This article is in conjunction with the Sarawak-level World Malaria Day 2022
There are many different Plasmodium species that can infect humans and cause malaria – Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale – and these parasites are transmitted via human-mosquito-human.
Director of Malaria Research Centre at Universiti Malaysia Sarawak (UNIMAS) Dr Paul Cliff Simon Divis said infection by Plasmodium falciparum was the deadliest because it can cause coma, which is known as cerebral malaria.
In Malaysia, he said the most common parasite that causes malaria in humans was Plasmodium knowlesi, a parasite commonly found in wild macaques.
Humans are infected by this parasite when infected female mosquitoes transmit the parasite from macaque to humans during blood meal, and this is termed zoonotic malaria.
“Knowlesi malaria accounted for more than 80 per cent of all malaria cases in Malaysia, particularly in Sabah and Sarawak.
“In general, most people have infections when they conduct activities in the farms, in the forests or forest-fringe. Activities include farming, hunting, and logging, where they spend a significant amount of time in the farm/forest and are exposed to the Anopheles mosquitoes,” he told New Sarawak Tribune.
Dr Paul, who is also a member of Malaysian Society of Parasitology and Tropical Medicine (MSPTM) said Anopheles mosquitoes were forest-dwelling mosquitoes, and they usually bred in ponds and vegetation in the farm or forest, unlike Aedes mosquitoes which preferred clear and clean water in containers. Therefore, malaria was not an urban health concern.
Among the classical symptoms included fever, chill and rigor which occur intermittently, and these can occur together with headache, muscle pain, fatigue or nausea. If not treated, the symptoms could progress to severe disease with acute respiratory distress syndrome or kidney injury.
All malaria patients in Malaysia, he said, would be hospitalised for treatment; it could be treated with anti-malaria drugs.
Dr Paul advised the public to wear long sleeve shirts and long pants (less skin exposure), apply insect repellent or use mosquito coil to prevent from getting bitten by Anopheles mosquitoes when working in the farm/plantation or conducting activities in the forest or forest-fringe, as well as sleep in bed nets that are treated with insecticide, and use mosquito coils when spending nights in the farm or forest.
“The public should be aware of the classical symptoms as well (fever, chills and rigors), and get treated immediately at a health clinic or hospital. Inform the doctors of the activities done in the past two weeks.
“Usually patients will recover uneventfully after treatment; of course the patients need to complete the full anti-malaria drug treatment to completely eliminate the parasites in the blood,” he explained.
In case of infection by Plasmodium vivax, Dr Paul said the parasite could stay dormant in the liver for many months or years without showing any symptoms. A drug called primaquine was important to eliminate this dormant stage in the liver if a patient was infected by this parasite.
However, he said, this drug was not required for knowlesi malaria as both chloroquine and artemisinin-combination therapies (ACT) were highly effective for knowlesi malaria
Meanwhile, Universiti Malaysia Sarawak (Unimas) Faculty of Medicine and Health Sciences public health expert Associate Professor Dr Helmy Hazmi said some patients would have severe symptoms or warning signs such as jaundice and dark urine.
“It depends on the types of parasites that infect a person; the appearance of symptoms varies according to the incubation period of the infecting parasites,” he said, adding symptoms could appear as quickly as seven days, ranging up to many years later.
For example, he said, a person infected with Plasmodium knowlesi, symptoms might appear nine to 13 days later while a person infected with Plasmodium falciparum usually showed symptoms within seven to 14 days, but symptoms could also appear six weeks later.
Dr Helmy said among the treatments available and recommended by World Health Organisation (WHO), was a combination of therapy with artemisinin, which was used to overcome and prevent the development of resistant plasmodium.
“Treatment must be carefully and strictly monitored and adhered to, to prevent resistance. We are at substantial risk of getting malaria if we travel to malaria-endemic places or areas for a long time without any precautionary measures.
“However, we can reduce infection by taking precautions such as taking preventive medicines like prophylaxis, wearing appropriate protective clothing, applying mosquito repellents, and using bed nets when travelling to endemic places,” he said.
He advised pregnant women and those with conditions affecting the spleen to avoid travelling to endemic areas.
In the case of Sarawak, he said, the army, loggers or timber workers as well as plantation workers, were at high risks.
“A person with recent travel to malaria-endemic areas should immediately seek treatment if some similar symptoms appear.
“If treated late, a person with malaria can develop complications from severe malaria, for instance, cerebral malaria, anaemia, renal failure and blood clotting problems, among others,” he added.
The Sarawak-level World Malaria Day 2022 and Agenda Nasional Malaysia Sihat (ANMS) 2022 will be held at the Town Square in Kapit today (Aug 6) at 9am.
According to WHO, no single tool that is available today will solve the problem of malaria. WHO called for investments and innovation that bring new vector control approaches, diagnostics, antimalarial medicines and other tools to speed the pace of progress against malaria.
Despite steady advances in lowering the global burden of malaria between 2000 and 2015, progress has slowed or stalled in recent years, particularly in high burden countries in sub-Saharan Africa.
Themed “Harness innovation to reduce the malaria disease burden and save lives”, WHO said an urgent and concerted action would be needed to set the world back on a trajectory towards achieving the 2030 targets of the WHO global malaria strategy.