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Background In Kenya, long-distance truck drivers (LDTDs) using the Northern Corridor highway have a high prevalence of HIV and other sexually transmitted infections (STIs) due to their risky sexual networks. However, the spatial distribution of the sexual network locations used by LDTDs is not well understood. Consequently, healthcare stakeholders have found it difficult to provide spatially targeted HIV/STI interventions among LDTDs. Thus, the study sought to establish the spatial distribution of sexual network locations used by LDTDs along the Northern Corridor highway, to inform efficient distribution and use of limited HIV/STI-prevention resources. Methods A cross-sectional study design was used. The study adopted a systematic sampling technique. 296 LDTDs were interviewed using interviewer-administered questionnaires at the Mlolongo weighbridge in Kenya. The LDTDs listed their history of sexual interactions and highway stopovers used during the week preceding data collection. Geospatial modelling techniques, using R statistical software packages for spatial mapping, were employed. Shapefiles were created and overlaid over a map of Kenya using R statistical software to create maps of sexual networks. Results Forty-two highway stopovers used by LDTDs were spatially distributed along the highway, from the Kenya coast to the Kenya–Uganda border. In general, LDTDs' sexual network hotspots were restricted to the outskirts of major cities along the Northern Corridor highway (Nairobi, Mombasa and Nakuru) as well as the Kenya–Uganda international border. Conclusions On the Northern Corridor highway, stopovers situated proximal to major urban areas, as well as those at international border points, frequently serve as sexual network hotspots among LDTDs and their sexual partners. Thus, healthcare stakeholders should improve access to HIV/STI-prevention services targeted for LDTDs at the sexual network hotspots identified in this study. [ABSTRACT FROM AUTHOR]

Environmental modifications disturb the equilibrium of mosquito populations, altering the risk of mosquito-borne diseases. Mosquito distribution, diversity, and bloodmeal sources were examined to compare Rift Valley fever (RVF) risk among irrigated, riverine, and pastoral ecosystems in Bura, Tana River County, Kenya, between September 2014 and June 2015. Thirty-eight households and 21 irrigation fields were selected for the study. Mosquitoes were trapped with carbon dioxide-impregnated CDC traps, one trap per household and three traps per irrigated field, and morphologically identified using taxonomic keys. Host DNA was extracted from engorged females and cytochrome b genes amplified by PCR to identify sources of bloodmeals. A total of 21,015 mosquitoes were collected; 5742 within households in the 3 ecosystems and 15,273 within irrigated fields. Mosquitoes collected within irrigated fields belonged to 8 genera and 37 species, while those from households within the irrigation scheme belonged to 6 genera and 29 species. Collections from riverine and pastoral households belonged to five and four genera, respectively. The most abundant genera in the irrigated fields were Aedes (21%) and Mansonia (22%), while Anopheles (43%) was the most abundant within households. Most mosquitoes in riverine and pastoral households belonged to Anopheles (76%) and Aedes (65%) genera, respectively. Seasonal variation driven by rainfall was evidenced by spikes in mosquito numbers within irrigated and riverine ecosystems. Host species identification revealed that goats and humans were the main sources of bloodmeal. There was an overall increase in mosquito abundance and diversity as a result of the presence of the irrigated ecosystem in this county, and an increased availability of highly RVF-susceptible hosts as a result of the establishment and concentration of residential areas, promoting potential vector-host contacts. These results highlight the impact of anthropogenic changes on mosquito ecology, potentially heightening the risk of transmission and maintenance of RVF in this region.