Prevalence and Characterization of Bovine Viral Diarrhea Virus in the White-Tailed Deer Population in Indiana

Bovine viral diarrhea in captive Rocky Mountain bighorn sheep associated with administration of a contaminated modified-live bluetongue virus vaccine

In late summer 2017, we observed acute, fatal cases of bovine viral diarrhea in captive Rocky Mountain bighorn sheep ( Ovis canadensis canadensis) in Colorado following use of a contaminated modified-live bluetongue virus vaccine. Following vaccination, at least 14 of 28 (50%) vaccinated bighorn sheep developed hemorrhagic diarrhea, and 6 of 28 (21%) vaccinated bighorn sheep died. Autopsy findings were predominantly necroulcerative-to-necrohemorrhagic gastrointestinal lesions. Less frequent lesions included suffusive hemorrhages of serosal surfaces of abdominal viscera, and lymphoid necrosis in gut-associated lymphoid tissues. All of the 6 bighorn sheep that died were positive on real-time PCR (rtPCR) for bovine viral diarrhea virus (BVDV) in multiple tissues. Seroconversion to BVDV-1 and immunohistochemistry for BVDV in affected tissues confirmed rtPCR results. Next-generation sequencing confirmed a match between the infecting strain of BVDV-1b and the contaminated vaccine.

Bovine Viral Diarrhea Virus (BVDV) in White-Tailed Deer (Odocoileus virginianus)

Bovine viral diarrhea virus (BVDV) is the prototypic member of the genus Pestivirus in the family Flaviviridae. Infections with BVDV cause substantial economic losses to the cattle industries, prompting various organized control programs in several countries. In North America, these control programs are focused on the identification and removal of persistently infected (PI) cattle, enhancement of BVDV-specific immunity through vaccination, and the implementation of biosecure farming practices. To be successful, control measures must be based on complete knowledge of the epidemiology of BVDV, including the recognition of other potential sources of the virus. BVDV does not possess strict host-specificity, and infections of over 50 species in the mammalian order Artiodactyla have been reported. Over 50 years ago, serologic surveys first suggested the susceptibility of white-tailed deer (Odocoileus virginianus), the most abundant free-ranging ruminant in North America, to BVDV. However, susceptibility of white-tailed deer to BVDV infection does not alone imply a role in the epidemiology of the virus. To be a potential wildlife reservoir, white-tailed deer must: (1) be susceptible to BVDV, (2) shed BVDV, (3) maintain BVDV in the population, and (4) have sufficient contact with cattle that allow spillback infections. Based on the current literature, this review discusses the potential of white-tailed deer to be a reservoir for BVDV.

Primary B-Cell Lymphoma of Submandibular Lymph Node in a Water Deer ( Hydropotes inermis )

We describe a B-cell lymphoma of a submandibular lymph node with metastasis to the lung and facial subcutaneous tissues in a water deer ( Hydropotes inermis ). Neoplastic cells contained pleomorphic lymphocytes that were positive for CD79a, consistent with B-cell lymphoma. PCR for bovine leukemia virus was negative.

Evidence of Bovine viral diarrhea virus Infection in Three Species of Sympatric Wild Ungulates in Nevada: Life History Strategies May Maintain Endemic Infections in Wild Populations

Evidence for bovine viral diarrhea virus (BVDV) infection was detected in 2009–2010 while investigating a pneumonia die-off in Rocky Mountain bighorn sheep (Ovis canadensis, canadensis), and sympatric mountain goats (Oreamnos americanum) in adjacent mountain ranges in Elko County, Nevada. Seroprevalence to BVDV-1 was 81% (N = 32) in the bighorns and 100% (N = 3) in the mountain goats. Serosurveillance from 2011 to 2015 of surviving bighorns and mountain goats as well as sympatric mule deer (Odocoileus hemionus), indicated a prevalence of 72% (N = 45), 45% (N = 51), and 51% (N = 342) respectively. All species had antibody titers to BVDV1 and BVDV2. BVDV1 was isolated in cell culture from three bighorn sheep and a mountain goat kid. BVDV2 was isolated from two mule deer. Six deer (N = 96) sampled in 2013 were positive for BVDV by antigen-capture ELISA on a single ear notch. Wild ungulates and cattle concurrently graze public and private lands in these two mountain ranges, thus providing potential for interspecies viral transmission. Like cattle, mule deer, mountain goats, and bighorn sheep can be infected with BVDV and can develop clinical disease including immunosuppression. Winter migration patterns that increase densities and species interaction during the first and second trimester of gestation may contribute to the long term maintenance of the virus in these wild ungulates. More studies are needed to determine the population level impacts of BVDV infection on these three species.

Spatial point pattern analyses of Bovine viral diarrhea virus infection in domestic livestock herds and concomitant seroprevalence in wild white-tailed deer (Odocoileus virginianus) in New York State, USA

Bovine viral diarrhea virus (BVDV) is an economically important disease of domestic cattle that is capable of infecting cervids. A first step in the formulation of a regional BVDV management plan is a local assessment of the likelihood of pathogen transmission from wildlife to domestic livestock. To achieve this, blood samples were collected from hunter-harvested white-tailed deer (Odocoileus virginianus) throughout New York State in the fall of 2009 and 2010. The SVANOVIR BVDV p80-AB enzyme-linked immunosorbent assay (ELISA; Svanova Biotech AV, Uppsala, Sweden) was used to screen sera for anti-BVDV antibodies. Because this ELISA is not validated for use in white-tailed deer, sera that tested positive were tested again using serum neutralization to verify the presence of antibodies. Spatial data describing the geographic location of BVDV antigen-positive cattle and camelid herds and BVDV-seropositive white-tailed deer were analyzed via the dual kernel density estimation method. In white-tailed deer, 7.48% (80/1,069) were BVDV-seropositive, whereas 3.43% (144/4,195) of tested herds were positive for BVDV antigen. An exploratory cluster analysis revealed 1 significant cluster of BVDV antigen-positive herds and 2 significant clusters of BVDV-seropositive deer. There was no spatial overlap between the clusters. The spatial point pattern and exploratory cluster analyses suggest that BVDV is maintained independently in domestic livestock herds in the western part of the state and in the white-tailed deer population in the northwestern part of the state.

Prevalence and spatial distribution of antibodies to bovine viral diarrhea virus and Coxiella burnetii in white-tailed deer (Odocoileus virginianus) in New York and Pennsylvania

Significant pathogens of domestic livestock and public-health related pathogens, such as bovine viral diarrhea virus (BVDV) and Coxiella burnetii, are commonly diagnosed in some wildlife species. BVDV is an economically important pathogen of domestic bovids and Coxiella burnetii is a highly infectious zoonotic bacterium. As a result of recent shifting patterns of disease, it is critical that baseline information regarding the status of both significant pathogens of domestic livestock and public-health related pathogens are established for commonly encountered wildlife such as white-tailed deer (Odocoileus virginianus). White-tailed deer are susceptible to both BVDV and C. burnetii infection, and the purpose of this study was to investigate for the presence of antibodies to these two pathogens in New York and Pennsylvania white-tailed deer. Exposure to BVDV and C. burnetii was determined using sera collected from 333 (219 males and 114 females) wild white-tailed deer in New York and 291 (130 males and 161 females) wild white-tailed deer from Pennsylvania. Samples were collected from hunter-harvested deer in central New York State in 2009 and live-captured deer in Pennsylvania in 2010. Sera were screened for anti-BVDV antibodies via a commercial blocking BVDV enzyme-linked immunosorbent assay. Coxiella burnetii phase II whole-cell antigen-coated slides were used to screen sera via an indirect microimmunofluorescence assay. Antibody prevalence was compared by sex class and location of collection. Deer in New York had higher antibody prevalence to BVDV (6.01%) than did deer in Pennsylvania (0.34%). Conversely, C. burnetii phase II antibodies were more common in Pennsylvania (20.96%) than in New York (14.41%). No statistically significant difference between locations was observed in either BVDV or C. burnetii antibody prevalence when data were analyzed by sex-class. Overall, C. burnetii seroprevalence was not significantly higher in Pennsylvania than in New York.

The occurrence of Bovine viral diarrhea virus in hunter-harvested white-tailed deer (Odocoileus virginianus) in the state of Georgia, southeastern United States

The prevalence of Bovine viral diarrhea virus (BVDV) in free-ranging white-tailed deer (WTD, Odocoileus virginianus) in the state of Georgia was evaluated using ear notches collected from hunter-harvested deer during the hunting season of 2010-2011. From September to December 2010, 367 ear samples from WTD were collected from 37 counties in Georgia. The samples were from 178 (48.5%) female deer, 187 (51%) male deer, and 2 (0.5%) of unknown sex. The age of the animals varied from 6 months to 6.5 years. The age was not recorded in 34 animals (9.3%). Of the animals with known ages, 42% were under 2 years. Screening of 367 samples for BVDV using an antigen-capture enzyme-linked immunosorbent assay (AgELISA) resulted in 364 negative samples and 3 suspect samples. The 3 suspect samples were negative for BVDV reverse transcription polymerase chain reaction (RT-PCR), virus isolation, and immunohistochemistry. A subpopulation of samples (n = 89) selected from various geographical regions also tested negative for BVDV RT-PCR. In conclusion, although a few of the samples were suspect for the presence of BVDV by AgELISA, the presence of the virus within the deer population studied could not be confirmed further.

Distribution of bovine viral diarrhoea virus antigen in persistently infected white-tailed deer (Odocoileus virginianus)

Infection with bovine viral diarrhoea virus (BVDV), analogous to that occurring in cattle, is reported rarely in white-tailed deer (Odocoileus virginianus). This study evaluated the distribution of BVDV antigen in persistently infected (PI) white-tailed deer and compared the findings with those from PI cattle. Six PI fawns (four live-born and two stillborn) from does exposed experimentally to either BVDV-1 or BVDV-2 were evaluated. Distribution and intensity of antigen expression in tissues was evaluated by immunohistochemistry. Data were analyzed in binary fashion with a proportional odds model. Viral antigen was distributed widely and was present in all 11 organ systems. Hepatobiliary, integumentary and reproductive systems were respectively 11.8, 15.4 and 21.6 times more likely to have higher antigen scores than the musculoskeletal system. Pronounced labelling occurred in epithelial tissues, which were 1.9-3.0 times likelier than other tissues to contain BVDV antigen. Antigen was present in >90% of samples of liver and skin, suggesting that skin biopsy samples are appropriate for BVDV diagnosis. Moderate to severe lymphoid depletion was detected and may hamper reliable detection of BVDV in lymphoid organs. Muscle tissue contained little antigen, except for in the cardiovascular system. Antigen was present infrequently in connective tissues. In nervous tissues, antigen expression frequency was 0.3-0.67. In the central nervous system (CNS), antigen was present in neurons and non-neuronal cells, including microglia, emphasizing that the CNS is a primary target for fetal BVDV infection. BVDV antigen distribution in PI white-tailed deer is similar to that in PI cattle.

Neurological diseases of ruminant livestock in Australia. IV: viral infections

Most viral infections that affect the central nervous system of ruminants are exotic to Australia. As such, this review focuses on viruses of importance in Australian ruminants, including Akabane virus and the ruminant pestiviruses, bovine viral diarrhoea virus and border disease virus, as well as bluetongue virus. Each virus is discussed in terms of pathogenesis, clinical signs and diagnosis.

Bovine viral diarrhea virus infections in heterologous species

Infections with Bovine viral diarrhea virus (BVDV) are not limited to cattle, but may be detected in various species in the mammalian order Artiodactyla. Despite epidemiological evidence of BVDV infections in species other than cattle, current knowledge regarding the impact of BVDV on heterologous species is incomplete. In heterologous hosts, BVDV infections with clinical signs analogous to those in cattle have been described and include disease of multiple organ systems, most notably the reproductive tract and immune system. Clinical infections may negatively impact the health and well-being of heterologous species, including camelids and captive and free-ranging wildlife. Of additional importance are BVDV infections in small ruminants and swine where difficulties arise in laboratory testing for Border disease virus (BDV) and Classical swine fever virus (CSFV), respectively. Pestiviruses are antigenically closely related and their cross-reactivity requires additional efforts in virological testing. In cattle populations, persistently infected animals are considered the main source of BVDV transmission. This phenomenon has also been detected in heterologous species, which could facilitate reservoirs for BVDV that may be of great importance where control programs are in progress. This review summarizes the current epidemiological and clinical knowledge on heterologous BVDV infections and discusses their implications.

Epidemiology and control of BVD in the U.S

The apparent prevalence of bovine viral diarrhea virus (BVDV) persistently infected cattle has been found to be low in U.S. dairies, beef herds and feedlots. Current management practices within U.S. cattle industries that impact the epidemiology of BVDV infections include purchasing untested cattle, lack of biosecurity procedures, large herd sizes, mixing cattle from multiple sources, high cattle densities in dairy and feedlot operations, synchronous breeding of beef herds, communal grazing and widespread vaccination. Evidence for BVDV infection has been found in farmed and free-ranging wildlife in North America; however the risk of BVDV transmission from wildlife to cattle is not known. The perception of a low prevalence of BVDV herd infections, the unrestricted sale of PI cattle, lack of economic data, intensive marketing of vaccines, reluctance to accept federal regulations, and a "gambler's" attitude among producers are impediments to implementation of a national systematic BVD control program. Since 2004, voluntary BVDV control programs have been organized in nine states reflecting the recognition of BVD as an important and preventable problem in the U.S.

Evidence for persistent Bovine viral diarrhea virus infection in a captive mountain goat (Oreamnos americanus)

Bovine viral diarrhea (BVD) viruses are pestiviruses that have been isolated from domestic and wild ruminants. There is serologic evidence of pestiviral infection in more than 40 species of free-range and captive mammals. Vertical transmission can produce persistently infected animals that are immunotolerant to the infecting strain of Bovine viral diarrhea virus (BVDV) and shed virus throughout their lives. Seven species (white-tailed deer, mouse deer, eland, domestic cattle, alpaca, sheep, and pigs) have been definitively identified as persistently infected with BVDV. This study provides serological, molecular, immunohistochemical, and histological evidence for BVDV infection in 2 captive mountain goats from a zoological park in Idaho. The study was triggered by isolation of BVDV from tissues and immunohistochemical identification of viral antigen within lesions of a 7-month-old male mountain goat (goat 1). Blood was collected from other mountain goats and white-tailed and mule deer on the premises for BVDV serum neutralization, viral isolation, and reverse transcription polymerase chain reaction. One 3-month-old mountain goat (goat 2) was antibody negative and BVDV positive in serum samples collected 3 months apart. This goat subsequently died, and though still antibody negative, BVDV was isolated from tissues and identified by immunohistochemistry within lesions. Sequencing and phylogenetic analysis identified the isolates as BVDV-2. These findings provide evidence of persistent infection in a mountain goat, underscoring the need for pestivirus control strategies for wild ruminants in zoological collections.