Small type of Isospora bigemina: isolation from naturally infected cats and relations with toxoplasma oocyst
Ito, S.; Tsunoda, K.; Nishikawa, H.; Matsui, T.
National Institute of Animal Health Quarterly 14(3): 137-144
1974
ISSN/ISBN: 0027-951X PMID: 4437646 Document Number: 80065
From faecal samples of 446 cats examined, Isospora felis oocysts were detected in 39, those of I. rivolta in two and I. bigemina in seven. The oocysts of I.bigemina were either small (12.26X10.01 mu ) or big (15.94X13.07 mu ). The smaller oocysts were the same as of Toxoplasma oocysts (Beverley strain). Smaller oocysts on inoculation into mice produced toxoplasmosis in them but larger oocysts did not. The small oocysts were also morphologically and serologically similar to Toxoplasma oocysts. Cats fed brains of mice infected with small oocysts passed 106 to 107 oocysts/g of faeces. It was considered that the smaller oocysts were those of Toxoplasma.