Genetic Diversity of Cytochrome P450s and Associated with Pyrethroid Resistance in the Major Malaria Vectors and from Yaoundé, Cameroon.

Assessing the genetic diversity of metabolic resistance genes, such as cytochrome P450s, helps to understand the dynamics and evolution of resistance in the field. Here, we analyzed the polymorphisms of and associated with pyrethroid resistance in and , to detect potential resistance markers. Field-caught resistant mosquitos and susceptible lab strains were crossed, and F4 was exposed to permethrin for 15 min and 90 min to discriminate highly susceptible (HS) and highly resistant (HR) mosquitos, respectively.

Myxobolus makombensis n. sp. infection in African carp Labeobarbus batesii from the Makombè River, Cameroon: morphological and molecular characterization.

In this study, we examined myxozoan infections of Labeobarbus batesii sampled from the Makombè River in Cameroon. Fish were infected with Myxobolus makombensis n. sp.

Morphological and Molecular Characterization of Myxobolus nkondjockei sp. nov. (Myxozoa: Myxobolidae), A Parasite of Labeo batesii Boulenger, 1911 (Teleostei: Cyprinidae) from Makombè River in Cameroon.

Purpose: Myxozoans are economically important group of metazoan parasites, which can cause diseases in a large variety of commercially important fishes. Increased knowledge on molecular features has shown that traditional descriptive characters may be misleading. Combination of both descriptive and molecular features is therefore necessary for an integrated taxonomic assessment.

Multi-omics analysis identifies a CYP9K1 haplotype conferring pyrethroid resistance in the malaria vector Anopheles funestus in East Africa.

Metabolic resistance to pyrethroids is a menace to the continued effectiveness of malaria vector controls. Its molecular basis is complex and varies geographically across Africa. Here, we used a multi-omics approach, followed-up with functional validation to show that a directionally selected haplotype of a cytochrome P450, CYP9K1 is a major driver of resistance in Anopheles funestus.

Temporal variation of high-level pyrethroid resistance in the major malaria vector Anopheles gambiae s.l. in Yaoundé, Cameroon, is mediated by target-site and metabolic resistance.

Constant assessment of insecticide resistance levels is mandatory to implement adequate malaria control tools, but little information is available on the annual dynamics of resistance. We, therefore, monitored variations in resistance in Anopheles gambiae s.l.

Distribution of acetylcholinesterase (Ace-1) target-site G119S mutation and resistance to carbamates and organophosphates in Anopheles gambiae sensu lato populations from Cameroon.

Background: Cameroon is considering the implementation of indoor residual spraying (IRS) as a complementary measure to control malaria in the context of high pyrethroid resistance in major malaria vectors. Non-pyrethroid insecticide classes such as organophosphates and carbamates may be utilized in IRS due to widespread pyrethroid resistance. However, the success of this strategy depends on good knowledge of the resistance status of malaria vectors to carbamates and organophosphates.

Ecological plasticity to ions concentration determines genetic response and dominance of Anopheles coluzzii larvae in urban coastal habitats of Central Africa.

In Central Africa, the malaria vector Anopheles coluzzii is predominant in urban and coastal habitats. However, little is known about the environmental factors that may be involved in this process. Here, we performed an analysis of 28 physicochemical characteristics of 59 breeding sites across 5 urban and rural sites in coastal areas of Central Africa.

The G119S Acetylcholinesterase () Target Site Mutation Confers Carbamate Resistance in the Major Malaria Vector from Cameroon: A Challenge for the Coming IRS Implementation.

Growing resistance is reported to carbamate insecticides in malaria vectors in Cameroon. However, the contribution of acetylcholinesterase () to this resistance remains uncharacterised. Here, we established that the mutation is driving resistance to carbamates in populations from Cameroon.

Investigation of the influence of a glutathione S-transferase metabolic resistance to pyrethroids/DDT on mating competitiveness in males of the African malaria vector, .

Metabolic resistance is a serious challenge to current insecticide-based interventions. The extent to which it affects natural populations of mosquitoes including their reproduction ability remains uncharacterised. Here, we investigated the potential impact of the glutathione S-transferase L119F-GSTe2 resistance on the mating competitiveness of male , in Cameroon.

Overexpression of Two Members of D7 Salivary Genes Family is Associated with Pyrethroid Resistance in the Malaria Vector s.s. but Not in in Cameroon.

family proteins are among the most expressed salivary proteins in mosquitoes. They facilitate blood meal intake of the mosquito by scavenging host amines that induce vasoconstriction, platelet aggregation and pain. Despite this important role, little information is available on the impact of insecticide resistance on the regulation of proteins and consequently on the blood feeding success.

Dissecting functional components of reproductive isolation among closely related sympatric species of the complex.

Explaining how and why reproductive isolation evolves and determining which forms of reproductive isolation have the largest impact on the process of population divergence are major goals in the study of speciation. By studying recent adaptive radiations in incompletely isolated taxa, it is possible to identify barriers involved at early divergence before other confounding barriers emerge after speciation is complete. Sibling species of the complex offer opportunities to provide insights into speciation mechanisms.

Habitat segregation and ecological character displacement in cryptic African malaria mosquitoes.

Understanding how divergent selection generates adaptive phenotypic and population diversification provides a mechanistic explanation of speciation in recently separated species pairs. Towards this goal, we sought ecological gradients of divergence between the cryptic malaria vectors Anopheles coluzzii and An. gambiae and then looked for a physiological trait that may underlie such divergence.

Rapid evolution of pyrethroid resistance prevalence in Anopheles gambiae populations from the cities of Douala and Yaoundé (Cameroon).

Background: The adaptation of malaria vectors to urban areas is becoming a serious challenge for malaria control. The study presents the evolution of pyrethroid resistance in mosquito populations from the cities of Douala and Yaoundé between 2010 and 2013.

Methods: Susceptibility tests to permethrin and deltamethrin were carried out with two- to four-day old unfed Anopheles gambiae sensu lato adults raised from larvae collected from the field.

Exposure to disinfectants (soap or hydrogen peroxide) increases tolerance to permethrin in Anopheles gambiae populations from the city of Yaoundé, Cameroon.

Background: The rapid expansion of insecticide resistance is limiting the efficiency of malaria vector control interventions. However, current knowledge of factors inducing pyrethroid resistance remains incomplete. In the present study, the role of selection at the larval stage by disinfectants, such as soap and hydrogen peroxide (H2O2), on adult mosquito resistance to permethrin was investigated.

Physiological correlates of ecological divergence along an urbanization gradient: differential tolerance to ammonia among molecular forms of the malaria mosquito Anopheles gambiae.

Background: Limitations in the ability of organisms to tolerate environmental stressors affect their fundamental ecological niche and constrain their distribution to specific habitats. Evolution of tolerance, therefore, can engender ecological niche dynamics. Forest populations of the afro-tropical malaria mosquito Anopheles gambiae have been shown to adapt to historically unsuitable larval habitats polluted with decaying organic matter that are found in densely populated urban agglomerates of Cameroon.

High mosquito burden and malaria transmission in a district of the city of Douala, Cameroon.

Background: Rapid demographic growth in Douala city, Cameroon, has resulted in profound ecological and environmental changes. Although demographic changes can affect anopheline mosquito breeding sites, there is a lack of understanding about the epidemiological impact that such changes might have on vector ecology and malaria transmission.

Methods: A 12-month entomological study was conducted in a highly populated district of Douala called Ndogpassi.

Anthropogenic habitat disturbance and ecological divergence between incipient species of the malaria mosquito Anopheles gambiae.

Background: Anthropogenic habitat disturbance is a prime cause in the current trend of the Earth's reduction in biodiversity. Here we show that the human footprint on the Central African rainforest, which is resulting in deforestation and growth of densely populated urban agglomerates, is associated to ecological divergence and cryptic speciation leading to adaptive radiation within the major malaria mosquito Anopheles gambiae.

Methodology/principal Findings: In southern Cameroon, the frequency of two molecular forms--M and S--among which reproductive isolation is strong but still incomplete, was correlated to an index of urbanisation extracted from remotely sensed data, expressed as the proportion of built-up surface in each sampling unit.

Water Quality and Anopheles gambiae Larval Tolerance to Pyrethroids in the Cities of Douala and Yaoundé (Cameroon).

The poor management of the urban environment in sub-Saharan Africa is affecting Anopheles gambiae susceptibility to insecticides. A study was undertaken to assess the influence of breeding sites physicochemical parameters on malaria vectors population tolerance to insecticides. A total of 18, 262 larvae collected from 104 breeding sites were exposed to diagnostic concentrations of permethrin and deltamethrin.

Anopheles gambiae distribution and insecticide resistance in the cities of Douala and Yaoundé (Cameroon): influence of urban agriculture and pollution.

Background: Urban malaria is becoming a major health priority across Africa. A study was undertaken to assess the importance of urban pollution and agriculture practice on the distribution and susceptibility to insecticide of malaria vectors in the two main cities in Cameroon.

Methods: Anopheline larval breeding sites were surveyed and water samples analysed monthly from October 2009 to December 2010.

Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon.

Background: Highland areas of Africa are mostly malaria hypoendemic, due to climate which is not appropriate for anophelines development and their reproductive fitness. In view of designing a malaria control strategy in Western Cameroon highlands, baseline data on anopheline species bionomics were collected.

Methods: Longitudinal entomological surveys were conducted in three localities at different altitudinal levels.