Integrity, Use, and Care of Treated Mosquito Nets in Kirinyaga County, Kenya

Background: Vector control is an essential component in prevention and control of malaria in malaria endemic areas. Insecticide treated nets is one of the standard tools recommended for malaria vector control. The objective of the study was to determine physical integrity and insecticidal potency of long-lasting insecticidal nets (LLINs) used in control of malaria vector in Kirinyaga County, Kenya.Method: The study targeted households on an area which had received LLINs during the mass net distribution in 2016 from ministry of health. A total of 394 households were sampled using systematic sampling method with a random start, where the household heads consented to participate in the study. A semi-structured questionnaire was administered to assess physical integrity, care and use. Chemical potency was analysed in the laboratory by use of gas chromatography mass spectroscopy (GC-MS). Data analysis was done using Statistical Package for Social Sciences (SPSS) version 19. Results: After eighteen months of use, 97.8% (95% CI: 96.4% – 99.3%) of the distributed nets were still available. Regarding the net utilization, 93.7% of household heads reported sleeping under an LLIN the previous night. After physical examination, 47.9% (95% CI: 43% - 52.8%) of the bed nets had at least one hole. The median number of holes of any size was 2 [interquartile range (IQR) 1-4], and most holes were located on the lower part of the nets, [median 3 (IQR 2-5)]. Only 6.4% of the nets with holes had been repaired. The median concentration for alpha-cypermethrin was 7.15mg/m2 (IQR 4.25-15.31) and 0.00mg/g (IQR 0.00-1.99) for permethrin. Based on pHI Chi-square test results shows that net physical status varied significantly with the manufacturer There was no significant difference of chemical content between nets with different number of washes . Conclusion: The current study results shows that more than three-quarters of the nets supplied had survived and had insecticidal potency which was adequate in vector control. According to WHO classification 14.2% of nets supplied were too torn and required immediate replacement. In addition, studies for validated methods are needed to better understand field evaluation of surface insecticidal content available to a mosquito after landing on a bed net to rest.