Long-lasting insecticidal nets no longer effectively kill the highly resistant Anopheles funestus of southern Mozambique
Autor: | Quique Bassat, Pedro L. Alonso, Ana Paula Abílio, Allison Gilbert, Helder Bulo, Katey D. Glunt, Eusebio Macete, Krijn P. Paaijmans, Maria N. Manaca, Silvie Huijben |
---|---|
Rok vydání: | 2015 |
Předmět: |
Insecticides
Mosquito Control Insecticide resistance LLINs Indoor residual spraying An. arabiensis Malària Bioassays Toxicology Anopheles funestus chemistry.chemical_compound Medicina preventiva Pyrethrins parasitic diseases Anopheles medicine Animals Humans Pyrethroids Insecticide-Treated Bednets Mozambique Preventive medicine biology business.industry Research medicine.disease biology.organism_classification Biotechnology Insect Vectors Malaria Mosquito control Infectious Diseases Deltamethrin chemistry Parasitology Malaria vectors Female business Permethrin medicine.drug |
Zdroj: | Dipòsit Digital de la UB Universidad de Barcelona Malaria Journal Recercat. Dipósit de la Recerca de Catalunya instname |
Popis: | BACKGROUND: Chemical insecticides are crucial to malaria control and elimination programmes. The frontline vector control interventions depend mainly on pyrethroids; all long-lasting insecticidal nets (LLINs) and more than 80% of indoor residual spraying (IRS) campaigns use chemicals from this class. This extensive use of pyrethroids imposes a strong selection pressure for resistance in mosquito populations, and so continuous resistance monitoring and evaluation are important. As pyrethroids have also been used for many years in the Manhica District, an area in southern Mozambique with perennial malaria transmission, an assessment of their efficacy against the local malaria vectors was conducted. METHODS: Female offspring of wild-caught Anopheles funestus s.s. females were exposed to deltamethrin, lambda-cyhalothrin and permethrin using the World Health Organization (WHO) insecticide-resistance monitoring protocols. The 3-min WHO cone bioassay was used to evaluate the effectiveness of the bed nets distributed or available for purchase in the area (Olyset, permethrin LLIN; PermaNet 2.0, deltamethrin LLIN) against An. funestus. Mosquitoes were also exposed to PermaNet 2.0 for up to 8 h in time-exposure assays. RESULTS: Resistance to pyrethroids in An. funestus s.s. was extremely high, much higher than reported in 2002 and 2009. No exposure killed more than 25.8% of the mosquitoes tested (average mortality, deltamethrin: 6.4%; lambda-cyhalothrin: 5.1%; permethrin: 19.1%). There was no significant difference in the mortality generated by 3-min exposure to any net (Olyset: 9.3% mortality, PermaNet 2.0: 6.0%, untreated: 2.0%; p = 0.2). Six hours of exposure were required to kill 50% of the An. funestus s.s. on PermaNet 2.0. CONCLUSIONS: Anopheles funestus s.s. in Manhica is extremely resistant to pyrethroids, and this area is clearly a pyrethroid-resistance hotspot. This could severely undermine vector control in this district if no appropriate countermeasures are undertaken. The National Malaria Control Programme (NMCP) of Mozambique is currently improving its resistance monitoring programme, to design and scale up new management strategies. These actions are urgently needed, as the goal of the NMCP and its partners is to reach elimination in southern Mozambique by 2020. |
Databáze: | OpenAIRE |
Externí odkaz: |
Pro tento záznam nejsou dostupné žádné jednotky.