Identification of malaria parasites and molecular characterisation of Plasmodium Knowlesi from fatal human infections

• Main Author: Sunita Sara, Gill Shamsul
• Format: Thesis
• Language: English
• Published: Universiti Malaysia Sarawak (UNIMAS) 2009
• Subjects: RC Internal medicine
• Online Access: http://ir.unimas.my/id/eprint/31747/1/Sunita%20%28ft%29.pdf; http://ir.unimas.my/id/eprint/31747/

Until recently, only four species of Plasmodium parasites were thought to be the aetiological agents for human malaria. However, recent nested polymerase chain reaction (PCR) based studies have shown that P. knowlesi, a parasite that naturally infects macaques is responsible for a significant number of human malaria cases in Southeast Asia. Since P. knowlesi blood forms are identical to P. malariae and the early trophozoites are identical to P. falciparum, most of these cases were diagnosed by microscopy as P. malariae. Plasmodium knowlesi infections are potentially fatal and four fatal cases occurring in Sarawak between 2004 and 2005 were found to have been caused by P. knowlesi using nested PCR assays. According to the Sarawak State Health Department, between 1999 and 2005, there were 35 fatal malaria cases reported in Sarawak with 29 of them due to P jalciparum infections, three to P. vivax, three to P. malariae and one due to mixed P. falciparum-P. vivax infection. The aims of the study were therefore to identify the species of Plasmodium from the 35 fatal malaria cases reported in Sarawak from 1999 to 2005 by morphological and molecular methods. The purpose was to determine whether the microscopy results were accurate and whether there have been any other fatalities due to P. knowlesi prior to 2005 among these 35 fatal cases. Archived blood films which consisted of thin and thick blood smears' from the 35 fatal malaria cases were obtained from the Sarawak State Health Department.