Entomological surveillance on Aedes aegypti during covid 19 period in Cape Coast, Ghana: Risk of arboviral outbreaks, multiple insecticide resistance and distribution of F1534C, V410L and V1016I kdr mutations

Abstract

Background The study assessed the risk of transmission of Aedes-borne arboviruses in a community at Cape Coast during the Covid-19 restriction period in 2020 based on entomological indices. The spatial distribution of insecticide resistance was also assessed in Ae. aegypti population from Cape Coast. Methods Three larval indices were calculated from a household larval survey in 100 randomly selected houses. WHO susceptibility bioassay was performed on female adult Ae. aegypti that were reared from the larvae collected from household containers and other receptacles located outside houses against four insecticides. The mosquitoes were also screened for F1534C, V1016I, and V410L kdr mutations. Results The estimated larval indices in the study community were House index– 34%, Container index– 22.35%, and Breteau index– 2.02. The mosquito population was resistant to Deltamethrin (0.05%), DDT (4%), Fenitrothion (1%), and Bendiocarb (0.1%). A triple kdr mutation, F1534C, V410L and V1016I were detected in the mosquito population. Conclusion The study found the risk of an outbreak of Aedes-borne diseases lower in the covid-19 lockdown period than before the pandemic period. The low risk was related to frequent clean-up exercises in the community during the Covid-19 restriction period. Multiple insecticide resistance couple with three kdr mutations detected in the study population could affect the effectiveness of control measures, especially in emergency situations. The study supports sanitation improvement as a tool to control Ae. aegypti and could complement insecticide-based tools in controlling this vector.

Impact of the exposure of sublethal dose of mosquito coil on the development of insecticide resistance in Aedes aegypti (L.) (Diptera: Culicidae)

“…A combination of F1534C and V1016I have been reported to confer higher resistance to pyrethroid insecticides than F1534C alone (Moyes et al, 2017). In this study, the frequency of F1534C kdr mutation was high in the exposed and control colonies, which is consistent with what is found in the wild population in Ghana (Ablorde et al, 2023;Ayettey et al, 2023;Kudom, 2020). However, the frequency of the 1016I resistant allele was higher in the exposed colony than the control.…”

“…The F1534C mutation is the most widely distributed kdr mutation and close to fixation in many parts of the country (Ablorde et al, 2023;Amlalo et al, 2022;Ayettey et al, 2023). A combination of F1534C and V1016I have been reported to confer higher resistance to pyrethroid insecticides than F1534C alone (Moyes et al, 2017).…”

“…The mosquito population is resistant to various pyrethroid insecticides (Kudom, 2020) as well as to DDT (organochlorine), bendiocarb (carbamate) and shows moderate resistance to fenitrothion (organophosphate) insecticides. Three target-site mutations (F1534C, V1016I and V410I) as well as metabolic mechanisms have been detected in the population (Ayettey et al, 2023;Kudom, 2020). The colony was raised to the seventh generation and subsequently used for the test in this study.…”

Upsurge of dengue outbreaks in several WHO regions: Public awareness, vector control activities, and international collaborations are key to prevent spread

“…Household water storage methods play a crucial role in dengue outbreaks 40,41 . As breeding habitats, Aedes mosquitoes utilize various receptacles, such as buckets, jars, and abandoned tires 42 . These mosquitoes prefer depositing their eggs in small, dimly lit receptacles containing stagnant water.…”

“… 40 , 41 As breeding habitats, Aedes mosquitoes utilize various receptacles, such as buckets, jars, and abandoned tires. 42 These mosquitoes prefer depositing their eggs in small, dimly lit receptacles containing stagnant water. The absence of a dependable piped water supply in certain regions amplifies the issue due to the increased need for water storage.…”