Emergence of the Fifth Human Malaria Parasite, Plasmodium knowlesi: A New Threat to Public Health?

Malaria, a mosquito-borne, protozoan disease is caused by a protozoan parasite of genus Plasmodium (Phylum: Apicomplexan). Four species of malaria parasites are recognized to infect humans. However, a fifth species, Plasmodium knowlesi, has been reported to show potential zoonotic infection in humans as several cases have been testified throughout South East Asia and on the Nicobar and Andaman Islands of India. The most widespread species of macaque in Southeast Asia i.e. long-tailed macaque (Macaca fascicularis) is the natural host for this zoonotic malaria species. Recent case reports have suggested knowlesi malaria are associated with comorbidities which leads to poor treatment outcome. In this review, we have searched the literature from PubMed and Google Scholar and tried to highlight the epidemiology, parasite biology and future challenges regarding this emerging zoonotic infection.