Journal Article

Diagnosis, Treatment and Risk Factors of Strongyloides stercoralis in Schoolchildren in Cambodia

Marti, Hanspeter, Duong, Socheat, Schär, Fabian, Sayasone, Somphou, Odermatt, Peter, Muth, Sinuon, Khieu, Virak

2013

Overview

Worldwide, an estimated 30 to 100 million people are infected with Strongyloides stercoralis, a soil-transmitted helminth. Information on the parasite is scarce in most settings. In semi-rural Cambodia, we determined infection rates and risk factors; compared two diagnostic methods (Koga agar plate [KAP] culture and Baermann technique) for detecting S. stercoralis infections, using a multiple stool examination approach; and assessed efficacy of ivermectin treatment. We performed a cross-sectional study in 458 children from four primary schools in semi-rural villages in Kandal province, using three diagnostic procedures (Kato-Katz, KAP culture and Baermann technique) on three stool samples. Infected children were treated with ivermectin (100 µg/kg/day for two days) and re-examined three weeks after treatment. Hookworm, S. stercoralis, Trichuris trichiura, and small trematode eggs were most prevalent, with 24.4% of children being infected with S. stercoralis. The sensitivity of KAP culture and Baermann technique was 88.4% and 75.0%, respectively and their negative predictive values were 96.4% and 92.5%, respectively. The cumulative prevalence of S. stercoralis increased from 18.6% to 24.4%, after analyzing three stool samples, which was close to the modeled 'true' prevalence of 24.8%. Children who reported defecating in latrines were significantly less infected with S. stercoralis than those who did not use latrines (p<0.001). Itchy skin and diarrhea were significantly associated with S. stercoralis infection. The cure rate of ivermectin was 98.3%. S. stercoralis infection is highly prevalent among semi-rural Cambodian schoolchildren. The sensitivity of KAP culture is higher than that of the Baermann technique. In the absence of a \"gold standard\", analysis of multiple stool samples by different diagnostic methods is required to achieve a satisfactory level of sensitivity. Almost three-quarters of the infections could have been avoided by proper sanitation. Ivermectin is highly efficacious against S. stercoralis but prohibitive costs render the drug inaccessible to most Cambodians.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adolescent / Ancylostomatoidea - isolation & purification / Animals / Anthelmintics - therapeutic use / Cambodia - epidemiology / Care and treatment / Child / Cross-Sectional Studies / Diagnosis / Diagnostic Tests, Routine - methods / Drug dosages / Elementary school students / Feces - parasitology / Female / Health aspects / Humans / Hygiene / Infections / Ivermectin - therapeutic use / Male / Medical research / Medicine / Parasites / Parasitology - methods / Predictive Value of Tests / Prevalence / Risk Factors / Schools / Sensitivity and Specificity / Strongyloides stercoralis - isolation & purification / Strongyloidiasis / Strongyloidiasis - diagnosis / Strongyloidiasis - drug therapy / Strongyloidiasis - epidemiology / Studies / Treatment Outcome / Trichuris - isolation & purification / Tropical diseases / Young Adult