Seroepidemiology of toxocariasis in a rural Tepehuanos population from Durango, Mexico

The epidemiology of toxocariasis in humans in Mexico has been poorly explored. There is a lack of information about toxocariasis in Tepehuanos, an indigenous ethnic group in Durango State in northern Mexico. Therefore, the presence of anti-Toxocara immunoglobulin (Ig) G antibodies was determined in 126 rural Tepehuanos using an enzyme-linked immunoassay. Socio-demographic, clinical and behavioural data of the participants were also obtained. Of the 126 Tepehuanos assessed (mean age 32.46 +/- 17.36 years), 33 (26.2%) had anti-Toxocara IgG antibodies. Multivariate analysis showed that Toxocara seropositivity was associated with unemployment (students and housewives) (odds ratio (OR)=3.1; 95% confidence interval (CI) 1.25-7.47). Other socio-demographic and behavioural characteristics, including age, educational level, contact with animals or soil, consumption of unwashed raw fruits and vegetables or untreated water, were not associated with Toxocara seropositivity. Clinical data were similar in seropositive and seronegative Tepehuanos. These results indicate that Toxocara exposure is common among Tepehuanos but Toxocara does not appear to impact on the health of the population. This is the first report of toxocaral infection in Tepehuanos, and of an association of toxocariasis in adults with unemployment. Further research is needed to elucidate the routes of transmission of Toxocara in Tepehuanos, including the role of hygiene practices, canine and feline contacts, paratenic hosts and soil contamination with infective Toxocara eggs.