Abstract

Longitudinal pinworm (Enterobius vermicularis) infection rates were estimated at a mass screening for first-grade children during 1991-1996; children were provided medication at the screening. This campaign was able to decrease the infection rates for the 1991 cohort from 16.3% to 0.6%. A case-control study was further conducted for the investigation of risk factors among fourth-graders. Cases comprised 429 children with at least one infection between September 1996 to June 1999, and controls were 280 randomly selected uninfected classmates. Parents were asked to complete a questionnaire survey to report students' personnel hygiene habits. The case-control study revealed that significant factors associated with the infection included playing on the floor (odds ratio [OR], 2.5), nail biting (OR, 2.1), failure to wash hands before meals (OR, 1.7) and living in nonapartment dwellings (OR, 1.6). Girls were at a higher, but not significant, risk (OR, 1.4), than boys. In conclusion, inadequate personal hygiene increases the risk for pinworm infection. The mass screening-medication campaign can be adapted to countries with a similar parasitic problem.