What is Malaria?
It is caused by a group of malaria parasites that transmitted by the bite of mosquitoes, namely Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, Plasmodium vivax and Plasmodium knowlesi. The time between the infective bite and the appearance of symptoms varies between 7-30 days. Some may have longer periods up to months or even longer. Symptoms of malaria include intermittent fever, chills, sweating, headache, tiredness, poor appetite, vomiting, diarrhoea, muscle pain and abdominal pain. In typical cases, the fever comes, then subsides for 1-3 days and then comes again in a cyclical pattern. Complications include anaemia, mental confusion, generalized convulsion, circulatory collapse, liver and kidney failure, coma and death if the disease is not treated promptly.
How does it spread?
Malaria is spread by the bite of an infective female Anopheline mosquito. The parasite enters the human body while the infected mosquito is sucking blood. Malaria is not transmitted from person to person. However, malaria can be transmitted through contaminated blood or blood product transfusion, organ transplant, or shared needles or syringes. Malaria may also be transmitted from a mother to her foetus/newborn baby before or during delivery.
How can you prevent it?
Avoiding the bite of mosquito is the first line and the best defense against contracting malaria. You can take the following precautions in preventing mosquito bites:
- Wear long-sleeved, light colour, loose shirts and trousers
- Rest in air-conditioned or well-screened rooms;
- Use aerosol insecticide indoor and use bed nets if sleeping areas are not air-conditioned or screened.
- Use insect repellents containing DEET on exposed skin and clothing. For details about the use of insect repellents, please refer to
Frequently Asked Questions.
- If travelling in endemic rural areas, carry a portable bed net and apply permethrin on it as well as to clothes. Do not apply permethrin on skin.
Malaria infection during pregnancy can have adverse effects on both the mother and the foetus. Therefore, pregnant women should not visit malarious areas unless this is absolutely necessary.
There is no vaccine against malaria for international traveler. If you will travel to areas with risk of malaria infection, consult your doctor beforehand for preventive measures and obtain anti-malarial drugs for prophylaxis if necessary. The commonly used drugs include chloroquine, proguanil, mefloquine, doxycycline and malarone. The choices are based on the particular destinations you are going to visit, the risks as determined by your travelling behaviour and your previous health status. They should only be taken after consulting a doctor. If you decide to take such medication you should start it before the trip, continue throughout the trip and after leaving the malarious area for a period of time according to the instruction of the doctor.
During your visit abroad or after coming back to Hong Kong, if you have symptoms of malaria, seek medical advice immediately and inform the doctor of the places you have visited. Urgent blood tests may be performed and prompt treatment is vital.
How is it treated?
There are effective drugs against malaria but early diagnosis and prompt treatment are crucial. The doctor would prescribe a course of anti-malarial drugs with other supportive measures. The patient should complete the whole course of medication to ensure clearance of the malaria parasites. Malaria parasites resistant to some anti-malarial drugs has been reported in some parts of the world e.g. Cambodia. Travellers should inform doctors of their itinerary so that appropriate medication can be prescribed.
Where is it found?
Malaria is found in tropical and subtropical areas of the world.
Specific information on malaria risk for each country can be found at the World Health Organization website: https://www.who.int/publications/m/item/vaccination-requirements-and-recommendations-for-international-travellers-and-malaria-situation-per-country-2021-edition
For more information issued by the Centre for Health Protection, please refer to the following website:https://www.chp.gov.hk/en/static/24009.html