Illness and Diseases

In this experiment, 5 grams of OMO detergent was thoroughly mixed with 2 litres of rain waster. Each net was individually immersed in soap solution in a 10-litre water bowl. Nets were then removed from the water bowl then beaten against a concrete slab several times for a total of 10 minutes. Between these beatings, the nets were momentarily soaked in same soap solution for a few seconds when they appeared to run out of dipping water. This was to simulate what happens in the local village. After washing with soap, each net was then rinsed twice for five minutes in same amount of clean water. Each net was washed twice a week. Washing was done mid-morning between 9 to 10 am. After washing and rinsing, nets were dried by hanging under the shade for 4 hours.
Laboratory procedure
Four replicate net samples in templates measuring 30 × 30 cm were cut from each net brand and tested. In total, 20 samples were tested. Each net sample was subjected to a baseline bioassay before washing was started. After the baseline bioassay, samples were washed according to either the standard WHO protocol or a cording to local methods. Thereafter, the samples were washed twice a week. Subsequent bioassays were carried out after every 5th wash on each 2nd day after the previous washing till the 20th wash. Tested samples were stored until after the end of the study for chemical residue analysis. The same samples were used for bioassay and chemical residue analysis. Tested samples were taken as follows; one from the top and three from each of the four sides at random
Bioassays procedures
Four WHO cones were attached to each net sample and a total of 10 mosquitoes were introduced into each cone. 2-5 day old, unfed female laboratory reared susceptible Kisumu strain of Anopheles gambiae mosquitoes was used. At least 40 mosquitoes were exposed on each net for 3 min and then transferred to holding paper cups and provided with 5% sugar solution soaked in absorbent cotton pad. Knockdown was recorded after 30 minutes and 60 minutes after exposure. Mortality was recorded 24 hrs after exposure. Mosquitoes were considered knocked down or dead if they could not fly and could not stand upright on either the side or the bottom of the paper cups. Untreated net was used as a control and was tested each day the bioassay was performed. Tests were done at temperatures of 25°C} 2 and 80%} 10 relative humidity.