novel subtypes into the human population complicate the timely production of effective vaccines that antigenically match the virus strains that cause epidemic or pandemic outbreaks. The development of game-changing vaccines that induce broadly protective immunity against a wide variety of influenza viruses is an unmet need, in which recombinant viral vectors may provide. Use of viral vectors allows the delivery of any influenza virus antigen, or derivative thereof, to the immune system, resulting in the optimal induction of virus-specific B- and T-cell responses against this antigen of choice. This systematic review discusses results obtained with vectored influenza virus vaccines and advantages and disadvantages of the currently available viral vectors. PMID:27455345

Persistence of subclinical deformed wing virus infections in honeybees following Varroa mite removal and a bee population turnover.

Directory of Open Access Journals (Sweden)

Barbara Locke

Full Text Available Deformed wing virus (DWV is a lethal virus of honeybees (Apis mellifera implicated in elevated colony mortality rates worldwide and facilitated through vector transmission by the ectoparasitic mite Varroa destructor. Clinical, symptomatic DWV infections are almost exclusively associated with high virus titres during pupal development, usually acquired through feeding by Varroa mites when reproducing on bee pupae. Control of the mite population, generally through acaricide treatment, is essential for breaking the DWV epidemic and minimizing colony losses. In this study, we evaluated the effectiveness of remedial mite control on clearing DWV from a colony. DWV titres in adult bees and pupae were monitored at 2 week intervals through summer and autumn in acaricide-treated and untreated colonies. The DWV titres in Apistan treated colonies was reduced 1000-fold relative to untreated colonies, which coincided with both the removal of mites and also a turnover of the bee population in the colony. This adult bee population turnover is probably more critical than previously realized for effective clearing of DWV infections. After this initial reduction, subclinical DWV titres persisted and even increased again gradually during autumn, demonstrating that alternative non-Varroa transmission routes can maintain the DWV titres at significant subclinical levels even after mite removal. The implications of these results for practical recommendations to mitigate deleterious subclinical DWV infections and improving honeybee health management are discussed.

El Amarilleo de las cucurbitáceas : diagnóstico y microscopía de las relaciones virus-planta y virus-vector

OpenAIRE

Rodrigo Villar, Gema

2002-01-01

L' ENGROGUIMENT DE LES CUCURBITÀCIES: DIAGNÓSTIC I MICROSCOPIA DE LES RELACIONS VIRUS-PLANTA I VIRUS-VECTOR La malaltia de l'engroguiment de les cucurbitàcies, de gran importància, en els cultius del sud-est espanyol, està produïda per dos Closteroviridae transmesos per mosques blanques, el virus del fals engroguiment de la remolatxa (BPYV) i el virus de l'engroguiment enanitzant de les cucurbitàcies (CYSDV). BPYV és transmès específicament i de forma semipersistent per Trialeurodes vaporario...

Dengue and Zika viruses: lessons learned from the similarities between these Aedes mosquito-vectored arboviruses.

Science.gov (United States)

Suwanmanee, San; Luplertlop, Natthanej

2017-02-01

The currently spreading arbovirus epidemic is having a severe impact on human health worldwide. The two most common flaviviruses, dengue virus (DENV) and Zika virus (ZIKV), are transmitted through the same viral vector, Aedes spp. mosquitoes. Since the discovery of DENV in 1943, this virus has been reported to cause around 390 million human infections per year, approximately 500,000 of which require hospitalization and over 20,000 of which are lethal. The present DENV epidemic is primarily concentrated in Southeast Asia. ZIKV, which was discovered in 1952, is another important arthropod-borne flavivirus. The neurotropic role of ZIKV has been reported in infected newborns with microcephaly and in adults with Guillain-Barre syndrome. Despite DENV and ZIKV sharing the same viral vector, their complex pathogenic natures are poorly understood, and the infections they cause do not have specific treatments or effective vaccines. Therefore, this review will describe what is currently known about the clinical characteristics, pathogenesis mechanisms, and transmission of these two viruses. Better understanding of the interrelationships between DENV and ZIKV will provide a useful perspective for developing an effective strategy for controlling both viruses in the future.

Serological indication for persistence of bovine respiratory syncytial virus in cattle and attempts to detect the virus

NARCIS (Netherlands)

Poel, van der W.H.M.; Langedijk, J.P.M.; Kramps, J.A.; Middel, W.G.J.; Brand, A.; Oirschot, van J.T.

1997-01-01

To identify putative persistent bovine respiratory syncytial virus (BRSV) infections in cattle, seven cattle that had experienced BRSV infections were treated with corticosteroids for two periods of 5 days. During the 5-day periods and the 3 weeks after treatment, attempts were made to isolate BRSV

Viral Determinants and Vector Competence of Zika Virus Transmission

Directory of Open Access Journals (Sweden)

Hong-Wai Tham

2018-05-01

Full Text Available Zika virus (ZIKV has emerged as a new global health threat. Since its first discovery in Zika forest in Uganda, this virus has been isolated from several mosquito species, including Aedes aegypti and Aedes albopictus. The geographical distribution of these mosquito species across tropical and subtropical regions has led to several outbreaks, including the recent pandemic in Brazil, followed by the Pacific islands and other areas of North and South America. This has gained attention of the scientific community to elucidate the epidemiology and transmission of ZIKV. Despite its strong attention on clinical aspects for healthcare professionals, the relationships between ZIKV and its principal vectors, A. aegypti and A. albopictus, have not gained substantial interest in the scientific research community. As such, this review aims to summarize the current knowledge on ZIKV tropism and some important mechanisms which may be employed by the virus for effective strategies on viral survival in mosquitoes. In addition, this review identifies the areas of research that should be placed attention to, for which to be exploited for novel mosquito control strategies.

Viral Determinants and Vector Competence of Zika Virus Transmission

Science.gov (United States)

Tham, Hong-Wai; Balasubramaniam, Vinod; Ooi, Man K.; Chew, Miaw-Fang

2018-01-01

Zika virus (ZIKV) has emerged as a new global health threat. Since its first discovery in Zika forest in Uganda, this virus has been isolated from several mosquito species, including Aedes aegypti and Aedes albopictus. The geographical distribution of these mosquito species across tropical and subtropical regions has led to several outbreaks, including the recent pandemic in Brazil, followed by the Pacific islands and other areas of North and South America. This has gained attention of the scientific community to elucidate the epidemiology and transmission of ZIKV. Despite its strong attention on clinical aspects for healthcare professionals, the relationships between ZIKV and its principal vectors, A. aegypti and A. albopictus, have not gained substantial interest in the scientific research community. As such, this review aims to summarize the current knowledge on ZIKV tropism and some important mechanisms which may be employed by the virus for effective strategies on viral survival in mosquitoes. In addition, this review identifies the areas of research that should be placed attention to, for which to be exploited for novel mosquito control strategies. PMID:29875751

O'nyong nyong virus molecular determinants of unique vector specificity reside in non-structural protein 3.

Directory of Open Access Journals (Sweden)

Kali D Saxton-Shaw

Full Text Available O'nyong nyong virus (ONNV and Chikungunya virus (CHIKV are two closely related alphaviruses with very different infection patterns in the mosquito, Anopheles gambiae. ONNV is the only alphavirus transmitted by anopheline mosquitoes, but specific molecular determinants of infection of this unique vector specificity remain unidentified. Fifteen distinct chimeric viruses were constructed to evaluate both structural and non-structural regions of the genome and infection patterns were determined through artificial infectious feeds in An. gambiae with each of these chimeras. Only one region, non-structural protein 3 (nsP3, was sufficient to up-regulate infection to rates similar to those seen with parental ONNV. When ONNV non-structural protein 3 (nsP3 replaced nsP3 from CHIKV virus in one of the chimeric viruses, infection rates in An. gambiae went from 0% to 63.5%. No other single gene or viral region addition was able to restore infection rates. Thus, we have shown that a non-structural genome element involved in viral replication is a major element involved in ONNV's unique vector specificity.

Persistence of hepatitis C virus in a white population: associations with human leukocyte antigen class 1.

LENUS (Irish Health Repository)

Fanning, Liam J

2012-02-03

The aim of this study was to define novel associations between human leukocyte antigen (HLA) class 1 alleles and persistence or clearance of the hepatitis C virus (HCV) in a white population. All individuals in the study were seropositive for anti-HCV antibodies. Viral status was determined by the Roche HCV Amplicor test. HLA-A, -B, -C allelic group profile was molecularly defined by reverse line probe hybridization. The strongest individual allelic group associations with persistent HCV infection were HLA A*11 (p = 0.044) and Cw*04 (p = 0.006). However, only the HLA C*04 association survived correction for multiple comparisons. Further analysis of alleles in linkage with HLA Cw*04 revealed that the haplotype HLA A*11, Cw*04 was present in 11 individuals, 10 of whom were viremic (p = 0.05). No gene dosage effect was observed. No association between HLA class 1 allelic groups and aviremia and virus load was evident in this white population. HLA B*44 is associated with low virus load in human immunodeficiency virus disease, but this association was not evident in this HCV-infected population. Novel HLA class 1 alleles associated with persistence of HCV have been identified.

A Respiratory Syncytial Virus Vaccine Vectored by a Stable Chimeric and Replication-Deficient Sendai Virus Protects Mice without Inducing Enhanced Disease.

Science.gov (United States)

Wiegand, Marian Alexander; Gori-Savellini, Gianni; Gandolfo, Claudia; Papa, Guido; Kaufmann, Christine; Felder, Eva; Ginori, Alessandro; Disanto, Maria Giulia; Spina, Donatella; Cusi, Maria Grazia

2017-05-15

Respiratory syncytial virus (RSV) is a major cause of severe respiratory infections in children and elderly people, and no marketed vaccine exists. In this study, we generated and analyzed a subunit vaccine against RSV based on a novel genome replication-deficient Sendai virus (SeV) vector. We inserted the RSV F protein, known to be a genetically stable antigen, into our vector in a specific way to optimize the vaccine features. By exchanging the ectodomain of the SeV F protein for its counterpart from RSV, we created a chimeric vectored vaccine that contains the RSV F protein as an essential structural component. In this way, the antigen is actively expressed on the surfaces of vaccine particles in its prefusion conformation, and as recently reported for other vectored vaccines, the occurrence of silencing mutations of the transgene in the vaccine genome can be prevented. In addition, its active gene expression contributes to further stimulation of the immune response. In order to understand the best route of immunization, we compared vaccine efficacies after intranasal (i.n.) or intramuscular (i.m.) immunization of BALB/c mice. Via both routes, substantial RSV-specific immune responses were induced, consisting of serum IgG and neutralizing antibodies, as well as cytotoxic T cells. Moreover, i.n. immunization was also able to stimulate specific mucosal IgA in the upper and lower respiratory tract. In virus challenge experiments, animals were protected against RSV infection after both i.n. and i.m. immunization without inducing vaccine-enhanced disease. Above all, the replication-deficient SeV appeared to be safe and well tolerated. IMPORTANCE Respiratory syncytial virus (RSV) is a major cause of respiratory diseases in young children and elderly people worldwide. There is a great demand for a licensed vaccine. Promising existing vaccine approaches based on live-attenuated vaccines or viral vectors have suffered from unforeseen drawbacks related to immunogenicity

Persistence and infectivity of Zika virus in semen after returning from endemic areas: Report of 5 cases.

Science.gov (United States)

García-Bujalance, S; Gutiérrez-Arroyo, A; De la Calle, F; Díaz-Menéndez, M; Arribas, Jose R; García-Rodríguez, J; Arsuaga, M

2017-11-01

There are limited data about the persistence and infectivity of Zika virus in semen of symptomatic travelers returning from endemic areas and even less data in asymptomatic cases. We investigated the persistence and infectivity of ZIKA virus in semen in five patients with Zika virus infection returning to Spain from endemic areas. We evaluated the epidemiological, clinical and virological characteristic of the five patients. In semen we detected ZIKA virus by PCR, partial sequencing and cell culture. We also performed phylogenetic analysis. We detected Zika virus RNA (Asian lineage) by PCR in semen samples from day 14th to day 96th since the day of illness onset. Semen viral culture was positive for Zika virus in two patients at days of illness 30 and 69 by virus propagation. Phylogenetic analysis strongly suggested male to female sexual transmission in a couple returning from Maldives. This case series confirms that Zika virus RNA can be detected in semen up to three months after infection. Viral culture of semen samples shows prolonged infectivity that can lead to sexual transmission of Zika virus. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantification of vector and host competence for Japanese encephalitis virus: a systematic review of the literature

Science.gov (United States)

Japanese encephalitis virus (JEV) is a virus of the Flavivirus genus that may result in encephalitis in human hosts. This vector-borne zoonosis occurs in Eastern and Southeastern Asia and an intentional or inadvertent introduction into the United States (US) will have major public health and economi...

[Activating effect of cyclophosphane at late stages of persistence of the tick-borne encephalitis virus].

Science.gov (United States)

Frolova, T V; Pogodina, V V; Larina, G I; Frolova, M P; Karmysheva, V Ia

1982-01-01

Conditions of activation of persistent infection caused by subcutaneous inoculation of Syrian hamsters with the B-383 and Vasilchenko strains of tick-borne encephalitis virus (TBE) were studied. After 2 administrations of cyclophosphane (CP) on day 170 of infection clinically manifest disease developed in some animals with increasingly severe pathomorphological lesions in the CNS. Several variants of activated TBE virus were isolated from brains and spleens of CP-treated hamsters. The activation of persistent infection was observed in the presence of marked decreased of humoral immunity level, weight of the thymus, and values of spontaneous rosette-formation.

Adeno-associated virus Rep-mediated targeting of integrase-defective retroviral vector DNA circles into human chromosome 19

International Nuclear Information System (INIS)

Huang, Shuohao; Kawabe, Yoshinori; Ito, Akira; Kamihira, Masamichi

2012-01-01

Highlights: ► Adeno-associated virus (AAV) is capable of targeted integration in human cells. ► Integrase-defective retroviral vector (IDRV) enables a circular DNA delivery. ► A targeted integration system of IDRV DNA using the AAV integration mechanism. ► Targeted IDRV integration ameliorates the safety concerns for retroviral vectors. -- Abstract: Retroviral vectors have been employed in clinical trials for gene therapy owing to their relative large packaging capacity, alterable cell tropism, and chromosomal integration for stable transgene expression. However, uncontrollable integrations of transgenes are likely to cause safety issues, such as insertional mutagenesis. A targeted transgene integration system for retroviral vectors, therefore, is a straightforward way to address the insertional mutagenesis issue. Adeno-associated virus (AAV) is the only known virus capable of targeted integration in human cells. In the presence of AAV Rep proteins, plasmids possessing the p5 integration efficiency element (p5IEE) can be integrated into the AAV integration site (AAVS1) in the human genome. In this report, we describe a system that can target the circular DNA derived from non-integrating retroviral vectors to the AAVS1 site by utilizing the Rep/p5IEE integration mechanism. Our results showed that after G418 selection 30% of collected clones had retroviral DNA targeted at the AAVS1 site.

Adeno-associated virus vector-mediated transduction in the cat brain.

Science.gov (United States)

Vite, Charles H; Passini, Marco A; Haskins, Mark E; Wolfe, John H

2003-10-01

Adeno-associated virus (AAV) vectors are capable of delivering a therapeutic gene to the mouse brain that can result in long-term and widespread protein production. However, the human infant brain is more than 1000 times larger than the mouse brain, which will make the treatment of global neurometabolic disorders in children more difficult. In this study, we evaluated the ability of three AAV serotypes (1,2, and 5) to transduce cells in the cat brain as a model of a large mammalian brain. The human lysosomal enzyme beta-glucuronidase (GUSB) was used as a reporter gene, because it can be distinguished from feline GUSB by heat stability. The vectors were injected into the cerebral cortex, caudate nucleus, thalamus, corona radiata, internal capsule, and centrum semiovale of 8-week-old cats. The brains were evaluated for gene expression using in situ hybridization and enzyme histochemistry 10 weeks after surgery. The AAV2 vector was capable of transducing cells in the gray matter, while the AAV1 vector resulted in greater transduction of the gray matter than AAV2 as well as transduction of the white matter. AAV5 did not result in detectable transduction in the cat brain.

A simple, rapid and inexpensive method for localization of Tomato yellow leaf curl virus and Potato leafroll virus in plant and insect vectors.

Science.gov (United States)

Ghanim, Murad; Brumin, Marina; Popovski, Smadar

2009-08-01

A simple, rapid, inexpensive method for the localization of virus transcripts in plant and insect vector tissues is reported here. The method based on fluorescent in situ hybridization using short DNA oligonucleotides complementary to an RNA segment representing a virus transcript in the infected plant or insect vector. The DNA probe harbors a fluorescent molecule at its 5' or 3' ends. The protocol: simple fixation, hybridization, minimal washing and confocal microscopy, provides a highly specific signal. The reliability of the protocol was tested by localizing two phloem-limited plant virus transcripts in infected plants and insect tissues: Tomato yellow leaf curl virus (TYLCV) (Begomovirus: Geminiviridae), exclusively transmitted by the whitefly Bemisia tabaci (Gennadius) in a circulative non-propagative manner, and Potato leafroll virus (Polerovirus: Luteoviridae), similarly transmitted by the aphid Myzus persicae (Sulzer). Transcripts for both viruses were localized specifically to the phloem sieve elements of infected plants, while negative controls showed no signal. TYLCV transcripts were also localized to the digestive tract of B. tabaci, confirming TYLCV route of transmission. Compared to previous methods for localizing virus transcripts in plant and insect tissues that include complex steps for in-vitro probe preparation or antibody raising, tissue fixation, block preparation, sectioning and hybridization, the method described below provides very reliable, convincing, background-free results with much less time, effort and cost.

Persistence of foot-and mouth disease virus in ruminants

DEFF Research Database (Denmark)

Stenfeldt, Carolina; Belsham, Graham; Tjørnehøj, Kirsten

squamous epithelia of the coronary bands and oral cavity within a few days of infection. Viremia occurs within 2-3 days of infection, but is rapidly cleared through the effect of circulating antibodies of the adaptive immune response. The host response involves initial activation of the innate immune...... response, with activation and recruitment of effector-cells, and subsequent activation of T- and B-cells, leading to the production of circulating antibodies, as well as activation of cytotoxic T-cells. In ruminants, approximately 50% of animals infected with FMDV develop into persistently infected carrier...... animals, with intermittent excretion of live virus, whilst remaining animals clear the infection effectively. Previous experiments have indicated that the site of persistent viral replication is located in pharyngeal lymphoid tissue, as well as the basal epithelia of the dorsal soft palate...

[Construction and selection of effective mouse Smad6 recombinant lenti-virus interference vectors].

Science.gov (United States)

Yu, Jing; Qi, Mengchun; Deng, Jiupeng; Liu, Gang; Chen, Huaiqing

2010-10-01

This experiment was designed to construct mouse Smad6 recombinant RNA interference vectors and determine their interference effects on bone marrow mesenchymal stem cells (BMSCs). Three recombinant Smad6 RNA interference vectors were constructed by molecular clone techniques with a lenti-virus vector expressing green fluorescent protein (GFP), and the correctness of recombinant vectors was verified by DNA sequencing. Mouse BMSCs were used for transfection experiments and BMP-2 was in use for osteogenic induction of MSCs. The transfection efficiency of recombinant vectors was examined by Laser confocal scanning microscope and the interference effect of recombinant vectors on Smad6 gene expression was determined by real-time RT-PCR and Western blot, respectively. Three Smad6 recombinant RNA interference vectors were successfully constructed and their correctness was proved by DNA sequencing. After transfection, GFPs were effectively expressed in MSCs and all of three recombinant vectors gained high transfection efficiency (> 95%). Both real-time PCR and Western blot examination indicated that among three recombinant vectors, No. 2 Svector had the best interference effect and the interference effect was nearly 91% at protein level. In conclusion, Mouse recombinant Smad6 RNA interference (RNAi) vector was successfully constructed and it provided an effective tool for further studies on BMP signal pathways.

Fowl adenovirus serotype 9 vectored vaccine for protection of avian influenza virus

Science.gov (United States)

A fowl adenovirus serotype 9, a non-pathogenic large double stranded DNA virus, was developed as a viral vector to express influenza genes as a potential vaccine. Two separate constructs were developed that expressed either the hemagglutinin gene of A/Chicken/Jalisco/2012 (H7) or A/ Chicken/Iowa/20...

Herpes simplex virus vectors overexpressing the glucose transporter gene protect against seizure-induced neuron loss.

OpenAIRE

Lawrence, M S; Ho, D Y; Dash, R; Sapolsky, R M

1995-01-01

We have generated herpes simplex virus (HSV) vectors vIE1GT and v alpha 4GT bearing the GLUT-1 isoform of the rat brain glucose transporter (GT) under the control of the human cytomegalovirus ie1 and HSV alpha 4 promoters, respectively. We previously reported that such vectors enhance glucose uptake in hippocampal cultures and the hippocampus. In this study we demonstrate that such vectors can maintain neuronal metabolism and reduce the extent of neuron loss in cultures after a period of hypo...

Diversity of viruses in Ixodes ricinus, and characterization of a neurotropic strain of Eyach virus.

Science.gov (United States)

Moutailler, S; Popovici, I; Devillers, E; Vayssier-Taussat, M; Eloit, M

2016-05-01

Ticks transmit more pathogens-including bacteria, parasites and viruses-than any other arthropod vector. Although the epidemiological status of many tick-borne bacteria is very well characterized, tick-borne viruses are still relatively under-studied. Recently, several novel tick-borne viruses have been isolated from human febrile illnesses following tick bites, indicating the existence of other potential new and unknown tick-borne viruses. We used high-throughput sequencing to analyse the virome of Ixodes ricinus, the main vector of tick-borne pathogens in Europe. The majority of collected viral sequences were assigned to two potentially novel Nairovirus and Phlebovirus viruses, with prevalence rates ranging from 3.95% to 23.88% in adults and estimated to be between 0.14% and 72.16% in nymphs. These viruses could not be isolated from the brains of inoculated immunocompromised mice, perhaps indicating that they are unable to infect vertebrates. Within the I. ricinus virome, we also identified contigs with >90% identity to the known Eyach virus. Initially isolated in the 1980s, this virus was indirectly associated with human disease, but had never been extensively studied. Eyach virus prevalence varied between 0.07% and 5.26% in ticks from the French Ardennes and Alsace regions. Eyach virus was successfully isolated following intracerebral inoculation of immunocompromised mice with Eyach virus-positive tick extracts. This virus was also able to multiply and persist in the blood of immunocompetent mice inoculated by intraperitoneal injection, and caused brain infections in three of nine juveniles, without any obvious deleterious effects.

European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus.

Directory of Open Access Journals (Sweden)

Mélissanne de Wispelaere

2017-01-01

Full Text Available Japanese encephalitis virus (JEV is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5.After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease.In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds.

Diversity of viruses in Ixodes ricinus, and characterization of a neurotropic strain of Eyach virus

Directory of Open Access Journals (Sweden)

S. Moutailler

2016-05-01

Full Text Available Ticks transmit more pathogens—including bacteria, parasites and viruses—than any other arthropod vector. Although the epidemiological status of many tick-borne bacteria is very well characterized, tick-borne viruses are still relatively under-studied. Recently, several novel tick-borne viruses have been isolated from human febrile illnesses following tick bites, indicating the existence of other potential new and unknown tick-borne viruses. We used high-throughput sequencing to analyse the virome of Ixodes ricinus, the main vector of tick-borne pathogens in Europe. The majority of collected viral sequences were assigned to two potentially novel Nairovirus and Phlebovirus viruses, with prevalence rates ranging from 3.95% to 23.88% in adults and estimated to be between 0.14% and 72.16% in nymphs. These viruses could not be isolated from the brains of inoculated immunocompromised mice, perhaps indicating that they are unable to infect vertebrates. Within the I. ricinus virome, we also identified contigs with >90% identity to the known Eyach virus. Initially isolated in the 1980s, this virus was indirectly associated with human disease, but had never been extensively studied. Eyach virus prevalence varied between 0.07% and 5.26% in ticks from the French Ardennes and Alsace regions. Eyach virus was successfully isolated following intracerebral inoculation of immunocompromised mice with Eyach virus-positive tick extracts. This virus was also able to multiply and persist in the blood of immunocompetent mice inoculated by intraperitoneal injection, and caused brain infections in three of nine juveniles, without any obvious deleterious effects.

Environmental and biological factors influencing Culex pipiens quinquefasciatus Say (Diptera: Culicidae) vector competence for Saint Louis encephalitis virus.

Science.gov (United States)

Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra; Tabachnick, Walter J

2009-08-01

Complex interactions between environmental and biological factors influence the susceptibility of Culex pipiens quinquefasciatus to St. Louis encephalitis virus and could affect the epidemiology of virus transmission. Similar interactions could have epidemiologic implications for other vector-virus systems. We conducted an experiment to examine four such factors in combination: mosquito age, extrinsic incubation temperature (EIT), virus dose, and colony. The proportion of mosquitoes with body infections or disseminated infections varied between colonies, and was dependant on age, EIT, and dose. We also show that the probability of a body or leg infection interacted in complex ways between colonies, ages, EITs, and doses. The complex interactive effects of environmental and biological factors must be taken into account for studies of vector competence and epidemiology, especially when laboratory studies are used to generalize to natural transmission dynamics where the extent of variation is largely unknown.

Unrestricted Hepatocyte Transduction with Adeno-Associated Virus Serotype 8 Vectors in Mice

Science.gov (United States)

Nakai, Hiroyuki; Fuess, Sally; Storm, Theresa A.; Muramatsu, Shin-ichi; Nara, Yuko; Kay, Mark A.

2005-01-01

Recombinant adeno-associated virus (rAAV) vectors can mediate long-term stable transduction in various target tissues. However, with rAAV serotype 2 (rAAV2) vectors, liver transduction is confined to only a small portion of hepatocytes even after administration of extremely high vector doses. In order to investigate whether rAAV vectors of other serotypes exhibit similar restricted liver transduction, we performed a dose-response study by injecting mice with β-galactosidase-expressing rAAV1 and rAAV8 vectors via the portal vein. The rAAV1 vector showed a blunted dose-response similar to that of rAAV2 at high doses, while the rAAV8 vector dose-response remained unchanged at any dose and ultimately could transduce all the hepatocytes at a dose of 7.2 × 1012 vector genomes/mouse without toxicity. This indicates that all hepatocytes have the ability to process incoming single-stranded vector genomes into duplex DNA. A single tail vein injection of the rAAV8 vector was as efficient as portal vein injection at any dose. In addition, intravascular administration of the rAAV8 vector at a high dose transduced all the skeletal muscles throughout the body, including the diaphragm, the entire cardiac muscle, and substantial numbers of cells in the pancreas, smooth muscles, and brain. Thus, rAAV8 is a robust vector for gene transfer to the liver and provides a promising research tool for delivering genes to various target organs. In addition, the rAAV8 vector may offer a potential therapeutic agent for various diseases affecting nonhepatic tissues, but great caution is required for vector spillover and tight control of tissue-specific gene expression. PMID:15596817

Eilat virus displays a narrow mosquito vector range.

Science.gov (United States)

Nasar, Farooq; Haddow, Andrew D; Tesh, Robert B; Weaver, Scott C

2014-12-17

Most alphaviruses are arthropod-borne and utilize mosquitoes as vectors for transmission to susceptible vertebrate hosts. This ability to infect both mosquitoes and vertebrates is essential for maintenance of most alphaviruses in nature. A recently characterized alphavirus, Eilat virus (EILV), isolated from a pool of Anopheles coustani s.I. is unable to replicate in vertebrate cell lines. The EILV host range restriction occurs at both attachment/entry as well as genomic RNA replication levels. Here we investigated the mosquito vector range of EILV in species encompassing three genera that are responsible for maintenance of other alphaviruses in nature. Susceptibility studies were performed in four mosquito species: Aedes albopictus, A. aegypti, Anopheles gambiae, and Culex quinquefasciatus via intrathoracic and oral routes utilizing EILV and EILV expressing red fluorescent protein (-eRFP) clones. EILV-eRFP was injected at 10(7) PFU/mL to visualize replication in various mosquito organs at 7 days post-infection. Mosquitoes were also injected with EILV at 10(4)-10(1) PFU/mosquito and virus replication was measured via plaque assays at day 7 post-infection. Lastly, mosquitoes were provided bloodmeals containing EILV-eRFP at doses of 10(9), 10(7), 10(5) PFU/mL, and infection and dissemination rates were determined at 14 days post-infection. All four species were susceptible via the intrathoracic route; however, replication was 10-100 fold less than typical for most alphaviruses, and infection was limited to midgut-associated muscle tissue and salivary glands. A. albopictus was refractory to oral infection, while A. gambiae and C. quinquefasciatus were susceptible only at 10(9) PFU/mL dose. In contrast, A. aegypti was susceptible at both 10(9) and 10(7) PFU/mL doses, with body infection rates of 78% and 63%, and dissemination rates of 26% and 8%, respectively. The exclusion of vertebrates in its maintenance cycle may have facilitated the adaptation of EILV to a single

Vectors, hosts, and control measures for Zika virus in the Americas

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Thompson, Sarah J.; Pearce, John; Ramey, Andy M.

2017-01-01

We examine Zika virus (ZIKV) from an ecological perspective and with a focus on the Americas. We assess (1) the role of wildlife in ZIKV disease ecology, (2) how mosquito behavior and biology influence disease dynamics, and (3) how nontarget species and ecosystems may be impacted by vector control programs. Our review suggests that free-ranging, non-human primates may be involved in ZIKV transmission in the Old World; however, other wildlife species likely play a limited role in maintaining or transmitting ZIKV. In the Americas, a zoonotic cycle has not yet been definitively established. Understanding behaviors and habitat tolerances of Aedes aegypti and Aedes albopictus, two ZIKV competent vectors in the Americas, will allow more accurate modeling of disease spread and facilitate targeted and effective control efforts. Vector control efforts may have direct and indirect impacts to wildlife, particularly invertebrate feeding species; however, strategies could be implemented to limit detrimental ecological effects.

Immunogenicity in African Green Monkeys of M Protein Mutant Vesicular Stomatitis Virus Vectors and Contribution of Vector-Encoded Flagellin

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Marlena M. Westcott

2018-03-01

Full Text Available Recombinant vesicular stomatitis virus (VSV is a promising platform for vaccine development. M51R VSV, an attenuated, M protein mutant strain, is an effective inducer of Type I interferon and dendritic cell (DC maturation, which are desirable properties to exploit for vaccine design. We have previously evaluated M51R VSV (M51R and M51R VSV that produces flagellin (M51R-F as vaccine vectors using murine models, and found that flagellin enhanced DC activation and VSV-specific antibody production after low-dose vaccination. In this report, the immunogenicity of M51R vectors and the adjuvant effect of virus-produced flagellin were evaluated in nonhuman primates following high-dose (108 pfu and low-dose (105 pfu vaccination. A single intramuscular vaccination of African green monkeys with M51R or M51R-F induced VSV-specific, dose-dependent humoral immune responses. Flagellin induced a significant increase in antibody production (IgM, IgG and neutralizing antibody at the low vaccination dose. A VSV-specific cellular response was detected at 6 weeks post-vaccination, but was neither dose-dependent nor enhanced by flagellin; similar numbers of VSV-specific, IFNγ-producing cells were detected in lymph node and spleen of all animals. These results indicate that virus-directed, intracellular flagellin production may improve VSV-based vaccines encoding heterologous antigens by lowering the dose required to achieve humoral immunity.

Small Interfering RNA Pathway Modulates Initial Viral Infection in Midgut Epithelium of Insect after Ingestion of Virus.

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Lan, Hanhong; Chen, Hongyan; Liu, Yuyan; Jiang, Chaoyang; Mao, Qianzhuo; Jia, Dongsheng; Chen, Qian; Wei, Taiyun

2016-01-15

Numerous viruses are transmitted in a persistent manner by insect vectors. Persistent viruses establish their initial infection in the midgut epithelium, from where they disseminate to the midgut visceral muscles. Although propagation of viruses in insect vectors can be controlled by the small interfering RNA (siRNA) antiviral pathway, whether the siRNA pathway can control viral dissemination from the midgut epithelium is unknown. Infection by a rice virus (Southern rice black streaked dwarf virus [SRBSDV]) of its incompetent vector (the small brown planthopper [SBPH]) is restricted to the midgut epithelium. Here, we show that the siRNA pathway is triggered by SRBSDV infection in continuously cultured cells derived from the SBPH and in the midgut of the intact insect. Knockdown of the expression of the core component Dicer-2 of the siRNA pathway by RNA interference strongly increased the ability of SRBSDV to propagate in continuously cultured SBPH cells and in the midgut epithelium, allowing viral titers in the midgut epithelium to reach the threshold (1.99 × 10(9) copies of the SRBSDV P10 gene/μg of midgut RNA) needed for viral dissemination into the SBPH midgut muscles. Our results thus represent the first elucidation of the threshold for viral dissemination from the insect midgut epithelium. Silencing of Dicer-2 further facilitated the transmission of SRBSDV into rice plants by SBPHs. Taken together, our results reveal the new finding that the siRNA pathway can control the initial infection of the insect midgut epithelium by a virus, which finally affects the competence of the virus's vector. Many viral pathogens that cause significant global health and agricultural problems are transmitted via insect vectors. The first bottleneck in viral infection, the midgut epithelium, is a principal determinant of the ability of an insect species to transmit a virus. Southern rice black streaked dwarf virus (SRBSDV) is restricted exclusively to the midgut epithelium of an

Adeno-Associated Virus Vectors and Stem Cells: Friends or Foes?

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Brown, Nolan; Song, Liujiang; Kollu, Nageswara R; Hirsch, Matthew L

2017-06-01

The infusion of healthy stem cells into a patient-termed "stem-cell therapy"-has shown great promise for the treatment of genetic and non-genetic diseases, including mucopolysaccharidosis type 1, Parkinson's disease, multiple sclerosis, numerous immunodeficiency disorders, and aplastic anemia. Stem cells for cell therapy can be collected from the patient (autologous) or collected from another "healthy" individual (allogeneic). The use of allogenic stem cells is accompanied with the potentially fatal risk that the transplanted donor T cells will reject the patient's cells-a process termed "graft-versus-host disease." Therefore, the use of autologous stem cells is preferred, at least from the immunological perspective. However, an obvious drawback is that inherently as "self," they contain the disease mutation. As such, autologous cells for use in cell therapies often require genetic "correction" (i.e., gene addition or editing) prior to cell infusion and therefore the requirement for some form of nucleic acid delivery, which sets the stage for the AAV controversy discussed herein. Despite being the most clinically applied gene delivery context to date, unlike other more concerning integrating and non-integrating vectors such as retroviruses and adenovirus, those based on adeno-associated virus (AAV) have not been employed in the clinic. Furthermore, published data regarding AAV vector transduction of stem cells are inconsistent in regards to vector transduction efficiency, while the pendulum swings far in the other direction with demonstrations of AAV vector-induced toxicity in undifferentiated cells. The variation present in the literature examining the transduction efficiency of AAV vectors in stem cells may be due to numerous factors, including inconsistencies in stem-cell collection, cell culture, vector preparation, and/or transduction conditions. This review summarizes the controversy surrounding AAV vector transduction of stem cells, hopefully setting the

Beet necrotic yellow vein virus accumulates inside resting spores and zoosporangia of its vector Polymyxa betae BNYVV infects P. betae

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Payton Mark

2007-04-01

Full Text Available Abstract Background Plasmodiophorids and chytrids are zoosporic parasites of algae and land plant and are distributed worldwide. There are 35 species belonging to the order Plasmodiophorales and three species, Polymyxa betae, P. graminis, and Spongospora subterranea, are plant viral vectors. Plasmodiophorid transmitted viruses are positive strand RNA viruses belonging to five genera. Beet necrotic yellow vein virus (BNYVV and its vector, P. betae, are the causal agents for rhizomania. Results Evidence of BNYVV replication and movement proteins associating with P. betae resting spores was initially obtained using immunofluorescence labeling and well characterized antisera to each of the BNYVV proteins. Root cross sections were further examined using immunogold labeling and electron microscopy. BNYVV proteins translated from each of the four genomic and subgenomic RNAs accumulate inside P. betae resting spores and zoospores. Statistical analysis was used to determine if immunolabelling detected viral proteins in specific subcellular domains and at a level greater than in control samples. Conclusion Virus-like particles were detected in zoosporangia. Association of BNYVV replication and movement proteins with sporangial and sporogenic stages of P. betae suggest that BNYVV resides inside its vector during more than one life cycle stage. These data suggest that P. betae might be a host as well as a vector for BNYVV

Beet necrotic yellow vein virus accumulates inside resting spores and zoosporangia of its vector Polymyxa betae BNYVV infects P. betae.

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Lubicz, Jeanmarie Verchot; Rush, Charles M; Payton, Mark; Colberg, Terry

2007-04-05

Plasmodiophorids and chytrids are zoosporic parasites of algae and land plant and are distributed worldwide. There are 35 species belonging to the order Plasmodiophorales and three species, Polymyxa betae, P. graminis, and Spongospora subterranea, are plant viral vectors. Plasmodiophorid transmitted viruses are positive strand RNA viruses belonging to five genera. Beet necrotic yellow vein virus (BNYVV) and its vector, P. betae, are the causal agents for rhizomania. Evidence of BNYVV replication and movement proteins associating with P. betae resting spores was initially obtained using immunofluorescence labeling and well characterized antisera to each of the BNYVV proteins. Root cross sections were further examined using immunogold labeling and electron microscopy. BNYVV proteins translated from each of the four genomic and subgenomic RNAs accumulate inside P. betae resting spores and zoospores. Statistical analysis was used to determine if immunolabelling detected viral proteins in specific subcellular domains and at a level greater than in control samples. Virus-like particles were detected in zoosporangia. Association of BNYVV replication and movement proteins with sporangial and sporogenic stages of P. betae suggest that BNYVV resides inside its vector during more than one life cycle stage. These data suggest that P. betae might be a host as well as a vector for BNYVV.

Zika virus infection: Past and present of another emerging vector-borne disease.

Science.gov (United States)

Sakkas, Hercules; Economou, Vangelis; Papadopoulou, Chrissanthy

2016-01-01

Zika virus infection is an emerging mosquito-borne disease, first identified in Uganda in 1947. It is caused by the Zika arbovirus, and transmitted by the bites of infected mosquitoes of the genus Aedes. For almost half a century, the Zika virus was reported as the causative agent of sporadic human infections. In 2007, the Zika virus emerged outside Asia and Africa causing an epidemic on the Island of Yap in Micronesia. The manifestation of the newly acquired human infection varies from asymptomatic to self-limiting acute febrile illness with symptoms and clinical features similar to those caused by the Dengue virus ('Dengue-like syndrome'). The real-time PCR and serological methods have been successfully applied for the diagnosis of the disease. The treatment is symptomatic, since there is no specific antiviral treatment or a vaccine. During the recent outbreaks in French Polynesia and Brazil, incidents of Guillain-Barrι syndrome and microcephaly were associated with Zika virus infection, giving rise to fears of further global spread of the virus. Prevention and vector control strategies have to be urgently implemented by national health authorities in order to contain future outbreaks in vulnerable populations. This review summarizes the existing information on Zika virus characteristics, pathogenesis and epidemiology, the available methods for the diagnosis of Zika virus infection and recent approaches for prevention and control.

Utilization of a tobacco rattle virus vector to clone an Nicotiana benthamiana cDNA library for VIGS

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Virus-induced gene silencing (VIGS) is an efficient and rapid method to identify plant gene functions. One of the most widely used VIGS vectors is Tobacco rattle virus (TRV) which has been used successfully for RNA interference (RNAi) in N. benthamiana and tomato. We previously modified a TRV VIGS v...

The NSs protein of tomato spotted wilt virus is required for persistent infection and transmission by Frankliniella occidentalis.

Science.gov (United States)

Margaria, P; Bosco, L; Vallino, M; Ciuffo, M; Mautino, G C; Tavella, L; Turina, M

2014-05-01

Tomato spotted wilt virus (TSWV) is the type member of tospoviruses (genus Tospovirus), plant-infecting viruses that cause severe damage to ornamental and vegetable crops. Tospoviruses are transmitted by thrips in the circulative propagative mode. We generated a collection of NSs-defective TSWV isolates and showed that TSWV coding for truncated NSs protein could not be transmitted by Frankliniella occidentalis. Quantitative reverse transcription (RT)-PCR and immunostaining of individual insects detected the mutant virus in second-instar larvae and adult insects, demonstrating that insects could acquire and accumulate the NSs-defective virus. Nevertheless, adults carried a significantly lower viral load, resulting in the absence of transmission. Genome sequencing and analyses of reassortant isolates showed genetic evidence of the association between the loss of competence in transmission and the mutation in the NSs coding sequence. Our findings offer new insight into the TSWV-thrips interaction and Tospovirus pathogenesis and highlight, for the first time in the Bunyaviridae family, a major role for the S segment, and specifically for the NSs protein, in virulence and efficient infection in insect vector individuals. Our work is the first to show a role for the NSs protein in virus accumulation in the insect vector in the Bunyaviridae family: demonstration was obtained for the system TSWV-F. occidentalis, arguably one of the most damaging combination for vegetable crops. Genetic evidence of the involvement of the NSs protein in vector transmission was provided with multiple approaches.

Aedes-Borne Virus-Mosquito Interactions: Mass Spectrometry Strategies and Findings.

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Pando-Robles, Victoria; Batista, Cesar V

2017-06-01

Aedes-borne viruses are responsible for high-impact neglected tropical diseases and unpredictable outbreaks such as the ongoing Zika epidemics. Aedes mosquitoes spread different arboviruses such as Dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus, among others, and are responsible for the continuous emergence and reemergence of these pathogens. These viruses have complex transmission cycles that include two hosts, namely the Aedes mosquito as a vector and susceptible vertebrate hosts. Human infection with arboviruses causes diseases that range from subclinical or mild to febrile diseases, encephalitis, and hemorrhagic fever. Infected mosquitoes do not show detectable signs of disease, even though the virus maintains a lifelong persistent infection. The infection of the Aedes mosquito by viruses involves a molecular crosstalk between cell and viral proteins. An understanding of how mosquito vectors and viruses interact is of fundamental interest, and it also offers novel perspectives for disease control. In recent years, mass spectrometry (MS)-based strategies in combination with bioinformatics have been successfully applied to identify and quantify global changes in cellular proteins, lipids, peptides, and metabolites in response to viral infection. Although the information about proteomics in the Aedes mosquito is limited, the information that has been reported can set up the basis for future studies. This review reflects how MS-based approaches have extended our understanding of Aedes mosquito biology and the development of DENV and CHIKV infection in the vector. Finally, this review discusses future challenges in the field.

Characterization of a Brome mosaic virus strain and its use as a vector for gene silencing in monocotyledonous hosts.

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Ding, Xin Shun; Schneider, William L; Chaluvadi, Srinivasa Rao; Mian, M A Rouf; Nelson, Richard S

2006-11-01

Virus-induced gene silencing (VIGS) is used to analyze gene function in dicotyledonous plants but less so in monocotyledonous plants (particularly rice and corn), partially due to the limited number of virus expression vectors available. Here, we report the cloning and modification for VIGS of a virus from Festuca arundinacea Schreb. (tall fescue) that caused systemic mosaic symptoms on barley, rice, and a specific cultivar of maize (Va35) under greenhouse conditions. Through sequencing, the virus was determined to be a strain of Brome mosaic virus (BMV). The virus was named F-BMV (F for Festuca), and genetic determinants that controlled the systemic infection of rice were mapped to RNAs 1 and 2 of the tripartite genome. cDNA from RNA 3 of the Russian strain of BMV (R-BMV) was modified to accept inserts from foreign genes. Coinoculation of RNAs 1 and 2 from F-BMV and RNA 3 from R-BMV expressing a portion of a plant gene to leaves of barley, rice, and maize plants resulted in visual silencing-like phenotypes. The visual phenotypes were correlated with decreased target host transcript levels in the corresponding leaves. The VIGS visual phenotype varied from maintained during silencing of actin 1 transcript expression to transient with incomplete penetration through affected tissue during silencing of phytoene desaturase expression. F-BMV RNA 3 was modified to allow greater accumulation of virus while minimizing virus pathogenicity. The modified vector C-BMV(A/G) (C for chimeric) was shown to be useful for VIGS. These BMV vectors will be useful for analysis of gene function in rice and maize for which no VIGS system is reported.

A paramyxovirus-vectored intranasal vaccine against Ebola virus is immunogenic in vector-immune animals.

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Yang, Lijuan; Sanchez, Anthony; Ward, Jerrold M; Murphy, Brian R; Collins, Peter L; Bukreyev, Alexander

2008-08-01

Ebola virus (EBOV) causes outbreaks of a highly lethal hemorrhagic fever in humans. The virus can be transmitted by direct contact as well as by aerosol and is considered a potential bioweapon. Because direct immunization of the respiratory tract should be particularly effective against infection of mucosal surfaces, we previously developed an intranasal vaccine based on replication-competent human parainfluenza virus type 3 (HPIV3) expressing EBOV glycoprotein GP (HPIV3/EboGP) and showed that it is immunogenic and protective against a high dose parenteral EBOV challenge. However, because the adult human population has considerable immunity to HPIV3, which is a common human pathogen, replication and immunogenicity of the vaccine in this population might be greatly restricted. Indeed, in the present study, replication of the vaccine in the respiratory tract of HPIV3-immune guinea pigs was found to be restricted to undetectable levels. This restriction appeared to be based on both neutralizing antibodies and cellular or other components of the immunity to HPIV3. Surprisingly, even though replication of HPIV3/EboGP was highly restricted in HPIV3-immune animals, it induced a high level of EBOV-specific antibodies that nearly equaled that obtained in HPIV3-naive animals. We also show that the previously demonstrated presence of functional GP in the vector particle was not associated with increased replication in the respiratory tract nor with spread beyond the respiratory tract of HPIV3-naive guinea pigs, indicating that expression and functional incorporation of the attachment/penetration glycoprotein of this systemic virus did not mediate a change in tissue tropism.

Alteration of intersubunit acid–base pair interactions at the quasi-threefold axis of symmetry of Cucumber mosaic virus disrupts aphid vector transmission

International Nuclear Information System (INIS)

Bricault, Christine A.; Perry, Keith L.

2013-01-01

In the atomic model of Cucumber mosaic virus (CMV), six amino acid residues form stabilizing salt bridges between subunits of the asymmetric unit at the quasi-threefold axis of symmetry. To evaluate the effects of these positions on virion stability and aphid vector transmissibility, six charged amino acid residues were individually mutated to alanine. All of the six engineered viruses were viable and exhibited near wild type levels of virion stability in the presence of urea. Aphid vector transmissibility was nearly or completely eliminated in the case of four of the mutants; two mutants demonstrated intermediate aphid transmissibility. For the majority of the engineered mutants, second-site mutations were observed following aphid transmission and/or mechanical passaging, and one restored transmission rates to that of the wild type. CMV capsids tolerate disruption of acid–base pairing interactions at the quasi-threefold axis of symmetry, but these interactions are essential for maintaining aphid vector transmissibility. - Highlights: ► Amino acids between structural subunits of Cucumber mosaic virus affect vector transmission. ► Mutant structural stability was retained, while aphid vector transmissibility was disrupted. ► Spontaneous, second-site mutations restored aphid vector transmissibility

Alteration of intersubunit acid–base pair interactions at the quasi-threefold axis of symmetry of Cucumber mosaic virus disrupts aphid vector transmission

Energy Technology Data Exchange (ETDEWEB)

Bricault, Christine A. [Department of Plant Pathology and Plant-Microbe Biology, 334 Plant Science Building, Cornell University, Ithaca, NY 14850 (United States); Perry, Keith L., E-mail: KLP3@cornell.edu [Department of Plant Pathology and Plant-Microbe Biology, 334 Plant Science Building, Cornell University, Ithaca, NY 14850 (United States)

2013-06-05

In the atomic model of Cucumber mosaic virus (CMV), six amino acid residues form stabilizing salt bridges between subunits of the asymmetric unit at the quasi-threefold axis of symmetry. To evaluate the effects of these positions on virion stability and aphid vector transmissibility, six charged amino acid residues were individually mutated to alanine. All of the six engineered viruses were viable and exhibited near wild type levels of virion stability in the presence of urea. Aphid vector transmissibility was nearly or completely eliminated in the case of four of the mutants; two mutants demonstrated intermediate aphid transmissibility. For the majority of the engineered mutants, second-site mutations were observed following aphid transmission and/or mechanical passaging, and one restored transmission rates to that of the wild type. CMV capsids tolerate disruption of acid–base pairing interactions at the quasi-threefold axis of symmetry, but these interactions are essential for maintaining aphid vector transmissibility. - Highlights: ► Amino acids between structural subunits of Cucumber mosaic virus affect vector transmission. ► Mutant structural stability was retained, while aphid vector transmissibility was disrupted. ► Spontaneous, second-site mutations restored aphid vector transmissibility.

An Epstein-Barr virus encoded inhibitor of Colony Stimulating Factor-1 signaling is an important determinant for acute and persistent EBV infection.

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Makoto Ohashi

2012-12-01

Full Text Available Acute Epstein-Barr virus (EBV infection is the most common cause of Infectious Mononucleosis. Nearly all adult humans harbor life-long, persistent EBV infection which can lead to development of cancers including Hodgkin Lymphoma, Burkitt Lymphoma, nasopharyngeal carcinoma, gastric carcinoma, and lymphomas in immunosuppressed patients. BARF1 is an EBV replication-associated, secreted protein that blocks Colony Stimulating Factor 1 (CSF-1 signaling, an innate immunity pathway not targeted by any other virus species. To evaluate effects of BARF1 in acute and persistent infection, we mutated the BARF1 homologue in the EBV-related herpesvirus, or lymphocryptovirus (LCV, naturally infecting rhesus macaques to create a recombinant rhLCV incapable of blocking CSF-1 (ΔrhBARF1. Rhesus macaques orally challenged with ΔrhBARF1 had decreased viral load indicating that CSF-1 is important for acute virus infection. Surprisingly, ΔrhBARF1 was also associated with dramatically lower virus setpoints during persistent infection. Normal acute viral load and normal viral setpoints during persistent rhLCV infection could be restored by Simian/Human Immunodeficiency Virus-induced immunosuppression prior to oral inoculation with ΔrhBARF1 or infection of immunocompetent animals with a recombinant rhLCV where the rhBARF1 was repaired. These results indicate that BARF1 blockade of CSF-1 signaling is an important immune evasion strategy for efficient acute EBV infection and a significant determinant for virus setpoint during persistent EBV infection.

Molecular design for recombinant adeno-associated virus (rAAV) vector production.

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Aponte-Ubillus, Juan Jose; Barajas, Daniel; Peltier, Joseph; Bardliving, Cameron; Shamlou, Parviz; Gold, Daniel

2018-02-01

Recombinant adeno-associated virus (rAAV) vectors are increasingly popular tools for gene therapy applications. Their non-pathogenic status, low inflammatory potential, availability of viral serotypes with different tissue tropisms, and prospective long-lasting gene expression are important attributes that make rAAVs safe and efficient therapeutic options. Over the last three decades, several groups have engineered recombinant AAV-producing platforms, yielding high titers of transducing vector particles. Current specific productivity yields from different platforms range from 10 3 to 10 5 vector genomes (vg) per cell, and there is an ongoing effort to improve vector yields in order to satisfy high product demands required for clinical trials and future commercialization.Crucial aspects of vector production include the molecular design of the rAAV-producing host cell line along with the design of AAV genes, promoters, and regulatory elements. Appropriately, configuring and balancing the expression of these elements not only contributes toward high productivity, it also improves process robustness and product quality. In this mini-review, the rational design of rAAV-producing expression systems is discussed, with special attention to molecular strategies that contribute to high-yielding, biomanufacturing-amenable rAAV production processes. Details on molecular optimization from four rAAV expression systems are covered: adenovirus, herpesvirus, and baculovirus complementation systems, as well as a recently explored yeast expression system.

Interactive Effects of Southern Rice Black-Streaked Dwarf Virus Infection of Host Plant and Vector on Performance of the Vector, Sogatella furcifera (Homoptera: Delphacidae).

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Lei, Wenbin; Liu, Danfeng; Li, Pei; Hou, Maolin

2014-10-01

Performance of insect vectors can be influenced by the viruses they transmit, either directly by infection of the vectors or indirectly via infection of the host plants. Southern rice black-streaked dwarf virus (SRBSDV) is a propagative virus transmitted by the white-backed planthopper, Sogatella furcifera (Hovath). To elucidate the influence of SRBSDV on the performance of white-backed planthopper, life parameters of viruliferous and nonviruliferous white-backed planthopper fed rice seedlings infected or noninfected with SRBSDV were measured using a factorial design. Regardless of the infection status of the rice plant host, viruliferous white-backed planthopper nymphs took longer to develop from nymph to adult than did nonviruliferous nymphs. Viruliferous white-backed planthopper females deposited fewer eggs than nonviruliferous females and both viruliferous and nonviruliferous white-backed planthopper females laid fewer eggs on infected than on noninfected plants. Longevity of white-backed planthopper females was also affected by the infection status of the rice plant and white-backed planthopper. Nonviruliferous white-backed planthopper females that fed on infected rice plants lived longer than the other three treatment groups. These results indicate that the performance of white-backed planthopper is affected by SRBSDV either directly (by infection of white-backed planthopper) or indirectly (by infection of rice plant). The extended development of viruliferous nymphs and the prolonged life span of nonviruliferous adults on infected plants may increase their likelihood of transmitting virus, which would increase virus spread. © 2014 Entomological Society of America.

Zika virus, vectors, reservoirs, amplifying hosts, and their potential to spread worldwide: what we know and what we should investigate urgently.

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Vorou, Rengina

2016-07-01

The widespread epidemic of Zika virus infection in South and Central America and the Caribbean in 2015, along with the increased incidence of microcephaly in fetuses born to mothers infected with Zika virus and the potential for worldwide spread, indicate the need to review the current literature regarding vectors, reservoirs, and amplification hosts. The virus has been isolated in Africa in mosquitoes of the genera Aedes, Anopheles, and Mansonia, and in Southeast Asia and the Pacific area in mosquitoes of the genus Aedes. Aedes albopictus has invaded several countries in Central Africa and all Mediterranean countries, and continues to spread throughout Central and Northern Europe. The wide distribution of the virus in animal hosts and vectors favors the emergence of recombinants. The virus has been isolated in monkeys, and antibodies have been detected in domestic sheep, goats, horses, cows, ducks, rodents, bats, orangutans, and carabaos. It is a public health imperative to define the domestic and wild animal reservoirs, amplification hosts, and vector capacity of the genera Aedes, Anopheles, and Mansonia. These variables will define the geographic distribution of Zika virus along with the indicated timing and scale of the environmental public health interventions worldwide. Copyright © 2016 The Author. Published by Elsevier Ltd.. All rights reserved.

Detection of foot-and-mouth disease virus RNA in pharyngeal epithelium biopsy samples obtained from infected cattle: Investigation of possible sites of virus replication and persistence

DEFF Research Database (Denmark)

Stenfeldt, Anna Carolina; Belsham, Graham

2012-01-01

measurements of the levels of FMDV RNA in the DSP as well as mandibular and retropharyngeal lymph nodes beyond 28 days after infection. Results indicated only low levels of FMDV RNA present in samples of pharyngeal epithelia during both early and persistent phases of infection with significantly higher levels...... of virus detected in pharyngeal excretions. It is concluded that the targeted area for sampling within the DSP does not harbour significant levels of virus replication during acute or persistent FMDV infection in cattle. Furthermore, the DSP and the mandibular and retropharyngeal lymph nodes cannot...

Breeding sites and species association of the main Bluetongue and Schmallenberg virus vectors, the Culicoides species (Diptera: Ceratopogonidae), in northern Europe

OpenAIRE

Zimmer, Jean-Yves; Losson, Bertrand; Saegerman, Claude; Haubruge, Eric; Francis, Frédéric

2013-01-01

Several species of Culicoides (Diptera: Ceratopogonidae) biting midges are biological vectors of bluetongue virus (BTV) and, as recently discovered, Schmallenberg virus (SBV) in northern Europe. Since their recent emergence in this part of the continent, these diseases that affect domestic and wild ruminants have caused considerable economic losses to the sheep and cattle industries. The substrates that are suitable for larval development of the main vector species are still relatively unknow...

Density threshold for Mopeia virus invasion and persistence in its host Mastomys natalensis

DEFF Research Database (Denmark)

Goyens, J.; Reijniers, J.; Borremans, B.

2013-01-01

. We developed a spatially explicit and individual-based SEIR model of Mopeia virus in multimammate mice Mastomys natalensis. This is an interesting model system for studying abundance thresholds because the host is the most common African rodent, populations fluctuate considerably and the virus...... is closely related to Lassa virus but non-pathogenic to humans so can be studied safely in the field. The simulations show that, while host density clearly is important, sharp thresholds are only to be expected for persistence (and not for invasion), since at short time-spans (as during invasion...

Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

Directory of Open Access Journals (Sweden)

Alec J Hirsch

2017-03-01

Full Text Available Zika virus (ZIKV, an emerging flavivirus, has recently spread explosively through the Western hemisphere. In addition to symptoms including fever, rash, arthralgia, and conjunctivitis, ZIKV infection of pregnant women can cause microcephaly and other developmental abnormalities in the fetus. We report herein the results of ZIKV infection of adult rhesus macaques. Following subcutaneous infection, animals developed transient plasma viremia and viruria from 1-7 days post infection (dpi that was accompanied by the development of a rash, fever and conjunctivitis. Animals produced a robust adaptive immune response to ZIKV, although systemic cytokine response was minimal. At 7 dpi, virus was detected in peripheral nervous tissue, multiple lymphoid tissues, joints, and the uterus of the necropsied animals. Notably, viral RNA persisted in neuronal, lymphoid and joint/muscle tissues and the male and female reproductive tissues through 28 to 35 dpi. The tropism and persistence of ZIKV in the peripheral nerves and reproductive tract may provide a mechanism of subsequent neuropathogenesis and sexual transmission.

Viral persistence, liver disease and host response in Hepatitis C-like virus rat model

DEFF Research Database (Denmark)

Trivedi, Sheetal; Murthy, Satyapramod; Sharma, Himanshu

2018-01-01

The lack of a relevant, tractable, and immunocompetent animal model for hepatitis C virus (HCV) has severely impeded investigations of viral persistence, immunity and pathogenesis. In the absence of immunocompetent models with robust HCV infection, homolog hepaciviruses in their natural host could...... potentially provide useful surrogate models. We isolated a rodent hepacivirus (RHV) from wild rats (Rattus norvegicus), RHV-rn1, acquired the complete viral genome sequence and developed an infectious reverse genetics system. RHV-rn1 resembles HCV in genomic features including the pattern of polyprotein...... cleavage sites and secondary structures in the viral 5' and 3' UTRs. We used site-directed and random mutagenesis to determine that only the first of the two miR-122 seed sites in viral 5'UTR is required for viral replication and persistence in rats. Next, we used the clone derived virus progeny to infect...

Transcriptomic response of the insect vector, Peregrinus maidis, to Maize mosaic rhabdovirus and identification of conserved responses to propagative viruses in hopper vectors.

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Martin, Kathleen M; Barandoc-Alviar, Karen; Schneweis, Derek J; Stewart, Catherine L; Rotenberg, Dorith; Whitfield, Anna E

2017-09-01

Maize mosaic virus (MMV) is a plant-pathogenic rhabdovirus that is transmitted by the corn planthopper, Peregrinus maidis, in a propagative manner. P. maidis supports long-term MMV infections with no negative effects on insect performance. To elucidate whole-body transcriptome responses to virus infection, RNA-Seq was used to examine differential gene expression of virus-infected adult insects, and libraries were prepared from replicated groups of virus-exposed insects and non-exposed insects. From the 68,003 de novo-assembled transcripts, 144 were differentially-expressed (DE) during viral infection with comparable numbers up- and down-regulated. DE transcripts with similarity to genes associated with transposable elements (i.e., RNA-directed DNA polymerases) were enriched and may represent a mechanisim for modulating virus infection. Comparison of the P. maidis DE transcripts to published propagative virus-responsive transcript databases for two other hopper vectors revealed that 16% of the DE transcripts were shared across the three systems and may represent conserved responses to propagative viruses. Copyright © 2017 Elsevier Inc. All rights reserved.

Ecological niche modelling of Rift Valley fever virus vectors in Baringo, Kenya

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Alfred O. Ochieng

2016-11-01

Full Text Available Background: Rift Valley fever (RVF is a vector-borne zoonotic disease that has an impact on human health and animal productivity. Here, we explore the use of vector presence modelling to predict the distribution of RVF vector species under climate change scenario to demonstrate the potential for geographic spread of Rift Valley fever virus (RVFV. Objectives: To evaluate the effect of climate change on RVF vector distribution in Baringo County, Kenya, with an aim of developing a risk map for spatial prediction of RVF outbreaks. Methodology: The study used data on vector presence and ecological niche modelling (MaxEnt algorithm to predict the effect of climatic change on habitat suitability and the spatial distribution of RVF vectors in Baringo County. Data on species occurrence were obtained from longitudinal sampling of adult mosquitoes and larvae in the study area. We used present (2000 and future (2050 Bioclim climate databases to model the vector distribution. Results: Model results predicted potential suitable areas with high success rates for Culex quinquefasciatus, Culex univitattus, Mansonia africana, and Mansonia uniformis. Under the present climatic conditions, the lowlands were found to be highly suitable for all the species. Future climatic conditions indicate an increase in the spatial distribution of Cx. quinquefasciatus and M. africana. Model performance was statistically significant. Conclusion: Soil types, precipitation in the driest quarter, precipitation seasonality, and isothermality showed the highest predictive potential for the four species.

Quantification of vector and host competence and abundance for Japanese Encephalitis Virus: a systematic review of the literature.

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Japanese encephalitis (JE) is a vector-borne disease caused by the Japanese encephalitis virus (JEV) that affects humans in Eastern and Southeastern Asia. Although it could be prevented by a vaccine, JE has no treatment and the inadvertent introduction of the virus into JEV-free countries, such as t...

Evolution of a Cell Culture-Derived Genotype 1a Hepatitis C Virus (H77S.2) during Persistent Infection with Chronic Hepatitis in a Chimpanzee

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Yi, MinKyung; Hu, Fengyu; Joyce, Michael; Saxena, Vikas; Welsch, Christoph; Chavez, Deborah; Guerra, Bernadette; Yamane, Daisuke; Veselenak, Ronald; Pyles, Rick; Walker, Christopher M.; Tyrrell, Lorne; Bourne, Nigel; Lanford, Robert E.

2014-01-01

ABSTRACT Persistent infection is a key feature of hepatitis C virus (HCV). However, chimpanzee infections with cell culture-derived viruses (JFH1 or related chimeric viruses that replicate efficiently in cell culture) have been limited to acute-transient infections with no pathogenicity. Here, we report persistent infection with chronic hepatitis in a chimpanzee challenged with cell culture-derived genotype 1a virus (H77S.2) containing 6 cell culture-adaptive mutations. Following acute-transient infection with a chimeric H77/JFH1 virus (HJ3-5), intravenous (i.v.) challenge with 106 FFU H77S.2 virus resulted in immediate seroconversion and, following an unusual 4- to 6-week delay, persistent viremia accompanied by alanine aminotransferase (ALT) elevation, intrahepatic innate immune responses, and diffuse hepatopathy. This first persistent infection with cell culture-produced HCV provided a unique opportunity to assess evolution of cell culture-adapted virus in vivo. Synonymous and nonsynonymous nucleotide substitution rates were greatest during the first 8 weeks of infection. Of 6 cell culture-adaptive mutations in H77S.2, Q1067R (NS3) had reverted to Q1067 and S2204I (NS5A) was replaced by T2204 within 8 weeks of infection. By 62 weeks, 4 of 6 mutations had reverted to the wild-type sequence, and all reverted to the wild-type sequence by 194 weeks. The data suggest H77S.2 virus has greater potential for persistence and pathogenicity than JFH1 and demonstrate both the capacity of a nonfit virus to persist for weeks in the liver in the absence of detectable viremia as well as strong selective pressure against cell culture-adaptive mutations in vivo. IMPORTANCE This study shows that mutations promoting the production of infectious genotype 1a HCV in cell culture have the opposite effect and attenuate replication in the liver of the only fully permissive animal species other than humans. It provides the only example to date of persistent infection in a chimpanzee

Evolution of a cell culture-derived genotype 1a hepatitis C virus (H77S.2) during persistent infection with chronic hepatitis in a chimpanzee.

Science.gov (United States)

Yi, MinKyung; Hu, Fengyu; Joyce, Michael; Saxena, Vikas; Welsch, Christoph; Chavez, Deborah; Guerra, Bernadette; Yamane, Daisuke; Veselenak, Ronald; Pyles, Rick; Walker, Christopher M; Tyrrell, Lorne; Bourne, Nigel; Lanford, Robert E; Lemon, Stanley M

2014-04-01

Persistent infection is a key feature of hepatitis C virus (HCV). However, chimpanzee infections with cell culture-derived viruses (JFH1 or related chimeric viruses that replicate efficiently in cell culture) have been limited to acute-transient infections with no pathogenicity. Here, we report persistent infection with chronic hepatitis in a chimpanzee challenged with cell culture-derived genotype 1a virus (H77S.2) containing 6 cell culture-adaptive mutations. Following acute-transient infection with a chimeric H77/JFH1 virus (HJ3-5), intravenous (i.v.) challenge with 10(6) FFU H77S.2 virus resulted in immediate seroconversion and, following an unusual 4- to 6-week delay, persistent viremia accompanied by alanine aminotransferase (ALT) elevation, intrahepatic innate immune responses, and diffuse hepatopathy. This first persistent infection with cell culture-produced HCV provided a unique opportunity to assess evolution of cell culture-adapted virus in vivo. Synonymous and nonsynonymous nucleotide substitution rates were greatest during the first 8 weeks of infection. Of 6 cell culture-adaptive mutations in H77S.2, Q1067R (NS3) had reverted to Q1067 and S2204I (NS5A) was replaced by T2204 within 8 weeks of infection. By 62 weeks, 4 of 6 mutations had reverted to the wild-type sequence, and all reverted to the wild-type sequence by 194 weeks. The data suggest H77S.2 virus has greater potential for persistence and pathogenicity than JFH1 and demonstrate both the capacity of a nonfit virus to persist for weeks in the liver in the absence of detectable viremia as well as strong selective pressure against cell culture-adaptive mutations in vivo. This study shows that mutations promoting the production of infectious genotype 1a HCV in cell culture have the opposite effect and attenuate replication in the liver of the only fully permissive animal species other than humans. It provides the only example to date of persistent infection in a chimpanzee challenged with cell

Bunyavirus-Vector Interactions

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Kate McElroy Horne

2014-11-01

Full Text Available The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family.

Persistence of Low Pathogenic Influenza A Virus in Water: A Systematic Review and Quantitative Meta-Analysis.

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Antonia E Dalziel

Full Text Available Avian influenza viruses are able to persist in the environment, in-between the transmission of the virus among its natural hosts. Quantifying the environmental factors that affect the persistence of avian influenza virus is important for influencing our ability to predict future outbreaks and target surveillance and control methods. We conducted a systematic review and quantitative meta-analysis of the environmental factors that affect the decay of low pathogenic avian influenza virus (LPAIV in water. Abiotic factors affecting the persistence of LPAIV have been investigated for nearly 40 years, yet published data was produced by only 26 quantitative studies. These studies have been conducted by a small number of principal authors (n = 17 and have investigated a narrow range of environmental conditions, all of which were based in laboratories with limited reflection of natural conditions. The use of quantitative meta-analytic techniques provided the opportunity to assess persistence across a greater range of conditions than each individual study can achieve, through the estimation of mean effect-sizes and relationships among multiple variables. Temperature was the most influential variable, for both the strength and magnitude of the effect-size. Moderator variables explained a large proportion of the heterogeneity among effect-sizes. Salinity and pH were important factors, although future work is required to broaden the range of abiotic factors examined, as well as including further diurnal variation and greater environmental realism generally. We were unable to extract a quantitative effect-size estimate for approximately half (50.4% of the reported experimental outcomes and we strongly recommend a minimum set of quantitative reporting to be included in all studies, which will allow robust assimilation and analysis of future findings. In addition we suggest possible means of increasing the applicability of future studies to the natural

Combined Therapy at Persistent Herpes Virus Infection in Sickly Children

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F. S. Kharlamova

2012-01-01

Full Text Available We examined 40 sickly children with recurrent croup (RC — 28 and bronchial obstruction (ROB — 8, (RC + ROB — 4 aged from 18 months till 14 years. We found that high frequency of persistent herpes viruses usually occurs as associations with CMV, EBV and human herpes virus 6 type. We substantiated anti viral and immune corrective therapy in two schemes compared in efficacy: the 1st group was administered monotherapy with Viferon, and the 2nd group received combined therapy Viferon + Arbidol in doses according to the age during three months. We received a more expressed clinical immunologic effect from the therapy with decreased antigenic load and frequency of recurrence of RC and ROB with Viferon application in suppositories in combination with Arbidol per orally in the intermittent scheme during three months. 

Membrane-bound SIV envelope trimers are immunogenic in ferrets after intranasal vaccination with a replication-competent canine distemper virus vector.

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Zhang, Xinsheng; Wallace, Olivia; Wright, Kevin J; Backer, Martin; Coleman, John W; Koehnke, Rebecca; Frenk, Esther; Domi, Arban; Chiuchiolo, Maria J; DeStefano, Joanne; Narpala, Sandeep; Powell, Rebecca; Morrow, Gavin; Boggiano, Cesar; Zamb, Timothy J; Richter King, C; Parks, Christopher L

2013-11-01

We are investigating canine distemper virus (CDV) as a vaccine vector for the delivery of HIV envelope (Env) that closely resembles the native trimeric spike. We selected CDV because it will promote vaccine delivery to lymphoid tissues, and because human exposure is infrequent, reducing potential effects of pre-existing immunity. Using SIV Env as a model, we tested a number of vector and gene insert designs. Vectors containing a gene inserted between the CDV H and L genes, which encoded Env lacking most of its cytoplasmic tail, propagated efficiently in Vero cells, expressed the immunogen on the cell surface, and incorporated the SIV glycoprotein into progeny virus particles. When ferrets were vaccinated intranasally, there were no signs of distress, vector replication was observed in the gut-associated lymphoid tissues, and the animals produced anti-SIV Env antibodies. These data show that live CDV-SIV Env vectors can safely induce anti-Env immune responses following intranasal vaccination. © 2013 Elsevier Inc. All rights reserved.

Implication of the Bacterial Endosymbiont Rickettsia spp. in Interactions of the Whitefly Bemisia tabaci with Tomato yellow leaf curl virus

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Kliot, Adi; Cilia, Michelle; Czosnek, Henryk

2014-01-01

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

West nile virus prevalence across landscapes is mediated by local effects of agriculture on vector and host communities.

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Crowder, David W; Dykstra, Elizabeth A; Brauner, Jo Marie; Duffy, Anne; Reed, Caitlin; Martin, Emily; Peterson, Wade; Carrière, Yves; Dutilleul, Pierre; Owen, Jeb P

2013-01-01

Arthropod-borne viruses (arboviruses) threaten the health of humans, livestock, and wildlife. West Nile virus (WNV), the world's most widespread arbovirus, invaded the United States in 1999 and rapidly spread across the county. Although the ecology of vectors and hosts are key determinants of WNV prevalence across landscapes, the factors shaping local vector and host populations remain unclear. Here, we used spatially-explicit models to evaluate how three land-use types (orchards, vegetable/forage crops, natural) and two climatic variables (temperature, precipitation) influence the prevalence of WNV infections and vector/host distributions at landscape and local spatial scales. Across landscapes, we show that orchard habitats were associated with greater prevalence of WNV infections in reservoirs (birds) and incidental hosts (horses), while increased precipitation was associated with fewer infections. At local scales, orchard habitats increased the prevalence of WNV infections in vectors (mosquitoes) and the abundance of mosquitoes and two key reservoir species, the American robin and the house sparrow. Thus, orchard habitats benefitted WNV vectors and reservoir hosts locally, creating focal points for the transmission of WNV at landscape scales in the presence of suitable climatic conditions.

Impact of Ultraviolet-Blocking Plastic Films on Insect Vectors of Virus Diseases Infesting Crisp Lettuce

OpenAIRE

Díaz Desani, Beatriz M.; Biurrun, R.; Moreno, Aránzazu; Nebreda, Miguel; Fereres, Alberto

2006-01-01

Ultraviolet (UV)-absorbing plastic films are being used as a photoselective barrier to control insect vectors and associated virus diseases in different horticultural crops. A 2-year experiment was carried out in northeastern Spain (Navarra) to evaluate the impact of a UV-blocking film (AD-IR AV) on the population density of insect pests and the spread of insect-transmitted virus diseases associated with head lettuce [Lactuca sativa (L.)]. Results showed that the UV-absorbing plastic film did...

Construction of a recombinant viral vector containing part of the nucleocapsid protein gene of newcastle disease virus

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Bader, D.E.

1995-09-01

This report describes the procedures used to clone a 673 base pair gene fragment of the major nucleocapsid protein gene of Newcastle disease virus into a viral vector molecule for the purpose of maintaining a stable, long-term, renewable source of this target sequence for gene probe studies. The gene fragment was prepared by reverse-transcription polymerase chain reaction of Newcastle disease virus RNA and was cloned into the viral DNA vector Ml3mp18 RF to produce a recombinant DNA molecule. The cloned fragment was shown to be present in the recombinant clones based on (i) clonal selection on indicator plates; (ii) restriction enzyme analysis; (iii) gene probe analysis and (iv) nested PCR amplification.

Zika Virus Persistently Infects and Is Basolaterally Released from Primary Human Brain Microvascular Endothelial Cells

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Megan C. Mladinich

2017-07-01

Full Text Available Zika virus (ZIKV is a mosquito-borne Flavivirus that has emerged as the cause of encephalitis and fetal microencephaly in the Americas. ZIKV uniquely persists in human bodily fluids for up to 6 months, is sexually transmitted, and traverses the placenta and the blood-brain barrier (BBB to damage neurons. Cells that support persistent ZIKV replication and mechanisms by which ZIKV establishes persistence remain enigmatic but central to ZIKV entry into protected neuronal compartments. The endothelial cell (EC lining of capillaries normally constrains transplacental transmission and forms the BBB, which selectively restricts access of blood constituents to neurons. We found that ZIKV (strain PRVABC59 persistently infects and continuously replicates in primary human brain microvascular ECs (hBMECs, without cytopathology, for >9 days and following hBMEC passage. ZIKV did not permeabilize hBMECs but was released basolaterally from polarized hBMECs, suggesting a direct mechanism for ZIKV to cross the BBB. ZIKV-infected hBMECs were rapidly resistant to alpha interferon (IFN-α and transiently induced, but failed to secrete, IFN-β and IFN-λ. Global transcriptome analysis determined that ZIKV constitutively induced IFN regulatory factor 7 (IRF7, IRF9, and IFN-stimulated genes (ISGs 1 to 9 days postinfection, despite persistently replicating in hBMECs. ZIKV constitutively induced ISG15, HERC5, and USP18, which are linked to hepatitis C virus (HCV persistence and IFN regulation, chemokine CCL5, which is associated with immunopathogenesis, as well as cell survival factors. Our results reveal that hBMECs act as a reservoir of persistent ZIKV replication, suggest routes for ZIKV to cross hBMECs into neuronal compartments, and define novel mechanisms of ZIKV persistence that can be targeted to restrict ZIKV spread.

Pseudacteon decapitating flies: Potential vectors of a fire ant virus?

International Nuclear Information System (INIS)

Valles, S.M.; Porter, S.D.

2007-01-01

Solenopsis invicta virus (SINV-1) is a positive-stranded RNA virus recently found to infect all stages of the red imported fire ant, Solenopsis invicta (Valles et al. 2004; Valles and Strong 2005). SINV-1 and a second genotype have been tentatively assigned to the Dicistroviridae (Mayo 2002). Infected individuals or colonies did not exhibit any immediate, discernible symptoms in the field. However, under stress from introduction into the laboratory, brood death was often observed among infected colonies, ultimately leading to the death of the entire colony (Valles et al. 2004). These characteristics are consistent with other insect-infecting positive-stranded RNA viruses. They often persist as inapparent, asymptomatic infections that, under certain conditions, induce replication within the host, resulting in observable symptoms and often death (Christian and Scotti 1998; Fernandez et al. 2002). The SINV infection rate among colonies was reported to be around 25% in Gainesville, Florida (Valles et al. 2004; Valles and Strong 2005). SINV vertical and horizontal transmission were inferred based on RT-PCR detection of virus genome in eggs and successful colony to colony transfer under lab conditions (Valles et al. 2004). However, the exact mechanisms by which the virus is spread from nest to nest in the field are unknown. Our results indicate that SINV does not replicate within Pseudacteon decapitating flies that parasitize S. invicta. Flies appeared to develop normally from SINV-infected S. invicta workers. Mechanical transmission of SINV to uninfected ants by oviposition appears unlikely

The fusion protein of wild-type canine distemper virus is a major determinant of persistent infection

International Nuclear Information System (INIS)

Plattet, Philippe; Rivals, Jean-Paul; Zuber, BenoIt; Brunner, Jean-Marc; Zurbriggen, Andreas; Wittek, Riccardo

2005-01-01

The wild-type A75/17 canine distemper virus (CDV) strain induces a persistent infection in the central nervous system but infects cell lines very inefficiently. In contrast, the genetically more distant Onderstepoort CDV vaccine strain (OP-CDV) induces extensive syncytia formation. Here, we investigated the roles of wild-type fusion (F WT ) and attachment (H WT ) proteins in Vero cells expressing, or not, the canine SLAM receptor by transfection experiments and by studying recombinants viruses expressing different combinations of wild-type and OP-CDV glycoproteins. We show that low fusogenicity is not due to a defect of the envelope proteins to reach the cell surface and that H WT determines persistent infection in a receptor-dependent manner, emphasizing the role of SLAM as a potent enhancer of fusogenicity. However, importantly, F WT reduced cell-to-cell fusion independently of the cell surface receptor, thus demonstrating that the fusion protein of the neurovirulent A75/17-CDV strain plays a key role in determining persistent infection

Robust production of virus-like particles and monoclonal antibodies with geminiviral replicon vectors in lettuce

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Lai, Huafang; He, Junyun; Engle, Michael; Diamond, Michael S.; Chen, Qiang

2011-01-01

Summary Pharmaceutical protein production in plants has been greatly promoted by the development of viral-based vectors and transient expression systems. Tobacco and related Nicotiana species are currently the most common host plants for generation of plant-made pharmaceutical proteins (PMPs). Downstream processing of target PMPs from these plants, however, is hindered by potential technical and regulatory difficulties due to the presence of high levels of phenolics and toxic alkaloids. Here, we explored the use of lettuce, which grows quickly yet produces low levels of secondary metabolites, and viral vector-based transient expression systems to develop a robust PMP production platform. Our results showed that a geminiviral replicon system based on the bean yellow dwarf virus permits high-level expression in lettuce of virus-like particles (VLP) derived from the Norwalk virus capsid protein and therapeutic monoclonal antibodies (mAbs) against Ebola and West Nile viruses. These vaccine and therapeutic candidates can be readily purified from lettuce leaves with scalable processing methods while fully retaining functional activity. Furthermore, this study also demonstrated the feasibility of using commercially produced lettuce for high-level PMP production. This allows our production system to have access to unlimited quantities of inexpensive plant material for large-scale production. These results establish a new production platform for biological pharmaceutical agents that is effective, safe, low-cost, and amenable to large-scale manufacturing. PMID:21883868

Enhancers Are Major Targets for Murine Leukemia Virus Vector Integration

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De Ravin, Suk See; Su, Ling; Theobald, Narda; Choi, Uimook; Macpherson, Janet L.; Poidinger, Michael; Symonds, Geoff; Pond, Susan M.; Ferris, Andrea L.; Hughes, Stephen H.

2014-01-01

ABSTRACT Retroviral vectors have been used in successful gene therapies. However, in some patients, insertional mutagenesis led to leukemia or myelodysplasia. Both the strong promoter/enhancer elements in the long terminal repeats (LTRs) of murine leukemia virus (MLV)-based vectors and the vector-specific integration site preferences played an important role in these adverse clinical events. MLV integration is known to prefer regions in or near transcription start sites (TSS). Recently, BET family proteins were shown to be the major cellular proteins responsible for targeting MLV integration. Although MLV integration sites are significantly enriched at TSS, only a small fraction of the MLV integration sites (integration map of more than one million integration sites from CD34+ hematopoietic stem cells transduced with a clinically relevant MLV-based vector. The integration sites form ∼60,000 tight clusters. These clusters comprise ∼1.9% of the genome. The vast majority (87%) of the integration sites are located within histone H3K4me1 islands, a hallmark of enhancers. The majority of these clusters also have H3K27ac histone modifications, which mark active enhancers. The enhancers of some oncogenes, including LMO2, are highly preferred targets for integration without in vivo selection. IMPORTANCE We show that active enhancer regions are the major targets for MLV integration; this means that MLV preferentially integrates in regions that are favorable for viral gene expression in a variety of cell types. The results provide insights for MLV integration target site selection and also explain the high risk of insertional mutagenesis that is associated with gene therapy trials using MLV vectors. PMID:24501411

The recombinant EHV-1 vector producing CDV hemagglutinin as potential vaccine against canine distemper.

Science.gov (United States)

Pan, Zihao; Liu, Jin; Ma, Jiale; Jin, Qiuli; Yao, Huochun; Osterrieder, Nikolaus

2017-10-01

Canine distemper virus (CDV), is a pantropic agent of morbillivirus that causes fetal disease in dogs. Base on a broad host rang of CDV, the continued vaccines inoculation is unavoidable to pose gene recombination risk in vaccine virus and wild virus. The current study presents the construction of novel vectors, using equine herpesvirus type 1 (EHV-1) expressing the canine distemper virus (CDV). The recent field strain hemagglutinin protein and nucleoprotein were used for the construction of the viral vector vaccines. Based on the Bacterial artificial chromosome (BAC) genomes of EHV-1 RacH strain, the recombinant EHV-1 vaccine virus encoding CDV hemagglutinin protein (EHV-H) or CDV nucleoprotein (EHV-N) was constructed separately. The constructed BACs were rescued after 72 h post infection, and the expression of H or N in the recombinant viruses was confirmed by western-blotting. Furthermore, high levels of neutralizing antibodies were induced persistently following vaccination in the groups EHV-H&EHV-N and EHV-H, but the EHV-N group. The groups of vaccinated EHV-H and EHV-H&EHV-N pups were monitored for clinical signs, whereas the vaccinated EHV-N group developed moderate symptoms. The present study demonstrated that EHV-1 based recombinant virus carrying CDV H could be a promising vaccine candidate against canine distemper. Copyright © 2017. Published by Elsevier Ltd.

A novel non-toxic combined CTA1-DD and ISCOMS adjuvant vector for effective mucosal immunization against influenza virus.

Science.gov (United States)

Eliasson, Dubravka Grdic; Helgeby, Anja; Schön, Karin; Nygren, Caroline; El-Bakkouri, Karim; Fiers, Walter; Saelens, Xavier; Lövgren, Karin Bengtsson; Nyström, Ida; Lycke, Nils Y

2011-05-23

Here we demonstrate that by using non-toxic fractions of saponin combined with CTA1-DD we can achieve a safe and above all highly efficacious mucosal adjuvant vector. We optimized the construction, tested the requirements for function and evaluated proof-of-concept in an influenza A virus challenge model. We demonstrated that the CTA1-3M2e-DD/ISCOMS vector provided 100% protection against mortality and greatly reduced morbidity in the mouse model. The immunogenicity of the vector was superior to other vaccine formulations using the ISCOM or CTA1-DD adjuvants alone. The versatility of the vector was best exemplified by the many options to insert, incorporate or admix vaccine antigens with the vector. Furthermore, the CTA1-3M2e-DD/ISCOMS could be kept 1 year at 4°C or as a freeze-dried powder without affecting immunogenicity or adjuvanticity of the vector. Strong serum IgG and mucosal IgA responses were elicited and CD4 T cell responses were greatly enhanced after intranasal administration of the combined vector. Together these findings hold promise for the combined vector as a mucosal vaccine against influenza virus infections including pandemic influenza. The CTA1-DD/ISCOMS technology represents a breakthrough in mucosal vaccine vector design which successfully combines immunomodulation and targeting in a safe and stable particulate formation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Tissue-specific expression of silkmoth chorion genes in vivo using Bombyx mori nuclear polyhedrosis virus as a transducing vector.

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Iatrou, K; Meidinger, R G

1990-01-01

A pair of silkmoth chorion chromosomal genes, HcA.12-HcB.12, was inserted into a baculovirus transfer vector, pBmp2, derived from the nuclear polyhedrosis virus of Bombyx mori. This vector, which permits the insertion of foreign genetic material in the vicinity of a mutationally inactivated polyhedrin gene, was used to acquire the corresponding recombinant virus. Injection of mutant silkmoth pupae that lack all Hc chorion genes with the recombinant virus resulted in the infection of all internal organs including follicular tissue. Analysis of RNA from infected tissues has demonstrated that the two chorion genes present in the viral genome are correctly transcribed under the control of their own promoter in follicular cells, the tissue in which chorion genes are normally expressed. The chorion primary transcripts are also correctly processed in the infected follicular cells and yield mature mRNAs indistinguishable from authentic chorion mRNAs present in wild-type follicles. These results demonstrate that recombinant nuclear polyhedrosis viruses can be used as transducing vectors for introducing genetic material of host origin into the cells of the organism and that the transduced genes are transiently expressed in a tissue-specific manner under the control of their resident regulatory sequences. Thus we show the in vivo expression of cloned genes under cellular promoter control in an insect other than Drosophila melanogaster. The approach should be applicable to all insect systems that are subject to nuclear polyhedrosis virus infection. Images PMID:2187186

Recombinant Newcastle disease virus-vectored vaccines against human and animal infectious diseases.

Science.gov (United States)

Duan, Zhiqiang; Xu, Houqiang; Ji, Xinqin; Zhao, Jiafu

2015-01-01

Recent advances in recombinant genetic engineering techniques have brought forward a leap in designing new vaccines in modern medicine. One attractive strategy is the application of reverse genetics technology to make recombinant Newcastle disease virus (rNDV) deliver protective antigens of pathogens. In recent years, numerous studies have demonstrated that rNDV-vectored vaccines can induce quicker and better humoral and mucosal immune responses than conventional vaccines and are protective against pathogen challenges. With deeper understanding of NDV molecular biology, it is feasible to develop gene-modified rNDV vaccines accompanied by good safety, high efficacy, low toxicity and better immunogenicity. This review summarizes the development of reverse genetics technology in using NDV as a promising vaccine vector to design new vaccines for human and animal use.

Foot-and-mouth disease virus persists in the light zone of germinal centres.

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Nicholas Juleff

Full Text Available Foot-and-mouth disease virus (FMDV is one of the most contagious viruses of animals and is recognised as the most important constraint to international trade in animals and animal products. Two fundamental problems remain to be understood before more effective control measures can be put in place. These problems are the FMDV "carrier state" and the short duration of immunity after vaccination which contrasts with prolonged immunity after natural infection. Here we show by laser capture microdissection in combination with quantitative real-time reverse transcription polymerase chain reaction, immunohistochemical analysis and corroborate by in situ hybridization that FMDV locates rapidly to, and is maintained in, the light zone of germinal centres following primary infection of naïve cattle. We propose that maintenance of non-replicating FMDV in these sites represents a source of persisting infectious virus and also contributes to the generation of long-lasting antibody responses against neutralising epitopes of the virus.

Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia.

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Sonja Hall-Mendelin

2016-09-01

Full Text Available Within the last 10 years Zika virus (ZIKV has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission.Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50 of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred.We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia.

Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia.

Science.gov (United States)

Hall-Mendelin, Sonja; Pyke, Alyssa T; Moore, Peter R; Mackay, Ian M; McMahon, Jamie L; Ritchie, Scott A; Taylor, Carmel T; Moore, Frederick A J; van den Hurk, Andrew F

2016-09-01

Within the last 10 years Zika virus (ZIKV) has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission. Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50) of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50)/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred. We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia.

Viral vectors for cystic fibrosis gene therapy: What does the future hold?

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Uta Griesenbach

2010-12-01

Full Text Available Uta Griesenbach1, Makoto Inoue2, Mamoru Hasegawa2, Eric WFW Alton11Department of Gene Therapy, Imperial College London, UK; The UK Cystic Fibrosis Gene Therapy Consortium; 2DNAVEC Corporation, Tsukuba, JapanAbstract: Gene transfer to the airway epithelium has been more difficult than originally anticipated, largely because of significant extra- and intracellular barriers in the lung. In general, viral vectors are more adapted to overcoming these barriers than nonviral gene transfer agents and are, therefore, more efficient in transferring genes into recipient cells. Viral vectors derived from adenovirus, adeno-associated virus, and Sendai virus, which all have a natural tropism for the airway epithelium, have been evaluated for cystic fibrosis (CF gene therapy. Although these vectors transduce airway epithelial cells efficiently, gene expression is transient and repeated administration is inefficient. They are, therefore, unlikely to be suitable for CF gene therapy. More recently, lentiviruses (LV have been assessed for lung gene transfer. In contrast to retroviruses, they transduce nondividing cells and randomly integrate into the genome. However, LVs do not have a natural tropism for the lung, and a significant amount of effort has been put into pseudotyping these vectors with proteins suitable for airway gene transfer. Several studies have shown that LV-mediated transduction leads to persistent gene expression (for the lifetime of the animal in the airways and, importantly, repeated administration is feasible. Thus, appropriately pseudotyped LV vectors are promising candidates for CF gene therapy. Here, we will review preclinical and clinical research related to viral CF gene therapy.Keywords: cystic fibrosis, gene therapy, adenovirus, AAV, lentivirus, Sendai virus

Characterization of rice black-streaked dwarf virus- and rice stripe virus-derived siRNAs in singly and doubly infected insect vector Laodelphax striatellus.

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Junmin Li

Full Text Available Replication of RNA viruses in insect cells triggers an antiviral defense that is mediated by RNA interference (RNAi which generates viral-derived small interfering RNAs (siRNAs. However, it is not known whether an antiviral RNAi response is also induced in insects by reoviruses, whose double-stranded RNA genome replication is thought to occur within core particles. Deep sequencing of small RNAs showed that when the small brown planthopper (Laodelphax striatellus was infected by Rice black-streaked dwarf virus (RBSDV (Reoviridae; Fijivirus, more viral-derived siRNAs accumulated than when the vector insect was infected by Rice stripe virus (RSV, a negative single-stranded RNA virus. RBSDV siRNAs were predominantly 21 and 22 nucleotides long and there were almost equal numbers of positive and negative sense. RBSDV siRNAs were frequently generated from hotspots in the 5'- and 3'-terminal regions of viral genome segments but these hotspots were not associated with any predicted RNA secondary structures. Under laboratory condition, L. striatellus can be infected simultaneously with RBSDV and RSV. Double infection enhanced the accumulation of particular genome segments but not viral coat protein of RBSDV and correlated with an increase in the abundance of siRNAs derived from RBSDV. The results of this study suggest that reovirus replication in its insect vector potentially induces an RNAi-mediated antiviral response.

Next generation of adeno-associated virus 2 vectors: Point mutations in tyrosines lead to high-efficiency transduction at lower doses

OpenAIRE

Zhong, Li; Li, Baozheng; Mah, Cathryn S.; Govindasamy, Lakshmanan; Agbandje-McKenna, Mavis; Cooper, Mario; Herzog, Roland W.; Zolotukhin, Irene; Warrington, Kenneth H.; Weigel-Van Aken, Kirsten A.; Hobbs, Jacqueline A.; Zolotukhin, Sergei; Muzyczka, Nicholas; Srivastava, Arun

2008-01-01

Recombinant adeno-associated virus 2 (AAV2) vectors are in use in several Phase I/II clinical trials, but relatively large vector doses are needed to achieve therapeutic benefits. Large vector doses also trigger an immune response as a significant fraction of the vectors fails to traffic efficiently to the nucleus and is targeted for degradation by the host cell proteasome machinery. We have reported that epidermal growth factor receptor protein tyrosine kinase (EGFR-PTK) signaling negatively...

Data fusion and machine learning to identify threat vectors for the Zika virus and classify vulnerability

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Gentle, J. N., Jr.; Kahn, A.; Pierce, S. A.; Wang, S.; Wade, C.; Moran, S.

2016-12-01

With the continued spread of the zika virus in the United States in both Florida and Virginia, increased public awareness, prevention and targeted prediction is necessary to effectively mitigate further infection and propagation of the virus throughout the human population. The goal of this project is to utilize publicly accessible data and HPC resources coupled with machine learning algorithms to identify potential threat vectors for the spread of the zika virus in Texas, the United States and globally by correlating available zika case data collected from incident reports in medical databases (e.g., CDC, Florida Department of Health) with known bodies of water in various earth science databases (e.g., USGS NAQWA Data, NASA ASTER Data, TWDB Data) and by using known mosquito population centers as a proxy for trends in population distribution (e.g., WHO, European CDC, Texas Data) while correlating historical trends in the spread of other mosquito borne diseases (e.g., chikungunya, malaria, dengue, yellow fever, west nile, etc.). The resulting analysis should refine the identification of the specific threat vectors for the spread of the virus which will correspondingly increase the effectiveness of the limited resources allocated towards combating the disease through better strategic implementation of defense measures. The minimal outcome of this research is a better understanding of the factors involved in the spread of the zika virus, with the greater potential to save additional lives through more effective resource utilization and public outreach.

Inter-Seasonal Influenza is Characterized by Extended Virus Transmission and Persistence

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Patterson Ross, Zoe; Komadina, Naomi; Deng, Yi-Mo; Spirason, Natalie; Kelly, Heath A.; Sullivan, Sheena G.; Barr, Ian G.; Holmes, Edward C.

2015-01-01

The factors that determine the characteristic seasonality of influenza remain enigmatic. Current models predict that occurrences of influenza outside the normal surveillance season within a temperate region largely reflect the importation of viruses from the alternate hemisphere or from equatorial regions in Asia. To help reveal the drivers of seasonality we investigated the origins and evolution of influenza viruses sampled during inter-seasonal periods in Australia. To this end we conducted an expansive phylogenetic analysis of 9912, 3804, and 3941 hemagglutinnin (HA) sequences from influenza A/H1N1pdm, A/H3N2, and B, respectively, collected globally during the period 2009-2014. Of the 1475 viruses sampled from Australia, 396 (26.8% of Australian, or 2.2% of global set) were sampled outside the monitored temperate influenza surveillance season (1 May – 31 October). Notably, rather than simply reflecting short-lived importations of virus from global localities with higher influenza prevalence, we documented a variety of more complex inter-seasonal transmission patterns including “stragglers” from the preceding season and “heralds” of the forthcoming season, and which included viruses sampled from clearly temperate regions within Australia. We also provide evidence for the persistence of influenza B virus between epidemic seasons, in which transmission of a viral lineage begins in one season and continues throughout the inter-seasonal period into the following season. Strikingly, a disproportionately high number of inter-seasonal influenza transmission events occurred in tropical and subtropical regions of Australia, providing further evidence that climate plays an important role in shaping patterns of influenza seasonality. PMID:26107631

Safety mechanism assisted by the repressor of tetracycline (SMART) vaccinia virus vectors for vaccines and therapeutics.

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Grigg, Patricia; Titong, Allison; Jones, Leslie A; Yilma, Tilahun D; Verardi, Paulo H

2013-09-17

Replication-competent viruses, such as Vaccinia virus (VACV), are powerful tools for the development of oncolytic viral therapies and elicit superior immune responses when used as vaccine and immunotherapeutic vectors. However, severe complications from uncontrolled viral replication can occur, particularly in immunocompromised individuals or in those with other predisposing conditions. VACVs constitutively expressing interferon-γ (IFN-γ) replicate in cell culture indistinguishably from control viruses; however, they replicate in vivo to low or undetectable levels, and are rapidly cleared even in immunodeficient animals. In an effort to develop safe and highly effective replication-competent VACV vectors, we established a system to inducibly express IFN-γ. Our SMART (safety mechanism assisted by the repressor of tetracycline) vectors are designed to express the tetracycline repressor under a constitutive VACV promoter and IFN-γ under engineered tetracycline-inducible promoters. Immunodeficient SCID mice inoculated with VACVs not expressing IFN-γ demonstrated severe weight loss, whereas those given VACVs expressing IFN-γ under constitutive VACV promoters showed no signs of infection. Most importantly, mice inoculated with a VACV expressing the IFN-γ gene under an inducible promoter remained healthy in the presence of doxycycline, but exhibited severe weight loss in the absence of doxycycline. In this study, we developed a safety mechanism for VACV based on the conditional expression of IFN-γ under a tightly controlled tetracycline-inducible VACV promoter for use in vaccines and oncolytic cancer therapies.

Transcriptomic profiling of diverse Aedes aegypti strains reveals increased basal-level immune activation in dengue virus-refractory populations and identifies novel virus-vector molecular interactions.

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Shuzhen Sim

Full Text Available Genetic variation among Aedes aegypti populations can greatly influence their vector competence for human pathogens such as the dengue virus (DENV. While intra-species transcriptome differences remain relatively unstudied when compared to coding sequence polymorphisms, they also affect numerous aspects of mosquito biology. Comparative molecular profiling of mosquito strain transcriptomes can therefore provide valuable insight into the regulation of vector competence. We established a panel of A. aegypti strains with varying levels of susceptibility to DENV, comprising both laboratory-maintained strains and field-derived colonies collected from geographically distinct dengue-endemic regions spanning South America, the Caribbean, and Southeast Asia. A comparative genome-wide gene expression microarray-based analysis revealed higher basal levels of numerous immunity-related gene transcripts in DENV-refractory mosquito strains than in susceptible strains, and RNA interference assays further showed different degrees of immune pathway contribution to refractoriness in different strains. By correlating transcript abundance patterns with DENV susceptibility across our panel, we also identified new candidate modulators of DENV infection in the mosquito, and we provide functional evidence for two potential DENV host factors and one potential restriction factor. Our comparative transcriptome dataset thus not only provides valuable information about immune gene regulation and usage in natural refractoriness of mosquito populations to dengue virus but also allows us to identify new molecular interactions between the virus and its mosquito vector.

Minor Coat and Heat Shock Proteins Are Involved in the Binding of Citrus Tristeza Virus to the Foregut of Its Aphid Vector, Toxoptera citricida.

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Killiny, N; Harper, S J; Alfaress, S; El Mohtar, C; Dawson, W O

2016-11-01

Vector transmission is a critical stage in the viral life cycle, yet for most plant viruses how they interact with their vector is unknown or is explained by analogy with previously described relatives. Here we examined the mechanism underlying the transmission of citrus tristeza virus (CTV) by its aphid vector, Toxoptera citricida, with the objective of identifying what virus-encoded proteins it uses to interact with the vector. Using fluorescently labeled virions, we demonstrated that CTV binds specifically to the lining of the cibarium of the aphid. Through in vitro competitive binding assays between fluorescent virions and free viral proteins, we determined that the minor coat protein is involved in vector interaction. We also found that the presence of two heat shock-like proteins, p61 and p65, reduces virion binding in vitro Additionally, treating the dissected mouthparts with proteases did not affect the binding of CTV virions. In contrast, chitinase treatment reduced CTV binding to the foregut. Finally, competition with glucose, N-acetyl-β-d-glucosamine, chitobiose, and chitotriose reduced the binding. These findings together suggest that CTV binds to the sugar moieties of the cuticular surface of the aphid cibarium, and the binding involves the concerted activity of three virus-encoded proteins. Limited information is known about the specific interactions between citrus tristeza virus and its aphid vectors. These interactions are important for the process of successful transmission. In this study, we localized the CTV retention site as the cibarium of the aphid foregut. Moreover, we demonstrated that the nature of these interactions is protein-carbohydrate binding. The viral proteins, including the minor coat protein and two heat shock proteins, bind to sugar moieties on the surface of the foregut. These findings will help in understanding the transmission mechanism of CTV by the aphid vector and may help in developing control strategies which interfere

Migration of rice planthoppers and their vectored re-emerging and novel rice viruses in East Asia

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Akira eOtuka

2013-10-01

Full Text Available This review examines recent studies of the migration of three rice planthoppers, Laodelphax striatellus, Sogatella furcifera, and Nilaparvata lugens, in East Asia. Laodelphax striatellus has recently broken out in Jiangsu province, eastern China. The population density in the province started to increase in the early 2000s and peaked in 2004. In 2005, Rice stripe virus (RSV viruliferous rate of L. striatellus peaked at 31.3%. Since then, rice stripe disease spread severely across the whole province. Due to the migration of the RSV vectors, the rice stripe disease spread to neighboring countries Japan and Korea. An overseas migration of L. striatellus that occurred in 2008 was analyzed, when a slow-moving cold vortex, a type of low pressure system, reached western Japan from Jiangsu, carrying the insects into Japan. Subsequently the rice stripe diseases struck these areas in Japan severely. In Korea, similar situations occurred in 2009, 2011, and 2012. Their migration sources were also estimated to be in Jiangsu by backward trajectory analysis. Rice black-streaked dwarf virus, whose vector is L. striatellus, has recently re-emerged in eastern China, and the evidence for overseas migrations of the virus, just like the RSV’s migrations, has been given. A method of predicting the overseas migration of L. striatellus has been developed by Japanese, Chinese, and Korean institutes. An evaluation of the prediction showed that this method properly predicted migration events that occurred in East Asia from 2008 to 2011. Southern rice black-streaked dwarf virus (SRBSDV was first found in Guangdong province. Its vector is S. furcifera. An outbreak of SRBSDV occurred in southern China in 2009 and spread to Vietnam the same year. This disease and virus were also found in Japan in 2010. The epidemic triggered many migration studies to investigate concrete spring-summer migration routes in China, and the addition of migration sources for early arrivals in

Migration of rice planthoppers and their vectored re-emerging and novel rice viruses in East Asia.

Science.gov (United States)

Otuka, Akira

2013-10-28

This review examines recent studies of the migration of three rice planthoppers, Laodelphax striatellus, Sogatella furcifera, and Nilaparvata lugens, in East Asia. Laodelphax striatellus has recently broken out in Jiangsu province, eastern China. The population density in the province started to increase in the early 2000s and peaked in 2004. In 2005, Rice stripe virus (RSV) viruliferous rate of L. striatellus peaked at 31.3%. Since then, rice stripe disease spread severely across the whole province. Due to the migration of the RSV vectors, the rice stripe disease spread to neighboring countries Japan and Korea. An overseas migration of L. striatellus that occurred in 2008 was analyzed, when a slow-moving cold vortex, a type of low pressure system, reached western Japan from Jiangsu, carrying the insects into Japan. Subsequently the rice stripe diseases struck these areas in Japan severely. In Korea, similar situations occurred in 2009, 2011, and 2012. Their migration sources were also estimated to be in Jiangsu by backward trajectory analysis. Rice black-streaked dwarf virus, whose vector is L. striatellus, has recently re-emerged in eastern China, and the evidence for overseas migrations of the virus, just like the RSV's migrations, has been given. A method of predicting the overseas migration of L. striatellus has been developed by Japanese, Chinese, and Korean institutes. An evaluation of the prediction showed that this method properly predicted migration events that occurred in East Asia from 2008 to 2011. Southern rice black-streaked dwarf virus (SRBSDV) was first found in Guangdong province. Its vector is S. furcifera. An outbreak of SRBSDV occurred in southern China in 2009 and spread to Vietnam the same year. This disease and virus were also found in Japan in 2010. The epidemic triggered many migration studies to investigate concrete spring-summer migration routes in China, and the addition of migration sources for early arrivals in Guangdong and Guangxi

Biological and immunogenic properties of rabies virus glycoprotein expressed by canine herpesvirus vector.

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Xuan, X; Tuchiya, K; Sato, I; Nishikawa, Y; Onoderaz, Y; Takashima, Y; Yamamoto, A; Katsumata, A; Iwata, A; Ueda, S; Mikami, T; Otsuka, H

1998-01-01

In order to evaluate whether canine herpesvirus (CHV) could be used as a live vector for the expression of heterologous immunogenes, we constructed a recombinant canine herpesvirus (CHV) expressing glycoprotein (G protein) of rabies virus (RV). The gene of G protein was inserted within the thymidine kinase gene of CHV YP11mu strain under the control of the human cytomegalovirus immediate early promoter. The G protein expressed by the recombinant CHV was processed and transported to the cell surface as in RV infected cells, and showed the same biological activities such as low pH dependent cell fusion and hemadsorption. The antigenic authenticity of the recombinant G protein was confirmed by a panel of monoclonal antibodies specific for G protein. Dogs inoculated intransally with the recombinant CHV produced higher titres of virus neutralizing antibodies against RV than those inoculated with a commercial, inactivated rabies vaccine. These results suggest that the CHV recombinant expressing G protein can be used as a vaccine to control canine rabies and that CHV may be useful as a vector to develop live recombinant against other infectious diseases in dogs.

Mal de Río Cuarto Virus Infection Triggers the Production of Distinctive Viral-Derived siRNA Profiles in Wheat and Its Planthopper Vector.

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de Haro, Luis A; Dumón, Analía D; Mattio, María F; Argüello Caro, Evangelina Beatriz; Llauger, Gabriela; Zavallo, Diego; Blanc, Hervé; Mongelli, Vanesa C; Truol, Graciela; Saleh, María-Carla; Asurmendi, Sebastián; Del Vas, Mariana

2017-01-01

Plant reoviruses are able to multiply in gramineae plants and delphacid vectors encountering different defense strategies with unique features. This study aims to comparatively assess alterations of small RNA (sRNA) populations in both hosts upon virus infection. For this purpose, we characterized the sRNA profiles of wheat and planthopper vectors infected by Mal de Río Cuarto virus (MRCV, Fijivirus, Reoviridae ) and quantified virus genome segments by quantitative reverse transcription PCR We provide evidence that plant and insect silencing machineries differentially recognize the viral genome, thus giving rise to distinct profiles of virus-derived small interfering RNAs (vsiRNAs). In plants, most of the virus genome segments were targeted preferentially within their upstream sequences and vsiRNAs mapped with higher density to the smaller genome segments than to the medium or larger ones. This tendency, however, was not observed in insects. In both hosts, vsiRNAs were equally derived from sense and antisense RNA strands and the differences in vsiRNAs accumulation did not correlate with mRNAs accumulation. We also established that the piwi-interacting RNA (piRNA) pathway was active in the delphacid vector but, contrary to what is observed in virus-infected mosquitoes, virus-specific piRNAs were not detected. This work contributes to the understanding of the silencing response in insect and plant hosts.

A new model of Hantaan virus persistence in mice: the balance between HTNV infection and CD8+ T-cell responses

International Nuclear Information System (INIS)

Araki, Koichi; Yoshimatsu, Kumiko; Lee, Byoung-Hee; Kariwa, Hiroaki; Takashima, Ikuo; Arikawa, Jiro

2004-01-01

We established a viral persistence model that involves the adoptive transfer of spleen cells from immunocompetent mice (H-2 d ) into Hantaan virus (HTNV)-infected severe combined immunodeficient (SCID, H-2 d ) mice. The infection is maintained despite the presence of neutralizing antibodies, without apparent signs of disease, and there is a correlation between HTNV persistence and the lack of HTNV-specific CD8 + T cells. In addition, disseminated HTNV infection before the initiation of immune responses appears to be important for virus persistence. The suppression of HTNV-specific CD8 + T cells in the present model appears to occur at the periphery. The present study also demonstrates that CD8 + T cells contribute to the clearance of HTNV. Thus, it seems that HTNV-specific CD8 + T cells play a key role in HTNV persistence in mice. This model of viral persistence is useful for studies of immune responses and immunocytotherapy against viral infection

Persistence and clearance of Ebola virus RNA from seminal fluid of Ebola virus disease survivors: a longitudinal analysis and modelling study

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Daouda Sissoko, MD

2017-01-01

Full Text Available Summary: Background: By January, 2016, all known transmission chains of the Ebola virus disease (EVD outbreak in west Africa had been stopped. However, there is concern about persistence of Ebola virus in the reproductive tract of men who have survived EVD. We aimed to use biostatistical modelling to describe the dynamics of Ebola virus RNA load in seminal fluid, including clearance parameters. Methods: In this longitudinal study, we recruited men who had been discharged from three Ebola treatment units in Guinea between January and July, 2015. Participants provided samples of seminal fluid at follow-up every 3–6 weeks, which we tested for Ebola virus RNA using quantitative real-time RT-PCR. Representative specimens from eight participants were then inoculated into immunodeficient mice to test for infectivity. We used a linear mixed-effect model to analyse the dynamics of virus persistence in seminal fluid over time. Findings: We enrolled 26 participants and tested 130 seminal fluid specimens; median follow up was 197 days (IQR 187–209 days after enrolment, which corresponded to 255 days (228–287 after disease onset. Ebola virus RNA was detected in 86 semen specimens from 19 (73% participants. Median duration of Ebola virus RNA detection was 158 days after onset (73–181; maximum 407 days at end of follow-up. Mathematical modelling of the quantitative time-series data showed a mean clearance rate of Ebola virus RNA from seminal fluid of −0·58 log units per month, although the clearance kinetic varied greatly between participants. Using our biostatistical model, we predict that 50% and 90% of male survivors clear Ebola virus RNA from seminal fluid at 115 days (90% prediction interval 72–160 and 294 days (212–399 after disease onset, respectively. We also predicted that the number of men positive for Ebola virus RNA in affected countries would decrease from about 50 in January 2016, to fewer than 1 person by July, 2016. Infectious

Current status of the Citrus leprosis virus (CiLV -C and its vector Brevipalpus phoenicis (Geijskes

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Guillermo León M

2012-08-01

Full Text Available The Citrus leprosis virus CiLV-C is a quarantine disease of economic importance. Over the past 15 years, this disease has spread to several countries of Central and South America. Colombia has about 45,000 hectares of citrus planted with an annual production of 750,000 tonnes. The CiLV-C has only been detected in the departments of Meta, Casanare and recently Tolima. Meta has 4,300 hectares representing 10% of the national cultivated area, and Casanare, where CiLV-C appeared in 2004, has no more than 500 ha planted with citrus. The presence of the Citrus leprosis virus in Colombia could affect the international market for citrus, other crops and ornamental plants with the United States and other countries without the disease. The false spider mite Brevipalpus phoenicis (Geijskes (Acari: Tenuipalpidae is the main vector of the CiLV-C. Disease management is based on control programs of the vector and diminishing host plants. Chemical mite control is expensive, wasteful and generates resistance to different acaricides. This paper provides basic information on CiLV-C and its vector, advances in diagnosis and methods to control the disease and prevention of its spread

Ovicidal and larvicidal effects of garlic and asafoetida essential oils against West Nile virus vectors

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We examined the chemical composition of garlic and asafoetida essential oils and their individual and combined toxicity against larvae of two West Nile virus vectors, Culex pipiens pipiens and Cx. restuans. The effect of the two essential oils on egg hatch was also examined. Ten and twelve compounds...

Previously infected chimpanzees are not consistently protected against reinfection or persistent infection after reexposure to the identical hepatitis C virus strain

DEFF Research Database (Denmark)

Bukh, Jens; Thimme, Robert; Meunier, Jean-Christophe

2008-01-01

Protective immunity after resolved hepatitis C virus (HCV) infection has been reported. However, the breadth of this immunity has remained controversial, and the role of neutralizing antibodies has not been well-defined. In the present study, two chimpanzees (CH96A008 and CH1494) with resolved...... homologous rechallenges with monoclonal H77C or polyclonal H77 and after six heterologous rechallenges with HC-J4 (genotype 1b) or HC-J6 (genotype 2a) viruses. Subsequently, a final challenge with H77C resulted in persistent HCV infection. In both chimpanzees, serum neutralizing antibodies against retroviral...... of viruses recovered from CH1494 after the two homologous rechallenges that resulted in transient viremia were identical with the H77C virus. In contrast, the polyprotein sequences of viruses recovered from both chimpanzees after homologous rechallenge resulting in persistent infection had numerous changes...

Properties of a herpes simplex virus multiple immediate-early gene-deleted recombinant as a vaccine vector

International Nuclear Information System (INIS)

Watanabe, Daisuke; Brockman, Mark A.; Ndung'u, Thumbi; Mathews, Lydia; Lucas, William T.; Murphy, Cynthia G.; Felber, Barbara K.; Pavlakis, George N.; Deluca, Neal A.; Knipe, David M.

2007-01-01

Herpes simplex virus (HSV) recombinants induce durable immune responses in rhesus macaques and mice and have induced partial protection in rhesus macaques against mucosal challenge with virulent simian immunodeficiency virus (SIV). In this study, we evaluated the properties of a new generation HSV vaccine vector, an HSV-1 multiple immediate-early (IE) gene deletion mutant virus, d106, which contains deletions in the ICP4, ICP27, ICP22, and ICP47 genes. Because several of the HSV IE genes have been implicated in immune evasion, inactivation of the genes encoding these proteins was expected to result in enhanced immunogenicity. The d106 virus expresses few HSV gene products and shows minimal cytopathic effect in cultured cells. When d106 was inoculated into mice, viral DNA accumulated at high levels in draining lymph nodes, consistent with an ability to transduce dendritic cells and activate their maturation and movement to lymph nodes. A d106 recombinant expressing Escherichia coli β-galactosidase induced durable β-gal-specific IgG and CD8 + T cell responses in naive and HSV-immune mice. Finally, d106-based recombinants have been constructed that express simian immunodeficiency virus (SIV) gag, env, or a rev-tat-nef fusion protein for several days in cultured cells. Thus, d106 shows many of the properties desirable in a vaccine vector: limited expression of HSV gene products and cytopathogenicity, high level expression of transgenes, ability to induce durable immune responses, and an ability to transduce dendritic cells and induce their maturation and migration to lymph nodes

A built-in co-carcinogenic effect due to viruses involved in latent or persistent infections

DEFF Research Database (Denmark)

Hersoug, Lars-Georg; Arnau, José

2007-01-01

instability. Because of chromosomal instability, the genome of these cell lines will lead to changes from generation to generation and will face a remarkable selection pressure both from lost traits, apoptosis, and from the immune system. Viruses causing latent or persistent infections have evolved many...

Gene therapy with adeno-associated virus vector 5-human factor IX in adults with hemophilia B

DEFF Research Database (Denmark)

Miesbach, Wolfgang; Meijer, Karina; Coppens, Michiel

2018-01-01

Hemophilia B gene therapy aims to ameliorate bleeding risk and provide endogenous factor IX (FIX) activity/synthesis through a single treatment, eliminating the requirement for FIX concentrate. AMT-060 combines an adeno-associated virus-5 (AAV5) vector with a liver-specific promoter driving expre...

Transient expression of the influenza A virus PB1-F2 protein using a plum pox virus-based vector in Nicotiana benthamiana.

Science.gov (United States)

Kamencayová, M; Košík, I; Hunková, J; Subr, Z W

2014-01-01

PB1-F2 protein of influenza A virus (IAV) was cloned in a plum pox virus (PPV) genome-based vector and attempts to express it in biolistically transfected Nicotiana benthamiana plants were performed. The vector-insert construct replicated in infected plants properly and was stable during repeated passage by mechanical inoculation, as demonstrated by disease symptoms and immunoblot detection of PPV capsid protein, while PB1-F2-specific band was more faint. We showed that it was due its low solubility. Modification of sample preparation (denaturation/solubilization preceding the centrifugation of cell debris) led to substantial signal enhancement. Maximal level of PB1-F2 expression in plants was observed 12 days post inoculation (dpi). Only 1% SDS properly solubilized the protein, other detergents were much less efficient. Solubilization with 8M urea released approximately 50% of PB1-F2 from the plant tissues, thus the treatment with this removable chaotropic agent may be a good starting point for the purification of the protein for eventual functional studies in the future.

Comparison of ‘HoBi’-like viral populations among persistent infected calves generated under experimental conditions and to inoculum virus

Science.gov (United States)

Like other members from the Pestivirus genus, ‘HoBi’-like pestiviruses cause economic losses for cattle producers due to both acute and persistent infections. Pestivirus exist as quasispecies (swarms of individual viruses) in persistently infected (PI) animals leading to viral populations that are m...

[Characteristics of long-term persisting strains of tick-borne encephalitis virus in different forms of the chronic process in animals].

Science.gov (United States)

Frolova, T V; Pogodina, V V; Frolova, M P; Karmysheva, V Ia

1982-01-01

The properties of the Vasilchenko strain of tick-borne encephalitis (TBE) virus and its 3 variants isolated at various stages of persistent infection (383, 453, and 535 days) in Macaca rhesus monkeys and Syrian hamsters with different forms of the chronic TBE were studied. The process characterized by chronic focal inflammatory-degenerative changes in the brains of hamsters without the disturbance of motor functions was associated with persistence of different kinds of virus-specific antigens without virulent virus production. Brain explants of this group of hamsters yielded a virus with cytopathogenic properties but not pathogenic for mice. In a chronic disease developing without the initial acute period, a virus was recovered from hamsters which proved to be virulent for mice and to possess the hemagglutinating and high invasive activity. The most virulent strain was isolated from monkeys with continuously progressive chronic encephalitis with steady paralysis of the extremities. This isolate differed from the parental Vasilchenko strain by a high pathogenicity for hamsters by intracerebral and subcutaneous routes, and thermostability at 50 degrees C.

Persistence and clearance of Ebola virus RNA from seminal fluid of Ebola virus disease survivors: a longitudinal analysis and modelling study.

Science.gov (United States)

Sissoko, Daouda; Duraffour, Sophie; Kerber, Romy; Kolie, Jacques Seraphin; Beavogui, Abdoul Habib; Camara, Alseny-Modet; Colin, Géraldine; Rieger, Toni; Oestereich, Lisa; Pályi, Bernadett; Wurr, Stephanie; Guedj, Jeremie; Nguyen, Thi Huyen Tram; Eggo, Rosalind M; Watson, Conall H; Edmunds, W John; Bore, Joseph Akoi; Koundouno, Fara Raymond; Cabeza-Cabrerizo, Mar; Carter, Lisa L; Kafetzopoulou, Liana Eleni; Kuisma, Eeva; Michel, Janine; Patrono, Livia Victoria; Rickett, Natasha Y; Singethan, Katrin; Rudolf, Martin; Lander, Angelika; Pallasch, Elisa; Bockholt, Sabrina; Rodríguez, Estefanía; Di Caro, Antonino; Wölfel, Roman; Gabriel, Martin; Gurry, Céline; Formenty, Pierre; Keïta, Sakoba; Malvy, Denis; Carroll, Miles W; Anglaret, Xavier; Günther, Stephan

2017-01-01

By January, 2016, all known transmission chains of the Ebola virus disease (EVD) outbreak in west Africa had been stopped. However, there is concern about persistence of Ebola virus in the reproductive tract of men who have survived EVD. We aimed to use biostatistical modelling to describe the dynamics of Ebola virus RNA load in seminal fluid, including clearance parameters. In this longitudinal study, we recruited men who had been discharged from three Ebola treatment units in Guinea between January and July, 2015. Participants provided samples of seminal fluid at follow-up every 3-6 weeks, which we tested for Ebola virus RNA using quantitative real-time RT-PCR. Representative specimens from eight participants were then inoculated into immunodeficient mice to test for infectivity. We used a linear mixed-effect model to analyse the dynamics of virus persistence in seminal fluid over time. We enrolled 26 participants and tested 130 seminal fluid specimens; median follow up was 197 days (IQR 187-209 days) after enrolment, which corresponded to 255 days (228-287) after disease onset. Ebola virus RNA was detected in 86 semen specimens from 19 (73%) participants. Median duration of Ebola virus RNA detection was 158 days after onset (73-181; maximum 407 days at end of follow-up). Mathematical modelling of the quantitative time-series data showed a mean clearance rate of Ebola virus RNA from seminal fluid of -0·58 log units per month, although the clearance kinetic varied greatly between participants. Using our biostatistical model, we predict that 50% and 90% of male survivors clear Ebola virus RNA from seminal fluid at 115 days (90% prediction interval 72-160) and 294 days (212-399) after disease onset, respectively. We also predicted that the number of men positive for Ebola virus RNA in affected countries would decrease from about 50 in January 2016, to fewer than 1 person by July, 2016. Infectious virus was detected in 15 of 26 (58%) specimens tested in mice. Time

Persistent Bovine Viral Diarrhea Virus infection in domestic and wild small ruminants and camelids including the mountain goat (Oreamnos americanus

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Danielle Darracq Nelson

2016-01-01

Full Text Available Bovine viral diarrhea virus (BVDV is a Pestivirus best known for causing a variety of disease syndromes in cattle, including gastrointestinal disease, reproductive insufficiency, immunosuppression, mucosal disease, and hemorrhagic syndrome. The virus can be spread by transiently infected individuals and by persistently infected animals that may be asymptomatic while shedding large amounts of virus throughout their lifetime. BVDV has been reported in over 40 domestic and free-ranging species, and persistent infection has been described in eight of those species: white-tailed deer, mule deer, eland, mousedeer, mountain goats, alpacas, sheep, and domestic swine. This paper reviews the various aspects of BVDV transmission, disease syndromes, diagnosis, control, and prevention, as well as examines BVDV infection in domestic and wild small ruminants and camelids including mountain goats (Oreamnos americanus.

Effects of Vector Backbone and Pseudotype on Lentiviral Vector-mediated Gene Transfer: Studies in Infant ADA-Deficient Mice and Rhesus Monkeys

Science.gov (United States)

Carbonaro Sarracino, Denise; Tarantal, Alice F; Lee, C Chang I.; Martinez, Michele; Jin, Xiangyang; Wang, Xiaoyan; Hardee, Cinnamon L; Geiger, Sabine; Kahl, Christoph A; Kohn, Donald B

2014-01-01

Systemic delivery of a lentiviral vector carrying a therapeutic gene represents a new treatment for monogenic disease. Previously, we have shown that transfer of the adenosine deaminase (ADA) cDNA in vivo rescues the lethal phenotype and reconstitutes immune function in ADA-deficient mice. In order to translate this approach to ADA-deficient severe combined immune deficiency patients, neonatal ADA-deficient mice and newborn rhesus monkeys were treated with species-matched and mismatched vectors and pseudotypes. We compared gene delivery by the HIV-1-based vector to murine γ-retroviral vectors pseudotyped with vesicular stomatitis virus-glycoprotein or murine retroviral envelopes in ADA-deficient mice. The vesicular stomatitis virus-glycoprotein pseudotyped lentiviral vectors had the highest titer and resulted in the highest vector copy number in multiple tissues, particularly liver and lung. In monkeys, HIV-1 or simian immunodeficiency virus vectors resulted in similar biodistribution in most tissues including bone marrow, spleen, liver, and lung. Simian immunodeficiency virus pseudotyped with the gibbon ape leukemia virus envelope produced 10- to 30-fold lower titers than the vesicular stomatitis virus-glycoprotein pseudotype, but had a similar tissue biodistribution and similar copy number in blood cells. The relative copy numbers achieved in mice and monkeys were similar when adjusted to the administered dose per kg. These results suggest that this approach can be scaled-up to clinical levels for treatment of ADA-deficient severe combined immune deficiency subjects with suboptimal hematopoietic stem cell transplantation options. PMID:24925206

Effects of vector backbone and pseudotype on lentiviral vector-mediated gene transfer: studies in infant ADA-deficient mice and rhesus monkeys.

Science.gov (United States)

Carbonaro Sarracino, Denise; Tarantal, Alice F; Lee, C Chang I; Martinez, Michele; Jin, Xiangyang; Wang, Xiaoyan; Hardee, Cinnamon L; Geiger, Sabine; Kahl, Christoph A; Kohn, Donald B

2014-10-01

Systemic delivery of a lentiviral vector carrying a therapeutic gene represents a new treatment for monogenic disease. Previously, we have shown that transfer of the adenosine deaminase (ADA) cDNA in vivo rescues the lethal phenotype and reconstitutes immune function in ADA-deficient mice. In order to translate this approach to ADA-deficient severe combined immune deficiency patients, neonatal ADA-deficient mice and newborn rhesus monkeys were treated with species-matched and mismatched vectors and pseudotypes. We compared gene delivery by the HIV-1-based vector to murine γ-retroviral vectors pseudotyped with vesicular stomatitis virus-glycoprotein or murine retroviral envelopes in ADA-deficient mice. The vesicular stomatitis virus-glycoprotein pseudotyped lentiviral vectors had the highest titer and resulted in the highest vector copy number in multiple tissues, particularly liver and lung. In monkeys, HIV-1 or simian immunodeficiency virus vectors resulted in similar biodistribution in most tissues including bone marrow, spleen, liver, and lung. Simian immunodeficiency virus pseudotyped with the gibbon ape leukemia virus envelope produced 10- to 30-fold lower titers than the vesicular stomatitis virus-glycoprotein pseudotype, but had a similar tissue biodistribution and similar copy number in blood cells. The relative copy numbers achieved in mice and monkeys were similar when adjusted to the administered dose per kg. These results suggest that this approach can be scaled-up to clinical levels for treatment of ADA-deficient severe combined immune deficiency subjects with suboptimal hematopoietic stem cell transplantation options.

Viral Small-RNA Analysis of Bombyx mori Larval Midgut during Persistent and Pathogenic Cytoplasmic Polyhedrosis Virus Infection

OpenAIRE

Zografidis, Aris; Van Nieuwerburgh, Filip; Kolliopoulou, Anna; Apostolou-Karampelis, Konstantinos; Head, Steven R.; Deforce, Dieter; Smagghe, Guy; Swevers, Luc

2015-01-01

The lepidopteran innate immune response against RNA viruses remains poorly understood, while in other insects several studies have highlighted an essential role for the exo-RNAi pathway in combating viral infection. Here, by using deep-sequencing technology for viral small-RNA (vsRNA) assessment, we provide evidence that exo-RNAi is operative in the silkworm Bombyx mori against both persistent and pathogenic infection of B. mori cytoplasmic polyhedrosis virus (BmCPV) which is characterized by...

Intrapulmonary Versus Nasal Transduction of Murine Airways With GP64-pseudotyped Viral Vectors

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Mayumi Oakland

2013-01-01

Full Text Available Persistent viral vector-mediated transgene expression in the airways requires delivery to cells with progenitor capacity and avoidance of immune responses. Previously, we observed that GP64-pseudotyped feline immunodeficiency virus (FIV-mediated gene transfer was more efficient in the nasal airways than the large airways of the murine lung. We hypothesized that in vivo gene transfer was limited by immunological and physiological barriers in the murine intrapulmonary airways. Here, we systematically investigate multiple potential barriers to lentiviral gene transfer in the airways of mice. We show that GP64-FIV vector transduced primary cultures of well-differentiated murine nasal epithelia with greater efficiency than primary cultures of murine tracheal epithelia. We further demonstrate that neutrophils, type I interferon (IFN responses, as well as T and B lymphocytes are not the major factors limiting the transduction of murine conducting airways. In addition, we observed better transduction of GP64-pseudotyped vesicular stomatitis virus (VSV in the nasal epithelia compared with the intrapulmonary airways in mice. VSVG glycoprotein pseudotyped VSV transduced intrapulmonary epithelia with similar efficiency as nasal epithelia. Our results suggest that the differential transduction efficiency of nasal versus intrapulmonary airways by FIV vector is not a result of immunological barriers or surface area, but rather differential expression of cellular factors specific for FIV vector transduction.

Persistent infections after natural transmission of bovine viral diarrhoea virus from cattle to goats and among goats

Science.gov (United States)

2013-01-01

Bovine viral diarrhoea virus (BVDV) is an economically important pathogen of cattle worldwide. Infection of a pregnant animal may lead to persistent infection of the foetus and birth of a persistently infected (PI) calf that sheds the virus throughout its life. However, BVD viruses are not strictly species specific. BVDV has been isolated from many domesticated and wild ruminants. This is of practical importance as virus reservoirs in non-bovine hosts may hamper BVDV control in cattle. A goat given as a social companion to a BVDV PI calf gave birth to a PI goat kid. In order to test if goat to goat infections were possible, seronegative pregnant goats were exposed to the PI goat. In parallel, seronegative pregnant goats were kept together with the PI calf. Only the goat to goat transmission resulted in the birth of a next generation of BVDV PI kids whereas all goats kept together with the PI calf aborted. To our knowledge, this is the first report which shows that a PI goat cannot only transmit BVD virus to other goats but that such transmission may indeed lead to the birth of a second generation of PI goats. Genetic analyses indicated that establishment in the new host species may be associated with step-wise adaptations in the viral genome. Thus, goats have the potential to be a reservoir for BVDV. However, the PI goats showed growth retardation and anaemia and their survival under natural conditions remains questionable. PMID:23675947

Persistent infections after natural transmission of bovine viral diarrhoea virus from cattle to goats and among goats.

Science.gov (United States)

Bachofen, Claudia; Vogt, Hans-Rudolf; Stalder, Hanspeter; Mathys, Tanja; Zanoni, Reto; Hilbe, Monika; Schweizer, Matthias; Peterhans, Ernst

2013-05-15

Bovine viral diarrhoea virus (BVDV) is an economically important pathogen of cattle worldwide. Infection of a pregnant animal may lead to persistent infection of the foetus and birth of a persistently infected (PI) calf that sheds the virus throughout its life. However, BVD viruses are not strictly species specific. BVDV has been isolated from many domesticated and wild ruminants. This is of practical importance as virus reservoirs in non-bovine hosts may hamper BVDV control in cattle. A goat given as a social companion to a BVDV PI calf gave birth to a PI goat kid. In order to test if goat to goat infections were possible, seronegative pregnant goats were exposed to the PI goat. In parallel, seronegative pregnant goats were kept together with the PI calf. Only the goat to goat transmission resulted in the birth of a next generation of BVDV PI kids whereas all goats kept together with the PI calf aborted. To our knowledge, this is the first report which shows that a PI goat cannot only transmit BVD virus to other goats but that such transmission may indeed lead to the birth of a second generation of PI goats. Genetic analyses indicated that establishment in the new host species may be associated with step-wise adaptations in the viral genome. Thus, goats have the potential to be a reservoir for BVDV. However, the PI goats showed growth retardation and anaemia and their survival under natural conditions remains questionable.

Persistence of highly pathogenic avian influenza virus (H7N1) in infected chickens: feather as a suitable sample for diagnosis.

Science.gov (United States)

Busquets, Núria; Abad, F Xavier; Alba, Anna; Dolz, Roser; Allepuz, Alberto; Rivas, Raquel; Ramis, Antonio; Darji, Ayub; Majó, Natàlia

2010-09-01

Selection of an ideal sample is a vital element in early detection of influenza infection. Rapid identification of infectious individuals or animals is crucial not only for avian influenza virus (AIV) surveillance programmes, but also for treatment and containment strategies. This study used a combination of quantitative real-time RT-PCR with an internal positive control and a cell-titration system to examine the presence of virus in different samples during active experimental AIV infection and its persistence in the infected carcasses. Oropharyngeal/cloacal swabs as well as feather pulp and blood samples were collected from 15-day-old chicks infected with H7N1 highly pathogenic AIV (HPAIV) and the kinetics of virus shedding during active infection were evaluated. Additionally, several samples (muscle, skin, brain, feather pulp and oropharyngeal and cloacal swabs) were examined to assess the persistence of virus in the HPAIV-infected carcasses. Based on the results, feather pulp was found to be the best sample to detect and isolate HPAIV from infected chicks from 24 h after inoculation onwards. Kinetic studies on the persistence of virus in infected carcasses revealed that tissues such as muscle could potentially transmit infectious virus for 3 days post-mortem (p.m.), whilst other tissues such as skin, feather pulp and brain retained their infectivity for as long as 5-6 days p.m. at environmental temperature (22-23 degrees C). These results strongly favour feather as a useful sample for HPAIV diagnosis in infected chickens as well as in carcasses.

Vector competence of the Aedes aegypti population from Santiago Island, Cape Verde, to different serotypes of dengue virus.

Science.gov (United States)

da Moura, Aires Januário Fernandes; de Melo Santos, Maria Alice Varjal; Oliveira, Claudia Maria Fontes; Guedes, Duschinka Ribeiro Duarte; de Carvalho-Leandro, Danilo; da Cruz Brito, Maria Lidia; Rocha, Hélio Daniel Ribeiro; Gómez, Lara Ferrero; Ayres, Constância Flávia Junqueira

2015-02-19

Dengue is an arboviral disease caused by dengue virus (DENV), whose main vectors are the mosquitoes Aedes aegypti and Aedes albopictus. A. aegypti is the only DENV vector in Cape Verde, an African country that suffered its first outbreak of dengue in 2009. However, little is known about the variation in the level of vector competence of this mosquito population to the different DENV serotypes. This study aimed to evaluate the vector competence of A. aegypti from the island of Santiago, Cape Verde, to four DENV serotypes and to detect DENV vertical transmission. Mosquitoes were fed on blood containing DENV serotypes and were dissected at 7, 14 and 21 days post-infection (dpi) to detect the virus in the midgut, head and salivary glands (SG) using RT-PCR. Additionally, the number of copies of viral RNA present in the SG was determined by qRT-PCR. Furthermore, eggs were collected in the field and adult mosquitoes obtained were analyzed by RT-PCR and the platelia dengue NS1 antigen kit to detect transovarial transmission. High rates of SG infection were observed for DENV-2 and DENV-3 whereas for DENV-1, viral RNA was only detected in the midgut and head. DENV-4 did not spread to the head or SG, maintaining the infection only in the midgut. The number of viral RNA copies in the SG did not vary significantly between DENV-2 and DENV-3 or among the different periods of incubation and the various titers of DENV tested. With respect to DENV surveillance in mosquitoes obtained from the eggs collected in the field, no samples were positive. Although no DENV positive samples were collected from the field in 2014, it is important to highlight that the A. aegypti population from Santiago Islands exhibited different degrees of susceptibility to DENV serotypes. This population showed a high vector competence for DENV-2 and DENV-3 strains and a low susceptibility to DENV-1 and DENV-4. Viral RNA copies in the SG remained constant for at least 21 dpi, which may enhance the vector

Using epidemiological information to develop effective integrated virus disease management strategies.

Science.gov (United States)

Jones, Roger A C

2004-03-01

Virus diseases cause serious losses in yield and quality of cultivated plants worldwide. These losses and the resulting financial damage can be limited by controlling epidemics using measures that minimise virus infection sources or suppress virus spread. For each combination of virus, cultivated plant and production system, there is an 'economic threshold' above which the financial damage is sufficient to justify using such measures. However, individual measures used alone may bring only small benefits and they may become ineffective, especially over the long term. When diverse control measures that act in different ways are combined and used together, their effects are complementary resulting in far more effective overall control. Such experiences have led to the development of integrated management concepts for virus diseases that combine available host resistance, cultural, chemical and biological control measures. Selecting the ideal mix of measures for each pathosystem and production situation requires detailed knowledge of the epidemiology of the causal virus and the mode of action of each individual control measure so that diverse responses can be devised to meet the unique features of each of the different scenarios considered. The strategies developed must be robust and necessitate minimal extra expense, labour demands and disruption to standard practices. Examples of how epidemiological information can be used to develop effective integrated disease management (IDM) strategies for diverse situations are described. They involve circumstances where virus transmission from plant-to-plant occurs in four different ways: by contact, non-persistently or persistently by insect vectors, and by root-infecting fungi. The examples are: Subterranean clover mottle virus (SCMoV) (contact-transmitted) and Bean yellow mosaic virus (BYMV) (non-persistently aphid-transmitted) in annually self-regenerating clover pasture; three seed-borne viruses (all non-persistently aphid

Antibody Persistence in Adults Two Years after Vaccination with an H1N1 2009 Pandemic Influenza Virus-Like Particle Vaccine.

Directory of Open Access Journals (Sweden)

Nuriban Valero-Pacheco

Full Text Available The influenza virus is a human pathogen that causes epidemics every year, as well as potential pandemic outbreaks, as occurred in 2009. Vaccination has proven to be sufficient in the prevention and containment of viral spreading. In addition to the current egg-based vaccines, new and promising vaccine platforms, such as cell culture-derived vaccines that include virus-like particles (VLPs, have been developed. VLPs have been shown to be both safe and immunogenic against influenza infections. Although antibody persistence has been studied in traditional egg-based influenza vaccines, studies on antibody response durations induced by VLP influenza vaccines in humans are scarce. Here, we show that subjects vaccinated with an insect cell-derived VLP vaccine, in the midst of the 2009 H1N1 influenza pandemic outbreak in Mexico City, showed antibody persistence up to 24 months post-vaccination. Additionally, we found that subjects that reported being revaccinated with a subsequent inactivated influenza virus vaccine showed higher antibody titres to the pandemic influenza virus than those who were not revaccinated. These findings provide insights into the duration of the antibody responses elicited by an insect cell-derived pandemic influenza VLP vaccine and the possible effects of subsequent influenza vaccination on antibody persistence induced by this VLP vaccine in humans.

[Activating effect of adrenaline, prednisolone and vincristine in the late periods of tick-borne encephalitis virus persistence].

Science.gov (United States)

Frolova, T V; Pogodina, V V

1984-01-01

The activating effect of adrenalin (A), prednisolone (P), and vincristine (V) on persistent infection caused by subcutaneous inoculation of Syrian hamsters with the Vasilchenko and B-383 strains of tick-borne encephalitis virus (TBE) was studied. The drugs were administered once, twice, or three times 250-270 days after virus inoculation. Complement-fixing antigen was found in the organs of the infected animals given no A, P, or V; in the organ explants synthesis of hemagglutinin was observed but no infectious virus could be isolated. After treatment of the infected hamsters with A, P, or V organ explants yielded TBE virus strains which showed either high or low virulence for white mice. The activated TBE virus strains were obtained from explants of hamster brains and spleens but not liver. V produced the most marked activating effect, A the least.

Culicoides (Diptera: Ceratopogonidae) midges, the vectors of African horse sickness virus--a host/vector contact study in the Niayes area of Senegal.

Science.gov (United States)

Fall, Moussa; Diarra, Maryam; Fall, Assane G; Balenghien, Thomas; Seck, Momar T; Bouyer, Jérémy; Garros, Claire; Gimonneau, Geoffrey; Allène, Xavier; Mall, Iba; Delécolle, Jean-Claude; Rakotoarivony, Ignace; Bakhoum, Mame T; Dusom, Ange M; Ndao, Massouka; Konaté, Lassana; Faye, Ousmane; Baldet, Thierry

2015-01-21

African horse sickness (AHS) is an equine disease endemic to Senegal. The African horse sickness virus (AHSV) is transmitted to the mammalian hosts by midges of the Culicoides Latreille genus. During the last epizootic outbreak of AHS in Senegal in 2007, 1,169 horses died from this disease entailing an estimated cost of 1.4 million euros. In spite of the serious animal health and economic implications of AHS, very little is known about determinants involved in transmission such as contact between horses and the Culicoides species suspected of being its vectors. The monthly variation in host/vector contact was determined in the Niayes area, Senegal, an area which was severely affected by the 2007 outbreak of AHS. A horse-baited trap and two suction light traps (OVI type) were set up at each of five sites for three consecutive nights every month for one year. Of 254,338 Culicoides midges collected 209,543 (82.4%) were female and 44,795 (17.6%) male. Nineteen of the 41 species collected were new distribution records for Senegal. This increased the number of described Culicoides species found in Senegal to 53. Only 19 species, of the 41 species found in light trap, were collected in the horse-baited trap (23,669 specimens) largely dominated by Culicoides oxystoma (22,300 specimens, i.e. 94.2%) followed by Culicoides imicola (482 specimens, i.e. 2.0%) and Culicoides kingi (446 specimens, i.e. 1.9%). Culicoides oxystoma should be considered as a potential vector of AHSV in the Niayes area of Senegal due to its abundance on horses and its role in the transmission of other Culicoides-borne viruses.

Vector-Host Interactions of Culiseta melanura in a Focus of Eastern Equine Encephalitis Virus Activity in Southeastern Virginia.

Science.gov (United States)

Molaei, Goudarz; Armstrong, Philip M; Abadam, Charles F; Akaratovic, Karen I; Kiser, Jay P; Andreadis, Theodore G

2015-01-01

Eastern equine encephalitis virus (EEEV) causes a highly pathogenic mosquito-borne zoonosis that is responsible for sporadic outbreaks of severe illness in humans and equines in the eastern USA. Culiseta (Cs.) melanura is the primary vector of EEEV in most geographic regions but its feeding patterns on specific avian and mammalian hosts are largely unknown in the mid-Atlantic region. The objectives of our study were to: 1) identify avian hosts of Cs. melanura and evaluate their potential role in enzootic amplification of EEEV, 2) assess spatial and temporal patterns of virus activity during a season of intense virus transmission, and 3) investigate the potential role of Cs. melanura in epidemic/epizootic transmission of EEEV to humans and equines. Accordingly, we collected mosquitoes at 55 sites in Suffolk, Virginia in 2013, and identified the source of blood meals in engorged mosquitoes by nucleotide sequencing PCR products of the mitochondrial cytochrome b gene. We also examined field-collected mosquitoes for evidence of infection with EEEV using Vector Test, cell culture, and PCR. Analysis of 188 engorged Cs. melanura sampled from April through October 2013 indicated that 95.2%, 4.3%, and 0.5% obtained blood meals from avian, mammalian, and reptilian hosts, respectively. American Robin was the most frequently identified host for Cs. melanura (42.6% of blood meals) followed by Northern Cardinal (16.0%), European Starling (11.2%), Carolina Wren (4.3%), and Common Grackle (4.3%). EEEV was detected in 106 mosquito pools of Cs. melanura, and the number of virus positive pools peaked in late July with 22 positive pools and a Maximum Likelihood Estimation (MLE) infection rate of 4.46 per 1,000 mosquitoes. Our findings highlight the importance of Cs. melanura as a regional EEEV vector based on frequent feeding on virus-competent bird species. A small proportion of blood meals acquired from mammalian hosts suggests the possibility that this species may occasionally

Forced recombination of psi-modified murine leukaemia virus-based vectors with murine leukaemia-like and VL30 murine endogenous retroviruses

DEFF Research Database (Denmark)

Mikkelsen, J G; Lund, Anders Henrik; Duch, M

1999-01-01

Co-encapsidation of retroviral RNAs into virus particles allows for the generation of recombinant proviruses through events of template switching during reverse transcription. By use of a forced recombination system based on recombinational rescue of replication- defective primer binding site-imp....... We note that recombination-based rescue of primer binding site knock-out retroviral vectors may constitute a sensitive assay to register putative genetic interactions involving endogenous retroviral RNAs present in cells of various species.......-impaired Akv-MLV-derived vectors, we here examine putative genetic interactions between vector RNAs and copackaged endogenous retroviral RNAs of the murine leukaemia virus (MLV) and VL30 retroelement families. We show (i) that MLV recombination is not blocked by nonhomology within the 5' untranslated region...... harbouring the supposed RNA dimer-forming cis -elements and (ii) that copackaged retroviral RNAs can recombine despite pronounced sequence dissimilarity at the cross-over site(s) and within parts of the genome involved in RNA dimerization, encapsidation and strand transferring during reverse transcription...

Role of complement and antibodies in controlling infection with pathogenic simian immunodeficiency virus (SIV in macaques vaccinated with replication-deficient viral vectors

Directory of Open Access Journals (Sweden)

Strasak Alexander

2009-06-01

Full Text Available Abstract Background We investigated the interplay between complement and antibodies upon priming with single-cycle replicating viral vectors (SCIV encoding SIV antigens combined with Adeno5-SIV or SCIV pseudotyped with murine leukemia virus envelope boosting strategies. The vaccine was applied via spray-immunization to the tonsils of rhesus macaques and compared with systemic regimens. Results Independent of the application regimen or route, viral loads were significantly reduced after challenge with SIVmac239 (p Conclusion The heterologous prime-boost strategy with replication-deficient viral vectors administered exclusively via the tonsils did not induce any neutralizing antibodies before challenge. However, after challenge, comparable SIV-specific humoral immune responses were observed in all vaccinated animals. Immunization with single cycle immunodeficiency viruses mounts humoral immune responses comparable to live-attenuated immunodeficiency virus vaccines.

Mapping the basic reproduction number (Ro) for vector-borne diseases: A case study on bluetongue virus.

NARCIS (Netherlands)

Hartemink, N.; Purse, B.V.; Meiswinkel, R.; Brown, H.E.; Koeijer, de A.A.; Elbers, A.R.W.; Boender, G.J.; Rogers, D.J.; Heesterbeek, J.A.P.

2009-01-01

Geographical maps indicating the value of the basic reproduction number, R0, can be used to identify areas of higher risk for an outbreak after an introduction. We develop a methodology to create R0 maps for vector-borne diseases, using bluetongue virus as a case study. This method provides a tool

Vector Competence of French Polynesian Aedes aegypti and Aedes polynesiensis for Zika Virus.

Directory of Open Access Journals (Sweden)

Vaea Richard

2016-09-01

Full Text Available In 2013-2014, French Polynesia experienced for the first time a Zika outbreak. Two Aedes mosquitoes may have contributed to Zika virus (ZIKV transmission in French Polynesia: the worldwide distributed Ae. aegypti and the Polynesian islands-endemic Ae. polynesiensis mosquito.To evaluate their vector competence for ZIKV, mosquitoes were infected per os at viral titers of 7 logs tissue culture infectious dose 50%. At several days post-infection (dpi, saliva was collected from each mosquito and inoculated onto C6/36 mosquito cells to check for the presence of ZIKV infectious particles. Legs and body of each mosquito were also collected and submitted separately to RNA extraction and ZIKV RT-PCR. In Ae. aegypti the infection rate was high as early as 6 dpi and the dissemination efficiency get substantial from 9 dpi while the both rates remained quite low in Ae. polynesiensis. The transmission efficiency was poor in Ae. aegypti until 14 dpi and no infectious saliva was found in Ae. polynesiensis at the time points studied.In our experimental conditions, the late ability of the French Polynesian Ae. aegypti to transmit ZIKV added by the poor competence of Ae. polynesiensis for this virus suggest the possible contribution of another vector for the propagation of ZIKV during the outbreak, in particular in remote islands where Ae. polynesiensis is predominating.

Curing of foot-and-mouth disease virus from persistently infected cells by ribavirin involves enhanced mutagenesis

International Nuclear Information System (INIS)

Airaksinen, Antero; Pariente, Nonia; Menendez-Arias, Luis; Domingo, Esteban

2003-01-01

BHK-21 cells persistently infected with foot-and-mouth disease virus (FMDV) can be cured of virus by treatment with the antiviral nucleoside analogue ribavirin. To study whether the process involved an increase in the number of mutations in the mutant spectrum of the viral population, viral genomes were cloned from persistently infected cells treated or untreated with ribavirin. An increase of up to 10-fold in mutation frequencies associated with ribavirin treatment was observed in the viral genomes from the treated cultures as compared with parallel, untreated cultures. To address the possible mechanisms of enhanced mutagenesis, we investigated the mutagenic effects of ribavirin together with guanosine, and mycophenolic acid in the presence or absence of guanosine. Changes in the intracellular nucleotide concentrations were determined for all treatments. The results suggest that the increased mutation frequencies were not dependent on nucleotide pool imbalances or due to selection of preexisting genomes but they were produced by a mutagenic action of ribavirin

Prospects for Foamy Viral Vector Anti-HIV Gene Therapy

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Arun K. Nalla

2016-03-01

Full Text Available Stem cell gene therapy approaches for Human Immunodeficiency Virus (HIV infection have been explored in clinical trials and several anti-HIV genes delivered by retroviral vectors were shown to block HIV replication. However, gammaretroviral and lentiviral based retroviral vectors have limitations for delivery of anti-HIV genes into hematopoietic stem cells (HSC. Foamy virus vectors have several advantages including efficient delivery of transgenes into HSC in large animal models, and a potentially safer integration profile. This review focuses on novel anti-HIV transgenes and the potential of foamy virus vectors for HSC gene therapy of HIV.

Hepatitis virus protein X-Phenylalanine Hydroxylase fusion proteins identified in PKU mice treated with AAV-WPRE vectors

Science.gov (United States)

Utilizing the Pahenu2 mouse model for phenylketonuria (PKU), we developed an improved expression vector containing the Woodchuck Hepatitis Virus post-transcriptional regulatory element inserted into a rAAV-mPAH construct (rAAV-mPAH-WPRE) for treatment of PKU. Following portal vein delivery of these ...

Insights into persistence mechanisms of a zoonotic virus in bat colonies using a multispecies metapopulation model.

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Margarita Pons-Salort

Full Text Available Rabies is a worldwide zoonosis resulting from Lyssavirus infection. In Europe, Eptesicus serotinus is the most frequently reported bat species infected with Lyssavirus, and thus considered to be the reservoir of European bat Lyssavirus type 1 (EBLV-1. To date, the role of other bat species in EBLV-1 epidemiology and persistence remains unknown. Here, we built an EBLV-1-transmission model based on local observations of a three-cave and four-bat species (Myotis capaccinii, Myotis myotis, Miniopterus schreibersii, Rhinolophus ferrumequinum system in the Balearic Islands, for which a 1995-2011 serological dataset indicated the continuous presence of EBLV-1. Eptesicus serotinus was never observed in the system during the 16-year follow-up and therefore was not included in the model. We used the model to explore virus persistence mechanisms and to assess the importance of each bat species in the transmission dynamics. We found that EBLV-1 could not be sustained if transmission between M. schreibersii and other bat species was eliminated, suggesting that this species serves as a regional reservoir. Global sensitivity analysis using Sobol's method revealed that following the rate of autumn-winter infectious contacts, M. schreibersii's incubation- and immune-period durations, but not the infectious period length, were the most relevant factors driving virus persistence.

Insights into Persistence Mechanisms of a Zoonotic Virus in Bat Colonies Using a Multispecies Metapopulation Model

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Pons-Salort, Margarita; Serra-Cobo, Jordi; Jay, Flora; López-Roig, Marc; Lavenir, Rachel; Guillemot, Didier; Letort, Véronique; Bourhy, Hervé; Opatowski, Lulla

2014-01-01

Rabies is a worldwide zoonosis resulting from Lyssavirus infection. In Europe, Eptesicus serotinus is the most frequently reported bat species infected with Lyssavirus, and thus considered to be the reservoir of European bat Lyssavirus type 1 (EBLV-1). To date, the role of other bat species in EBLV-1 epidemiology and persistence remains unknown. Here, we built an EBLV-1−transmission model based on local observations of a three-cave and four-bat species (Myotis capaccinii, Myotis myotis, Miniopterus schreibersii, Rhinolophus ferrumequinum) system in the Balearic Islands, for which a 1995–2011 serological dataset indicated the continuous presence of EBLV-1. Eptesicus serotinus was never observed in the system during the 16-year follow-up and therefore was not included in the model. We used the model to explore virus persistence mechanisms and to assess the importance of each bat species in the transmission dynamics. We found that EBLV-1 could not be sustained if transmission between M. schreibersii and other bat species was eliminated, suggesting that this species serves as a regional reservoir. Global sensitivity analysis using Sobol's method revealed that following the rate of autumn−winter infectious contacts, M. schreibersii's incubation- and immune-period durations, but not the infectious period length, were the most relevant factors driving virus persistence. PMID:24755619

Disabled infectious single cycle-herpes simplex virus (DISC-HSV) as a vector for immunogene therapy of cancer.

Science.gov (United States)

Rees, Robert C; McArdle, Stephanie; Mian, Shahid; Li, Geng; Ahmad, Murrium; Parkinson, Richard; Ali, Selman A

2002-02-01

Disabled infectious single cycle-herpes simplex viruses (DISC-HSV) have been shown to be safe for use in humans and may be considered efficacious as vectors for immunogene therapy in cancer. Preclinical studies show that DISC-HSV is an efficient delivery system for cytokine genes and antigens. DISC-HSV infects a high proportion of cells, resulting in rapid gene expression for at least 72 h. The DISC-HSV-mGM-CSF vector, when inoculated into tumors, induces tumor regression in a high percentage of animals, concomitant with establishing a cytotoxic T-cell response, which is MHC class I restricted and directed against peptides of known tumor antigens. The inherent properties of DISC-HSV makes it a suitable vector for consideration in human immunogene therapy trials.

An efficient viral vector for functional genomic studies of Prunus fruit trees and its induced resistance to Plum pox virus via silencing of a host factor gene.

Science.gov (United States)

Cui, Hongguang; Wang, Aiming

2017-03-01

RNA silencing is a powerful technology for molecular characterization of gene functions in plants. A commonly used approach to the induction of RNA silencing is through genetic transformation. A potent alternative is to use a modified viral vector for virus-induced gene silencing (VIGS) to degrade RNA molecules sharing similar nucleotide sequence. Unfortunately, genomic studies in many allogamous woody perennials such as peach are severely hindered because they have a long juvenile period and are recalcitrant to genetic transformation. Here, we report the development of a viral vector derived from Prunus necrotic ringspot virus (PNRSV), a widespread fruit tree virus that is endemic in all Prunus fruit production countries and regions in the world. We show that the modified PNRSV vector, harbouring the sense-orientated target gene sequence of 100-200 bp in length in genomic RNA3, could efficiently trigger the silencing of a transgene or an endogenous gene in the model plant Nicotiana benthamiana. We further demonstrate that the PNRSV-based vector could be manipulated to silence endogenous genes in peach such as eukaryotic translation initiation factor 4E isoform (eIF(iso)4E), a host factor of many potyviruses including Plum pox virus (PPV). Moreover, the eIF(iso)4E-knocked down peach plants were resistant to PPV. This work opens a potential avenue for the control of virus diseases in perennial trees via viral vector-mediated silencing of host factors, and the PNRSV vector may serve as a powerful molecular tool for functional genomic studies of Prunus fruit trees. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Superior infectivity for mosquito vectors contributes to competitive displacement among strains of dengue virus

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Schirtzinger Erin E

2008-02-01

Full Text Available Abstract Background Competitive displacement of a weakly virulent pathogen strain by a more virulent strain is one route to disease emergence. However the mechanisms by which pathogens compete for access to hosts are poorly understood. Among vector-borne pathogens, variation in the ability to infect vectors may effect displacement. The current study focused on competitive displacement in dengue virus serotype 3 (DENV3, a mosquito-borne pathogen of humans. In Sri Lanka in the 1980's, a native DENV3 strain associated with relatively mild dengue disease was displaced by an invasive DENV3 strain associated with the most severe disease manifestations, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS, resulting in an outbreak of DHF/DSS. Here we tested the hypothesis that differences between the invasive and native strain in their infectivity for Aedes aegypti mosquitoes, the primary vector of DENV, contributed to the competitive success of the invasive strain Results To be transmitted by a mosquito, DENV must infect and replicate in the midgut, disseminate into the hemocoel, infect the salivary glands, and be released into the saliva. The ability of the native and invasive DENV3 strains to complete the first three steps of this process in Aedes aegypti mosquitoes was measured in vivo. The invasive strain infected a similar proportion of mosquitoes as the native strain but replicated to significantly higher titers in the midgut and disseminated with significantly greater efficiency than the native strain. In contrast, the native and invasive strain showed no significant difference in replication in cultured mosquito, monkey or human cells. Conclusion The invasive DENV3 strain infects and disseminates in Ae. aegypti more efficiently than the displaced native DENV3 strain, suggesting that the invasive strain is transmitted more efficiently. Replication in cultured cells did not adequately characterize the known phenotypic differences between

Destructive arthritis in a patient with chikungunya virus infection with persistent specific IgM antibodies

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Receveur Marie-Catherine

2009-12-01

Full Text Available Abstract Background Chikungunya fever is an emerging arboviral disease characterized by an algo-eruptive syndrome, inflammatory polyarthralgias, or tenosynovitis that can last for months to years. Up to now, the pathophysiology of the chronic stage is poorly understood. Case presentation We report the first case of CHIKV infection with chronic associated rheumatism in a patient who developed progressive erosive arthritis with expression of inflammatory mediators and persistence of specific IgM antibodies over 24 months following infection. Conclusions Understanding the specific features of chikungunya virus as well as how the virus interacts with its host are essential for the prevention, treatment or cure of chikungunya disease.

A safe and efficient BCG vectored vaccine to prevent the disease caused by the human Respiratory Syncytial Virus.

Science.gov (United States)

Rey-Jurado, Emma; Soto, Jorge; Gálvez, Nicolás; Kalergis, Alexis M

2017-09-02

The human Respiratory Syncytial Virus (hRSV) causes lower respiratory tract infections including pneumonia and bronchiolitis. Such infections also cause a large number of hospitalizations and affects mainly newborns, young children and the elderly worldwide. Symptoms associated with hRSV infection are due to an exacerbated immune response characterized by low levels of IFN-γ, recruitment of neutrophils and eosinophils to the site of infection and lung damage. Although hRSV is a major health problem, no vaccines are currently available. Different immunization approaches have been developed to achieve a vaccine that activates the immune system, without triggering an unbalanced inflammation. These approaches include live attenuated vaccine, DNA or proteins technologies, and the use of vectors to express proteins of the virus. In this review, we discuss the host immune response to hRSV and the immunological mechanisms underlying an effective and safe BCG vectored vaccine against hRSV.

The yellow fever 17D vaccine virus: molecular basis of viral attenuation and its use as an expression vector

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Galler R.

1997-01-01

Full Text Available The yellow fever (YF virus is the prototype flavivirus. The use of molecular techniques has unraveled the basic mechanisms of viral genome structure and expression. Recent trends in flavivirus research include the use of infectious clone technology with which it is possible to recover virus from cloned cDNA. Using this technique, mutations can be introduced at any point of the viral genome and their resulting effect on virus phenotype can be assessed. This approach has opened new possibilities to study several biological viral features with special emphasis on the issue of virulence/attenuation of the YF virus. The feasibility of using YF virus 17D vaccine strain, for which infectious cDNA is available, as a vector for the expression of heterologous antigens is reviewed

The impact of temperature and Wolbachia infection on vector competence of potential dengue vectors Aedes aegypti and Aedes albopictus in the transmission of dengue virus serotype 1 in southern Taiwan.

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Tsai, Cheng-Hui; Chen, Tien-Huang; Lin, Cheo; Shu, Pei-Yun; Su, Chien-Ling; Teng, Hwa-Jen

2017-11-07

We evaluated the impact of temperature and Wolbachia infection on vector competence of the local Aedes aegypti and Ae. albopictus populations of southern Taiwan in the laboratory. After oral infection with dengue serotype 1 virus (DENV-1), female mosquitoes were incubated at temperatures of 10, 16, 22, 28 and 34 °C. Subsequently, salivary gland, head, and thorax-abdomen samples were analyzed for their virus titer at 0, 5, 10, 15, 20, 25 and 30 days post-infection (dpi) by real-time RT-PCR. The results showed that Ae. aegypti survived significantly longer and that dengue viral genome levels in the thorax-abdomen (10 3.25 ± 0.53 -10 4.09 ± 0.71 PFU equivalents/ml) and salivary gland samples (10 2.67 ± 0.33 -10 3.89 ± 0.58 PFU equivalents/ml) were significantly higher at high temperature (28-34 °C). The survival of Ae. albopictus was significantly better at 16 or 28 °C, but the virus titers from thorax-abdomen (10 0.70 -10 2.39 ± 1.31 PFU equivalents/ml) and salivary gland samples (10 0.12 ± 0.05 -10 1.51 ± 0.31 PFU equivalents/ml) were significantly higher at 22-28 °C. Within viable temperature ranges, the viruses were detectable after 10 dpi in salivary glands and head tissues in Ae. aegypti and after 5-10 dpi in Ae. albopictus. Vector competence was measured in Ae. albopictus with and without Wolbachia at 28 °C. Wolbachia-infected mosquitoes survived significantly better and carried lower virus titers than Wolbachia-free mosquitoes. Wolbachia coinfections (92.8-97.2%) with wAlbA and wAlbB strains were commonly found in a wild population of Ae. albopictus. In southern Taiwan, Ae. aegypti is the main vector of dengue and Ae. albopictus has a non-significant role in the transmission of dengue virus due to the high prevalence of Wolbachia infection in the local mosquito population of southern Taiwan.

Major emerging vector-borne zoonotic diseases of public health importance in Canada.

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Kulkarni, Manisha A; Berrang-Ford, Lea; Buck, Peter A; Drebot, Michael A; Lindsay, L Robbin; Ogden, Nicholas H

2015-06-10

In Canada, the emergence of vector-borne diseases may occur via international movement and subsequent establishment of vectors and pathogens, or via northward spread from endemic areas in the USA. Re-emergence of endemic vector-borne diseases may occur due to climate-driven changes to their geographic range and ecology. Lyme disease, West Nile virus (WNV), and other vector-borne diseases were identified as priority emerging non-enteric zoonoses in Canada in a prioritization exercise conducted by public health stakeholders in 2013. We review and present the state of knowledge on the public health importance of these high priority emerging vector-borne diseases in Canada. Lyme disease is emerging in Canada due to range expansion of the tick vector, which also signals concern for the emergence of human granulocytic anaplasmosis, babesiosis, and Powassan virus. WNV has been established in Canada since 2001, with epidemics of varying intensity in following years linked to climatic drivers. Eastern equine encephalitis virus, Jamestown Canyon virus, snowshoe hare virus, and Cache Valley virus are other mosquito-borne viruses endemic to Canada with the potential for human health impact. Increased surveillance for emerging pathogens and vectors and coordinated efforts among sectors and jurisdictions will aid in early detection and timely public health response.

Influenza a virus migration and persistence in North American wild birds.

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Justin Bahl

Full Text Available Wild birds have been implicated in the emergence of human and livestock influenza. The successful prediction of viral spread and disease emergence, as well as formulation of preparedness plans have been hampered by a critical lack of knowledge of viral movements between different host populations. The patterns of viral spread and subsequent risk posed by wild bird viruses therefore remain unpredictable. Here we analyze genomic data, including 287 newly sequenced avian influenza A virus (AIV samples isolated over a 34-year period of continuous systematic surveillance of North American migratory birds. We use a Bayesian statistical framework to test hypotheses of viral migration, population structure and patterns of genetic reassortment. Our results reveal that despite the high prevalence of Charadriiformes infected in Delaware Bay this host population does not appear to significantly contribute to the North American AIV diversity sampled in Anseriformes. In contrast, influenza viruses sampled from Anseriformes in Alberta are representative of the AIV diversity circulating in North American Anseriformes. While AIV may be restricted to specific migratory flyways over short time frames, our large-scale analysis showed that the long-term persistence of AIV was independent of bird flyways with migration between populations throughout North America. Analysis of long-term surveillance data provides vital insights to develop appropriately informed predictive models critical for pandemic preparedness and livestock protection.

Resting lymphocyte transduction with measles virus glycoprotein pseudotyped lentiviral vectors relies on CD46 and SLAM

International Nuclear Information System (INIS)

Zhou Qi; Schneider, Irene C.; Gallet, Manuela; Kneissl, Sabrina; Buchholz, Christian J.

2011-01-01

The measles virus (MV) glycoproteins hemagglutinin (H) and fusion (F) were recently shown to mediate transduction of resting lymphocytes by lentiviral vectors. MV vaccine strains use CD46 or signaling lymphocyte activation molecule (SLAM) as receptor for cell entry. A panel of H protein mutants derived from vaccine strain or wild-type MVs that lost or gained CD46 or SLAM receptor usage were investigated for their ability to mediate gene transfer into unstimulated T lymphocytes. The results demonstrate that CD46 is sufficient for efficient vector particle association with unstimulated lymphocytes. For stable gene transfer into these cells, however, both MV receptors were found to be essential.

The feasibility of rabies virus-vectored immunocontraception in a mouse model

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Xianfu Wu

2014-01-01

Full Text Available Immunocontraceptive vaccines may be an alternative to surgical sterilization. Dual rabies vaccination and dog population management is a helpful tool for rabies prevention. A synthetic gonadotropin-releasing hormone (GnRH peptide coupled to a carrier protein or T cell epitope is efficacious in inducing immunocontraception in a variety of mammals. However, virus-vectored GnRH recombinant vaccines have advantages over the conjugation method. In a previous in vitro study, we were able to insert a GnRH-coding sequence into the rabies virus (RABV glycoprotein (G gene, and the recombinant viruses grew to high titers in cells. Here, we further focused on the RABV G in accepting various copy numbers of GnRH. We demonstrated although RABV G protein with up to 4 copies of GnRH was well expressed, the recombinant virus was recovered only when 2 copies of GnRH (20 amino acids were incorporated into the G, indicating a possible insertion limit in making a full infectious clone. The investigation provides insight into the utility of RABV G as a carrier for small peptides and its suitability for vaccine studies. Following our previous study, we selected ERAg3p/2GnRH and tested the construct in mice. The vaccine induced ⩾80% infertility after three doses without any adjuvant, in live (8 of 10 mice infertility or inactivated (13 of 14 mice infertility formulations; while the pregnancy rate was 100% (10 of 10 mice in the controls. This initial success of immunocontraception in mice is promising, and we are now optimizing the vaccine formulation by using adjuvants and exploring novel delivery methods to minimize the dosage.

Biosynthesis of measles virus hemagglutinin in persistently infected cells

International Nuclear Information System (INIS)

Bellini, W.J.; Silver, G.D.; McFarlin, D.E.

1983-01-01

The synthesis of the hemagglutinin (HA) glycoprotein of measles virus was investigated in a persistently infected cell line using a monoclonal anti-HA. The synthesis of the HA protein was shown to be associated with the rough endoplasmic reticulum. The unglycosylated (HA 0 ) apoprotein is synthesized as a 65.000 dalton peptide and is inserted into the rough endoplasmic reticulum as a transmembrane protein with approximately 2 to 3000 daltons of the peptide exposed to the cytoplasmic membrane surface. Primary glycosylation of the HA protein was found to occur through the lipid-linked carrier, dolichol-phosphate, as determined by inhibition of glycosylation by tunicamycin. Glycosylation, however, was not a prerequisite for membrane insertion. Endo-β-N-acetyl-Glucosaminidase H digestion of the fully glycosylated HA protein indicated that both simple and complex oligosaccharides are present on the surface glycoprotein. (Author)

PEMERIKSAAN VIRUS DENGUE-3 PADA NYAMUK Aedes aegypti YANG DIINFEKSI SECARA INTRATHORAKAL DENGAN TEKNIK IMUNOSITOKIMIA MENGGUNAKAN ANTIBODI DSSE10

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Dyah Widiastuti

2013-09-01

Full Text Available ABSTRACTDengue viruses, globally the most prevalent arboviruses, are transmitted to humans by persistently infectedAedes mosquitoes. The most important vector of Dengue virus is the mosquito Ae.aegypti, which should be the main targetof surveillance and control activities. Virologic surveillance for dengue viruses in its vector has been used as an earlywarning system to predict outbreaks. Detection of Dengue virus antigen in mosquito head squash usingimmunocytochemical streptavidin biotin peroxidase complex (SBPC assay is an alternative method for dengue vectorsurveillance. The study aimed to develope immunocytochemical SBPC assay to detect Dengue virus infection in headsquash of Ae.aegypti. The study design was experimental. Artificially-infected adult Ae. aegypti mosquitoes of DENV 3were used as infectious samples and non-infected adult Ae. aegypti mosquitoes were used as normal ones. Theimmunocytochemical SBPC assay using monoclonal antibody DSSE10 then was applied in mosquito head squash todetect Dengue virus antigen. The results were analyzed by descriptive analysis. The immunocytochemical SBPC assaycan detect Dengue virus antigen in mosquito head squash at day 2 postinfection. There are some false positive resultsfound in immunocytochemical SBPC assay.Key Word: Dengue, immunocytochemistry, DSSE10

Dynamical roguing model for controlling the spread of tungro virus via Nephotettix Virescens in a rice field

Science.gov (United States)

Blas, Nikki; David, Guido

2017-10-01

Rice tungro disease is described as a cancer due to its major impact on the livelihood of farmers and the difficulty of controlling it. Tungro is a semi-persistent virus transmitted by green leafhoppers called Nephotettix Virescens. In this paper, we presented a compartmental plant-vector model of the Nephotettix Virescens - rice plant interaction based on a system of ordinary differential equations to simulate the effects of roguing in controlling the spread of Tungro virus in a model rice field of susceptible rice variety (Taichung Native 1).

Agricultural intensification, priming for persistence and the emergence of Nipah virus: a lethal bat-borne zoonosis.

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Pulliam, Juliet R C; Epstein, Jonathan H; Dushoff, Jonathan; Rahman, Sohayati A; Bunning, Michel; Jamaluddin, Aziz A; Hyatt, Alex D; Field, Hume E; Dobson, Andrew P; Daszak, Peter

2012-01-07

Emerging zoonoses threaten global health, yet the processes by which they emerge are complex and poorly understood. Nipah virus (NiV) is an important threat owing to its broad host and geographical range, high case fatality, potential for human-to-human transmission and lack of effective prevention or therapies. Here, we investigate the origin of the first identified outbreak of NiV encephalitis in Malaysia and Singapore. We analyse data on livestock production from the index site (a commercial pig farm in Malaysia) prior to and during the outbreak, on Malaysian agricultural production, and from surveys of NiV's wildlife reservoir (flying foxes). Our analyses suggest that repeated introduction of NiV from wildlife changed infection dynamics in pigs. Initial viral introduction produced an explosive epizootic that drove itself to extinction but primed the population for enzootic persistence upon reintroduction of the virus. The resultant within-farm persistence permitted regional spread and increased the number of human infections. This study refutes an earlier hypothesis that anomalous El Niño Southern Oscillation-related climatic conditions drove emergence and suggests that priming for persistence drove the emergence of a novel zoonotic pathogen. Thus, we provide empirical evidence for a causative mechanism previously proposed as a precursor to widespread infection with H5N1 avian influenza and other emerging pathogens.

Use of a simian virus 40-based shuttle vector to analyze enhanced mutagenesis in mitomycin C-treated monkey cells

International Nuclear Information System (INIS)

Roilides, E.; Munson, P.J.; Levine, A.S.; Dixon, K.

1988-01-01

When monkey cells were treated with mitomycin C 24 h before transfection with UV-irradiated pZ189 (a simian virus 40-based shuttle vector), there was a twofold increase in the frequency of mutations in the supF gene of the vector. These results suggest the existence of an enhancible mutagenesis pathway in mammalian cells. However, DNA sequence analysis of the SupF- mutants suggested no dramatic changes in the mechanisms of mutagenesis due to mitomycin C treatment of the cells

Diseño y construcción de vectores de transferencia para la obtención de virus vaccinia Ankara modificado (MVA recombinantes Design and construction of transfer vectors in order to obtain recombinant modified vaccinia virus Ankara (MVA

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M. F. Ferrer

2007-09-01

Full Text Available El virus vaccinia Ankara modificado (MVA constituye un buen candidato para el desarrollo de vectores virales de expresión no replicativos porque no replica en la mayoría de las células de mamíferos. Para la producción de MVA recombinantes es fundamental disponer de vectores de transferencia que, por recombinación homóloga con el genoma viral, permitan introducir los genes de interés en regiones no esenciales para la replicación in vitro. En este trabajo se diseñaron y obtuvieron los vectores de transferencia denominados VT-MHA y VT-MTK que portan las regiones correspondientes a las posiciones 1-303 y 608-948 del gen MVA165R y 1-244 y 325-534 del gen MVA086R, respectivamente, las que flanquean un sitio de clonado múltiple para la inserción de los genes foráneos. En dichos vectores se clonaron los casetes para la expresión de los genes lac Z o uid A, y la actividad de las enzimas marcadoras b-galactosidasa y b-glucuronidasa se confirmó in situ. Además, utilizando el vector denominado VT-MTK-GUS, se obtuvieron y aislaron MVA recombinantes puros que portan y expresan el gen uid A. Los resultados obtenidos constituyen las herramientas básicas para establecer la metodología de obtención de MVA recombinantes, con el propósito de desarrollar localmente vectores virales no replicativos candidatos a vacunas.Modified Vaccinia virus Ankara (MVA constitutes a good candidate for the development of non-replicative expression viral vectors because it does not replicate in most of mammalian cells. It is essential, for the production of recombinant MVA, the availability of transfer vectors which allow the introduction of desired genes into non-essential regions for in vitro viral replication, by homologous recombination with the viral genome. In the present work, the transfer vectors named VT-MHA and VT-MTK were designed and obtained. They carried genomic regions corresponding to 1- 303 and 608-948 positions of the MVA165R gene and 1-244 and

Viral Vectors for Use in the Development of Biodefense Vaccines

National Research Council Canada - National Science Library

Lee, John S; Hadjipanayis, Angela G; Parker, Michael D

2005-01-01

... agents of bioterrorism or biowarfare. The use of viruses, for example adenovirus, vaccinia virus, and Venezuelan equine encephalitis virus, as vaccine-vectors has enabled researchers to develop effective means for countering the threat of bioterrorism and biowarfare. An overview of the different viral vectors and the threats they counter will be discussed.

Frequent dual initiation of reverse transcription in murine leukemia virus-based vectors containing two primer-binding sites

International Nuclear Information System (INIS)

Voronin, Yegor A.; Pathak, Vinay K.

2003-01-01

Retroviruses package two copies of viral RNA into each virion. Although each RNA contains a primer-binding site for initiation of DNA synthesis, it is unknown whether reverse transcription is initiated on both RNAs. To determine whether a single virion is capable of initiating reverse transcription more than once, we constructed a murine leukemia virus-based vector containing a second primer-binding site (PBS) derived from spleen necrosis virus and inserted the green fluorescent protein gene (GFP) between the two PBSs. Initiation of reverse transcription at either PBS results in a provirus that expresses GFP. However, initiation at both PBSs can result in the deletion of GFP, which can be detected by flow cytometry and Southern blotting analysis. Approximately 22-29% of the proviruses formed deleted the GFP in a single replication cycle, indicating the minimum proportion of virions that initiated reverse transcription on both PBSs. These results show that a significant proportion of MLV-based vectors containing two PBSs have the capacity to initiate reverse transcription more than once

Persistent infection caused by Hobi-like pestivirus.

Science.gov (United States)

Decaro, Nicola; Losurdo, Michele; Lucente, Maria Stella; Sciarretta, Rossana; Mari, Viviana; Larocca, Vittorio; Elia, Gabriella; Cavaliere, Nicola; Martella, Vito; Fasanella, Antonio; Buonavoglia, Canio

2013-04-01

A calf persistently infected by Hobi-like pestivirus was monitored for about 6 months, displaying clinical signs typical of bovine viral diarrhea virus persistent infection and shedding the virus through all body secretions, with maximal titers detected in urine. This report provides new insights into the pathogenesis of the emerging pestivirus.

Stable integration of recombinant adeno-associated virus vector genomes after transduction of murine hematopoietic stem cells.

Science.gov (United States)

Han, Zongchao; Zhong, Li; Maina, Njeri; Hu, Zhongbo; Li, Xiaomiao; Chouthai, Nitin S; Bischof, Daniela; Weigel-Van Aken, Kirsten A; Slayton, William B; Yoder, Mervin C; Srivastava, Arun

2008-03-01

We previously reported that among single-stranded adeno-associated virus (ssAAV) vectors, serotypes 1 through 5, ssAAV1 is the most efficient in transducing murine hematopoietic stem cells (HSCs), but viral second-strand DNA synthesis remains a rate-limiting step. Subsequently, using double-stranded, self-complementary AAV (scAAV) vectors, serotypes 7 through 10, we observed that scAAV7 vectors also transduce murine HSCs efficiently. In the present study, we used scAAV1 and scAAV7 shuttle vectors to transduce HSCs in a murine bone marrow serial transplant model in vivo, which allowed examination of the AAV proviral integration pattern in the mouse genome, as well as recovery and nucleotide sequence analyses of AAV-HSC DNA junction fragments. The proviral genomes were stably integrated, and integration sites were localized to different mouse chromosomes. None of the integration sites was found to be in a transcribed gene, or near a cellular oncogene. None of the animals, monitored for up to 1 year, exhibited pathological abnormalities. Thus, AAV proviral integration-induced risk of oncogenesis was not found in our study, which provides functional confirmation of stable transduction of self-renewing multipotential HSCs by scAAV vectors as well as promise for the use of these vectors in the potential treatment of disorders of the hematopoietic system.

Fungal transmission of plant viruses.

Science.gov (United States)

Campbell, R N

1996-01-01

Thirty soilborne viruses or virus-like agents are transmitted by five species of fungal vectors. Ten polyhedral viruses, of which nine are in the family Tombusviridae, are acquired in the in vitro manner and do not occur within the resting spores of their vectors, Olpidium brassicae and O. bornovanus. Fungal vectors for other viruses in the family should be sought even though tombusviruses are reputed to be soil transmitted without a vector. Eighteen rod-shaped viruses belonging to the furo- and bymovirus groups and to an unclassified group are acquired in the in vivo manner and survive within the resting spores of their vector, O. brassicae, Polymyxa graminis, P. betae, and Spongospora subterranea. The viral coat protein has an essential role in in vitro transmission. With in vivo transmission a site in the coat protein-read through protein (CP-RT) of beet necrotic yellow vein furovirus determines vector transmissibility as does a site in a similar 98-kDa polyprotein of barley mild mosaic bymovirus. The mechanisms by which virions move (or are moved) into and out of the protoplasm of zoospores or of thalli needs study.

Hazard Characterization of Modified Vaccinia Virus Ankara Vector: What Are the Knowledge Gaps?

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Malachy I. Okeke

2017-10-01

Full Text Available Modified vaccinia virus Ankara (MVA is the vector of choice for human and veterinary applications due to its strong safety profile and immunogenicity in vivo. The use of MVA and MVA-vectored vaccines against human and animal diseases must comply with regulatory requirements as they pertain to environmental risk assessment, particularly the characterization of potential adverse effects to humans, animals and the environment. MVA and recombinant MVA are widely believed to pose low or negligible risk to ecosystem health. However, key aspects of MVA biology require further research in order to provide data needed to evaluate the potential risks that may occur due to the use of MVA and MVA-vectored vaccines. The purpose of this paper is to identify knowledge gaps in the biology of MVA and recombinant MVA that are of relevance to its hazard characterization and discuss ongoing and future experiments aimed at providing data necessary to fill in the knowledge gaps. In addition, we presented arguments for the inclusion of uncertainty analysis and experimental investigation of verifiable worst-case scenarios in the environmental risk assessment of MVA and recombinant MVA. These will contribute to improved risk assessment of MVA and recombinant MVA vaccines.

Development and applications of VSV vectors based on cell tropism

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Hideki eTani

2012-01-01

Full Text Available Viral vectors have been available in various fields such as medical and biological research or gene therapy applications. Targeting vectors pseudotyped with distinct viral envelope proteins that influence cell tropism and transfection efficiency is a useful tool not only for examining entry mechanisms or cell tropisms but also for vaccine vector development. Vesicular stomatitis virus (VSV is an excellent candidate for development as a pseudotype vector. A recombinant VSV lacking its own envelope (G gene has been used to produce a pseudotype or recombinant VSV possessing the envelope proteins of heterologous viruses. These viruses possess a reporter gene instead of a VSV G gene in their genome, and therefore it is easy to evaluate their infectivity in the study of viral entry, including identification of viral receptors. Furthermore, advantage can be taken of a property of the pseudotype VSV, which is competence for single-round infection, in handling many different viruses that are either difficult to amplify in cultured cells or animals or that require specialized containment facilities. Here we describe procedures for producing pseudotype or recombinant VSVs and a few of the more prominent examples from among envelope viruses, such as hepatitis C virus, Japanese encephalitis virus, baculovirus, and hemorrhagic fever viruses.

Vector Competence of Aedes aegypti and Aedes polynesiensis Populations from French Polynesia for Chikungunya Virus.

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Vaea Richard

2016-05-01

Full Text Available From October 2014 to March 2015, French Polynesia experienced for the first time a chikungunya outbreak. Two Aedes mosquitoes may have contributed to chikungunya virus (CHIKV transmission in French Polynesia: the worldwide distributed Ae. aegypti and the Polynesian islands-endemic Ae. polynesiensis mosquito.To investigate the vector competence of French Polynesian populations of Ae. aegypti and Ae. polynesiensis for CHIKV, mosquitoes were exposed per os at viral titers of 7 logs tissue culture infectious dose 50%. At 2, 6, 9, 14 and 21 days post-infection (dpi, saliva was collected from each mosquito and inoculated onto C6/36 mosquito cells to check for the presence of CHIKV infectious particles. Legs and body (thorax and abdomen of each mosquito were also collected at the different dpi and submitted separately to viral RNA extraction and CHIKV real-time RT-PCR.CHIKV infection rate, dissemination and transmission efficiencies ranged from 7-90%, 18-78% and 5-53% respectively for Ae. aegypti and from 39-41%, 3-17% and 0-14% respectively for Ae. polynesiensis, depending on the dpi. Infectious saliva was found as early as 2 dpi for Ae. aegypti and from 6 dpi for Ae. polynesiensis. Our laboratory results confirm that the French Polynesian population of Ae. aegypti is highly competent for CHIKV and they provide clear evidence for Ae. polynesiensis to act as an efficient CHIKV vector.As supported by our findings, the presence of two CHIKV competent vectors in French Polynesia certainly contributed to enabling this virus to quickly disseminate from the urban/peri-urban areas colonized by Ae. aegypti to the most remote atolls where Ae. polynesiensis is predominating. Ae. polynesiensis was probably involved in the recent chikungunya outbreaks in Samoa and the Cook Islands. Moreover, this vector may contribute to the risk for CHIKV to emerge in other Polynesian islands like Fiji, and more particularly Wallis where there is no Ae. aegypti.

Vector Contact Rates on Eastern Bluebird Nestlings Do Not Indicate West Nile Virus Transmission in Henrico County, Virginia, USA

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Kevin A. Caillouët

2013-11-01

Full Text Available Sensitive indicators of spatial and temporal variation in vector-host contact rates are critical to understanding the transmission and eventual prevention of arboviruses such as West Nile virus (WNV. Monitoring vector contact rates on particularly susceptible and perhaps more exposed avian nestlings may provide an advanced indication of local WNV amplification. To test this hypothesis we monitored WNV infection and vector contact rates among nestlings occupying nest boxes (primarily Eastern bluebirds; Sialia sialis, Turdidae across Henrico County, Virginia, USA, from May to August 2012. Observed host-seeking rates were temporally variable and associated with absolute vector and host abundances. Despite substantial effort to monitor WNV among nestlings and mosquitoes, we did not detect the presence of WNV in these populations. Generally low vector-nestling host contact rates combined with the negative WNV infection data suggest that monitoring transmission parameters among nestling Eastern bluebirds in Henrico County, Virginia, USA may not be a sensitive indicator of WNV activity.

The Dengue Virus Mosquito Vector Aedes aegypti at High Elevation in México

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Lozano-Fuentes, Saul; Hayden, Mary H.; Welsh-Rodriguez, Carlos; Ochoa-Martinez, Carolina; Tapia-Santos, Berenice; Kobylinski, Kevin C.; Uejio, Christopher K.; Zielinski-Gutierrez, Emily; Monache, Luca Delle; Monaghan, Andrew J.; Steinhoff, Daniel F.; Eisen, Lars

2012-01-01

México has cities (e.g., México City and Puebla City) located at elevations > 2,000 m and above the elevation ceiling below which local climates allow the dengue virus mosquito vector Aedes aegypti to proliferate. Climate warming could raise this ceiling and place high-elevation cities at risk for dengue virus transmission. To assess the elevation ceiling for Ae. aegypti and determine the potential for using weather/climate parameters to predict mosquito abundance, we surveyed 12 communities along an elevation/climate gradient from Veracruz City (sea level) to Puebla City (∼2,100 m). Ae. aegypti was commonly encountered up to 1,700 m and present but rare from 1,700 to 2,130 m. This finding extends the known elevation range in México by > 300 m. Mosquito abundance was correlated with weather parameters, including temperature indices. Potential larval development sites were abundant in Puebla City and other high-elevation communities, suggesting that Ae. aegypti could proliferate should the climate become warmer. PMID:22987656

Population genetics of two key mosquito vectors of Rift Valley Fever virus reveals new insights into the changing disease outbreak patterns in Kenya.

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David P Tchouassi

2014-12-01

Full Text Available Rift Valley fever (RVF outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi and newly-associated (Ae. ochraceus vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification.

Population Genetics of Two Key Mosquito Vectors of Rift Valley Fever Virus Reveals New Insights into the Changing Disease Outbreak Patterns in Kenya

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Tchouassi, David P.; Bastos, Armanda D. S.; Sole, Catherine L.; Diallo, Mawlouth; Lutomiah, Joel; Mutisya, James; Mulwa, Francis; Borgemeister, Christian; Sang, Rosemary; Torto, Baldwyn

2014-01-01

Rift Valley fever (RVF) outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi) and newly-associated (Ae. ochraceus) vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification. PMID:25474018

West Nile virus in livestock and wildlife

Science.gov (United States)

McLean, R.G.; Ubico, S.R.; Bourne, D.; Komar, N.

2002-01-01

the emergence of one or more new strains of WN virus. Virus isolated in New York in 1999 was found to be identical to that from Israel. It was alarming for WN virus to so easily invade the United States and surprising that it became established so quickly in the temperature climate of New York. Its persistence and rapid expansion in the United States leave a number of unanswered questions. New disease characteristics and patterns have occurred and more are evolving as WN virus further invades the western hemisphere. Additional animal research is needed to answer these questions. Some of the research needs include bird migration as a mechanism of virus dispersal, vector and vertebrate host relationships, virus persistence mechanisms, laboratory diagnosis, viral pathogenesis, risk factor studies, vaccine development, and WN virus impact on wildlife (CDC 2001a). Determination of the primary reservoir host species that are involved in the epidemiology of WN virus and the suitable sentinel species for active surveillance are also important research areas.

Herbivore arthropods benefit from vectoring plant viruses

NARCIS (Netherlands)

Belliure, B.; Janssen, A.; Maris, P.C.; Peters, D.; Sabelis, M.W.

2005-01-01

Plants infected with pathogens often attract the pathogens' vectors, but it is not clear if this is advantageous to the vectors. We therefore quantified the direct and indirect (through the host plant) effects of a pathogen on its vector. A positive direct effect of the plant-pathogenic Tomato

Mouse Mammary Tumor Virus Promoter-Containing Retroviral Promoter Conversion Vectors for Gene-Directed Enzyme Prodrug Therapy are Functional in Vitro and in Vivo

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Reinhard Klein

2008-01-01

Full Text Available Gene directed-enzyme prodrug therapy (GDEPT is an approach for sensitization of tumor cells to an enzymatically activated, otherwise nontoxic, prodrug. Cytochrome P450 2B1 (CYP2B1 metabolizes the prodrugs cyclophosphamide (CPA and ifosfamide (IFA to produce the cytotoxic substances phosphoramide mustard and isophosphoramide mustard as well as the byproduct acrolein. We have constructed a retroviral promoter conversion (ProCon vector for breast cancer GDEPT. The vector allows expression of CYP2B1 from the mouse mammary tumor virus (MMTV promoter known to be active in the mammary glands of transgenic animals. It is anticipated to be used for the generation of encapsulated viral vector producing cells which, when placed inside or close to a tumor, will act as suppliers of the therapeutic CYP2B1 protein as well as of the therapeutic vector itself. The generated vector was effectively packaged by virus producing cells and allowed the production of high levels of enzymatically active CYP2B1 in infected cells which sensitized them to killing upon treatment with both IFA and CPA. Determination of the respective IC50 values demonstrated that the effective IFA dose was reduced by sixteen folds. Infection efficiencies in vivo were determined using a reporter gene-bearing vector in a mammary cancer cell-derived xenograft tumor mouse model.

Phase 2 clinical trial of a recombinant adeno-associated viral vector expressing α1-antitrypsin: interim results.

LENUS (Irish Health Repository)

Flotte, Terence R

2011-10-01

Recombinant adeno-associated virus (rAAV) vectors offer promise for the gene therapy of α(1)-antitrypsin (AAT) deficiency. In our prior trial, an rAAV vector expressing human AAT (rAAV1-CB-hAAT) provided sustained, vector-derived AAT expression for >1 year. In the current phase 2 clinical trial, this same vector, produced by a herpes simplex virus complementation method, was administered to nine AAT-deficient individuals by intramuscular injection at doses of 6.0×10(11), 1.9×10(12), and 6.0×10(12) vector genomes\\/kg (n=3 subjects\\/dose). Vector-derived expression of normal (M-type) AAT in serum was dose dependent, peaked on day 30, and persisted for at least 90 days. Vector administration was well tolerated, with only mild injection site reactions and no serious adverse events. Serum creatine kinase was transiently elevated on day 30 in five of six subjects in the two higher dose groups and normalized by day 45. As expected, all subjects developed anti-AAV antibodies and interferon-γ enzyme-linked immunospot responses to AAV peptides, and no subjects developed antibodies to AAT. One subject in the mid-dose group developed T cell responses to a single AAT peptide unassociated with any clinical effects. Muscle biopsies obtained on day 90 showed strong immunostaining for AAT and moderate to marked inflammatory cell infiltrates composed primarily of CD3-reactive T lymphocytes that were primarily of the CD8(+) subtype. These results support the feasibility and safety of AAV gene therapy for AAT deficiency, and indicate that serum levels of vector-derived normal human AAT >20 μg\\/ml can be achieved. However, further improvements in the design or delivery of rAAV-AAT vectors will be required to achieve therapeutic target serum AAT concentrations.

Hepatorenal correction in murine glycogen storage disease type I with a double-stranded adeno-associated virus vector.

LENUS (Irish Health Repository)

Luo, Xiaoyan

2011-11-01

Glycogen storage disease type Ia (GSD-Ia) is caused by the deficiency of glucose-6-phosphatase (G6Pase). Long-term complications of GSD-Ia include life-threatening hypoglycemia and proteinuria progressing to renal failure. A double-stranded (ds) adeno-associated virus serotype 2 (AAV2) vector encoding human G6Pase was pseudotyped with four serotypes, AAV2, AAV7, AAV8, and AAV9, and we evaluated efficacy in 12-day-old G6pase (-\\/-) mice. Hypoglycemia during fasting (plasma glucose <100 mg\\/dl) was prevented for >6 months by the dsAAV2\\/7, dsAAV2\\/8, and dsAAV2\\/9 vectors. Prolonged fasting for 8 hours revealed normalization of blood glucose following dsAAV2\\/9 vector administration at the higher dose. The glycogen content of kidney was reduced by >65% with both the dsAAV2\\/7 and dsAAV2\\/9 vectors, and renal glycogen content was stably reduced between 7 and 12 months of age for the dsAAV2\\/9 vector-treated mice. Every vector-treated group had significantly reduced glycogen content in the liver, in comparison with untreated G6pase (-\\/-) mice. G6Pase was expressed in many renal epithelial cells of with the dsAAV2\\/9 vector for up to 12 months. Albuminuria and renal fibrosis were reduced by the dsAAV2\\/9 vector. Hepatorenal correction in G6pase (-\\/-) mice demonstrates the potential of AAV vectors for the correction of inherited diseases of metabolism.

Need for a safe vaccine against respiratory syncytial virus infection

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Joo-Young Kim

2012-09-01

Full Text Available Human respiratory syncytial virus (HRSV is a major cause of severe respiratory tract illnesses in infants and young children worldwide. Despite its importance as a respiratory pathogen, there is currently no licensed vaccine for HRSV. Following failure of the initial trial of formalin-inactivated virus particle vaccine, continuous efforts have been made for the development of safe and efficacious vaccines against HRSV. However, several obstacles persist that delay the development of HRSV vaccine, such as the immature immune system of newborn infants and the possible Th2-biased immune responses leading to subsequent vaccine-enhanced diseases. Many HRSV vaccine strategies are currently being developed and evaluated, including live-attenuated viruses, subunit-based, and vector-based candidates. In this review, the current HRSV vaccines are overviewed and the safety issues regarding asthma and vaccine-induced pathology are discussed.

Inflammation and Immune Response of Intra-Articular Serotype 2 Adeno-Associated Virus or Adenovirus Vectors in a Large Animal Model

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Akikazu Ishihara

2012-01-01

Full Text Available Intra-articular gene therapy has potential for the treatment of osteoarthritis and rheumatoid arthritis. To quantify in vitro relative gene transduction, equine chondrocytes and synovial cells were treated with adenovirus vectors (Ad, serotype 2 adeno-associated virus vectors (rAAV2, or self-complementary (sc AAV2 vectors carrying green fluorescent protein (GFP. Using 6 horses, bilateral metacarpophalangeal joints were injected with Ad, rAAV2, or scAAV2 vectors carrying GFP genes to assess the in vivo joint inflammation and neutralizing antibody (NAb titer in serum and joint fluid. In vitro, the greater transduction efficiency and sustained gene expression were achieved by scAAV2 compared to rAAV2 in equine chondrocytes and synovial cells. In vivo, AAV2 demonstrated less joint inflammation than Ad, but similar NAb titer. The scAAV2 vectors can induce superior gene transduction than rAAV2 in articular cells, and both rAAV2 and scAAV2 vectors were showed to be safer for intra-articular use than Ad vectors.

Caligus rogercresseyi: posible vector en la transmisión horizontal del virus de la anemia infecciosa del salmón (ISAv

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Karin Oelckers

2015-05-01

Full Text Available Chile el año 2007 se convirtió en el segundo país productor de salmónidos a nivel mundial. Al año siguiente la industria salmonera nacional comenzó a experimentar una severa crisis sanitaria producida por el virus causante de la anemia infecciosa del salmón. Este virus se presentó por primera vez en Noruega (1984, luego en Canadá, Escocia, Islas Faroe, Estados Unidos y Chile (2007. La anemia infecciosa del salmón (ISA, es una enfermedad altamente contagiosa entre los peces, producida por un virus de la familia Orthomyxoviridae. La especie más vulnerable a este virus es el salmón del Atlántico (Salmo salar. La plaga parasitaria producida por el piojo de mar, Caligus rogercresseyi, copépodo ectoparásito, ha ido en aumento lo que favorece el contagio de enfermedades bacterianas y virales. De todas las especies cultivadas en Chile, el salmón del Atlántico, S. salar es una de las especies más susceptibles de ser infestadas por C. rogercresseyi. Durante el 2006, la industria presentó un aumento significativo en las tasas de infestación por Caligus; luego en el 2007, aparecieron brotes del virus ISA. En Noruega, se ha demostrado que el piojo de mar, Lepeophtherius salmonis puede tener un rol como vector en la transmisión del virus ISA, por lo que el objetivo de este trabajo fue determinar si C. rogercresseyi es un vector de transmisión del virus ISA en el salmón del Atlántico, cultivado en el sur de Chile.

Relevance of Assembly-Activating Protein for Adeno-associated Virus Vector Production and Capsid Protein Stability in Mammalian and Insect Cells.

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Grosse, Stefanie; Penaud-Budloo, Magalie; Herrmann, Anne-Kathrin; Börner, Kathleen; Fakhiri, Julia; Laketa, Vibor; Krämer, Chiara; Wiedtke, Ellen; Gunkel, Manuel; Ménard, Lucie; Ayuso, Eduard; Grimm, Dirk

2017-10-15

The discovery that adeno-associated virus 2 (AAV2) encodes an eighth protein, called assembly-activating protein (AAP), transformed our understanding of wild-type AAV biology. Concurrently, it raised questions about the role of AAP during production of recombinant vectors based on natural or molecularly engineered AAV capsids. Here, we show that AAP is indeed essential for generation of functional recombinant AAV2 vectors in both mammalian and insect cell-based vector production systems. Surprisingly, we observed that AAV2 capsid proteins VP1 to -3 are unstable in the absence of AAP2, likely due to rapid proteasomal degradation. Inhibition of the proteasome led to an increase of intracellular VP1 to -3 but neither triggered assembly of functional capsids nor promoted nuclear localization of the capsid proteins. Together, this underscores the crucial and unique role of AAP in the AAV life cycle, where it rapidly chaperones capsid assembly, thus preventing degradation of free capsid proteins. An expanded analysis comprising nine alternative AAV serotypes (1, 3 to 9, and rh10) showed that vector production always depends on the presence of AAP, with the exceptions of AAV4 and AAV5, which exhibited AAP-independent, albeit low-level, particle assembly. Interestingly, AAPs from all 10 serotypes could cross-complement AAP-depleted helper plasmids during vector production, despite there being distinct intracellular AAP localization patterns. These were most pronounced for AAP4 and AAP5, congruent with their inability to rescue an AAV2/AAP2 knockout. We conclude that AAP is key for assembly of genuine capsids from at least 10 different AAV serotypes, which has implications for vectors derived from wild-type or synthetic AAV capsids. IMPORTANCE Assembly of adeno-associated virus 2 (AAV2) is regulated by the assembly-activating protein (AAP), whose open reading frame overlaps with that of the viral capsid proteins. As the majority of evidence was obtained using virus

Polydnaviruses of Parasitic Wasps: Domestication of Viruses To Act as Gene Delivery Vectors

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Michael R. Strand

2012-01-01

Full Text Available Symbiosis is a common phenomenon in which associated organisms can cooperate in ways that increase their ability to survive, reproduce, or utilize hostile environments. Here, we discuss polydnavirus symbionts of parasitic wasps. These viruses are novel in two ways: (1 they have become non-autonomous domesticated entities that cannot replicate outside of wasps; and (2 they function as a delivery vector of genes that ensure successful parasitism of host insects that wasps parasitize. In this review we discuss how these novelties may have arisen, which genes are potentially involved, and what the consequences have been for genome evolution.

Identification of potential vectors of and detection of antibodies against Rift Valley fever virus in livestock during interepizootic periods.

Science.gov (United States)

Rostal, Melinda K; Evans, Alina L; Sang, Rosemary; Gikundi, Solomon; Wakhule, Lilian; Munyua, Peninah; Macharia, Joseph; Feikin, Daniel R; Breiman, Robert F; Njenga, M Kariuki

2010-05-01

To evaluate the prevalence of Rift Valley fever virus (RVFV) antibodies in livestock and presence of competent mosquito vectors of RVFV during an interepizootic period (IEP) in Kenya. 208 sheep and 84 goats ranging in age from 4 months to 15 years, from 2 breeding herds. Blood specimens were collected from the sheep and goats during the 1999-2006 IEP in Rift Valley Province, and serum was harvested. Serum specimens were tested for IgG and IgM antibodies against RVFV by use of an ELISA. In addition, 7,134 mosquitoes were trapped in Naivasha, Nairobi, and Northeastern Province, and speciation was performed. No animals were seropositive for IgM against RVFV. Of the animals born after the 1997-1998 epizootic, 18% (34/188) of sheep were seropositive for IgG against RVFV, compared with 3% (2/75) of goats. Seventy percent (8,144/11,678) of the mosquitoes collected were of the Culex subgenera; 18% (2,102/11,678) were Aedes spp. Detection of IgG in the sera of sheep and goats born after the 1997-1998 epizootic and before the 2006 epizootic indicated that virus activity existed during the IEP. Detection of Aedes mosquitoes, which are competent vectors of RVFV, suggested that a cryptic vector-to-vertebrate cycle may exist during IEPs.

Reverse genetics of measles virus and resulting multivalent recombinant vaccines: applications of recombinant measles viruses.

Science.gov (United States)

Billeter, M A; Naim, H Y; Udem, S A

2009-01-01

An overview is given on the development of technologies to allow reverse genetics of RNA viruses, i.e., the rescue of viruses from cDNA, with emphasis on nonsegmented negative-strand RNA viruses (Mononegavirales), as exemplified for measles virus (MV). Primarily, these technologies allowed site-directed mutagenesis, enabling important insights into a variety of aspects of the biology of these viruses. Concomitantly, foreign coding sequences were inserted to (a) allow localization of virus replication in vivo through marker gene expression, (b) develop candidate multivalent vaccines against measles and other pathogens, and (c) create candidate oncolytic viruses. The vector use of these viruses was experimentally encouraged by the pronounced genetic stability of the recombinants unexpected for RNA viruses, and by the high load of insertable genetic material, in excess of 6 kb. The known assets, such as the small genome size of the vector in comparison to DNA viruses proposed as vectors, the extensive clinical experience of attenuated MV as vaccine with a proven record of high safety and efficacy, and the low production cost per vaccination dose are thus favorably complemented.

Meta-analyses of the proportion of Japanese encephalitis virus infection in vectors and vertebrate hosts.

Science.gov (United States)

Oliveira, Ana R S; Cohnstaedt, Lee W; Strathe, Erin; Hernández, Luciana Etcheverry; McVey, D Scott; Piaggio, José; Cernicchiaro, Natalia

2017-09-07

Japanese encephalitis (JE) is a zoonosis in Southeast Asia vectored by mosquitoes infected with the Japanese encephalitis virus (JEV). Japanese encephalitis is considered an emerging exotic infectious disease with potential for introduction in currently JEV-free countries. Pigs and ardeid birds are reservoir hosts and play a major role on the transmission dynamics of the disease. The objective of the study was to quantitatively summarize the proportion of JEV infection in vectors and vertebrate hosts from data pertaining to observational studies obtained in a systematic review of the literature on vector and host competence for JEV, using meta-analyses. Data gathered in this study pertained to three outcomes: proportion of JEV infection in vectors, proportion of JEV infection in vertebrate hosts, and minimum infection rate (MIR) in vectors. Random-effects subgroup meta-analysis models were fitted by species (mosquito or vertebrate host species) to estimate pooled summary measures, as well as to compute the variance between studies. Meta-regression models were fitted to assess the association between different predictors and the outcomes of interest and to identify sources of heterogeneity among studies. Predictors included in all models were mosquito/vertebrate host species, diagnostic methods, mosquito capture methods, season, country/region, age category, and number of mosquitos per pool. Mosquito species, diagnostic method, country, and capture method represented important sources of heterogeneity associated with the proportion of JEV infection; host species and region were considered sources of heterogeneity associated with the proportion of JEV infection in hosts; and diagnostic and mosquito capture methods were deemed important contributors of heterogeneity for the MIR outcome. Our findings provide reference pooled summary estimates of vector competence for JEV for some mosquito species, as well as of sources of variability for these outcomes. Moreover, this

Integration of adeno-associated virus vectors in CD34+ human hematopoietic progenitor cells after transduction.

Science.gov (United States)

Fisher-Adams, G; Wong, K K; Podsakoff, G; Forman, S J; Chatterjee, S

1996-07-15

Gene transfer vectors based on adeno-associated virus (AAV) appear promising because of their high transduction frequencies regardless of cell cycle status and ability to integrate into chromosomal DNA. We tested AAV-mediated gene transfer into a panel of human bone marrow or umbilical cord-derived CD34+ hematopoietic progenitor cells, using vectors encoding several transgenes under the control of viral and cellular promoters. Gene transfer was evaluated by (1) chromosomal integration of vector sequences and (2) analysis of transgene expression. Southern hybridization and fluorescence in situ hybridization analysis of transduced CD34 genomic DNA showed the presence of integrated vector sequences in chromosomal DNA in a portion of transduced cells and showed that integrated vector sequences were replicated along with cellular DNA during mitosis. Transgene expression in transduced CD34 cells in suspension cultures and in myeloid colonies differentiating in vitro from transduced CD34 cells approximated that predicted by the multiplicity of transduction. This was true in CD34 cells from different donors, regardless of the transgene or selective pressure. Comparisons of CD34 cell transduction either before or after cytokine stimulation showed similar gene transfer frequencies. Our findings suggest that AAV transduction of CD34+ hematopoietic progenitor cells is efficient, can lead to stable integration in a population of transduced cells, and may therefore provide the basis for safe and efficient ex vivo gene therapy of the hematopoietic system.

Effects of time after infection, mosquito genotype, and infectious viral dose on the dynamics of Culex tarsalis vector competence for western equine encephalomyelitis virus.

Science.gov (United States)

Mahmood, Farida; Chiles, Robert E; Fang, Ying; Green, Emily N; Reisen, William K

2006-06-01

The vector competence of Culex tarsalis Coquillett for the BFS 1703 strain of western equine encephalomyelitis virus (WEEV) changed significantly as a function of time after infection, mosquito genotype, and infectious virus dose. After ingesting a high virus dose (5 log10 plaque-forming units [PFU]/0.1 ml), female of the susceptible high virus producer (HVP) strain rapidly amplified the virus, developed a disseminated infection, and efficiently transmitted WEEV by 4 days postinfection (dpi). The quantity of virus expectorated peaked at 4 dpi (mean 3.4 log10 PFU), and the percentage of females transmitting per os peaked at 7 dpi (80%); both measures of transmission subsequently decreased to low levels throughout the remainder of infected life. HVP females imbibing a low virus dose (3 log10 PFU/0.1 ml) were infected less frequently and took longer to amplify virus to levels recorded for the high virus dose group and did not transmit virus efficiently, thereby indicating midgut infection and escape barriers were dose and time dependent. These data emphasized the importance of elevated avian viremias in Cx. tarsalis vector competence. Females from the WEEV-resistant (WR) strain and two wild-type strains from Kern and Riverside counties were significantly less susceptible to infection at both high and low doses than was the HVP strain. Overall, females with a high virus titer more frequently had a disseminated infection, but there did not seem to be a distinct threshold demarcating this relationship. In marked contrast, all infected females transmitting virus had body titers >4.3 log10 PFU, and most had titers >4.8 log10 PFU. These data indicated that not all females with a disseminated infection transmitted virus because of the presence of one or more salivary gland barriers.

Synchrony of sylvatic dengue isolations: a multi-host, multi-vector SIR model of dengue virus transmission in Senegal.

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Benjamin M Althouse

Full Text Available Isolations of sylvatic dengue-2 virus from mosquitoes, humans and non-human primates in Senegal show synchronized multi-annual dynamics over the past 50 years. Host demography has been shown to directly affect the period between epidemics in other pathogen systems, therefore, one might expect unsynchronized multi-annual cycles occurring in hosts with dramatically different birth rates and life spans. However, in Senegal, we observe a single synchronized eight-year cycle across all vector species, suggesting synchronized dynamics in all vertebrate hosts. In the current study, we aim to explore two specific hypotheses: 1 primates with different demographics will experience outbreaks of dengue at different periodicities when observed as isolated systems, and that coupling of these subsystems through mosquito biting will act to synchronize incidence; and 2 the eight-year periodicity of isolations observed across multiple primate species is the result of long-term cycling in population immunity in the host populations. To test these hypotheses, we develop a multi-host, multi-vector Susceptible, Infected, Removed (SIR model to explore the effects of coupling multiple host-vector systems of dengue virus transmission through cross-species biting rates. We find that under small amounts of coupling, incidence in the host species synchronize. Long-period multi-annual dynamics are observed only when prevalence in troughs reaches vanishingly small levels (< 10(-10, suggesting that these dynamics are inconsistent with sustained transmission in this setting, but are consistent with local dengue virus extinctions followed by reintroductions. Inclusion of a constant introduction of infectious individuals into the system causes the multi-annual periods to shrink, while the effects of coupling remain the same. Inclusion of a stochastic rate of introduction allows for multi-annual periods at a cost of reduced synchrony. Thus, we conclude that the eight-year period

Candidate Vectors and Rodent Hosts of Venezuelan Equine Encephalitis Virus, Chiapas, 2006–2007

Science.gov (United States)

Deardorff, Eleanor R.; Estrada-Franco, Jose G.; Freier, Jerome E.; Navarro-Lopez, Roberto; Da Rosa, Amelia Travassos; Tesh, Robert B.; Weaver, Scott C.

2011-01-01

Enzootic Venezuelan equine encephalitis virus (VEEV) has been known to occur in Mexico since the 1960s. The first natural equine epizootic was recognized in Chiapas in 1993 and since then, numerous studies have characterized the etiologic strains, including reverse genetic studies that incriminated a specific mutation that enhanced infection of epizootic mosquito vectors. The aim of this study was to determine the mosquito and rodent species involved in enzootic maintenance of subtype IE VEEV in coastal Chiapas. A longitudinal study was conducted over a year to discern which species and habitats could be associated with VEEV circulation. Antibody was rarely detected in mammals and virus was not isolated from mosquitoes. Additionally, Culex (Melanoconion) taeniopus populations were found to be spatially related to high levels of human and bovine seroprevalence. These mosquito populations were concentrated in areas that appear to represent foci of stable, enzootic VEEV circulation. PMID:22144461

Studies towards the potential of poliovirus as a vector for the expression of HPV 16 virus-like-particles.

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van Kuppeveld, Frank J M; de Jong, Arjan; Dijkman, Henri B P M; Andino, Raul; Melchers, Willem J G

2002-11-15

Development of human cervical carcinomas is associated with infection by certain human papillomavirus (HPV) types. Thus, protection against HPV infection through vaccination may prevent development of cervical cancer. The purpose of this study was to investigate the possibility of using a poliovirus recombinant vector to induce immunity against HPV. A poliovirus recombinant was constructed which contained the complete coding sequence of the HPV 16 major capsid protein L1, between the P1 and P2 region of the poliovirus polyprotein. A replication-competent virus was obtained after transfection of the recombinant RNA into tissue culture cells. Electron microscopically examination of cells infected with the poliovirus-HPV L1 recombinant indicated that HPV 16 L1 self-assembles into virus-like particles. To investigate the immunological response in vivo, susceptible transgenic mice carrying the poliovirus receptor were infected with the recombinant poliovirus. In all mice a modest but consistent immune response against HPV 16 was observed. Based on these results, the potential for picornavirus-derived vectors in vaccine development against HPV infection is discussed.

Inflation persistence and flexible prices

OpenAIRE

Robert Dittmar; William T. Gavin; Finn E. Kydland

2004-01-01

If the central bank follows an interest rate rule, then inflation is likely to be persistence, even when prices are fully flexible. Any shock, whether persistent or not, may lead to inflation persistence. In equilibrium, the dynamics of inflation are determined by the evolution of the spread between the real interest rate and the central bank’s target. Inflation persistence in U.S. data can be characterized by a vector autocorrelation function relating inflation and deviations of output from ...

Implementation of immunohistochemistry on frozen ear notch tissue samples in diagnosis of bovine viral diarrhea virus in persistently infected cattle

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Bedeković Tomislav

2011-12-01

Full Text Available Abstract Background Bovine viral diarrhea is a contagious disease of domestic and wild ruminants and one of the most economically important diseases in cattle. Bovine viral diarrhea virus belongs to the genus Pestivirus, within the family Flaviviridae. The identification and elimination of the persistently infected animals from herds is the initial step in the control and eradication programs. It is therefore necessary to have reliable methods for diagnosis of bovine viral diarrhea virus. One of those methods is immunohistochemistry. Immunohistochemistry on formalin fixed, paraffin embedded tissue is a routine technique in diagnosis of persistently infected cattle from ear notch tissue samples. However, such technique is inappropriate due to complicated tissue fixation process and it requires more days for preparation. On the contrary, immunohistochemistry on frozen tissue was usually applied on organs from dead animals. In this paper, for the first time, the imunohistochemistry on frozen ear notch tissue samples was described. Findings Seventeen ear notch tissue samples were obtained during the period 2008-2009 from persistently infected cattle. Samples were fixed in liquid nitrogen and stored on -20°C until testing. Ear notch tissue samples from all persistently infected cattle showed positive results with good section quality and possibility to determinate type of infected cells. Conclusions Although the number of samples was limited, this study indicated that immunohistochemistry on formalin fixed paraffin embedded tissue can be successfully replaced with immunohistochemistry on frozen ear notch tissue samples in diagnosis of persistently infected cattle.

Rotavirus Virus-Like Particles as Surrogates in Environmental Persistence and Inactivation Studies

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Caballero, Santiago; Abad, F. Xavier; Loisy, Fabienne; Le Guyader, Françoise S.; Cohen, Jean; Pintó, Rosa M.; Bosch, Albert

2004-01-01

Virus-like particles (VLPs) with the full-length VP2 and VP6 rotavirus capsid proteins, produced in the baculovirus expression system, have been evaluated as surrogates of human rotavirus in different environmental scenarios. Green fluorescent protein-labeled VLPs (GFP-VLPs) and particles enclosing a heterologous RNA (pseudoviruses), whose stability may be monitored by flow cytometry and antigen capture reverse transcription-PCR, respectively, were used. After 1 month in seawater at 20°C, no significant differences were observed between the behaviors of GFP-VLPs and of infectious rotavirus, whereas pseudovirus particles showed a higher decay rate. In the presence of 1 mg of free chlorine (FC)/liter both tracers persisted longer in freshwater at 20°C than infectious viruses, whereas in the presence of 0.2 mg of FC/liter no differences were observed between tracers and infectious rotavirus at short contact times. However, from 30 min of contact with FC onward, the decay of infectious rotavirus was higher than that of recombinant particles. The predicted Ct value for a 90% reduction of GFP-VLPs or pseudoviruses induces a 99.99% inactivation of infectious rotavirus. Both tracers were more resistant to UV light irradiation than infectious rotavirus in fresh and marine water. The effect of UV exposure was more pronounced on pseudovirus than in GFP-VLPs. In all types of water, the UV dose to induce a 90% reduction of pseudovirus ensures a 99.99% inactivation of infectious rotavirus. Recombinant virus surrogates open new possibilities for the systematic validation of virus removal practices in actual field situations where pathogenic agents cannot be introduced. PMID:15240262

[Construction of RNA-containing virus-like nanoparticles expression vector with cysteine residues on surface and fluorescent decoration].

Science.gov (United States)

Cheng, Yang-Jian; Liang, Ji-Xuan; Li, Qing-Ge

2005-08-01

Site-directed mutagenesis was performed at the codon 15 of the MS2 bacteriophage coat protein gene,which had been cloned to the virus-like particles expression vector containing non-self RNA fragment. The produced expression vector,termed pARSC, was transformed to E. coli DH5alpha. The positive clones were selected and proliferated. The harvested cells were treated with sonication and the supernatant was then subjected to linear sucrose density gradients centrifugation (15% to 60%) at 32000 r/min for 4 h at 4 degrees C. The virus-like particles, VLP-Cy, were collected at 35% sucrose density. The particles were examined by transmission electron microscopy and the spherical viral particles of approximately 27 nm in diameter were found. The thiolated VLP-Cy was then chemically modified with fluorescein -5'-maleimide. The covalent fluorescent labeling was confirmed by absorption analysis, SDS-PAGE and MALDI-TOF mass spectroscopy. This is the first report of preparation of RNA-containing natural fluorescent nanoparticles. The study highlight the versatility of MS2 bacteriophage capsids as building blocks for functional nanomaterials construction for a variety of application purposes.

Vector borne diseases

OpenAIRE

Melillo Fenech, Tanya

2010-01-01

A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent. The transmission depends upon the attributes and requirements of at least three different Iiving organisms : the pathologic agent which is either a virus, protozoa, bacteria or helminth (worm); the vector, which is commonly an arthropod such as ticks or mosquitoes; and the human host.

Augmentation of alphavirus vector-induced human papilloma virus-specific immune and anti-tumour responses by co-expression of interleukin-12

NARCIS (Netherlands)

Riezebos-Brilman, Annelies; Regts, Joke; Chen, Margaret; Wilschut, Jan; Daemen, Toos

2009-01-01

To enhance the efficacy of a therapeutic immunisition strategy against human papillomavirus-induced cervical cancer we evaluated the adjuvant effect of interleukin-12 (IL12) expressed by a Semliki Forest virus vector (SFV) in mice. Depending on the dose and schedule. SFV-IL12 Stimulated

Recombinant Newcastle disease virus (NDV) with inserted gene coding for GM-CSF as a new vector for cancer immunogene therapy

NARCIS (Netherlands)

Janke, M.; Peeters, B.P.H.; Leeuw, de O.S.; Moormann, R.J.M.; Arnold, A.; Fournier, P.; Schirrmacher, V.

2007-01-01

This is the first report describing recombinant (rec) Newcastle disease virus (NDV) as vector for gene therapy of cancer. The gene encoding granulocyte/macrophage colony-stimulating factor (GM-CSF) was inserted as an additional transcription unit at two different positions into the NDV genome. The

Ebola Virus Persistence in Semen Ex Vivo.

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Fischer, Robert J; Judson, Seth; Miazgowicz, Kerri; Bushmaker, Trent; Munster, Vincent J

2016-02-01

On March 20, 2015, a case of Ebola virus disease was identified in Liberia that most likely was transmitted through sexual contact. We assessed the efficiency of detecting Ebola virus in semen samples by molecular diagnostics and the stability of Ebola virus in ex vivo semen under simulated tropical conditions.

Onchocerciasis transmission in Ghana: persistence under different control strategies and the role of the simuliid vectors.

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Poppy H L Lamberton

2015-04-01

Full Text Available The World Health Organization (WHO aims at eliminating onchocerciasis by 2020 in selected African countries. Current control focuses on community-directed treatment with ivermectin (CDTI. In Ghana, persistent transmission has been reported despite long-term control. We present spatial and temporal patterns of onchocerciasis transmission in relation to ivermectin treatment history.Host-seeking and ovipositing blackflies were collected from seven villages in four regions of Ghana with 3-24 years of CDTI at the time of sampling. A total of 16,443 flies was analysed for infection; 5,812 (35.3% were dissected for parity (26.9% parous. Heads and thoraces of 12,196 flies were dissected for Onchocerca spp. and DNA from 11,122 abdomens was amplified using Onchocerca primers. A total of 463 larvae (0.03 larvae/fly from 97 (0.6% infected and 62 (0.4% infective flies was recorded; 258 abdomens (2.3% were positive for Onchocerca DNA. Infections (all were O. volvulus were more likely to be detected in ovipositing flies. Transmission occurred, mostly in the wet season, at Gyankobaa and Bosomase, with transmission potentials of, respectively, 86 and 422 L3/person/month after 3 and 6 years of CDTI. The numbers of L3/1,000 parous flies at these villages were over 100 times the WHO threshold of one L3/1,000 for transmission control. Vector species influenced transmission parameters. At Asubende, the number of L3/1,000 ovipositing flies (1.4, 95% CI = 0-4 also just exceeded the threshold despite extensive vector control and 24 years of ivermectin distribution, but there were no infective larvae in host-seeking flies.Despite repeated ivermectin treatment, evidence of O. volvulus transmission was documented in all seven villages and above the WHO threshold in two. Vector species influences transmission through biting and parous rates and vector competence, and should be included in transmission models. Oviposition traps could augment vector collector methods for

Pathogenic characteristics of persistent feline enteric coronavirus infection in cats

Science.gov (United States)

Vogel, Liesbeth; Van der Lubben, Mariken; Te Lintelo, Eddie G.; Bekker, Cornelis P.J.; Geerts, Tamara; Schuijff, Leontine S.; Grinwis, Guy C.M.; Egberink, Herman F.; Rottier, Peter J.M.

2010-01-01

Feline coronaviruses (FCoV) comprise two biotypes: feline enteric coronaviruses (FECV) and feline infectious peritonitis viruses (FIPV). FECV is associated with asymptomatic persistent enteric infections, while FIPV causes feline infectious peritonitis (FIP), a usually fatal systemic disease in domestic cats and some wild Felidae. FIPV arises from FECV by mutation. FCoV also occur in two serotypes, I and II, of which the serotype I viruses are by far the most prevalent in the field. Yet, most of our knowledge about FCoV infections relates to serotype II viruses, particularly about the FIPV, mainly because type I viruses grow poorly in cell culture. Hence, the aim of the present work was the detailed study of the epidemiologically most relevant viruses, the avirulent serotype I viruses. Kittens were inoculated oronasally with different doses of two independent FECV field strains, UCD and RM. Persistent infection could be reproducibly established. The patterns of clinical symptoms, faecal virus shedding and seroconversion were monitored for up to 10 weeks revealing subtle but reproducible differences between the two viruses. Faecal virus, i.e. genomic RNA, was detected during persistent FECV infection only in the large intestine, downstream of the appendix, and could occasionally be observed also in the blood. The implications of our results, particularly our insights into the persistently infected state, are discussed. PMID:20663472

Emerging Vector-Borne Diseases.

Science.gov (United States)

Huntington, Mark K; Allison, Jay; Nair, Dilip

2016-10-01

Several mosquito-borne viral infections have recently emerged in North America; West Nile virus is the most common in the United States. Although West Nile virus generally causes a self-limited, flulike febrile illness, a serious neuroinvasive form may occur. Dengue is the most common vector-borne viral disease worldwide, and it has been a significant public health threat in the United States since 2009. Known as breakbone fever for its severe myalgias and arthralgias, dengue may cause a hemorrhagic syndrome. Chikungunya also causes flulike febrile illness and disabling arthralgias. Although meningoencephalitis may occur with chikungunya, bleeding is uncommon. Symptoms of Zika virus infection are similar to those of dengue, but milder. Zika virus increases the risk of fetal brain abnormalities, including microcephaly, if a pregnant woman is infected. Zika virus is spread through Aedes albopictus mosquito bites, is transmitted sexually, and may rarely spread nonsexually from person to person. Diagnosis of these vectorborne infections is clinical and serologic, and treatment is supportive. Other, well-established vector-borne diseases are also important. Ehrlichiosis is a tick-borne bacterial disease that presents as a nonspecific syndrome of fever, headache, malaise, and myalgias. It is diagnosed via blood smear testing, with confirmatory serology. Ehrlichiosis is treated with doxycycline. Rickettsial infections are transmitted by fleas, mites, and ticks, and severity ranges from mild to life threatening. Rocky Mountain spotted fever, the most significant rickettsial infection, is primarily a clinical diagnosis that presents as fever, headache, myalgias, petechial rash, and tick exposure. Doxycycline is effective for rickettsial infections if administered promptly. Vector avoidance strategies are critical to the prevention of all of these infections.

Dengue virus type 2 infections of Aedes aegypti are modulated by the mosquito's RNA interference pathway.

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Irma Sánchez-Vargas

2009-02-01

Full Text Available A number of studies have shown that both innate and adaptive immune defense mechanisms greatly influence the course of human dengue virus (DENV infections, but little is known about the innate immune response of the mosquito vector Aedes aegypti to arbovirus infection. We present evidence here that a major component of the mosquito innate immune response, RNA interference (RNAi, is an important modulator of mosquito infections. The RNAi response is triggered by double-stranded RNA (dsRNA, which occurs in the cytoplasm as a result of positive-sense RNA virus infection, leading to production of small interfering RNAs (siRNAs. These siRNAs are instrumental in degradation of viral mRNA with sequence homology to the dsRNA trigger and thereby inhibition of virus replication. We show that although dengue virus type 2 (DENV2 infection of Ae. aegypti cultured cells and oral infection of adult mosquitoes generated dsRNA and production of DENV2-specific siRNAs, virus replication and release of infectious virus persisted, suggesting viral circumvention of RNAi. We also show that DENV2 does not completely evade RNAi, since impairing the pathway by silencing expression of dcr2, r2d2, or ago2, genes encoding important sensor and effector proteins in the RNAi pathway, increased virus replication in the vector and decreased the extrinsic incubation period required for virus transmission. Our findings indicate a major role for RNAi as a determinant of DENV transmission by Ae. aegypti.

Assessing Disparities of Dengue Virus Transmission Risk across the US-Mexican Border Using a Climate Driven Vector-Epidemiological Model

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Morin, Cory; Monaghan, Andrew; Quattrochi, Dale; Crosson, William; Hayden, Mary; Ernst, Kacey

2015-01-01

Dengue fever is a mosquito-borne viral disease reemerging throughout much of the tropical Americas. Dengue virus transmission is explicitly influenced by climate and the environment through its primary vector, Aedes aegypti. Temperature regulates Ae. aegypti development, survival, and replication rates as well as the incubation period of the virus within the mosquito. Precipitation provides water for many of the preferred breeding habitats of the mosquito, including buckets, old tires, and other places water can collect. Although transmission regularly occurs along the border region in Mexico, dengue virus transmission in bordering Arizona has not occurred. Using NASA's TRMM (Tropical Rainfall Measuring Mission) satellite for precipitation input and Daymet for temperature and supplemental precipitation input, we modeled dengue transmission along a US-Mexico transect using a dynamic dengue transmission model that includes interacting vector ecology and epidemiological components. Model runs were performed for 5 cities in Sonora, Mexico and southern Arizona. Employing a Monte Carlo approach, we performed ensembles of several thousands of model simulations in order to resolve the model uncertainty arising from using different combinations of parameter values that are not well known. For cities with reported dengue case data, the top model simulations that best reproduced dengue case numbers were retained and their parameter values were extracted for comparison. These parameter values were used to run simulations in areas where dengue virus transmission does not occur or where dengue fever case data was unavailable. Additional model runs were performed to reveal how changes in climate or parameter values could alter transmission risk along the transect. The relative influence of climate variability and model parameters on dengue virus transmission is assessed to help public health workers prepare location specific infection prevention strategies.

New type of Sendai virus vector provides transgene-free iPS cells derived from chimpanzee blood.

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Yasumitsu Fujie

Full Text Available Induced pluripotent stem cells (iPSCs are potentially valuable cell sources for disease models and future therapeutic applications; however, inefficient generation and the presence of integrated transgenes remain as problems limiting their current use. Here, we developed a new Sendai virus vector, TS12KOS, which has improved efficiency, does not integrate into the cellular DNA, and can be easily eliminated. TS12KOS carries KLF4, OCT3/4, and SOX2 in a single vector and can easily generate iPSCs from human blood cells. Using TS12KOS, we established iPSC lines from chimpanzee blood, and used DNA array analysis to show that the global gene-expression pattern of chimpanzee iPSCs is similar to those of human embryonic stem cell and iPSC lines. These results demonstrated that our new vector is useful for generating iPSCs from the blood cells of both human and chimpanzee. In addition, the chimpanzee iPSCs are expected to facilitate unique studies into human physiology and disease.

Persistence of experimental Rocio virus infection in the golden hamster (Mesocricetus auratus

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Daniele Freitas Henriques

2012-08-01

Full Text Available Rocio virus (ROCV is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus. The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR. The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC. ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection.

Relevancia del mosquito tigre (Aedes Albopictus) como vector de enfermedades.

OpenAIRE

Blasco Rivera, Cristina

2017-01-01

El mosquito tigre (Ae. Albopictus) es uno de los vectores de las enfermedades causadas por arbovirus, siendo actualmente, la especie vectorial más invasiva del mundo. Se introdujo en Europa en 1979 localizándose en España por primera vez en agosto de 2004 en San Cugat del Vallés en Barcelona, desde donde no ha dejado de extenderse. Es vector del virus del dengue, virus del chikungunya, virus Zika y virus de la fiebre amarilla. El objetivo principal de este Trabajo de Fin de Grado será realiza...

Efficacy of mineral oil combined with insecticides for the control of aphid virus vectors to reduce potato virus Y infections in seed potatoes (Solanum tuberosum)

DEFF Research Database (Denmark)

Hansen, Lars M.; Nielsen, Steen L.

2012-01-01

Aphids are major vectors of plant viruses. Potato virus Y (PVY) is the most important aphid-transmitted virus affecting potato crops in Denmark. Because of a changed seed potato growing strategy, the seed potato area in Denmark is changing from regions with a low average temperature to regions...... with a higher average temperature. This means that the aphids may infest the potato crops earlier and the population development of the aphids may be faster, and consequently PVY may more easily become epidemic in seed potato crops. With a view to reducing the spread of PVY a 3-year experiment was carried out...... with a combination of mineral oil and insecticides. In 2005 and 2007 when a very high number of aphids were present, nearly all plants were infected with PVY. In 2006 with a lower number of aphids a smaller proportion of the plants were infected, and a tendency to a lower PVY incidence in mineral-oil treated plots...

Immune protection of nonhuman primates against Ebola virus with single low-dose adenovirus vectors encoding modified GPs.

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Nancy J Sullivan

2006-06-01

Full Text Available Ebola virus causes a hemorrhagic fever syndrome that is associated with high mortality in humans. In the absence of effective therapies for Ebola virus infection, the development of a vaccine becomes an important strategy to contain outbreaks. Immunization with DNA and/or replication-defective adenoviral vectors (rAd encoding the Ebola glycoprotein (GP and nucleoprotein (NP has been previously shown to confer specific protective immunity in nonhuman primates. GP can exert cytopathic effects on transfected cells in vitro, and multiple GP forms have been identified in nature, raising the question of which would be optimal for a human vaccine.To address this question, we have explored the efficacy of mutant GPs from multiple Ebola virus strains with reduced in vitro cytopathicity and analyzed their protective effects in the primate challenge model, with or without NP. Deletion of the GP transmembrane domain eliminated in vitro cytopathicity but reduced its protective efficacy by at least one order of magnitude. In contrast, a point mutation was identified that abolished this cytopathicity but retained immunogenicity and conferred immune protection in the absence of NP. The minimal effective rAd dose was established at 10(10 particles, two logs lower than that used previously.Expression of specific GPs alone vectored by rAd are sufficient to confer protection against lethal challenge in a relevant nonhuman primate model. Elimination of NP from the vaccine and dose reductions to 10(10 rAd particles do not diminish protection and simplify the vaccine, providing the basis for selection of a human vaccine candidate.

Immune Protection of Nonhuman Primates against Ebola Virus with Single Low-Dose Adenovirus Vectors Encoding Modified GPs

Science.gov (United States)

Geisbert, Joan B; Shedlock, Devon J; Xu, Ling; Lamoreaux, Laurie; Custers, Jerome H. H. V; Popernack, Paul M; Yang, Zhi-Yong; Pau, Maria G; Roederer, Mario; Koup, Richard A; Goudsmit, Jaap; Jahrling, Peter B; Nabel, Gary J

2006-01-01

Background Ebola virus causes a hemorrhagic fever syndrome that is associated with high mortality in humans. In the absence of effective therapies for Ebola virus infection, the development of a vaccine becomes an important strategy to contain outbreaks. Immunization with DNA and/or replication-defective adenoviral vectors (rAd) encoding the Ebola glycoprotein (GP) and nucleoprotein (NP) has been previously shown to confer specific protective immunity in nonhuman primates. GP can exert cytopathic effects on transfected cells in vitro, and multiple GP forms have been identified in nature, raising the question of which would be optimal for a human vaccine. Methods and Findings To address this question, we have explored the efficacy of mutant GPs from multiple Ebola virus strains with reduced in vitro cytopathicity and analyzed their protective effects in the primate challenge model, with or without NP. Deletion of the GP transmembrane domain eliminated in vitro cytopathicity but reduced its protective efficacy by at least one order of magnitude. In contrast, a point mutation was identified that abolished this cytopathicity but retained immunogenicity and conferred immune protection in the absence of NP. The minimal effective rAd dose was established at 1010 particles, two logs lower than that used previously. Conclusions Expression of specific GPs alone vectored by rAd are sufficient to confer protection against lethal challenge in a relevant nonhuman primate model. Elimination of NP from the vaccine and dose reductions to 1010 rAd particles do not diminish protection and simplify the vaccine, providing the basis for selection of a human vaccine candidate. PMID:16683867

Distribution, persistence and interchange of Epstein-Barr virus strains among PBMC, plasma and saliva of primary infection subjects.

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Kwok, Hin; Chan, Koon Wing; Chan, Kwok Hung; Chiang, Alan Kwok Shing

2015-01-01

Our study aimed at investigating the distribution, persistence and interchange of viral strains among peripheral blood mononuclear cells (PBMC), plasma and saliva of primary Epstein-Barr virus (EBV) infection subjects. Twelve infectious mononucleosis (IM) patients and eight asymptomatic individuals (AS) with primary EBV infection were followed longitudinally at several time points for one year from the time of diagnosis, when blood and saliva samples were collected and separated into PBMC, plasma and saliva, representing circulating B cell, plasma and epithelial cell compartments, respectively. To survey the viral strains, genotyping assays for the natural polymorphisms in two latent EBV genes, EBNA2 and LMP1, were performed and consisted of real-time PCR on EBNA2 to distinguish type 1 and 2 viruses, fluorescent-based 30-bp typing assay on LMP1 to distinguish deletion and wild type LMP1, and fluorescent-based heteroduplex tracking assays on both EBNA2 and LMP1 to distinguish defined polymorphic variants. No discernible differences were observed between IM patients and AS. Multiple viral strains were acquired early at the start of infection. Stable persistence of dominant EBV strains in the same tissue compartment was observed throughout the longitudinal samples. LMP1-defined strains, China 1, China 2 and Mediterranean+, were the most common strains observed. EBNA2-defined groups 1 and 3e predominated the PBMC and saliva compartments. Concordance of EBNA2 and LMP1 strains between PBMC and saliva suggested ready interchange of viruses between circulating B cell and epithelial cell pools, whilst discordance of viral strains observed between plasma and PBMC/saliva indicated presence of viral pools in other undetermined tissue compartments. Taken together, the results indicated that the distribution, persistence and interchange of viral strains among the tissue compartments are more complex than those proposed by the current model of EBV life cycle.

Foxp3+ regulatory T cells control persistence of viral CNS infection.

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Dajana Reuter

Full Text Available We earlier established a model of a persistent viral CNS infection using two week old immunologically normal (genetically unmodified mice and recombinant measles virus (MV. Using this model infection we investigated the role of regulatory T cells (Tregs as regulators of the immune response in the brain, and assessed whether the persistent CNS infection can be modulated by manipulation of Tregs in the periphery. CD4(+ CD25(+ Foxp3(+ Tregs were expanded or depleted during the persistent phase of the CNS infection, and the consequences for the virus-specific immune response and the extent of persistent infection were analyzed. Virus-specific CD8(+ T cells predominantly recognising the H-2D(b-presented viral hemagglutinin epitope MV-H(22-30 (RIVINREHL were quantified in the brain by pentamer staining. Expansion of Tregs after intraperitoneal (i.p. application of the superagonistic anti-CD28 antibody D665 inducing transient immunosuppression caused increased virus replication and spread in the CNS. In contrast, depletion of Tregs using diphtheria toxin (DT in DEREG (depletion of regulatory T cells-mice induced an increase of virus-specific CD8(+ effector T cells in the brain and caused a reduction of the persistent infection. These data indicate that manipulation of Tregs in the periphery can be utilized to regulate virus persistence in the CNS.

Characterization of thymus-associated lymphoid depletion in bovine calves acutely or persistently infected with bovine viral diarrhea virus 1, bovine viral diarrhea 2 or HoBi-like pestivirus

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Viruses from recognized pestivirus species bovine viral diarrhea 1 (BVDV-1) and BVDV-2 and the proposed pestivirus species HoBi-like virus infect primarily cattle. Exposure of cattle to these viruses can lead to either acute or persistent infections depending on the timing and status of the animal ...

Interaction of measles virus vectors with Auger electron emitting radioisotopes

International Nuclear Information System (INIS)

Dingli, David; Peng, K.-W.; Harvey, Mary E.; Vongpunsawad, Sompong; Bergert, Elizabeth R.; Kyle, Robert A.; Cattaneo, Roberto; Morris, John C.; Russell, Stephen J.

2005-01-01

A recombinant measles virus (MV) expressing the sodium iodide symporter (NIS) is being considered for therapy of advanced multiple myeloma. Auger electrons selectively damage cells in which the isotope decays. We hypothesized that the Auger electron emitting isotope 125 I can be used to control viral proliferation. MV was engineered to express both carcinoembryonic antigen and NIS (MV-NICE). Cells were infected with MV-NICE and exposed to 125 I with appropriate controls. MV-NICE replication in vitro is inhibited by the selective uptake of 125 I by cells expressing NIS. Auger electron damage is partly mediated by free radicals and abrogated by glutathione. In myeloma xenografts, control of MV-NICE with 125 I was not possible under the conditions of the experiment. MV-NICE does not replicate faster in the presence of radiation. Auger electron emitting isotopes effectively stop propagation of MV vectors expressing NIS in vitro. Additional work is necessary to translate these observations in vivo

Vector status of Aedes species determines geographical risk of autochthonous Zika virus establishment.

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Lauren Gardner

2017-03-01

Full Text Available The 2015-16 Zika virus pandemic originating in Latin America led to predictions of a catastrophic global spread of the disease. Since the current outbreak began in Brazil in May 2015 local transmission of Zika has been reported in over 60 countries and territories, with over 750 thousand confirmed and suspected cases. As a result of its range expansion attention has focused on possible modes of transmission, of which the arthropod vector-based disease spread cycle involving Aedes species is believed to be the most important. Additional causes of concern are the emerging new links between Zika disease and Guillain-Barre Syndrome (GBS, and a once rare congenital disease, microcephaly.Like dengue and chikungunya, the geographic establishment of Zika is thought to be limited by the occurrence of its principal vector mosquito species, Ae. aegypti and, possibly, Ae. albopictus. While Ae. albopictus populations are more widely established than those of Ae. aegypti, the relative competence of these species as a Zika vector is unknown. The analysis reported here presents a global risk model that considers the role of each vector species independently, and quantifies the potential spreading risk of Zika into new regions. Six scenarios are evaluated which vary in the weight assigned to Ae. albopictus as a possible spreading vector. The scenarios are bounded by the extreme assumptions that spread is driven by air travel and Ae. aegypti presence alone and spread driven equally by both species. For each scenario destination cities at highest risk of Zika outbreaks are prioritized, as are source cities in affected regions. Finally, intercontinental air travel routes that pose the highest risk for Zika spread are also ranked. The results are compared between scenarios.Results from the analysis reveal that if Ae. aegypti is the only competent Zika vector, then risk is geographically limited; in North America mainly to Florida and Texas. However, if Ae

Gene Transfer of Glutamic Acid Decarboxylase 67 by Herpes Simplex Virus Vectors Suppresses Neuropathic Pain Induced by Human Immunodeficiency Virus gp120 Combined with ddC in Rats.

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Kanao, Megumi; Kanda, Hirotsugu; Huang, Wan; Liu, Shue; Yi, Hyun; Candiotti, Keith A; Lubarsky, David A; Levitt, Roy C; Hao, Shuanglin

2015-06-01

Human immunodeficiency virus (HIV)-related painful sensory neuropathies primarily consist of the HIV infection-related distal sensory polyneuropathy and antiretroviral toxic neuropathies. Pharmacotherapy provides only partial relief of pain in patients with HIV/acquired immune deficiency syndrome because little is known about the exact neuropathological mechanisms for HIV-associated neuropathic pain (NP). Hypofunction of γ-aminobutyric acid (GABA) GABAergic inhibitory mechanisms has been reported after peripheral nerve injury. In this study, we tested the hypothesis that HIV gp120 combined with antiretroviral therapy reduces spinal GABAergic inhibitory tone and that restoration of GABAergic inhibitory tone will reduce HIV-related NP in a rat model. The application of recombinant HIV-1 envelope protein gp120 into the sciatic nerve plus systemic ddC (one antiretroviral drug) induced mechanical allodynia. The hind paws of rats were inoculated with replication-defective herpes simplex virus (HSV) vectors genetically encoding gad1 gene to express glutamic acid decarboxylase 67 (GAD67), an enzyme that catalyzes the decarboxylation of glutamate to GABA. Mechanical threshold was tested using von Frey filaments before and after treatments with the vectors. The expression of GAD67 in both the lumbar spinal cord and the L4-5 dorsal root ganglia was examined using western blots. The expression of mitochondrial superoxide in the spinal dorsal horn was examined using MitoSox imaging. The immunoreactivity of spinal GABA, pCREB, and pC/EBPβ was tested using immunohistochemistry. In the gp120 with ddC-induced neuropathic pain model, GAD67 expression mediated by the HSV vector caused an elevation of mechanical threshold that was apparent on day 3 after vector inoculation. The antiallodynic effect of the single HSV vector inoculation expressing GAD67 lasted >28 days. The area under the time-effect curves in the HSV vector expressing GAD67 was increased compared with that in the

Rift Valley fever virus: strategies for maintenance, survival and vertical transmission in mosquitoes.

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Lumley, Sarah; Horton, Daniel L; Hernandez-Triana, Luis L M; Johnson, Nicholas; Fooks, Anthony R; Hewson, Roger

2017-05-01

Rift Valley fever virus (RVFV) is a mosquito-borne arbovirus causing severe disease in humans and ruminants. Spread of RVFV out of Africa has raised concerns that it could emerge in Europe or the USA. Virus persistence is dependent on successful infection of, replication in, and transmission to susceptible vertebrate and invertebrate hosts, modulated by virus-host and vector-virus interactions. The principal accepted theory for the long-term maintenance of RVFV involves vertical transmission (VT) of virus to mosquito progeny, with the virus surviving long inter-epizootic periods within the egg. This VT hypothesis, however, is yet to be comprehensively proven. Here, evidence for and against the VT of RVFV is reviewed along with the identification of factors limiting its detection in natural and experimental data. The observations of VT for other arboviruses in the genera Alphavirus, Flavivirus and Orthobunyavirus are discussed within the context of RVFV. The review concludes that VT of RVFV is likely but that current data are insufficient to irrefutably prove this hypothesis.

Advances and Future Challenges in Recombinant Adenoviral Vectored H5N1 Influenza Vaccines

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Jianfeng Zhang

2012-11-01

Full Text Available The emergence of a highly pathogenic avian influenza virus H5N1 has increased the potential for a new pandemic to occur. This event highlights the necessity for developing a new generation of influenza vaccines to counteract influenza disease. These vaccines must be manufactured for mass immunization of humans in a timely manner. Poultry should be included in this policy, since persistent infected flocks are the major source of avian influenza for human infections. Recombinant adenoviral vectored H5N1 vaccines are an attractive alternative to the currently licensed influenza vaccines. This class of vaccines induces a broadly protective immunity against antigenically distinct H5N1, can be manufactured rapidly, and may allow mass immunization of human and poultry. Recombinant adenoviral vectors derived from both human and non-human adenoviruses are currently being investigated and appear promising both in nonclinical and clinical studies. This review will highlight the current status of various adenoviral vectored H5N1 vaccines and will outline novel approaches for the future.

Vaccine efficacy against malaria by the combination of porcine parvovirus-like particles and vaccinia virus vectors expressing CS of Plasmodium.

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Rodríguez, Dolores; González-Aseguinolaza, Gloria; Rodríguez, Juan R; Vijayan, Aneesh; Gherardi, Magdalena; Rueda, Paloma; Casal, J Ignacio; Esteban, Mariano

2012-01-01

With the aim to develop an efficient and cost-effective approach to control malaria, we have generated porcine parvovirus-like particles (PPV-VLPs) carrying the CD8(+) T cell epitope (SYVPSAEQI) of the circumsporozoite (CS) protein from Plasmodium yoelii fused to the PPV VP2 capsid protein (PPV-PYCS), and tested in prime/boost protocols with poxvirus vectors for efficacy in a rodent malaria model. As a proof-of concept, we have characterized the anti-CS CD8(+) T cell response elicited by these hybrid PPV-VLPs in BALB/c mice after immunizations with the protein PPV-PYCS administered alone or in combination with recombinant vaccinia virus (VACV) vectors from the Western Reserve (WR) and modified virus Ankara (MVA) strains expressing the entire P. yoelii CS protein. The results of different immunization protocols showed that the combination of PPV-PYCS prime/poxvirus boost was highly immunogenic, inducing specific CD8+ T cell responses to CS resulting in 95% reduction in liver stage parasites two days following sporozoite challenge. In contrast, neither the administration of PPV-PYCS alone nor the immunization with the vectors given in the order poxvirus/VLPs was as effective. The immune profile induced by VLPs/MVA boost was associated with polyfunctional and effector memory CD8+ T cell responses. These findings highlight the use of recombinant parvovirus PPV-PYCS particles as priming agents and poxvirus vectors, like MVA, as booster to enhance specific CD8+ T cell responses to Plasmodium antigens and to control infection. These observations are relevant in the design of T cell-inducing vaccines against malaria.

Virus diseases of peppers (Capsicum spp.) and their control.

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Kenyon, Lawrence; Kumar, Sanjeet; Tsai, Wen-Shi; Hughes, Jacqueline d'A

2014-01-01

The number of virus species infecting pepper (Capsicum spp.) crops and their incidences has increased considerably over the past 30 years, particularly in tropical and subtropical pepper production systems. This is probably due to a combination of factors, including the expansion and intensification of pepper cultivation in these regions, the increased volume and speed of global trade of fresh produce (including peppers) carrying viruses and vectors to new locations, and perhaps climate change expanding the geographic range suitable for the viruses and vectors. With the increased incidences of diverse virus species comes increased incidences of coinfection with two or more virus species in the same plant. There is then greater chance of synergistic interactions between virus species, increasing symptom severity and weakening host resistance, as well as the opportunity for genetic recombination and component exchange and a possible increase in aggressiveness, virulence, and transmissibility. The main virus groups infecting peppers are transmitted by aphids, whiteflies, or thrips, and a feature of many populations of these vector groups is that they can develop resistance to some of the commonly used insecticides relatively quickly. This, coupled with the increasing concern over the impact of over- or misuse of insecticides on the environment, growers, and consumers, means that there should be less reliance on insecticides to control the vectors of viruses infecting pepper crops. To improve the durability of pepper crop protection measures, there should be a shift away from the broadscale use of insecticides and the use of single, major gene resistance to viruses. Instead, integrated and pragmatic virus control measures should be sought that combine (1) cultural practices that reduce sources of virus inoculum and decrease the rate of spread of viruliferous vectors into the pepper crop, (2) synthetic insecticides, which should be used judiciously and only when the

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bovine Virus Diarrhea Vaccine, Killed Virus. 113.215 Section 113.215 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD...

Correction of mutant Fanconi anemia gene by homologous recombination in human hematopoietic cells using adeno-associated virus vector.

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Paiboonsukwong, Kittiphong; Ohbayashi, Fumi; Shiiba, Haruka; Aizawa, Emi; Yamashita, Takayuki; Mitani, Kohnosuke

2009-11-01

Adeno-associated virus (AAV) vectors have been shown to correct a variety of mutations in human cells by homologous recombination (HR) at high rates, which can overcome insertional mutagenesis and transgene silencing, two of the major hurdles in conventional gene addition therapy of inherited diseases. We examined an ability of AAV vectors to repair a mutation in human hematopoietic cells by HR. We infected a human B-lymphoblastoid cell line (BCL) derived from a normal subject with an AAV, which disrupts the hypoxanthine phosphoribosyl transferase1 (HPRT1) locus, to measure the frequency of AAV-mediated HR in BCL cells. We subsequently constructed an AAV vector encoding the normal sequences from the Fanconi anemia group A (FANCA) locus to correct a mutation in the gene in BCL derived from a FANCA patient. Under optimal conditions, approximately 50% of BCL cells were transduced with an AAV serotype 2 (AAV-2) vector. In FANCA BCL cells, up to 0.016% of infected cells were gene-corrected by HR. AAV-mediated restoration of normal genotypic and phenotypic characteristics in FANCA-mutant cells was confirmed at the DNA, protein and functional levels. The results obtained in the present study indicate that AAV vectors may be applicable for gene correction therapy of inherited hematopoietic disorders.

Complexities in Isolation and Purification of Multiple Viruses from Mixed Viral Infections: Viral Interference, Persistence and Exclusion.

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Naveen Kumar

Full Text Available Successful purification of multiple viruses from mixed infections remains a challenge. In this study, we investigated peste des petits ruminants virus (PPRV and foot-and-mouth disease virus (FMDV mixed infection in goats. Rather than in a single cell type, cytopathic effect (CPE of the virus was observed in cocultured Vero/BHK-21 cells at 6th blind passage (BP. PPRV, but not FMDV could be purified from the virus mixture by plaque assay. Viral RNA (mixture transfection in BHK-21 cells produced FMDV but not PPRV virions, a strategy which we have successfully employed for the first time to eliminate the negative-stranded RNA virus from the virus mixture. FMDV phenotypes, such as replication competent but noncytolytic, cytolytic but defective in plaque formation and, cytolytic but defective in both plaque formation and standard FMDV genome were observed respectively, at passage level BP8, BP15 and BP19 and hence complicated virus isolation in the cell culture system. Mixed infection was not found to induce any significant antigenic and genetic diversity in both PPRV and FMDV. Further, we for the first time demonstrated the viral interference between PPRV and FMDV. Prior transfection of PPRV RNA, but not Newcastle disease virus (NDV and rotavirus RNA resulted in reduced FMDV replication in BHK-21 cells suggesting that the PPRV RNA-induced interference was specifically directed against FMDV. On long-term coinfection of some acute pathogenic viruses (all possible combinations of PPRV, FMDV, NDV and buffalopox virus in Vero cells, in most cases, one of the coinfecting viruses was excluded at passage level 5 suggesting that the long-term coinfection may modify viral persistence. To the best of our knowledge, this is the first documented evidence describing a natural mixed infection of FMDV and PPRV. The study not only provides simple and reliable methodologies for isolation and purification of two epidemiologically and economically important groups of

New frontiers in oncolytic viruses: optimizing and selecting for virus strains with improved efficacy

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Lundstrom K

2018-02-01

Full Text Available Kenneth Lundstrom PanTherapeutics, Lutry, Switzerland Abstract: Oncolytic viruses have demonstrated selective replication and killing of tumor cells. Different types of oncolytic viruses – adenoviruses, alphaviruses, herpes simplex viruses, Newcastle disease viruses, rhabdoviruses, Coxsackie viruses, and vaccinia viruses – have been applied as either naturally occurring or engineered vectors. Numerous studies in animal-tumor models have demonstrated substantial tumor regression and prolonged survival rates. Moreover, clinical trials have confirmed good safety profiles and therapeutic efficacy for oncolytic viruses. Most encouragingly, the first cancer gene-therapy drug – Gendicine, based on oncolytic adenovirus type 5 – was approved in China. Likewise, a second-generation oncolytic herpes simplex virus-based drug for the treatment of melanoma has been registered in the US and Europe as talimogene laherparepvec. Keywords: immunotherapy, viral vectors, clinical trials, drug approval

Next generation of adeno-associated virus 2 vectors: Point mutations in tyrosines lead to high-efficiency transduction at lower doses

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Zhong, Li; Li, Baozheng; Mah, Cathryn S.; Govindasamy, Lakshmanan; Agbandje-McKenna, Mavis; Cooper, Mario; Herzog, Roland W.; Zolotukhin, Irene; Warrington, Kenneth H.; Weigel-Van Aken, Kirsten A.; Hobbs, Jacqueline A.; Zolotukhin, Sergei; Muzyczka, Nicholas; Srivastava, Arun

2008-01-01

Recombinant adeno-associated virus 2 (AAV2) vectors are in use in several Phase I/II clinical trials, but relatively large vector doses are needed to achieve therapeutic benefits. Large vector doses also trigger an immune response as a significant fraction of the vectors fails to traffic efficiently to the nucleus and is targeted for degradation by the host cell proteasome machinery. We have reported that epidermal growth factor receptor protein tyrosine kinase (EGFR-PTK) signaling negatively affects transduction by AAV2 vectors by impairing nuclear transport of the vectors. We have also observed that EGFR-PTK can phosphorylate AAV2 capsids at tyrosine residues. Tyrosine-phosphorylated AAV2 vectors enter cells efficiently but fail to transduce effectively, in part because of ubiquitination of AAV capsids followed by proteasome-mediated degradation. We reasoned that mutations of the surface-exposed tyrosine residues might allow the vectors to evade phosphorylation and subsequent ubiquitination and, thus, prevent proteasome-mediated degradation. Here, we document that site-directed mutagenesis of surface-exposed tyrosine residues leads to production of vectors that transduce HeLa cells ≈10-fold more efficiently in vitro and murine hepatocytes nearly 30-fold more efficiently in vivo at a log lower vector dose. Therapeutic levels of human Factor IX (F.IX) are also produced at an ≈10-fold reduced vector dose. The increased transduction efficiency of tyrosine-mutant vectors is due to lack of capsid ubiquitination and improved intracellular trafficking to the nucleus. These studies have led to the development of AAV vectors that are capable of high-efficiency transduction at lower doses, which has important implications in their use in human gene therapy. PMID:18511559

RNA Interference in Insect Vectors for Plant Viruses

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Surapathrudu Kanakala

2016-12-01

Full Text Available Insects and other arthropods are the most important vectors of plant pathogens. The majority of plant pathogens are disseminated by arthropod vectors such as aphids, beetles, leafhoppers, planthoppers, thrips and whiteflies. Transmission of plant pathogens and the challenges in managing insect vectors due to insecticide resistance are factors that contribute to major food losses in agriculture. RNA interference (RNAi was recently suggested as a promising strategy for controlling insect pests, including those that serve as important vectors for plant pathogens. The last decade has witnessed a dramatic increase in the functional analysis of insect genes, especially those whose silencing results in mortality or interference with pathogen transmission. The identification of such candidates poses a major challenge for increasing the role of RNAi in pest control. Another challenge is to understand the RNAi machinery in insect cells and whether components that were identified in other organisms are also present in insect. This review will focus on summarizing success cases in which RNAi was used for silencing genes in insect vector for plant pathogens, and will be particularly helpful for vector biologists.

Virus-host interaction in feline immunodeficiency virus (FIV) infection.

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Taniwaki, Sueli Akemi; Figueiredo, Andreza Soriano; Araujo, João Pessoa

2013-12-01

Feline immunodeficiency virus (FIV) infection has been the focus of several studies because this virus exhibits genetic and pathogenic characteristics that are similar to those of the human immunodeficiency virus (HIV). FIV causes acquired immunodeficiency syndrome (AIDS) in cats, nevertheless, a large fraction of infected cats remain asymptomatic throughout life despite of persistent chronic infection. This slow disease progression may be due to the presence of factors that are involved in the natural resistance to infection and the immune response that is mounted by the animals, as well as due to the adaptation of the virus to the host. Therefore, the study of virus-host interaction is essential to the understanding of the different patterns of disease course and the virus persistence in the host, and to help with the development of effective vaccines and perhaps the cure of FIV and HIV infections. Copyright © 2013 Elsevier Ltd. All rights reserved.

Is there a role for symbiotic bacteria in plant virus transmission?

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During the process of circulative plant virus transmission by insect vectors, viruses interact with different insect vector tissues prior to transmission to a new host plant. An area of intense debate in the field is whether bacterial symbionts of insect vectors are involved in the virus transmissi...

New Insights Into the Transmissibility of Leishmania infantum From Dogs to Sand Flies: Experimental Vector-Transmission Reveals Persistent Parasite Depots at Bite Sites.

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Aslan, Hamide; Oliveira, Fabiano; Meneses, Claudio; Castrovinci, Philip; Gomes, Regis; Teixeira, Clarissa; Derenge, Candace A; Orandle, Marlene; Gradoni, Luigi; Oliva, Gaetano; Fischer, Laurent; Valenzuela, Jesus G; Kamhawi, Shaden

2016-06-01

Canine leishmaniasis (CanL) is a chronic fatal disease of dogs and a major source of human infection through propagation of parasites in vectors. Here, we infected 8 beagles through multiple experimental vector transmissions with Leishmania infantum-infected Lutzomyia longipalpis. CanL clinical signs varied, although live parasites were recovered from all dog spleens. Splenic parasite burdens correlated positively with Leishmania-specific interleukin 10 levels, negatively with Leishmania-specific interferon γ and interleukin 2 levels, and negatively with Leishmania skin test reactivity. A key finding was parasite persistence for 6 months in lesions observed at the bite sites in all dogs. These recrudesced following a second transmission performed at a distal site. Notably, sand flies efficiently acquired parasites after feeding on lesions at the primary bite site. In this study, controlled vector transmissions identify a potentially unappreciated role for skin at infectious bite sites in dogs with CanL, providing a new perspective regarding the mechanism of Leishmania transmissibility to vector sand flies. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

Persistence of chicken anemia virus antigen and inclusions in spontaneous cases of Marek's disease visceral lymphomas in broiler chickens at slaughterhouses.

Science.gov (United States)

Ahmed, Mohamed Sabry; Ono, Hiroki; Sasaki, Jun; Ochiai, Kenji; Goryo, Masanobu

2016-06-01

The chicken anemia virus (CAV) and Marek's disease virus (MDV) infect chickens worldwide; a single or dual infection by these viruses has a great impact on poultry production. In the present study, we examined the existence of CAV antigen and its inclusions in Marek's disease (MD) lymphomas in chickens in the slaughterhouses of Iwate prefecture, Japan. Forty-nine spleens and 13 livers with different degrees of nodular lesions were histopathologically examined at our laboratory. Grossly, the tested organs showed various sizes and anatomical architectures. Based on the cellular morphology and the infiltrative nature of the neoplastic lymphocytes, MD was confirmed in 76% (37/49) of the spleens and 92% (12/13) of the livers. The lesions of MD, according to the pattern of lymphocytic accumulation in the affected organs, were divided into multifocal, coalesced and diffuse. CAV intranuclear inclusion bodies were detected within the small and the large bizarre lymphocytes of the MD lymphomas in 2 livers and 9 spleens, and the immunostaining test for CAV confirmed the persistence of CAV antigens and inclusions in the neoplastic cells. This study demonstrated the persistence of CAV infection within the neoplastic cells of naturally occurring MD lymphomas in chickens.

Vectores recombinantes basados en el virus modificado de ankara (MVA) como vacunas preventivas y terapéuticas contra el SIDA

OpenAIRE

Heeney, Jonathan L.; Mooij, Petra; Nájera García, José Luis; Jiménez, Victoria; Esteban, Mariano; Gómez, Carmen E.

2005-01-01

Vectores Recombinantes basados en el Virus Modificado de Ankara (MVA) como Vacunas Preventivas y Terapéuticas contra el SIDA. Losvirus recombinantes de la invención contienen secuencias que se encuentran insertadas en el mismo sitio de inserción del MVA y permiten la expresión simultánea de varios antígenos, una proteína Env del VIH-I consistente en una proteína gpl20 carente de secuencias correspondientes a la proteína gp41, y una proteína quiméricade fusión de Gag, Pol y Nef. Son virus esta...

The Drosophila Nora virus is an enteric virus, transmitted via feces.

Science.gov (United States)

Habayeb, Mazen S; Cantera, Rafael; Casanova, Gabriela; Ekström, Jens-Ola; Albright, Shannon; Hultmark, Dan

2009-04-01

The biology of the Drosophila viruses has not been intensely investigated. Here we have investigated the biology of the Nora virus, a persistent Drosophila virus. We find that injected Nora virus is able to replicate in the files, reaching a high titer that is maintained in the next generation. There is a remarkable variation in the viral loads of individual flies in persistently infected stocks; the titers can differ by three orders of magnitude. The Nora virus is mainly found in the intestine of infected flies, and the histology of these infected intestines show increased vacuolization. The virus is excreted in the feces and is horizontally transmitted. The Nora virus infection has a very mild effect on the longevity of the flies, and no significant effect on the number of eggs laid and the percent of eggs that develop to adults.

A small and efficient dimerization/packaging signal of rat VL30 RNA and its use in murine leukemia virus-VL30-derived vectors for gene transfer.

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Torrent, C; Gabus, C; Darlix, J L

1994-02-01

Retroviral genomes consist of two identical RNA molecules associated at their 5' ends by the dimer linkage structure located in the packaging element (Psi or E) necessary for RNA dimerization in vitro and packaging in vivo. In murine leukemia virus (MLV)-derived vectors designed for gene transfer, the Psi + sequence of 600 nucleotides directs the packaging of recombinant RNAs into MLV virions produced by helper cells. By using in vitro RNA dimerization as a screening system, a sequence of rat VL30 RNA located next to the 5' end of the Harvey mouse sarcoma virus genome and as small as 67 nucleotides was found to form stable dimeric RNA. In addition, a purine-rich sequence located at the 5' end of this VL30 RNA seems to be critical for RNA dimerization. When this VL30 element was extended by 107 nucleotides at its 3' end and inserted into an MLV-derived vector lacking MLV Psi +, it directed the efficient encapsidation of recombinant RNAs into MLV virions. Because this VL30 packaging signal is smaller and more efficient in packaging recombinant RNAs than the MLV Psi + and does not contain gag or glyco-gag coding sequences, its use in MLV-derived vectors should render even more unlikely recombinations which could generate replication-competent viruses. Therefore, utilization of the rat VL30 packaging sequence should improve the biological safety of MLV vectors for human gene transfer.

Astrocytes play a key role in activation of microglia by persistent Borna disease virus infection

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Sauder Christian

2008-11-01

Full Text Available Abstract Neonatal Borna disease virus (BDV infection of the rat brain is associated with microglial activation and damage to certain neuronal populations. Since persistent BDV infection of neurons is nonlytic in vitro, activated microglia have been suggested to be responsible for neuronal cell death in vivo. However, the mechanisms of activation of microglia in neonatally BDV-infected rat brains remain unclear. Our previous studies have shown that activation of microglia by BDV in culture requires the presence of astrocytes as neither the virus nor BDV-infected neurons alone activate microglia. Here, we evaluated the mechanisms whereby astrocytes can contribute to activation of microglia in neuron-glia-microglia mixed cultures. We found that persistent infection of neuronal cells leads to activation of uninfected astrocytes as measured by elevated expression of RANTES. Activation of astrocytes then produces activation of microglia as evidenced by increased formation of round-shaped, MHCI-, MHCII- and IL-6-positive microglia cells. Our analysis of possible molecular mechanisms of activation of astrocytes and/or microglia in culture indicates that the mediators of activation may be soluble heat-resistant, low molecular weight factors. The findings indicate that astrocytes may mediate activation of microglia by BDV-infected neurons. The data are consistent with the hypothesis that microglia activation in the absence of neuronal damage may represent initial steps in the gradual neurodegeneration observed in brains of neonatally BDV-infected rats.

Complex adenovirus-vectored vaccine protects guinea pigs from three strains of Marburg virus challenges

International Nuclear Information System (INIS)

Wang Danher; Hevey, Michael; Juompan, Laure Y.; Trubey, Charles M.; Raja, Nicholas U.; Deitz, Stephen B.; Woraratanadharm, Jan; Luo Min; Yu Hong; Swain, Benjamin M.; Moore, Kevin M.; Dong, John Y.

2006-01-01

The Marburg virus (MARV), an African filovirus closely related to the Ebola virus, causes a deadly hemorrhagic fever in humans, with up to 90% mortality. Currently, treatment of disease is only supportive, and no vaccines are available to prevent spread of MARV infections. In order to address this need, we have developed and characterized a novel recombinant vaccine that utilizes a single complex adenovirus-vectored vaccine (cAdVax) to overexpress a MARV glycoprotein (GP) fusion protein derived from the Musoke and Ci67 strains of MARV. Vaccination with the cAdVaxM(fus) vaccine led to efficient production of MARV-specific antibodies in both mice and guinea pigs. Significantly, guinea pigs vaccinated with at least 5 x 10 7 pfu of cAdVaxM(fus) vaccine were 100% protected against lethal challenges by the Musoke, Ci67 and Ravn strains of MARV, making it a vaccine with trivalent protective efficacy. Therefore, the cAdVaxM(fus) vaccine serves as a promising vaccine candidate to prevent and contain multi-strain infections by MARV

Some models for epidemics of vector-transmitted diseases

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Fred Brauer

2016-10-01

Full Text Available Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birth defects.We formulate and analyze two epidemic models for vector-transmitted diseases, one appropriate for dengue and chikungunya fever outbreaks and one that includes direct transmission appropriate for Zika virus outbreaks. This is especially important because the Zika virus is the first example of a disease that can be spread both indirectly through a vector and directly (through sexual contact. In both cases, we obtain expressions for the basic reproduction number and show how to use the initial exponential growth rate to estimate the basic reproduction number. However, for the model that includes direct transmission some additional data would be needed to identify the fraction of cases transmitted directly. Data for the 2015 Zika virus outbreak in Barranquilla, Colombia has been used to fit parameters to the model developed here and to estimate the basic reproduction number.

Rack-1, GAPDH3, and actin: proteins of Myzus persicae potentially involved in the transcytosis of beet western yellows virus particles in the aphid

International Nuclear Information System (INIS)

Seddas, Pascale; Boissinot, Sylvaine; Strub, Jean-Marc; Dorsselaer, Alain van; Regenmortel, Marc H.V. van; Pattus, Franc

2004-01-01

Beet western yellows virus (BWYV) is a Polerovirus that relies on the aphid Myzus persicae for its transmission, in a persistent-circulative mode. To be transmitted, the virus must cross the midgut and the accessory salivary glands (ASG) epithelial barriers in a transcytosis mechanism where vector receptors interact with virions. In this paper, we report in vitro interaction experiments between BWYV and aphid components. Using the M. persicae clone from Colmar, we showed that a set of aphid polypeptides, separated by SDS-PAGE or 2D electrophoresis (2DE), can bind in vitro to purified wild type or mutant particles. Using subcellular fractionation, we showed that the 65-kDa polypeptide identified as symbionin is a soluble protein whereas the other polypeptides seem to be associated more or less strongly to the membrane. We hypothesize that three polypeptides, identified by mass spectrometry as Rack-1, GAPDH3, and actin, may be involved in the epithelial transcytosis of virus particles in the aphid vector

Zika virus, vectors, reservoirs, amplifying hosts, and their potential to spread worldwide: what we know and what we should investigate urgently

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Rengina Vorou

2016-07-01

Conclusions: It is a public health imperative to define the domestic and wild animal reservoirs, amplification hosts, and vector capacity of the genera Aedes, Anopheles, and Mansonia. These variables will define the geographic distribution of Zika virus along with the indicated timing and scale of the environmental public health interventions worldwide.

Geminivirus vectors for high-level expression of foreign proteins in plant cells.

Science.gov (United States)

Mor, Tsafrir S; Moon, Yong-Sun; Palmer, Kenneth E; Mason, Hugh S

2003-02-20

Bean yellow dwarf virus (BeYDV) is a monopartite geminivirus that can infect dicotyledonous plants. We have developed a high-level expression system that utilizes elements of the replication machinery of this single-stranded DNA virus. The replication initiator protein (Rep) mediates release and replication of a replicon from a DNA construct ("LSL vector") that contains an expression cassette for a gene of interest flanked by cis-acting elements of the virus. We used tobacco NT1 cells and biolistic delivery of plasmid DNA for evaluation of replication and expression of reporter genes contained within an LSL vector. By codelivery of a GUS reporter-LSL vector and a Rep-supplying vector, we obtained up to 40-fold increase in expression levels compared to delivery of the reporter-LSL vectors alone. High-copy replication of the LSL vector was correlated with enhanced expression of GUS. Rep expression using a whole BeYDV clone, a cauliflower mosaic virus 35S promoter driving either genomic rep or an intron-deleted rep gene, or 35S-rep contained in the LSL vector all achieved efficient replication and enhancement of GUS expression. We anticipate that this system can be adapted for use in transgenic plants or plant cell cultures with appropriately regulated expression of Rep, with the potential to greatly increase yield of recombinant proteins. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 430-437, 2003.

Immunogenicity and protective efficacy of recombinant Modified Vaccinia virus Ankara candidate vaccines delivering West Nile virus envelope antigens

NARCIS (Netherlands)

Volz, Asisa; Lim, Stephanie; Kaserer, Martina; Pijlman, Gorben P.

2016-01-01

West Nile virus (WNV) cycles between insects and wild birds, and is transmitted via mosquito vectors to horses and humans, potentially causing severe neuroinvasive disease. Modified Vaccinia virus Ankara (MVA) is an advanced viral vector for developing new recombinant vaccines against infectious

Vaccine efficacy against malaria by the combination of porcine parvovirus-like particles and vaccinia virus vectors expressing CS of Plasmodium.

Directory of Open Access Journals (Sweden)

Dolores Rodríguez

Full Text Available With the aim to develop an efficient and cost-effective approach to control malaria, we have generated porcine parvovirus-like particles (PPV-VLPs carrying the CD8(+ T cell epitope (SYVPSAEQI of the circumsporozoite (CS protein from Plasmodium yoelii fused to the PPV VP2 capsid protein (PPV-PYCS, and tested in prime/boost protocols with poxvirus vectors for efficacy in a rodent malaria model. As a proof-of concept, we have characterized the anti-CS CD8(+ T cell response elicited by these hybrid PPV-VLPs in BALB/c mice after immunizations with the protein PPV-PYCS administered alone or in combination with recombinant vaccinia virus (VACV vectors from the Western Reserve (WR and modified virus Ankara (MVA strains expressing the entire P. yoelii CS protein. The results of different immunization protocols showed that the combination of PPV-PYCS prime/poxvirus boost was highly immunogenic, inducing specific CD8+ T cell responses to CS resulting in 95% reduction in liver stage parasites two days following sporozoite challenge. In contrast, neither the administration of PPV-PYCS alone nor the immunization with the vectors given in the order poxvirus/VLPs was as effective. The immune profile induced by VLPs/MVA boost was associated with polyfunctional and effector memory CD8+ T cell responses. These findings highlight the use of recombinant parvovirus PPV-PYCS particles as priming agents and poxvirus vectors, like MVA, as booster to enhance specific CD8+ T cell responses to Plasmodium antigens and to control infection. These observations are relevant in the design of T cell-inducing vaccines against malaria.

Zika and its vector mosquitoes in Mexico

Directory of Open Access Journals (Sweden)

Luis del Carpio-Orantes

2018-06-01

Full Text Available In the present study, we carried out a review on the potential vectors of the Zika virus in the Americas, specifically in Mexico. Being vectors of the Culicidae family, they have great predominance in those territories, which could facilitate viral dissemination.

Latency and Persistence of 'Candidatus Liberibacter asiaticus' in Its Psyllid Vector, Diaphorina citri (Hemiptera: Liviidae).

Science.gov (United States)

Canale, Maria Cristina; Tomaseto, Arthur Fernando; Haddad, Marineia de Lara; Della Coletta-Filho, Helvécio; Lopes, João Roberto Spotti

2017-03-01

Although 'Candidatus Liberibacter asiaticus' (Las) is a major pathogen associated with citrus huanglongbing (HLB), some characteristics of transmission by the psyllid vector Diaphorina citri are not fully understood. We examined the latent period and persistence of transmission of Las by D. citri in a series of experiments at 25°C, in which third-instar psyllid nymphs and 1-week-old adults were confined on infected citrus for an acquisition access period (AAP), and submitted to sequential inoculation access periods (IAPs) on healthy citrus seedlings. The median latent period (LP 50 , i.e., acquisition time after which 50% of the individuals can inoculate) of 16.8 and 17.8 days for psyllids that acquired Las as nymphs and adults, respectively, was determined by transferring single individuals in 48-h IAPs. Inoculation events were intermittent and randomly distributed over the IAPs, but were more frequent after acquisition by nymphs. A minimum latent period of 7 to 10 days was observed by transferring groups of 10 psyllids in 48-h IAPs, after a 96-h AAP by nymphs. Psyllids transmitted for up to 5 weeks, when submitted to sequential 1-week IAPs after a 14-day AAP as nymphs. The long latent period and persistence of transmission are indirect evidences of circulative propagation of Las in D. citri.

RNA Interference in Insect Vectors for Plant Viruses

OpenAIRE

Kanakala, Surapathrudu; Ghanim, Murad

2016-01-01

Insects and other arthropods are the most important vectors of plant pathogens. The majority of plant pathogens are disseminated by arthropod vectors such as aphids, beetles, leafhoppers, planthoppers, thrips and whiteflies. Transmission of plant pathogens and the challenges in managing insect vectors due to insecticide resistance are factors that contribute to major food losses in agriculture. RNA interference (RNAi) was recently suggested as a promising strategy for controlling insect pests...

Activity of aphids associated with lettuce and broccoli in Spain and their efficiency as vectors of Lettuce mosaic virus.

Science.gov (United States)

Nebreda, M; Moreno, A; Pérez, N; Palacios, I; Seco-Fernández, V; Fereres, A

2004-03-01

This research sought to identify the aphid virus vector species associated with lettuce and broccoli crops in Spain, and to determine their population dynamics and ability to transmit Lettuce mosaic virus (LMV). Green tile traps and Moericke yellow water-pan traps were used to monitor aphid flights during the spring and autumn growing seasons of 2001. Aphid species feeding on lettuce were counted weekly. The transmission efficiencies of LMV were determined for the aphid species caught most frequently. The Moericke traps generally caught more aphid species than the tile trap, but the latter was the most suitable to estimate flight activity of species involved in virus spread. Spring aphid catches indicated that the main aphid species landing on lettuce in the regions of Madrid and Murcia was Hyperomyzus lactucae, but Brachycaudus helichrysi was also abundant in both regions. In broccoli in the Navarra region, the most abundant species in spring were Aphis fabae, B. helichrysi and H. lactucae. In autumn-sown crops, the main species landing on lettuce in the Madrid region were Hyadaphis coriandri and Aphis spiraecola. In Murcia, A. spiraecola and Myzus persicae were the most abundant, while in Navarra, Therioaphis trifolii, and various Aphis spp. were the most numerous landing on broccoli. The main aphid species colonising lettuce was Nasonovia ribisnigri, but other less abundant colonising species were Aulacorthum solani and Macrosiphum euphorbiae. The most efficient vectors of LMV were M. persicae, Aphis gossypii and M. euphorbiae, while A. fabae and H. lactucae transmitted with low efficiency, and Rhopalosiphum padi and N. ribisnigri did not transmit. Occurrence of LMV epidemics in central Spain in relation to aphid flights and the role of weeds as virus reservoirs is discussed.

The Polerovirus Minor Capsid Protein Determines Vector Specificity and Intestinal Tropism in the Aphid

Science.gov (United States)

Brault, Véronique; Périgon, Sophie; Reinbold, Catherine; Erdinger, Monique; Scheidecker, Danièle; Herrbach, Etienne; Richards, Ken; Ziegler-Graff, Véronique

2005-01-01

Aphid transmission of poleroviruses is highly specific, but the viral determinants governing this specificity are unknown. We used a gene exchange strategy between two poleroviruses with different vectors, Beet western yellows virus (BWYV) and Cucurbit aphid-borne yellows virus (CABYV), to analyze the role of the major and minor capsid proteins in vector specificity. Virus recombinants obtained by exchanging the sequence of the readthrough domain (RTD) between the two viruses replicated in plant protoplasts and in whole plants. The hybrid readthrough protein of chimeric viruses was incorporated into virions. Aphid transmission experiments using infected plants or purified virions revealed that vector specificity is driven by the nature of the RTD. BWYV and CABYV have specific intestinal sites in the vectors for endocytosis: the midgut for BWYV and both midgut and hindgut for CABYV. Localization of hybrid virions in aphids by transmission electron microscopy revealed that gut tropism is also determined by the viral origin of the RTD. PMID:16014930

Impact of West Nile virus dose and incubation period on vector competence of Culex nigripalpus (Diptera: Culicidae).

Science.gov (United States)

Richards, Stephanie L; Anderson, Sheri L; Lord, Cynthia C; Tabachnick, Walter J

2011-11-01

Female Culex nigripalpus were fed blood containing a low dose (6.3±0.01 logs plaque-forming units (PFU)/mL) or high dose (7.3±0.1 logs PFU/mL) of West Nile virus (WNV) and maintained at 28°C for incubation periods (IPs) of 6 or 12 days. Vector competence was measured using rates of infection (% with WNV-positive bodies), dissemination (% infected with WNV-positive legs), and transmission (% infected with WNV-positive saliva). Infection rates were not influenced by dose or IP. Dissemination rates were significantly higher at the high dose, and this was dependent on IP. Despite 100% infection and 90% dissemination in the most permissive treatment of high dose and 12 days, only 11% transmission was observed. Virus titers in body and leg tissues were significantly lower at the low dose and the titers were not influenced by IP. We show that not all mosquitoes with infections and/or disseminated infections transmit WNV under the conditions of this test. Therefore, characterizing the transmission ability of a vector population using infection or dissemination as indicators of transmission may provide inaccurate information. The complex relationships between infection, dissemination, and transmission must be evaluated under a variety of biological and environmental conditions to begin to assess the epidemiological risk of natural mosquito populations.

Statistical Inference for Porous Materials using Persistent Homology.

Energy Technology Data Exchange (ETDEWEB)

Moon, Chul [Univ. of Georgia, Athens, GA (United States); Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, Scott A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-12-01

We propose a porous materials analysis pipeline using persistent homology. We rst compute persistent homology of binarized 3D images of sampled material subvolumes. For each image we compute sets of homology intervals, which are represented as summary graphics called persistence diagrams. We convert persistence diagrams into image vectors in order to analyze the similarity of the homology of the material images using the mature tools for image analysis. Each image is treated as a vector and we compute its principal components to extract features. We t a statistical model using the loadings of principal components to estimate material porosity, permeability, anisotropy, and tortuosity. We also propose an adaptive version of the structural similarity index (SSIM), a similarity metric for images, as a measure to determine the statistical representative elementary volumes (sREV) for persistence homology. Thus we provide a capability for making a statistical inference of the uid ow and transport properties of porous materials based on their geometry and connectivity.

Recombinant Newcastle disease viral vector expressing hemagglutinin or fusion of canine distemper virus is safe and immunogenic in minks.

Science.gov (United States)

Ge, Jinying; Wang, Xijun; Tian, Meijie; Gao, Yuwei; Wen, Zhiyuan; Yu, Guimei; Zhou, Weiwei; Zu, Shulong; Bu, Zhigao

2015-05-15

Canine Distemper Virus (CDV) infects many carnivores and cause several high-mortality disease outbreaks. The current CDV live vaccine cannot be safely used in some exotic species, such as mink and ferret. Here, we generated recombinant lentogenic Newcastle disease virus (NDV) LaSota expressing either envelope glycoproyein, heamagglutinine (H) or fusion protein (F), named as rLa-CDVH and rLa-CDVF, respectively. The feasibility of these recombinant NDVs to serve as live virus-vectored CD vaccine was evaluated in minks. rLa-CDVH induced significant neutralization antibodies (NA) to CDV and provided solid protection against virulent CDV challenge. On the contrast, rLa-CDVF induced much lower NA to CDV and fail to protected mink from virulent CDV challenge. Results suggest that recombinant NDV expressing CDV H is safe and efficient candidate vaccine against CDV in mink, and maybe other host species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Infectious Maize rayado fino virus from Cloned cDNA.

Science.gov (United States)

Edwards, Michael C; Weiland, John J; Todd, Jane; Stewart, Lucy R

2015-06-01

A full-length cDNA clone was produced from a U.S. isolate of Maize rayado fino virus (MRFV), the type member of the genus Marafivirus within the family Tymoviridae. Infectivity of transcripts derived from cDNA clones was demonstrated by infection of maize plants and protoplasts, as well as by transmission via the known leafhopper vectors Dalbulus maidis and Graminella nigrifrons that transmit the virus in a persistent-propagative manner. Infection of maize plants through vascular puncture inoculation of seed with transcript RNA resulted in the induction of fine stipple stripe symptoms typical of those produced by wild-type MRFV and a frequency of infection comparable with that of the wild type. Northern and Western blotting confirmed the production of MRFV-specific RNAs and proteins in infected plants and protoplasts. An unanticipated increase in subgenomic RNA synthesis over levels in infected plants was observed in protoplasts infected with either wild-type or cloned virus. A conserved cleavage site motif previously demonstrated to function in both Oat blue dwarf virus capsid protein and tymoviral nonstructural protein processing was identified near the amino terminus of the MRFV replicase polyprotein, suggesting that cleavage at this site also may occur.

Zoonotic aspects of vector-borne infections.

Science.gov (United States)

Failloux, A-B; Moutailler, S

2015-04-01

Vector-borne diseases are principally zoonotic diseases transmitted to humans by animals. Pathogens such as bacteria, parasites and viruses are primarily maintained within an enzootic cycle between populations of non-human primates or other mammals and largely non-anthropophilic vectors. This 'wild' cycle sometimes spills over in the form of occasional infections of humans and domestic animals. Lifestyle changes, incursions by humans into natural habitats and changes in agropastoral practices create opportunities that make the borders between wildlife and humans more permeable. Some vector-borne diseases have dispensed with the need for amplification in wild or domestic animals and they can now be directly transmitted to humans. This applies to some viruses (dengue and chikungunya) that have caused major epidemics. Bacteria of the genus Bartonella have reduced their transmission cycle to the minimum, with humans acting as reservoir, amplifier and disseminator. The design of control strategies for vector-borne diseases should be guided by research into emergence mechanisms in order to understand how a wild cycle can produce a pathogen that goes on to cause devastating urban epidemics.

Detection and identification of Rift Valley fever virus in mosquito vectors by quantitative real-time PCR.

Science.gov (United States)

Mwaengo, D; Lorenzo, G; Iglesias, J; Warigia, M; Sang, R; Bishop, R P; Brun, A

2012-10-01

Diagnostic methods allowing for rapid identification of pathogens are crucial for controlling and preventing dissemination after disease outbreaks as well as for use in surveillance programs. For arboviruses, detection of the presence of virus in their arthropod hosts is important for monitoring of viral activity and quantitative information is useful for modeling of transmission dynamics. In this study, molecular detection of Rift Valley fever virus (RVFV) in mosquito samples from the 2006 to 2007 East African outbreaks was performed using quantitative real-time PCR assay (qRT-PCR). Specific RVFV sequence-based primer/fluorogenic (TaqMan) probe sets were derived from the L and S RNA segments of the virus. Both primer-probe L and S segment-based combinations detected genomic RVFV sequences, with generally comparable levels of sensitivity. Viral loads from three mosquito species, Aedes mcintoshi, Aedes ochraceus and Mansonia uniformis were estimated and significant differences of between 5- and 1000-fold were detected between Ae. mcintoshi and M. uniformis using both the L and S primer-probe-based assays. The genetic relationships of the viral sequences in mosquito samples were established by partial M segment sequencing and assigned to the two previously described viral lineages defined by analysis of livestock isolates obtained during the 2006-2007 outbreak, confirming that similar viruses were present in both the vector and mammalian host. The data confirms the utility of qRT-PCR for identification and initial quantification of virus in mosquito samples during RVFV outbreaks. Copyright © 2012 Elsevier B.V. All rights reserved.

Viral Vectors for Use in the Development of Biodefense Vaccines

National Research Council Canada - National Science Library

Lee, John S; Hadjipanayis, Angela G; Parker, Michael D

2005-01-01

.... DNA vectors, live-attenuated viruses and bacteria, recombinant proteins combined with adjuvant, and viral- or bacterial-vectored vaccines have been developed as countermeasures against many potential...

Inter-epidemic abundance and distribution of potential mosquito vectors for Rift Valley fever virus in Ngorongoro district, Tanzania

OpenAIRE

Mweya, Clement N.; Kimera, Sharadhuli I.; Mellau, Lesakit S. B.; Mboera, Leonard E. G.

2015-01-01

Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that primarily affects ruminants but also has the capacity to infect humans. Objective: To determine the abundance and distribution of mosquito vectors in relation to their potential role in the virus transmission and maintenance in disease epidemic areas of Ngorongoro district in northern Tanzania. Methods: A cross-sectional entomological investigation was carried out before the suspected RVF outbreak in October 2012. Mos...

B cell follicle sanctuary permits persistent productive simian immunodeficiency virus infection in elite controllers.

Science.gov (United States)

Fukazawa, Yoshinori; Lum, Richard; Okoye, Afam A; Park, Haesun; Matsuda, Kenta; Bae, Jin Young; Hagen, Shoko I; Shoemaker, Rebecca; Deleage, Claire; Lucero, Carissa; Morcock, David; Swanson, Tonya; Legasse, Alfred W; Axthelm, Michael K; Hesselgesser, Joseph; Geleziunas, Romas; Hirsch, Vanessa M; Edlefsen, Paul T; Piatak, Michael; Estes, Jacob D; Lifson, Jeffrey D; Picker, Louis J

2015-02-01

Chronic-phase HIV and simian immunodeficiency virus (SIV) replication is reduced by as much as 10,000-fold in elite controllers (ECs) compared with typical progressors (TPs), but sufficient viral replication persists in EC tissues to allow viral sequence evolution and induce excess immune activation. Here we show that productive SIV infection in rhesus monkey ECs, but not TPs, is markedly restricted to CD4(+) follicular helper T (TFH) cells, suggesting that these EC monkeys' highly effective SIV-specific CD8(+) T cells can effectively clear productive SIV infection from extrafollicular sites, but their relative exclusion from B cell follicles prevents their elimination of productively infected TFH cells. CD8(+) lymphocyte depletion in EC monkeys resulted in a dramatic re-distribution of productive SIV infection to non-TFH cells, with restriction of productive infection to TFH cells resuming upon CD8(+) T cell recovery. Thus, B cell follicles constitute 'sanctuaries' for persistent SIV replication in the presence of potent anti-viral CD8(+) T cell responses, potentially complicating efforts to cure HIV infection with therapeutic vaccination or T cell immunotherapy.

Characterization of thymus-associated lymphoid depletion in bovine calves acutely or persistently infected with bovine viral diarrhea virus 1, bovine viral diarrhea virus 2 or HoBi-like pestivirus.

Science.gov (United States)

Falkenberg, Shollie M; Bauermann, Fernando V; Ridpath, Julia F

2017-11-01

Naïve pregnant cattle exposed to pestiviruses between 40-125 days of gestation can give birth to persistently infected (PI) calves. Clinical presentation and survivability, in PI cattle, is highly variable even with the same pestivirus strain whereas the clinical presentation in acute infections is more uniform with severity of symptoms being primarily a function of virulence of the infecting virus. The aim of this study was to compare thymic depletion, as measured by comparing the area of the thymic cortex to the medulla (corticomedullary ratio), in acute and persistent infections of the same pestivirus isolate. The same general trends were observed with each pestivirus isolate. Thymic depletion was observed in both acutely and persistently infected calves. The average thymic depletion observed in acutely infected calves was greater than that in age matched PI calves. PI calves, regardless of infecting virus, revealed a greater variability in amount of depletion compared to acutely infected calves. A trend was observed between survivability and depletion of the thymus, with PI calves surviving less than 5 weeks having lower corticomedullary ratios and greater depletion. This is the first study to compare PI and acutely infected calves with the same isolates as well as to evaluate PI calves based on survivability. Further, this study identified a quantifiable phenotype associated with potential survivability.

Clinical isolates of GB virus type C vary in their ability to persist and replicate in peripheral blood mononuclear cell cultures

International Nuclear Information System (INIS)

George, Sarah L.; Xiang Jinhua; Stapleton, Jack T.

2003-01-01

GB virus C/hepatitis G virus (GBV-C) replication in vitro is inefficient and inconsistent. In this study, clinical isolates of GBV-C were evaluated using peripheral blood mononuclear cell (PBMC) based culture methods. Isolates varied consistently in their ability to persistently replicate, and yield increased in cells grown without PHA/IL-2 stimulation. The deduced polyprotein sequence of an isolate that replicated well was determined (GenBank AY196904) and compared to 20 full-length GBV-C sequences. Fourteen of the 16 unique amino acid polymorphisms identified were in the coding regions for nonstructural proteins associated with interferon resistance and RNA replication. These data indicate that clinical GBV-C isolates vary in their ability to persist in culture, do not require PHA/IL-2 stimulation, and that sequence variability in key regulatory regions may affect growth in PBMC cultures. Since GBV-C appears to inhibit HIV replication in a coinfection model, these studies should facilitate determination of the mechanism of this interaction

Abundance and distribution of sylvatic dengue virus vectors in three different land cover types in Sarawak, Malaysian Borneo.

Science.gov (United States)

Young, Katherine I; Mundis, Stephanie; Widen, Steven G; Wood, Thomas G; Tesh, Robert B; Cardosa, Jane; Vasilakis, Nikos; Perera, David; Hanley, Kathryn A

2017-08-31

Mosquito-borne dengue virus (DENV) is maintained in a sylvatic, enzootic cycle of transmission between canopy-dwelling non-human primates and Aedes mosquitoes in Borneo. Sylvatic DENV can spill over into humans living in proximity to forest foci of transmission, in some cases resulting in severe dengue disease. The most likely vectors of such spillover (bridge vectors) in Borneo are Ae. albopictus and Ae. niveus. Borneo is currently experiencing extensive forest clearance. To gauge the effect of this change in forest cover on the likelihood of sylvatic DENV spillover, it is first necessary to characterize the distribution of bridge vectors in different land cover types. In the current study, we hypothesized that Ae. niveus and Ae. albopictus would show significantly different distributions in different land cover types; specifically, we predicted that Ae. niveus would be most abundant in forests whereas Ae. albopictus would have a more even distribution in the landscape. Mosquitoes were collected from a total of 15 sites using gravid traps and a backpack aspirator around Kampong Puruh Karu, Sarawak, Malaysian Borneo, where sylvatic DENV spillover has been documented. A total of 2447 mosquitoes comprising 10 genera and 4 species of Aedes, were collected over the three years, 2013, 2014 and 2016, in the three major land cover types in the area, homestead, agriculture and forest. Mosquitoes were identified morphologically, pooled by species and gender, homogenized, and subject to DNA barcoding of each Aedes species and to arbovirus screening. As predicted, Ae. niveus was found almost exclusively in forests whereas Ae. albopictus was collected in all land cover types. Aedes albopictus was significantly (P = 0.04) more abundant in agricultural fields than forests. Sylvatic DENV was not detected in any Aedes mosquito pools, however genomes of 14 viruses were detected using next generation sequencing. Land cover type affects the abundance and distribution of the most

Persistence of highly pathogenic avian influenza H5N1 virus defined by agro-ecological niche

Science.gov (United States)

Hogerwerf, Lenny; Wallace, Rob G.; Ottaviani, Daniela; Slingenbergh, Jan; Prosser, Diann; Bergmann, Luc; Gilbert, Marius

2010-01-01

The highly pathogenic avian influenza (HPAI) H5N1 virus has spread across Eurasia and into Africa. Its persistence in a number of countries continues to disrupt poultry production, impairs smallholder livelihoods, and raises the risk a genotype adapted to human-to-human transmission may emerge. While previous studies identified domestic duck reservoirs as a primary risk factor associated with HPAI H5N1 persistence in poultry in Southeast Asia, little is known of such factors in countries with different agro-ecological conditions, and no study has investigated the impact of such conditions on HPAI H5N1 epidemiology at the global scale. This study explores the patterns of HPAI H5N1 persistence worldwide, and for China, Indonesia, and India includes individual provinces that have reported HPAI H5N1 presence during the 2004–2008 period. Multivariate analysis of a set of 14 agricultural, environmental, climatic, and socio-economic factors demonstrates in quantitative terms that a combination of six variables discriminates the areas with human cases and persistence: agricultural population density, duck density, duck by chicken density, chicken density, the product of agricultural population density and chicken output/input ratio, and purchasing power per capita. The analysis identifies five agro-ecological clusters, or niches, representing varying degrees of disease persistence. The agro-ecological distances of all study areas to the medoid of the niche with the greatest number of human cases are used to map HPAI H5N1 risk globally. The results indicate that few countries remain where HPAI H5N1 would likely persist should it be introduced.

Vector competence of Culicoides bolitinos and C. imicola for South African bluetongue virus serotypes 1, 3 and 4.

Science.gov (United States)

Venter, G J; Paweska, J T; Van Dijk, A A; Mellor, P S; Tabachnick, W J

1998-10-01

The susceptibility of field-collected Culicoides bolitinos to infection by oral ingestion of bluetongue virus serotypes 1, 3 and 4 (BLU 1, 3 and 4) was compared with that of field-collected C. imicola and laboratory reared C. variipennis sonorensis. The concentration of the virus per millilitre of bloodmeal was 10(5.0) and 10(6.0)TCID50 for BLU 4 and 10(7.2)TCID50 for BLU 1 and 3. Of 4927 C. bolitinos and 9585 C. imicola fed, 386 and 287 individual midges survived 10 days extrinsic incubation, respectively. Midges were assayed for the presence of virus using a microtitration assay on BHK-21 cells and/or an antigen capture ELISA. Infection prevalences for the different serotypes as determined by virus isolation ranged from 22.7 to 82.0% in C. bolitinos and from 1.9 to 9.8% in C. imicola; infection prevalences were highest for BLU 1, and lowest for BLU 4 in both species. The mean log10 TCID50 titre of the three BLU viruses per single fly was higher in C. bolitinos than in C. imicola. The results suggested that C. bolitinos populations are capable vectors of the BLU viruses in South Africa. A high correlation was found between virus isolation and ELISA results for the detection of BLU 1, and less for BLU 4; the ELISA failed to detect the presence of BLU 3 in infected flies. The C. v. sonorensis colonies had a significantly lower susceptibility to infection with BLU 1, 3 and 4 than C. bolitinos and C. imicola. However, since infection prevalence of C. v. sonorensis was determined only by ELISA, this finding may merely reflect the insensitivity of this assay at low virus titres, compared to virus isolation.

Disruption of Ethylene Responses by Turnip mosaic virus Mediates Suppression of Plant Defense against the Green Peach Aphid Vector.

Science.gov (United States)

Casteel, Clare L; De Alwis, Manori; Bak, Aurélie; Dong, Haili; Whitham, Steven A; Jander, Georg

2015-09-01

Plants employ diverse responses mediated by phytohormones to defend themselves against pathogens and herbivores. Adapted pathogens and herbivores often manipulate these responses to their benefit. Previously, we demonstrated that Turnip mosaic virus (TuMV) infection suppresses callose deposition, an important plant defense induced in response to feeding by its aphid vector, the green peach aphid (Myzus persicae), and increases aphid fecundity compared with uninfected control plants. Further, we determined that production of a single TuMV protein, Nuclear Inclusion a-Protease (NIa-Pro) domain, was responsible for changes in host plant physiology and increased green peach aphid reproduction. To characterize the underlying molecular mechanisms of this phenomenon, we examined the role of three phytohormone signaling pathways, jasmonic acid, salicylic acid, and ethylene (ET), in TuMV-infected Arabidopsis (Arabidopsis thaliana), with or without aphid herbivory. Experiments with Arabidopsis mutants ethylene insensitive2 and ethylene response1, and chemical inhibitors of ET synthesis and perception (aminoethoxyvinyl-glycine and 1-methylcyclopropene, respectively), show that the ET signaling pathway is required for TuMV-mediated suppression of Arabidopsis resistance to the green peach aphid. Additionally, transgenic expression of NIa-Pro in Arabidopsis alters ET responses and suppresses aphid-induced callose formation in an ET-dependent manner. Thus, disruption of ET responses in plants is an additional function of NIa-Pro, a highly conserved potyvirus protein. Virus-induced changes in ET responses may mediate vector-plant interactions more broadly and thus represent a conserved mechanism for increasing transmission by insect vectors across generations. © 2015 American Society of Plant Biologists. All Rights Reserved.

Vector competence of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) for the DEN2-FJ10 and DEN2-FJ11 strains of the dengue 2 virus in Fujian, China.

Science.gov (United States)

Guo, Xiao-Xia; Li, Chun-Xiao; Zhang, Ying-Mei; Xing, Dan; Dong, Yan-De; Zhang, Heng-Duan; Qin, Cheng-Feng; Zhao, Tong-Yan

2016-09-01

Dengue is an acute, emerging, infectious disease transmitted by Aedes mosquitoes that has become a serious global public health problem. The DEN2-FJ10 and DEN2-FJ11 strains of the dengue 2 virus were originally isolated from the serum of a patient with dengue fever in Fujian Province, China, in 1999. Our data provide the first assessment of the vector competence of Aedes mosquitoes with respect to the DEN2-FJ10 and DEN2-FJ11 strains of the dengue virus. There were significant differences in the replication rates of these two viral strains in Aedes albopictus and Aedes aegypti (P0.05). In summary, our results indicate that Ae. albopictus and Ae. aegypti mosquitoes are moderately competent vectors of the DEN2-FJ10 and DEN2-FJ11 strains of the dengue virus and provide the first evidence of the effect of these two viral strains on the vector competence of mosquitoes in China. Copyright © 2016 Elsevier B.V. All rights reserved.

Ecological Fitness of Non-vector Planthopper Sogatella furcifera on Rice Plants Infected with Rice Black Streaked Dwarf Virus

Directory of Open Access Journals (Sweden)

Xiao-chan HE

2012-12-01

Full Text Available We evaluated the effects of rice black streak dwarf virus (RBSDV-infested rice plants on the ecological parameters and its relevant defensive and detoxification enzymes of white-backed planthopper (WBPH in laboratory for exploring the relationship between RBSDV and the non-vector planthopper. The results showed that nymph survival rate, female adult weight and fecundity, and egg hatchability of WBPH fed on RBSDV-infested rice plants did not markedly differ from those on healthy plants, whereas the female adult longevity and egg duration significantly shortened on diseased plants. Furthermore, significantly higher activities of defensive enzymes (dismutase, catalase and peroxidase and detoxification enzymes (acetylcholinesterase, carboxylesterase and glutathione S-transferase were found in WBPH adults fed on infected plants. Results implied that infestation by RBSDV increased the ecological fitness of non-vector planthopper population.

Landscape Genetics of Aedes mcintoshi (Diptera: Culicidae), an Important Vector of Rift Valley Fever Virus in Northeastern Kenya.

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Campbell, Lindsay P; Alexander, Alana M

2017-09-01

Rift Valley fever virus (RVFV) is a vector-borne, zoonotic disease that affects humans, wild ungulates, and domesticated livestock in Africa and the Arabian Peninsula. Rift Valley fever virus exhibits interepizootic and epizootic phases, the latter defined by widespread virus occurrence in domesticated livestock. Kenya appears to be particularly vulnerable to epizootics, with 11 outbreaks occurring between 1951 and 2007. The mosquito species Aedes mcintoshi (subgenus Neomelaniconion) is an important primary vector for RVFV in Kenya. Here, we investigate associations between genetic diversity and differentiation of one regional subclade of Ae. mcintoshi in Northeastern Kenya with environmental variables, using a multivariate statistical approach. Using CO1 (cytochrome oxidase subunit 1) sequence data deposited in GenBank, we found no evidence of isolation by distance contributing to genetic differentiation across the study area. However, we did find significant CO1 subpopulation structure and associations with recent mean precipitation values. In addition, variation in genetic diversity across our seven sample sites was associated with both precipitation and percentage clay in the soil. The large number of haplotypes found in this data set indicates that a great deal of diversity remains unsampled in this region. Additional sampling across a larger geographic area, combined with next-generation sequencing approaches that better characterize the genome, would provide a more robust assessment of genetic diversity and differentiation. Further understanding of the genetic structure of Ae. mcintoshi could provide useful information regarding the potential for RVFV to spread across East African landscapes. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Transmission potential of Zika virus infection in the South Pacific

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Hiroshi Nishiura

2016-04-01

Conclusions: The transmissibility of Zika virus infection appears to be comparable to those of dengue and chikungunya viruses. Considering that Aedes species are a shared vector, this finding indicates that Zika virus replication within the vector is perhaps comparable to dengue and chikungunya.

Pseudotyped Lentiviral Vectors for Retrograde Gene Delivery into Target Brain Regions

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Kenta Kobayashi

2017-08-01

Full Text Available Gene transfer through retrograde axonal transport of viral vectors offers a substantial advantage for analyzing roles of specific neuronal pathways or cell types forming complex neural networks. This genetic approach may also be useful in gene therapy trials by enabling delivery of transgenes into a target brain region distant from the injection site of the vectors. Pseudotyping of a lentiviral vector based on human immunodeficiency virus type 1 (HIV-1 with various fusion envelope glycoproteins composed of different combinations of rabies virus glycoprotein (RV-G and vesicular stomatitis virus glycoprotein (VSV-G enhances the efficiency of retrograde gene transfer in both rodent and nonhuman primate brains. The most recently developed lentiviral vector is a pseudotype with fusion glycoprotein type E (FuG-E, which demonstrates highly efficient retrograde gene transfer in the brain. The FuG-E–pseudotyped vector permits powerful experimental strategies for more precisely investigating the mechanisms underlying various brain functions. It also contributes to the development of new gene therapy approaches for neurodegenerative disorders, such as Parkinson’s disease, by delivering genes required for survival and protection into specific neuronal populations. In this review article, we report the properties of the FuG-E–pseudotyped vector, and we describe the application of the vector to neural circuit analysis and the potential use of the FuG-E vector in gene therapy for Parkinson’s disease.

Immunogenicity of seven new recombinant yellow fever viruses 17D expressing fragments of SIVmac239 Gag, Nef, and Vif in Indian rhesus macaques.

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Mauricio A Martins

Full Text Available An effective vaccine remains the best solution to stop the spread of human immunodeficiency virus (HIV. Cellular immune responses have been repeatedly associated with control of viral replication and thus may be an important element of the immune response that must be evoked by an efficacious vaccine. Recombinant viral vectors can induce potent T-cell responses. Although several viral vectors have been developed to deliver HIV genes, only a few have been advanced for clinical trials. The live-attenuated yellow fever vaccine virus 17D (YF17D has many properties that make it an attractive vector for AIDS vaccine regimens. YF17D is well tolerated in humans and vaccination induces robust T-cell responses that persist for years. Additionally, methods to manipulate the YF17D genome have been established, enabling the generation of recombinant (rYF17D vectors carrying genes from unrelated pathogens. Here, we report the generation of seven new rYF17D viruses expressing fragments of simian immunodeficiency virus (SIVmac239 Gag, Nef, and Vif. Studies in Indian rhesus macaques demonstrated that these live-attenuated vectors replicated in vivo, but only elicited low levels of SIV-specific cellular responses. Boosting with recombinant Adenovirus type-5 (rAd5 vectors resulted in robust expansion of SIV-specific CD8(+ T-cell responses, particularly those targeting Vif. Priming with rYF17D also increased the frequency of CD4(+ cellular responses in rYF17D/rAd5-immunized macaques compared to animals that received rAd5 only. The effect of the rYF17D prime on the breadth of SIV-specific T-cell responses was limited and we also found evidence that some rYF17D vectors were more effective than others at priming SIV-specific T-cell responses. Together, our data suggest that YF17D - a clinically relevant vaccine vector - can be used to prime AIDS virus-specific T-cell responses in heterologous prime boost regimens. However, it will be important to optimize rYF17D

Persistence of phlebotomine Leishmania vectors in urban sites of Catania (Sicily, Italy).

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Lisi, Oscar; D'Urso, Vera; Vaccalluzzo, Valerio; Bongiorno, Gioia; Khoury, Cristina; Severini, Francesco; Di Muccio, Trentina; Gramiccia, Marina; Gradoni, Luigi; Maroli, Michele

2014-12-09

Pioneering research on "Mediterranean Kala-Azar" carried out by Adler and Theodor early in the past century (~1930s) had identified Catania city (Sicily) as a major focus of the disease nowadays known as zoonotic visceral leishmaniasis (VL). Despite the fact that disease in both humans and dogs has continued to be highly prevalent in the Catania province up to the present times, research on Leishmania vectors in this urban focus dates back to that distant period. This study aimed to evaluate the persistence and current composition of the sand fly fauna in urban environments of Catania in recent years, 2006 and 2013. In 2006 fifty-one suitable collecting sites were identified within 44 sub-units of a grid drawn to include the urban Catania area. In 2013 the survey was restricted to four of the most productive and representative sites resulting from the 2006 survey. In both periods 3 collections per month were performed using standard sticky traps set for 3 days in wall holes/cavities along public roads, from the end of April through December. 43/51 sites (84.3%) were found positive for sand flies. The 2006 collections accounted for a total of 4341 specimens including six species. Among competent Leishmania vector species, P. perniciosus was the most prevalent (36.5%) being identified in all sand fly-positive sites, with significant abundance in those of the old city centre. Other species of interest were P. sergenti (2.5%) and P. neglectus (1.5%). The 2013 survey produced 1130 sand flies, of which 39.5% were P. perniciosus, 1.6% P. sergenti and 0.7% P. neglectus. A search for Leishmania DNA in a small sample of 72 P. perniciosus females revealed 11% infection prevalence. Our findings from an old urban focus of leishmaniasis demonstrate that phlebotomine sand flies have adapted fairly well to the drastic environmental changes that have occurred in cities of the Western world in the past century and still represent a potential risk for Leishmania transmission.

Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007

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Galal Fatma H

2010-03-01

Full Text Available Abstract Background Rift Valley fever (RVF is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Methods Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. Results A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7% in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2% in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ≥ 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between

Using remote sensing and machine learning for the spatial modelling of a bluetongue virus vector

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Van doninck, J.; Peters, J.; De Baets, B.; Ducheyne, E.; Verhoest, N. E. C.

2012-04-01

Bluetongue is a viral vector-borne disease transmitted between hosts, mostly cattle and small ruminants, by some species of Culicoides midges. Within the Mediterranean basin, C. imicola is the main vector of the bluetongue virus. The spatial distribution of this species is limited by a number of environmental factors, including temperature, soil properties and land cover. The identification of zones at risk of bluetongue outbreaks thus requires detailed information on these environmental factors, as well as appropriate epidemiological modelling techniques. We here give an overview of the environmental factors assumed to be constraining the spatial distribution of C. imicola, as identified in different studies. Subsequently, remote sensing products that can be used as proxies for these environmental constraints are presented. Remote sensing data are then used together with species occurrence data from the Spanish Bluetongue National Surveillance Programme to calibrate a supervised learning model, based on Random Forests, to model the probability of occurrence of the C. imicola midge. The model will then be applied for a pixel-based prediction over the Iberian peninsula using remote sensing products for habitat characterization.

Characterization of an internal ribosomal entry segment within the 5' leader of avian reticuloendotheliosis virus type A RNA and development of novel MLV-REV-based retroviral vectors.

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López-Lastra, M; Gabus, C; Darlix, J L

1997-11-01

The murine leukemia virus (MLV)-related type C viruses constitute a major class of retroviruses that includes numerous endogenous and exogenous mammalian viruses and the related avian spleen necrosis virus (SNV). The MLV-related viruses possess a long and multifunctional 5' untranslated leader involved in key steps of the viral life cycle--splicing, translation, RNA dimerization, encapsidation, and reverse transcription. Recent studies have shown that the 5' leader of Friend murine leukemia virus and Moloney murine leukemia virus can direct cap independent translation of gag precursor proteins (Berlioz et al., 1995; Vagner et al., 1995b). These data, together with structural homology studies (Koning et al., 1992), prompted us to undertake a search for new internal ribosome entry segment (IRES) of retroviral origin. Here we describe an IRES element within the 5' leader of avian reticuloendotheliosis virus type A (REV-A) genomic RNA. Data show that the REV-A 5' IRES element maps downstream of the packaging/dimerization (E/DLS) sequence (Watanabe and Temin, 1982; Darlix et al., 1992) and the minimal IRES sequence appears to be within a 129 nt fragment (nucleotides 452-580) of the 5' leader, immediately upstream of the gag AUG codon. The REV-A IRES has been successfully utilized in the construction of novel high titer MLV-based retroviral vectors, containing one or more IRES elements of retroviral origin. These retroviral constructs, which represent a starting point for the design of novel vectors suitable for gene therapy, are also of interest as a model system of internal translation initiation and its possible regulation during development, cancer, or virus infection.

Chikungunya Virus–Vector Interactions

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Lark L. Coffey

2014-11-01

Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

Virus vector-mediated genetic modification of brain tumor stromal cells after intravenous delivery.

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Volak, Adrienn; LeRoy, Stanley G; Natasan, Jeya Shree; Park, David J; Cheah, Pike See; Maus, Andreas; Fitzpatrick, Zachary; Hudry, Eloise; Pinkham, Kelsey; Gandhi, Sheetal; Hyman, Bradley T; Mu, Dakai; GuhaSarkar, Dwijit; Stemmer-Rachamimov, Anat O; Sena-Esteves, Miguel; Badr, Christian E; Maguire, Casey A

2018-05-16

The malignant primary brain tumor, glioblastoma (GBM) is generally incurable. New approaches are desperately needed. Adeno-associated virus (AAV) vector-mediated delivery of anti-tumor transgenes is a promising strategy, however direct injection leads to focal transgene spread in tumor and rapid tumor division dilutes out the extra-chromosomal AAV genome, limiting duration of transgene expression. Intravenous (IV) injection gives widespread distribution of AAV in normal brain, however poor transgene expression in tumor, and high expression in non-target cells which may lead to ineffective therapy and high toxicity, respectively. Delivery of transgenes encoding secreted, anti-tumor proteins to tumor stromal cells may provide a more stable and localized reservoir of therapy as they are more differentiated than fast-dividing tumor cells. Reactive astrocytes and tumor-associated macrophage/microglia (TAMs) are stromal cells that comprise a large portion of the tumor mass and are associated with tumorigenesis. In mouse models of GBM, we used IV delivery of exosome-associated AAV vectors driving green fluorescent protein expression by specific promoters (NF-κB-responsive promoter and a truncated glial fibrillary acidic protein promoter), to obtain targeted transduction of TAMs and reactive astrocytes, respectively, while avoiding transgene expression in the periphery. We used our approach to express the potent, yet toxic anti-tumor cytokine, interferon beta, in tumor stroma of a mouse model of GBM, and achieved a modest, yet significant enhancement in survival compared to controls. Noninvasive genetic modification of tumor microenvironment represents a promising approach for therapy against cancers. Additionally, the vectors described here may facilitate basic research in the study of tumor stromal cells in situ.

Acute hepatitis A virus infection is associated with a limited type I interferon response and persistence of intrahepatic viral RNA.

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Lanford, Robert E; Feng, Zongdi; Chavez, Deborah; Guerra, Bernadette; Brasky, Kathleen M; Zhou, Yan; Yamane, Daisuke; Perelson, Alan S; Walker, Christopher M; Lemon, Stanley M

2011-07-05

Hepatitis A virus (HAV) is an hepatotropic human picornavirus that is associated only with acute infection. Its pathogenesis is not well understood because there are few studies in animal models using modern methodologies. We characterized HAV infections in three chimpanzees, quantifying viral RNA by quantitative RT-PCR and examining critical aspects of the innate immune response including intrahepatic IFN-stimulated gene expression. We compared these infection profiles with similar studies of chimpanzees infected with hepatitis C virus (HCV), an hepatotropic flavivirus that frequently causes persistent infection. Surprisingly, HAV-infected animals exhibited very limited induction of type I IFN-stimulated genes in the liver compared with chimpanzees with acute resolving HCV infection, despite similar levels of viremia and 100-fold greater quantities of viral RNA in the liver. Minimal IFN-stimulated gene 15 and IFIT1 responses peaked 1-2 wk after HAV challenge and then subsided despite continuing high hepatic viral RNA. An acute inflammatory response at 3-4 wk correlated with the appearance of virus-specific antibodies and apoptosis and proliferation of hepatocytes. Despite this, HAV RNA persisted in the liver for months, remaining present long after clearance from serum and feces and revealing dramatic differences in the kinetics of clearance in the three compartments. Viral RNA was detected in the liver for significantly longer (35 to >48 wk) than HCV RNA in animals with acute resolving HCV infection (10-20 wk). Collectively, these findings indicate that HAV is far stealthier than HCV early in the course of acute resolving infection. HAV infections represent a distinctly different paradigm in virus-host interactions within the liver.

Culex quinquefasciatus (Diptera: Culicidae as a potential West Nile virus vector in Tucson, Arizona: Blood meal analysis indicates feeding on both humans and birds

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Margaret Zinser

2004-06-01

Full Text Available Most reports from the United States suggest Culex quinquefasciatus mosquitoes feed minimally on humans. Given the abundance of C. quinquefasciatus in residential Tucson and parts of metropolitan Phoenix, and the arrival of West Nile virus to this area, discovering the blood meal hosts of the local population is important. Using a sandwich ELISA technique, the local C. quinquefasciatus were found to feed on both humans and birds. This suggests they should be considered potential West Nile virus vectors.

Vectors of rickettsiae in Africa.

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