title: High and Heterogeneous Prevalence of Asymptomatic and Sub-microscopic Malaria Infections on Islands in Lake Victoria, Kenya.
abstract: Kenya is intensifying its national efforts in malaria control to achieve malaria elimination. Detailed characterization of malaria infection among populations living in the areas where the disease is endemic in Kenya is a crucial priority, especially for planning and evaluating future malaria elimination strategy. This study aimed to investigate the distribution and extent of malaria infection on islands in Lake Victoria of Kenya to aid in designing new interventions for malaria elimination. Five cross-sectional surveys were conducted between January 2012 and August 2014 on four islands (Mfangano, Takawiri, Kibuogi and Ngodhe) in Lake Victoria and a coastal mainland (Ungoye). Malaria prevalence varied significantly among settings: highest in Ungoye, followed by the large island of Mfangano and lowest in the three remaining small islands. Of the 3867 malaria infections detected by PCR, 91.8% were asymptomatic, 50.3% were sub-microscopic, of which 94% were also asymptomatic. We observed geographical differences and age dependency in both proportion of sub-microscopic infections and asymptomatic parasite carriage. Our findings highlighted the local heterogeneity in malaria prevalence on islands and a coastal area in Lake Victoria, and provided support for the inclusion of mass drug administration as a component of the intervention package to eliminate malaria on islands.
authors.affiliation: Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden.|Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, 56000, Malaysia.
authors.forename: Zulkarnain Md
authors.initials: ZM
authors.lastname: Idris
authors.affiliation: Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden.
authors.forename: Chim W
authors.initials: CW
authors.lastname: Chan
authors.affiliation: Nagasaki University Nairobi Research Station, NUITM-KEMRI Project, Nairobi, 00202, Kenya.
authors.forename: James
authors.initials: J
authors.lastname: Kongere
authors.affiliation: Department of Clinical Medicine, Mount Kenya University, Thika, 01000, Kenya.
authors.forename: Jesse
authors.initials: J
authors.lastname: Gitaka
authors.affiliation: National Malaria Control Programme, Ministry of Public Health and Sanitation, Nairobi, 00100, Kenya.
authors.forename: John
authors.initials: J
authors.lastname: Logedi
authors.affiliation: National Malaria Control Programme, Ministry of Public Health and Sanitation, Nairobi, 00100, Kenya.
authors.forename: Ahmeddin
authors.initials: A
authors.lastname: Omar
authors.affiliation: Kenya Medical Research Institute (KEMRI), Centre for Global Health Research, Kisumu, 40100, Kenya.
authors.forename: Charles
authors.initials: C
authors.lastname: Obonyo
authors.affiliation: National Malaria Control Programme, Ministry of Public Health and Sanitation, Nairobi, 00100, Kenya.
authors.forename: Beatrice Kemunto
authors.initials: BK
authors.lastname: Machini
authors.affiliation: Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Isozumi
authors.affiliation: Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Teramoto
authors.affiliation: Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kimura
authors.affiliation: Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17177, Sweden.|Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, 558-8585, Japan.|Institute of Tropical Medicine, Nagasaki University, Nagasaki, 852-8102, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kaneko
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D062312:Islands / Q000453:epidemiology; D007630:Kenya / Q000453:epidemiology; D008288:Malaria / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D010961:Plasmodium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D055815:Young Adult