Seroprevalence of the Strongyloides stercoralis Infection in Humans from Yungas Rainforest and Gran Chaco Region from Argentina and Bolivia

Abstract

The threadworm, <i>Strongyloides stercoralis</i>, is endemic in tropical and subtropical areas. Data on the prevalence and distribution of infection with this parasite species is scarce in many critical regions. We conducted a seroprevalence study of <i>S. stercoralis</i> infection in 13 locations in the Gran Chaco and Yungas regions of Argentina and Bolivia during the period 2010-2016. A total of 2803 human serum samples were analyzed by ELISA-NIE which has a sensitivity of 75% and specificity of 95%. Results showed that 551 (19.6%) of those samples were positive. The adjusted prevalence was 20.9%, (95% confidence interval (CI) 19.4%-22.4%). The distribution of cases was similar between females and males with an increase of prevalence with age. The prevalence in the different locations ranged from 7.75% in Pampa del Indio to 44.55% in Santa Victoria Este in the triple border between Argentina, Bolivia, and Paraguay in the Chaco region. Our results show that <i>S. stercoralis</i> is highly prevalent in the Chaco and Yungas regions, which should prompt prospective surveys to confirm our findings and the design and deployment of control measures.