title: Risk factors and spatial distribution of Schistosoma mansoni infection among primary school children in Mbita District, Western Kenya.
abstract: BACKGROUND
  An increasing risk of Schistosoma mansoni infection has been observed around Lake Victoria, western Kenya since the 1970s. Understanding local transmission dynamics of schistosomiasis is crucial in curtailing increased risk of infection.
  
  
  RESULTS
  We carried out a cross sectional study on a population of 310 children from eight primary schools. Overall, a total of 238 (76.8%) children were infected with S. mansoni, while seven (2.3%) had S. haematobium. The prevalence of hookworm, Trichuris trichiura and Ascaris lumbricoides were 6.1%, 5.2% and 2.3%, respectively. Plasmodium falciparum was the only malaria parasite detected (12.0%). High local population density within a 1 km radius around houses was identified as a major independent risk factor of S. mansoni infection. A spatial cluster of high infection risk was detected around the Mbita causeway following adjustment for population density and other potential risk factors.
  
  
  CONCLUSIONS
  Population density was shown to be a major factor fuelling schistosome infection while individual socio-economic factors appeared not to affect the infection risk. The high-risk cluster around the Mbita causeway may be explained by the construction of an artificial pathway that may cause increased numbers of S. mansoni host snails through obstruction of the waterway. This construction may have, therefore, a significant negative impact on the health of the local population, especially school-aged children who frequently come in contact with lake water.
authors: Department of Parasitology, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan; Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors: Sachiyo
authors: S
authors: Nagi
authors: Department of Parasitology, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan.
authors: Evans A
authors: EA
authors: Chadeka
authors: Department of Vector Biology and Environment, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan.
authors: Toshihiko
authors: T
authors: Sunahara
authors: Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
authors: Faith
authors: F
authors: Mutungi
authors: Department of Parasitology, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan; Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors: Yombo K Dan
authors: YK
authors: Justin
authors: Department of EcoEpidemiology, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan.
authors: Satoshi
authors: S
authors: Kaneko
authors: Nagasaki University Nairobi Research Station, NUITM-KEMRI Project, Nairobi, Kenya.
authors: Yoshio
authors: Y
authors: Ichinose
authors: Department of Infectious Disease Control and International Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Sohkichi
authors: S
authors: Matsumoto
authors: Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
authors: Sammy M
authors: SM
authors: Njenga
authors: Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan.
authors: Masahiro
authors: M
authors: Hashizume
authors: Department of EcoEpidemiology, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan; Nagasaki University Nairobi Research Station, NUITM-KEMRI Project, Nairobi, Kenya.
authors: Masaaki
authors: M
authors: Shimada
authors: Department of Parasitology, Institute of Tropical Medicine, Nagasaki University (NUITM), Nagasaki, Japan; Nagasaki University Nairobi Research Station, NUITM-KEMRI Project, Nairobi, Kenya.
authors: Shinjiro
authors: S
authors: Hamano
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012555:Schistosomiasis mansoni / Q000453:epidemiology* / Q000469:parasitology; D012574:Schools; D013334:Students / Q000706:statistics & numerical data*; D055815:Young Adult