Resistance status of main malaria vector, Liston (Diptera:Culicidae) to insecticides in a malaria Endemic Area,Southern Iran

Objective: To evaluate the susceptibility of Anopheles stephensi(An. stephensi) Liston, the main malaria vector in southern Iran, to WHO recommended insecticides. Methods: Larvae of An. stephensi were collected from three different larval habitats in both urban and rural area of Bandar Abbas city and one rural area in Rudan county southern Iran. WHO standard method was used for evaluation of adult and larval mosquito susceptibility. Bendiocarb, permethrin, lambda-cyhalothrin, deltamethrin as insecticide and temephos and chlorpyriphos as larvicide were used at the diagnostic dosages recommended by WHO. Results: Findings of this study showed all larval populations of An. stephensi were completely susceptible to temephos and candidate for resistance to chlorpyriphos. Adult mosquitoes in rural areas of Bandar Abbas city were resistant to pyrethroid and carbamate insecticides. Conclusion: Comparison of the results of this survey with previous studies indicates that the resistance to pyrethroids and carbamates in this malaria endemic region is increasing. Wide use of pesticides in agriculture is certainly effective in increasing resistance. The inter-sectoral coordination and collaboration in health and agriculture seem to be necessary to manage insecticide resistance in malaria vectors.

The impact of climatic variables on the population dynamics of the main malaria vector, Anopheles stephensi Liston(Diptera: Culicidae), in southern Iran

Objective:To determine the significance of temperature,rainfall and humidity in the seasonal abundance of Anopheles stephensi in southern Iran.Methods:Data on the monthly abundance of Anopheles stephensi larvae and adults were gathered from earlier studies conducted between 2002 and 2019 in malaria prone areas of southeastern Iran.Climatic data for the studied counties were obtained from climatology stations.Generalized estimating equations method was used for cluster correlation of data for each study site in different years.Results:A significant relationship was found between monthly density of adult and larvae of Anopheles stephensi and precipitation,max temperature and mean temperature,both with simple and multiple generalized estimating equations analysis(P<0.05).But when analysis was done with one month lag,only relationship between monthly density of adults and larvae of Anopheles stephensi and max temperature was significant(P<0.05).Conclusions:This study provides a basis for developing multivariate time series models,which can be used to develop improved appropriate epidemic prediction systems for these areas.Long-term entomological study in the studied sites by expert teams is recommended to compare the abundance of malaria vectors in the different areas and their association with climatic variables.