Epidemiological studies on toxocariasis and visceral larva migrans in a zone of western Spain.

An epidemiological study on toxocariasis was carried out in a zone of Western Spain (province of Salamanca) in dogs, soil and humans, comparing the simultaneous situations in urban and rural areas. The prevalence of infection in dogs was 29.4 to 33.1%, with little difference between the areas studied. The prevalence of Toxocara eggs in soil ranged from 3.7% in Salamanca city to 9% in rural areas. Seroprevalence in humans, as shown by Dot ELISA, was higher in children (8.5% in urban areas and 4.6% in rural areas) than in adults. The statistical significance of the correlations between prevalence and the different factors that affect transmission of the parasite was studied, and its importance at local level is discussed.