Prevalence of plasmodium species infection among primary school children and performance of malaria rapid diagnostic test kits in Baringo county, Kenya.

Malaria causes the greatest public health burden in sub-Saharan Africa where high mortality mainly occurs in children under five years of age and pregnant women. Majority of Kenyan population are at risk of malaria infection. Traditionally, malaria has been studied mainly in Western and Coastal Kenya while the rift valley especially Baringo County few malaria studies have been conducted indicating seasonal transmission. This has resulted in scanty information on actual malaria prevalence and transmission patterns which may hinder setting up of proper control strategies. Moreover, primary school children seem to be endangered due to minimal protection by insecticide treated nets. The purpose of this study was to determine the prevalence of Plasmodium species infection among primary school children and to evaluate the performance of malaria rapid diagnostic test kits in diagnosis of malaria in Baringo County, Kenya. One thousand six hundred and sixty eight (1668) children from fifteen primary schools located in 4 ecological zones (lowlands, midlands, highlands and riverine) of three sub-Counties of Baringo County were recruited into the study. Finger prick blood sampling was done every four months (during the dry season in January/ February, during the long rains in June/July, short rains in November 2015 and during dry season in January/ February 2016). Plasmodium species infection was tested using three rapid diagnostic test kits (CareStart Pf, SD Bioline Ag Pf and SD Bioline Ag P.f/ Pan). Microscopic examination was done on all RDT positive and 10% of negative cases. A total of 268 (16.1%), out of 1668 pupils tested positive for P. falciparum by RDT; 78% had a single episode of infection, 16.8% had 2 episodes, 4.9% had 3 episodes and 0.4% had 4 episodes of infections. Plasmodium species infection varied within local ecological zones. For instance, the riverine zone had the highest cases of Plasmodium species infection compared to lowland, highland and midland (Fisher’s exact test = 0.005). More cases of Plasmodium species infection (10.7 and 6.2%) were reported in dry season compared to 2.6% in the long rains (Fisher’s exact test= 1.000) and 5.7% in short rains (Fisher’s exact test= 0.197). Risk of Plasmodium species infection was significantly higher in riverine zone compared to midland, lowland and highland (IRR= 40.24165 (95% CI: 7-1623). Infection rate for males and females was similar (IRR = 1.02 (95% CI: 0.55-1.88). The study also established that children aged between 10 – 15 years were at higher risk of Plasmodium species infection than those aged between 5- 9 (IRR 1.6 (95% CI: 0.9- 3.1). The kits performed relatively well in the diagnosis of malaria using microscopy as reference. SD Bioline Ag-Pf/ Pan RDT kit had a higher sensitivity (90%) compared to that of CareStart Pf (70%) (McNemar's χ² = 0.5, df = 1, p-value = 0.4795). Similarly, the sensitivity of SD Bioline Pf was the same as that of CareStart Pf (82.4%). The kits can therefore be used to guide treatment of febrile illness within Baringo County. In addition, present study findings, indicate that Plasmodium species infection was relatively low within Baringo County compared to endemic regions of Kenya; however, there is a need for continued monitoring of transmission dynamics under changing climatic conditions as well as establishing expanded malaria control strategies especially within the riverine zone.
A thesis submitted in partial fulfillment of the requirements for the award of the degree of master of science (applied parasitology) in the school of pure and applied sciences of Kenyatta University.