HISTOLOGICALLY CONFIRMED CLINICAL TOXOPLASMOSIS IN CATS - 100 CASES (1952-1990)

Tissue sections from 119 cats that died or were euthanatized (1952-199 0) because of toxoplasmosis-like illness were reexamined for Toxoplasm a gondii by direct microscopy and immunohistochemical staining with an ti-T gondii serum. Clinical and pathologic data from 100 of these cats with histologically verified toxoplasmosis were then analyzed. Of the se 100 cats, 36 were considered to have generalized toxoplasmosis, 26 predominantly pulmonary lesions, 16 abdominal, 1 hepatic, 1 parcreatic , 1 cardiac, 2 cutaneous, 7 neurologic, and 9 had neonatal toxoplasmos is. In 14 cats, concurrent microbial infections or other maladies were seen. Cats were 2 weeks to 16 years old (median, 2 years; mean, 4 yea rs). Sixty-five cats were males and 34 were females; sex was not recor ded for 1 cat. Of 67 cats that had rectal temperatures recorded, 49 (7 3%) had fever (40.0 to 41.7 C). Dyspnea, polypnea, and signs of abdomi nal discomfort were frequently observed. Toxoplasmosis had been confir med antemortem in 8 cats; 4 had a serum antibody titer to T gondii of greater-than-or-equal 1:1,024; and T gondii had been found in cytologi c evaluation of tracheal aspirates from 2 cats and pleural fluid from 1 cat, as well as in a biopsy specimen of a mesenteric lymph node from another. Of the 15 cats with T gondii serum-antibody titers determine d by the Sabin-Feldman dye test, 6 had no antibody detected in 1:4 dil ution of their serum. Indirect fluorescent antibody titers were found in 10 of 10 cats' sera tested. Forty-one eyes from 27 of the cats were examined microscopically. Twenty-two of the 27 cats (81.5%) had evide nce of intraocular inflammation in one or both eyes. Multifocal iridoc yclochoroiditis was the most common lesion and was seen in 18 (81.8%) of the cats with ophthalmitis. The ciliary body was the most often sev erely affected portion of the uvea. Of the 22 cats with ocular toxopla smosis, T gondii was found in eyes of 10. Toxoplasma gondii was found in the retina of 5 cats, the choroid of 2, the optic nerve of 1, the i ris of 3, and the ciliary body of 4. Toxoplasma gondii was identified in 80% of 55 brains, 70.0% of 90 livers, 76.7% of 86 lungs, 64.4% of 4 5 pancreata, 62.7% of 59 hearts, 45.8% of 72 spleens, 41.5% of 65 inte stines, 17.7% of 61 kidneys, and 60.0% of 30 adrenal glands.