KOTA KINABALU: The “monkey malaria” is not adapting to spread between humans yet but there are challenges in preventing its spread due to the wide availability of animal hosts in the country, says a new study.
This is observed in a study report published by researchers from Universiti Malaysia Sabah (UMS), the Health Ministry, the London School of Hygiene and Tropical Medicine, the National University of Singapore and Imperial College London.
They conducted a mathematical analysis of malaria cases reported in Malaysia from 2012 – 2020.
According to the research, the study was conducted following growing concerns of this virus adapting to spread from monkeys to humans via mosquitoes, as there was a rise in the cases of Plasmodium knowlesi (P. knowlesi) in the country.
P. knowlesi is a malaria parasite usually found only in monkeys.
The study showed that increases in cases of monkey malaria in Malaysia is likely to be driven by spill over from macaques to mosquitoes to people.
P. knowlesi is usually carried by macaques and spread to humans when a mosquito bites an infected macaque and then bites a person.
Prof. Kamruddin Ahmed from UMS and a co-author of this study said this analysis showed that the spatial and temporal patterns of P. Knowlesi cases were still consistent with spill over from macaques and there was no evidence of sustained human-mosquito-human transmission.
“Malaysia, through its comprehensive surveillance system, reports the highest number of P. Knowlesi cases globally, with Sabah reporting the highest number of cases in Malaysia.
“While other types of human malaria have been eliminated from Malaysia, thousands of cases of P. Knowlesi are reported every year in Sabah. This can cause severe or fatal disease and remains a critical public health threat,” he said.
Kamruddin said previous evidence shows that the increase in P. Knowlesi cases is strongly linked to deforestation, with people working in logging camps or plantations at forest fringes most at risk.
Dr Kimberly Fornace from London School of Hygiene and Tropical Medicine and the National University of Singapore said this poses major challenges for malaria control in this region.
She said many of the existing malaria control measures, such as sleeping under bed nets and frequent testing for malaria, are not effective when there is a wildlife host.
“This poses a major barrier for malaria elimination in Malaysia and the region,” she added.
The Dean of the Faculty of Medicine and Health Sciences UMS, Professor Dr Mohammad Saffree Jeffree said human cases of P. Knowlesi have been identified across South-East Asia and parts of South Asia.
He said while this study demonstrates there is no evidence of P. Knowlesi currently spreading between humans, it may be possible for this to change in the future.
He said new surveillance and control strategies are urgently needed to address this public health threat and urges the scientific community to continue to support and conduct rigorous research on malaria in efforts towards malaria elimination.
The other co-authors of this study include Hillary Topazian (Imperial College London), Isobel Routledge (Imperial College London), Syafie Asyraf (UMS) and Jenarun Jelip (Ministry of Health Malaysia)
Aside from them, the other co-authors are Kimberly Lindblade (WHO), Pablo Ruiz Cuenca (London School of Hygiene and Tropical Medicine), Samir Bhatt (Imperial College London), Azra Ghani (Imperial College London) and Chris Drakeley (London School of Hygiene and Tropical Medicine).
This research was funded by the World Health Organisation and the Wellcome Trust.
