Malaria Surveillance in Kalimantan Province Bordering Malaysian Borneo: Exploring Community Perceptions, Molecular Prevalence and Drug Resistance Markers

• Main Authors: Diana, Natalia, Paul Cliff Simon, Divis, Ayu Akida, Abdul Rashid
• Format: Thesis
• Language: English; English; English
• Published: Springer Nature 2025
• Subjects: Q Science (General); R Medicine (General)
• Online Access: http://ir.unimas.my/id/eprint/48606/; https://tropmedhealth.biomedcentral.com/articles/10.1186/s41182-025-00757-x; s41182-025-00757-x

Indonesia aspires to eradicate malaria by 2030. Malaria cases have fallen drastically because of national strategic plans and policies, and the Ministry of Health has issued a certification of eradication status to various districts. Over the past 20 years, Kalimantan of the Indonesian Borneo has reported a remarkable decline in malaria cases. This low prevalence, however, contrasts sharply with the zoonotic infection caused by the simian parasite Plasmodium knowlesi that continues to be prevalent in Malaysian Borneo. Given that both regions have a similar epidemiological risk of zoonotic malaria infection and share the same natural habitat, this situation appears incongruous. Therefore, this study was designed to improve our understanding of malaria dispersion along the Kalimantan-Malaysia Borneo border in Indonesia during the malaria elimination phase with an investigation of the distribution of malaria in three Kalimantan provinces that border Malaysian Borneo. To achieve this goal, data collection and blood sampling were conducted in West, East and North Kalimantan provinces that bordering Malaysian Borneo between June 2020 and April 2021. A structured questionnaire was administered to 639 households with respondents aged from 15 to 87 years old (median = 37 years old), consisting of demographic information, knowledge and prevention practices, managing illnesses and attitudes towards contributing factors of zoonotic malaria within the communities. Of these, almost half had primary education level (n=302, 47.6%) and worked in the agricultural sector (n=314, 49.1%). The knowledge in identifying at least two classical symptoms of malaria (n=400, 62.6%) and relating it with mosquito bites (n=407, 63.7%) was remarkable. More than half of the respondents owned bed nets (n=343, 53.7%) and used them in a daily basis. However, most of these bed nets were not treated with insecticide. Indoor residual insecticide spraying by the health authority was not common. It was a common practice that 84.5% of the respondent’s sought treatment at health facilities when suspected of malaria. Regarding the potential of acquiring zoonotic malaria, 36.2% of respondents lived near the forest and 15.8% experienced the presence of monkeys within 500 meters of their house. Additionally, blood samples were taken from 1,125 respondents. aged 1 to 87 years old who attended health facilities and those who lived in risk areas. Nested PCR assays and phylogenetic analysis based on the SSU rRNA genes revealed that the prevalence of malaria was low (0.7%) with four human Plasmodium sp infections (2 P. vivax and 2 P. malariae), three simian Plasmodium infections (2 P. knowlesi and 1 P. inui) and one unidentified species. Moreover, the PkSICAVar-based PCR analysis revealed more P. knowlesi infections in this study site, resulting in a total of 11 single P. knowlesi infections, with 1 mixed infection with P. vivax. Analyses of the drug resistance genes, which were chloroquine resistance-associated multi-drug resistance gene 1 (pvmdr1) and artemisinin resistance-associated kelch-12 propeller domain (pvk12) on P. vivax infections from West Kalimantan showed remarkable point mutations when compared to the reference P. vivax from Central America. All P. vivax infections showed F1076L mutant allele on the pvmdr1, and a consistent non-synonymous mutation S123L in the pvk12 gene. This study confirms the first human infection of zoonotic parasites P. knowlesi and P. inui in West Kalimantan, raising the prospect that simian Plasmodium infection is a substantial public health issue in Kalimantan border, as it is in nearby Malaysian Borneo. These findings emphasise the relevance of employing molecular methods to estimate the prevalence of human and zoonotic malaria along the Kalimantan-Malaysian Borneo border, as well as providing baseline genetic information on antimalarial drug resistance in this region, which may be used to monitor the emergence of malaria parasites that are resistant to antimalarial drugs used in the Kalimantan. However, it is essential to emphasise the significance of continuous malaria surveillance within this community to sustain the current low malaria cases and achieve the country's malaria-free status by 2030.