Malaria vector composition and insecticide susceptibility status in Guinea Conakry, West Africa

Authors

  • S. B. VEZENEGHO,

    1. Vector Control Reference Unit, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
    2. School of Molecular Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
    Search for more papers by this author
  • B. D. BROOKE,

    1. Vector Control Reference Unit, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
    2. Malaria Entomology Research Unit, School of Pathology, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
    Search for more papers by this author
  • R. H. HUNT,

    1. Vector Control Reference Unit, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
    2. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
    Search for more papers by this author
  • M. COETZEE,

    1. Vector Control Reference Unit, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
    2. Malaria Entomology Research Unit, School of Pathology, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
    Search for more papers by this author
  • L. L. KOEKEMOER

    Corresponding author
    1. Vector Control Reference Unit, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
    2. Malaria Entomology Research Unit, School of Pathology, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
    Search for more papers by this author

Dr L. L. Koekemoer, Vector Control Reference Unit, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, Johannesburg, South Africa. Tel.: + 27 11 386 6484; fax: + 27 11 386 6481; e-mail: lizettek@nicd.ac.za

Abstract.

This study provides data on malaria vector species composition and insecticide susceptibility status from three localities in Guinea Conakry. A total of 497 mosquitoes were collected resting indoors and morphologically identified as belonging to the Anopheles gambiae complex. The majority of these were An. gambiae s.s. (99.6%), but a small percentage (0.4%) were identified as Anopheles arabiensis. Thirty-four Anopheles funestus s.s. were also collected. The molecular S form of An. gambiae s.s. was predominant over the M form in Siguiri (95%) and Boffa (97.4%), whereas at Mt Nimba the M form was more abundant (61.4%) than the S form (38.1%). One hybrid M/S specimen was recorded from Mt Nimba. Siguiri populations showed high levels of resistance to DDT, dieldrin and bendiocarb. Anopheles gambiae from Boffa were largely susceptible to the insecticides tested. At Mt Nimba, resistance to DDT and bendicocarb was detected. Biochemical enzyme analysis showed that an altered acetylcholinesterase is operating in the field at low levels. The frequency of the 1014F kdr allele in the An. gambiae S form was 0.24 at Siguiri and 0.14 at Mt Nimba. A single RR specimen was found in the M form. The heterogeneity in species composition and resistance profiles between sites requires vector control interventions to be tailored to each site based on the data collected from ongoing monitoring and surveillance.

Ancillary