Risk factors for toxocaral ocular larva migrans: a case-control study.

Twenty-four patients with serologically confirmed toxocaral ocular larva migrans (OLM) and 24 age- and sex-matched controls were the subjects of an epidemiologic study. Information on the exposure to dogs and other factors possibly associated with transmission of toxocariasis was obtained by contacting the parents of the subjects. The odds of having had a dog present in the household within the year previous to onset of illness were 3 to 1 for cases vs controls. An association of pups (< 3 months) in the households of OLM patients within one year of onset was statistically significant (P < .05). Twenty-three of 24 OLM patients had had dogs in their homes some time before their illness, and the twenty-fourth patient had a history of geophagia, a behavioral pattern previously identified as a risk factor for toxocariasis. Exposure to cats and other animals in or outside the home did not differ for patients and controls. Infected dogs, especially pups, in the patients' homes were the most probably sources of infection for this group of OLM patients.