IN-VITRO CULTIVATION OF A BABESIA SP FROM CATTLE IN SOUTH-AFRICA

A South African Babesia sp. of cattle which is as yet unclassified, wa s continuously cultivated in micro-aerophilous stationary-phase cultur e. The parasites were resuscitated from a blood stabilate stored in li quid nitrogen. A modified HL-1. medium supplemented with either horse or bovine serum was used. Cultures were initiated in a humidified atmo sphere containing 2% O-2, 5% CO2 and 93% N-2 at 37 degrees C. Parasite s were detected on Giemsa-stained smears after 2 d in culture. On day 4, the cultures were split at a ratio of 1:2 (v/v) and transferred int o a humidified atmosphere of 5% CO2 in air. Starting from day 6, subcu ltures were made daily at a ratio of 1:4 (v/v). The percentage of para sitized erythrocytes ranged from 2-5%. Addition of purine bases (hypox anthine, adenine, adenosine or guanosine) was essential for the contin uous propagation of the parasites when bovine, but not horse serum, wa s used for medium supplementation.