title: Comparison of acute infection of calves exposed to a high-virulence or low-virulence bovine viral diarrhea virus or a HoBi-like virus.
abstract: OBJECTIVE
  To compare acute infection of cattle exposed to a high-virulence (HV) bovine viral diarrhea virus (BVDV), low-virulence (LV) BVDV, or HoBi-like virus.
  
  
  METHODS
  24 Holstein bull calves.
  
  
  METHODS
  Colostrum-deprived 2- to 4-week-old calves, free of BVDV antigen and antibodies, were allocated into 4 groups (6 calves/group). Calves in 3 groups were exposed to an LV BVDV strain (BVDV2-RS886), an HV BVDV strain (BVDV2-1373), or a HoBi-like virus (D32/00 HoBi), whereas calves in the fourth group were not exposed to a virus but were cohoused with calves exposed to the HoBi-like virus. Circulating WBCs, platelets, rectal temperature, and presence of virus in the blood were monitored.
  
  
  RESULTS
  Infection of calves with any of the 3 viruses resulted in reduced numbers of circulating WBCs. Pyrexia was detected in all calves exposed to HV BVDV or LV BVDV but in only 3 of 6 calves exposed to the HoBi-like virus. Diarrhea was observed in 0 of 6 calves exposed to the HoBi-like virus, 2 of 6 calves exposed to the LV BVDV, and 6 of 6 calves exposed to the HV BVDV. The HoBi-like virus was transmitted from acutely infected calves to naïve cohorts.
  
  
  CONCLUSIONS
  The HoBi-like viruses are an emerging species of pestivirus isolated from water buffalo and cattle in South America, Southeast Asia, and Europe but not from cattle in the United States. Understanding the clinical course of disease caused by HoBi-like pestiviruses will be important for the design of surveillance programs for the United States.
authors: Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, USDA, Agricultural Research Service, 1920 Dayton Ave, Ames, IA 50010, USA. julia.ridpath@ars.usda.gov
authors: Julia F
authors: JF
authors: Ridpath
authors: Shollie M
authors: SM
authors: Falkenberg
authors: Fernando V
authors: FV
authors: Bauermann
authors: Brian L
authors: BL
authors: VanderLey
authors: YoonJung
authors: Y
authors: Do
authors: Eduardo F
authors: EF
authors: Flores
authors: Dianne M
authors: DM
authors: Rodman
authors: John D
authors: JD
authors: Neill
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000097:blood / Q000276:immunology / Q000821:virology*; D002417:Cattle; D015331:Cohort Studies; D001908:Diarrhea Viruses, Bovine Viral / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D005334:Fever / Q000276:immunology / Q000662:veterinary / Q000821:virology; D018655:Lymphocyte Count / Q000662:veterinary; D008297:Male; D010976:Platelet Count / Q000662:veterinary; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D014774:Virulence
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral