DOI: 10.5285/813f99c4-d07a-42dc-993a-1c35df9f028e
title: Seasonal changes in mosquito population densities in irrigated and non-irrigated areas in Bura, Tana River County, Kenya (2013-2014)

description: These data comprise apparent densities, species and sex and of mosquitos collected in irrigated and non-irrigated areas in Bura, Tana River County Kenya, between September 2013 and November 2014. Sampling was repeated four times over the period to cover the wet season, dry season, irrigation season and fallow periods.

Mosquitoes were trapped using carbon dioxide-baited (CDC) light traps. Mosquitoes harvested from each of these traps were immobilized using 99.5% triethyleamine (Sigma-Aldrich, St. Louis, Missouri) and transferred to distinct bar-coded centrifuge tubes or cryogenic vials. The samples were transported in liquid nitrogen to the entomology section of Arbovirus/Viral haemorrhagic fever (VHF) laboratory at the Kenya Medical Research Institute (KEMRI) where they were sorted by species, sex, village, collection date and counted.

The study was implemented to assess the impact of land use change (specifically the conversion of pastoral rangeland into crop land) on the suitability of the habitats to mosquito development and colonization. It also aimed to identify relative abundance of mosquitoes associated with Rift Valley fever virus transmission.

The data were collected and analysed by experienced researchers from the International Centre of Insect Physiology and Ecology (Kenya), the International Livestock Research Institute (Kenya) and the Kenya Medical Research Institute.

This dataset is part of a wider research project, the Dynamic Drivers of Disease in Africa Consortium (DDDAC). The research was funded by NERC project no NE-J001570-1 with support from the Ecosystem Services for Poverty Alleviation Programme (ESPA). Additional funding was provided by the Consultative Group on International Agricultural Research (CGIAR) Program Agriculture for Nutrition and Health.
description: During each visit, mosquitoes were trapped using carbon dioxide-baited (CDC) light traps that were set between 6PM and 6AM for three consecutive days in defined sampling sites (farms and human settlements). All the 10 villages in the Bura irrigation scheme and an additional site outside the scheme (Murukani) were sampled during all these visits. A total of 10 traps were used per village. Each trap was allocated a unique number and mosquitoes harvested from each of these traps were immobilized using 99.5% triethyleamine (Sigma-Aldrich, St. Louis, Missouri) and transferred to distinct bar-coded centrifuge tubes or cryogenic vials. The samples were transported in liquid nitrogen to the entomology section of the VHF laboratory at KEMRI where they were sorted by species, sex, village, collection date and counted. Identified mosquitoes were pooled in sizes of up to 25 per pool and kept in liquid nitrogen for future analyses. Data on mosquito counts per trap-night were entered into a database designed using Microsoft Excel. These data were then converted into a csv file for ingestion purposes.

The data are in their original formats as no transformations or editing has been done. Mosquito speciation and data analysis was supervised by an internationally recognised entomologist for quality assurance.