A large Babesia species was found in a leopard (Panthera pardus) in Kenya. It was established in domestic cats but no other animal was found to be susceptible. The parasite has been compared with other piroplasms of felids and it was found to differ from them in some significant characters. It was established as a new species and named Babesia pantherae.
We would like to thank Miss B. O. Vidler for her assistance, Dr S. F. Barnett for many helpful discussions and Professor N. D. Levine for pointing out the need for this description.
The parasite was isolated when we were working at the East African Veterinary Research Organization at Muguga in Kenya and we are most grateful to that organization for facilities.