Anaplasma marginale infections in dairy cattle:: Clinical disease with high seroprevalence

The fatal Anaplosma marginale infections were reported in a dairy cattle herd located in the Interior Aegean Region of Turkey fifteen Holstein dairy cows which had the symptoms of fever, weakness, depression, lack of appetite and decreasing of milk yields had died during January and March 2004. Inclusion bodies, characteristic of A. marginale, in erythrocytes of the sick cows were found. File presence of this agent was subsequently verified by serology. Then, the blood samples were collected from randomly selected 645 cattle which were grouped according to their age as follows: < 9 months, 9-12 months, and 1-2, 2-3, 3-4, > 4 years. The presence of A. marginale was determined by light microscopic examination of Giemsa-staincd blood smears. Serum samples were tested for the presence of antibodies against A. marginale by cELISA. Of 645 animals, 357 (55.35%) and 220 (34.11%)) were positive serologically and microscopically, respectively. The rates of the infection were different in the age groups. The specific antibodies against A. marginale were detected in 24.0%, 0.0%, 4.0%, 34.69%, 58.21%, and 82.07% of the cattle in the above age groups, respectively. The present report describes the first case of severe A marginale infection in a cattle herd.