Study on the seroprevalence of infections by Mycoplasma bovis in Swiss cattle including epidemiological analysis of risk factors in a local population (Jura region)

Sporadic cases of infection with Mycoplasma bovis have been observed in Swi tzerland since 1983. However, five severe outbreaks of endemic mastitis in a geographically distinct, small region (Canton du Jura) during the period 1995 to 1997 prompted the present investigation on the seroprevalence of in fection with M. bovis among milking cows in Switzerland. A commercially prepared indirect enzyme immunoassay was used. Among a strat ified random sample of 118 herds of milking cows in Switzerland, at least o ne positive animal was detected in 56 (47%) of the herds, whereas 6,1% of t he 1816 individual animals tested positive. An epidemiological study was performed in the Canton du Jura region among 5 1 herds in order to assess the importance of management factors in the spre ad of M. bovis infection. The herd-level prevalence was 78%, and the seropr evalence at the level of the 1354 individual animals tested was 13,4%. A mu ltivariate analysis of possible risk factors showed purchase of animals to be the only variable significantly associated with serological status of th e herd with an "odds ratio" of 10,8.