Elimination of lymphatic filariasis as a public health problem from the Cook Islands

Charlie Ave,Eric Ottesen,D Ramaiah Kapa

doi:10.1186/s41182-018-0094-9

Charlie Ave, Eric Ottesen + Show 1 more

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https://doi.org/10.1186/s41182-018-0094-9

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Abstract

BackgroundThe Cook Islands has a long history of high-endemicity lymphatic filariasis (LF) transmitted by Aedes vector mosquitoes. Though the infection prevalence had declined between 1975 and 1999 following episodic treatment activities, still infection was widespread with pockets of persistent infection. Beginning in 1999, the Cook Islands embarked on a national program, in partnership with Pacific Programme to Eliminate LF (PacELF), to eliminate LF as a public health problem.MethodsAll 12 inhabited islands were identified as endemic, and six rounds of mass drug administration (MDA) with once-yearly, single-dose albendazole plus diethylcarbamazine (DEC) were implemented during 2000–2006 to interrupt transmission of LF. Surveys carried out at the baseline, mid-term, stop-MDA, and post-MDA periods assessed LF antigen (Ag) prevalence in children and adults. Historical data, health workers’ observations, and hospital records were used to assess the trend and burden of chronic disease.ResultsThe baseline Ag prevalence (1999) ranged from 2.0% in Manihiki to > 18.0% in Aitutaki, Mitiaro, and Pukapuka, and the national average Ag prevalence was 8.6%. MDA, carried out with a national treatment coverage over six annual rounds of MDA ranging from 63.5 to 96.7% in different years, was stopped in 2007. By then, the national Ag prevalence had declined to 0.27%. The post-MDA surveillance survey results (2013–2014) showed that Ag prevalence had fallen to 0% in 11/12 islands, and the national prevalence was only 0.03%. Chronic filarial disease had almost entirely disappeared.ConclusionThe Cook Islands met all the criteria required for the World Health Organization (WHO) to acknowledge elimination of LF as a public health problem, as it did officially in 2016. This success also confirms that LF, even when transmitted by Aedes mosquitoes that are recognized to be more efficient than other vector species, can be eliminated as a public health problem by six rounds of MDA.

Highlights

The Cook Islands has a long history of high-endemicity lymphatic filariasis (LF) transmitted by Aedes vector mosquitoes
The epidemiology of LF in the region is notable for (i) its transmission by the day-biting Aedes mosquito species that are more efficient than other mosquito vectors of LF [3] and (ii) its distribution of infection being very widely scattered among the islands and atolls of different countries of the region
Goals and objectives of programme to eliminate LF In March 1999, at meetings of the Pacific Regional Ministers convened by the Western Pacific Regional Office (WPRO) of the World Health Organization (WHO) and by the Secretariat of the Pacific Community (SPC), 22 nations with histories of LF agreed to initiate activities to support the 1997 World Health Assembly Resolution calling for the elimination of LF as a public health problem

Summary

Introduction

The Cook Islands has a long history of high-endemicity lymphatic filariasis (LF) transmitted by Aedes vector mosquitoes. Lymphatic filariasis (LF) has been recognized for decades as a significant public health problem in the countries of the South Pacific, with 16 countries in the region, including the Cook Islands, still endemic in 2000 [1, 2]. The epidemiology of LF in the region is notable for (i) its transmission by the day-biting Aedes mosquito species that are more efficient than other mosquito vectors of LF [3] and (ii) its distribution of infection being very widely scattered among the islands and atolls of different countries of the region. The goals, objectives, activities, and impact of the program are presented in this paper

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