[Agricultural occupation and strongyloidiasis. A case-control study]

In the last few years, Strongyloides stercoralis has been repeatedly recovered from indigenous farmers in the Safor area (Valencia Community). The relationship between the different occupational activities, mainly farming, and the presence of strongyloidiasis was investigated.

A paired case-control study was designed. The investigation was conducted at Oliva Centro de Salud, from October 1997 to October 1999. Diagnosis was established when Strongyloides stercoralis was observed in any of the three serial fecal samples requested when eosinophilia was observed in the hemogram. Controls were persons matched by sex and age (+/- 5) years, with no eosinophilia in the hemogram and in whom the presence of the parasite was excluded in fecal samples.

Participants in the study were 47 cases and their respective controls. Each group included 39 (83%) men and 8 (17%) women. Forty-five cases (95%) and 42 controls (89%) had been born in Safor. Only two cases had travelled to endemic areas. Farming was the main activity in 32 (68%) cases and 31 (66%) controls. The only occupational activity which showed influence on strongyloidiasis was working in ricefields, with an OR of 2.97 (95% CI: 1.16-7.71). Dermatologic symptoms were significant for pruritus, OR 7.39 (95% CI: 2.29-27.60). One case with hyperinfection and another with larva currens were diagnosed.

In our area, working in ricefields and chronic pruritus are associated with chronic strongylodiasis.