Synonyms: Babesiella felis, Nuttallia felis var. domestica.
Hosts: Domestic cat, wild cat (Felis lybica), puma (F. concolor), lion (F. leo), American lynx (Lynx rufus), Indian leopard (Panthera pardus).
Geographic Distribution: Africa, India, North America (California) (?). This species was first found in a wild cat in the Sudan and has since been found in domestic cats in India and South Africa, in the lion in the French Sudan and in the Indian leopard. In addition, it was found in 2 pumas imported into Egypt from California and in an American lynx in the London zoo. It has not been found in animals still in North America, so its existence on this continent is still problematical.
Morphology: This is a small form. Most of the trophozoites are round or irregularly round and 1.5 to 2 u in diameter. Some are elongate and 2 to 3, or rarely 4 u long. Piriform trophozoites are rare. Division is quadruple, forming a cruciform schizont, or binary.
Life Cycle: The vectors are unknown, altho Haemaphysalis leachi has been incriminated in South Africa.
Pathogenesis: Feline babesiosis is less severe than the canine disease, and affected animals usually recover without treatment. It is characterized by anemia, slow respiration, somnolence, listlessness, emaciation, constipation with yellow or orange feces, splenomegaly, and sometimes icterus and hemoglobinuria.
Treatment: Both trypan blue and acaprin are effective against B. felis.