Malaria infection of endemic primates in the Buton Utara Wildlife Sanctuary, Indonesia: Potential for transmission to humans

Background and Aim: Zoonotic malaria is an emerging public health challenge in Indonesia, exacerbated by deforestation and increased interaction between humans and non-human primates (NHPs). This study aimed to estimate malaria prevalence in NHPs within the Buton Utara Wildlife Sanctuary (BUWS) and evaluates the potential risk of zoonotic malaria transmission to nearby human populations. Materials and Methods: Epidemiologic surveys were conducted from 2020 to 2021 in BUWS. Macaca brunnescens, the endemic NHP species, were captured using traps. Blood samples were collected and analyzed through microscopy and molecular techniques to detect Plasmodium species. DNA extraction, mitochondrial DNA barcoding, and polymerase chain reaction were used for species identification and phylogenetic analysis. Human populations residing near BUWS were also screened for malaria via blood smear and DNA analysis. Results: Among the 26 Macaca brunnescens sampled, Plasmodium infections were identified in 50%, including Plasmodium inui, Plasmodium cynomolgi, and Plasmodium simiovale, with one mixed infection. Phylogenetic analyses confirmed the presence of these species. Notably, no Plasmodium knowlesi, a prevalent zoonotic malaria agent in Southeast Asia, was detected. Human malaria screening revealed no zoonotic infections but identified a single case of non-zoonotic malaria linked to travel outside the region. Conclusion: The high prevalence of Plasmodium species in NHPs highlights the potential for zoonotic malaria transmission in BUWS. Although no zoonotic cases were detected among humans, continuous surveillance of NHPs, mosquito vectors, and human populations is essential. Conservation efforts and public health initiatives should focus on mitigating the risks associated with increased human-primate interaction. Keywords: Buton Utara Wildlife Sanctuary, Indonesia, Macaca brunnescens, non-human primates, Plasmodium species, zoonotic malaria.