Evaluation of pure camphor (C10H16O) against wild-caught Culex quinquefasciatus larvae in East Jakarta, Indonesia: Detoxification enzymes and histopathological midgut

Abstract

Filariasis, transmitted by the lymphatic filariasis vector Culex quinquefasciatus, is still a global public health issue. Resistance to Cx. quinquefasciatus is caused by the eradication of filariasis with synthetic insecticides. The aim of the study was to evaluate the toxicity of pure camphor on Cx. quinquefasciatus, with a focus on detoxifying enzymes and midgut histopathological abnormalities. Cx. quinquefasciatus larvae are field-collected wild-strain larvae. The WHO protocol was followed for the larval bioassays. Pure camphor concentrations of 0.5, 1.5, 10.5, 25.5, and 50 ppm were applied to larvae for 24, 48, and 72 h, with 5 replications. The biochemical method was used to test detoxification enzymes such as acetylcholinesterase (AChE), glutathione S-transferase (GST), and oxidase. The routine histopathological examination was performed on the larvae's histopathological midguts. At 48 h, pure camphor caused 100% mortality of Cx. quinquefasciatus larvae. LC50 and LC90 values were found to be 2.32 and 12.40 ppm respectively. AChE and oxidase activity were both significantly lower (p