Article
Entomology
Victoria A. Ingham, Linda Grigoraki, Hilary Ranson
Summary: Pyrethroids are still the most important insecticides for controlling malaria mosquitoes. However, resistance to pyrethroids in the major African malaria vector Anopheles gambiae has greatly accelerated in the 21st century. This review summarizes the current understanding of the mechanisms underlying this resistance and the challenges in developing genetic markers for monitoring and managing insecticide resistance in malaria vectors.
ENTOMOLOGIA GENERALIS
(2023)
Article
Multidisciplinary Sciences
Seynabou Sougoufara, Hanna Yorkston-Dives, Nurul Masyirah Aklee, Adanan Che Rus, Jaal Zairi, Frederic Tripet
Summary: This study found that mosquitoes are able to associate the odor of pesticides with their detrimental effects and subsequently avoid pesticide contact. These findings highlight the importance of mosquito cognition as determinants of pesticide resistance in mosquito populations targeted by chemical control.
SCIENTIFIC REPORTS
(2022)
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
Parasitology
Nadege Sonhafouo-Chiana, Leslie Diane Nkahe, Edmond Kopya, Parfait Herman Awono-Ambene, Samuel Wanji, Charles Sinclair Wondji, Christophe Antonio-Nkondjio
Summary: This study assessed the evolution of insecticide resistance and patterns of pesticide usage in agriculture in Yaounde, Cameroon. The results showed high resistance intensity to pyrethroids and uncontrolled usage of pesticides by farmers. It concluded that there is an urgent need to improve the management of insecticide resistance.
PARASITES & VECTORS
(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
Infectious Diseases
Casimir Dossou Kpanou, Hermann W. Sagbohan, Fortune Dagnon, Germain G. Padonou, Razaki Osse, Albert Sourou Salako, Aboubakar Sidick, Wilfried Sewade, Andre Sominahouin, Patrick Condo, Saadani Hassani Ahmed, Daniel Impoinvil, Martin Akogbeto
Summary: The study revealed resistance to pyrethroids in Anopheles gambiae in Parakou, Kandi, and Malanville in Benin, posing a potential threat to malaria vector control.
Article
Multidisciplinary Sciences
Corine Ngufor, Renaud Govoetchan, Augustin Fongnikin, Corneille Hueha, Juniace Ahoga, Thomas Syme, Abel Agbevo, Abdoulaye Daleb, Graham Small, Derric Nimmo, John Bradley, Rock Aikpon, Laurent Iyikirenga, Razaki Osse, Filemon Tokponnon, Germain Gil Padonou
Summary: VECTRON (TM) T500 was found to be non-inferior to Fludora (R) Fusion in controlling pyrethroid-resistant malaria vectors in central Benin. The insecticide showed prolonged residual efficacy on house walls and had high acceptability among homeowners. This community application provides improved and prolonged control of pyrethroid-resistant vectors and enhances our capacity to manage insecticide resistance.
SCIENTIFIC REPORTS
(2023)
Article
Infectious Diseases
Bedjou P. N'Dri, Nadja C. Wipf, Jasmina Saric, Behi K. Fodjo, Giovanna Raso, Juerg Utzinger, Pie Mueller, Chouaibou S. Mouhamadou
Summary: This study investigated the species composition, insecticide susceptibility status, and resistance mechanisms of malaria vectors in southern Cote d'Ivoire. The results showed the presence of different mosquito species, including the first documented finding of Anopheles arabiensis in Cote d'Ivoire. Genetic testing revealed mutations in resistance-related genes. The findings suggest the use of non-pyrethroid insecticides for indoor residual spraying and the consideration of additional measures to control outdoor biting by Anopheles arabiensis.
Article
Microbiology
Jsiane Etang, Stanislas Elysee Mandeng, Philippe Nwane, Herman Parfait Awono-Ambene, Jude D. Bigoga, Wolfgang Eyisap Ekoko, Achille Jerome Binyang, Michael Piameu, Lili Ranaise Mbakop, Narcisse Mvondo, Raymond Tabue, Remy Mimpfoundi, Jean Claude Toto, Immo Kleinschmidt, Tessa Bellamy Knox, Abraham Peter Mnzava, Martin James Donnelly, Etienne Fondjo
Summary: Understanding the evolution of insecticide resistance mechanisms in Anopheles gambiae mosquitoes in North Cameroon is crucial. This study found that metabolic resistance increased in one area but decreased in others, while the frequency of Kdr L995F alleles varied across different regions. These findings reveal the evolutionary trends of deltamethrin resistance mechanisms and suggest the need for non-pyrethroid vector control tools to supplement long-lasting insecticidal nets in North Cameroon.
Article
Infectious Diseases
Aziz Bouraima, Armel Djenontin, Yannelle Dossou, Lenucthadius Houessou, Christophe Soares, Montchede Anato, Boris-Enock Zinsou, Celia Dechavanne, Jerome Clain, Achille Massougbodji, Gilles Cottrell
Summary: The objective of this study was to estimate malaria transmission and insecticide resistance status in malaria vectors in Adjrako village from Ze District in Southern Benin. Human landing collections (HLCs) were performed to collect mosquitoes in the village. The study showed that An. gambiae s.l. is the main malaria vector in the area and it is resistant to deltamethrin and possibly bendiocarb.
Article
Infectious Diseases
Joyce K. Osoro, Maxwell G. Machani, Eric Ochomo, Christine Wanjala, Elizabeth Omukunda, Stephen Munga, Andrew K. Githeko, Guiyun Yan, Yaw A. Afrane
Summary: The study demonstrated that pyrethroid resistance in An. gambiae resulted in a fitness cost on their pre-imaginal development time and survival. Insecticide resistance delayed the development and reduced the survivorship of An. gambiae larvae, which is crucial in shaping resistant management strategies.
Article
Immunology
Jianhai Yin, Frederick Yamba, Canjun Zheng, Shuisen Zhou, Samuel Juana Smith, Lili Wang, Hongmei Li, Zhigui Xia, Ning Xiao
Summary: Multiple mutations involved in insecticide resistance in An. gambiae populations in Sierra Leone were detected in the kdrW, A296G rdl, and ace-1 alleles in the present study. It is necessary to monitor vector susceptibility levels to insecticides used in this country and update the insecticide resistance monitoring and management strategy.
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Edmund J. Norris, Jeffrey R. Bloomquist
Summary: This study explored the potential of two sodium channel activators, veratrine and aconitine, as insecticides and synergists of natural pyrethrins on Aedes aegypti. Aconitine was more toxic than veratrine and showed significant resistance in the pyrethroid-resistant strain. When applied in mixtures with piperonyl butoxide and pyrethrins, large synergism values were observed, particularly with aconitine on the pyrethroid-susceptible strain. The alkaloids also demonstrated synergistic effects when applied directly to the mosquito larval nervous system.
PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
(2022)
Article
Chemistry, Medicinal
Andreu Vidal-Albalat, Tomas Kindahl, Rajeshwari Rajeshwari, Cecilia Lindgren, Nina Forsgren, Stanley Kitur, Laura Sela Tengo, Fredrik Ekstrom, Luna Kamau, Anna Linusson
Summary: Insecticide resistance poses a threat to the prevention of infectious diseases by controlling disease-transmitting mosquitoes. New insecticidal compounds with minimal adverse effects on humans and the environment are urgently required. In this study, we investigate noncovalent inhibitors of acetylcholinesterase (AChE), a well-established target for insecticides, and find that certain compounds based on a 4-thiazolidinone scaffold effectively inhibit AChE from Anopheles gambiae and Aedes aegypti mosquitoes. The selectivity of these compounds depends on the substitution pattern of the phenyl ring.
JOURNAL OF MEDICINAL CHEMISTRY
(2023)
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
Biology
Penelope A. Hancock, Amy Lynd, Antoinette Wiebe, Maria Devine, John Essandoh, Francis Wat'senga, Emile Z. Manzambi, Fiacre Agossa, Martin J. Donnelly, David Weetman, Catherine L. Moyes
Summary: This study developed a statistical spatiotemporal model to investigate target-site resistance in malaria vectors in Africa. The results showed variations in the spread dynamics of resistance mutations across different vector species and geographic regions. The coverage of insecticide-treated bed nets was found to have varying effects on allele frequencies in different species and regions.
Article
Parasitology
Christopher M. Owusu-Asenso, Julius A. A. Mingle, David Weetman, Yaw A. Afrane
Summary: This study investigated the spatiotemporal distribution and insecticide resistance status of Aedes aegypti across different ecological zones in Ghana. The results showed that Aedes mosquitoes were found at high densities in all areas and exhibited resistance to certain insecticides. These findings are important for the development of effective vector control programs.
PARASITES & VECTORS
(2022)
Article
Multidisciplinary Sciences
Johnson Matowo, David Weetman, Patricia Pignatelli, Alexandra Wright, Jacques D. Charlwood, Robert Kaaya, Boniface Shirima, Oliva Moshi, Eliud Lukole, Jacklin Mosha, Alphaxard Manjurano, Franklin Mosha, Mark Rowland, Natacha Protopopoff
Summary: In Africa, the efficacy of long lasting insecticidal nets (LLINs) in reducing malaria transmission is being reduced by pyrethroid resistance in the major vectors. A study found that pre-exposure to piperonyl butoxide (PBO) followed by permethrin exposure partially restored susceptibility in mosquitoes. The study also identified multiple over expressed P450 genes in pyrethroid-resistant mosquitoes.
Article
Entomology
Rosemary S. Lees, Jennifer S. Armistead, Salum Azizi, Edi Constant, Christen Fornadel, John E. Gimnig, Janet Hemingway, Daniel Impoinvil, Seth R. Irish, William Kisinza, Natalie Lissenden, Henry D. Mawejje, Louisa A. Messenger, Sarah Moore, Corine Ngufor, Richard Oxborough, Natacha Protopopoff, Hilary Ranson, Graham Small, Joseph Wagman, David Weetman, Sarah Zohdy, Angus Spiers
Summary: To test the effectiveness and durability of new bed nets, it is necessary to study and test insecticide-resistant mosquitoes. A group of experts collaborated to develop a protocol for standardized monitoring and accurate characterization of resistant mosquitoes, providing valuable guidance for malaria control programs and stakeholders.
Article
Biochemistry & Molecular Biology
Harun Njoroge, Arjen van't Hof, Ambrose Oruni, Dimitra Pipini, Sanjay C. Nagi, Amy Lynd, Eric R. Lucas, Sean Tomlinson, Xavi Grau-Bove, Daniel McDermott, Francis T. Wat'senga, Emile Z. Manzambi, Fiacre R. Agossa, Arlette Mokuba, Seth Irish, Bilali Kabula, Charles Mbogo, Joel Bargul, Mark J. Paine, David Weetman, Martin J. Donnelly
Summary: Studies on insecticide resistance provide insights into the rapid evolutionary response of populations to contemporary selection. This study identified twin mutations and a triple-mutant haplotype that can predict mosquito resistance to pyrethroid insecticides, and found that the use of synergists in long lasting insecticidal nets can increase mortality in mosquitoes carrying the triple-mutant haplotype.
Article
Infectious Diseases
Athanase Badolo, Aboubacar Sombie, Felix Yameogo, Dimitri W. Wangrawa, Aboubakar Sanon, Patricia M. Pignatelli, Antoine Sanon, Mafalda Viana, Hirotaka Kanuka, David Weetman, Philip J. Mccall
Summary: The emergence of dengue in West Africa, particularly the outbreaks in Burkina Faso in 2016 and 2017, has led to surveys of Aedes populations in the capital city of Ouagadougou. The results show that the abundance of adult Ae. aegypti is significantly higher in urban areas compared to the rural site, which has a higher population of Anopheles spp. The vector population is highly anthropophilic and exhibits a high proportion of bloodfed females caught inside houses. The primary larval habitats are waste tires, animal troughs, and large water barrels. Factors influencing adult and immature stage densities include rainfall, container water level, collection month, and container type/purpose.
PLOS NEGLECTED TROPICAL DISEASES
(2022)
Article
Infectious Diseases
Richard Allan, David Weetman, Hendrik Sauskojus, Sophie Budge, Tarek Bin Hawail, Yasser Baheshm
Summary: The presence of An. stephensi, a malaria vector, in urban communities hosting internally displaced people (IDPs) in Yemen is confirmed. Proactive monitoring and targeted management strategies are needed to control malaria transmission and prevent further spread of the vector.
Article
Evolutionary Biology
Neil Philip Hobbs, David Weetman, Ian Michael Hastings
Summary: Controlling malaria involves using insecticides to kill mosquitoes, but increasing levels of insecticide resistance (IR) pose a threat to recent successes in malaria control. To mitigate this problem, insecticide resistance management (IRM) strategies are employed. Field trials of IRM strategies are costly and time-consuming, so mathematical modeling is often used to evaluate alternative options. Previous models assumed a simple genetic basis for IR, but in natural populations, IR is often a complex polygenic trait. A quantitative genetics model was developed to simulate IR as a polygenic trait and evaluate different IRM strategies. The results showed that deploying two insecticides in a full-dose mixture formulation extended the strategy lifespan, regardless of the level of cross resistance or starting level of resistance. This study highlights the importance of insecticide coverage, cross resistance, heritability, and fitness costs in selecting an appropriate IRM strategy.
EVOLUTIONARY APPLICATIONS
(2023)
Article
Entomology
Ousmane Sy, Pape C. Sarr, Benoit S. Assogba, Mouhamed A. Nourdine, Assane Ndiaye, Lassana Konate, Ousmane Faye, Martin J. Donnelly, Oumar Gaye, David Weetman, Elhadji A. Niang
Summary: Understanding the behavior and ecology of local malaria vectors is crucial for effective malaria control strategies in low transmission areas. This study in central Senegal identified An. arabiensis and An. melas as the major malaria vectors responsible for transmitting Plasmodium falciparum. Targeting both vectors is necessary for malaria elimination efforts in this region.
JOURNAL OF MEDICAL ENTOMOLOGY
(2023)
Article
Parasitology
Aboubacar Sombie, Wendegoudi Mathias Ouedraogo, Manabu Ote, Erisha Saiki, Tatsuya Sakurai, Felix Yameogo, Antoine Sanon, Philip J. McCall, Hirotaka Kanuka, David Weetman, Athanase Badolo
Summary: Since 2000, Burkina Faso has seen regular dengue cases and outbreaks, highlighting the increasing importance of dengue as a health concern in the country. Resistance to pyrethroid insecticides in Aedes aegypti mosquitoes has been linked to specific kdr mutations. This study confirms high resistance to pyrethroids in the Ae. aegypti populations and proposes a new PCR-based diagnostic method for detecting kdr mutations.
PARASITES & VECTORS
(2023)
Article
Parasitology
Anisa Abdulai, Christopher Mfum Owusu-Asenso, Gabriel Akosah-Brempong, Abdul Rahim Mohammed, Isaac Kwame Sraku, Simon Kwaku Attah, Akua Obeng Forson, David Weetman, Yaw Asare Afrane
Summary: Outbreaks of Aedes-borne arboviral diseases are increasing in Africa, and Ghana lacks an organized arboviral control program. This study assessed the insecticide resistance status of Aedes aegypti populations in southern and northern Ghana. The findings indicate the need for surveillance and appropriate vector control strategies for arboviral disease control in Ghana.
PARASITES & VECTORS
(2023)
Article
Multidisciplinary Sciences
Walter Fabricio Silva Martins, Emma Reid, Sean Tomlinson, George Evans, Jennie Gibson, Amy Guy, Martin Donnelly, David Weetman
Summary: Developing robust and standardised approaches for testing mosquito populations against insecticides is crucial. While well-established methods exist for testing contact insecticides or products, challenges remain for testing volatile or aerosolized insecticides used in household products. In this study, we adapted WHO guidelines to develop a standardised and higher-throughput methodology for testing aerosolized products in a Peet Grady test chamber. The new approach was validated using insecticide resistant and susceptible mosquito colonies.
SCIENTIFIC REPORTS
(2023)
Article
Public, Environmental & Occupational Health
Adande A. Medjigbodo, Laurette Djossou, Constantin J. Adoha, Oswald Y. Djihinto, Aurore Ogouyemi-Hounto, Martin J. Donnelly, David Weetman, Luc S. Djogbenou
Summary: Understanding the role of asymptomatic Plasmodium carriers in malaria transmission is important for developing effective control measures. This study examined the prevalence of asymptomatic and symptomatic Plasmodium infections and their contribution to malaria transmission in Ouidah, Benin. The results showed that asymptomatic carriers can significantly contribute to the transmission of malaria.
PARASITE EPIDEMIOLOGY AND CONTROL
(2023)
Article
Parasitology
Henry Ddumba Mawejje, David Weetman, Adrienne Epstein, Amy Lynd, Jimmy Opigo, Catherine Maiteki-Sebuguzi, Jo Lines, Moses R. Kamya, Philip J. Rosenthal, Martin J. Donnelly, Grant Dorsey, Sarah G. Staedke
Summary: Insecticide resistance is a major threat to malaria control in Africa. A study in Uganda found that both Anopheles gambiae and Anopheles arabiensis have developed resistance to pyrethroids. The study also demonstrated that adding piperonyl butoxide can increase the mortality rate of these mosquitoes.
CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES
(2023)
Article
Parasitology
Ashwaq M. Al Nazawi, David Weetman
Summary: Monitoring insecticide resistance is crucial for evaluating effective insecticides for control and understanding resistance changes. Testing young mosquitoes for susceptibility can capture the minimum response of the population, but older females may exhibit lower susceptibility to pyrethroid-based control measures due to repeated exposure.
CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES
(2023)