Seroprevalence of antibodies to Strongyloides stercoralis NIE as a tool to identify communities for antihelmintic interventions in northern Argentina.

RUBÉN CIMINO; SILVANA CAJAL; MARISA JUAREZ; ADRIANA DI PAOLO; NORMA ACOSTA; CARLOS VILLALPANDO; EUGENIA SOCIAS; NOELIA FLORIDIA; JULIO NASSER; THOMAS NUTMAN; MONICA CARLOS; PATRICK LAMMIE; ALEJANDRO KROLEWIECKI

Filadelfia

Congreso; 60th Annual Meeting of the American Society of Tropical Medicine and Hygiene; 2011

American Society of Tropical Medicine and Hygiene

Infections with Strongyloides stercoralis (Ss) are cosmopolitan and mostly subclinical; new diagnostic approaches are needed to define the prevalence and distribution of infections and to monitor intervention activities. The identification of Ss-specific recombinant antigens increases the availability of serologic assays for these efforts. We evaluated the performance of Ss-NIE-1 by ELISA previously shown to be sensitive and specific in the setting of a mass deworming program in a rural community of northwestern Argentina (S 22°53´60´´; W64°20´06´´) with a total population of 618 people. Prior to drug administration for community-wide treatment, a subset of individuals was randomly selected for soil transmitted helminth (STH) assessment at baseline evaluation. Of the 80 persons (mean±SD age: 28.5± 20) who participated in the Ss study, 48 (mean±SD age: 30.5± 21) were also evaluated by stool analysis that included 4 techniques (concentration-sedimentation, agar plate, Harada-Mori and Baermann with bone charcoal culture). Serum samples were analyzed with the Ss-NIE-1 ELISA. The results demonstrated Ss larvae in 16% (8/48) stool samples; in contrast, 31% (25/80) were positive by serology (mean±SD age: 32.8.5± 20.8). Thus, there was a significant difference between the stool and more sensitive serum analysis (p<0.05 by Fisher’s exact test). Although three stool positive individuals (mean±SD age: 31.3± 22.4) were Ss-NIE seronegative, the known improved sensitivity of the SS-NIE ELISA for Ss infection with its higher throughput and ease of performance provides an epidemiologic tool to identify Ss-endemic regions of the world in need of anthelmintic therapy.  Moreover, the Ss-NIE ELISA confirmed the high prevalence of this STH in the study area, which aids in region-wide strategies for community intervention for this important STH.