Environmental health and the prevalence of parasites in children: A case-control study in Lima, Perú, South America

Lima, Peru, is a mega city of more than 10 million inhabitants. At least one-fourth of Lima’s population lives in shantytowns, locally known as “pueblos jóvenes,” many of which lack basic services such as running water, wastewater disposal, adequate housing, solid waste collection, and electricity. The primary objective of this presentation is to report the results of a research study conducted in the shantytown “El Trebol” and the Municipality of Pueblo Libre in Lima, Perú.

Forty (40) children ages four to eight years old and their families from El Trebol and 40 children ages four to eight years old and their families from Pueblo Libre participated in the study as experimental group and control group, respectively. A questionnaire was used to determine age, gender, family income, living conditions, access to health care, and education level among others. Each group received educational materials about the project and parents signed consent forms. Feces samples were collected from each child and analyzed for parasites by a licensed laboratory.

Results showed a great disparity between the experimental group and the control group. Ninety seven percent (97%) of the children from the experimental group tested positive for parasites as compared to 27% in the control group. The odd ratio for parasites among the experimental group as compared to the control group was 102, meaning that the children that live in the shantytown had a 100 times higher risk of being infected with parasites than the children that live in Pueblo Libre. The most common parasites found in the children were:

• Enterobius vermicularis,
• Giardia lamblia,
• Hymenolepis nana,
• and Ascaris lumbricoides.

Additional results and comparisons among both groups will be presented, as well as results from water samples collected in the shantytown. The study concluded that the lack of basic services in the shantytown increases the prevalence and risk for parasites in children.