KUALA LUMPUR, April 17 — A surge in cases of “monkey malaria” in Malaysian Borneo has resulted in the use of drones in an effort to contain the spread of the disease.
In a report by The Guardian, the strain of the disease that normally only affects macaques, caused by the parasite Plasmodium knowlesi, is being researched by a team from the London School of Hygiene and Tropical Medicine.
The project, dubbed the Monkey Bar Project, aims to monitor the spread of the disease.
Although bearing a close similarity to a mild form of the disease under the microscope, monkey strain — which accounts for 69 per cent of all human malaria cases in Malaysia — has a high fatality rate due to the parasite’s rapid replication cycle.
Professor in malaria genetics, Cally Roper said the disease was previously very rare but the number of cases has been increasing, with the public at risk when coming into contact with the monkeys.
Eight deaths from the disease were also reported in 2016.
Researchers believe there is a strong link between deforestation and a higher incidence of the disease as monkeys are forced out of their natural habitat towards farmland or to seek out food sources.
Areas which had lost substantial forest cover over the past five years recorded 1.5 to three times as many cases.
“Drones are used to monitor changes in the landscape like the clearing of forests for agriculture, where there is primary or secondary forest or plantations,” said Roper.
“It can then be inferred that forest cover is most conducive to the spread of this form of malaria.”
Drones, besides being cheaper than satellites, are able to provide a more detailed picture of conditions on the ground in areas where the disease is prevalent.
Using a £10,000 (RM55,000) fixed-wing drone and laptop to make 40-minute flights, researchers are able to piece together the data into a high resolution map.
Although the project has been doing this since 2013, the recent addition of thermal imaging capability has allowed researchers to follow the movements of the macaque monkeys.
Kimberly Fornace, a research fellow who has been mapping the loss of forest cover in Sabah, says the process was still being developed.
“We are still optimising the process but the hope is to have a rapid way of estimating how many monkeys are in a particular area without having to wander around the jungle at night looking for them.”
The team has also made use of GPS collars, fixed to individual monkeys, within macaque troops living close to humans and tracked their movements using a drone.
“We’ve used it on several monkeys and on one in particular where we knew there was a large area of land being cleared so we could see where it was moving in response.”
The team’s data is solely on the long-tailed macaques, the most common species of the primate in Sabah, with a majority of them testing positive for P. knowlesi with a prevalence of up to 86 per cent in some areas.
The parasite does not appear to affect the monkeys, which are relatively well-adapted to living close to people.
“[The rise in cases] is a cause for concern because Malaysia has made really huge gains in controlling other forms of malaria and the P. knowlesi strain now makes up the vast majority of cases.
“It is also worrying because what has worked for other strains of malaria such as … doing mass drug administrations — you obviously can’t do with monkeys. There is no way of stopping the transmission,” she added.
Experts hope that the research, using the latest technology, will allow accurate predictions of where outbreaks could occur, enabling a quick response.
The project is due to publish its findings over the past five years later this year, but data gleaned has already had a positive effect.
Officials have used insecticide sprays and distributed bed nets in a more proactive response where trees are being cleared.
This is not the only area where drone technology has helped in the fight against malaria and other infectious diseases.
In Tanzania’s island province of Zanzibar, drones are used to survey malaria hot-spots and identify areas where malaria-carrying mosquitoes are likely to breed such as pools of stagnant water and rice paddies.
Working in partnership with the Zanzibar Malaria Elimination Programme, the effort is aimed at using drone imagery to smartphones to guide insecticide spraying.