Field Evaluation of the Bio-Efficacy of Three Pyrethroid Based Coils against Wild Populations of Anthropophilic Mosquitoes in Northern Tanzania

AIMS: This study aims to assess the feeding inhibition and repellency effect of three brands of mosquito coils in experimental huts (East African design). Evaluated products were all pyrethroid-based mosquito coils–Kiboko®, Total® and Risasi®. Mosfly (0.1% D-allethrin) was a positive control. Indoor resting behavior, feeding inhibition and induced exophily were measured as responses of burnt coil smoke in huts. MATERIALS AND METHODS: Resting mosquitoes were collected inside the huts, in window traps and verandah traps using mechanical aspirators. Identified to species level and sex. RESULTS: A total of 1460 mosquitoes were collected, 58.9% (n=860) were Anopheles gambiae s.l while 41.1% (n=600) Culex quinquefasciatus. Indoor resting mosquitoes in all treated huts were significantly reduced than in negative control (DF=4, F=18.6, P < 0.001). Species found to rest indoors were not statistical different between the positive control (Mosfly coil) and other three treated huts (DF=3, F=1.068, P=0.408). Cx.quinquefasciatus had significantly higher induced exophily in all treatments comparing to An.gambiae s./ (DF=1, F=5.34, P=0.050). Comparison between species (An.gambiae s.l and Cx. quinquefasciatus) for the feeding inhibition among treated huts was not statistically significant (DF=1, F=0.062, P=0.810). CONCLUSION: Introduction of several personal protection measures will be ideal to supplement the existing gap in reducing the man vector contacts hence lowering the disease transmission.