The household economic burden of human-only and zoonotic malaria, compared to other causes of acute febrile illness in Indonesia

Zoonotic malaria caused by infection with the monkey parasite <i>Plasmodium knowlesi</i> has emerged across Southeast Asia, particularly in areas previously close to elimination of non-zoonotic malaria. In Indonesia, some rural and remote areas must now consider strategies which target various <i>Plasmodium</i> species in hard-to-reach populations. Indonesia has mostly subsidised care at local health clinics for patients with malaria and other febrile illnesses; however, patients still face out-of-pocket costs. This study estimated household cost of illness due to malaria and non-malarial febrile illness in North Kalimantan and North Sumatra, Indonesia.Household costs were estimated from individual patients as part of health facility-based cross-sectional surveys in eight health clinics across North Sumatra and North Kalimantan between January 2022 and October 2023. Direct costs due to medical and travel expenses, and indirect costs resulting from productivity losses were included. Overall, 2244 patients were recruited, including 153 (6.8%) malaria-confirmed cases. Five <i>Plasmodium</i> species were identified using validated PCR conducted on all participants: <i>P. vivax</i> (n=97), <i>P. knowlesi</i> (n=35), <i>P. malariae</i> (n=12), <i>P. falciparum</i> (n=3) and <i>P. ovale</i> (n=1), in addition to five mixed infections. Costs were inflated to 2023 Indonesian Rupiah and reported in US dollars (US$). A mean total cost of US$33 (SD=57) was reported for malaria episodes and US$17 for non-malarial fever episodes (SD=38), primarily composed of indirect productivity losses from time away from usual activities (70% and 61% of total cost for patients with malaria and other febrile illnesses, respectively). Overall, 16% of patients with malaria and 11% of patients with other febrile illnesses experienced catastrophic health expenditure from their illness episode.Despite a largely subsidised health system, patients and families face other medical, travel and indirect costs when seeking care for febrile illnesses. These costs need consideration when designing malaria control policies, particularly in near-elimination settings, with few malaria cases among broader febrile illness.