Study shows the epidemiological changes in malaria species distribution in Malaysia

Researchers at the Department of Parasitology and Medical Entomology (JPEP) in UKM have revealed the shift on prevalence or incidence of Plasmodium infections from predominantly caused by human malaria parasites to simian malaria parasites, over the last four decades. In a systematic review study published in Malaria Journal, the researchers identified 46 epidemiological studies in Malaysia and linked with parasite species-specific and incidence rates, marking the first time that such study has been linked to disease transition since 1980s.

The researchers have also estimated the performance of major malaria diagnostic methods in Malaysia (i.e. microscopy and PCR).

Photo: Nur Athirah Ahmad Fahmi

“We found that there was a clear trend of decreases of all human malaria species with increasing Plasmodium knowlesi incidence rate throughout the year of sampling period from 1996 to 2017, a disturbing resurgence of parasite that usually causes malaria in monkeys” says Dr Zulkarnain Md Idris, corresponding author and senior lecturer at JPEP.

P. knowlesi is a malaria parasite of monkeys (i.e. long-tailed and pig-tailed macaques) of Southeast Asia that is transmitted by mosquitoes of the Anopheles leucosphyrus group. Humans are frequently infected with this parasite and misdiagnosed as being infected with Plasmodium malariae. Compare to other malaria species, P. knowlesi has the shortest erythrocytic cycle, approximately 24 h. Due to it short asexual cycle, infection with P. knowlesi can rapidly progress into severe malaria than can be fatal.

The study was funded by the Geran Pembiyaan Sepadan (FF-2019-124/1) from the Faculty of Medicine, UKM.

Publication

“Malaria distribution and performance of malaria diagnostic methods in Malaysia (1980-2019): a systematic review” Mohd Amirul Fitri A. Rahim, Mohd Bakhtiar Munajat,  Zulkarnain Md Idris, Malaria Journal, online Nov. 7, 2020, doi: 10.1186/s12936-020-03470-8