Molecular Surveillance of Zoonotic Malaria Among Indigenous Communities in Malaysia

Molecular investigation of human and non-human primate malaria parasites among indigenous communities in Kelantan, Peninsular Malaysia

Malaysia has succeeded in maintaining zero human malaria status since 2018 up to now. However, zoonotic malaria particularly P. knowlesi infection, has been reported to be increasing in trend, where humans come into contact with Anopheles leucosphyrus–group mosquitoes and the macaque reservoir. Although Malaysian Borneo reported the highest burden of knowlesi malaria, Peninsular Malaysia is also facing increased knowlesi malaria cases in recent years. This worrying trend is mainly due to aggressive land clearing for farming, which increased human-animal exposure, particularly among indigenous communities who are living near forest fringe. As many of these are of public health concern, a team of experts devoted five months conducted a malaria survey among indigenous communities (also known as Orang Asli) in Gua Musang, Kelantan, Malaysia. Due to their remote settlement and dependency on the surrounding forests, indigenous communities are a vulnerable group and likely to predispose to mosquito bites, thus increasing the risk of malaria infection.

The project was led by Dr Zulkarnain Md Idris of Universiti Kebangsaan Malaysia together with Gua Musang District Health Office in Kelantan state. As a first step, the team collected hundreds of dried blood spot samples over five-month period, and then all samples were examined microscopically and further confirmed by molecular tests.

It was found that the prevalence of P. knowlesi infection was low (i.e. 0.4%). Low-level P. knowlesi infection, particularly among indigenous communities, is a significant endemic disease with potential health problems in the country. Submicroscopic and generally asymptomatic P. knowlesi infection could be the major obstacle to the malaria eradication effort in Malaysia. It also could potentially be a source of sustained transmission in the affected community. To limit the further increase of the P. knowlesi infections in Malaysia, highly optimized and sensitive molecular methods are needed to detect the infection effectively. Therefore, a guideline on the importance of submicroscopic P. knowlesi infections, which includes detection and treatment policy, is required to enhance the strategies for knowlesi malaria control in Malaysia.

SEAOHUN 2022 Small Grants

Project team leader: Dr. Zulkarnain Md Idris (Universiti Kebangsaan Malaysia)

Team members: Dr. Muhd Rafiq Mohd Kasri (Ministry of Health Malaysia), Dr. Sherwin Chan (Karolinska Institutet Sweden), Dr. Nor Diyana Dian (Universiti Kebangsaan Malaysia)

- Personal protective equipment, distancing, and group size standards in this photo were consistent with local public health guidance and COVID-19 status in the specific country and time it was taken. This may not reflect best practices for all locations where COVID-19 is still spreading. -