Intensity of pyrethroid resistance in Anopheles gambiae before and after a mass distribution of insecticide-treated nets in Kinshasa and in 11 provinces of the Democratic Republic of Congo.

Autor: Wat'senga F; Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo., Agossa F; USAID President's Malaria Initiative, VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA., Manzambi EZ; Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo., Illombe G; Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo., Mapangulu T; Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo., Muyembe T; Institut National de Recherche Biomédicale, PO Box 1192, Kinshasa, Democratic Republic of Congo., Clark T; USAID President's Malaria Initiative, VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA., Niang M; U.S. President's Malaria Initiative, U.S. Agency for International Development, Kinshasa, Democratic Republic of the Congo., Ntoya F; U.S. President's Malaria Initiative, U.S. Agency for International Development, Kinshasa, Democratic Republic of the Congo., Sadou A; U.S. President's Malaria Initiative, U.S. Agency for International Development, Kinshasa, Democratic Republic of the Congo., Plucinski M; U.S. President's Malaria Initiative and Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA, 30329, USA., Li Y; U.S. President's Malaria Initiative and Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA, 30329, USA., Messenger LA; U.S. President's Malaria Initiative and Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA, 30329, USA.; London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK., Fornadel C; U.S. President's Malaria Initiative, United States Agency for International Development, Bureau for Global Health, Office of Infectious Disease, 2100 Crystal Drive, Arlington, VA, 22202, USA., Oxborough RM; USAID President's Malaria Initiative, VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA., Irish SR; U.S. President's Malaria Initiative and Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA, 30329, USA. xjs7@cdc.gov.
Jazyk: angličtina
Zdroj: Malaria journal [Malar J] 2020 Apr 30; Vol. 19 (1), pp. 169. Date of Electronic Publication: 2020 Apr 30.
DOI: 10.1186/s12936-020-03240-6
Abstrakt: Background: Between 2011 and 2018, an estimated 134.8 million pyrethroid-treated long-lasting insecticidal nets (LLINs) were distributed nationwide in the Democratic Republic of Congo (DRC) for malaria control. Pyrethroid resistance has developed in DRC in recent years, but the intensity of resistance and impact on LLIN efficacy was not known. Therefore, the intensity of resistance of Anopheles gambiae sensu lato (s.l.) to permethrin and deltamethrin was monitored before and after a mass distribution of LLINs in Kinshasa in December 2016, and in 6 other sites across the country in 2017 and 11 sites in 2018.
Methods: In Kinshasa, CDC bottle bioassays using 1, 2, 5, and 10 times the diagnostic dose of permethrin and deltamethrin were conducted using An. gambiae s.l. collected as larvae and reared to adults. Bioassays were conducted in four sites in Kinshasa province 6 months before a mass distribution of deltamethrin-treated LLINs and then two, six, and 10 months after the distribution. One site in neighbouring Kongo Central province was used as a control (no mass campaign of LLIN distribution during the study). Nationwide intensity assays were conducted in six sites in 2017 using CDC bottle bioassays and in 11 sites in 2018 using WHO intensity assays. A sub-sample of An. gambiae s.l. was tested by PCR to determine species composition and frequency of kdr-1014F and 1014S alleles.
Results: In June 2016, before LLIN distribution, permethrin resistance intensity was high in Kinshasa; the mean mortality rate was 43% at the 5× concentration and 73% at the 10× concentration. Bioassays at 3 time points after LLIN distribution showed considerable variation by site and time and there was no consistent evidence for an increase in pyrethroid resistance intensity compared to the neighbouring control site. Tests of An. gambiae s.l. in 6 sites across the country in 2017 and 11 sites in 2018 showed all populations were resistant to the diagnostic doses of 3 pyrethroids. In 2018, the intensity of resistance varied by site, but was generally moderate for all three pyrethroids, with survivors at ×5 the diagnostic dose. Anopheles gambiae sensu stricto (s.s.) was the most common species identified across 11 sites in DRC, but in Kinshasa, An. gambiae s.s. (91%) and Anopheles coluzzii (8%) were sympatric.
Conclusions: Moderate or high intensity pyrethroid resistance was detected nationwide in DRC and is a serious threat to sustained malaria control with pyrethroid LLINs. Next generation nets (PBO nets or bi-treated nets) should be considered for mass distribution.
Databáze: MEDLINE
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