Investigation of an epizootic of bovine viral diarrhea virus infection in calves.
Eight of 19 calves born to bovine viral diarrhea virus (BVDV)-negative and -immunocompetent dams were determined to be infected with a noncytopathic strain of BVDV. Six of the 8 calves had diarrhea and 2 had no clinical signs of disease. In 3 euthanatized calves, lesions consistent with mucosal disease were found throughout the gastrointestinal tract, and the virus was isolated from the spleen, lymph nodes, and small intestine. In 5 calves, BVDV was isolated from mononuclear cells in blood samples obtained 21 days apart, indicating persistent infection. The virus was not isolated from sera obtained from 2 calves, with chronic nonclinical infections, that had neutralizing antibody titers > or = 1:512 against bovine viral diarrhea-Singer virus and titers > or = 1:256 against the persistent BVDV. Twenty-one days after vaccination with a vaccine that contained inactivated noncytopathic and cytopathic biotypes of BVDV, 4 of 5 persistently infected calves had neutralizing antibody titers < or = 1:4 against the bovine viral diarrhea-Singer virus and their persistent virus. Prior to vaccination, 2 of 11 virus-negative calves had neutralizing antibody titers < or = 1:128 against the bovine viral diarrhea-Singer virus, and after vaccination, only 1 virus-negative calf had a titer < or = 1:512. At 149 days after revaccination and prior to weaning, 4 virus-negative calves had neutralizing antibody titers < or = 1:512 (range, 1:16 to 1:384). Under the specific conditions in this herd, we were not able to detect a beneficial effect of vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Large Animal Clinical Sciences, Veterinary Medical Center, College of Veterinary Medicine, Michigan State University, East Lansing 48824.
R E
RE
Holland
D M
DM
Bezek
D J
DJ
Sprecher
J S
JS
Patterson
B A
BA
Steficek
A L
AL
Trapp
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000453:epidemiology*; D002417:Cattle; D003967:Diarrhea / Q000453:epidemiology / Q000662:veterinary; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology / Q000302:isolation & purification; D004064:Digestive System / Q000473:pathology; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000382:microbiology; D008297:Male; D014766:Viremia / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary
D000914:Antibodies, Viral; D007074:Immunoglobulin G