Plasmodium knowlesi infection has significant morbidity and mortality impact in Malaysia. This zoonotic malaria parasite is naturally transmissible from macaque to humans in the presence of a competent vector. Human encroachment towards the habitat of macaque has further increased the risk. Stratifying the potential risk of transmission based on the burden of parasite among macaque in a particular area can be the first step for public health intervention. Thus, the study aimed to estimate the prevalence of Plasmodium knowlesi parasite among macaque in Negeri Sembilan and determine its associated factors.
This is a cross-sectional study using a non-probabilistic sampling technique. A total of 212 blood samples from macaques in Negeri Sembilan were collected from seven districts. The Plasmodium spp. infecting the macaques were identified using Real-Time PCR assays on DNA extracted from these blood samples. Statistical tests were done to examine the factors associated with Plasmodium knowlesi infection in the macaque population.
The overall prevalence of Plasmodium knowlesi among macaque in Negeri Sembilan state was 36.3%. Both long-tailed macaque and short-tailed macaque harboured the parasite within them. Co-infection with several malaria parasites were seen in 35.5% of Plasmodium spp positive results. The only significant associated factors in the prevalence of Plasmodium knowlesi were the type of locality (rural vs. urban) and the districts where the macaques were trapped.
The prevalence of Plasmodium knowlesi infection among macaques varied between districts in Negeri Sembilan. The presence of zoonotic malaria parasites among the population of macaque that live in close proximity with the community possesses a potential risk of transmission. Therefore, robust public health advocacy targeting high-risk areas is deemed necessary.