Growth of Babesia bovis parasites in stationary and suspension cultures and their use in experimental vaccination of cattle.

A combination of stationary culture and suspension culture was used to produce litre quantities of Babesia bovis parasites suitable for use as live vaccine. The Australian vaccine strain of B bovis, Ka, was maintained continuously in microaerophilus stationary phase (MASP) cultures, and for a short period in batch and flow-through spinner flask cultures. Although continuous culturing was not achieved in spinner flasks, the production of litre quantities of heavily parasitised erythrocytes was achieved more simply than by using MASP cultures. Ka strain parasites were maintained continuously in MASP culture for 174 days without altering their virulence or immunogenicity when compared to calf-derived parasites. Cultured parasites also survived storage at 4 degrees C for six days in basal medium, adding to their potential usefulness as a live vaccine in field situations.