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In this communication, we report the presence of RNA of bovine viral diarrhea virus (BVDV) as a contaminant of different biological products used in Mexico for veterinary vaccine production. For this purpose, six batches of monovalent vaccines, eight cell line batches used for vaccine production, and 10 fetal bovine serum lots (FBS) commercially available in Mexico from different suppliers were tested by reverse transcription polymerase chain reaction (RT-PCR). Viral RNA was detected in 62.5% of the samples analyzed. Phylogenetic analysis revealed the presence of the subgenotypes BVDV-1a, 1b, and BVDV-2a in the tested samples. Collectively, these findings indicate that contamination by BVDV RNA occurs in commercial vaccines and reagents used in research and production of biological products. The ramifications of this contamination are discussed.

Bovine coronaviruses (BoCVs) have been found in respiratory tissues in cattle and frequently associated with bovine respiratory disease (BRD); however, pathogenesis studies in calves are limited. To characterize the pathogenesis and pathogenicity of BoCV isolates, we used 5 different BoCV strains to inoculate colostrum-deprived calves, ~ 2–5 wk of age. Later, to determine if dual viral infection would potentiate pathogenicity of BoCV, calves were inoculated with BoCV alone, bovine viral diarrhea virus (BVDV) alone, or a series of dual-infection (BVDV–BoCV) schemes. A negative control group was included in all studies. Clinical signs and body temperature were monitored during the study and samples collected for lymphocyte counts, virus isolation, and serology. During autopsy, gross lesions were recorded and fixed tissues collected for histopathology and immunohistochemistry; fresh tissues were collected for virus isolation. Results suggest increased pathogenicity for isolate BoCV OK 1776. Increased body temperature was found in all virus-inoculated groups. Lung lesions were present in calves in all dual-infection groups; however, lesions were most pronounced in calves inoculated with BVDV followed by BoCV inoculation 6 d later. Lung lesions were consistent with mild-to-moderate interstitial pneumonia, and immunohistochemistry confirmed the presence of BoCV antigen. Our studies demonstrated that BVDV–BoCV dual infection may play an important role in BRD pathogenesis, and timing between infections seems critical to the severity of lesions.

Bovine viral diarrhea (BVD) is an infectious disease, globally-distributed, caused by bovine Pestiviruses, endemic of cattle and other ruminant populations. BVD leads to significant economic losses to the cattle industry due to the wide range of clinical manifestations, including respiratory and gastrointestinal diseases and reproductive disorders. Within the Pestivirus genus of the family Flaviviridae three viral species are associated with BVD; Pestivirus A (Bovine viral diarrhea virus 1, BVDV-1), Pestivirus B (Bovine viral diarrhea virus 2, BVDV-2), and Pestivirus H (HoBi-like pestivirus, atypical ruminant pestivirus). These species are subdivided into subgenotypes based on phylogenetic analysis. The extensive genetic diversity of BVDV has been reported for several countries, where the incidence and genetic variation are more developed in Europe than in the Americas. The first report of BVDV in Mexico was in 1975; this study revealed seropositivity of 75% in cows with a clinical history of infertility, abortions, and respiratory disease. Other studies have demonstrated the presence of antibodies against BVDV with a seroprevalence ranging from 7.4 to 100%. Recently, endemic BVDV strains affecting cattle populations started to be analyzed, providing evidence of the BVDV diversity in several states of the country, revealing that at least four subgenotypes (BVDV-1a, 1b, 1c, and 2a) are circulating in animal populations in Mexico. Little information regarding BVD epidemiological current status in Mexico is available. This review summarizes available information regarding the prevalence and genetic diversity viruses associated with BVD in cattle from Mexico.

This study examined the effects of multivalent respiratory vaccine treatment (VT) and animal temperament classification on feeding behavior traits, feed intake and animal performance in response to a bovine viral diarrhea virus (BVDV) challenge. Nellore–Angus crossbred steers (n = 360, initial body weight (BW) 330 ± 48 kg) were assigned to one of three vaccine treatments: non-vaccinated (NON), modified live (MLV) and killed (KV) regarding respiratory viral pathogens, and inoculated intranasally with the same BVDV1b strain. Cattle temperament categories were based on exit velocity. Overt clinical signs of respiratory disease were not observed, yet the frequency and duration of bunk visit events as well as traditional performance traits decreased (p &lt, 0.01) following BVDV challenge and then rebounded in compensatory fashion. The reduction in dry matter intake (DMI) was less (p &lt, 0.05) for MLV-vaccinated steers, and MLV-vaccinated steers had longer (p &lt, 0.01) durations of bunk visit and meal events and slower (p &lt, 0.01) eating rates compared with KV- and non-vaccinated steers following BVDV challenge. Greater differences in most feeding behavior traits due to VT existed within calm vs. excitable steers. Respiratory vaccination can reduce the sub-clinical feeding behavior and performance effects of BVDV in cattle, and the same impacts may not occur across all temperament categories.

Along with viruses in the Pestivirus A (Bovine Viral Diarrhea Virus 1, BVDV1) and B species (Bovine Viral Diarrhea Virus 2, BVDV2), members of the Pestivirus H are mainly cattle pathogens. Viruses belonging to the Pestivirus H group are known as HoBi-like pestiviruses (HoBiPev). Genetic and antigenic characterization suggest that HoBiPev are the most divergent pestiviruses identified in cattle to date. The phylogenetic analysis of HoBiPev results in at least five subgroups (a–e). Under natural or experimental conditions, calves infected with HoBiPev strains typically display mild upper respiratory signs, including nasal discharge and cough. Although BVDV1 and BVDV2 are widely distributed and reported in many South American countries, reports of HoBiPev in South America are mostly restricted to Brazil. Despite the endemicity and high prevalence of HoBiPev in Brazil, only HoBiPev-a was identified to date in Brazil. Unquestionably, HoBiPev strains in BVDV vaccine formulations are required to help curb HoBiPev spread in endemic regions. The current situation in Brazil, where at this point only HoBiPev-a seems present, provides a more significant opportunity to control these viruses with the use of a vaccine with a single HoBiPev subtype. Despite the lack of differentiation among bovine pestiviruses by current BVDV tests, the reduced genetic variability of HoBiPev in Brazil may allow reliable identification of cases within the region. On the other hand, introducing foreign ruminants, biologicals, and genetic material to South America, especially if it originated from other HoBiPev-endemic countries, should consider the risk of introducing divergent HoBiPev subtypes.

Antigenic differences between bovine viral diarrhea virus (BVDV) vaccine strains and field isolates can lead to reduced vaccine efficacy. Historically, antigenic differences among BVDV strains were evaluated using techniques based on polyclonal and monoclonal antibody activity. The most common method for antigenic comparison among BVDV isolates is determination of virus neutralization titer (VNT). BVDV antigenic comparisons using VNT only account for the humoral component of the adaptive immune response, and not cell mediated immunity (CMI) giving an incomplete picture of protective responses. Currently, little data is available regarding potential antigenic differences between BVDV vaccine strains and field isolates as measured by CMI responses. The goal of the current paper is to evaluate two groups of cattle that differed in the frequency they were vaccinated, to determine if similar trends in CMI responses exist within each respective group when stimulated with antigenically different BVDV strains. Data from the current study demonstrated variability in the CMI response is associated with the viral strain used for stimulation. Variability in IFN-γ mRNA expression was most pronounced in the CD4+ population, this was observed between the viruses within each respective BVDV subgenotype in the Group 1 calves. The increase in frequency of CD25+ cells and IFN-γ mRNA expression in the CD8+ and CD335+ populations were not as variable between BVDV strains used for stimulation in the Group 1 calves. Additionally, an inverse relationship between VNT and IFN-γ mRNA expression was observed, as the lowest VNT and highest IFN-γ mRNA expression was observed and vice versa, the highest VNT and lowest IFN-γ mRNA expression was observed. A similar trend regardless of vaccination status was observed between the two groups of calves, as the BVDV-1b strain had lower IFN-γ mRNA expression. Collectively, data from the current study and previous data support, conferring protection against BVDV as a method for control of BVDV in cattle populations is still a complex issue and requires a multifactorial approach to understand factors associated with vaccine efficacy or conversely vaccine failure. Although, there does appear to be an antigenic component associated with CMI responses as well as with humoral responses as determined by VNT.

Bovine viral diarrhea viruses (BVDV) are significant pathogens of cattle, leading to losses associated with reproductive failure, respiratory disease and immune dysregulation. While cattle are the reservoir for BVDV, a wide range of domestic and wild ruminants are susceptible to infection and disease caused by BVDV. Samples from four American bison (Bison bison) from a captive herd were submitted for diagnostic testing due to their general unthriftiness. Metagenomic sequencing on pooled nasal swabs and serum identified co-infection with a BVDV and a bovine bosavirus. The BVDV genome was more similar to the vaccine strain Oregon C24 V than to other BVDV sequences in GenBank, with 92.7 % nucleotide identity in the open reading frame. The conserved 5'-untranslated region was 96.3 % identical to Oregon C24 V. Bosavirus has been previously identified in pooled fetal bovine serum but its clinical significance is unknown. Sequencing results were confirmed by virus isolation and PCR detection of both viruses in serum and nasal swab samples from two of the four bison. One animal was co-infected with both BVDV and bosavirus while separate individuals were positive solely for BVDV or bosavirus. Serum and nasal swabs from these same animals collected 51 days later remained positive for BVDV and bosavirus. These results suggest that both viruses can persistently infect bison. While the etiological significance of bosavirus infection is unknown, the ability of BVDV to persistently infect bison has implications for BVDV control and eradication programs. Possible synergy between BVDV and bosavirus persistent infection warrants further study.

The objective of this study was to compare immunological responses and lymphoid depletion in young, colostrum deprived calves following administration of vaccines containing modified-live bovine viral diarrhea virus (BVDV). A group of calves exposed to a typical virulence non-cytopathic (ncp) BVDV-2 field strain (ncp exposed) was included to compare responses of calves receiving vaccine to responses generated against a field strain (mimicking a natural infection). A negative control group administered a placebo was used in all comparisons. All vaccines used in the study were administered per manufacturer recommendations while ncp BVDV exposed calves received 5 ml intranasally (2.5 ml/nare; 4.2 × 106 TCID50/ml) of the BVDV-2 field strain. Samples collected at each time point included nasal swabs for virus detection, blood samples for complete blood counts and detection of viremia, PBMCs for flow cytometric analysis, serum for virus neutralization titers, and thymus tissue at necropsy for evaluation of lymphoid depletion. A measurable neutralizing BVDV titer was observed for all treatment groups excluding the control animals, which remained negative during the study period. Virus shedding was only detected from the ncp vaccinated and ncp exposed calves. A decline from baseline was observed for peripheral lymphocyte and CD4+ cells for the groups receiving the adjuvanted cytopathic (cp) vaccine, the double deleted genetically modified (ddGM) vaccine, the ncp vaccine and ncp exposed calves, but not for the control group or groups receiving cp vaccines. Thymus depletion was observed for the ncp vaccine and ncp exposed calves and to a lesser extent for the ddGM vaccine calves. Collectively, these data suggest that the virus biotype, method of attenuation, presentation, and use of adjuvant will influence vaccine impacts on lymphoid tissues and the immune response. As such, multiple variables should be considered when determining costs and benefits of vaccination.

Bovine viral diarrhea viruses (BVDV) cause acute and persistent infections. Acute infection results in generalized immunosuppression characterized by a decrease in circulating lymphocytes as a result of depletion of CD4+ and CD8 + T cell populations. Persistent infection with BVDV is the result of immune tolerance and is generally not associated with lymphocytopenia. The health outcome of persistently infected (PI) calves varies widely; some die of mucosal disease, some succumb to ill thrift and others appear normal and survive to adulthood. Detection of BVDV at the single lymphoid cell level is important to the study of subpopulations of peripheral blood mononuclear cells (PBMC) during BVDV infections, however there are few methods available for the detection and quantification of BVDV at this level. To circumvent this difficulty, a novel flow cytometry-based PrimeFlow RNA assay using in-situ detection of BVDV was developed. This assay was used to evaluate differences in viral distribution within subpopulations of PBMC over time in PI calves carrying one of two different species of BVDV (type 1 and type 2). Calves were sampled at 3 different time points approximately one month apart. During the course of the study, a subset of the calves died from ill thrift. Mucosal disease was not indicated in any of the deaths. Using RNA probes specific for the BVDV Npro-Erns coding regions for each respective virus, BVDV RNA was detected in all PBMC of PI that appeared clinically healthy. Calves that succumbed to ill thrift were found to have no or little virus in T cells. The clearance of virus from T cells suggests a breakdown in immune tolerance in these calves. This is the first report of a pattern observed in the viral load in the T cell subpopulations and survival in PI calves.

The significant economic impacts of bovine viral diarrhoea (BVD) virus have prompted many countries worldwide to embark on regional or national BVD eradication programmes. Unlike other infectious diseases, BVD control is highly feasible in cattle production systems because the pathogenesis is well understood and there are effective tools to break the disease transmission cycle at the farm and industry levels. Coordinated control approaches typically involve directly testing populations for virus or serological screening of cattle herds to identify those with recent exposure to BVD, testing individual animals within affected herds to identify and eliminate persistently infected (PI) cattle, and implementing biosecurity measures such as double-fencing shared farm boundaries, vaccinating susceptible breeding cattle, improving visitor and equipment hygiene practices, and maintaining closed herds to prevent further disease transmission. As highlighted by the recent DISCONTOOLS review conducted by a panel of internationally recognized experts, knowledge gaps in the control measures are primarily centred around the practical application of existing tools rather than the need for creation of new tools. Further research is required to: (a) determine the most cost effective and socially acceptable means of applying BVD control measures in different cattle production systems; (b) identify the most effective ways to build widespread support for implementing BVD control measures from the bottom-up through farmer engagement and from the top-down through national policy; and (c) to develop strategies to prevent the reintroduction of BVD into disease-free regions by managing the risks associated with the movements of animals, personnel and equipment. Stronger collaboration between epidemiologists, economists and social scientists will be essential for progressing efforts to eradicate BVD from more countries worldwide.

Bovine viral diarrhea virus (BVDV) infections, whether as acute, persistent or contributing to co-infections, result in significant losses for cattle producers. Although, BVDV can be identified readily by real-time PCR and ELISA, detection and quantification of viral infection at the single cell level is extremely difficult. Detection at the single lymphoid cell level is important due to the immunomodulation that accompanies BVDV infection. A novel PrimeFlow RNA assay using in-situ detection of BVDV was evaluated. The model used to develop this technique included three BL-3 cell lines with different infection statuses, one not infected with BVDV, one infected with BVDV and one dual infected with BVDV and bovine leukosis virus. Using RNA probes specific for the BVDV-2a Npro-Erns coding region, BVDV RNA was detected from both contaminated BL-3 cell lines by flow cytometry and fluorescent microscopy. This is the first report on in-situ detection of BVDV at the single-cell level.

Naive 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.

The genus Pestivirus within Flaviviridae is comprised of four recognized species, namely, bovine viral diarrhoea virus 1 (BVDV-1), bovine viral diarrhoea virus 2 (BVDV-2), border disease virus (BDV) and classical swine fever virus (CSFV). BDV, while primarily infecting sheep and goats, has also been reported in cattle and wild animals. Infections of sheep and goats result in economic loss due to abortions and the birth of persistently infected animals that have poor production and reduced life expectancy. In this study, we report the detection of BDV in cattle serum collected as part of pestivirus surveillance programme from six regions of Mexico, where a 67.1% of BVDV seroprevalence was calculated previously. Phylogenetic analyses based on comparison of the 5'UTR region typed the Mexican strains as BDV-1. Border disease (BD) is listed as an exotic disease in Mexico, and the origin of BDV found in these cattle is unclear. This is the first identification of BDV in Mexican cattle.

Influenza D virus has been detected predominantly in cattle from several countries. In the United States, regional and state seropositive rates for influenza D have previously been reported, but little information exists to evaluate national seroprevalence. We performed a serosurveillance study with 1,992 bovine serum samples collected across the country in 2014 and 2015. We found a high overall seropositive rate of 77.5% nationally; regional rates varied from 47.7% to 84.6%. Samples from the Upper Midwest and Mountain West regions showed the highest seropositive rates. In addition, seropositive samples were found in 41 of the 42 states from which cattle originated, demonstrating that influenza D virus circulated widely in cattle during this period. The distribution of influenza D virus in cattle from the United States highlights the need for greater understanding about pathogenesis, epidemiology, and the implications for animal health.

Serological evidence suggests that HoBi-like viruses, an emerging species within the Pestivirus genus of the Flaviviridae family, are in circulation in Argentina. While HoBi-like viruses were first isolated from Brazilian fetal bovine serum (FBS), no survey of Argentine FBS has been conducted. Therefore, 124 local samples of non-irradiated FBS originating from Argentina were surveyed for the presence of pestiviruses using RT-PCR. Amplicons from pestivirus positive samples were genotyped. Four samples were positive for HoBi virus-specific RT-PCR, while the BVDV-positive samples (n = 45) were classified as BVDV-1b (82.2%), BVDV-1a (13.3%), and BVDV-2 (4.5%). Virus isolation and serological profile assessment were performed for the four HoBi-positive FBS lots. These results confirm the circulation of HoBi-like virus in some regions of the Argentinean territory, highlighting the need to review the diagnostic techniques currently used in the clinical cases suspected of BVDV and in contamination control protocols for adventitious agents in cells and biotechnological products. Fil: Pecora, Andrea. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Virologia E Innovaciones Tecnologicas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Virologia E Innovaciones Tecnologicas.; Argentina Fil: Pérez Aguirreburualde, María Sol. University of Minnesota; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ridpath, Julia Francis. No especifíca; Fil: Dus Santos, María José. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Virologia E Innovaciones Tecnologicas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Virologia E Innovaciones Tecnologicas.; Argentina

Four species of ruminant pestivirus are currently circulating in the United States: Bovine viral diarrhea virus 1 and 2 (BVDV-1, -2; predominant host: cattle), Border disease virus (BDV; predominant host: sheep), and pronghorn virus (sporadically detected in wild ruminants). A third bovine pestivirus called HoBi-like virus has been detected in cattle and water buffalo in South America, Asia, and Europe. To date, no isolations of HoBi-like viruses from U.S. cattle have been reported. To assess exposure, 2,000 cattle sera, collected between 2014 and 2015 as part of the U.S. brucellosis surveillance program, were tested for antibodies against BVDV-1, BVDV-2, and HoBi-like viruses. In addition, RNA was extracted and tested by reverse transcription–polymerase chain reaction for the presence of pestiviruses; all samples tested negative. The percent of VN-positive samples was 91.3% for BVDV-1, 89.3% for BVDV-2, and 84.9% for HoBi-like viruses. Because the 3 bovine pestiviruses are antigenically cross-reactive, the comparative level of antibody against each pestivirus species was determined. Based on comparative titers, samples were segregated into 6 categories: no titers (7.6%), titers clearly higher against BVDV-1 (22.2%), titers substantially higher against BVDV-2 (9.1%), BVDV-1 and BVDV-2 titers equivalent but substantially higher than HoBi titers (25.7%), titers substantially higher against HoBi-like viruses (0%), and equivocal (35.4%). Titers tended to be higher against BVDV-1 than BVDV-2. However, the overall percentage of animals with titers below levels considered protective against acute bovine pestivirus infection were ~11% for BVDV-1, 12% BVDV-2, and 18% for HoBi-like virus.

'HoBi'-like virus is an atypical group within the Pestivirus genus that is implicated in economic losses for cattle producers due to both acute and persistent infections. Pestivirus strains exist as quasispecies (swarms of individual viruses) in infected animals and the viral populations making up the quasispecies differ widely in size and diversity in each animal. In the present study the viral quasispecies circulating in persistently infected (PI) calves, generated and maintained under experimental conditions using two different 'HoBi'-like strains, was observed over time. An increase in genetic variability and the development of certain mutations was observed over time. Mutations observed included the loss of a putative N-linked glycosylation site in the E2 region and the change of specific residues in E1/E2. It is hypothesized that these changes may be the results on continued adaption of the pestivirus to individual hosts. This is the first study characterizing variation in the viral swarms of animals persistently infected with HoBi-like viruses over time. Studies of the shifts in PI viral swarms will contribute to our understanding of the host and viral mechanisms that function in the maintenance of pestivirus persistent infections.

The causes of bovine respiratory disease complex (BRDC) are multifactorial and include infection with both viral and bacterial pathogens. Host factors are also involved as different breeds of cattle appear to have different susceptibilities to BRDC. Infection with bovine pestiviruses, including bovine viral diarrhea virus 1 (BVDV1), BVDV2 and 'HoBi'-like viruses, is linked to the development of BRDC. The aim of the present study was to compare the growth of different bovine pestiviruses in primary testicle cell cultures obtained from taurine, indicine and mixed taurine and indicine cattle breeds. Primary cells strains, derived from testicular tissue, were generated from three animals from each breed. Bovine pestivirus strains used were from BVDV-1a, BVDV-1b, BVDV-2a and 'HoBi'-like virus. Growth was compared by determining virus titers after one passage in primary cells. All tests were run in triplicate. Virus titers were determined by endpoint dilution and RT-qPCR. Statistical analysis was performed using one way analysis of variance (ANOVA) followed by the Tukey's Multiple Comparison Test (P˂0.05). Significant differences in virus growth did not correlate with cattle breed. However, significant differences were observed between cells derived from different individuals regardless of breed. Variation in the replication of virus in primary cell strains may reflect a genetic predisposition that favors virus replication.

Subclinical illness associated with infection is thought to reduce performance and increase production costs in feedlot cattle, but underlying components remain largely unidentified. Vaccination is frequently used in feedlot settings but producers lack metrics that evaluate the effectiveness of vaccination programs. The goal of this study was to determine if levels of serum neutralizing antibody titers were predictive of levels of vaccine protection in a commercial setting. During this four-year study, Angus-Nellore steers housed in a production feedlot setting were assigned to 1 of 3 vaccine treatments: killed vaccine (kV), modified live virus (MLV) vaccine, or no vaccine (control), and were challenged with a noncytopathic 1b field strain of bovine viral diarrhea virus. Rectal temperature and levels of circulating lymphocytes and platelets were monitored following challenge. While no animals were diagnosed as clinically ill with respiratory disease, indicators of disease (pyrexia, lymphopenia, and thrombocytopenia) were observed. The MLV treatment elicited higher antibody titers to the vaccination than the kV, and calves in the MLV treatment had higher mean titers at challenge. The year that elicited the highest antibody response to the vaccination and the year with the lowest frequency of phenotypic responses to the challenge were not concurrent. The MLV treatment had the highest proportion, 34.68%, of animals that were protected against the challenge regardless of the pre-challenge antibody titer and had the fewest number of lymphopenia cases in response to the challenge. Both vaccine treatments mitigated thrombocytopenia when compared to the control treatment, and the MLV treatment reduced lymphopenia; however, these symptoms were not completely eliminated in vaccinated animals. Pyrexia was present in 40.11% of the animals, but no difference in the frequency of cases between treatments was observed. Pre-challenge vaccination response was not indicative of the level of protection nor was anamnestic antibody response correlated with health status.

This study investigated viruses in bovine respiratory disease (BRD) cases in feedlots, including bovine herpesvirus-1 (BoHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine coronaviruses (BoCV) and parainfluenza-3 virus (PI3V). Nasal swabs were collected from 114 cattle on initial BRD treatment. Processing included modified live virus (MLV) vaccination. Seven BRD necropsy cases were included for 121 total cases. Mean number of days on feed before first sample was 14.9 days. Swabs and tissue homogenates were tested by gel based PCR (G-PCR), quantitative-PCR (qPCR) and quantitative real time reverse transcriptase PCR (qRT-PCR) and viral culture. There were 87/114 (76.3%) swabs positive for at least one virus by at least one test. All necropsy cases were positive for at least one virus. Of 121 cases, positives included 18/121 (14.9%) BoHV-1; 19/121 (15.7%) BVDV; 76/121 (62.8%) BoCV; 11/121 (9.1%) BRSV; and 10/121 (8.3%) PI3V. For nasal swabs, G-PCR (5 viruses) detected 44/114 (38.6%); q-PCR and qRT-PCR (4 viruses) detected 81/114 (71.6%); and virus isolation detected 40/114 (35.1%). Most were positive for only one or two tests, but not all three tests. Necropsy cases had positives: 5/7 G-PCR, 5/7 q-PCR and qRT-PCR, and all were positive by cell culture. In some cases, G-PCR and both real time PCR were negative for BoHV-1, BVDV, and PI3V in samples positive by culture. PCR did not differentiate field from vaccines strains of BoHV-1, BVDV, and PI3V. However based on sequencing and analysis, field and vaccine strains of culture positive BoHV-1, BoCV, BVDV, and PI3V, 11/18 (61.1%) of BoHV-1 isolates, 6/17 (35.3%) BVDV isolates, and 1/10 (10.0%) PI3V identified as vaccine. BRSV was only identified by PCR testing. Interpretation of laboratory tests is appropriate as molecular based tests and virus isolation cannot separate field from vaccine strains. Additional testing using sequencing appears appropriate for identifying vaccine strains.

Infection with bovine leukemia virus (BLV) results in economic loss because of reduced productivity, especially reduced milk production, and early culling. In the United States, studies in 1996, 1999, and 2007 showed BLV infection to be widespread, especially in dairy herds. We updated information herein on BLV seroprevalence in the United States, using samples submitted for testing and found negative for antibodies for Brucella by the Kentucky Eastern Regional Federal Brucellosis Laboratory. From October 2014 through August 2015, 2,000 samples from all regions of the contiguous United States were selected and tested for BLV antibodies by enzyme-linked immunosorbent assay. The overall percentage of samples positive for BLV antibody was 38.6%. Based on the animal’s origin, the percent positive by region ranged from 32.5% (Mountain West region) to 54.3% (Northeast region; p < 0.05). The positive rate for slaughter plants that processed mainly dairy animals (dairy plants; 47.6%) was higher than the positive rate at slaughter plants that processed mainly beef animals (beef plants; 33.6%; p < 0.05). The results suggest that BLV infection remains widespread in all regions of the United States and that rates may differ between beef and dairy cattle.

The pestiviruses bovine viral diarrhea virus 1 (BVDV-1), 2 (BVDV-2), and HoBi-like (HoBiPeV) are endemic among Brazilian cattle, the world's largest commercial bovine herd. In the last two decades (1998–2018) over 300 bovine pestiviruses have been partially or fully sequenced in Brazil, including viruses from different regions, different epidemiological backgrounds, and associated with diverse clinical presentations. Phylogenetic analysis of these viruses demonstrated a predominance of BVDV-1 (54.4%), with subgenotypes −1a (33.9% of total) and −1b (16.3%) being more frequent and subgenotypes −1d, −1e, and −1i at very low frequencies. The overall BVDV-2 frequency was 25.7% but it varied largely by region, reaching up to 48% in Southern states. BVDV-2b was the predominant subgenotype (84.8% of BVDV-2), followed by BVDV-2a (8.86%). HoBiPeV accounted for 19.9% (61/307) of the genotyped viruses and were detected at high frequency in cattle from Northeastern states. These findings demonstrate a unique mix of pestivirus species and subgenotypes, unlike that seen in Europe or North America. The design of effective diagnostic tools, vaccines, and control programs for limiting bovine pestivirus infections in Brazil must take into consideration this unique mix of viruses. This article provides a critical review of two decades of genetic identification of pestiviruses in Brazil.

Current methods for evaluating bovine viral diarrhea virus (BVDV) vaccination response typically rely on measurement of humoral responses as determined by virus neutralizing antibody titers (VNT) against BVDV. While VNT are correlated with increased protection, research has also shown that cell mediated immunity (CMI) is an important component of a protective response against BVDV. For example, improved protection against BVDV by modified-live viral (MLV) vaccines as compared to killed vaccines is thought to be due to better CMI induced by the MLV. The goal of this work was to evaluate the cell mediated response in vaccinated calves using a novel PrimeFlow RNA assay that incorporates cell surface marker staining with intracellular RNA expression of cytokines and viral RNA detection. Results from this study evaluating mRNA for IFN-γ and IL-2 at 24 h post-BVDV stimulation are similar to previous studies in which IFN-γ was detected in the CD4+ and CD8+ T cell population. However, a novel observation was the detection of IFN-γ mRNA in the NK cell population in vaccinated animals. The NK cell population contributed a significant portion of the IFN-γ produced. This study also demonstrated a decrease in the frequency and amount of BVDV in PBMCs, harvested from vaccinated calves and exposed to BVDV in vitro. Collectively data from this study highlights the association between an increase in IFN-γ and a decreased infection rate of isolated PBMC's, based on the frequency and amount of BVDV positive cells following in vitro exposure. This new method combines not only the ability to evaluate cellular responses, but also the ability to understand potential antiviral properties associated with cellular responses. This is the first assay to describe and simultaneously measure CMI responses and intracellular viral RNA quantity as a method to evaluate protective responses associated with vaccination.

Mycoplasma bovis, a frequent contributor to polymicrobial respiratory disease in cattle, has recently emerged as a major health problem in North American bison. Strong circumstantial evidence suggests it can be the sole pathogen causing disease manifestations in outbreaks of mortality in bison, but direct evidence is lacking. The goal of this study was to compare clinical signs and lesions in bison and cattle experimentally infected with field isolates of M. bovis recovered from bison. Bison (n = 7) and cattle (n = 6), seronegative for anti-M. bovis IgG, were exposed intranasally to M. bovis and necropsied 4–6 weeks later. Blood and nasal swabs were collected on day 0 (before exposure), day 11 and at necropsy. Samples of lung, lymph node, liver and spleen were also collected at necropsy. The only clinical sign observed was an elevation in the core body temperature of bison during the first few weeks post-exposure. Grossly visible lesions were apparent at necropsy in the lungs of five bison and the lymph node of one bison, while none were evident in cattle. Histologic evaluation revealed moderate to severe pulmonary lesions in four bison but none in cattle. M. bovis was recovered from tissues demonstrating gross lesions and from the lymph nodes of one additional bison and two cattle. All animals seroconverted by the time of necropsy. These data provide the first direct evidence that M. bovis can be a sole or primary cause of respiratory disease in healthy bison, although the isolates used were unable to cause disease in healthy cattle.

HoBi-like viruses are an emerging species of pestiviruses associated with respiratory and reproductive disease in cattle and in water buffaloes. Although cattle appear to be the main natural hosts, little is know about the potential for HoBi-like viruses to be transmitted to other livestock. In this study, seronegative calves, goats and pigs, and sheep harboring pestivirus antibodies (probably due to previous exposure to BVDV) were exposed to HoBi-like viruses either by direct inoculation (GIn) or by contact with calves persistently infected with HoBi-like viruses (GEx). Both GIn and GEx groups were monitored for clinical signs, lymphocyte count, virus in buffy coats and nasal swabs up to day 18 post-inoculation (pi). Evidence of transmission of HoBi-like virus by PI calves was observed in all studied species. No difference in clinical presentation was observed between animals in the GIn or GEx groups. Evidence of infection, depending on the species included lymphocyte depletion, fever, viral RNA detection, and/or seroconversion. Depletion of lymphocytes was observed in calves and goats (35% and 50%, respectively) but not in pigs. Seroconversion was observed in at least one animal of each group and for all exposed species. The rate of seroconversion was higher in animals in the GIn experimental groups. In sheep, pre-existing moderate to high neutralizing titers against BVDV did not prevent viral replication and shed. The study demonstrated that naive cattle, goats and pigs, in addition to antibody positive sheep, can be infected by HoBi-like virus via persistently infected calf and potentially transmit the virus.

Exposure to bovine viral diarrhea viruses (BVDV) results in acute and persistent infections. Persistent infections result from in utero exposure during the first trimester of gestation. Clinical presentation, in persistently infected cattle (PI), is highly variable. The reasons for this variation is largely unknown. The BVDV circulating in PI exist as quasispecies (swarms of individual viruses). An outbreak resulting in 34 PI cattle presented an opportunity to compare a large number of PI׳s. Methods were developed to compare the circulating viral populations within PI animals. It was found that PI animals generated in the same outbreak carry circulating viral populations that differ widely in size and diversity. Further, it was demonstrated that variation in PI viral populations could be used as a quantifiable phenotype. This observation makes it possible to test the correlation of this phenotype to other phenotypes such as growth rate, congenital defects, viral shed and cytokine expression.

Pestivirus infections in ruminants result in significant economic losses worldwide. The aetiological agents are three species from the genus Pestivirus, family Flaviviridae, including bovine viral diarrhoea virus type 1 (BVDV-1), BVDV-2, border disease virus (BDV), and an atypical pestivirus named HoBi-like pestivirus. In this study, eighty-nine pestivirus isolates that were collected in Brazil between 1995 and 2014 and that originated from either cattle, fetal bovine serum (FBS) or as cell culture contaminants were genotyped based on a comparison of gene sequences from their 5' untranslated regions (5'UTR), N-terminal autoprotease (Npro ) and envelope glycoprotein 2 (E2). Of these isolates, 53.9% of the sequences were genotyped as BVDV-1, 33.7% as BVDV-2 and 12.4% as HoBi-like pestivirus. The prevalence of subgenotypes within the species was as follows: BVDV-1a (35.9%), BVDV-2b (31.4%), BVDV-1b (10.1%), BVDV-1d (6.7%), BVDV-2c (2.2%) and BVDV-1e (1.1%). BVDV-2c and BVDV-1e were detected for the first time in Brazil. This study revealed extensive genetic diversity among Brazilian pestivirus isolates, and the combination of pestiviruses that was detected is unique to Brazil. This information may serve as a foundation for designing and evaluating diagnostic tools and in the development of more effective vaccines; therefore, it may potentially contribute to pestivirus control and eradication.

Bovine viral diarrhea viruses (BVDV) are members of the Pestivirus genus within the family Flaviviridae. Based on antigenic and nucleotide differences, BVDV are classified into two recognized species, BVDV-1 and BVDV-2. More recently, a new putative pestivirus species, tentatively called "HoBi-like", has been associated with bovine viral diarrhea. HoBi-like viruses were first identified in fetal bovine serum (FBS) imported from Brazil. Subsequently, a number of HoBi-like viruses have been detected as contaminants in FBS or cell culture and in live ruminants. To further investigate the possible pestivirus contamination in commercially available FBS batches, 26 batches of FBS with various countries of origin, were tested in this study for the presence of bovine pestiviruses. All the 26 batches were positive by RT-PCR for at least one species of bovine pestiviruses. HoBi-like viruses were detected in 15 batches. Analysis of the 5'UTR and N(pro) sequences of 15 newly identified HoBi-like viruses combined with analysis of additional sequences from GenBank, identified 4 genetic groups tentatively named 3a-3d. The current study confirmed the presence of the emerging HoBi-like viruses in FBS products labeled with different geographic origins. This finding has obvious implications for the safety of biological products, such cell lines and vaccines.

Until the early 1990s there were just three recognized species in the pestivirus genus, bovine viral diarrhea virus (BVDV), border disease virus (BDV) and classical swine fever virus (CSFV). Subsequently BVDV were divided into two different species, BVDV1 and BVDV2 and four additional putative pestivirus species have been identified, based on phylogenetic analysis. The four putative pestivirus specices, listed in chronological order of published reports, are Giraffe (isolated from one of several giraffes in the Nanyuki District of Kenya suffering from mucosal disease-like symptoms), HoBi (first isolated from fetal bovine serum originating in Brazil and later from samples originating in Southeast Asia), Pronghorn (isolated from an emaciated blind pronghorn antelope in the USA), and Bungowannah (isolated following an outbreak in pigs, resulting in still birth and neonatal death, in Australia). In addition to the emergence of putative new species of pestivirus, changes in host and virulence of recognized or ‘classic’ pestiviruses have led to reevaluation of disease control programs and management of domestic and wildlife populations.

HoBi-like viruses, also referred to as bovine viral diarrhea virus 3 (BVDV-3) and atypical pestivirus, have been proposed as a new putative bovine pestivirus species. These viruses were first identified in the last decade and are currently distributed in at least three continents. Published findings suggest that these viruses may be endemic at least in parts of South America and Asia. The clinical presentations in cattle, described in field outbreaks and controlled studies, are similar to those associated with BVDV and range from subclinical to mild clinical signs, sporadically associated with reproductive losses, respiratory illness and hemorrhagic syndrome. The complete host range of HoBi-like virus is unknown, but data suggest higher adaptation of HoBi-like viruses to ruminants than swine. Acute infections, characterized by mild clinical signs, such as low-grade pyrexia and leukopenia, have been observed in both cattle and sheep. Virus has been isolated from nasal swabs indicating that virus was being shed. While seroconversion has been observed in pigs, no clinical presentation or viral shedding was evident following inoculation. While some commercial BVDV diagnostic tests may detect HoBi-like viruses, these tests do not differentiate between BVDV and HoBi-like viruses. The differentiation of BVDV and HoBi-like viruses is critical to the design of surveillance programs for these viruses.

Bovine viral diarrhea viruses (BVDV) can cause both acute and persistent infections in cattle. Exposure to BVDV persistently infected (PI) animals results in transmission of the virus to a naive animal which causes a transient acute infection. While it is known that direct exposure to PI animals is a highly efficient means of transmission, less information is available regarding the potential for transmission from acutely infected either by direct or indirect exposure to naive animals. Therefore, the objective of this study was to evaluate the potential for spread of the virus from calves acutely infected, with typical virulence field viruses know to have minimal shedding and viremia, to naive contact animals either by direct or indirect exposure. To accomplish this objective, two BVDV isolates belonging to two species of BVDV, type 1 and type 2, were used to inoculate calves. Subsequently on day 2 post-infection, naive calves were exposed to inoculated calves, either directly or indirectly, over a period of two weeks. All calves were evaluated for the presence of virus in blood samples and nasal swabs, pyrexia, lymphopenia and seroconversion. BVDV was isolated from inoculated calves but not from any of the direct and indirect contact animals or from control calves. Similarly, pyrexia and lymphopenia were observed in the inoculated calves, but not in contact and control calves. Only the inoculated calves seroconverted by day 38 of the study indicating that no transmission had occurred to the naive contact calves. This data would suggest that there may be an infectious dose needed for transmission of virus for typical virulent isolates.

Pestiviruses including Bovine viral diarrhea virus type 1 (BVDV-1), BVDV-2 and Border disease virus (BDV) have been reported in both sheep and cattle populations, together with the HoBi-like, an emerging group of pestiviruses. Pestivirus control programs in the United States have focused on the control of BVDV-1 and 2. The incidence of pestivirus infection in sheep in the United States and the risk of transmission between cattle and sheep populations are unknown. The aim of this study was to perform serological surveillance for pestivirus exposure in sheep from an important sheep producing state in the Unites States, Wyoming. For this, sera from 500 sheep, collected across the state of Wyoming (US) in 2015-2016, were examined by comparative virus neutralization assay against four species/proposed species of pestiviruses: BVDV-1, BVDV-2, BDV and HoBi-like virus. Rates of exposure varied between geographic regions within the state. The overall pestivirus prevalence of antibodies was 5.6%. Antibodies were most frequently detected against BVDV-1 (4%), and the highest antibody titers were also against BVDV-1. Data from this study highlights understanding of the dynamics of sheep pestivirus exposure, consideration of reference strains used for VN assays, transmission patterns, and potential vaccination history should be taken into account in implementation of control measures against pestiviruses in sheep and for successful BVDV control programs in cattle.

Bovine viral diarrhea virus (BVDV) is a positive single stranded RNA virus belonging to the Pestivirus genus of the Flaviviridae family. BVDV has a wide host range that includes most ruminants. Noncytopathic (ncp) BVDV may establish lifelong persistent infections in calves following infection of the fetus between 40 and 120 days of gestation. Cytopathic (cp) BVDV strains arise from ncp strains via mutations. The most common cp mutations are insertions of RNA derived from either host or a duplication of viral sequences into the region of the genome coding for the NS2/3 protein. Superinfection of a persistently infected animal with a cp virus can give rise to mucosal disease, a condition that is invariably fatal. A herd of 136 bred 3-year old cows was studied. These cows gave birth to 41 PI animals of which 23 succumbed to mucosal disease. In this study, we characterized the ncp and cp viruses isolated from 13 of these animals. All viruses belonged to the BVDV type 2a genotype and were highly similar. All the cp viruses contained an insertion in the NS2/3 coding region consisting of the sequences derived from the transcript encoding a DnaJ protein named Jiv90. Comparison of the inserted DnaJ regions along with the flanking viral sequences in the insertion 3' end of the 13 cp isolates revealed sequence identities ranging from 96% to 99% with common borders. This suggested that one animal likely developed a cp virus that then progressively spread to the other 12 animals. Interestingly, when the inserted mammalian gene replicated within viral genome, it showed conservation of the same conserved motifs between the different species, which may indicate a role for these motifs in the insertion function within the virus genome. This is the first characterization of multiple cp bovine viral diarrhea virus isolates that spread in a herd under natural conditions.

Bovine viral diarrhea virus (BVDV) has major impacts on beef cattle production worldwide, but the understanding of host animal genetic influence on illness is limited. This study evaluated rectal temperature, weight change and feed intake in Bos indicus crossbred steers (n = 366) that were challenged with BVDV Type 1b, and where family lines were stratified across three vaccine treatments of modified live (MLV), killed, (KV) or no vaccine (NON). Pyrexia classification based on 40.0 °C threshold following challenge and vaccine treatment were investigated for potential interactions with sire for weight change and feed intake following challenge. Pyrexia classification affected daily feed intake (ADFI, p = 0.05), and interacted with day (p < 0.001) for ADFI. Although low incidence of clinical signs was observed, there were marked reductions in average daily gain (ADG) and cumulative feed intake during the first 14 day post-challenge; ADG (CV of 104%) and feed efficiency were highly variable in the 14-day period immediately post-challenge as compared to the subsequent 14-day periods. A sire × vaccine strategy interaction affected ADFI (p < 0.001), and a sire by time period interaction affected ADG (p = 0.03) and total feed intake (p = 0.03). This study demonstrates that different coping responses may exist across genetic lines to the same pathogen, and that subclinical BVDV infection has a measurable impact on cattle production measures.

HoBi-like pestiviruses (also known as bovine viral diarrhea virus 3) have been sporadically reported from naturally infected cattle in Brazil, Asia, and Europe. Although HoBi-like viruses seem to be endemic in Brazilian cattle and buffalo, they have not been studied in the other countries of South America to our knowledge. Herein we report serologic results of buffalo from 12 large farms in Argentina located near the Brazilian border. These buffalo were not vaccinated against pestiviruses. Our results indicate that HoBi-like virus may be circulating in the northeastern region of Argentina given that half of the analyzed animals showed high levels of neutralizing antibodies against the pestivirus. The HoBi-like seropositive animals were also checked for neutralizing antibodies against BVDV-1a, BVDV-1b, and BVDV-2, and in most cases these animals had low levels or no detectable antibodies against these other pestiviruses. Our study suggests a need for continued pestivirus surveillance in Argentinean cattle and buffalo. Fil: Pecora, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Virología; Argentina Fil: Pérez Aguirreburualde, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Virología; Argentina Fil: Malacari, Darío A.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Virología; Argentina Fil: Zabal, Osvaldo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Virología; Argentina Fil: Sala, Juan Manuel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Corrientes. Estación Experimental Agropecuaria Mercedes; Argentina Fil: Konrad, José Luis. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina Fil: Caspe, Sergio Gastón. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Corrientes. Estación Experimental Agropecuaria Mercedes; Argentina Fil: Bauermann, Fernando. South Dakota State University; Estados Unidos Fil: Ridpath, Julia. United States Department of Agriculture; Estados Unidos Fil: Dus Santos, María José. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Bovine viral diarrhea virus (BVDV) 1b was isolated from tissues of a term bovine fetus with petechial hemorrhages noted throughout the body and placenta at autopsy. Fresh lung, kidney, thymus, and liver tissues were examined by direct fluorescent antibody testing and were positive for BVDV antigen and negative for bovine herpesvirus 1 antigen. An organ pool of fresh tissues was positive for noncytopathic (NCP) BVDV-1 by virus isolation. BVDV-1b was identified by sequencing of the 5’-UTR region of the genome. Fixed brain, placenta, thymus, lymph node, lung, kidney, skeletal muscle, liver, and bone marrow were positive for BVDV antigen by immunohistochemistry. Although BVDV hemorrhage and/or thrombocytopenia has been associated historically with NCP strains of BVDV-2, this case adds to more recent reports of BVDV-1 infections and hemorrhage in cattle. This BVDV-1b isolate should be investigated for its potential to cause hemorrhage in postnatal cattle.

The ruminant pestiviral species BVDV-1, BVDV-2 and BDV, along with the putative species HoBi-like, may cause substantial economic losses in cattle, sheep and goats. Brazil's large size, variable biomes and wide range of ruminant animal production within different geographic regions suggest that the presence and prevalence of ruminant pestivirus may differ by regions within Brazil. This study investigated the genetic diversity of ruminant pestiviruses and determined the frequency of active infections within two states of the Northeast Region of Brazil, Maranhao and Rio Grande do Norte. Serum samples from 16,621 cattle and 2,672 small ruminants from 569 different herds residing in this region were tested by RT-PCR followed by DNA sequencing. Seventeen positive cattle were detected (0.1%) from fifteen different herds (2.64%). All isolates were classified as HoBi-like pestiviruses based on phylogenetic analysis. All small ruminant samples tested negative. The findings presented herein suggest that the Northeast Region of Brazil has a uniquely high prevalence of HoBi-like viruses. The increasing reports of HoBi-like viruses detected in cattle in the field suggest that natural infection with these viruses may be more widespread than previously thought. The identification of HoBi-like viruses as the most prevalent type of ruminant pestivirus circulating in the Northeast Region of Brazil indicates the need for both continued monitoring and determination of the extent of economic losses associated with HoBi-like virus infections. In addition, it must be taken into account in the choice of diagnostic tests and in vaccine formulations.

A novel adenovirus, CeAdV1, was isolated from buffy coat and nasal swab samples collected from two captive white-tailed deer (Odocoileus virginianus) fawns. The isolation was an incidental finding in the course of screening animals for use in a research study on an unrelated pathogen. In the screening process, virus isolation was performed on both nasal swabs and buffy coat samples and cytopathic effect was observed. Electron microscopy revealed viral particles with the shape and morphology of an adenovirus. Next generation sequencing followed by phylogenetic analysis classified this virus to the Mastadenovirus genus. Its sequence was genetically distinct from all other recognized species in this genus, with only 76% sequence identity to its closest genetic match, bovine adenovirus 3 (BAdV3). The virus could be propagated in bovine derived cells but grew to a higher titer in cervid derived cells. Inoculation of white-tailed deer fawns with the isolated virus resulted in pyrexia, depletion of thymus tissue and mild respiratory disease. Comparative serology performed using convalescent sera revealed distinct antigenic differences between the novel cervid adenovirus and BAdV3. A retrospective serological survey of the captive deer herd indicated that this virus had been circulating in the herd for at least 14 years with no report of clinical disease. A survey of serum collected from free ranging mule deer residing in Nevada revealed high serum titers against this novel adenovirus.

Bovine viral diarrhea virus (BVDV) infects cattle populations worldwide, causing significant economic losses though its impact on animal health. Previous studies have reported the prevalence of BVDV species and subgenotypes in cattle from the United States and Canada. We investigated the genetic diversity of BVDV strains detected in bovine serum samples from 6 different Mexican regions. Sixty-two BVDV isolates from Mexico were genetically typed based on comparison of sequences from the 5′ untranslated region (5′-UTR) of the viral genome. Phylogenetic reconstruction indicated that 60 of the samples belonged to the BVDV-1 genotype and 2 to the BVDV-2 genotype. Comparison of partial 5′-UTR sequences clustered 49 samples within BVDV-1c, 8 samples within BVDV-1a, 3 samples within BVDV-1b, and 2 samples clustered with the BVDV-2a subgenotypes. Our study, combined with information previously published on BVDV field strain diversity in the United States and Canada, benefits the development of effective detection assays, vaccines, and control programs for North America.