Infection of the Mongolian gerbil with the cattle piroplasm Babesia divergens

Abstract

DISEASES of cattle caused by piroplasms are one of the major constraints on the growth of the livestock industry in the tropics. Babesia divergens, which is the common cause of redwater in European cattle, can be transmitted to splenectomised goats, sheep and deer by the inoculation of blood from infected cattle¹. Furthermore, it has been shown experimentally that B. divergens is transmissible in this way to chimpanzees². Evidence is now accumulating to suggest that it is this species of Babesia which is capable of causing fatalities in splenectomised humans in Europe^3,4. Our inability to adapt cattle piroplasms to small laboratory animals has restricted efforts to develop new drugs and vaccines against them. However, during a recent investigation of a human fatality⁵, we were able to transmit the parasite to gerbils by inoculation of infected blood from the patient. Although final evidence to implicate B. divergens in this instance is still being assessed, we decided to investigate the possibility of infecting gerbils with B. divergens-infected blood from cattle. We now report the successful adaptation of B. divergens to the Mongolian gerbil (Meriones unquiculatus).