Results of a combined public health intervention against S. stercoralis in an Argentinean endemic region monitored through NIE ELISA.

ECHAZÚ A; CARO RN; CIMINO RO; VARGAS P; JUAREZ M; CAJAL SP; NASSER J; KROLEWIECKI A

Atlanta

Congreso; 65th Annual Meeting of the American Society of Tropical Medicine and Hygiene; 2016

American Society of Tropical Medicine and Hygiene

Northwestern Argentina is a hyperendemic area for soil transmitted helminth infection, where annual deworming programs are carried out in prioritized areas for its control. In the particular case of Strongyloides stercoralis, high prevalence was reported in this area (30-50%); therefore, ivermectin has been included in the chemotherapy. In this context, assessing the S. stercoralis response to therapy in the treated population has become a major concern. The NIE ELISA was used for this purpose since it proved to be more sensitive than conventional parasitological techniques for the diagnosis of S. stercoralis. This community trial was conducted in two groups of patients, classified according to differences in housing and living conditions. After the first sampling and deworming (Massive Drug Administration, MDA), Group 1 (G1) was moved to new households with drinking water access and improved sanitation facilities (MDA+WAS intervention); while Group 2 (G2) remained living in less developed conditions with unimproved drinking water and sanitation (MDA intervention). The mean interval times between baseline (Base) and the follow up (F/U) were 359 days for G1 and 478 for G2. Anti-NIE antibody titers (Optical Density, OD) were measured for each individual before and after interventions (paired sera). A follow up OD ratio (ODF/U/ODBase) was calculated to quantify the variation in antibody titers. A significant decrease of the anti-NIE titers (p