A progress report on the status of a new disease of American cats: cytauxzoonosis.

A protozoon disease of domestic cats in the U.S.A. which resembled diseases of African ungulates caused by blood parasites of the family Theileridae and the genus Cytauxzoon was first described by scientists of the University of Missouri in 1976. The Plum Island Animal Disease Center of the U.S. Department of Agriculture (USDA) became involved in an effort to discover the relationship of the parasite to those of African species and to ascertain if the disease posed a threat to American livestock. More than 500 cats were infected and the disease studied experimentally by scientists of both institutions. Passage of the parasite was accomplished by parenteral administration of fresh or deep frozen blood or tissues from infected cats. With the exception of a single cat, immunized at PIADC, the experimental disease has terminated fatally about 20 days following exposure. Most cats died within 9-15 days after infection. Diagnosis of the disease is accomplished by study of blood smears, stained with Giemsa and by examination of sections from major visceral organs. Piroplasms are not always found in blood smears, but large masses of schizonts are always found in at least one of the following organs: lungs, spleen, liver or lymph nodes. Since the disease almost invariably has a fatal termination in cats, it is believed that the reservoir is in another species of animal. The new disease has now been reported from Missouri, Arkansas, Texas and Georgia, with new isolations of the parasite having been made in recent months.