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PAMCA Anopheles genomics programme - First investigation of genetic diversity in malaria vectors in the Democratic Republic of Congo and the implications for the spread of insecticide resistance (1264-VO-CD-WATSENGA)

Location: Congo (Democratic Republic of the Congo) (CD).

Mosquito

The study sites for this project (Haut Katanga in Kapolowe, Kongo Central in Kimpese and Kasai Central in Mikalayi) are across ecological zones and land use of the Democtracic Republic of Congo. Historically, malaria cases are very high throughout the year in the three selected study sites. To supplement LLINs with new tools for vector control, the selected sites were advised by the NMCP based on the 2016-2020 national insecticide resistance management plan which recommended the implementation of evidence based integrated vector control strategies. The results from these diversified ecosystems will show the An. gambiae s.l genetic population structure and genes flow, essential for rational vector control decision making. The design of new tools for mosquito control using gene-drive systems will need to take into account the high levels of genetic diversity in natural mosquito populations.

A minimum of 50 females An. gambiae s.l. mosquitoes will undergo whole genome sequencing from three points along a transect during the rainy and dry seasons at each 2 km circle diameter from the forest into savannah in Mikalayi, Kimpese and from the river side of the lake Tshangalele to the urban in Kapolowe for performing whole genome sequencing. We expect to sequence An. coluzzii, An. gambiae and hybrids (30 to 50 specimens) to analyze the Population structure (PCA, FST) to determine genetically distinct populations and effect of geographical distance and species. Study parameters of genetic diversity within populations (nucleotide diversity, site frequency spectra) to look for evidence of demographic differences between populations (e.g., population size). We will also perform genome-wide scans for signals of recent selection, to determine whether there has been selection for insecticide, and if so, what genes are under selection.

Currently, DRC is one of the rare countries providing an excellent study site for preliminary investigations in genetic diversity and its possible associations with the spread of insecticide resistance. There are areas of large-scale cotton and rice production with longstanding use of pyrethroid insecticides; such urban areas with expected higher levels of pollution and rural areas with least or no use at all of insecticide on either crops protection or malaria prevention. By selecting samples from a wide variety of collection sites throughout the country; and by comparing the resistance level and the frequency associated alleles in each population; we will begin to form a picture of the likely sources of selection pressure for insecticide resistance in malaria vectors.

Contributors:

  • Wat’Senga Tezzo Nsimba Jean-Francis Institut National de Recherche Biomédicale (INRB), DRC
  • Muyembe Tamfum Jean-Jacques Institut National de Recherche Biomédicale (INRB), DRC
  • Emile Makima Zola Manzambi Institut National de Recherche Biomédicale (INRB), DRC
  • Alex Asidi Institut National de Recherche Biomédicale (INRB), DRC
  • Rodrigue Fiacre Agossa Institut National de Recherche Biomédicale (INRB), DRC
  • Irish Seth Centers for Disease Control and Prevention, USA
  • David Weetman Liverpool School of Tropical Medicine (LSTM), UK
  • Jennifer Armistead President’s Malaria Initiative (PMI), US