Inaugural Lecture

Knowlesi Malaria

Professor Dr. Lau Yee Ling

Since 2009, Prof Lau has established a research team working in medical parasitology. In her inaugural lecture, she shared with us her journey in research associated with the fifth human malaria parasite, Plasmodium knowlesi, which originated from macaque. Although history of P. knowlesi infection in humans is relatively short, its zoonotic nature hinders malaria elimination efforts. To grasp the current perspective of knowlesi malaria, her talk explored different aspects of the disease, including risk factors, diagnosis, treatment, molecular and functional studies.

Like other Plasmodium species, P. knowlesi parasite is transmitted through the bite of female Anopheles mosquitoes, which eventually propagates in humans to cause severe parasitemia. The infection has been an area of interest over the past few years, given its medical importance. The increased incidence was suggested being associated with deforestation and agricultural activities that resulted in the shifts of human settlement and changes in the macaque and mosquito habitat. Besides, the infection is deadly due to the relatively short asexual cycle of P. knowlesi (24-h), where the infection can progress rapidly and cause death. Thus, early diagnosis and prompt treatment are very much needed. 

With the support of research grants, she ventured into malaria diagnostics, given current limitations in differentiating various Plasmodium species, which is important for the choice of treatment. She and her team successfully developed and patented a sensitive, specific, rapid, and easy-to-use molecular diagnostics – loop-mediated isothermal amplification (LAMP), applicable for bedside use. She mentioned that the diagnosis of all five human malaria species remains challenging, and an ideal molecular point-of-care diagnosis is in urgent need. Today, malaria has been managed cautiously, mainly due to drug resistance in treatment. Although the current state of P. knowlesi treatment shows no resistance towards antimalarials, she reiterated that the research on new therapeutic candidates should not be halted as multiple antimalarials resistant Plasmodium sp. strains are emerging in Southeast Asia countries. In line with the effort to combat the challenges, she and her team has also successfully established a model culture of P. knowlesi using human erythrocytes. The breakthrough allows P. knowlesi studies to be conducted in vitro, useful for validation vaccine and drug targets. Additionally, various molecular studies have also been carried out in identifying genetic polymorphisms and molecular markers in P. knowlesi to provide a deeper understanding of its pathophysiology. 

At the end of her talk, she highlighted that malaria control and elimination are greatly impeded by the uncontrollable passage of P. knowlesi in macaque populations, which could lead to human malaria outbreak via zoonotic transmission. It is hoped that the current knowledge on P. knowlesi along with the availability of effective vaccines can better prevent, control, and eliminate the parasites.