Insecticide-treated nets and malaria prevalence, Papua New Guinea, 2008–2014

Abstract

ObjectiveTo investigate changes in malaria prevalence in Papua New Guinea after the distribution of long-lasting Insecticide-treated nets, starting in 2004, and the introduction of artemisinin-based combination therapy in 2011.MethodsTwo malaria surveys were conducted in 2010–2011 and 2013–2014. They included 77 and 92 randomly selected villages, respectively. In each village, all members of 30 randomly selected households gave blood samples and were assessed for malaria infection by light microscopy. In addition, data were obtained from a malaria survey performed in 2008–2009.ResultsThe prevalence of malaria below 1600 m in altitude decreased from 11.1% (95% confidence interval, CI: 8.5–14.3) in 2008–2009 to 5.1% (95% CI 3.6–7.4) in 2010–2011 and 0.9% (95% CI 0.6–1.5) in 2013–2014. Prevalence decreased with altitude. Plasmodium falciparum was more common than P. vivax overall, but not everywhere, and initially the prevalence of P. vivax infection decreased more slowly than P. falciparum infection. Malaria infections were clustered in households. In contrast to findings in 2008–2009, no significant association between net use and prevalence was found in the later two surveys. The prevalence of both fever and splenomegaly also decreased but their association with malaria infection became stronger.ConclusionLarge-scale insecticide-treated net distribution was associated with an unprecedented decline in malaria prevalence throughout Papua New Guinea, including epidemic-prone highland areas. The decline was accompanied by broader health benefits, such as decreased morbidity. Better clinical management of nonmalarial fever and research into residual malaria transmission are required.

Repeated mosquito net distributions, improved treatment, and trends in malaria cases in sentinel health facilities in Papua New Guinea

“…Since this last scale-up, the malaria burden in PNG has steadily decreased as reflected in declining prevalence of infection [8], incidence [9] and transmission [10]. However, malaria control efforts are intrinsically affected by the great environmental and socio-cultural diversity across the country, including a major mountain range over the length of the main island, dense rainforests in the highlands, lowland and coastal areas, and large wetlands surrounding major rivers [2].…”

“…While changes in malaria prevalence have been consistently investigated since 2008 [8], national trends in malaria incidence are inconclusive and difficult to interpret due to confounding effects of the scale-up of RDTs, changes in health facility reporting forms, and inconsistencies in routine reporting [7].…”

A Randomized Open-Label Evaluation of the Antimalarial Prophylactic Efficacy of Azithromycin-Piperaquine versus Sulfadoxine-Pyrimethamine in Pregnant Papua New Guinean Women

“…This finding suggests that there was insufficient statistical power to show superiority of AZ-PQ over single-dose SP as IPTp for prevention of parasitemia in our participants. The most likely explanation for the lower rate of malaria during pregnancy in the present study is that the PNG National Malaria Control Plan was implemented between 2008 and 2014; this involved widespread distribution of long-lasting-insecticide-treated bed nets and rapid diagnostic tests and a change of treatment policy to artemether-lumefantrine from older drugs such as CQ and SP, with implications for reduced transmission (40). There was a subsequent decline in the national malaria prevalence, from 11.1% in 2009 to 0.9% in 2014 (40).…”

“…The most likely explanation for the lower rate of malaria during pregnancy in the present study is that the PNG National Malaria Control Plan was implemented between 2008 and 2014; this involved widespread distribution of long-lasting-insecticide-treated bed nets and rapid diagnostic tests and a change of treatment policy to artemether-lumefantrine from older drugs such as CQ and SP, with implications for reduced transmission (40). There was a subsequent decline in the national malaria prevalence, from 11.1% in 2009 to 0.9% in 2014 (40). Although all of the present participants were provided an insecticide-treated bed net on day 42 as an alternative to monthly SP prophylaxis, it is likely that many had already been using a bed net.…”

Status of Insecticide Resistance in Papua New Guinea: An Update from Nation-Wide Monitoring of Anopheles Mosquitoes

“…LLINs have significantly contributed to the declining malaria burden in the country. 2,3 Insecticide resistance (IR) has arisen in anopheline populations in other malaria-endemic nations, particularly in Africa and Asia, after the distribution of pyrethroid-treated LLINs and the use of pyrethroids for indoor residual spraying (IRS), agriculture, and household use in repellents and aerosol sprays. 4,5 Till date, pyrethroid resistance has not been documented in PNG.…”