Effect of Eosin Solution Exposed to Sunlight against Anopheles Mosquito Larvae

ABSTRACT

Mosquitoes are a menace for millions of people around the world, they are vectors for destructive microorganisms which cause diseases like Malaria, Dengue fever and Lymphatic filariasis, affecting people in developing countries and areas with tropical climates. Anopheles, a predominant genus transmits malaria, and the World Health Organization have shown that 350,000 lives especially children and pregnant women are lost annually by it. The aim of this study is to determine the effect of eosin solution exposed to sunlight on larvae of Anopheles mosquito. The use of control method was aid at eliminating the larva stages of the mosquito life cycle. A total of one hundred and twenty (120) Anopheles mosquito larvae were harvested using dipper with handle and net from drainages at Eagle Island and Rivers State University both in Port Harcourt. Five different concentrations of Eosin solutions were prepared in volumes of 1000 microlitre (µl), 800µl, 600µl, 400µl, 200µl after a stock solution of 1gram(g) in 100ml and a control, the physicochemical parameters of the solutions were determined using Extech model DO700 measuring instrument. Twenty (20) mosquito larvae, were carefully introduced into each of the concentrations, exposed to sunlight and observed for 24 hours (hrs) for a period of six (6) days for susceptibility. A hundred percent (100%) mortality was recorded in eosin volume of 1000µl and 800µl. The separate solutions of eosin showed significant effects of their concentrations on the Anopheles mosquito larvae of P-value 0.017 at P<0.05. The result obtained for the physicochemical parameters were; pH 5.24, temperature 30.4oC, conductivity 168µS/cm, salinity 0.08%, total dissolved solids 118 milligram per litre(mg/L) and dissolved oxygen was 6.5mg/L for the control. Changes occurred in the values of the dissolved oxygen before and after exposure to sunlight in all the dilutions. The results obtained showed that after 24 hrs, the mortality rate of the larvae increased, indicating that Anopheles mosquito larvae expose to concentrations of eosin solutions results in their mortality within 48 hrs. It may be concluded that this study has provided some evidence of larvicidal effect of eosin solution exposed to sunlight on larvae of Anopheles mosquito.