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.
Inoculation of canine kidney cell lines with cystozoites of Sarcocystishofmanni from a zoo-born Cervus albirostris, and of S. gracilis (syn. S. sibirica) from cattle resulted in the development of sporocysts. Inoculation of dog cell lines with cystozoites of S. cuniculorum did not succeed. Feline kidney cell lines were suitable for in vitro gamogony/sporogony of S. cuniculorum, but not of S. gracilis.
The microscopic examination of saline-diluted and iodine-stained wet mount preparations has satisfactorily been adopted in many laboratories as a simple and definite diagnostic measure. But, it is known that some difficulties have sometimes taken place in detection and identification of protozoa with this examination. We examined the usefulness of SAF (sodium acetate, acetic acid, and formalin) fixation, and alcian blue 8GS and pyronin B (AP) stain for wet mount preparations of fecal materials taken from amoebiasis and giardiasis patients in this study. SAF fixation was found very effective for preserving the morphological characters of protozoa, especially the inner structure, and for giving the good stainability to AP stain. The protozoa stained with AP, either trophozoites or cysts, showed the clear contour distinguishable from outer admixtures with the nuclear membrane and the karyosome stained deep purple, and the chromatoid body colored deep red. This was confirmed by the fact that the protozoa were not stained well with AP when not fixed with SAF. This method would be usable for the routine examination of fecal materials in intestinal protozoan infections, particularly Entamoeba histolytica and Giardia intestinalis infections. SAF fixative could also be used as a long-term preservative of protozoa in fecal materials.
This article reports the biochemical changes observed in 14 stray dogs experimentally infected with Trypanosoma evansi. The dogs were evaluated at days 0, 3, 6, 9 and 12 regarding the following parameters: glucose, urea, creatinine, uric acid, albumin, total proteins, alanineamine transferase (ALT), aspartatealanine transferase (AST) and creatinine phosphokinase (CK) employing non-enzymatic commercial kits. At the same time, 5 non-infected stray dogs were submitted to the same analysis. Only in the infected group changes were observed. Very slight increase with glucose and ALT levels were observed and only albumin decreased significantly in the whole analysed parameters. This suggested that edema may be the first clinical sign in chronic disease due to T. evansi.