Article
Biochemistry & Molecular Biology
Amelie N. R. Wamba, Sulaiman S. Ibrahim, Michael O. Kusimo, Abdullahi Muhammad, Leon M. J. Mugenzi, Helen Irving, Murielle J. Wondji, Jack Hearn, Jude D. Bigoga, Charles S. Wondji
Summary: The study confirmed the overexpression of CYP325A in pyrethroid-resistant Anopheles funestus from Cameroon, leading to metabolic resistance to insecticides. High genetic polymorphism was observed, along with noticeable geographical amino acid changes. Analysis of the promoter region of CYP325A suggested a potential selective sweep in resistant mosquitoes.
INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY
(2021)
Article
Microbiology
Benjamin D. Menze, Leon M. J. Mugenzi, Magellan Tchouakui, Murielle J. Wondji, Micareme Tchoupo, Charles S. Wondji
Summary: Malaria remains a major public health concern in Africa. Metabolic resistance in major malaria vectors such as An. funestus is jeopardizing the effectiveness of long-lasting insecticidal nets (LLINs) to control malaria. Experimental hut trials revealed that cytochrome P450-based resistance significantly reduces the efficacy of permethrin-only nets compared to PBO-based nets. The findings highlight the importance of PBO nets in areas with P450-mediated resistance to pyrethroids.
Article
Biochemistry & Molecular Biology
Magellan Tchouakui, Leon M. J. Mugenzi, Murielle J. Wondji, Micareme Tchoupo, Flobert Njiokou, Charles S. Wondji
Summary: The study reveals that the over-expression of multiple P450 genes results in cumulative fitness costs for pyrethroid-resistant Anopheles funestus, impacting their reproductive capacity and development speed significantly. Additionally, in an insecticide-free environment, there is a potential increase in the proportion of susceptible individuals.
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Melanie Nolden, Robert Velten, Mark J. I. Paine, Ralf Nauen
Summary: Resistance to common pyrethroids, such as deltamethrin and permethrin, is widespread in the malaria mosquito Anopheles funestus due to upregulated cytochrome P450 monooxygenases. The duplicated genes CYP6P9a and CYP6P9b are highly upregulated in the pyrethroid resistant strain and have been shown to metabolize various pyrethroids. Although CYP6P9 variants interact with transfluthrin, their metabolic capacity to degrade transfluthrin is low, explaining the lack of resistance observed. Therefore, transfluthrin is an important resistance-breaking pyrethroid in controlling An. funestus.
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
(2023)
Article
Genetics & Heredity
Magellan Tchouakui, Leon M. J. Mugenzi, Murielle J. Wondji, Micareme Tchoupo, Flobert Njiokou, Charles S. Wondji
Summary: Understanding the fitness cost of metabolic resistance in malaria vectors is crucial for effective resistance management. This study shows that a structural variant in genes involved in insecticide resistance leads to reduced fecundity and slower development in resistant mosquitoes. Additionally, the cumulative impact of multiple resistance genes exacerbates these effects. However, in an insecticide-free environment, susceptible individuals have a higher proportion, leading to restoration of susceptibility.
Article
Microbiology
Fleuriane Metissa Djondji Kamga, Leon M. J. Mugenzi, Magellan Tchouakui, Maurice Marcel Sandeu, Claudine Grace Tatsinkou Maffo, Maximilienne Ascension Nyegue, Charles S. S. Wondji
Summary: This study investigates the association between a specific endosymbiont, Asaia spp., and pyrethroid resistance in malaria vectors. The presence of Asaia was found to be higher in mosquitoes with resistance markers, indicating a possible correlation. Furthermore, the abundance of Asaia was correlated with the resistance phenotype at different concentrations of deltamethrin.
Article
Biochemistry & Molecular Biology
Melanie Nolden, Mark J. Paine, Ralf Nauen
Summary: Cytochrome P450 monooxygenases play a crucial role in the oxidative metabolism of xenobiotics in insects and their duplication and upregulation can lead to insecticide resistance. The interaction between P450s and other enzymes like NADPH cytochrome P450 oxidoreductase and cytochrome b5 is complex and can impact metabolic capacity. Recombinant expression of P450s in insect cells with cytochrome b5 can significantly enhance their ability to metabolize certain substrates, but not necessarily insecticides like deltamethrin.
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Melanie Nolden, Mark J. I. Paine, Ralf Nauen
Summary: Pyrethroid resistance in Anopheles funestus is a major threat to the eradication of malaria. This study identified the enzymes CYP6P9a and CYP6P9b as major drivers of pyrethroid resistance in An. funestus, and investigated their interactions with azole-fungicides and pyrethroids. The study found that the mutation V310I in CYP6P9b increased its metabolic activity towards pyrethroids, particularly permethrin. Additionally, the study discovered the first metabolites of permethrin and deltamethrin, which were also suitable substrates for the CYP6P9 variants and were depleted to a higher extent than their parent compounds. Furthermore, it was confirmed that CYP6P9a and CYP6P9b are capable of metabolizing pyrethroids. These findings provide new insights into the molecular mechanisms of pyrethroid resistance in An. funestus.
INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY
(2022)
Article
Parasitology
Emilie S. Ngongang-Yipmo, Magellan Tchouakui, Benjamin D. Menze, Leon M. J. Mugenzi, Flobert Njiokou, Charles S. Wondji
Summary: This study investigated the efficacy of different brands of LLINs against pyrethroid-resistant mosquitoes and their post-exposure effect. The results showed that standard bednets had reduced efficacy against resistant mosquitoes in the field, but still induced delayed mortality in exposed populations. The study also highlighted the importance of using new-generation nets that do not solely rely on pyrethroids.
PARASITES & VECTORS
(2022)
Article
Genetics & Heredity
Arnaud Tepa, Jonas A. Kengne-Ouafo, Valdi S. Djova, Magellan Tchouakui, Leon M. J. Mugenzi, Rousseau Djouaka, Constant A. Pieme, Charles S. Wondji
Summary: The main malaria vector Anopheles gambiae in a pesticide-driven agricultural hotspot in Cameroon has developed resistance to multiple insecticides, leading to a loss in the efficacy of control interventions.
Article
Multidisciplinary Sciences
Helena Marti-Soler, Mara Maquina, Mercy Opiyo, Celso Alafo, Ellie Sherrard-Smith, Arlindo Malheia, Nelson Cuamba, Charfudin Sacoor, Regina Rabinovich, Pedro Aide, Francisco Saute, Krijn Paaijmans
Summary: The study assessed the residual efficacy of SumiShield((TM)) 50WG, a third generation IRS product introduced in southern Mozambique, and found that it did not meet the current WHO threshold value for effective IRS in both young and old mosquitoes. Therefore, considering delayed mortality, residual efficacies ranged from 1.5 to >= 12.5 months, depending on mortality time post exposure, wall type, and mosquito age.
Article
Infectious Diseases
Smita Das, Mara Maquina, Keeley Phillips, Nelson Cuamba, Dulcisaria Marrenjo, Francisco Saute, Krijn P. Paaijmans, Silvie Huijben
Summary: This study investigated the genetic diversity, population structure, and insecticide resistance profiles of mosquito populations. The results showed high levels of gene flow among mosquito populations and variation in insecticide resistance. These findings suggest that resistance markers may not capture all phenotypic variation, but high impact resistance genes are likely to spread easily in this area.
Article
Biotechnology & Applied Microbiology
V. A. Ingham, F. Brown, H. Ranson
Summary: Sub-lethal exposure to the pyrethroid deltamethrin results in significant and sustained changes to the transcriptome of the major malaria vector Anopheles coluzzii. This study highlights the importance of considering the effects of aging and diel cycle on insecticide resistance related transcripts, and the potential impact of transcriptional changes on key mosquito traits like vectorial capacity and life history traits.
Review
Microbiology
Oswald Y. Djihinto, Adande A. Medjigbodo, Albert R. A. Gangbadja, Helga M. Saizonou, Hamirath O. Lagnika, Dyane Nanmede, Laurette Djossou, Romeo Bohounton, Pierre Marie Sovegnon, Marie-Joel Fanou, Romuald Agonhossou, Romaric Akoton, Wassiyath Mousse, Luc S. Djogbenou
Summary: Malaria is a major public health concern worldwide, especially in tropical regions. The control strategies targeting mosquito vectors, such as the use of chemical insecticides, are being hindered by the spread of resistance among mosquito populations. Therefore, there is a need to develop novel and environmentally friendly tools to improve vector control, such as utilizing the microbiota of mosquitoes.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Microbiology
Magellan Tchouakui, Leon M. J. Mugenzi, Benjamin D. Menze, Jude N. T. Khaukha, Williams Tchapga, Micareme Tchoupo, Murielle J. Wondji, Charles S. Wondji
Summary: The study revealed high intensity of pyrethroid resistance in major malaria vectors in Uganda, leading to reduced effectiveness of insecticide-treated nets. The over-expression of cytochrome P450 genes may not be the only resistance mechanism involved in this case. Urgent action should be taken to prevent the spread of super-resistance in malaria vectors.
Article
Entomology
Muhammad M. Mukhtar, Sulaiman S. Ibrahim
Summary: Outbreaks of dengue and yellow fever are increasing in Nigeria, and controlling these arboviral diseases requires understanding of mosquito vectors and their insecticide resistance. This study characterized two populations of Aedes aegypti in Nigeria and found increasing resistance to insecticides, posing challenges for control measures.
Article
Biochemistry & Molecular Biology
Jack Hearn, Carlos S. Djoko Tagne, Sulaiman S. Ibrahim, Billy Tene-Fossog, Leon M. J. Mugenzi, Helen Irving, Jacob M. Riveron, Gareth D. Weedall, Charles S. Wondji
Summary: This study investigates the molecular basis of metabolic resistance to pyrethroids in Anopheles funestus, a major malaria vector. The researchers used a multi-omics approach and functional validation to identify a cytochrome P450, CYP9K1, as a major driver of resistance. The study also identified other genes and variants associated with resistance and suggests their potential use in designing field-applicable markers for tracking resistance in Africa-wide.
Article
Genetics & Heredity
Arnaud Tepa, Jonas A. Kengne-Ouafo, Valdi S. Djova, Magellan Tchouakui, Leon M. J. Mugenzi, Rousseau Djouaka, Constant A. Pieme, Charles S. Wondji
Summary: The main malaria vector Anopheles gambiae in a pesticide-driven agricultural hotspot in Cameroon has developed resistance to multiple insecticides, leading to a loss in the efficacy of control interventions.
Article
Environmental Sciences
Alvine Christelle Kengne Fokam, Laurentine Sumo, Mohamed Bagayan, Hugues Clotaire Nana-Djeunga, Thomas Kuete, Gabriella S. Ondoua Nganjou, Murielle Carole Tchami Mbagnia, Linda Djune-Yemeli, Charles Sinclair Wondji, Flobert Njiokou
Summary: This study assessed the toxicity of Niclosamide on different developmental stages of snail populations. The results showed that the susceptibility of snails varied among species and populations, and Niclosamide exhibited significant lethal effects on certain snail populations.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2022)
Article
Entomology
Borel Djiappi-Tchamen, Mariette Stella Nana-Ndjangwo, Elysee Nchoutpouen, Idene Makoudjou, Idriss Nasser Ngangue-Siewe, Abdou Talipouo, Marie Paul Audrey Mayi, Parfait Awono-Ambene, Charles Wondji, Timoleon Tchuinkam, Christophe Antonio-Nkondjio
Summary: The emergence/re-emergence of arboviruses diseases including dengue, chikungunya, and yellow fever is a serious public health concern in Cameroon. Vector surveillance, including the assessment of Aedes species distribution through different collection methods, is crucial for prevention strategies. A study was conducted in and around the city of Yaounde, Cameroon, using ovitraps, Biogent Sentinel traps, and sweep nets. Results revealed a high infestation level of Aedes species and emphasized the need for regular surveillance and control to prevent outbreaks.
Article
Genetics & Heredity
Yvan Fotso-Toguem, Billy Tene-Fossog, Leon M. J. Mugenzi, Murielle J. Wondji, Flobert Njiokou, Hilary Ranson, Charles S. Wondji
Summary: The polymorphisms of CYP6M2 and CYP6P4 were analyzed to detect potential resistance markers in Anopheles coluzzii and Anopheles gambiae. The study found significant overexpression of CYP6M2 and CYP6P4 in resistant mosquitos, and a lower diversity in the upstream region of CYP6P4 potentially associated with resistance.
Article
Entomology
Salomon Efa, Emmanuel Elanga-Ndille, Yacouba Poumachu, Billy Tene, Jacqueline Ze Mikande, Njoumemi Zakariaou, Charles S. Wondji, Cyrille Ndo
Summary: Monitoring insecticide resistance in major malaria vectors like Anopheles gambiae s.l. is crucial for designing effective vector control strategies and preventing the spread of resistance. This study in Ebolowa, Southern Cameroon, revealed high resistance to pyrethroid insecticides in Anopheles coluzzii, posing a risk to the efficacy of Long-Lasting Insecticidal Nets (LLINs) used for malaria control. Urgent implementation of resistance management strategies is needed to maintain the effectiveness of insecticide-based interventions.
Article
Biology
Sulaiman S. Ibrahim, Abdullahi Muhammad, Jack Hearn, Gareth D. Weedall, Sanjay C. Nagi, Muhammad M. Mukhtar, Amen N. Fadel, Leon J. Mugenzi, Edward I. Patterson, Helen Irving, Charles S. Wondji
Summary: Transcriptional analysis of Anopheles coluzzii populations from the Sahel region revealed overexpression of genes associated with insecticide resistance, including CYP450s, glutathione S-transferases, carboxylesterases, and cuticular proteins. High frequencies of known markers of resistance were also observed. These findings have important implications for malaria control efforts and regional collaboration.
Article
Genetics & Heredity
Leon M. J. Mugenzi, Theofelix A. Tekoh, Sulaiman S. Ibrahim, Abdullahi Muhammad, Mersimine Kouamo, Murielle J. Wondji, Helen Irving, Jack Hearn, Charles S. Wondji
Summary: Insecticide resistance in vector species populations is posing a threat to the effectiveness of insecticide-based interventions against malaria. This study identified the overexpression of certain metabolic cytochrome P450 genes in resistant Anopheles funestus populations, which confers resistance to both pyrethroid and carbamate insecticides. Understanding the molecular basis of insecticide resistance is crucial for the development of suitable interventions.
Article
Microbiology
Fleuriane Metissa Djondji Kamga, Leon M. J. Mugenzi, Magellan Tchouakui, Maurice Marcel Sandeu, Claudine Grace Tatsinkou Maffo, Maximilienne Ascension Nyegue, Charles S. S. Wondji
Summary: This study investigates the association between a specific endosymbiont, Asaia spp., and pyrethroid resistance in malaria vectors. The presence of Asaia was found to be higher in mosquitoes with resistance markers, indicating a possible correlation. Furthermore, the abundance of Asaia was correlated with the resistance phenotype at different concentrations of deltamethrin.
Article
Microbiology
Marcel Tapsou Baina, Abel Lissom, Naura Veil Assioro Doulamo, Jean Claude Djontu, Dieu Merci Umuhoza, Jacques Dollon Mbama-Ntabi, Steve Diafouka-Kietela, Jolivet Mayela, Georges Missontsa, Charles Wondji, Ayola Akim Adegnika, Etienne Nguimbi, Steffen Borrmann, Francine Ntoumi
Summary: This study compares the genetic diversity of Plasmodium falciparum strains in rural and urban areas of the Republic of Congo after the introduction of artemisinin-based combination therapy. The results show higher genetic diversity and multiplicity of infection in the rural setting, influenced by season and participant clinical status.
Article
Infectious Diseases
Tatiane Assatse, Magellan Tchouakui, Leon Mugenzi, Benjamin Menze, Daniel Nguiffo-Nguete, Williams Tchapga, Sevilor Kekeunou, Charles S. Wondji
Summary: The susceptibility of Anopheles funestus mosquitoes to neonicotinoids was evaluated across Africa, and diagnostic doses of acetamiprid and imidacloprid were established. The study revealed that populations of An. funestus in Africa are susceptible to neonicotinoids, indicating the potential for using this insecticide class to control malaria transmission. However, the presence of cross-resistance calls for regular monitoring of resistance in the field.
TROPICAL MEDICINE AND INFECTIOUS DISEASE
(2023)
Article
Entomology
Oumou Kalsom Gueye, Abdoulaye Niang, Mouhamed Bassir Faye, Abdoulaye Kane Dia, Amblat Ali Ahmed, Ousmane Sy, Frederic Tripet, Lassana Konate, Ibrahima Dia, Charles Sinclair Wondji, Oumar Gaye, Ousmane Faye, Abdoulaye Diabate, El Hadji Amadou Niang
Summary: In Senegal, there is a clear difference in the mating swarms of An. coluzzii and An. gambiae, the malaria vector species, with no hybridization observed. The study reveals that while they do not hybridize, they exhibit distinct swarming behaviors. However, a high hybridization rate is still found in the hybridization zones, indicating the need for further extensive studies.
JOURNAL OF MEDICAL ENTOMOLOGY
(2023)
Article
Microbiology
Francis N. Nkemngo, Lymen W. Raissa, Daniel N. Nguete, Cyrille Ndo, Jerome Fru-Cho, Flobert Njiokou, Samuel Wanji, Charles S. Wondji
Summary: Molecular surveillance of malaria is essential for detecting and tracking parasite resistance to anti-malarial drugs. This study conducted molecular techniques to determine the prevalence and genetic diversity of Plasmodium falciparum and Plasmodium malariae resistance markers in humans and mosquitoes in Cameroon. The results showed high prevalence of malaria and the emergence of drug-resistant alleles. The findings highlight the importance of continued surveillance and intervention strategies to prevent the spread of resistance.
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2023)