Much of the work funded by the Winn Foundation was concerned with increasing understanding of the disease in cats and in developing such a test. Dr. Lappin's work has shown that cats rarely become clinically ill with toxoplasmosis, usually only if they are themselves immunosupressed by disease or stress. Clinical cases do occur, however. Respiratory involvement is common in cats with both primary and secondary forms of the disease. Cats with respiratory toxoplasmosis often have a fever and show signs of malaise, weight loss and lack of appetite.
Labored breathing becomes more pronounced as the disease progresses.
Gastrointestinal signs are also common among cats with secondary toxoplasmosis. The most frequent signs are fever, weight loss, vomiting, diarrhea, mesenteric lymph node enlargement, and palpable thickening of the abdominal wall. Clinical signs resulting from central nervous system involvement include personality changes, incoordination, convulsions, unequal pupil size, blindness, plaintive crying, circling, ear twitching, and impaired swallowing. Ocular involvement can be the only sign of illness. Chronic and healed lesions can coexist in the same eye.