Emery Metelo-Matubi
Faculté de Médecine, Université de Bandundu, B.P 548 Bandundu-ville, Bandundu, République Démocratique de Congo; Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo; Faculté des Sciences, Département de Biologie, Unité de Recherche Entomologique, B.P 190 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Josué Zanga
Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Guillaume Binene
Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo
Nono Mvuama
Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Solange Ngamukie
Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Jadis Nkey
Faculté de Médecine, Université de Bandundu, B.P 548 Bandundu-ville, Bandundu, République Démocratique de Congo
Pauline Schopp
United States President´s Malaria Initiative and Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA
Maxwell Bamba
Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Seth Irish
United States President´s Malaria Initiative and Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA
Jean Nguya-Kalemba-Maniania
International Centre of Insect Physiology and Ecology, P.O. Box 30772 - 00100 GPO, Nairobi, Kenya
Sylvie Fasine
Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo
Jonas Nagahuedi
Faculté des Sciences, Département de Biologie, Unité de Recherche Entomologique, B.P 190 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Jean-Jacques Muyembe
Institut National de Recherche Biomédicale, B.P 1197 KIN 1, Kinshasa, République Démocratique de Congo
Paul Mansiangi
Faculté de Médecine, Ecole de Santé Publique, Département de Santé Environnementale, B.P 834 KIN XI, Université de Kinshasa, Kinshasa, République Démocratique de Congo
Abstract
Introduction: insecticide-treated nets (ITNs) remain the mainstay of malaria vector control in the Democratic Republic of Congo. However, insecticide resistance of malaria vectors threatens their effectiveness. Entomological inoculation rates and insecticide susceptibility in Anopheles gambiae s.l. were evaluated before and after mass distribution of ITNs in Bandundu City for possible occurrence of resistance.
Methods: a cross-sectional study was conducted from 15th July 2015 to 15th June 2016. Adult mosquitoes were collected using pyrethrum spray catches and human landing catches and identified to species level and tested for the presence of sporozoites. Bioassays were carried out before and after distribution of ITNs to assess the susceptibility of adult mosquitoes to insecticides. Synergist bioassays were also conducted and target site mutations assessed using Polymerase chain reaction (PCR).
Results: a total of 1754 female An. gambiae s.l. were collected before and after deployment of ITNs. Fewer mosquitoes were collected after the distribution of ITNs. However, there was no significant difference in sporozoite rates or the overall entomological inoculation rate before and after the distribution of ITNs. Test-mosquitoes were resistant to deltamethrin, permethrin, and Dichlorodiphenyltrichloroethane but susceptible to bendiocarb. Pre-exposure of mosquitoes to Piperonyl butoxide increased their mortality after exposure to permethrin and deltamethrin. The frequency of the Kinase insert domain receptor (kdr)-West gene increased from 92 to 99% before and after the distribution of nets, respectively.
Conclusion: seasonal impacts could be a limiting factor in the analysis of these data; however, the lack of decrease in transmission after the distribution of new nets could be explained by the high-level of resistance to pyrethroid.
