Papua New Guinea Malaria Indicator Survey 2016-2017: malaria prevention, infection, and treatment

Background

Malaria has been endemic throughout Papua New Guinea (PNG) with the exception of highland areas over 1600 m altitude where low temperatures prevent stable transmission. The vision expressed in the National Malaria Strategic Plan (2014-2018) is “a substantial and sustained reduction in the burden of malaria in the near term (2014-2018) and mid-term (2019-2024), and the elimination of malaria in the long term (from 2025 onward)”. In the frame of the Asia Pacific Leaders Malaria Alliance (APLMA), the PNG government envisages a malaria-free country by 2030. With financial support from The Global Fund to Fight AIDS, Tuberculosis and Malaria, the PNG National Malaria Control Program (NMCP) has distributed long-lasting insecticidal nets (LLIN) country-wide since 2004, scaled-up malaria rapid diagnostic tests (mRDT) and artemisinin-based combination therapy at health facilities since late 2011, and implemented home-based management of malaria programmes in selected areas of the country. Behaviour change campaigns supported the roll-out of preventative and curative interventions.

Methods

In the frame of a comprehensive evaluation of the NMCP, the Papua New Guinea Institute of Medical Research (PNGIMR) conducted a country-wide Malaria Indicator Survey between September 2016 and July 2017 to assess the population coverage of malaria control interventions and the prevalence of malaria infection at national and regional levels. The survey was carried out in 102 villages (18 provinces) covering 2,743 households and 15,117 individuals. A total of 11,358 blood samples were collected for diagnosis of malaria by light microscopy.

Results 

Across PNG, 80.1% of all households owned at least one LLIN and 66.7% of the population had access to an LLIN. A total of 51.1% of the household members slept under a LLIN the night before the survey. Among children <5 years, 59.5% slept under a LLIN increasing to 72.0% in households that owned at least one LLIN. Among pregnant women (15-49 years), 59.6% slept under a LLIN increasing to 70.5% if they lived in a household owning at least one LLIN. LLIN ownership and use have remained largely unchanged since 2010/11. Only 8.0% of household heads reported having received information on malaria in the past three months, mostly from health workers. Other sources of information were rarely mentioned. Below 1600 m altitude, 7.1% of the population was infected with malaria parasites, in highland areas at 1600 m and above, only 0.9%. Infections with P. falciparum were more common than infections with P. vivax. In children <5 years of age in villages <1600 m altitude, 9.5% were infected with malaria parasites, while no malaria infections were found in children in villages at 1600 m and above. The provinces with the highest prevalence values were Madang (16.0%), Milne Bay (10.8%), East Sepik (8.8%), New Ireland (8.7%), and Sandaun (7.9%). While in Madang and East Sepik Provinces almost all surveyed villages had >10% prevalence in adults and similar values in young children (up to 57.7% in one Madang village), the other lowlands provinces had pockets of high prevalence as well as villages with infections only in older children and adults, and villages with no infections at all. In the Highlands Region, malaria infected individuals were found in only three villages, where none of the infections was in children, suggesting importation of infections rather than local transmission. Compared to the previous survey in 2013/14, there has been a massive resurgence in malaria across PNG. A recent fever was reported by 3.6% of all household members and 1.3% had acute fever on the day of the survey. Fever was most common in young children. Anaemia was detected in 62.5% of all household members and 3.5% had severe anaemia. Anaemia was less common in the Highlands regions and decreased with age. Of all children 2-9 years of age, 1.5% had an enlarged spleen (splenomegaly), most frequently in the provinces of Sandaun (17.8%), New Ireland (3.8%), Madang (2.5%) and Gulf (2.5%). For 42.9% of recent fever cases in the general population and for 45.3% in children <5 years, treatment was sought outside the person’s home. The most common source of treatment were health facilities (40.6% in the general population, 44.5% in children <5 years). The most frequently cited reason for not attending a health facility included long distance to the nearest facility (in combination with a lack of money for transport or medication, and a lack of medicines or poor quality of care at the facility), a perceived lack of severity of the illness and reliance on home treatment. A diagnostic test was performed in 22.6% cases in the general population and in 24.8% of the cases in children <5 years. The most commonly used drugs were antipyretics (29.6%) and antibiotics (20.2%). An antimalarial was taken by 16.5% of the fever cases and by 13.4% of children <5 years with a recent fever. The most frequently used antimalarials were the first-line treatment artemether-lumefantrine (13.9%), followed by artemether or artesunate injections (13.3%) and primaquine (12.7%). Use of artemisinin monotherapies was rarely reported. Artemether-lumefantrine was used by 85.3% of reportedly test-positive persons, and by 89.6% of test-positive children <5 years. Targets and results of key indicators used in the evaluation of the Global Fund support to the PNG NMCP are listed in the table on the following page. Maps depicting LLIN coverage and malaria prevalence by province in four consecutive surveys are shown on subsequent pages.

Conclusion 

The historical achievement of the PNG national malaria control program, i.e. the reduction of malaria prevalence to <1% by 2013/14, has suffered a major setback in the last three years. Results from this and other surveys conducted by PNGIMR suggest that, in general, intervention coverage has plateaued at best. In consideration of the observed trend, the longer-term goal of malaria elimination from PNG by 2030 is less likely now than it was at the time the National Malaria Strategic Plan (2014-2018) was drafted. The current resurgence in malaria is likely to worsen unless malaria control is re-intensified without delay, inclusive of the provision of sufficient funding for vector control, diagnosis, treatment, behaviour change campaigns and operational research.