Methods for Detection and Identification of Plasmodium Knowlesi: A Review Article

Background: Plasmodium knowlesi is a simian malaria parasite that causes malaria in human also. P. knowlesi detected in human population of many South East Asian countries. It causes life threatening malaria complications. Early detection is very crucial for successful clinical management of knowlesi malaria. Aim: To provide insight into the detection methods used for diagnosis of knowlesi malaria. Method: Detailed reviews of the previous studies on malaria caused by Plasmodium knowlesi with the particular emphasis on diagnostic methods, especially polymerase chain reaction-based molecular detection methods and loop mediated isothermal amplification technique (LAMP) was performed. Result: Due to the morphological similarities between P. knowlesi and other malaria parasites infecting humans, blood film microscopy is not a reliable method for the detection of P. knowlesi. Rapid diagnostic methods based on P. knowlesi-specific antibodies have not been available yet. For half a decade, Nested PCR is in use as the standard method for identification of P. knowlesi. While requiring sophisticated equipment, real-time PCR provides rapid results with higher specificity and sensitivity, so it used in reference laboratories. Loop-mediated isothermal amplification is a promising method for diagnosis of knowlesi malaria in the field. These methods detect small subunit ribosomal RNA as the molecular target. However, recent studies demonstrated the use of multicity, repetitive sequence as the molecular target in single-step PCR detection of P. knowlesi. Conclusion: P. knowlesi misguided for P. malariae by microscopy, which is responsible for high fatalities due to P. knowlesi infections because P. knowlesi produces more severe malaria as compared to P. malariae. Although molecular diagnostic methods are sensitive and specific for P. knowlesi, but these methods are not reliable as compared to gold standard PCR Technique.