Since insecticides are commonly used in agriculture/cultivation and in vector control, they are frequently found in agricultural water bodies, where mosquito larvae are exposed. Although their concentration is often so low as not to kill the larvae, they affect the development of the mosquitoes. In particular, their effects may be transmitted to adults to influence their characteristics of life-history and their vectorial competence for arboviruses infection and malaria. Such effects on vectorial competence of sub-lethal doses of insecticides are likely to be related to their impact on immune response. Insecticide exposure influences the immune response of insects in several ways. Organophosphates and organochlorines affect the number of hemocytes (for phagocytosis) However, it is not known whether larvae exposure will impact the immune response of adults.
Assessment of the bio-efficacy and residual activities of insecticides sprayed, wall surface using CDC wall cone bioassay test. Entomological indices with Anopheles species collection was measured to determined vectorial involvement and residual bio-efficacy of of Inesfly 5AIGR/ Inesfly 5AIGRNG insecticidal paints on Adult Anopheles gambiae complex mosquitoes on treated wall surfaces in at both communities (Masaka and Gidan Zakara) from January to April and May through June, 2018. A bio-assay cone test was carried out at various wall surfaces/height treated with above named insecticidal paints at parameters of 0.5meter, 1meter, and 1.5meter respectively.
In both communities the knockdown/mortality threshold fluctuates (94%-99%.) indicating the state of resistance and susceptible, however, in the month of May and June at Gidan-Zakara, the knockdown/mortality of mosquitoes after 24hrs was 90%-100%.The seasonal abundance of mosquito population was generally observed to decrease between the month of January through April, 2018 and increases during the onset of rains in the months of April through June, 2018. There was no significance difference in the seasonal abundance of mosquitoes and the efficacy of Inesfly 5AIGR and Inesfly 5AIGRNG insecticide paints (F= 0.958> 0.435 and F 1.515>0.293. Similarly no significant difference in the residual efficacy and the malaria vector mortality (F=2.286>0.183) and in June (F1.549>0.287). The residual Inesfly paints were effective, given that 98%-100% malaria vector were susceptible.
The malaria vectorial competence of Anopheles species were 98% - 100% susceptible to residual ‘1NESFLY’ paints (5AIGR and 5AIGRNG) at various wall parameters of 0.5meters, 1meter and 1.5meters in the studied communities in central Nigetia. It is also imperative to state that the trial paints were in compliance with animals and human tolerance levels/standards during the during the trial periods, and fulfils the WHO criteria of insecticidal bio-efficacy (mortality >80%).