The impact of malaria on severe illness and mortality in Papua New Guinean children

[Truncated abstract] In Papua New Guinea (PNG), nearly 10% of children will die before their 5th birthday. The absence of contemporary data and the lack of vital reporting mechanisms in PNG result in substantial uncertainty in the overall estimates of mortality. This uncertainty is compounded when cause- or pathogen-specific mortality is estimated. This thesis focuses on malaria, caused by the parasites Plasmodium falciparum and P. vivax that are endemic to many coastal areas of PNG, and its impact on severe childhood illness and mortality. Official estimates suggest that malaria accounts for 15% of deaths in children older than 1 month across the country. However, the studies on which mortality estimates are based were performed in areas without intense malaria transmission. Therefore they may not accurately reflect the true impact of malaria in coastal populations, where transmission is hyperendemic and P. vivax is co-transmitted with P. falciparum. As in African settings, where malaria transmission is also high, the burden of severe malarial disease and subsequent mortality in PNG's coastal populations is primarily borne by young children and pregnant women. In PNG, P. vivax is also transmitted intensely and is an important difference with malaria in Africa where P. falciparum accounts for the vast majority of malaria morbidity. P. vivax itself is recognised as a cause of severe illness and mortality, whilst published data on mixed infections with P. vivax are conflicting, with studies describing abrogated, or augmented clinical effects in patients with both species present.