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  • Field survey for strongyloidiasis in eastern Uganda with observations on efficacy of preventive chemotherapy and co-occurrence of soil-transmitted helminthiasis/intestinal schistosomiasis

Journal of Helminthology

Table of Contents - September 2011 - Volume 85, Issue 03  

Research Papers

Field survey for strongyloidiasis in eastern Uganda with observations on efficacy of preventive chemotherapy and co-occurrence of soil-transmitted helminthiasis/intestinal schistosomiasis

J.C. Sousa-Figueiredoa1a2, M. Daya3, M. Betsona1, C. Rowella4, A. Wambokoa4, M. Arinaitwea4, F. Kazibwea4, N.B. Kabatereinea4 and J.R. Stotharda1 c1

a1 WHO Collaborating Centre Schistosomiasis, Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, London SW7 5BD, United Kingdom

a2 Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom

a3 Faculty of Medicine, University of Dundee, Nethergate, Dundee DD1 4HH, United Kingdom

a4 Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda

Abstract

Following our previous field surveys for strongyloidiasis in western Uganda, 120 mothers and 232 children from four villages in eastern Uganda were examined, with two subsequent investigative follow-ups. As before, a variety of diagnostic methods were used: Baermann concentration, Koga agar plate and strongyloidid enzyme-linked immunosorbent assay (ELISA), as well as Kato–Katz faecal smears for detection of eggs of other helminths. At baseline, the general prevalence of Strongyloides stercoralis was moderate: 5.4% as estimated by Baermann and Koga agar methods combined. A much higher estimate was found by ELISA (42.3%) which, in this eastern setting, appeared to be confounded by putative cross-reaction(s) with other nematode infections. Preventive chemotherapy using praziquantel and albendazole was offered to all participants at baseline. After 21 days the first follow-up was conducted and ‘cure rates’ were calculated for all parasites encountered. Eleven months later, the second follow-up assessed longer-term trends. Initial treatments had little, if any, effect on S. stercoralis, and did not alter local prevalence, unlike hookworm infections and intestinal schistosomiasis. We propose that geographical patterns of strongyloidiasis are likely not perturbed by ongoing praziquantel/albendazole campaigns. Antibody titres increased after the first follow-up then regressed towards baseline levels upon second inspection. To better define endemic areas for S. stercoralis, careful interpretation of the ELISA is warranted, especially where diagnosis is likely being confounded by polyparasitism and/or other treatment regimens; new molecular screening tools are clearly needed.

(Accepted August 23 2010)

(Online publication October 20 2010)

Correspondence:

c1 E-mail: r.stothard@nhm.ac.uk