Assessment of risk factors associated with Plasmodium knowlesi infection in Sarawak, Malaysia

Objectives: Human cases of Plasmodium knowlesi malaria have significantly increased in recent years, especially in Malaysia. Understanding the risk factors associated with P. knowlesi infections is crucial for improving surveillance and developing effective control strategies. This study sought to identify key risk factors for infection with P. knowlesi in East Malaysia. Methods: From June to August 2019, patients aged ≥7 years with suspected malaria were enrolled at Sibu, Kapit, and Sarikei Hospitals in Sarawak, Malaysia. Blood samples were screened using microscopy and nested polymerase chain reaction to confirm P. knowlesi infection. Demographics, occupation, work environment, medical history, and exposure to animals data were collected through structured questionnaires. Results: Of the 115 patients, 52 (45.2 %) tested positive for P. knowlesi. Patients from Kapit Hospital, a rural area, had twice the odds of testing positive compared to those from urban hospitals. Male gender and living near vegetation, such as plantations, forests, or rice paddies, were also significantly associated with infection. Conclusions: These findings document a high prevalence of P. knowlesi in Sarawak and highlight the need for One Health approaches to control this zoonotic disease, focusing on education, mosquito control, and reducing contact with non-human primates.