Prevalence of human cystic echinococcosis in the towns of Ñorquinco and Ramos Mexia in Rio Negro Province, Argentina, and direct risk factors for infection

Fil: Uchiumi, Leonardo. Ministerio de Salud de Rio Negro, Hospital Zatti,, Rio NegroFil: Mugica, Guillermo. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NegroFil: Araya, Daniel. Ministerio de Salud de Rio Negro, Ssluf Ambiental, Rio NegroFil: Salvitti, Juan. Ministerio de Salud de Rio Negro, Hospital Bariloche, Rio NegroFil: Sobrino, Mariano. Ministerio de Salud de Rio Negro, Hospital Bariloiche, Rio NegroFil: Moguilansky, Sergio. Universidad Nacional del Comahue, Catedra de Imagenes, Rio NegroFil: Solari, Santiago. Ministerio de Salud de Rio Negro, Hospital Valcheta, Rio NegroFil: Blanco, Patricia. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NedgroFil: Lamounier, Janette. Ministerio de Salud de Rio Negro, Hospital Ñorquinco, Rio NegroFil: Barrera, Federica. Ministerio de Salud de Rio Negro, Hospital Ramos Mexia, Rio NegroFil: Arezo, Marcos. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NegroFil: Seleiman, Marcos. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NegroFil: Yadon, Zaida. Academia Nacional de Medicina, Instituto investigaciones Epidemiologicas. Buenos AiresFil: Tamarozzi, Feamcesca. Universidad de La Sapienzia, Roma, ItaliaFil: Casulli, Adriano. Universidad de Las Sapienza, FRoma, ItaliaFil: Larrieu, Edmundo. Universidad Nacional de Rio Negro, Escuela de Veterinaria. Rio Negro. Argentina.Background: Cystic echinococcosis (CE) is a parasitic zoonosis caused by infection with the larval stage of Echinococcus granulosus (s.l.). 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: To detect abdominal CE cysts, we screened 892 volunteers by ultrasound and investigated potential risk factors for CE using a standardized questionnaire. Prevalence ratio (PR) with 95% confidence intervals (CI) was used to measure the association between CE and the factors investigated, applying bivariate and multivariate analyses. Results: Abdominal CE was detected in 42/892 screened volunteers (4.7%, 95% CI 3.2–6.1), only two of whom were under 15 years of age. Thirteen (30.9%) CE cases had 25 cysts in active stages (CE1, CE2, CE3a, according to the WHO Informal Working Group on Echinococcosis [WHO-IWGE] classification). The most relevant risk factors identified in the bivariate analysis included: living in rural areas (P = 0.003), age > 40 years (P = 0.000), always drinking water from natural sources (P = 0.007), residing in rural areas during the first 5 years of life (P = 0.000) and having lived more than 20 years at the current address (P = 0.013). In the multivariate final model, the statistically significant risk factors were: frequently touching dogs (P = 0.012), residing in rural areas during the first 5 years of life (P = 0.004), smoking (P = 0.000), age > 60 years (P = 0.002) and living 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. Keywords: Cystic echinococcosis, Echinococcus granulosus (s.l.), Ultrasound screening, Epidemiology, Risk factors