Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Review article
Publication Acceptance Date: 10/15/2012
Publication Date: 1/1/2013
Publication URL: http://handle.nal.usda.gov/10113/61199
Citation: Bauermann, F.V., Ridpath, J.F., Weiblen, R., Flores, F.F. 2013. HoBi-like viruses: an emerging group of pestiviruses. Journal of Veterinary Diagnostic Investigation. 25(1):6-15 DOI: 10.1177/1040638712473103. Interpretive Summary: Recently a new group of viruses has been found in cattle. The first virus characterized from this group was named HoBi virus and so when researchers began finding other viruses from this group they called them HoBi-like viruses. The appearance of the disease caused by this group of viruses is very similar to that caused by a group of viruses called bovine viral diarrhea viruses (BVDV) and include respiratory disease and fetal infections. One of the outcomes of fetal infection is the birth of calves that have life long viral infections. Infections with HoBi-like viruses have been confirmed in cattle in South American and Southeast Asia. It is feared that the introduction of HoBi-like viruses into other regions, such as the US, could have a negative impact on beef and dairy production. This article details what is known about HoBi-like viruses and the effectiveness of current diagnostic tests and vaccines in detecting and controlling these new viruses.
Technical Abstract: The genus Pestivirus is composed by four important pathogens of livestock: bovine viral diarrhea virus types 1 and 2 (BVDV-1 and BVDV-2), classical swine fever virus (CSFV) and border disease virus of sheep (BDV). BVDV are major pathogens of cattle and infection results in significant economic losses worldwide. A new putative pestivirus species, tentatively called HoBi-like, BVDV-3 or atypical pestiviruses, was first identified in Europe in fetal bovine serum (FBS) imported from Brazil. HoBi-like viruses are related to BVDV at the genetic and antigenic levels. Further, the disease caused by these new viruses resembles clinical presentations historically associated with BVDV infection, including growth retardation, reduced milk production, respiratory disease, reduced reproductive performance, and increased mortality among young stock. Current BVDV diagnostic tests may fail to detect HoBi-like viruses or to differentiate between BVDV and HoBi-like viruses. Further, commercial tests for BVDV exposure, based on serological response, do not reliable detect HoBi-like virus exposure and cross protection against HoBi-like viruses conferred by current BVDV vaccines is likely limited. As many HoBi-like viruses characterized to date were isolated from FBS originating from Brazil, it is assumed that the agent is probably widespread in Brazilian herds. Nevertheless, reports of natural infection in Southeast Asia and Europe demonstrate that these viruses are not restricted to South America. Increased demand for FBS has lead to widespread distribution of FBS originating in HoBi-like virus endemic regions. The contamination of such FBS with HoBi-like viruses may lead to spread of this virus to other regions.