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Anopheles gambiae

Assessing cross-resistance within the pyrethroids in terms of their interactions with key cytochrome P450 enzymes and resistance in vector populations

February 23, 2021 - 13:39 -- Open Access
Author(s): 
Moyes CL, Lees RS, Yunta C, Walker KJ, Hemmings K, Oladepo F, Hancock PA, Weetman D, Paine MJI, Ismail HM
Reference: 
Parasit Vectors. 2021 Feb 18;14(1):115

It is important to understand whether the potential impact of pyrethroid resistance on malaria control can be mitigated by switching between different pyrethroids or whether cross-resistance within this insecticide class precludes this approach.

The fungus Leptosphaerulina persists in Anopheles gambiae and induces melanization

February 23, 2021 - 12:53 -- Open Access
Author(s): 
Nattoh G, Bargul JL, Magoma G, Mbaisi L, Butungi H, Mararo E, Teal E, Herren JK
Reference: 
PLoS One. 2021 Feb 22;16(2):e0246452

Anopheles mosquitoes are colonized by diverse microorganisms that may impact on host biology and vectorial capacity. Eukaryotic symbionts such as fungi have been isolated from Anopheles, but whether they are stably associated with mosquitoes and transmitted transstadially across mosquito life stages or to subsequent generations remains largely unexplored.

NOT Open Access | The genetic architecture of target-site resistance to pyrethroid insecticides in the African malaria vectors Anopheles gambiae and Anopheles coluzzii

February 16, 2021 - 15:46 -- NOT Open Access
Author(s): 
Clarkson CS, Miles A, Harding NJ, O'Reilly AO, Weetman D, Kwiatkowski D, Donnelly MJ
Reference: 
Mol Ecol. 2021 Feb 16

Resistance to pyrethroid insecticides is a major concern for malaria vector control. Pyrethroids target the voltage-gated sodium channel (VGSC), an essential compo nent of the mosquito nervous system. Substitutions in the amino acid sequence can inducing a resistance phenotype. We use whole-genome sequence data from phase 2 of the Anopheles gambiae 1000 Genomes Project (Ag1000G) to provide a comprehensive account of genetic variation in the Vgsc gene across 13 African countries. In addition to known resistance alleles, we describe 20 other non-synonymous nucleotide substitutions at appreciable population frequency, and map these variants onto a protein model to investigate the likelihood of a pyrethroid resistance phenotypes.

A population genomic unveiling of a new cryptic mosquito taxon within the malaria-transmitting Anopheles gambiae complex

February 4, 2021 - 10:41 -- Open Access
Author(s): 
Tennessen JA, Ingham VA, Toé KH, Guelbéogo WM, Sagnon N, Kuzma R, Ranson H, Neafsey DE
Reference: 
Mol Ecol. 2021 Feb;30(3):775-790

The Anopheles gambiae complex consists of multiple morphologically indistinguishable mosquito species including the most important vectors of the malaria parasite Plasmodium falciparum in sub-Saharan Africa. Nine cryptic species have been described so far within the complex. The ecological, immunological and reproductive differences among these species will critically impact population responses to disease control strategies and environmental changes. Here, we examine whole-genome sequencing data from a longitudinal study of putative A. coluzzii in western Burkina Faso. Surprisingly, many specimens are genetically divergent from A. coluzzii and all other Anopheles species and represent a new taxon, here designated Anopheles TENGRELA (AT).

Synergism between nonane and emanations from soil as cues in oviposition‐site selection of natural populations of Anopheles gambiae and Culex quinquefasciatus

January 21, 2021 - 15:48 -- Open Access
Author(s): 
Victor S. Mwingira, Leonard E. G. Mboera and Willem Takken
Reference: 
Malaria Journal 2021 20:52, 21 January 2021

Olfactory cues have been shown to have an important role in guiding gravid mosquito females to selected sites for egg laying. The objective of this study was to determine the influence of emanations from soil from a breeding site and the putative oviposition pheromone nonane on oviposition-site selection of natural populations of Anopheles gambiae sensu lato (s.l.) and Culex quinquefasciatus.

Multiple blood feeding in mosquitoes shortens the Plasmodium falciparum incubation period and increases malaria transmission potential

January 7, 2021 - 09:02 -- Open Access
Author(s): 
Shaw WR, Holmdahl IE, Itoe MA, Werling K, Marquette M, Paton DG, Singh N, Buckee CO, Childs LM, Catteruccia F
Reference: 
PLoS Pathog. 2020 Dec 31;16(12):e1009131

Many mosquito species, including the major malaria vector Anopheles gambiae, naturally undergo multiple reproductive cycles of blood feeding, egg development and egg laying in their lifespan. Such complex mosquito behavior is regularly overlooked when mosquitoes are experimentally infected with malaria parasites, limiting our ability to accurately describe potential effects on transmission.

Insights into factors sustaining persistence of high malaria transmission in forested areas of sub-Saharan Africa: the case of Mvoua, South Cameroon

January 5, 2021 - 15:15 -- Open Access
Author(s): 
Mieguim Ngninpogni D, Ndo C, Ntonga Akono P, Nguemo A, Nguepi A, Metitsi DR, Tombi J, Awono-Ambene P, Bilong Bilong CF
Reference: 
Parasit Vectors. 2021 Jan 2;14(1):2

In Mvoua, a village situated in a forested area of Cameroon, recent studies have reported high prevalence of Plasmodium falciparum infection among the population. In order to understand factors that can sustain such a high malaria transmission, we investigated the biology of Anopheles vectors and its susceptibility to insecticides, as well as long-lasting insecticidal net (LLIN) coverage, use and bio-efficacy.

Delimiting cryptic morphological variation among human malaria vector species using convolutional neural networks

December 23, 2020 - 09:33 -- Open Access
Author(s): 
Couret J, Moreira DC, Bernier D, Loberti AM, Dotson EM, Alvarez M
Reference: 
PLoS Negl Trop Dis. 2020 Dec 17;14(12):e0008904

Deep learning is a powerful approach for distinguishing classes of images, and there is a growing interest in applying these methods to delimit species, particularly in the identification of mosquito vectors. Visual identification of mosquito species is the foundation of mosquito-borne disease surveillance and management, but can be hindered by cryptic morphological variation in mosquito vector species complexes such as the malaria-transmitting Anopheles gambiae complex. We sought to apply Convolutional Neural Networks (CNNs) to images of mosquitoes as a proof-of-concept to determine the feasibility of automatic classification of mosquito sex, genus, species, and strains using whole-body, 2D images of mosquitoes.

Mating-regulated atrial proteases control reinsemination rates in Anopheles gambiae females

December 16, 2020 - 10:58 -- Open Access
Author(s): 
Bascuñán P, Gabrieli P, Mameli E, Catteruccia F
Reference: 
Sci Rep. 2020 Dec 15;10(1):21974

Anopheles gambiae mosquitoes are the most important vectors of human malaria. The reproductive success of these mosquitoes relies on a single copulation event after which the majority of females become permanently refractory to further mating. This refractory behavior is at least partially mediated by the male-synthetized steroid hormone 20-hydroxyecdysone (20E), which is packaged together with other seminal secretions into a gelatinous mating plug and transferred to the female atrium during mating.

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

December 15, 2020 - 16:06 -- Open Access
Author(s): 
Bernard L. Kouassi, Constant Edi, Emmanuel Tia, Lucien Y. Konan, Maurice A. Akré, Alphonsine A. Koffi, Allassane F. Ouattara, Antoine Mea Tanoh, Pascal Zinzindohoue, Blaise Kouadio, McKenzie Andre, Seth R. Irish, Jennifer Armistead, Dereje Dengela, Ndombour G. Cissé, Cecilia Flatley
Reference: 
Malaria Journal 2020 19:454, 9 December 2020

Pyrethroid-treated mosquito nets are currently the mainstay of vector control in Côte d’Ivoire. However, resistance to pyrethroids has been reported across the country, limiting options for insecticide resistance management due to the paucity of alternative insecticides. Two types of insecticide-treated nets (ITNs), ITNs with pyrethroids and the synergist piperonyl butoxide (PBO), and Interceptor®G2 nets, a net treated with a combination of chlorfenapyr and alpha-cypermethrin, are believed to help in the control of pyrethroid-resistant mosquitoes.

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