Continuous in vitro Cultivation of Babesia ovata

Abstract

Basic method for in vitro cultivation of Babesia ovata was examined using a method which was developed by Vega et al. for cultivation of B. bigemina, a closely related organism. The parasites obtained from an infected SCID mouse were initiated their multiplication within adult bovine RBC in Medium 199 supplemented with 40% adult bovine serum under a low oxygen atmosphere, 5% O₂, 5% CO₂ and 90% N₂. Although no proliferation of B. ovata maintained in 5% CO₂ in air was seen during the initial 5 days, the parasites passaged three times under the low oxygen atmosphere were readily cultured in 5% CO₂ in air, as well as under the low oxygen atmosphere. The parasites were propagated in the RBC stored in Vega y Martinez solution at 4℃ for up to 2 months. Babesia ovata-infected RBC from cultures were successfully cryopreserved in 10% polyvinylpyrrolidone in Vega y Martinez solution and used to initiate new culture not only under the low oxygen atmosphere but also in 5% CO₂ in air.