title: Insecticide resistance and role in malaria transmission of Anopheles funestus populations from Zambia and Zimbabwe.
abstract: BACKGROUND
  Two mitochondrial DNA clades have been described in Anopheles funestus populations from southern Africa. Clade I is common across the continent while clade II is known only from Mozambique and Madagascar. The specific biological status of these clades is at present unknown. We investigated the possible role that each clade might play in the transmission of Plasmodium falciparum and the insecticide resistance status of An. funestus from Zimbabwe and Zambia.
  
  
  METHODS
  Mosquitoes were collected inside houses from Nchelenge District, Zambia and Honde Valley, Zimbabwe in 2013 and 2014. WHO susceptibility tests, synergist assays and resistance intensity tests were conducted on wild females and progeny of wild females. ELISA was used to detect Plasmodium falciparum circumsporozoite protein. Specimens were identified to species and mtDNA clades using standard molecular methods.
  
  
  RESULTS
  The Zimbabwean samples were all clade I while the Zambian population comprised 80% clade I and 20% clade II in both years of collection. ELISA tests gave an overall infection rate of 2.3% and 2.1% in 2013, and 3.5% and 9.2% in 2014 for Zimbabwe and Zambia respectively. No significant difference was observed between the clades. All populations were resistant to pyrethroids and carbamates but susceptible to organochlorines and organophosphates. Synergist assays indicated that pyrethroid resistance is mediated by cytochrome P450 mono-oxygenases. Resistance intensity tests showed high survival rates after 8-hrs continuous exposure to pyrethroids but exposure to bendiocarb gave the same results as the susceptible control.
  
  
  CONCLUSIONS
  This is the first record of An. funestus mtDNA clade II occurring in Zambia. No evidence was found to suggest that the clades are markers of biologically separate populations. The ability of An. funestus to withstand prolonged exposure to pyrethroids has serious implications for the use of these insecticides, either through LLINs or IRS, in southern Africa in general and resistance management strategies should be urgently implemented.
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. kwangshik@gmail.com.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. kwangshik@gmail.com.|School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu, 702-701, Korea. kwangshik@gmail.com.
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Choi
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. riannc@nicd.ac.za.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. riannc@nicd.ac.za.
authors.forename: Riann
authors.initials: R
authors.lastname: Christian
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. nardiniluisa1@gmail.com.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. nardiniluisa1@gmail.com.
authors.forename: Luisa
authors.initials: L
authors.lastname: Nardini
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. oliverw@nicd.ac.za.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. oliverw@nicd.ac.za.
authors.forename: Oliver R
authors.initials: OR
authors.lastname: Wood
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. eunicea@nicd.ac.za.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. eunicea@nicd.ac.za.
authors.forename: Eunice
authors.initials: E
authors.lastname: Agubuzo
authors.affiliation: Tropical Diseases Research Centre, Ndola, Zambia. mulebam@tdrc.org.zm.
authors.forename: Mbanga
authors.initials: M
authors.lastname: Muleba
authors.affiliation: Biomedical Research and Training Institute, Harare, Zimbabwe. smunyati@brti.co.zw.
authors.forename: Shungu
authors.initials: S
authors.lastname: Munyati
authors.affiliation: National Institute for Health Research, Harare, Zimbabwe. aramumakuwaza@gmail.com.
authors.forename: Aramu
authors.initials: A
authors.lastname: Makuwaza
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. lizettek@nicd.ac.za.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. lizettek@nicd.ac.za.
authors.forename: Lizette L
authors.initials: LL
authors.lastname: Koekemoer
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. basilb@nicd.ac.za.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. basilb@nicd.ac.za.
authors.forename: Basil D
authors.initials: BD
authors.lastname: Brooke
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. richardhhunt@gmail.com.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Hunt
authors.affiliation: Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. maureenc@nicd.ac.za.|Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa. maureenc@nicd.ac.za.
authors.forename: Maureen
authors.initials: M
authors.lastname: Coetzee
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000235:genetics; D001681:Biological Assay; D004272:DNA, Mitochondrial / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides / Q000494:pharmacology*; D016778:Malaria, Falciparum / Q000635:transmission*; D010574:Pesticide Synergists / Q000494:pharmacology; D015024:Zambia / Q000453:epidemiology; D015030:Zimbabwe / Q000453:epidemiology
chemical_list: D004272:DNA, Mitochondrial; D007306:Insecticides; D010574:Pesticide Synergists