Search

Equine serum hepatitis (i.e., Theiler’s disease) is a serious and often life-threatening disease of unknown etiology that affects horses. A horse in Nebraska, USA, with serum hepatitis died 65 days after treatment with equine-origin tetanus antitoxin. We identified an unknown parvovirus in serum and liver of the dead horse and in the administered antitoxin. The equine parvovirus-hepatitis (EqPV-H) shares

Due to the risk of severe vaccine-associated adverse events, yellow fever vaccination in Brazil is only recommended in areas considered at risk for disease. From September 2008 through June 2009, two outbreaks of yellow fever in previously unvaccinated populations resulted in 21 confirmed cases with 9 deaths (case-fatality, 43%) in the southern state of Rio Grande do Sul and 28 cases with 11 deaths (39%) in Sao Paulo state. Epizootic deaths of non-human primates were reported before and during the outbreak. Over 5.5 million doses of yellow fever vaccine were administered in the two most affected states. Vaccine-associated adverse events were associated with six deaths due to acute viscerotropic disease (0.8 deaths per million doses administered) and 45 cases of acute neurotropic disease (5.6 per million doses administered). Yellow fever vaccine recommendations were revised to include areas in Brazil previously not considered at risk for yellow fever. [ABSTRACT FROM AUTHOR]

The alterations of MicroRNAs(miRNAs) in host cell after foot-and-mouth disease virus (FMDV) infection is still obscure. To increase our understanding of the pathogenesis of FMDV at the post-transcriptional regulation level, Solexa high-throu MicroRNAs (miRNAs) play an important role both in the post-transcriptional regulation of gene expression and host-virus interactions. Despite investigations of miRNA expression ghput sequencing and bioinformatic tools were used to identify differentially expressed miRNAs and analyze their functions during FMDV infection of PK-15cells. Results indicated that 9,165,674 and 9,230,378 clean reads were obtained, with 172 known and 72 novel miRNAs differently expressed in infected and uninfected groups respectively. Some of differently expressed miRNAs were validated using stem-loop real-time quantitative RT-PCR. The GO annotation and KEGG pathway analysis for target genes revealed that differently expressed miRNAs were involved in immune response and cell death pathways. [ABSTRACT FROM AUTHOR]

Wild aquatic birds are recognized as the natural reservoir of avian influenza A viruses (AIV), but across high and low pathogenic AIV strains, scientists have yet to rigorously identify most competent hosts for the various subtypes. We examined 11,870 GenBank records to provide a baseline inventory and insight into patterns of global AIV subtype diversity and richness. Further, we conducted an extensive literature review and communicated directly with scientists to accumulate data from 50 non-overlapping studies and over 250,000 birds to assess the status of historic sampling effort. We then built virus subtype sample-based accumulation curves to better estimate sample size targets that capture a specific percentage of virus subtype richness at seven sampling locations. Our study identifies a sampling methodology that will detect an estimated 75% of circulating virus subtypes from a targeted bird population and outlines future surveillance and research priorities that are needed to explore the influence of host and virus biodiversity on emergence and transmission. [ABSTRACT FROM AUTHOR]

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) had caused catastrophic losses in swine industry in China. The current inactivated vaccine provided only limited protection, and the attenuated live vaccine could protect piglets against the HP-PRRSV but there was a possibility that the attenuated virus returned to high virulence. In this study, the eukaryotic expression vector pVAX1© was modified under the control of rabbit β-globin intron II gene and the modified vector pMVAX1© was constructed. Porcine interleukin-2 (IL-2) and GP3-GP5 fusion protein of HP-PRRSV strain SD-JN were highly expressed by pMVAX1©. Mice inoculated with pMVAX1©-GP35 developed significantly higher PRRSV-specific antibody responses and T cell proliferation than those vaccinated with pVAX1©-GP35. pMVAX1©-GP35 was selected as PRRS DNA vaccine candidate and co-administrated with pVAX1©-IL-2 or pMVAX1©-IL-2 in pigs. pMVAX1©-IL-2+pMVAX1©-GP35 could provide enhanced PRRSV-specific antibody responses, T cell proliferation, Th1-type and Th2-type cytokine responses and CTL responses than pMVAX1©-GP35 and pVAX1©-IL-2+pMVAX1©-GP35. Following homologous challenge with HP-PRRSV strain SD-JN, similar with attenuated PRRS vaccine group, pigs inoculated with pMVAX1©-IL-2+pMVAX1©-GP35 showed no clinical signs, almost no lung lesions and no viremia, as compared to those in pMVAX1©-GP35 and pVAX1©-IL-2+pMVAX1©-GP35 groups. It indicated that pMVAX1©-IL-2 effectively increases humoral and cell mediated immune responses of pMVAX1©-GP35. Co-administration of pMVAX1©-IL-2 and pMVAX1©-GP35 might be attractive candidate vaccines for preventing HP-PRRSV infections. [ABSTRACT FROM AUTHOR]

In recent years, a number of zoonotic flaviviruses have emerged worldwide, and wild birds serve as their major reservoirs. Epidemiological surveys of bird populations at various geographical scales can clarify key aspects of the eco-epidemiology of these viruses. In this study, we aimed at exploring the presence of flaviviruses in the western Mediterranean by sampling breeding populations of the yellow-legged gull (Larus michahellis), a widely distributed, anthropophilic, and abundant seabird species. For 3 years, we sampled eggs from 19 breeding colonies in Spain, France, Algeria, and Tunisia. First, ELISAs were used to determine if the eggs contained antibodies against flaviviruses. Second, neutralization assays were used to identify the specific flaviviruses present. Finally, for colonies in which ELISA-positive eggs had been found, chick serum samples and potential vectors, culicid mosquitoes and soft ticks (Ornithodoros maritimus), were collected and analyzed using serology and PCR, respectively. The prevalence of flavivirus-specific antibodies in eggs was highly spatially heterogeneous. In northeastern Spain, on the Medes Islands and in the nearby village of L'Escala, 56% of eggs had antibodies against the flavivirus envelope protein, but were negative for neutralizing antibodies against three common flaviviruses: West Nile, Usutu, and tick-borne encephalitis viruses. Furthermore, little evidence of past flavivirus exposure was obtained for the other colonies. A subset of the Ornithodoros ticks from Medes screened for flaviviral RNA tested positive for a virus whose NS5 gene was 95% similar to that of Meaban virus, a flavivirus previously isolated from ticks of Larus argentatus in western France. All ELISA-positive samples subsequently tested positive for Meaban virus neutralizing antibodies. This study shows that gulls in the western Mediterranean Basin are exposed to a tick-borne Meaban-like virus, which underscores the need of exploring the spatial and temporal distribution of this flavivirus as well as its potential pathogenicity for animals and humans. [ABSTRACT FROM AUTHOR]

Rabbit hepatitis E virus (HEV) is a novel genotype of HEV, and is considered to pose a risk of zoonotic transmission. Research into the systemic distribution of rabbit HEV in rabbits during different periods of infection has rarely been reported. To better understand this virus, we infected rabbits with second-passage rabbit HEV via an intraperitoneal route. After inoculation, the infection showed two types, temporary and constant infection. The detection of HEV RNA in the feces varied with time, and serum antigen correlated with fecal HEV RNA. Viremia only appeared 72 days after inoculation. The rabbits remained antibody negative throughout the experimental period. When HEV was localized, several organs besides the liver were HEV RNA positive. Tissue antigen was observed immunohistochemically in the different cells of various organs, especially in parts of the small intestine and the characteristic rabbit gut-associated lymphoid tissue. These data provide valuable information for future research into the pathogenesis of HEV. [ABSTRACT FROM AUTHOR]

Rift Valley fever virus (RVFV, family Bunyaviridae) is a mosquito-borne pathogen of both livestock and humans, found primarily in Sub-Saharan Africa and the Arabian Peninsula. The viral genome comprises two negative-sense (L and M segments) and one ambisense (S segment) RNAs that encode seven proteins. The S segment encodes the nucleocapsid (N) protein in the negative-sense and a nonstructural (NSs) protein in the positive-sense, though NSs cannot be translated directly from the S segment but rather from a specific subgenomic mRNA. Using reverse genetics we generated a virus, designated rMP12:S-Swap, in which the N protein is expressed from the NSs locus and NSs from the N locus within the genomic S RNA. In cells infected with rMP12:S-Swap NSs is expressed at higher levels with respect to N than in cells infected with the parental rMP12 virus. Despite NSs being the main interferon antagonist and determinant of virulence, growth of rMP12:S-Swap was attenuated in mammalian cells and gave a small plaque phenotype. The increased abundance of the NSs protein did not lead to faster inhibition of host cell protein synthesis or host cell transcription in infected mammalian cells. In cultured mosquito cells, however, infection with rMP12:S-Swap resulted in cell death rather than establishment of persistence as seen with rMP12. Finally, altering the composition of the S segment led to a differential packaging ratio of genomic to antigenomic RNA into rMP12:S-Swap virions. Our results highlight the plasticity of the RVFV genome and provide a useful experimental tool to investigate further the packaging mechanism of the segmented genome. [ABSTRACT FROM AUTHOR]

Binding of influenza viruses to target cells is mediated by the viral surface protein hemagglutinin. To determine the presence of binding sites for influenza A viruses on cells and tissues, soluble hemagglutinins of the H7 and H9 subtype were generated by connecting the hemagglutinin ectodomain to the Fc portion of human immunoglobulin G (H7Fc and H9Fc). Both chimeric proteins bound to different cells and tissues in a sialic acid-dependent manner. Pronounced differences were observed between H7Fc and H9Fc, in the binding both to different mammalian and avian cultured cells and to cryosections of the respiratory epithelium of different virus host species (turkey, chicken and pig). Binding of the soluble hemagglutinins was similar to the binding of virus particles, but showed differences in the binding pattern when compared to two sialic acid-specific plant lectins. These findings were substantiated by a comparative glycan array analysis revealing a very narrow recognition of sialoglycoconjugates by the plant lectins that does not reflect the glycan structures preferentially recognized by H7Fc and H9Fc. Thus, soluble hemagglutinins may serve as sialic acid-specific lectins and are a more reliable indicator of the presence of binding sites for influenza virus HA than the commonly used plant lectins. [ABSTRACT FROM AUTHOR]

Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under “cheating” conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR+ cells do not. [ABSTRACT FROM AUTHOR]

Background: Cluster of differentiation 8 (CD8) is expressed in cytotoxic T cells, where it functions as a co-receptor for the T-cell receptor by binding to major histocompatibility complex class I (MHCI) proteins, which present peptides on the cell surface. CD8A is critical for cell-mediated immune defense and T-cell development. CD8A transcription is controlled by several cis-acting elements and trans-acting elements and is also regulated by DNA methylation. However, the epigenetic regulation of CD8A in the duck and its relationship with virus infection are still unclear. Results: We investigated the epigenetic transcriptional regulatory mechanisms, such as DNA methylation, for the expression of the CD8A and further evaluated the contribution of such epigenetic regulatory mechanisms to DHV-I infection in the duck. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed the highest level of CD8A expression to be in the thymus, followed by the lungs, spleen, and liver, and the levels of CD8A expression were very low in the kidney, cerebrum, cerebellum, and muscle in the duck. RT-qPCR also demonstrated that the CD8A mRNA was down-regulated significantly in morbid ducklings treated with DHV-1 and up-regulated significantly in non-morbid ducklings in all the tissues tested. In addition, hypermethylation of CD8A was detected in the morbid ducklings, whereas relatively low methylation of CD8A was evident in the non-morbid ducklings. The CD8A mRNA level was negatively associated with the CpG methylation level of CD8A and global methylation status. Conclusions: We concluded that the mRNA level of the CD8A was negatively associated with the CpG methylation level of CD8A and global methylation status in the duck, suggesting that the hypermethylation of CD8A may be associated with DHV-1 infection. The first two CpG sites of the CD8A promoter region could be considered as epigenetic biomarkers for resistance breeding against duckling hepatitis disease in the duck. [ABSTRACT FROM AUTHOR]

The rabies virus (RABV) glycoprotein (G) is the principal antigen responsible for the induction of virus neutralizing antibodies (VNA) and is the major modality of protective immunity in animals. A recombinant RABV HEP-Flury strain was generated by reverse genetics to encode two copies of the G-gene (referred to as HEP-dG). The biological properties of HEP-dG were compared to those of the parental virus (HEP-Flury strain). The HEP-dG recombinant virus grew 100 times more efficiently in BHK-21 cell than the parental virus, yet the virulence of the dG recombinant virus in suckling mice was lower than the parental virus. The HEP-dG virus can improve the expression of G-gene mRNA and the G protein and produce more offspring viruses in cells. The amount of G protein revealed a positive relationship with immunogenicity in mice and dogs. The inactivated HEP-dG recombinant virus induced higher levels of VNA and conferred better protection against virulent RABV in mice and dogs than the inactivated parental virus and a commercial vaccine. The protective antibody persisted for at least 12 months. These data demonstrate that the HEP-dG is stable, induces a strong VNA response and confers protective immunity more effectively than the RABV HEP-Flury strain. HEP-dG could be a potential candidate in the development of novel inactivated rabies vaccines [ABSTRACT FROM AUTHOR]

Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under “cheating” conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR+ cells do not. [ABSTRACT FROM AUTHOR]

Herpes B virus (or Herpesvirus simiae or Macacine herpesvirus 1) is endemic in many populations of macaques, both in the wild and in captivity. The virus elicits only mild clinical symptoms (if any) in monkeys, but can be transmitted by various routes, most commonly via bites, to humans where it causes viral encephalitis with a high mortality rate. Hence, herpes B constitutes a considerable occupational hazard for animal caretakers, veterinarians and laboratory personnel. Efforts are therefore being made to reduce the risk of zoonotic infection and to improve prognosis after accidental exposure. Among the measures envisaged are serological surveillance of monkey colonies and specific diagnosis of herpes B zoonosis against a background of antibodies recognizing the closely related human herpes simplex virus (HSV). 422 pentadecapeptides covering, in an overlapping fashion, the entire amino acid sequences of herpes B proteins gB and gD were synthesized and immobilized on glass slides. Antibodies present in monkey sera that bind to subsets of the peptide collection were detected by microserological techniques. With 42 different rhesus macaque sera, 114 individual responses to 18 different antibody target regions (ATRs) were recorded, 17 of which had not been described earlier. This finding may pave the way for a peptide-based, herpes B specific serological diagnostic test. [ABSTRACT FROM AUTHOR]

Epidemiological studies suggest that retroviruses, including human immunodeficiency virus type 1, are associated with cardiomyopathy and myocarditis, but a causal relationship remains to be established. We encountered unusual cardiomyocyte hypertrophy and mitosis in Japanese native fowls infected with subgroup A of the avian leukosis viruses (ALVs-A), which belong to the genus Alpharetrovirus of the family Retroviridae and mainly induce lymphoid neoplasm in chickens. The affected hearts were evaluated by histopathology and immunohistochemistry, viral isolation, viral genome sequencing and experimental infection. There was non-suppurative myocarditis in eighteen fowls and seven of them had abnormal cardiomyocytes, which were distributed predominantly in the left ventricular wall and showed hypertrophic cytoplasm and atypical large nuclei. Nuclear chains and mitosis were frequently noted in these cardiomyocytes and immunohistochemistry for proliferating cell nuclear antigen supported the enhancement of mitotic activity. ALVs were isolated from all affected cases and phylogenic analysis of envSU genes showed that the isolates were mainly classified into two different clusters, suggesting viral genome diversity. In ovo experimental infection with two of the isolates was demonstrated to cause myocarditis and cardiomyocyte hypertrophy similar to those in the naturally occurring lesions and cardiac hamartoma (rhabdomyoma) in a shorter period of time (at 70 days of age) than expected. These results indicate that ALVs cause myocarditis as well as cardiomyocyte abnormality in chickens, implying a pathogenetic mechanism different from insertional mutagenesis and the existence of retrovirus-induced heart disorder. [ABSTRACT FROM AUTHOR]

Comparison of control strategies against animal infectious diseases allows determining optimal strategies according to their epidemiological and/or economic impacts. However, in real life, the choice of a control strategy does not always obey a pure economic or epidemiological rationality. The objective of this study was to analyze the choice of a foot and mouth disease (FMD) control strategy as a decision-making process in which the decision-maker is influenced by several stakeholders (government, agro-food industries, public opinion). For each of these, an indicator of epizootic impact was quantified to compare seven control strategies. We then determined how, in France, the optimal control strategy varied according to the relative weights of stakeholders and to the perception of risk by the decision-maker (risk-neutral/risk-averse). When the scope of decision was national, whatever their perception of risk and the stakeholders' weights, decision-makers chose a strategy based on vaccination. This consensus concealed marked differences between regions, which were connected with the regional breeding characteristics. Vaccination-based strategies were predominant in regions with dense cattle and swine populations, and in regions with a dense population of small ruminants, combined with a medium density of cattle and swine. These differences between regions suggested that control strategies could be usefully adapted to local breeding conditions. We then analyzed the feasibility of adaptive decision-making processes depending on the date and place where the epizootic starts, or on the evolution of the epizootic over time. The initial conditions always explained at least half of the variance of impacts, the remaining variance being attributed to the variability of epizootics evolution. However, the first weeks of this evolution explained a large part of the impacts variability. Although the predictive value of the initial conditions for determining the optimal strategy was weak, adaptive strategies changing dynamically according to the evolution of the epizootic appeared feasible. [ABSTRACT FROM AUTHOR]

In 2001–2005 we sampled permanently marked big brown bats (Eptesicus fuscus) at summer roosts in buildings at Fort Collins, Colorado, for rabies virus neutralizing antibodies (RVNA). Seroprevalence was higher in adult females (17.9%, n = 2,332) than males (9.4%, n = 128; P = 0.007) or volant juveniles (10.2%, n = 738; P<0.0001). Seroprevalence was lowest in a drought year with local insecticide use and highest in the year with normal conditions, suggesting that environmental stress may suppress RVNA production in big brown bats. Seroprevalence also increased with age of bat, and varied from 6.2 to 26.7% among adult females at five roosts sampled each year for five years. Seroprevalence of adult females at 17 other roosts sampled for 1 to 4 years ranged from 0.0 to 47.1%. Using logistic regression, the only ranking model in our candidate set of explanatory variables for serological status at first sampling included year, day of season, and a year by day of season interaction that varied with relative drought conditions. The presence or absence of antibodies in individual bats showed temporal variability. Year alone provided the best model to explain the likelihood of adult female bats showing a transition to seronegative from a previously seropositive state. Day of the season was the only competitive model to explain the likelihood of a transition from seronegative to seropositive, which increased as the season progressed. We found no rabies viral RNA in oropharyngeal secretions of 261 seropositive bats or in organs of 13 euthanized seropositive bats. Survival of seropositive and seronegative bats did not differ. The presence of RVNA in serum of bats should not be interpreted as evidence for ongoing rabies infection. [ABSTRACT FROM AUTHOR]

Vaccination is one of the most efficient ways to control the spread of infectious diseases. Simulations are now widely used to assess how vaccination can limit disease spread as well as mitigate morbidity or mortality in susceptible populations. However, field studies investigating how much vaccines decrease the velocity of epizootic wave-fronts during outbreaks are rare. This study aimed at investigating the effect of vaccination on the propagation of bluetongue, a vector-borne disease of ruminants. We used data from the 2008 bluetongue virus serotype 1 (BTV-1) epizootic of southwest France. As the virus was newly introduced in this area, natural immunity of livestock was absent. This allowed determination of the role of vaccination in changing the velocity of bluetongue spread while accounting for environmental factors that possibly influenced it. The average estimated velocity across the country despite restriction on animal movements was 5.4 km/day, which is very similar to the velocity of spread of the bluetongue virus serotype 8 epizootic in France also estimated in a context of restrictions on animal movements. Vaccination significantly reduced the propagation velocity of BTV-1. In comparison to municipalities with no vaccine coverage, the velocity of BTV-1 spread decreased by 1.7 km/day in municipalities with immunized animals. For the first time, the effect of vaccination has been quantified using data from a real epizootic whilst accounting for environmental factors known to modify the velocity of bluetongue spread. Our findings emphasize the importance of vaccination in limiting disease spread across natural landscape. Finally, environmental factors, specifically those related to vector abundance and activity, were found to be good predictors of the velocity of BTV-1 spread, indicating that these variables need to be adequately accounted for when evaluating the role of vaccination on bluetongue spread. [ABSTRACT FROM AUTHOR]

Accurate and rapid characterization of influenza A virus (IAV) hemagglutinin (HA) and neuraminidase (NA) sequences with respect to subtype and clade is at the basis of extended diagnostic services and implicit to molecular epidemiologic studies. ClassyFlu is a new tool and web service for the classification of IAV sequences of the HA and NA gene into subtypes and phylogenetic clades using discriminatively trained profile hidden Markov models (HMMs), one for each subtype or clade. ClassyFlu merely requires as input unaligned, full-length or partial HA or NA DNA sequences. It enables rapid and highly accurate assignment of HA sequences to subtypes H1–H17 but particularly focusses on the finer grained assignment of sequences of highly pathogenic avian influenza viruses of subtype H5N1 according to the cladistics proposed by the H5N1 Evolution Working Group. NA sequences are classified into subtypes N1–N10. ClassyFlu was compared to semiautomatic classification approaches using BLAST and phylogenetics and additionally for H5 sequences to the new “Highly Pathogenic H5N1 Clade Classification Tool” (IRD-CT) proposed by the Influenza Research Database. Our results show that both web tools (ClassyFlu and IRD-CT), although based on different methods, are nearly equivalent in performance and both are more accurate and faster than semiautomatic classification. A retraining of ClassyFlu to altered cladistics as well as an extension of ClassyFlu to other IAV genome segments or fragments thereof is undemanding. This is exemplified by unambiguous assignment to a distinct cluster within subtype H7 of sequences of H7N9 viruses which emerged in China early in 2013 and caused more than 130 human infections. http://bioinf.uni-greifswald.de/ClassyFlu is a free web service. For local execution, the ClassyFlu source code in PERL is freely available. [ABSTRACT FROM AUTHOR]

Infectious bursal disease virus (IBDV) infection causes immunodeficiency in chickens. To understand cell-mediated immunity during IBDV infection, this study perform a detailed analysis of chicken γc chain (chCD132) and γc family cytokines, including interleukins 2, 4, 7, 9, and 15. The mouse anti-chCD132 monoclonal antibody (mAb) was first generated by the E.coli-expressed γc protein. Immunofluorescence assay further showed that γc was a protein located with the anti-chCD132 mAb on the surface of chicken's splenic mononuclear cells. Real-time quantitative RT-PCR revealed that the chCD132 mRNA transcript was persistently downregulated in embryo fibroblasts, spleen and thymus of chickens infected with IBDV. Correspondingly during IBDV infection, the transcription of five γc family cytokines was downregulated in the thymus and presented an imbalance in the spleen. Fluorescence-activated cell sorting analyses also indicated that the percentage of CD132+CD8+ T cells linearly decreased in the bursa of IBDV-infected chickens. These results confirmed that IBDV infection disturbed the in vivo balance of CD132 and γc family cytokine expression and that IBDV-induced immunodeficiency involved cellular networks related to the γc family. [ABSTRACT FROM AUTHOR]

Many haematophagous insects produce factors that help their blood meal and coincidentally favor pathogen transmission. However nothing is known about the ability of Culicoides midges to interfere with the infectivity of the viruses they transmit. Among these, Bluetongue Virus (BTV) induces a hemorrhagic fever- type disease and its recent emergence in Europe had a major economical impact. We observed that needle inoculation of BTV8 in the site of uninfected C. nubeculosus feeding reduced viraemia and clinical disease intensity compared to plain needle inoculation. The sheep that developed the highest local inflammatory reaction had the lowest viral load, suggesting that the inflammatory response to midge bites may participate in the individual sensitivity to BTV viraemia development. Conversely compared to needle inoculation, inoculation of BTV8 by infected C. nubeculosus bites promoted viraemia and clinical symptom expression, in association with delayed IFN- induced gene expression and retarded neutralizing antibody responses. The effects of uninfected and infected midge bites on BTV viraemia and on the host response indicate that BTV transmission by infected midges is the most reliable experimental method to study the physio-pathological events relevant to a natural infection and to pertinent vaccine evaluation in the target species. It also leads the way to identify the promoting viral infectivity factors of infected Culicoides in order to possibly develop new control strategies against BTV and other Culicoides transmitted viruses. [ABSTRACT FROM AUTHOR]

Ducks are important maintenance hosts for avian influenza, including H5N1 highly pathogenic avian influenza viruses. A previous study indicated that persistence of H5N1 viruses in ducks after the development of humoral immunity may drive viral evolution following immune selection. As H5N1 HPAI is endemic in Indonesia, this mechanism may be important in understanding H5N1 evolution in that region. To determine the capability of domestic ducks to maintain prolonged shedding of Indonesian clade 2.1 H5N1 virus, two groups of Pekin ducks were inoculated through the eyes, nostrils and oropharynx and viral shedding and transmission investigated. Inoculated ducks (n = 15), which were mostly asymptomatic, shed infectious virus from the oral route from 1 to 8 days post inoculation, and from the cloacal route from 2–8 dpi. Viral ribonucleic acid was detected from 1–15 days post inoculation from the oral route and 1–24 days post inoculation from the cloacal route (cycle threshold <40). Most ducks seroconverted in a range of serological tests by 15 days post inoculation. Virus was efficiently transmitted during acute infection (5 inoculation-infected to all 5 contact ducks). However, no evidence for transmission, as determined by seroconversion and viral shedding, was found between an inoculation-infected group (n = 10) and contact ducks (n = 9) when the two groups only had contact after 10 days post inoculation. Clinical disease was more frequent and more severe in contact-infected (2 of 5) than inoculation-infected ducks (1 of 15). We conclude that Indonesian clade 2.1 H5N1 highly pathogenic avian influenza virus does not persist in individual ducks after acute infection. [ABSTRACT FROM AUTHOR]

Background: Striped skunks (Mephitis mephitis) are susceptible to infection with some influenza A viruses. However, the viral shedding capability of this peri-domestic mammal and its potential role in influenza A virus ecology are largely undetermined. Methodology/Principal Findings: Striped skunks were experimentally infected with a low pathogenic (LP) H4N6 avian influenza virus (AIV) and monitored for 20 days post infection (DPI). All of the skunks exposed to H4N6 AIV shed large quantities of viral RNA, as detected by real-time RT-PCR and confirmed for live virus with virus isolation, from nasal washes and oral swabs (maximum ≤106.02 PCR EID50 equivalent/mL and ≤105.19 PCR EID50 equivalent/mL, respectively). Some evidence of potential fecal shedding was also noted. Following necropsy on 20 DPI, viral RNA was detected in the nasal turbinates of one individual. All treatment animals yielded evidence of a serological response by 20 DPI. Conclusions/Significance: These results indicate that striped skunks have the potential to shed large quantities of viral RNA through the oral and nasal routes following exposure to a LP AIV. Considering the peri-domestic nature of these animals, along with the duration of shedding observed in this species, their presence on poultry and waterfowl operations could influence influenza A virus epidemiology. For example, this species could introduce a virus to a naive poultry flock or act as a trafficking mechanism of AIV to and from an infected poultry flock to naive flocks or wild bird populations. [ABSTRACT FROM AUTHOR]

In 2001–2005 we sampled permanently marked big brown bats (Eptesicus fuscus) at summer roosts in buildings at Fort Collins, Colorado, for rabies virus neutralizing antibodies (RVNA). Seroprevalence was higher in adult females (17.9%, n = 2,332) than males (9.4%, n = 128; P = 0.007) or volant juveniles (10.2%, n = 738; P<0.0001). Seroprevalence was lowest in a drought year with local insecticide use and highest in the year with normal conditions, suggesting that environmental stress may suppress RVNA production in big brown bats. Seroprevalence also increased with age of bat, and varied from 6.2 to 26.7% among adult females at five roosts sampled each year for five years. Seroprevalence of adult females at 17 other roosts sampled for 1 to 4 years ranged from 0.0 to 47.1%. Using logistic regression, the only ranking model in our candidate set of explanatory variables for serological status at first sampling included year, day of season, and a year by day of season interaction that varied with relative drought conditions. The presence or absence of antibodies in individual bats showed temporal variability. Year alone provided the best model to explain the likelihood of adult female bats showing a transition to seronegative from a previously seropositive state. Day of the season was the only competitive model to explain the likelihood of a transition from seronegative to seropositive, which increased as the season progressed. We found no rabies viral RNA in oropharyngeal secretions of 261 seropositive bats or in organs of 13 euthanized seropositive bats. Survival of seropositive and seronegative bats did not differ. The presence of RVNA in serum of bats should not be interpreted as evidence for ongoing rabies infection. [ABSTRACT FROM AUTHOR]

Background: Striped skunks (Mephitis mephitis) are susceptible to infection with some influenza A viruses. However, the viral shedding capability of this peri-domestic mammal and its potential role in influenza A virus ecology are largely undetermined. Methodology/Principal Findings: Striped skunks were experimentally infected with a low pathogenic (LP) H4N6 avian influenza virus (AIV) and monitored for 20 days post infection (DPI). All of the skunks exposed to H4N6 AIV shed large quantities of viral RNA, as detected by real-time RT-PCR and confirmed for live virus with virus isolation, from nasal washes and oral swabs (maximum ≤106.02 PCR EID50 equivalent/mL and ≤105.19 PCR EID50 equivalent/mL, respectively). Some evidence of potential fecal shedding was also noted. Following necropsy on 20 DPI, viral RNA was detected in the nasal turbinates of one individual. All treatment animals yielded evidence of a serological response by 20 DPI. Conclusions/Significance: These results indicate that striped skunks have the potential to shed large quantities of viral RNA through the oral and nasal routes following exposure to a LP AIV. Considering the peri-domestic nature of these animals, along with the duration of shedding observed in this species, their presence on poultry and waterfowl operations could influence influenza A virus epidemiology. For example, this species could introduce a virus to a naive poultry flock or act as a trafficking mechanism of AIV to and from an infected poultry flock to naive flocks or wild bird populations. [ABSTRACT FROM AUTHOR]

The ongoing global spread of “exotic” farm animals, such as water buffaloes, which carry their native sets of viruses, may bear unknown risks for the animals, into whose ecological niches the former are introduced and vice versa. Here, we report on the occurrence of malignant catarrhal fever (MCF) on Swiss farms, where “exotic” water buffaloes were kept together with “native” animals, i.e. cattle, sheep, and goats. In the first farm with 56 water buffaloes, eight cases of MCF due to ovine herpesvirus-2 (OvHV-2) were noted, whereas additional ten water buffaloes were subclinically infected with either OvHV-2 or caprine herpesvirus-2 (CpHV-2). On the second farm, 13 water buffaloes were infected with CpHV-2 and two of those succumbed to MCF. In neither farm, any of the two viruses were detected in cattle, but the Macaviruses were present at high prevalence among their original host species, sheep and goats, respectively. On the third farm, sheep were kept well separated from water buffaloes and OvHV-2 was not transmitted to the buffaloes, despite of high prevalence of the virus among the sheep. Macavirus DNA was frequently detected in the nasal secretions of virus-positive animals and in one instance OvHV-2 was transmitted vertically to an unborn water buffalo calf. Thus, water buffaloes seem to be more susceptible than cattle to infection with either Macavirus; however, MCF did not develop as frequently. Therefore, water buffaloes seem to represent an interesting intermediate-type host for Macaviruses. Consequently, water buffaloes in their native, tropic environments may be vulnerable and endangered to viruses that originate from seemingly healthy, imported sheep and goats. [ABSTRACT FROM AUTHOR]

Background: Arthropod-borne viruses are important emerging pathogens world-wide. Viruses transmitted by mosquitoes, such as dengue, yellow fever, and Japanese encephalitis viruses, infect hundreds of millions of people and animals each year. Global surveillance of these viruses in mosquito vectors using molecular based assays is critical for prevention and control of the associated diseases. Here, we report an oligonucleotide DNA microarray design, termed ArboChip5.1, for multi-gene detection and identification of mosquito-borne RNA viruses from the genera Flavivirus (family Flaviviridae), Alphavirus (Togaviridae), Orthobunyavirus (Bunyaviridae), and Phlebovirus (Bunyaviridae). Methodology/Principal Findings: The assay utilizes targeted PCR amplification of three genes from each virus genus for electrochemical detection on a portable, field-tested microarray platform. Fifty-two viruses propagated in cell-culture were used to evaluate the specificity of the PCR primer sets and the ArboChip5.1 microarray capture probes. The microarray detected all of the tested viruses and differentiated between many closely related viruses such as members of the dengue, Japanese encephalitis, and Semliki Forest virus clades. Laboratory infected mosquitoes were used to simulate field samples and to determine the limits of detection. Additionally, we identified dengue virus type 3, Japanese encephalitis virus, Tembusu virus, Culex flavivirus, and a Quang Binh-like virus from mosquitoes collected in Thailand in 2011 and 2012. Conclusions/Significance: We demonstrated that the described assay can be utilized in a comprehensive field surveillance program by the broad-range amplification and specific identification of arboviruses from infected mosquitoes. Furthermore, the microarray platform can be deployed in the field and viral RNA extraction to data analysis can occur in as little as 12 h. The information derived from the ArboChip5.1 microarray can help to establish public health priorities, detect disease outbreaks, and evaluate control programs. [ABSTRACT FROM AUTHOR]

The rapid discovery of novel viruses using next generation sequencing (NGS) technologies including DNA-Seq and RNA-Seq, has greatly expanded our understanding of viral diversity in recent years. The timely identification of novel viruses using NGS technologies is also important for us to control emerging infectious diseases caused by novel viruses. In this study, we identified a novel duck coronavirus (CoV), distinct with chicken infectious bronchitis virus (IBV), using RNA-Seq. The novel duck-specific CoV was a potential novel species within the genus Gammacoronavirus, as indicated by sequences of three regions in the viral 1b gene. We also performed a survey of CoVs in domestic fowls in China using reverse-transcription polymerase chain reaction (RT-PCR), targeting the viral nucleocapsid (N) gene. A total of 102 CoV positives were identified through the survey. Phylogenetic analysis of the viral N sequences suggested that CoVs in domestic fowls have diverged into several region-specific or host-specific clades or subclades in the world, and IBVs can infect ducks, geese and pigeons, although they mainly circulate in chickens. Moreover, this study provided novel data supporting the notion that some host-specific CoVs other than IBVs circulate in ducks, geese and pigeons, and indicated that the novel duck-specific CoV identified through RNA-Seq in this study is genetically closer to some CoVs circulating in wild water fowls. Taken together, this study shed new insight into the diversity, distribution, evolution and control of avian CoVs. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease (FMD) is a trans-boundary viral disease of livestock, which causes huge economic losses and constitutes a serious infectious threat for livestock farming worldwide. Early diagnosis of FMD helps to diminish its impact by adequate outbreak management. In this study, we describe the development of a real-time reverse transcription recombinase polymerase amplification (RT-RPA) assay for the detection of FMD virus (FMDV). The FMDV RT-RPA design targeted the 3D gene of FMDV and a 260 nt molecular RNA standard was used for assay validation. The RT-RPA assay was fast (4–10 minutes) and the analytical sensitivity was determined at 1436 RNA molecules detected by probit regression analysis. The FMDV RT-RPA assay detected RNA prepared from all seven FMDV serotypes but did not detect classical swine fever virus or swine vesicular disease virus. The FMDV RT-RPA assay was used in the field during the recent FMD outbreak in Egypt. In clinical samples, reverse transcription polymerase chain reaction (RT-PCR) and RT-RPA showed a diagnostic sensitivity of 100% and 98%, respectively. In conclusion, FMDV RT-RPA was quicker and much easier to handle in the field than real-time RT-PCR. Thus RT-RPA could be easily implemented to perform diagnostics at quarantine stations or farms for rapid spot-of-infection detection. [ABSTRACT FROM AUTHOR]

Airborne transmission of influenza A virus (IAV) in swine is speculated to be an important route of virus dissemination, but data are scarce. This study attempted to detect and quantify airborne IAV by virus isolation and RRT-PCR in air samples collected under field conditions. This was accomplished by collecting air samples from four acutely infected pig farms and locating air samplers inside the barns, at the external exhaust fans and downwind from the farms at distances up to 2.1 km. IAV was detected in air samples collected in 3 out of 4 farms included in the study. Isolation of IAV was possible from air samples collected inside the barn at two of the farms and in one farm from the exhausted air. Between 13% and 100% of samples collected inside the barns tested RRT-PCR positive with an average viral load of 3.20E+05 IAV RNA copies/m3 of air. Percentage of exhaust positive air samples also ranged between 13% and 100% with an average viral load of 1.79E+04 RNA copies/m3 of air. Influenza virus RNA was detected in air samples collected between 1.5 and 2.1 Km away from the farms with viral levels significantly lower at 4.65E+03 RNA copies/m3. H1N1, H1N2 and H3N2 subtypes were detected in the air samples and the hemagglutinin gene sequences identified in the swine samples matched those in aerosols providing evidence that the viruses detected in the aerosols originated from the pigs in the farms under study. Overall our results indicate that pigs can be a source of IAV infectious aerosols and that these aerosols can be exhausted from pig barns and be transported downwind. The results from this study provide evidence of the risk of aerosol transmission in pigs under field conditions. [ABSTRACT FROM AUTHOR]

Background: Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006–2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture. Methodology/Principal Findings: A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination. Conclusions/Significance: Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed. [ABSTRACT FROM AUTHOR]

A cytopathic virus was isolated using Madin-Darby bovine kidney (MDBK) cells from lung tissue of alpaca that died of a severe respiratory infection. To identify the virus, the infected cell culture supernatant was enriched for virus particles and a generic, PCR-based method was used to amplify potential viral sequences. Genomic sequence data of the alpaca isolate was obtained and compared with sequences of known viruses. The new alpaca virus sequence was most similar to recently designated Enterovirus species F, previously bovine enterovirus (BEVs), viruses that are globally prevalent in cattle, although they appear not to cause significant disease. Because bovine enteroviruses have not been previously reported in U.S. alpaca, we suspect that this type of infection is fairly rare, and in this case appeared not to spread beyond the original outbreak. The capsid sequence of the detected virus had greatest homology to Enterovirus F type 1 (indicating that the virus should be considered a member of serotype 1), but the virus had greater homology in 2A protease sequence to type 3, suggesting that it may have been a recombinant. Identifying pathogens that infect a new host species for the first time can be challenging. As the disease in a new host species may be quite different from that in the original or natural host, the pathogen may not be suspected based on the clinical presentation, delaying diagnosis. Although this virus replicated in MDBK cells, existing standard culture and molecular methods could not identify it. In this case, a highly sensitive generic PCR-based pathogen-detection method was used to identify this pathogen. [ABSTRACT FROM AUTHOR]

The wetlands of the Brazilian Pantanal host large concentrations of diverse wildlife species and hematophagous arthropods, conditions that favor the circulation of zoonotic arboviruses. A recent study from the Nhecolândia sub-region of Pantanal reported serological evidence of various flaviviruses, including West Nile virus and Ilheus virus (ILHV). According to the age of seropositive horses, at least three flaviviruses, including ILHV, circulated in the Brazilian Pantanal between 2005 and 2009. To extend this study, we collected 3,234 adult mosquitoes of 16 species during 2009 and 2010 in the same sub-region. Mosquito pool homogenates were assayed for infectious virus on C6/36 and Vero cell monolayers and also tested for flaviviral RNA by a group-specific real-time RT-PCR. One pool containing 50 non-engorged female specimens of Aedes scapularis tested positive for ILHV by culture and for ILHV RNA by real-time RT-PCR, indicating a minimum infection rate of 2.5 per 1000. Full-length genomic sequence exhibited 95% identity to the only full genome sequence available for ILHV. The present data confirm the circulation of ILHV in the Brazilian Pantanal. [ABSTRACT FROM AUTHOR]

Background: Rift Valley fever virus (RVFV) is a mosquito-borne pathogen causing an important disease in ruminants often transmitted to humans after epizootic outbreaks in African and Arabian countries. To help combat the spread of the disease, prophylactic measures need to be developed and/or improved. Methodology/Principal Findings: In this work, we evaluated the immunogenicity and protective efficacy of recombinant plasmid DNA and modified vaccinia virus Ankara (rMVA) vectored vaccines against Rift Valley fever in mice. These recombinant vaccines encoded either of two components of the Rift Valley fever virus: the viral glycoproteins (Gn/Gc) or the nucleoprotein (N). Following lethal challenge with live RVFV, mice immunized with a single dose of the rMVA-Gn/Gc vaccine showed no viraemia or clinical manifestation of disease, but mounted RVFV neutralizing antibodies and glycoprotein specific CD8+ T-cell responses. Neither DNA-Gn/Gc alone nor a heterologous prime-boost immunization schedule (DNA-Gn/Gc followed by rMVAGn/Gc) was better than the single rMVA-Gn/Gc immunization schedule with regards to protective efficacy. However, the rMVA-Gn/Gc vaccine failed to protect IFNAR−/− mice upon lethal RVFV challenge suggesting a role for innate responses in protection against RVFV. Despite induction of high titer antibodies against the RVFV nucleoprotein, the rMVA-N vaccine, whether in homologous or heterologous prime-boost schedules with the corresponding recombinant DNA vaccine, only conferred partial protection to RVFV challenge. Conclusions/Significance: Given the excellent safety profile of rMVA based vaccines in humans and animals, our data supports further development of rMVA-Gn/Gc as a vaccine strategy that can be used for the prevention of Rift Valley fever in both humans and livestock. [ABSTRACT FROM AUTHOR]

Myxoma virus (MYXV)-encoded protein M029 is a member of the poxvirus E3 family of dsRNA-binding proteins that antagonize the cellular interferon signaling pathways. In order to investigate additional functions of M029, we have constructed a series of targeted M029-minus (vMyx-M029KO and vMyx-M029ID) and V5-tagged M029 MYXV. We found that M029 plays a pivotal role in determining the cellular tropism of MYXV in all mammalian cells tested. The M029-minus viruses were able to replicate only in engineered cell lines that stably express a complementing protein, such as vaccinia E3, but underwent abortive or abated infection in all other tested mammalian cell lines. The M029-minus viruses were dramatically attenuated in susceptible host European rabbits and caused no observable signs of myxomatosis. Using V5-tagged M029 virus, we observed that M029 expressed as an early viral protein is localized in both the nuclear and cytosolic compartments in virus-infected cells, and is also incorporated into virions. Using proteomic approaches, we have identified Protein Kinase R (PKR) and RNA helicase A (RHA)/DHX9 as two cellular binding partners of M029 protein. In virus-infected cells, M029 interacts with PKR in a dsRNA-dependent manner, while binding with DHX9 was not dependent on dsRNA. Significantly, PKR knockdown in human cells rescued the replication defect of the M029-knockout viruses. Unexpectedly, this rescue of M029-minus virus replication by PKR depletion could then be reversed by RHA/DHX9 knockdown in human monocytic THP1 cells. This indicates that M029 not only inhibits generic PKR anti-viral pathways, but also binds and conscripts RHA/DHX9 as a pro-viral effector to promote virus replication in THP1 cells. Thus, M029 is a critical host range and virulence factor for MYXV that is required for replication in all mammalian cells by antagonizing PKR-mediated anti-viral functions, and also conscripts pro-viral RHA/DHX9 to promote viral replication specifically in myeloid cells. [ABSTRACT FROM AUTHOR]

Background: Duck is an economically important poultry and animal model for human viral hepatitis B. However, the molecular mechanisms underlying host–virus interaction remain unclear because of limited information on the duck genome. This study aims to characterize the duck normal liver transcriptome and to identify the differentially expressed transcripts at 24 h after duck hepatitis A virus genotype C (DHAV-C) infection using Illumina–Solexa sequencing. Results: After removal of low-quality sequences and assembly, a total of 52,757 unigenes was obtained from the normal liver group. Further blast analysis showed that 18,918 unigenes successfully matched the known genes in the database. GO analysis revealed that 25,116 unigenes took part in 61 categories of biological processes, cellular components, and molecular functions. Among the 25 clusters of orthologous group categories (COG), the cluster for “General function prediction only” represented the largest group, followed by “Transcription” and “Replication, recombination, and repair.” KEGG analysis showed that 17,628 unigenes were involved in 301 pathways. Through comparison of normal and infected transcriptome data, we identified 20 significantly differentially expressed unigenes, which were further confirmed by real-time polymerase chain reaction. Of the 20 unigenes, nine matched the known genes in the database, including three up-regulated genes (virus replicase polyprotein, LRRC3B, and PCK1) and six down-regulated genes (CRP, AICL-like 2, L1CAM, CYB26A1, CHAC1, and ADAM32). The remaining 11 novel unigenes that did not match any known genes in the database may provide a basis for the discovery of new transcripts associated with infection. Conclusion: This study provided a gene expression pattern for normal duck liver and for the previously unrecognized changes in gene transcription that are altered during DHAV-C infection. Our data revealed useful information for future studies on the duck genome and provided new insights into the molecular mechanism of host–DHAV-C interaction. [ABSTRACT FROM AUTHOR]

African horse sickness virus (AHSV) belongs to the genus Orbivirus. We have now engineered naked DNAs and recombinant modified vaccinia virus Ankara (rMVA) expressing VP2 and NS1 proteins from AHSV-4. IFNAR(−/−) mice inoculated with DNA/rMVA-VP2,-NS1 from AHSV-4 in an heterologous prime-boost vaccination strategy generated significant levels of neutralizing antibodies specific of AHSV-4. In addition, vaccination stimulated specific T cell responses against the virus. The vaccine elicited partial protection against an homologous AHSV-4 infection and induced cross-protection against the heterologous AHSV-9. Similarly, IFNAR(−/−) mice vaccinated with an homologous prime-boost strategy with rMVA-VP2-NS1 from AHSV-4 developed neutralizing antibodies and protective immunity against AHSV-4. Furthermore, the levels of immunity were very high since none of vaccinated animals presented viraemia when they were challenged against the homologous AHSV-4 and very low levels when they were challenged against the heterologous virus AHSV-9. These data suggest that the immunization with rMVA/rMVA was more efficient in protection against a virulent challenge with AHSV-4 and both strategies, DNA/rMVA and rMVA/rMVA, protected against the infection with AHSV-9. The inclusion of the protein NS1 in the vaccine formulations targeting AHSV generates promising multiserotype vaccines. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) is a worldwide distributed mosquito-borne flavivirus that naturally cycles between birds and mosquitoes, although it can infect multiple vertebrate hosts including horses and humans. This virus is responsible for recurrent epidemics of febrile illness and encephalitis, and has recently become a global concern. WNV requires to transit through intracellular acidic compartments at two different steps to complete its infectious cycle. These include fusion between the viral envelope and the membrane of endosomes during viral entry, and virus maturation in the trans-Golgi network. In this study, we followed a genetic approach to study the connections between viral components and acidic pH. A WNV mutant with increased resistance to the acidotropic compound NH4Cl, which blocks organelle acidification and inhibits WNV infection, was selected. Nucleotide sequencing revealed that this mutant displayed a single amino acid substitution (Lys 3 to Glu) on the highly basic internal capsid or core (C) protein. The functional role of this replacement was confirmed by its introduction into a WNV infectious clone. This single amino acid substitution also increased resistance to other acidification inhibitor (concanamycin A) and induced a reduction of the neurovirulence in mice. Interestingly, a naturally occurring accompanying mutation found on prM protein abolished the resistant phenotype, supporting the idea of a genetic crosstalk between the internal C protein and the external glycoproteins of the virion. The findings here reported unveil a non-previously assessed connection between the C viral protein and the acidic pH necessary for entry and proper exit of flaviviruses. [ABSTRACT FROM AUTHOR]

Adenoviruses are DNA viruses that infect a number of vertebrate hosts and are associated with both sporadic and epidemic disease in humans. We previously identified a novel adenovirus, titi monkey adenovirus (TMAdV), as the cause of a fulminant pneumonia outbreak in a colony of titi monkeys (Callicebus cupreus) at a national primate center in 2009. Serological evidence of infection by TMAdV was also found in a human researcher at the facility and household family member, raising concerns for potential cross-species transmission of the virus. Here we present experimental evidence of cross-species TMAdV infection in common marmosets (Callithrix jacchus). Nasal inoculation of a cell cultured-adapted TMAdV strain into three marmosets produced an acute, mild respiratory illness characterized by low-grade fever, reduced activity, anorexia, and sneezing. An increase in virus-specific neutralization antibody titers accompanied the development of clinical signs. Although serially collected nasal swabs were positive for TMAdV for at least 8 days, all 3 infected marmosets spontaneously recovered by day 12 post-inoculation, and persistence of the virus in tissues could not be established. Thus, the pathogenesis of experimental inoculation of TMAdV in common marmosets resembled the mild, self-limiting respiratory infection typically seen in immunocompetent human hosts rather than the rapidly progressive, fatal pneumonia observed in 19 of 23 titi monkeys during the prior 2009 outbreak. These findings further establish the potential for adenovirus cross-species transmission and provide the basis for development of a monkey model useful for assessing the zoonotic potential of adenoviruses. [ABSTRACT FROM AUTHOR]