MOLECULAR AND BIOASSAY-BASED ASSESSMENT OF TEMEPHOS RESISTANCE IN AEDES LARVAE IN PAKISTAN'S TWIN CITIES

Abstract

Chemical insecticides are still essential for managing dengue and other arboviral disease vectors. With temephos, a neurotoxic organophosphate, being the most commonly used larvicide against Aedes larvae worldwide; larviciding is a crucial part of vector management programs. However, through a variety of mechanisms, the ongoing use of temephos has reduced its effectiveness by causing resistance to emerge in Aedes populations. The present study identifies the presence of the Ace-1 gene linked to organophosphate resistance and assesses Aedes larvae' susceptibility from specific areas of Rawalpindi and Islamabad, Pakistan, to temephos. A study was conducted on Aedes larvae collected from Rawalpindi and Islamabad between February and December 2024. The active ingredient temephos was used in the stock solution, and DNA extraction was performed manually using the SDS method. PCR amplification was used to identify the Ace-1 gene of Aedes, and gel electrophoresis was performed to confirm its presence. Statistical analysis was performed using probit analysis to determine Lethal Concentrations (LC) for the species. The results will inform future research and pest control strategies. According to the biological tests, Aedes larvae from the study sites showed resistance to temephos. Molecular analysis revealed that the Ace-1 gene, a marker for organophosphate resistance, was current. Aedes populations in Rawalpindi and Islamabad have developed a resistance to temephos, according to genetic study and bioassay data. These results highlight the necessity of using a variety of vector management techniques in order to successfully fight dengue and other Aedes-transmitted infections.