Analysis of a growth-promoting factor for Babesia caballi cultivation

Serum-free media were examined to culture Babesia caballi. Daigo's T (DT) basal medium supplemented with Daigo's GF21 (GF21) or GIT medium, which already contains GF21, supported the parasite propagation at 37 C in a humidified atmosphere under 5% CO2 in air. Growth of B. caballi was dependent of the suitable concentration (10-20%) of GF21. Therefore, GF21 was suggested as the growth-promoting factor for B. caballi. However, GIT medium did not support the growth of parasites from cryopreserved stabilates, and serum supplementation was essential for the retrieval of parasites.