Immunological characterization of human hosts to Ascaris lumbricoides and Trichuris trichiura infection in a population living in the rural municipality of Colomoncagua, Honduras (MPF6P.654)

Soil-transmitted helminth (STH) infections, specifically Ascaris, Trichuris, and Hookworm, compose three of the most prevalent Neglected Tropical Diseases, infecting over a billion people worldwide. Recurrent childhood STH infections have been shown to cause stunted physical growth, reduced physical fitness, and decreased school performance. Ascaris and Trichuris are of notable interest, given their abrupt decline from a peak prevalence and intensity in pre-adolescence to adulthood, with no known published works evaluating the possible underlying immunological mechanism. We used modern molecular techniques to (a) determine the burden of disease and (b) evaluate the immune profile of 30 adolescents and 51 adults between the ages 13-45, in rural Honduras, endemic for Ascaris and Trichuris. Using quantitative PCR of DNA extracted from stool we quantified the burden of disease of both Ascaris and Trichuris. Positive samples were stratified into groups based on the degree of infection, and controlled for with samples positive for 6 other common gastrointestinal parasites. Each group was immunologically characterized for serum Th1, Th2, and Th17 cytokines and associated antibodies. Results from this pilot study identify the basic serum immune profile associated with protection against Ascaris and Trichuris and serve as the foundation for a second, more comprehensive study that will guide vaccine antigen selection against each parasite by mimicking endemic host protective responses.