SEROLOGICAL TESTING ON THE OCCURRENCE OF BOVINE EHRLICHIOSIS IN THE CANTONS ZURICH, SCHAFFHAUSEN, THURGAU, ST.-GALLEN AND OBWALDEN

The purpose of this study-was to investigate the geographical distribu tion of bovine ehrlichiosis in the Cantons Zurich, Schaffhausen, Thurg au, St. Gallen and Obwalden. To this end, an indirect immunofluorescen ce assay was established. The diagnostic sensitivity and specificity w as estimated to be close to 100%-based on the results obtained with se veral reference sera from the US National Veterinary Services Laborato ries and the seroconversion panels of 20 heifers and cows. Blood sampl es from 2557 healthy cattle were tested for antibody response against Ehrlichia phagocytophila. Ninety-three animals (3.6%) were seropositiv e with titers ranging from 1.20 to 1:320. Most of the positive animals were found in the area north of lake Zurich spanning to the german bo rder,:in the area between Walensee and Bad Ragaz,the Rhine valley and Klein Melchtal. All seropositive animals had grazed on pastures or alp s with a favourable bio-top for the tick Ixodes ricinus.