The effect of insecticide-treated bed nets on the incidence and prevalence of malaria in children in an area of unstable seasonal transmission in western Myanmar

Abstract

BackgroundInsecticide-treated bed nets (ITN) reduce malaria morbidity and mortality consistently in Africa, but their benefits have been less consistent in Asia. This study’s objective was to evaluate the malaria protective efficacy of village-wide usage of ITN in Western Myanmar and estimate the cost-effectiveness of ITN compared with extending early diagnosis and treatment services.MethodsA cluster-randomized controlled trial was conducted in Rakhine State to assess the efficacy of ITNs in preventing malaria and anaemia in children and their secondary effects on nutrition and development. The data were aggregated for each village to obtain cluster-level infection rates. In total 8,175 children under 10 years of age were followed up for 10 months, which included the main malaria transmission period. The incidence and prevalence of Plasmodium falciparum and Plasmodium vivax infections, and the biting behaviour of Anopheles mosquitoes in the area were studied concurrently. The trial data along with costs for current recommended treatment practices were modelled to estimate the cost-effectiveness of ITNs compared with, or in addition to extending the coverage of early diagnosis and treatment services.ResultsIn aggregate, malaria infections, spleen rates, haemoglobin concentrations, and weight for height, did not differ significantly during the study period between villages with and without ITNs, with a weighted mean difference of −2.6 P. falciparum episodes per 1,000 weeks at risk (95% Confidence Interval −7 to 1.8). In areas with a higher incidence of malaria there was some evidence ITN protective efficacy. The economic analysis indicated that, despite the uncertainty and variability in their protective efficacy in the different study sites, ITN could still be cost-effective, but not if they displaced funding for early diagnosis and effective treatment which is substantially more cost-effective.ConclusionIn Western Myanmar deployment of ITNs did not provide consistent protection against malaria in children living in malaria endemic villages. Early diagnosis and effective treatment is a more cost effective malaria control strategy than deployment of ITNs in this area where the main vector bites early in the evening, often before people are protected by an ITN.

Prevalence of Malaria among Neonates Presenting with Fever in Port Harcourt, Nigeria

“…It could also be due to the common reason that sleeping under the net was too hot and uncomfortable [24]. The observation in the present study that more than half of the neonates whose mothers used insecticide treated nets had positive malaria parasite was also the case in Myanmar [25]. This could be due to poor adherence to the instructions as to the correct use of ITN [25].…”

“…The observation in the present study that more than half of the neonates whose mothers used insecticide treated nets had positive malaria parasite was also the case in Myanmar [25]. This could be due to poor adherence to the instructions as to the correct use of ITN [25]. It could also be attributed to the fact that the anopheles mosquitoes also bite in the early hours of the morning as well as early evening when the mother is not necessarily under the ITN [25].…”

“…This could be due to poor adherence to the instructions as to the correct use of ITN [25]. It could also be attributed to the fact that the anopheles mosquitoes also bite in the early hours of the morning as well as early evening when the mother is not necessarily under the ITN [25].…”

Characterizing, controlling and eliminating residual malaria transmission

“…dirus , the most important vector in the greater Mekong region where containment of growing parasite resistance to artemisinin-based drugs will most probably require elimination of transmission at sub-regional level [74].

Figure 9 Estimates of the proportion of human exposure to Asian malaria vector populations that occurs indoors for both unprotected residents ( π h,i ) and users of long-lasting insecticidal nets ( π h,i,n ), from the Solomon Islands [75] , Laos [76] , Iran [17] and Myanmar [77, 78] , calculated as previously described [71, 72] , except that in the Iranian examples, indoor and outdoor biting densities were assumed to be equal because they were not reported separately [17] . Original data from the Solomon Islands and Myanmar were kindly provided by Hugo Bugoro, Tanya Russell, Frank Smithuis and Nick White.

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Towards Malaria Elimination: Monitoring and Evaluation of the “1-3-7” Approach at the China–Myanmar Border

“…Myanmar has the heaviest malaria burden in the Great Mekong Subregion (GMS), and malaria control activities in this country was compromised because of the limited availability of curative services, the difficulties in accessing malarious areas, and the relatively high costs of effective treatment of multidrug-resistant malaria. 10 In addition, the spread of artemisinin resistance that emerged in the Thai-Cambodian border may be catastrophic to malaria control and elimination in bordering counties in the GMS. 11,12 Data from the Chinese malaria surveillance system from 2005 to 2014 were used in this study, because the Chinese web-based disease reporting system was established in 2004 and data going back to 2005 were available.…”