Not 'just' a fever - understanding the real threat of malaria

MALARIA remains a major global public health challenge, with unacceptably high levels of disease and death still being reported. In 2023 alone, the World Health Organisation (WHO) estimated 263 million malaria cases and 597,000 related deaths worldwide.

Despite this alarming global trend, Malaysia has successfully maintained zero locally transmitted human malaria cases for six consecutive years from 2018 to 2023. However, the country continues to face the threat of malaria through imported cases from endemic regions, as well as the rising concern of zoonotic malaria.

For instance, in 2022, 89.2 per cent of the 404 malaria cases reported in Malaysia were zoonotic, while the remaining cases were classified as imported.

Understanding the Spread of Malaria

Malaria is caused by protozoan parasites of the genus Plasmodium, which infect human red blood cells. These parasites are transmitted through the bites of female Anopheles mosquitoes, which are vectors that require a blood meal before they can develop eggs.

Once transmitted through a mosquito bite, Plasmodium parasites enter the bloodstream and travel to the liver, where they mature before infecting red blood cells. At this stage, an infected person begins to experience symptoms of malaria.

There are four Plasmodium species commonly known to cause malaria in humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae.

In recent years, an increasing number of human malaria cases have been attributed to Plasmodium knowlesi, a species that primarily infects primates such as monkeys. Plasmodium knowlesi cases are predominantly reported in forested regions of Southeast Asia and the Pacific, particularly on the island of Borneo.

In Malaysia, severe malaria cases are most commonly caused by Plasmodium knowlesi, followed by Plasmodium falciparum.

One of the contributing factors to the rise in malaria transmission is the proliferation of mosquito breeding sites, often due to poor drainage systems, stagnant water, and unhygienic environmental conditions.

Additionally, travelling to or residing in malaria-endemic regions, including tropical and subtropical areas also increases the risk of infection.

In addition, malaria can also be spread through rare and less common methods, such as mother-to-child transmission during pregnancy, blood transfusions and sharing of contaminated needles used for drug injection.

Symptoms of Malaria

Malaria symptoms typically begin with the 'cold stage', where the infected person experiences visible chills and shivering.

This is followed by the 'hot stage', in which the person develops a high fever (above 40°C) and feels extremely ill and restless. Vomiting may also occur during this stage.

The third and final stage is the 'sweating stage', where the infected person sweats profusely as the fever gradually subsides. The entire process can last between six to ten hours. Without treatment, the cycle of 'cold stage', followed by 'hot stage' and 'sweating stage', will repeat itself.

Other symptoms of malaria infection include headache, fatigue, general discomfort, muscle and joint aches, and abdominal discomfort.

How is Malaria Treated?

The treatment of malaria infection is generally classified into two categories based on severity, which are uncomplicated malaria and severe or complicated malaria, as well as the specific Plasmodium species causing the infection.

The WHO recommends Artemisinin-based Combination Therapy (ACT) as the standard treatment for malaria. The choice of combination therapy is determined by several factors following a thorough medical assessment by a doctor.

In addition, the history of resistance to certain medicines is also an important consideration when selecting the most appropriate treatment.

• Uncomplicated malaria:

An additional oral antimalarial drug, primaquine, is required and needs to be taken for 14 days for malaria infections caused by Plasmodium vivax or Plasmodium ovale. This addition is necessary because infections by these two parasite species can remain dormant in the liver and may cause a relapse if not properly treated.

• Severe and complicated malaria:

The patient’s condition and response to treatment will be closely monitored throughout the hospital stay. Additional supportive care, such as intravenous fluids, may be necessary if the patient experiences persistent vomiting.

Once the severity of the illness has subsided and the patient’s condition stabilises, the antimalarial treatment may be switched to an oral formulation.

Preventive Strategies

Malaria is a preventable disease, and preventive measures are strongly recommended for anyone high-risk at contracting malaria. High-risk groups include travellers or visitors to endemic regions, military personnel, loggers, rubber tappers and workers involved in dam construction or plantation work.

The risk of contracting malaria varies widely depending on factors such as the intensity of transmission in the area, duration of exposure, and adherence to preventive practices. Special precautions should be taken for vulnerable individuals such as pregnant women and those with severe splenic dysfunction, who are strongly advised to avoid travel to malaria-endemic regions.

Preventing malaria requires a combination of personal protective strategies and when necessary, preventive medicines.

Individuals planning to travel to areas known for malaria transmission should consult a healthcare professional. A thorough medical assessment is important to determine the most suitable antimalarial medicines to be taken as a prevention.

These medicines may need to be started before travel, continued during the stay, and for a period after leaving the area. However, a preventive regimen is only effective if the full prescribed course is followed diligently.

In addition to medicines, avoiding mosquito bites is equally essential.

Effective strategies include applying insect repellents containing diethyltoluamide (DEET) in concentrations of 20-50 per cent, wearing long-sleeved shirts and pants, and sleeping in mosquito-free environments or under insecticide-treated bed nets.

DEET-based repellents are generally safe for adults and children above two months of age. Low-concentration products are recommended and should be applied sparingly.

Equally important, eliminating stagnant water and maintaining a clean environment play a significant role in reducing mosquito breeding and limiting malaria transmission. Community-wide preventive measures are just as vital as individual ones.

On top of that, if an individual begins to show symptoms such as fever, chills, or fatigue, prompt medical evaluation is crucial. Early diagnosis and timely treatment help prevent complications and reduce the risk of severe illness.

In conclusion, while Malaysia has made commendable progress in controlling malaria, the ongoing risk posed by imported and zoonotic cases underscores the need for continued vigilance. Public awareness, early diagnosis, appropriate treatment, and sustained preventive efforts remain the backbone of malaria control strategies.

If there are any inquiries regarding medicines, please call the National Pharmacy Call Centre (NPCC) at the toll-free number 1-800-88-6722 during weekdays from 8am to 5pm, except on public holidays.

Prepared by Ng Xiang Yi, Pharmacist at Hospital Queen Elizabeth, Sabah. She can be contacted at [email protected].