Submitted to: United States Animal Health Association Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/17/2006
Publication Date: 10/12/2006
Citation: Ridpath, J.F. 2006. Bovine viral diarrhea: issues that need to be addressed as we work to improve BVDV control and move towards eradication [abstract]. United States Animal Health Association. p. 725. Interpretive Summary:
Technical Abstract: Acting alone or in conjunction with other pathogens, bovine viral diarrhea viruses (BVDV) are a source of major economic loss to the U.S. cattle producers. Losses are associated with outright mortality, reduced growth rates, reproductive failure and opportunistic infections by other pathogens in the presence of BVDV. These losses have prompted producer (National Cattleman’s Beef Association), regulatory (US Animal Health Association) and veterinary professional organizations (Academy of Veterinary Consultants, American Association of Bovine Practitioners) to put forward resolutions calling for the control and eventual eradication of BVDV from North America. In support of the control of BVDV, CRIS 065 (Innovative Detection Methods and Improved Control of Ruminant Viral Pathogens) within the Virus and Prion Diseases of Livestock Research Unit at the National Animal Disease Center, Ames, Iowa has led efforts to: 1. Determine the predominant genotypes and subgenotypes of BVDV circulating in the U.S. 2. Survey testing protocols, for BVDV detection, in use by AAVLD accredited diagnostic laboratories in U.S. 3. Determine if large scale pooling of ear notch samples is an effective approach to surveillance 4. Examine the impact of BVDV infections in species other than cattle. These studies have led to the following conclusions: 1. The subgenotype, BVDV1b, predominates in the U.S. (>60%), followed by BVDV2a (between 10% and 30%) with BVDV1a strains a distant third (<10%) 2. There is a wide range of expertise among accredited diagnostic laboratories with little agreement on the best diagnostic test, sample typing or testing strategy. 3. Pooling of 100 or more ear notch samples for use in PCR based tests is an unreliable practice based on concentration of BVDV in ear notches and results of blind test panels sent to independent laboratories. 4. Acute BVDV infections in white tail deer are very similar to acute BVDV infections in cattle. Infection of pregnant deer results reproductive problems similar to cattle including birth of persistently infected offspring. The existence of PI animals in a wildlife species that has common contact with cattle could have profound consequences for any BVDV control programs in cattle. Future research conducted at the NADC will include efforts to develop means to identify persistently infected (PI) animals in utero, design systematic surveillance programs for the identification of PI animals in beef and dairy operations and explore improved means of providing immune protection during the times of greatest vulnerability to BVDV infections.