Malaria in Kakuma refugee camp, Turkana, Kenya: facilitation of Anopheles arabiensis vector populations by installed water distribution and catchment systems

Malaria Journal

Research

M Nabie Bayoh¹  Maurice Ombok¹  Mary J Hamel²  Heather Burke³  Robert Breiman⁴  Edward D Walker⁵  Willis Akhwale⁶  David Sang⁷  Gregory L Armstrong⁸  Michelle Weinberg⁸  Martin S Cetron⁸  Holly A Williams⁸  Sammy C Engoki⁹  Dan Koros⁹ 

[1] Centre for Global Health Research, Kenya Medical Research Institute/Centres for Disease Control and Prevention, P.O. Box 1578, Kisumu, Kenya;Centre for Global Health Research, Kenya Medical Research Institute/Centres for Disease Control and Prevention, P.O. Box 1578, Kisumu, Kenya;Centers for Disease Control and Prevention, Malaria Branch, 1600 Clifton Road, Mailstop F-22, 30301, Atlanta, GA, USA;Centre for Global Health Research, Kenya Medical Research Institute/Centres for Disease Control and Prevention, P.O. Box 1578, Kisumu, Kenya;International Emergency and Refugee Health Branch, Centres for Disease Control and Prevention, 1600 Clifton Rd, 30333, Atlanta, Georgia, USA;Centres for Disease Control and Prevention, International Emerging Infections Programme, Mbagathi Way, Nairobi, Kenya;Department of Microbiology and Molecular Genetics, Michigan State University, 48824, East Lansing, Michigan, USA;Division of Malaria Control, Ministry of Health, Nairobi, Kenya;Division of Malaria Control, Ministry of Health, Nairobi, Kenya;Kenya Methodist University, Meru, Kenya;International Emergency and Refugee Health Branch, Centres for Disease Control and Prevention, 1600 Clifton Rd, 30333, Atlanta, Georgia, USA;International Rescue Committee, Kakuma Refugee Camp, Kenya;

关键词: Malaria;    Malaria Vector;    Attack Rate;    Larval Habitat;    Kitchen Garden;   

DOI  :  10.1186/1475-2875-10-149

 received in 2011-03-11, accepted in 2011-06-04,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundMalaria is a major health concern for displaced persons occupying refugee camps in sub-Saharan Africa, yet there is little information on the incidence of infection and nature of transmission in these settings. Kakuma Refugee Camp, located in a dry area of north-western Kenya, has hosted ca. 60,000 to 90,000 refugees since 1992, primarily from Sudan and Somalia. The purpose of this study was to investigate malaria prevalence and attack rate and sources of Anopheles vectors in Kakuma refugee camp, in 2005-2006, after a malaria epidemic was observed by staff at camp clinics.MethodsMalaria prevalence and attack rate was estimated from cases of fever presenting to camp clinics and the hospital in August 2005, using rapid diagnostic tests and microscopy of blood smears. Larval habitats of vectors were sampled and mapped. Houses were sampled for adult vectors using the pyrethrum knockdown spray method, and mapped. Vectors were identified to species level and their infection with Plasmodium falciparum determined.ResultsPrevalence of febrile illness with P. falciparum was highest among the 5 to 17 year olds (62.4%) while malaria attack rate was highest among the two to 4 year olds (5.2/1,000/day). Infected individuals were spatially concentrated in three of the 11 residential zones of the camp. The indoor densities of Anopheles arabiensis, the sole malaria vector, were similar during the wet and dry seasons, but were distributed in an aggregated fashion and predominantly in the same zones where malaria attack rates were high. Larval habitats and larval populations were also concentrated in these zones. Larval habitats were man-made pits of water associated with tap-stands installed as the water delivery system to residents with year round availability in the camp. Three percent of A. arabiensis adult females were infected with P. falciparum sporozoites in the rainy season.ConclusionsMalaria in Kakuma refugee camp was due mainly to infection with P. falciparum and showed a hyperendemic age-prevalence profile, in an area with otherwise low risk of malaria given prevailing climate. Transmission was sustained by A. arabiensis, whose populations were facilitated by installation of man-made water distribution and catchment systems.

【 授权许可】

CC BY   
© Nabie Bayoh et al; licensee BioMed Central Ltd. 2011