Epidemiology of toxocariasis in a steppe environment: the Patagonia study.

To investigate the epidemiology of human toxocariasis in a steppe environment, a field survey was carried out in three provinces of Argentina's Patagonia (Chubut, Neuquen, and Rio Negro) among 114 rural subjects residing in estancias (cattle- or sheep-breeding ranches). Overall seroprevalence was 31.6%, and the contamination rate of soil by Toxocara eggs was 35.1%. Bivariate and multivariate analyses were performed for various exposure variables and also for the De Martonne aridity-humidity index. Multivariate analysis revealed that the seroprevalence rate was found to be inversely correlated with age but was positively linked to De Martonne index. These findings suggest that the harsh climatic conditions existing in Argentina's Patagonia would inhibit embryonation of eggs in the soil, thus lowering the transmission of human toxocariasis.