Excretion of Toxoplasma gondii oocysts from Feral Cats in Korea

Abstract

Sporulated oocysts from the feces of infected cats with <i>Toxoplasma</i> <i>gondii</i> can cause detrimental disease in both humans and animals. To investigate the prevalence of feral cats that excrete <i>T</i>. <i>gondii</i> oocysts in the feces, we examined fecal samples of 563 feral cats over a 3-year period from 2009 to 2011. Oocysts of <i>T</i>. <i>gondii</i> excreted into the feces were found from 4 of 128 cats in 2009 (3.1%) and one of 228 (0.4%) in 2010 while none of the 207 cats in 2010 were found positive with oocysts in their feces, resulting in an overall prevalence rate of 0.89% (5/563) between 2009 and 2011. Among the 5 cats that tested positive with <i>T</i>. <i>gondii</i> oocysts, 4 of the cats were male and 1 was a female with an average body weight of 0.87 kg. Numerous tissue cysts of 60 µm in diameter with thin (<0.5 µm) cyst walls were found in the brain of one of the 5 cats on necropsy 2 months after the identification of oocysts in the feces. A PCR amplification of the <i>T</i>. <i>gondii</i>-like oocysts in the feces of the positive cats using the primer pairs Tox-5/Tox-8 and Hham34F/Hham3R confirmed the presence of <i>T</i>. <i>gondii</i> oocysts in the feces. This study provides a good indication of the risk assessment of feral cats in the transmission of <i>T</i>. <i>gondii</i> to humans in Korea.