Tick-borne diseases of cattle in Paraguay. I. Seroepidemiological studies on anaplasmosis and babesiosis.

A serological survey was carried out in Paraguay to determine the prevalence of antibodies to Anaplasma marginale, Babesia bigemina and Babesia bovis. The results suggest that the parasites are widely distributed throughout the country with prevalence rates of 92% for A. marginale, 79% for B. bigemina and 71% for B. bovis. Epidemiological studies on calves demonstrated that initial infection with the three blood parasites occurs in most animals within the first nine months of life. It is likely therefore that most of the country can be considered as being enzootically stable with respect to anaplasmosis and babesiosis.