Insecticide-treated nets provide protection against malaria to children in an area of insecticide resistance in Southern Benin.

BACKGROUND: Malaria control is heavily reliant on insecticides, especially pyrethroids. Resistance of mosquitoes to insecticides may threaten the effectiveness of insecticide-based vector control and lead to a resurgence of malaria in Africa. METHODS: In 21 villages in Southern Benin with high levels of insecticide resistance, the resistance status of local vectors was measured at the same time as the prevalence of malaria infection in resident children. RESULTS: Children who used LLINs had lower levels of malaria infection [odds ratio = 0.76 (95% CI 0.59, 0.98, p = 0.033)]. There was no evidence that the effectiveness of nets was different in high and low resistance locations (p = 0.513). There was no association between village level resistance and village level malaria prevalence (p = 0.999). CONCLUSIONS: LLINs continue to offer individual protection against malaria infection in an area of high resistance. Insecticide resistance is not a reason to stop efforts to increase coverage of LLINs in Africa.

Therapeutic efficacy of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in northwest Benin.

BACKGROUND: Artemether/lumefantrine (Coartem(®)) has been used as a treatment for uncomplicated Plasmodium falciparum infection since 2004 in Benin. This open-label, non-randomized study evaluated efficacy of artemether-lumefantrine (AL) in treatment of uncomplicated falciparum malaria in children aged 6-59 months in two malaria transmission sites in northwest Benin. METHODS: A 42-day therapeutic efficacy study was conducted between August and November 2014, in accordance with 2009 WHO guidelines. One-hundred and twenty-three children, aged 6 months to 5 years, with uncomplicated falciparum malaria were recruited into the study. The primary endpoint was parasitological cure on day 28 and day 42 while the secondary endpoints included: parasite and fever clearance, improvement in haemoglobin levels. Outcomes were classified as early treatment failure (ETF), late clinical failure, late parasitological failure, and adequate clinical and parasitological response (ACPR). RESULTS: Before PCR correction, ACPR rates were 87% (95 % CI 76.0-94.7) and 75.6%, respectively (95% CI 67.0-82.9) on day 28 and day 42. In each study site, ACPR rates were 78.3% in Djougou and 73% in Cobly on day 42. There was no ETF and after PCR correction ACPR was 100% in study population. All treatment failures were shown to be due to new infections. Fever was significantly cleared in 24 h and approximately 90% of parasites where cleared on day 1 and almost all parasites were cleared on day 2. Haemoglobin concentration showed a slight increase with parasitic clearance. CONCLUSION: AL remains an efficacious drug for the treatment of uncomplicated falciparum malaria in Benin, although higher rates of re-infection remain a concern. Surveillance needs to be continued to detect future changes in parasite sensitivity to artemisinin-based combination therapy.

High rates of parasite recrudescence following intermittent preventive treatment with sulphadoxine-pyrimethamine during pregnancy in Benin.

BACKGROUND: Despite widespread parasite resistance to sulphadoxine-pyrimethamine (SP) its use for intermittent preventative treatment during pregnancy remains the policy in Benin and throughout most of sub-Saharan Africa. METHODS: In a prospective study, 982 pregnant women were recruited in Benin and followed until delivery. The prevalence of point mutations in the pfdhfr and pfdhps genes associated with Plasmodium falciparum resistance to SP during consecutive antenatal visits was determined. Parasites clearance among women infected at SP intake was assessed by microscopy and PCR. Association between the persistence of parasites and malaria consequences, were investigated. Recurrent parasites were genotyped to identify recrudescences from re-infections. RESULTS: The prevalence of pfdhfr/pfdhps quadruple mutants (triple pfdhfr + single pfdhps) was consistently above 80% while quintuple and sextuple mutants remained low. Importantly the higly mutated parasites apparently never included the two key mutations, pfdhfr 164 L or pfdhps 540E. Based on PCR results, SP failed to clear existing parasitaemia in half (48%) of the women who were infected at IPTp schedule. The frequency of recrudescence reached 76% after the second dose. Women with persistent parasitaemia had an increased prevalence of anaemia (P = 0.03). CONCLUSION: The data presented here, highlight the inability of SP to ensure optimal antiplasmodial protection in late pregnancy, and invite urgent consideration of an alternative drug or strategy.