Effects of Corticosteroids in Stray Cats with Natural Antibodies to Toxoplasma gondii

Abstract

The effects of immunosuppression by corticosteroid treatment in stray cats having natural antibodies to Toxoplasma gondii were studied with regards to serum antibody level, oocyst shedding, mortality and pathology. Sera of 24 apparently healthy adult cats were screened for Toxoplasma infection by using the Latex agglutination test (LAT) and titre considered diagnostically significant (≥1:64) was detected in 33.33％ (8/24) cats with a maximum titre of 1:2,048. Six sero-positive cats with titre ≥1:512 were administered daily with oral or parenteral corticosteroids. Three out of 6 cats commenced shedding of Toxoplasma oocysts within 9 to 13 days and all cats died within 10 to 20 days post-corticosteroid treatment. The antibody titre declined 16 to 64 fold at the time of death. Gross and histopathological examination revealed visceral toxoplasmosis with necrosis in the liver, kidney and spleen and consolidation of the lungs. Toxoplasma gondii tachyzoites and cysts were demonstrated in the tissue sections of liver, lung, spleen and kidney of the cats.