236. Eosinophilia as a potential surrogate for the diagnosis of strongyloidiasis in an immigrant population and the utility of absent Ss-NIE antibodies as a biomarker for cure
Session: Poster Abstract Session: Diagnostic Microbiology
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Background: Determining the cause of persistent eosinophilia in immigrants to the United States can be hampered by costs needed to evaluate suspected parasitic infections. Thus, diagnosing eosinophilia-causing helminth infections by stool examination or serology is often beyond the means of community health clinics that commonly serve immigrant populations.

Methods: To define the causes of persistent eosinophilia among an immigrant population seen at a single community free health clinic, 54 patients (originally from Central and South America, Africa, Asia and the Middle East) who arrived in the United States 1-27 years (median 7 years) previously--were found to have an absolute eosinophil count (AEC)  >500/uL and were referred to the National Institutes of Health for further testing.

Results: Of the 54 referred patients, 43 (80%) had positive Strongyloides stercoralis (Ss)-specific serology.  1/43 (2%) also had schistosomiasis, 3/43 (7%) hookworm, and 2/43(5%) trichuriasis.  There were no differences in baseline eosinophil counts and serum IgE levels between those with Strongyloides and the 11/54 without (probably reflecting the referral criteria). All patients with a definitive parasitologic diagnosis received ivermectin and (when appropriate praziquantel and/or albendazole) treatment and followed over the course of a year. Not unexpectedly, there was a dramatic and significant (p<0.0002) decrease in AEC following treatment with all returning to normal levels by 1 year.  IgE levels also fell dramatically following treatment. Most importantly, antibodies to the Strongyloides-specific recombinant antigen (Ss-NIE) using a luciferase immunoprecipitation assay (LIPS) also became negative in all those with Ss treated successfully with ivermectin. 

Conclusion: Thus, in community clinics that provide health care to immigrants well after arrival in the United States, an AEC can be used as a surrogate for stool examination, and serology may be a trigger for empiric treatment when testing is limited by cost.  If available, newer serologic tests may replace insensitive stool examinations as tests of cure.

Rojelio Mejia, MD1, Kathryn Spates2, Nicole Holland2, Amara Pabon2, Jeananne Ware2 and Thomas Nutman, MD, FIDSA3, (1)National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, (2)National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, (3)Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD


R. Mejia, None

K. Spates, None

N. Holland, None

A. Pabon, None

J. Ware, None

T. Nutman, None

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