MSPTM 2019 Annual Scientific Conference
13 - 14 March 2019
InterContinental Kuala Lumpur

Abstract

Title

HUMAN INFECTIONS WITH THE SIMIAN MALARIA PARASITES, PLASMODIUM CYNOMOLGI AND PLASMODIUM KNOWLESI, IN SARAWAK, MALAYSIAN BORNEO

Type
Oral Presentation
Theme
Scaling Up Efforts in Tropical Disease and Vector Control through Evidence-Based Research
Topic
Malaria

Authors

Main Author
Thamayanthi Nada-Raja1
Presenting Author
Thamayanthi Nada-Raja1
Co-Author
Khamisah A Kadir1
Ting Huey Hu1
Dayang SA Mohamad1
Lolita W Lin1
King Ching Hii2
Paul CS Divis1
Balbir Singh1

Authors' Institution

Department / Institution / Country
Malaria Research Centre, Faculty of Medicine & Health Sciences / Universiti Malaysia Sarawak / Malaysia1
Sarawak State Health Department / Kapit Hospital / Malaysia2
Content
Abstract Content
Human infections with Plasmodium knowlesi, a malaria parasite of long-tailed and pig-tailed macaques, were thought to be extremely rare until a large focus of human infections were reported in the Kapit division of Sarawak, Malaysian Borneo in 2004. Macaques in the Kapit division also harbour P. cynomolgiP. inui, P. simiovale, P. coatneyi, and P. fieldi. Under experimental conditions P. cynomolgi and P. inui can infect humans, and there has been one previous case of a naturally-acquired human infection with P. cynomolgi in Peninsular Malaysia, and recent cases of P. cynomolgi in asymptomatic individuals in Cambodia. The aim of the study was to determine whether human infections with P. cynomolgi and P. inui also occur in Sarawak. DNA extracted from blood samples obtained from malaria patients at Kapit Hospital were screened with nested PCR assays using species-specific primers directed at P. knowlesi, P. cynomolgiP. inui, P. coatneyi and P. fieldi. The screening exercise indicated the presence of mixed P. knowlesi and P. cynomolgi infections in five patients who had parasitaemia ranging from 560 to 35,738 parasites/µl blood. For two of these patients, early trophozoite-infected enlarged erythrocytes with stippling, characteristic of P. cynomolgi, were observed. However, these constituted only 1.5% and 4.7% of the total malaria parasites in the blood. Due to the low proportion of P. cynomolgi, modified protocols had to be applied to amplify, clone and sequence the cytochrome oxidase I gene of Plasmodium from these samples. Phylogenetic analyses of the DNA sequences were able to confirm the presence of P. cynomolgi and P. knowlesi infections in these 5 patients. In conclusion, this is the first report of naturally-acquired human infections with P. cynomolgi in Malaysian Borneo.
Keywords: simian malaria; Plasmodium knowlesi; Plasmodium cynomolgi
Requires Audio or Video system for Presentation?: No