Prevalence of Human Cystic Echinococcosis in Rio Negro Province, Argentina and Direct Risk Factors for Infection

Abstract Background: Cystic echinococcosis (CE) is a parasitic zoonosis caused by infection with the larval stage of Echinococcus granulosus sensu lato This study investigated the prevalence and potential risk factors associated with human CE in the towns and rural areas of Ñorquinco and Ramos Mexia, Rio Negro province, Argentina. Methods: In order to detect abdominal CE cysts, we screened 892 volunteers by ultrasound and investigated potential risk factors for CE using a standardized questionnaire. Bivariate and multivariate analyses were used to estimate the Prevalence Ratio (PR) and their 95% CIs of the association between CE and the factors investigated. Results: Abdominal CE was detected in 42/892 screened volunteers (4.7%, CI 3.2-6.1), only two of who being under 15 years of age. Thirteen CE (30.9%) cases had 25 cysts in active stages (CE1, CE2, CE3) The most relevant risk factors identified in the bivariate analysis included: live in rural area (p=0.003), age >40 years (p=0.000), drinking always water of natural source (p=0.007), residing in rural areas during first five years of life (p=0.000) and live more than 20 years at your current address (p=0.013). In the multivariate model, statistically significant risk factors were: frequently touch dogs (p=0.012), residing in rural areas during first five years of life (p=0.004), smoking (p=0.000), age > 60 years (p­­=0.002) and live in rural areas (p=0.017).Conclusions: our results point toward infection with CE being acquired since childhood and with constant exposure throughout life, especially in rural areas with a general environmental contamination