CRYOPRESERVATION OF BABESIA-CABALLI CULTURES

Babesia caballi cultures were cryopreserved with a solution of 10% (w/ v) polyvinylpyrrolidone 40 as cryoprotectant. Samples were cooled at r ates of 1, 10, 30 and 100 degrees C min(-1) using a programmable freez er. Additionally, a styrofoam box designed to cool samples at an appro ximate rate of 10 degrees C min(-1) when placed in a -80 degrees C fre ezer was used. Samples were stored in liquid nitrogen, thawed rapidly and inoculated into cultures. Although, a high loss of infectivity was observed after cryopreservation, cultures could be initiated reliably from cryo-stabilates frozen at a rate of 10 and 30 degrees C min(-1) or frozen with the styrofoam box.