Effect of Transmission Reduction by Insecticide-Treated Bednets (ITNs) on Antimalarial Drug Resistance in Western Kenya

Shah, Monica, Kariuki, Simon, Vanden Eng, Jodi, Blackstock, Anna J., Garner, Kimberly, Gatei, Wangeci, Gimnig, John E., Lindblade, Kim, Terlouw, Anja ORCID: https://orcid.org/0000-0001-5327-8995, terKuile, Feiko ORCID: https://orcid.org/0000-0003-3663-5617, Hawley, William A., Phillips-Howard, Penelope, Nahlen, Bernard, Walker, Edward, Hamel, Mary J., Slutsker, Laurence and Shi, Ya Ping (2011) 'Effect of Transmission Reduction by Insecticide-Treated Bednets (ITNs) on Antimalarial Drug Resistance in Western Kenya'. PLoS ONE, Vol 6, Issue 11, e26746.

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Abstract

Despite the clear public health benefit of insecticide-treated bednets (ITNs), the impact of malaria transmission-reduction by vector control on the spread of drug resistance is not well understood. In the present study, the effect of sustained transmission reduction by ITNs on the prevalence of Plasmodium falciparum gene mutations associated with resistance to the antimalarial drugs sulfadoxine-pyrimethamine (SP) and chloroquine (CQ) in children under the age of five years was investigated during an ITN trial in Asembo area, western Kenya. During the ITN trial, the national first line antimalarial treatment changed from CQ to SP. Smear-positive samples collected from cross sectional surveys prior to ITN introduction (baseline, n = 250) and five years post-ITN intervention (year 5 survey, n = 242) were genotyped for single nucleotide polymorphisms (SNPs) at dhfr-51, 59, 108, 164 and dhps-437, 540 (SP resistance), and pfcrt-76 and pfmdr1-86 (CQ resistance). The association between the drug resistance mutations and epidemiological variables was evaluated. There were significant increases in the prevalence of SP dhps mutations and the dhfr/dhps quintuple mutant, and a significant reduction in the proportion of mixed infections detected at dhfr-51, 59 and dhps-437, 540 SNPs from baseline to the year 5 survey. There was no change in the high prevalence of pfcrt-76 and pfmdr1-86 mutations. Multivariable regression analysis further showed that current antifolate use and year of survey were significantly associated with more SP drug resistance mutations. These results suggest that increased antifolate drug use due to drug policy change likely led to the high prevalence of SP mutations 5 years post-ITN intervention and reduced transmission had no apparent effect on the existing high prevalence of CQ mutations. There is no evidence from the current study that sustained transmission reduction by ITNs reduces the prevalence of genes associated with malaria drug resistance.

Item Type:	Article
Subjects:	QV Pharmacology > Anti-Inflammatory Agents. Anti-Infective Agents. Antineoplastic Agents > QV 256 Antimalarials QW Microbiology and Immunology > QW 45 Microbial drug resistance. General or not elsewhere classified. WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WA Public Health > Preventive Medicine > WA 240 Disinfection. Disinfestation. Pesticides (including diseases caused by)
Digital Object Identifer (DOI):	https://doi.org/10.1371/journal.pone.0026746
Depositing User:	Martin Chapman
Date Deposited:	14 Apr 2014 15:24
Last Modified:	13 Sep 2019 13:10
URI:	https://archive.lstmed.ac.uk/id/eprint/3662

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