Impact of bendiocarb 80% WP indoor residual spraying on insecticide resistance status of Anopheles arabiensis

Abstract

Long term and wide use of indoor residual sprays augments the selection of insecticide resistance genes. The development of insecticide resistance in an insect population depends up on the volume and frequency of sprays against them and the inherent characteristics of the insect species. However, despite its use for decades, the effect of residual sprays on the status of insecticide resistance of malaria vectors is unknown in Ethiopia. The objective of this study was to assess the effect of bendiocarb 80% WP indoor residual spraying on insecticide resistance status of An. arabiensis in Bahir Dar Zuria District, Northwest Ethiopia. Susceptibility of An. arabiensis was examined against different insecticides using 2-3-day old female mosquitoes following WHO insecticide susceptibility test procedures. Test results were calculated according to WHO bioassay test protocol. Chi-square test was used to determine the significance level of differences between years and study sites. Susceptibility of An. arabiensis to fenitrothion, pirimiphosmethyl and propoxur was 100% in both study villages for three successive years. Resistance to bendiocarb was suspected after two years (2015) in Andassa, but not in Tikurit. Mortality and knock down due to DDT significantly increased from 2013 to 2015 at Tikurit (knock down: χ2 = 117.9, P<.0001 and mortality: χ2 = 66.3, P<.0001; due to deltamethrin, knock down: χ2 = 7.3, P=.004 and mortality: χ2 = 37.8, P<.0001). The same was true at Andassa (due to DDT, knock down: χ2 = 198.7, P<.0001 and mortality: χ2 = 82.9, P<.0001; due to deltamethrin, knock down: χ2 = 26.1, P<.0001 and mortality: χ2 = 48.2, P<.0001). Bendiocarb was effective against the An. arabiensis for two years under bendiocarb IRS operation so that alternative insecticides with different mode of action should be replaced every two to three years to prolong its efficacy.

Composition of mosquito fauna and insecticide resistance status of Anopheles gambiae sensu lato in Itang special district, Gambella, Southwestern Ethiopia

“…arabiensis populations in some other parts of Ethiopia [ 17 , 20 ]. The current result is similar to previously reported studies from different parts of Ethiopia [ 11 , 66 , 67 ] and Sudan [ 59 ] where propoxur fully killed An. gambiae s.l.…”

Diagnostic performance of PfHRP2/pLDH malaria rapid diagnostic tests in elimination setting, northwest Ethiopia

“…Malaria transmission is seasonal and unstable in the study area. Anopheles gambiae complex is the dominant species of mosquitoes that transmit malaria and Plasmodium falciparum and Plasmodium vivax are the two dominant parasite species in the study area [ 18 , 19 ]. According to the district health office report, the health center and its six satellite health posts serve an estimated 60,490 population.…”

Insecticide susceptibility status in two medically important mosquito vectors, Anopheles gambiae, and Culex quinquefasciatus to three insecticides commonly used in Niger State, Nigeria

“…An insecticide product's failure to achieve the required level of control when used as directed for a specific species at a specific time and place can result in pesticide resistance in mosquitoes, which is a natural and heritable trait in a species population. The volume and rate of pesticide applications against an insect population, as well as the inherent traits of the insect species involved, all influence the degree of resistance development ( Pates and Curtis, 2005 , Brooke and Koekemoer, 2010 , Abate et al, 2020 ).…”