Submitted to: Veterinary Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/3/2013
Publication Date: 7/25/2013
Publication URL: http://handle.nal.usda.gov/10113/57376
Citation: Bauermann, F.V., Harmon, A., Flores, E.F., Falkenberg, S.M., Reecy, J.M., Ridpath, J.F. 2013. In vitro neutralization against HoBi-like viruses by antiobodies in serum of cattle immunized with inactivated or modified live vaccines of bovine viral diarrhea virus 1 and 2. Veterinary Microbiology. 166(1-2):242-245 DOI: 10.1016/j.vetmic.2013.04.032. Interpretive Summary: Bovine viral diarrhea viruses (BVDV) cause infections in cattle worldwide. In the United States vaccines are used to control BVDV infections in dairy and beef herds. Recently a new group of viruses, known as HoBi like viruses, have been isolated from cattle in Brazil, Italy and Thailand. HoBi like viruses are related to BVDV and cause very similar diseases in cattle. Introduction of HoBi like viruses into North America could result in significant economic loss by cattle producers. There are no vaccines available for the prevention of infection of cattle by HoBi like viruses. The purpose of this study was to determine if cattle vaccinated using BVDV vaccines might be protected against infection with HoBi like viruses. It was found that cattle vaccinated against BVDV would have little or no protection against infection with HoBi like viruses. This suggests that new vaccines, specific for HoBi like viruses, need to be developed to control this emerging pathogen.
Technical Abstract: HoBi-like viruses are an emerging species of pestiviruses with genetic and antigenic similarities to bovine viral diarrhea viruses 1 and 2 (BVDV1 and BVDV2). These viruses have been detected associated with respiratory and/or reproductive disease in cattle in Italy and Brazil. Vaccines for HoBi-like viruses are not yet available. However, both modified live virus (MLV) and killed virus (KV) vaccines against BVDV are widely used worldwide. This study evaluated the cross reactive antibody response against HoBi-like pestiviruses in sera of cattle immunized with BVDV1 and BVDV2 vaccines. Groups “KV” and “MLV”, with 25 calves each, received killed or MLV vaccines, respectively, containing both BVDV1 and BVDV2 antigens. The antibody response was evaluated by virus neutralization test. The average of geometric mean titers (GMT) of neutralizing antibodies in serum against HoBi-like viruses in the MLV group was 1.4, whereas GMTs to BVDV1 and BVDV2 were 5.1 and 2.7, respectively. In MLV group, neutralizing antibodies against BVDV1, BVDV2 and HoBi-like viruses were detected in 100%, 94% and 68% of calves, respectively. The GMT of neutralizing antibodies in serum against BVDV1 (GMT=3.1) in the KV group was higher than against BVDV2 (GMT=1.4) and HoBi-like virus (GMT=0.5). The percentage of animals with neutralizing antibodies against BVDV1, BVDV2 and HoBi-like viruses were 88%, 60%, and 34% respectively. These results indicate that BVDV1 and BVDV2 MLV or killed vaccines induce a comparatively weak antibody response cross reactive with HoBi-like viruses, and this response would likely not suffice to confer protection.