A case-control study of the risk factors for cystic echinococcosis among the children of Río Negro province, Argentina

Abstract

In 1984 the prevalence of cystic echinococcosis (CE) in Rio Negro province in central Argentina reached alarming levels, with almost 6% of children aged 7-13 years infected with the causative agent, Echinococcus granulosus. Although the control activities developed between 1980-2000 have now lowered the prevalence of infection in this age-group to 1.1%, transmission of E. granulosus has clearly not ceased. The aim of the present study was to identify possible flaws in the control programme and the risk factors associated with CE. The 24 cases and 66 controls used were identified during a survey of the 1,070 schoolchildren attending 12 schools in Ingeniero Jacobacci, Rio Negro province. In interviews based around a standardized questionnaire, the adult female with responsibility for each subject (usually the mother but sometimes a grandmother or guardian) was asked 70 questions about the child and his or her immediate family, their contact with dogs and relevant environmentmental factors, and their level of contact with the control programme. Univariate and multivariate analyses were used to determine odds ratios (OR) and their 95% confidence intervals (CI). The main risk factors found to be significantly associated with CE were having a family member with the disease (OR = 3.11; CI = 0.92-10.47), spending the first years of life surrounded by a large number of dogs (OR = 2.11; CI = 1.2-3.5), and having a father who slaughtered sheep at his workplace (OR = 1.14; CI = 1.04-1.24). Obtaining drinking water from a tap (OR = 0.28; CI = 0.08-1.01) also remained in the final model, as a protective factor.