TRANSMISSION AND PERSISTENCE OF VTEC 0157:H7 ON CATTLE FARMS

摘要

The increasing number of human cases of a highly virulent type of VTEC 0157:H7 in Sweden is the result of domestic transmission originating in regional clusters of infected cattle farms. To control the spread of the bacteria, a comprehensive picture of infection dynamics, routes of transmission between farms and risk factors for persistence is urgently needed. This study combines information from farmer questionnaires, spatial data and molecular techniques to identify risk factors for the presence ofthe bacteria on farms. The results show that the most important risk factors are generally associated with biosecurity and indicate that an important transmission route may be visitors travelling between farms. They also suggest that VTEC 0157:H7 may persist in the farm environment for extended periods of time, and therefore specific on-farm measures to reduce environmental prevalence and spread between groups of animals may be required.