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The objectives of this survey were to determine the testing methods for BVDV commonly in use by diagnostic laboratories, percentage of laboratories that provide follow up information following positive BVDV test results and the impact of testing strategy on detection., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2006

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 (MD), a condition that is invariably fatal., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2014

Bovine viral diarrhea viruses (BVDV) are found worldwide, and acute infections in cattle result in enteric, respiratory, and reproductive diseases of varying severity, depending on the BVDV strain, the immune and reproductive status of the host and the presence of secondary pathogens. While most commonly associated with cattle, there is evidence, based on serology and virus isolation, that BVDV replicates in a wide range of cervids. Because free-ranging cervid populations are frequently in contact with domestic cattle in the United States, possible transfer of BVDV between cattle and cervids has significant implication for proposed BVDV control programs. Previous research has demonstrated transmission of BVDV from persistently infected (Pl) deer to cattle and from PI cattle to deer via direct contact [1, 2]. While direct contact between wild cervids and cattle is observed in the field, indirect contact via cervid contamination of feed bunks, salt blocks and pasture is probably more common. Further, although PI animals are a major vector in the introduction of BVDV into naïve herds, circulation of the virus within a population is due, at least in part, to transmission of virus from acutely infected animals. In this study the transmission of BVDV to cattle from acutely infected deer via indirect contact is examined., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2009

Bovine viral diarrhea viruses (BVDV) infect a number of domestic and wildlife species besides cattle. Because free ranging cervid populations are frequently in contact with domestic cattle in the US, possible transfer of BVDV between cattle and cervids has significant implications for proposed BVDV control programs. BVDV has been isolated from German roe deer, Scottish deer, white tail deer and mousedeer, but little information is available regarding clinical presentation and progression of infection in these species. Preliminary studies of experimental infection of deer with BVDV have noted seroconversion but no clinical signs. In this study we infected white tail deer fawns, negative for BVDV and antibodies against BVDV, with either a type 1 or a type 2 BVDV The clinical progression following inoculation in these fawns was similar to that seen in BVDV infections in cattle and included fever and depletion of circulating lymphocytes., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2006

Infection with bovine viral diarrhea viruses (BVDV) is a major source of economic loss for the US cattle industry. Houe (2003) estimates that losses in areas where BVD is endemic range between $10 to 40 million per million calvings. Results of serology surveys in the US suggests that our losses are in the upper end of this range (Houe et al, 1995a; Houe et al, 1995b; Paisley et al, 1996). In 2004, 37.6 million calves were born in the US; thus, US losses by this estimate would be between $376 million to 1.5 billion for 2004. The 2005 calf crop was ~37.8 million, making the 2005 estimate very similar to that of 2004. While BVDV infections are well recognized as reproductive pathogens among dairy producers, producers are less aware that BVDV infections are also associated with increased respiratory disease, increased severity of secondary infections and decreased milk production. Persistently infected (PI) animals are the major vectors for spreading BVDV within and among herds. Based on studies of dairies of 100 cows or more, Joly et al (2005) estimated that the presence of one PI animal in a herd resulted in a loss of $1.93/cwt of milk sold. Studies estimate that 10-15% of US herds have at least one PI animal (Houe et al, 1995c; Wittum et al, 2001). In 2004, US dairies produced 170,805 million lb (77,638 kg) of milk. If 10% to 15% of dairy herds have at least one PI animal, then the cost to milk production is between $330 to 494 million per year. Control efforts in the US are geared towards identifying and eliminating Pis. Several tests based on detection of either antigen or viral RNA in blood, serum, bulk milk or skin biopsies are currently in use (Cornish et al, 2005; Fulton et al, 2006). Ear notch samples have become the tissue of choice for screening for PI animals because 1) they are easy to collect; 2) equipment requirements are minimal; 3) they are not affected by presence of passive antibodies; and 4) they can be used as the sample for a wide variety of tests including immunohistochemistry, real-time polymerase chain reaction and antigen-capture ELISA. While ear notches have become one of the samples of choice, there is little information available regarding sample size requirements and stability. Further, while pooling of ear notch samples has been proposed for reducing the cost of surveillance programs (Kennedy et al, 2006), the viral load available for detection from ear notch samples is largely undetermined. The purpose of this study was to establish working parameters for sample size, viral detection limit and sample storage conditions for real-time PCR and antigen-capture ELISA., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2006

Bovine viral diarrhea viruses (BVDV) represent significant pathogens for cattle. The BVDV affect several organ systems; however, the respiratory tract and fetal infections receive critical attention based on disease impact and potential for reservoirs/transmission. BVDV may cause primary infection of the respiratory tract and also serve to predispose the infected bovine to bacterial pathogens such as Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Archanobacterium pyogenes and Mycoplasma spp. Calves infected in utero and born persistently infected (PI) are important reservoirs of infection as they are life-long shedders of virus to susceptible cattle. Respiratory diseases in the feedlot are significant based on morbidity mortality and economic losses. Detection and removal of PI cattle could potentially lessen the economic effect of BVDV in the feedlot. Also, current BVDV control programs utilize vaccines in the US, primarily those containing BVDV1a and BVDV2a strains. Research at our institution has shown that the BVDV1b subgenotype is the major BVDV strain in our diagnostic laboratory accessions. The purpose of this study was three-fold: (1) determine prevalence of PI cattle entering a feedlot; (2) to utilize and compare various diagnostic tests to identify PI cattle; and (3) to determine the distribution of the BVDV1a, BVDV1b and BVDV2a subgenotypes in PI cattle entering the feedlot., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2005

The role of wildlife reservoirs continues to be a major unknown in the epidemiology of bovine viral diarrhea virus (BVDV). Serological data indicates that a wide range of wild ruminants have BVDV antibodies. BVDV has been isolated from a mule deer in Wyoming. In this report we examine the gross, histological and virological findings of two isolations of BVDV in whitetail deer in southeastern South Dakota in areas with concentrations of feedlot, dairy and cow-calf operations., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2004

Bovine viral diarrhea virus (BVDV) infections, in both persistently infected (PI) and/or acutely infected calves, were investigated in commingled and transported calves. Other viral infections such as bovine herpesvirus-1 (BHV), parainfluenza-3 virus (Pl-3V), bovine respiratory syncytial virus (BRSV), and bovine adenoviruses (BAV) were monitored, as well as interactions with Mannheimia haemolytica and Pasteurella multocida., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2001