Overview: Babesiosis is a tick-borne protozoan disease caused by parasites of the genus Babesia that belong to the Piroplasmida. The disease is named after the Romanian bacteriologist Victor Babeş. Babesiosis is also known as piroplasmosis (from Latin pirum, meaning ‘pear’, and plasma, ‘image, formation’). Infection: Babesiosis affects domestic and wild animals and humans worldwide. While the disease is recognised in dogs around the world, it is found only rarely in cats. Human disease: Babesia species are common blood parasites of mammals. Human babesiosis is uncommon, but more cases in people have been reported recently, most likely because of rising awareness.