CONTINUOUS IN-VITRO CULTIVATION OF BABESIA-OVATA

Basic method for in vitro cultivation of Babesia ovata was examined us ing a method which was developed by Vega et al. for cultivation of B. bigemina, a closely related organism. The parasites obtained from an i nfected SCID mouse were initiated their multiplication within adult bo vine RBC in Medium 199 supplemented with 40% adult bovine serum under a low oxygen atmosphere, 5% O2, 5% CO2 and 90% N-2. Although no prolif eration of B. ovata maintained in 5% CO2 in air was seen during the in itial 5 days, the parasites passaged three times under the low oxygen atmosphere were readily cultured in 5% CO2 in air, as well as under th e low oxygen atmosphere. The parasites were propagated in the RBC stor ed in Vega y Martinet solution at 4 degrees C for up to 2 months. Babe sia ovata-infected RBC from cultures were successfully cryopreserved i n 10% polyvinylpyrrolidone in Vega y Martinet solution and used to ini tiate new culture not only under the low oxygen atmosphere but also in 5% CO2 in air.