Modeling the 2014-2015 Vesicular Stomatitis Outbreak in the United States Using an SEIR-SEI Approach.

Vesicular stomatitis (VS) is a vector-borne livestock disease caused by the vesicular stomatitis New Jersey virus (VSNJV). This study presents the first application of an SEIR-SEI compartmental model to analyze VSNJV transmission dynamics. Focusing on the 2014-2015 outbreak in the United States, the model integrates vertebrate hosts and insect vector demographics while accounting for heterogeneous competency within the populations and observation bias in documented disease cases. Key epidemiological parameters were estimated using Bayesian inference and Markov chain Monte Carlo (MCMC) methods, including the force of infection, effective reproduction number (Rt), and incubation periods. The model revealed significant underreporting, with only 10-24% of infections documented, 23% of which presented with clinical symptoms. These findings underscore the importance of including competence and imperfect detection in disease models to depict outbreak dynamics and inform effective control strategies accurately. As a baseline model, this SEIR-SEI implementation is intended to serve as a foundation for future refinements and expansions to improve our understanding of VS dynamics. Enhanced surveillance and targeted interventions are recommended to manage future VS outbreaks.

Interrogating Genomes and Geography to Unravel Multiyear Vesicular Stomatitis Epizootics.

We conducted an integrative analysis to elucidate the spatial epidemiological patterns of the Vesicular Stomatitis New Jersey virus (VSNJV) during the 2014-15 epizootic cycle in the United States (US). Using georeferenced VSNJV genomics data, confirmed vesicular stomatitis (VS) disease cases from surveillance, and a suite of environmental factors, our study assessed environmental and phylogenetic similarity to compare VS cases reported in 2014 and 2015. Despite uncertainties from incomplete virus sampling and cross-scale spatial processes, patterns suggested multiple independent re-invasion events concurrent with potential viral overwintering between sequential seasons. Our findings pointed to a geographically defined southern virus pool at the US-Mexico interface as the source of VSNJV invasions and overwintering sites. Phylodynamic analysis demonstrated an increase in virus diversity before a rise in case numbers and a pronounced reduction in virus diversity during the winter season, indicative of a genetic bottleneck and a significant narrowing of virus variation between the summer outbreak seasons. Environment-vector interactions underscored the central role of meta-population dynamics in driving disease spread. These insights emphasize the necessity for location- and time-specific management practices, including rapid response, movement restrictions, vector control, and other targeted interventions.

Vesicular stomatitis virus in two species of rhinoceros at a California zoological park.

OBJECTIVE: To describe an outbreak of vesicular stomatitis virus (VSV) in southern white rhinoceros (SWR; Ceratotherium simum simum) and greater one-horned rhinoceros (GOHR; Rhinoceros unicornis) at a safari park in San Diego, CA, from May to September 2023. ANIMALS: 21 SWR and 5 GOHR in professionally managed care. METHODS: Rhinoceros of both species presented with a range of clinical signs and severities. Lesion locations were categorized as cutaneous (coronary bands, heels and soles, limbs, ventrum, neck folds, and ears) and mucocutaneous (lips, nostrils, mucous membranes of the oral cavity, and vulva). Clinical signs included lethargy, lameness, difficulty with prehension, hyporexia to anorexia, and hypersalivation. Severely affected rhinoceros had clinical pathology findings consistent with systemic inflammation. RESULTS: Vesicular stomatitis New Jersey virus was confirmed via PCR from swabs of lesions in 10/26 (38%) rhinoceros. Of these 10 confirmed cases, 9 (90%) were SWR and 1 (10%) was a GOHR. A further 6/26 (24%) were considered probable cases, and 10/26 (38%) were considered suspect cases based on clinical signs, but the inability to appropriately sample due to the housing environment precluded confirmation. Histopathology samples from 3 rhinoceros were consistent with VSV, and viral RNA was localized in histologic lesions via RNA in situ hybridization for 1 case. All rhinoceros survived infection despite severe systemic illness in 2 animals. CLINICAL RELEVANCE: This case series describes the clinical appearance and progression of VSV in 2 rhinoceros species. To the authors' knowledge, this is the first report of VSV in a rhinoceros.

Validation of a site-specific recombination cloning technique for the rapid development of a full-length cDNA clone of a virulent field strain of vesicular stomatitis New Jersey virus.

This study reports the use of a site-specific recombination cloning technique for rapid development of a full-length cDNA clone that can produce infectious vesicular stomatitis New Jersey virus (VSNJV). The full-length genome of the epidemic VSNJV NJ0612NME6 strain was amplified in four overlapping cDNA fragments which were linked together and cloned into a vector plasmid by site-specific recombination. Furthermore, to derive infectious virus, three supporting plasmid vectors containing either the nucleoprotein (N), phosphoprotein (P) or polymerase (L) genes were constructed using the same cloning methodology. Recovery of recombinant VSNJV was achieved after transfecting all four vectors on into BSR-T7/5 cells, a BHK-derived cell line stably expressing T7 RNA polymerase (PMID: 9847328). In vitro characterization of recombinant and parental viruses revealed similar growth kinetics and plaque morphologies. Furthermore, experimental infection of pigs with the recombinant virus resulted in severe vesicular stomatitis with clinical signs similar to those previously reported for the parental field strain. These results validate the use of site-directed specific recombination cloning as a useful alternative method for rapid construction of stable full-length cDNA clones from vesicular stomatitis field strains. The approach reported herein contributes to the improvement of previously published methodologies for the development of full-length cDNA clones of this relevant virus.

Oncolytic Recombinant Vesicular Stomatitis Virus (VSV) Is Nonpathogenic and Nontransmissible in Pigs, a Natural Host of VSV.

Vesicular stomatitis virus (VSV) is a negative-stranded RNA virus that naturally causes disease in livestock including horses, cattle and pigs. The two main identified VSV serotypes are New Jersey (VSNJV) and Indiana (VSIV). VSV is a rapidly replicating, potently immunogenic virus that has been engineered to develop novel oncolytic therapies for cancer treatment. Swine are a natural host for VSV and provide a relevant and well-established model, amenable to biological sampling to monitor virus shedding and neutralizing antibodies. Previous reports have documented the pathogenicity and transmissibility of wild-type isolates and recombinant strains of VSIV and VSNJV using the swine model. Oncolytic VSV engineered to express interferon-beta (IFNß) and the sodium iodide symporter (NIS), VSV-IFNß-NIS, has been shown to be a potent new therapeutic agent inducing rapid and durable tumor remission following systemic therapy in preclinical mouse models. VSV-IFNß-NIS is currently undergoing clinical evaluation for the treatment of advanced cancer in human and canine patients. To support clinical studies and comprehensively assess the risk of transmission to susceptible species, we tested the pathogenicity and transmissibility of oncolytic VSV-IFNß-NIS using the swine model. Following previously established protocols to evaluate VSV pathogenicity, intradermal inoculation with 107 TCID50 VSV-IFNß-NIS caused no observable symptoms in pigs. There was no detectable shedding of infectious virus in VSV-IFNß-NIS in biological excreta of inoculated pigs or exposed naive pigs kept in direct contact throughout the experiment. VSV-IFNß-NIS inoculated pigs became seropositive for VSV antibodies, while contact pigs displayed no symptoms of VSV infection, and importantly did not seroconvert. These data indicate that oncolytic VSV is both nonpathogenic and not transmissible in pigs, a natural host. These findings support further clinical development of oncolytic VSV-IFNß-NIS as a safe therapeutic for human and canine cancer.

Development of a reverse transcription loop-mediated isothermal amplification assay for the detection of vesicular stomatitis New Jersey virus: Use of rapid molecular assays to differentiate between vesicular disease viruses.

Vesicular stomatitis (VS) is endemic in Central America and northern regions of South America, where sporadic outbreaks in cattle and pigs can cause clinical signs that are similar to foot-and-mouth disease (FMD). There is therefore a pressing need for rapid, sensitive and specific differential diagnostic assays that are suitable for decision making in the field. RT-LAMP assays have been developed for vesicular diseases such as FMD and swine vesicular disease (SVD) but there is currently no RT-LAMP assay that can detect VS virus (VSV), nor are there any multiplex RT-LAMP assays which permit rapid discrimination between these 'look-a-like' diseases in situ. This study describes the development of a novel RT-LAMP assay for the detection of VSV focusing on the New Jersey (VSNJ) serotype, which has caused most of the recent VS cases in the Americas. This RT-LAMP assay was combined in a multiplex format combining molecular lateral-flow devices for the discrimination between FMD and VS. This assay was able to detect representative VSNJV's and the limit of detection of the singleplex and multiplex VSNJV RT-LAMP assays were equivalent to laboratory based real-time RT-PCR assays. A similar multiplex RT-LAMP assay was developed to discriminate between FMDV and SVDV, showing that FMDV, SVDV and VSNJV could be reliably detected within epithelial suspensions without the need for prior RNA extraction, providing an approach that could be used as the basis for a rapid and low cost assay for differentiation of FMD from other vesicular diseases in the field.

Phylogeographic characteristics of vesicular stomatitis New Jersey viruses circulating in Mexico from 2005 to 2011 and their relationship to epidemics in the United States.

We analyzed the phylogenetic and time-space relationships (phylodynamics) of 181 isolates of vesicular stomatitis New Jersey virus (VSNJV) causing disease in Mexico and the United States (US) from 2005 through 2012. We detail the emergence of a genetic lineage in southern Mexico causing outbreaks in central Mexico spreading into northern Mexico and eventually into the US. That emerging lineage showed higher nucleotide sequence identity (99.5%) than that observed for multiple lineages circulating concurrently in southern Mexico (96.8%). Additionally, we identified 58 isolates from Mexico that, unlike previous isolates from Mexico, grouped with northern Central America clade II viruses. This study provides the first direct evidence for the emergence and northward migration of a specific VSNJV genetic lineage from endemic areas in Mexico causing VS outbreaks in the US. In addition we document the emergence of a Central American VSNJV genetic lineage moving northward and causing outbreaks in central Mexico.

Vesicular stomatitis outbreak in the southwestern United States, 2012.

Vesicular stomatitis is a viral disease primarily affecting horses and cattle when it occurs in the United States. Outbreaks in the southwestern United States occur sporadically, with initial cases typically occurring in Texas, New Mexico, or Arizona and subsequent cases occurring in a northward progression. The viruses causing vesicular stomatitis can be transmitted by direct contact of lesioned animals with other susceptible animals, but transmission is primarily through arthropod vectors. In 2012, an outbreak of vesicular stomatitis in the United States occurred that was caused by Vesicular stomatitis New Jersey virus serotype. Overall, 51 horses on 36 premises in 2 states were confirmed positive. Phylogenetic analysis of the virus indicated that it was most closely related to viruses detected in the state of Veracruz, Mexico, in 2000.

Genetically modified VSV(NJ) vector is capable of accommodating a large foreign gene insert and allows high level gene expression.

It is desirable to develop a RNA virus vector capable of accommodating large foreign genes for high level gene expression. Vesicular stomatitis virus (VSV) has been used as a gene expression vector, especially Indiana serotype (VSV(Ind)), but less with New Jersey serotype (VSV(NJ)). Here, we report constructions of genetically modified rVSV(NJ) vector carrying various lengths of human hepatitis C virus (HCV) non-structural (NS) protein genes, level of inserted gene expression and characterization of rVSV(NJ). We modified the M gene of VSV(NJ) by changing methionine to arginine at positions 48 and 51 (rVSV(NJ)-M) (Kim and Kang, 2007) for construction of rVSV(NJ) with various lengths of HCV non-structural genes. The NS polyprotein genes of HCV were inserted between the G and L genes of the rVSV(NJ)-M vector, and recombinant VSV(NJ)-M viruses with HCV gene inserts were recovered by the reverse genetics. The recombinant VSV(NJ)-M vector with the HCV NS genes express high levels of all different forms of the NS proteins. The electron microscopic examination showed that lengths of recombinant VSV(NJ)-M without gene of interests, VSV(NJ)-M with a gene of HCV NS3 and NS4A (VSV(NJ)-M-NS3/4A), VSV(NJ)-M with a gene of HCV NS4AB plus NS5AB (VSV(NJ)-M-NS4AB/5AB), and VSV(NJ)-M carrying a gene of HCV NS3, NS4AB, and NS5AB (VSV(NJ)-M-NS3/4AB/5AB) were 172±10.5 nm, 201±12.5 nm, 226±12.9 nm, and 247±18.2 nm, respectively. The lengths of recombinant VSVs increased approximately 10nm by insertion of 1kb of foreign genes. The diameter of these recombinant viruses also increased slightly by longer HCV gene inserts. Our results showed that the recombinant VSV(NJ)-M vector can accommodate as much as 6000 bases of the foreign gene. We compared the magnitude of the IFN induction in mouse fibroblast L(Y) cells infected with rVSV(NJ) wild type and rVSV(NJ) M mutant viruses and show that the rVSV(NJ) M mutant virus infection induced a higher level of the IFN-ß compare to the wild type virus. In addition, we showed that the NS protein expression level in IFN-incompetent cells (Mouse-L) infected with rVSV(NJ)-M viruses was higher than in IFN-competent L(Y) cells. In addition, we confirmed that HCV NS protein genes were expressed and properly processed. We also confirmed that NS3 protein expressed from the rVSV(NJ)-M cleaves NS polyprotein at junctions and that NS4A plays an important role as a co-factor for NS3 protease to cleave at the NS4B/5A site and at the NS5A/5B site.

Host predilection and transmissibility of vesicular stomatitis New Jersey virus strains in domestic cattle (Bos taurus) and swine (Sus scrofa).

BACKGROUND: Epidemiologic data collected during epidemics in the western United States combined with limited experimental studies involving swine and cattle suggest that host predilection of epidemic vesicular stomatitis New Jersey virus (VSNJV) strains results in variations in clinical response, extent and duration of virus shedding and transmissibility following infection in different hosts. Laboratory challenge of livestock with heterologous VSNJV strains to investigate potential viral predilections for these hosts has not been thoroughly investigated. In separate trials, homologous VSNJV strains (NJ82COB and NJ82AZB), and heterologous strains (NJ06WYE and NJOSF [Ossabaw Island, sand fly]) were inoculated into cattle via infected black fly bite. NJ82AZB and NJ06WYE were similarly inoculated into swine. RESULTS: Clinical scores among viruses infecting cattle were significantly different and indicated that infection with a homologous virus resulted in more severe clinical presentation and greater extent and duration of viral shedding. No differences in clinical severity or extent and duration of viral shedding were detected in swine. CONCLUSIONS: Differences in clinical presentation and extent and duration of viral shedding may have direct impacts on viral spread during epidemics. Viral transmission via animal-to-animal contact and insect vectored transmission are likely to occur at higher rates when affected animals are presenting severe clinical signs and shedding high concentrations of virus. More virulent viral strains resulting in more severe disease in livestock hosts are expected to spread more rapidly and greater distances during epidemics than those causing mild or inapparent signs.

A recombinant vesicular stomatitis virus bearing a lethal mutation in the glycoprotein gene uncovers a second site suppressor that restores fusion.

Vesicular stomatitis virus (VSV), a prototype of the Rhabdoviridae family, contains a single surface glycoprotein (G) that is responsible for attachment to cells and mediates membrane fusion. Working with the Indiana serotype of VSV, we employed a reverse genetic approach to produce fully authentic recombinant viral particles bearing lethal mutations in the G gene. By altering the hydrophobicity of the two fusion loops within G, we produced a panel of mutants, W72A, Y73A, Y116A, and A117F, that were nonfusogenic. Propagation of viruses bearing those lethal mutations in G completely depended on complementation by expression of the glycoprotein from the heterologous New Jersey serotype of VSV. The nonfusogenic G proteins oligomerize and are transported normally to the cell surface but fail to mediate acid pH-triggered membrane fusion. The nonfusogenic G proteins also interfered with the ability of wild-type G to mediate fusion, either by formation of mixed trimers or by inhibition of trimer function during fusion. Passage of one recombinant virus, A117F, identified a second site suppressor of the fusion block, E76K. When analyzed in the absence of the A117F substitution, E76K rendered G more sensitive to acid pH-triggered fusion, suggesting that this compensatory mutation is destabilizing. Our work provides a set of authentic recombinant VSV particles bearing lethal mutations in G, confirms that the hydrophobic fusion loops of VSV G protein are critical for membrane fusion, and underscores the importance of the sequence elements surrounding the hydrophobic tips of the fusion loops in driving fusion. This study has implications for understanding dominant targets for inhibition of G-mediated fusion. Moreover, the recombinant viral particles generated here will likely be useful in dissecting the mechanism of G-catalyzed fusion as well as study steps of viral assembly.

Comparison of RNA extraction methods to augment the sensitivity for the differentiation of vesicular stomatitis virus Indiana1 and New Jersey.

Two methods for the extraction of RNA of vesicular stomatitis virus (VSV) Indiana1 and New Jersey and their simultaneous amplification by one-step polymerase chain reaction using reverse transcriptase were evaluated. A guanidine-thiocyanate-based RNA extraction (Qiagen RNeasy Mini Kit, Qiagen, Valencia, CA ) followed by column-based purification coupled with one-step RT-PCR proved to be a simple, safe, practicable, and reliable tool for rapid, highly sensitive, and specific differential diagnosis of both types of VSV in cell lysate and spiked tissue samples as compared with the tri-phasic extraction method (Tri-reagent method). When RNA was extracted either from VSV cell culture stock or from VSV spiked bovine lymph nodes by using Qiagen RNeasy Mini Kit, the detection limit in the multiplex RT-PCR was as low as 0.505 to 2.84 TCID(50) for VSV-IND and VSV-NJ, respectively. The multiplex RT-PCR consistently detected VSV-IND and NJ RNA in as little as 0.1-1.0 fg of total RNA from spiked BHK-21 cell suspension when Qiagen RNeasy mini kit was used. The multiplex RT-PCR assay was capable of detecting both types of VSV in a one-step reaction tube. The minimum sensitivity of this assay in various experiments was 0.1683 TCID(50) (IND), 0.0946 TCID(50) (NJ), and 0.057 fg (IND and NJ) per 2 µl PCR sample, which is significantly more sensitive than reported previously (0.28-2.8 TCID50/1 µl). So the present study improved the sensitivity of previously reported multiplex RT-PCR for the detection and differentiation of VSV-IND and VSV-NJ in a single assay.

Apparent disappearance of Vesicular Stomatitis New Jersey Virus from Ossabaw Island, Georgia.

Ossabaw Island, Georgia, is the only reported endemic focus of Vesicular Stomatitis New Jersey Virus (VSNJV) in the United States. Based on recent negative serologic results of white-tailed deer and feral swine and the failure to isolate VSNJV from Lutzomyia shannoni, it appears that VSNJV is no longer present at this site. This apparent disappearance does not appear to be related to a change in L. shannoni habitat, specifically to the density of tree holes in the maritime and mixed hardwood forests. We believe that the disappearance of VSNJV from Ossabaw Island is directly related to a reduction in the feral swine population and a subsequent increase in the utilization of white-tailed deer by the known vector, L. shannoni.

Improvement and optimization of a multiplex real-time reverse transcription polymerase chain reaction assay for the detection and typing of Vesicular stomatitis virus.

An improvement to a previously reported real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assay for the detection of Vesicular stomatitis virus (VSV) is described. Results indicate that the new assay is capable of detecting a panel of genetically representative strains of VSV present in North, Central, and South America. The assay is specific for VSV and allows for simultaneous differentiation between Vesicular stomatitis Indiana virus and Vesicular stomatitis New Jersey virus. This real-time RT-PCR is able to detect current circulating strains of VSV and can be used for rapid diagnosis of VSV and differentiation of VSV from other vesicular diseases, such as foot-and-mouth disease.

Field evaluation of a multiplex real-time reverse transcription polymerase chain reaction assay for detection of Vesicular stomatitis virus.

Sporadic outbreaks of vesicular stomatitis (VS) in the United States result in significant economic losses for the U.S. livestock industries because VS is a reportable disease that clinically mimics foot-and-mouth disease. Rapid and accurate differentiation of these 2 diseases is critical because their consequences and control strategies differ radically. The objective of the current study was to field validate a 1-tube multiplexed real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assay for the rapid detection of Vesicular stomatitis New Jersey virus and Vesicular stomatitis Indiana virus strains occurring in Mexico and North and Central America. A comprehensive collection of 622 vesicular lesion samples obtained from cattle, horses, and swine from throughout Mexico and Central America was tested by the real-time RT-PCR assay and virus isolation. Overall, clinical sensitivity and specificity of the real-time RT-PCR were 83% and 99%, respectively. Interestingly, VS virus isolates originating from a specific region of Costa Rica were not detected by real-time RT-PCR. Sequence comparisons of these viruses with the real-time RT-PCR probe and primers showed mismatches in the probe and forward and reverse primer regions. Additional lineage-specific primers and a probe corrected the lack of detection of the missing genetic lineage. Thus, this assay reliably identified existing Mexican and Central American VS viruses and proved readily adaptable as new VS viruses were encountered. An important secondary result of this research was the collection of hundreds of new VS virus isolates that provide a foundation from which many additional studies can arise.

[Expressing of N gene encoding nucleocapsid protein of vesicular stomatitis virus and elementary application in ELISA].

The gene encoding the nucleocapsid (N) protein of vesicular stomatitis virus (VSV-NJ) was subcloned from pMD-VN5, and inserted into pBAD/Thio TOPO vector. The recombinant plasmid was identified by restriction analysis and PCR. It was sequenced to confirm the correct sequences and the correct junctional orientations of the inserted N gene. The results of SDS-PAGE and Western immunoblotting revealed that the N protein was expressed in Escherichia coli LGM194 in a high level and the recombinant fusion protein, which contained a N-terminal HP-Thioredoxin and a C-terminal polyhistidine tag. It had a molecular mass of approximately 63.5 kD and immunologically reactive activity. The recombinant protein was characterized and tested in an enzyme-linked immunosorbent assay (ELISA) format for potential application in the serodiagnosis of vesicular stomatitis using 186 serum samples from experimentally infected goats and guinea-pigs with VSV-NJ and VSV-IN, and from field origin and reference serum samples. The sensitivity and specificity of the ELISA were compared with those of the standard microtiter serum neutralization (MTSN) tests. The ELISA and MTSN test results were highly correlated for detection of VSV antibodies. The ELISA was as sensitive as the SN assay in detecting positive serum to VSV. The correlation between SN titers and ELISA titers was statistically significant. These data suggest that the recombinant fusion N protein of VSV could be used as a recombinant test antigen for the serodiagnosis of vesicular stomatitis. The ELISA based on the reconmbinant nucleocapsid protein may offer the best combination of rapidity, sensitivity, simplicity, economy, and laboratory biosafety of any of the methods yet developed for VSV serodiagnosis. This study lay on foundation for the development of the diagnosis methods in serology for VSV.