Dogs as possible mechanical carriers of Toxoplasma, and their fur as a source of infection of young children

Only felines shed Toxoplasma gondii oocysts in their pet a dog and notice its smell later, if at all, before putting feces, and only they have been linked to fecal transtheir fingers in their mouth. The persistence of sporulated mission of the infecti0n.l After observing an association oocysts on the fur of dogs has not yet been studied, but between antibodies to Toxoplasma in Panamanian they persist in dry bedding for at least 4 days and in moist children and dog contact,2 we searched for how dogs bedding for 7 days.4 Unsporulated oocysts on the fur of might transmit the infection. dogs died when the relative humidity varied between Table 1 shows data from surveys in the USA, and 40% and 1OO%.5 Sporulation of Toxoplasma oocysts in indicates that dogs frequently eat the feces of cats, and cat feces takes place in 2-3 days.6 Additional studies that they roll in cat feces and other smelly substances. would be desirable, especially in the humid tropics. The latter habit has been called scent rolling,3 or, more In the interim, avoidance of dog contact should be broadly, xenosmophilia, liking foreign smells, and has added to the precautions to prevent Toxoplasma been demonstrated experimentally even with (Enjoli) infection. Ever since the cycle of Toxoplasma has been perfume. clarified,l toxoplasmosis has become a preventable Dogs could play a role in the fecal transmission of infection. Pregnant women, whose fetus is at risk, and Toxoplasma because they have the olfactory capacity immunocompromised patients, such as HIV-positive and the habit of seeking out and rolling in cat feces, individuals, should avoid Toxoplasma infection, which is contaminating their fur. Young children will often first asymptomatic in the normal population.