TY - JOUR
T1 - Implications of insecticide resistance for malaria vector control
with long-lasting insecticidal nets: a WHO-coordinated,
prospective, international, observational cohort study
AU - Kleinschmidt, Immo
AU - Bradley, John
AU - Knox, Tessa Bellamy
AU - Mnzava, Abraham Peter
AU - Kafy, Hmooda Toto
AU - Mbogo, Charles
AU - Ismail, Bashir Adam
AU - Bigoga, Jude D.
AU - Adechoubou, Alioun
AU - Raghavendra, Kamaraju
AU - Cook, Jackie
AU - Malik, Elfatih M.
AU - Nkuni, Zinga José
AU - Macdonald, Michael
AU - Bayoh, Nabie
AU - Ochomo, Eric
AU - Fondjo, Etienne
AU - Awono-Ambene, Herman Parfait
AU - Etang, Josiane
AU - Akogbeto, Martin
AU - Bhatt, Rajendra M.
AU - Chourasia, Mehul Kumar
AU - Swain, Dipak K.
AU - Kinyari, Teresa
AU - Subramaniam, Krishanthi
AU - Massougbodji, Achille
AU - Okê-Sopoh, Mariam
AU - Ogouyemi-Hounto, Aurore
AU - Kouambeng, Celestin
AU - Abdin, Mujahid Sheikhedin
AU - West, Philippa
AU - Elmardi, Khalid
AU - Cornelie, Sylvie
AU - Corbel, Vincent
AU - Valecha, Neena
AU - Mathenge, Evan
AU - Kamau, Luna
AU - Lines, Jonathan
AU - Donnelly, Martin
PY - 2018/4/9
Y1 - 2018/4/9
N2 - BackgroundScale-up of insecticide-based interventions has averted more than 500 million malaria cases since 2000. Increasing insecticide resistance could herald a rebound in disease and mortality. We aimed to investigate whether insecticide resistance was associated with loss of effectiveness of long-lasting insecticidal nets and increased malaria disease burden.MethodsThis WHO-coordinated, prospective, observational cohort study was done at 279 clusters (villages or groups of villages in which phenotypic resistance was measurable) in Benin, Cameroon, India, Kenya, and Sudan. Pyrethroid long-lasting insecticidal nets were the principal form of malaria vector control in all study areas; in Sudan this approach was supplemented by indoor residual spraying. Cohorts of children from randomly selected households in each cluster were recruited and followed up by community health workers to measure incidence of clinical malaria and prevalence of infection. Mosquitoes were assessed for susceptibility to pyrethroids using the standard WHO bioassay test. Country-specific results were combined using meta-analysis.FindingsBetween June 2, 2012, and Nov 4, 2016, 40 000 children were enrolled and assessed for clinical incidence during 1·4 million follow-up visits. 80 000 mosquitoes were assessed for insecticide resistance. Long-lasting insecticidal net users had lower infection prevalence (adjusted odds ratio [OR] 0·63, 95% CI 0·51–0·78) and disease incidence (adjusted rate ratio [RR] 0·62, 0·41–0·94) than did non-users across a range of resistance levels. We found no evidence of an association between insecticide resistance and infection prevalence (adjusted OR 0·86, 0·70–1·06) or incidence (adjusted RR 0·89, 0·72–1·10). Users of nets, although significantly better protected than non-users, were nevertheless subject to high malaria infection risk (ranging from an average incidence in net users of 0·023, [95% CI 0·016–0·033] per person-year in India, to 0·80 [0·65–0·97] per person year in Kenya; and an average infection prevalence in net users of 0·8% [0·5–1·3] in India to an average infection prevalence of 50·8% [43·4–58·2] in Benin).InterpretationIrrespective of resistance, populations in malaria endemic areas should continue to use long-lasting insecticidal nets to reduce their risk of infection. As nets provide only partial protection, the development of additional vector control tools should be prioritised to reduce the unacceptably high malaria burden.
AB - BackgroundScale-up of insecticide-based interventions has averted more than 500 million malaria cases since 2000. Increasing insecticide resistance could herald a rebound in disease and mortality. We aimed to investigate whether insecticide resistance was associated with loss of effectiveness of long-lasting insecticidal nets and increased malaria disease burden.MethodsThis WHO-coordinated, prospective, observational cohort study was done at 279 clusters (villages or groups of villages in which phenotypic resistance was measurable) in Benin, Cameroon, India, Kenya, and Sudan. Pyrethroid long-lasting insecticidal nets were the principal form of malaria vector control in all study areas; in Sudan this approach was supplemented by indoor residual spraying. Cohorts of children from randomly selected households in each cluster were recruited and followed up by community health workers to measure incidence of clinical malaria and prevalence of infection. Mosquitoes were assessed for susceptibility to pyrethroids using the standard WHO bioassay test. Country-specific results were combined using meta-analysis.FindingsBetween June 2, 2012, and Nov 4, 2016, 40 000 children were enrolled and assessed for clinical incidence during 1·4 million follow-up visits. 80 000 mosquitoes were assessed for insecticide resistance. Long-lasting insecticidal net users had lower infection prevalence (adjusted odds ratio [OR] 0·63, 95% CI 0·51–0·78) and disease incidence (adjusted rate ratio [RR] 0·62, 0·41–0·94) than did non-users across a range of resistance levels. We found no evidence of an association between insecticide resistance and infection prevalence (adjusted OR 0·86, 0·70–1·06) or incidence (adjusted RR 0·89, 0·72–1·10). Users of nets, although significantly better protected than non-users, were nevertheless subject to high malaria infection risk (ranging from an average incidence in net users of 0·023, [95% CI 0·016–0·033] per person-year in India, to 0·80 [0·65–0·97] per person year in Kenya; and an average infection prevalence in net users of 0·8% [0·5–1·3] in India to an average infection prevalence of 50·8% [43·4–58·2] in Benin).InterpretationIrrespective of resistance, populations in malaria endemic areas should continue to use long-lasting insecticidal nets to reduce their risk of infection. As nets provide only partial protection, the development of additional vector control tools should be prioritised to reduce the unacceptably high malaria burden.
U2 - 10.1016/s1473-3099(18)30172-5
DO - 10.1016/s1473-3099(18)30172-5
M3 - Article
SN - 1473-3099
VL - 18
SP - 640
EP - 649
JO - The Lancet Infectious Diseases
JF - The Lancet Infectious Diseases
IS - 6
ER -
