Epidemiology of BHV 1 virus infections in dairy herds.
The epidemiology of bovine herpesvirus 1 (BHV 1) infections was studied in 20 dairy herds. Periodic serological surveillance of these herds during three consecutive years (1980-82) was combined with clinical studies. In 19 herds seropositive cows were found indicating previous exposure to BHV 1. One herd had its first experience with BHV 1 during the study. No indication of virus circulation for at least three years was found in eight herds. In five herds an interval of 2 years without an indication of virus circulation was followed by infections in yearlings, first- and second-calf cows during the third year. One or two cycles of virus circulation in calves and/or yearlings during the 3 year survey were detected in six herds. Most BHV 1 infections passed unnoticed. Signs of respiratory disease in association with BHV 1 infection were observed in three herds: young animals were most seriously affected. Clinical manifestations of BHV 1 infections were less pronounced than a few years ago when infections in cows caused frank signs and diagnosis was frequently possible on the basis of a typical clinical picture. BHV 1 was the cause of abortions in the herd that experienced its first infections during this survey. A survey of the age-specific BHV 1 neutralizing antibody pattern may be helpful for tracing animals and herds at risk of an outbreak of infectious bovine rhinotracheitis.
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D006564:Herpesviridae / Q000276:immunology; D006566:Herpesviridae Infections / Q000382:microbiology / Q000662:veterinary*; D007241:Infectious Bovine Rhinotracheitis / Q000517:prevention & control*; D009500:Neutralization Tests
D000914:Antibodies, Viral