Incidence of soil-transmitted helminthiasis (STH) infection in low income infants from Rio de Janeiro, Brazil

Annually, during three years, a prospective cohort study of soil-transmitted helminthiasis (STH) infection was done in 130 infants under 27 months old from a public day care centre that was under parasitological control program between 2001 and 2007. Preserved faecal samples were examined by formalin-ether sedimentation and Kato-Katz techniques. Mebendazole 200mg daily for three days was chose for the treatment of Ascaris lumbricoides and/or Trichuris trichiura infection, the only relevant helminthiasis were found. The follow-up during three years has shown that the prevalence of helminthological infection was 26,2%, 30,0%, and 36,9% of examined children, respectively. The incidence of intestinal helminthiasis was 20,8%. From the 34 infected ones at the first exam, about 56% of them were infected for A. lumbricoides and/or T. trichiura in the second year and 65% were infected in the third year. Ascaris lumbricoides and/or Trichuris trichiura were detected for two consecutive years in one third of them that were initially infected. We concluded that the annual helminthological control was not enough for reducing the prevalence of STH among young children. It is necessary to implement information, education and communication strategies to the parents in order to decrease the prevalence of these infections.