The economic burden of zoonoticPlasmodium knowlesimalaria on households in Sabah, Malaysia compared to malaria from human-onlyPlasmodiumspecies
Authors: Abraham Patrick , McMullin Campbell , William Timothy , Rajahram Giri S , Jelip Jenarun , Teo Roddy , Drakeley Chris , Manah Abdul Marsudi , Anstey Nicholas M , Grigg Matthew J , Devine Angela 
Published: May 2024

ABSTRACTBackgroundThe emergence of the zoonotic monkey parasitePlasmodium knowlesias the dominant cause of malaria in Malaysia has disrupted current national WHO elimination goals. Malaysia has free universal access to malaria care; however, out-of-pocket costs are unknown. This study estimated household costs of illness attributable to malaria due toP. knowlesiagainst other non-zoonoticPlasmodiumspecies infections in Sabah, Malaysia.Methodology/Principal FindingsHousehold costs were estimated from patient-level surveys collected from four hospitals between 2013 and 2016. Direct costs including medical and associated travel costs, and indirect costs due to lost productivity were included. One hundred and fifty-two malaria cases were enrolled:P. knowlesi(n=108),P. vivax(n=22),P. falciparum(n=16), andP. malariae(n=6). Costs were inflated to 2022 Malaysian Ringgits and reported in United States dollars (US$). Across all cases, the mean total costs were US$138 (SD=108), with productivity losses accounting for 58% of costs (US$80; SD=73).P. vivaxhad the highest mean total household cost at US$210, followed byP. knowlesi(US$127),P. falciparum(US$126), andP. malariae(US$105). Most patients (80%) experienced direct health costs above 10% of monthly income, with 58 (38%) patients experiencing health spending over 25% of monthly income, consistent with catastrophic health expenditure.Conclusions/SignificanceDespite Malaysia’s free health-system care for malaria, patients and families face other related medical, travel, and indirect costs. Household out-of-pocket costs were driven by productivity losses; primarily attributed to infections in working-aged males in rural agricultural-based occupations. Costs forP. knowlesiwere comparable toP. falciparumand lower thanP. vivax.The higherP. vivaxcosts related to direct health facility costs for repeat monitoring visits given the liver-stage treatment required.AUTHOR SUMMARYKnowlesi malaria is due to infection with a parasite transmitted by mosquitos from monkeys to humans. Most people who are infected work or live near the forest. It is now the major type of malaria affecting humans in Malaysia. The recent increase of knowlesi malaria cases in humans has impacted individuals, families, and health systems in Southeast Asia. Although the region has made substantial progress towards eliminating human-only malaria species, knowlesi malaria threatens elimination targets as traditional control measures do not address the parasite reservoir in monkeys. The economic burden of illness due to knowlesi malaria has not previously been estimated or subsequently compared with other malaria species. We collected data on the cost of illness to households in Sabah, Malaysia, to estimate their related total economic burden. Medical costs and time off work and usual activities were substantial in patients with the four species of malaria diagnosed during the time of this study. This research highlights the financial burden which households face when seeking care for malaria in Malaysia, despite the free treatment provided by the government.