Impact of Urban Agriculture on the Species Distribution and Insecticide Resistance Profile of <i>Anopheles gambiae s.s.</i> and <i>Anopheles coluzzii</i> in Accra Metropolis, Ghana

Abstract

Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that promote urban malaria to help formulate future vector control strategies. This study compared Anopheles gambiae s.l. (A. gambiae s.l.) species composition, distribution and insecticide resistance mechanisms between vegetable and non-vegetable growing areas in Accra Metropolis. Four sites were selected within the city of Accra which comprised of two vegetable-growing and two non-vegetable growing areas. WHO susceptibility tests were carried out on adults A. gambiae s.l. reared from larvae collected from the sites. Five insecticides were tested and the A. gambiae complex, resistance genotypes and enzyme activities of each population were characterized. All A. gambiae s.l. populations tested were resistant to all the insecticides, but relatively lower mortalities were observed in the vegetable growing areas. The mortality against 0.05% deltamethrin was 2.6% (Opeibea) and 12.5% (Korle-Bu) for the vegetaHow to cite this paper: Chabi J., Eziefule, M.C., Pwalia, R., Joannides, J., Obuobi, D., Amlalo, G., Addae, C.A., Alidu, I., Acquah-Baidoo, D., Akporh, S., Gbagba, S., Frempong, K.K., Hadi, M.P., Jamet, H.P.

High insecticide resistance intensity of Anopheles gambiae (s.l.) and low efficacy of pyrethroid LLINs in Accra, Ghana

“…from Opeibea with regards to the level of resistance recorded and the constant Vgsc mutation which is almost fixed within the colony. The high insecticide resistance of the mosquito population from Opeibea might have been sustained by the intense use of pesticides and insecticides by the farmers as previously described [33]. It is known that agricultural practices impact the resistance to insecticides of An.…”

“…The increased peak of mortality observed after the month of May could be explained by the fact that the rainy season in Accra during the period coincided with mosquito breeeding sites and subsequently increased the volume of water in which mosquito larvae were breeding. However, agricultural activities are practised in the area of Opeibea all year round with permanent use of pesticides [33]. The Greater Accra region where the site is located has two rainy seasons with the long season starting from May.…”

Phenotypic Characterization of the Resistance Status of Anopheles gambiae s.l. from Oyem, North Gabon to Four Classes of Insecticides

“…In addition, this strong resistance to DDT could also be explained by the repeated use of this insecticide during programs to protect cocoa and coffee crops against pests in the 1990s (Petithuguenin, 1994). Moreover, according to some authors, excessive usage of insecticides in agricultural and industrial areas (such as Oyem) favors the selection of resistant vector populations (Hien et al, 2017;Chabi et al, 2018). Additionally, in some countries, resistance to DDT and Pyrethroids emerged in 1967 in Burkina Faso and 1993 in Côte d'Ivoire respectively.…”

Susceptibility of Anopheles gambiae from Côte d’Ivoire to insecticides used on insecticide-treated nets: Evaluating the additional entomological impact of piperonyl butoxide and chlorfenapyr

“…A recent survey by the ministry of agriculture revealed that more than 20,000 tons of chemicals including pesticides and insecticides were applied in the country in 2018 for agricultural purposes including 40% of this amount entering illegally [38]. This likely contributed to the increasing resistance of malaria vectors to insecticides commonly used for insect control in general and malaria vector control speci cally [36,37,39]. In Côte d'Ivoire, the two major malaria vectors include An.…”

“…Both species generally breed in fresh water pools resulting from human activities such as irrigated rice elds and vegetable gardens, which are often treated with insecticides [36,37,39,41]. As described by Chouaibou et al [42], agricultural pesticides contain several insecticide molecules and particularly pyrethroids and carbamates, which contribute to the increased and widespread resistance of the vectors [39]. Furthermore, studies conducted in Western and Eastern Africa have shown a signi cant increase in the frequency of genes associated with pyrethroid resistance immediately following the implementation of an ITN campaign [7].…”