The study willbe carried out in two sub Counties of HomaBay County namely; Rangwe and Karachuonyo sub Counties. The study targetslocal communities residing within the Oluch-Kimira irrigation scheme and theneighboring communities. Homa Bay County is located in the southern part of formerNyanza Province and lies between latitude 0.
150S and 0.520S and between longitude 340 E and 350E. (Appendix II). According to 2009 Kenya National Population Census, HomaBay County covers an area of approximately 3183.3 Km2 and has apopulation of about 963,794 people.
Homa Bay County experiences semi-aridclimatic conditions where daily temperatures range between 260C and340C during cold months (April and November) and hot months (Januaryto March) respectively. The County receives rainfall ranging between 250mm and1200mm annually. It has two rainy seasons; Long rains (March-April) and shortrains (September- November). With establishment of irrigation scheme andconstruction of dams, local communities have adopted mixed crop farming. Somegrow rice, water melon, maize, while others plant vegetables. The study area will be sub-divided into threetransmission zones based on proximity to irrigation scheme.
The threetransmission zones include; High transmission zone denoted “H” (areas withinirrigation schemes), medium transmission zones “M” (areas located 2-3 KM awayfrom the irrigation scheme and low transmission zones “L” (areas located 5-10km away from the scheme. (Appendix III). The region experience perennialmalaria transmission (MOH, 2014; Mohajan, 2014; MOH, 2016b, 2016a). 3.2. Study designThe study will be both cross-sectional andlongitudinal in survey. Cross-sectional survey will be conducted three times peryear for two years.
It will be carried out in the dry season (January-February 2018), longrain season (April-May) and short rain season (October-November). The samecycle will be repeated in the year 2019 (Appendix IV). Study participants aged6 months and above in every household will be recruited. During each survey,finger prick blood sample from each study participant will be collected.The sample will be examined for infections with Plasmodium spp. and gametocyte carriage using microscopy and PCR. During longitudinal survey(active case detection), finger prick blood sample for both microscopy andmolecular examination will be collected after every two weeks for one year in allstudy clusters. For each study participant, parasitaemia density, anaemiaand body temperature will be determined.
Before commencement of the survey,community members will be recruited into the study. Each household will beregistered into the study after explaining the study purpose, rationale andmethods to the household heads and their family members. Written informedconsent will be sought from the head of the household, while verbal consentwill be obtained from other family members to participate in the study.Following enrollment, all households will be geo-located using GPS (Garmin,Switzerland) instruments with up to 5 m of accuracy.
Demographic informationsuch as age, level of education, source of income and gender will be collectedfrom the head of the family.3.3.
Sampling techniqueCluster sampling will be used to divide the study areainto clusters. A Swiss cheese pattern of clusters within the catchments will bedefined based on geographic and land characteristics (e.g., a group of isolatedhouses, villages or sections of a township) and the boundary of each clustermarked. Cluster radii will vary from 0.25 – 0.
5 km and with populations rangingfrom 100-250 residents. A malaria risk index will be computed for each clusterbased on proximity to breeding sites, vegetation coverage, and other ecologicfactors. A total of 12 clusters will be identified. The study area will beclassified into three transmission sites (high risk area, medium risk area andlow risk area) based on risk index.
For instance, high risk area (within theirrigation scheme), medium risk area (2-3 KM to the irrigation scheme) and lowrisk area (5-10 KM to the irrigation scheme). Four clusters will be identifiedwithin each transmission site. In each cluster, fifty households will beenrolled into the study.