Risk Factors and Spatial Distribution of Schistosoma mansoni Infection among Primary School Children in Mbita District, Western Kenya

Abstract

BackgroundAn 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.Methodology/Principal FindingsWe 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/SignificancePopulation 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.

Prevalence, infection intensity and associated risk factors of Intestinal Schistosomiasis among primary school Children in Lira District, Northern Uganda

“…This is categorized as moderate risk [19]. This prevalence is low compared to those obtained from western Kenya (76.8%), and in Tanzania (64.3%) [24,26]. This low prevalence in Lira district could be due to the massive administration of preventive chemotherapeutic praziquantel (in Aromo subcounty only) and…”

Distribution of Biomphalaria Snails in Associated Vegetations and Schistosome Infection Prevalence Along the Shores of Lake Victoria in Mbita, Kenya: A Cross-Sectional Study

“…The HDSS in Mbita follows 11,182 households with a population of 55,929 individual. 7 The ethnic group in this area is predominantly Luo (98%). There are 30 health facilities within the study area.…”

“…6 Previous studies among school children in Mbita and its adjacent islands of Lake Victoria have shown the prevalence to be 63.3% and 60.5%, respectively. 7,8 Schistosomiasis has a great impact on the quality of life of individuals with important implication on the economy. 9 S. mansoni infection is known to lower cognitive development in children thereby lowering their academic performance in school and reduce work force in adults.…”

Understanding wetlands reclamation and soil-transmitted helminths and schistosomiasis incidence patterns in Rwanda (2001-2012)

“…However, the district level is not small enough for detecting highly focalized schistosomiasis infection hotspots, often with transmission risk areas corresponding to 1km around the houses (Nagi et al, 2014) or 5 km, as maximum distance, around infected wetland sites (Handzel et al, 2003;Hu et al, 2013). The advantage of Rwanda remains on temporal resolution (historical data with high quality and a stable HMIS for more than ten years) and on higher geographical density of health facilities.…”