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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #319009

Research Project: INTERVENTION STRATEGIES TO CONTROL VIRAL DISEASES OF CATTLE

Location: Ruminant Diseases and Immunology Research

Title: Experimental infection of calves, sheep, goats and pigs with HoBi-like viruses by direct inoculation or exposure to persistently infected calves

Author
item Bauermann, Fernando - Universidade Federal De Santa Maria
item Falkenberg, Shollie - Elanco Animal Health, Inc.
item Decaro, E - University Of Bari
item Ridpath, Julia

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2015
Publication Date: 12/31/2015
Publication URL: http://handle.nal.usda.gov/10113/61954
Citation: Bauermann, F.V., Falkenberg, S.M., Decari, E.F., Ridpath, J.F. 2015. Experimental infection of calves, sheep, goats and pigs with HoBi-like viruses by direct inoculation or exposure to persistently infected calves. Veterinary Microbiology. 181(3-4):289-293. doi: 10.1016/j.vetmic.2015.10.1011.

Interpretive Summary: The disease known as bovine viral diarrhea (BVD) leads to major loses in cattle production around the world. BVD may be caused by three different viruses, called bovine viral diarrhea virus 1 (BVDV1), BVDV2 and HoBi-like viruses. BVDV1 was discovered in the 1940’s. BVDV2 was discovered in the 1990’s. HoBi-like viruses were first reported in 2004. While BVDV1 and BVDV2 are detected in all parts of the world, HoBi-like viruses thus far have only been isolated from animals in South America, Asia and Europe. If a fetus is exposed to anyone of these three viruses, they may develop a lifelong persistent infection. Persistently infected animals are very efficient at spreading these viruses to other animals. Thus far HoBi-like viruses have only been reported in cattle and water buffalo. It is not known if HoBi-like viruses can be transmitted from calves with persist infection to pigs, goats or sheep. In order to design control programs that would keep HoBi-like viruses from spreading around that globe, it is important to determine if cattle persistently infected with HoBi-like viruses can transmit the virus to other domestic animals. In this study calves, sheep, goats and pigs were infected with HoBi-like viruses by direct inoculation (experimental route of infection) or by housing with calves persistently infected with HoBi-like viruses (natural route of infection). Cattle, sheep, goats and pigs all became infected, regardless of the route of infection, the risk that cattle infected with HoBi-like virus can transmit the virus will change that way we design control programs.

Technical Abstract: 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 counting, virus in buffy coats and nasal swabs up to day 23 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.