Malaria remains a public health problem in Malaysia, complicated by a monkey malaria species found to infect humans, writes Meera Murugesan.
THE National Strategic Plan for Malaria Elimination aims to eradicate malaria from Peninsular Malaysia by 2015, and from Malaysia Borneo by 2020.
Although the number of reported malaria cases has decreased since the implementation of the malaria control programme, malaria remains a public health problem in Malaysia especially in Sabah, Sarawak and in the interior central regions of Peninsular Malaysia.
This is further complicated by the recent occurrence of a monkey malaria species called Plasmodium knowlesi, which has been found to infect humans.
At the moment, the weapons needed against malaria include an efficient way of detecting the disease, finding out the exact species causing the infection and since malaria is a mosquito-borne disease, an efficient vector control programme.
Professor Dr Lau Yee Ling, head of department of parasitology, Faculty of Medicine, University of Malaya, answers some common questions on malaria.
HOW PREVALENT IS MALARIA IN MALAYSIA?
There are about 4,000 to 5,000 cases of malaria here, mostly zoonotic, every year, where the parasites are transmitted from monkeys to humans through the bite of infected mosquitoes.
Last year, the country also reported 499 cases (imported and introduced from other countries) of the human-to-human type of malaria, and 4,131 cases of zoonotic malaria (macaque to human or Plasmodium knowlesi infection).
WHERE IN MALAYSIA IS THE DISEASE STILL PREVALENT?
Overall, malaria cases are largely reported in Sabah and Sarawak, where a significant proportion of people who stay close to forested areas, thus having a high risk of getting infected.
Forests also serve as ideal breeding sites for anopheles mosquitoes that transmit malaria.
WHAT ARE THE SYMPTOMS COMPARED TO DENGUE?
Malaria and dengue have a few common symptoms such as fever, headache, fatigue, muscle pain and nausea. But other dengue symptoms may also be present such as pain behind the eyes, swollen glands and rashes.
Fever in dengue usually lasts longer (seven days) compared to malaria. Both diseases may result in death.
HOW IS THE DISEASE TREATED?
Malaria can be controlled and treated by anti-malarial drugs if diagnosed early.
For dengue, there’s no specific drug. Instead, treatment is directed towards managing symptoms, and patients with more severe forms of dengue fever are usually hospitalised.
Dengue is a viral infection caused by the bite of a female aedes mosquito whereas malaria is a parasitic infection caused by the bite of a female anopheles mosquito.
The dengue mosquito usually bites a person during the day, approximately two hours after sunrise in the early morning and several hours before sunset at dusk.
Malaria anopheles mosquitoes are “night-biting” mosquitoes and peak around 7pm-9pm.
Malaria mosquitoes mostly favour rural areas. By contrast, aedes thrives in urban areas where there are abundant breeding sites in and around human habitations.
WHY DOES ZOONOTIC MALARIA DESERVE PARTICULAR ATTENTION?
The zoonotic malaria, P. knowlesi, has now been recognised as the fifth malaria species that can naturally infect humans.
Its infection is potentially fatal if treatment is delayed as this parasite species completes its blood stage life cycle in the shortest time among all the human malaria species.
Risk of severe disease from P. knowlesi occurs in six to nine per cent of symptomatic adults.
It’s also the most common species of human malaria in Malaysia.
The commonly used methods such as microscopy and rapid diagnostic tests to diagnose malaria lack the requisite specificity and sensitivity for zoonotic malaria so it is possible that many patients with zoonotic malaria may have been misdiagnosed or underdiagnosed.
ELABORATE ON YOUR TEAM’S DIAGNOSIS METHOD FOR MALARIA.
Affordable and rapid tests of adequate sensitivity and specificity that can diagnose all five human malaria species including P. knowlesi have not been developed.
Our team has combined an innovative molecular technique with lateral flow strip which enables quick malaria diagnosis.
This technique does not require any major equipment, hence, is potentially ideal to be used in resource limited environments.
Results can be obtained by direct visualisation of the band on the strip.
In this way, testing of malaria is as easy as monitoring blood glucose level using the test strip.
The outcome of this project will be the development of Point-of-Care tests that allow rapid and sensitive testing in a primary care setting without the need for trained personnel.
This device will be potentially useful in remote areas.
We hope that it will assist in speedy diagnosis of patients with malaria as well as enhance the quality of life of the population living in high risk areas.