Studies in the epidemiology and immunology of Babesia bovis, Babesia bigemina, and Anaplasma marginale in South Central Texas and Mexico

Abstract

Separate studies of the epidemiology and immunology of Babesia and Anaplasma in Texas and Mexico were examined. The studies entailed both field and laboratory investigations of the vectors involved in the transmission of the hemoparasites, treatment of infections with the parasites, development of immunoassays, and the preservation of infectious materials. Monthly herd prevalence rates for Anaplasma in a ranch Texas implicated Dermacentor albipictus as the primary vector of the rickettsia in that area. Treatment of acute infections of Babesia bigemina with oxytetracycline resulted in the the survival of three of the four infected animals. Antigen for the indirect fluorescent antibody test was preserved by lyophilization and found suitable for routine use for up to one year. The vermicule stage of the parasite was found to share antigenic specificity with the blood based stage. Cryopresvation of Babesia parasites was determined to be more efficient when prepared in a droplet manner than the conventional method. Adult male ticks were found to survive transfer from host to host, and were apparently infective for Babesia bigemina under experimentally controlled conditions.