Recovery of bovine Babesia spp. after long-term cryostorage and comparison of bovine donor erythrocytes and serum.

Cultured Babesia bovis and Babesia bigemina were recovered from liquid nitrogen storage nearly 30 years after they were cryopreserved. Four cattle were compared as donors of erythrocytes and serum for microaerophilous stationary phase (MASP) cultures for recovery of B. bigemina. Erythrocytes and serum from only one (#913) of the four animals supported growth of B. bigemina. Two B. bigemina (frozen in 1986 and 1987) and two B. bovis (both frozen in 1986) cryostocks were recovered from liquid nitrogen storage and all four recovered and thrived in #913 erythrocytes and serum. In the third passage after recovery, B. bovis cultures were cryopreserved. Six months later they were successfully recovered using #913 erythrocytes and serum. This study shows that B. bovis and B. bigemina stored nearly 30 years in liquid nitrogen can be successfully recovered in the MASP system. This study also confirms previous observations that selection of a suitable bovine donor of erythrocytes and serum is critical to the success of the culture.