Prevalence of soil transmitted nematodes on Nukufetau, a remote Pacific island in Tuvalu

Rick Speare,Wayne Melrose,David Durrheim,Jorg Heukelbach,Sonia Harmen,Falatea Fab Latasi,Tekaai Nelesone

doi:10.1186/1471-2334-6-110

Abstract

BackgroundThe population of Nukufetau, a remote coral atoll island in Tuvalu in the Western Pacific, received annual mass drug administration (MDA) of diethylcarbamazine and albendazole under the Pacific Elimination of Lymphatic Filariasis program in 2001, 2002 and 2003, with the last MDA occurring six months before a cross-sectional survey of the whole population for soil transmitted helminths (STH).MethodsA cross-sectional survey in May 2004 recruited 206 residents (35.2% of the population) who provided a single faecal sample that was preserved, concentrated and examined microscopically.ResultsOverall prevalence of STH was 69.9%; only hookworm and Trichuris trichiura were diagnosed. Trichuris was present in 68.4% with intensity of infection being light in 56.3%, medium in 11.7% and heavy in 0.5%. Hookworm occurred in 11.7% with intensity of infection 11.2% being light and medium in 0.5%. Twenty individuals (9.7%) had dual infections. The prevalence of Trichuris was constant across all ages while the prevalence of hookworm was significantly lower in residents below 30 years of age. In the age group 5–12 years comparison of results with a 2001 survey [1] suggested that the prevalence of STH has declined minimally, due to sustained high prevalence of Trichuris, while hookworm has declined dramatically from 34.4% to 1.6%.ConclusionThe results of this survey suggest that although the MDA appears to have reduced hookworm prevalence in residents below 30 years of age, there has been minimal effect on Trichuris prevalence. An integrated program to control STH is required.

Highlights

The population of Nukufetau, a remote coral atoll island in Tuvalu in the Western Pacific, received annual mass drug administration (MDA) of diethylcarbamazine and albendazole under the Pacific Elimination of Lymphatic Filariasis program in 2001, 2002 and 2003, with the last MDA occurring six months before a cross-sectional survey of the whole population for soil transmitted helminths (STH)
This paper reports the results of a survey for STH amongst all age groups of Nukufetau residents in 2004, three years after the previous school-based survey [1] and following three rounds of MDA using albendazole and DEC
There was no significant difference in prevalence of Trichuris or hookworm infections by gender

Summary

Introduction

The population of Nukufetau, a remote coral atoll island in Tuvalu in the Western Pacific, received annual mass drug administration (MDA) of diethylcarbamazine and albendazole under the Pacific Elimination of Lymphatic Filariasis program in 2001, 2002 and 2003, with the last MDA occurring six months before a cross-sectional survey of the whole population for soil transmitted helminths (STH). A survey of STH in 13 Pacific island countries and territories (PICT) in 2001–2 found a very narrow spectrum of nematode parasites in children with a wide range of prevalences [1]. In this survey, prevalences in children aged 5 to 12 years ranged between 1% and 97% with prevalences lower 5% in Niue and the Cook Islands, but very high prevalences (>80%) on the Marshall Islands, Kiribati, and Tuvalu (Fig 1). One on the main island of Funafuti with a resident population of 4,452, and another on the remote island of Nukufetau, with a resident population of 585

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Conclusion