Malaria is a common and life-threatening acute febrile illness which occurs in many tropical and subtropical areas of the world. It is transmitted by the bites of infected anopheles mosquitoes.34
Human malaria is caused by four main species of the protozoan parasite Plasmodium: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae. In parts of south east Asia, a fifth malaria is being recognised, Plasmodium knowlesi, a monkey malaria that is being transmitted to humans.
Clinical symptoms include fever and may include chills, headache, muscular aching and weakness, vomiting, cough, diarrhoea and abdominal pain. Because malaria can cause organ failure and death, early diagnosis and appropriate treatment can be life saving. However, the initial symptoms may be mild, and not easily recognised as being due to malaria. Therefore, it is important that the possibility of malaria is considered in all cases of unexplained fever whilst away or after returning from a malarious area, irrespective of preventative measures taken while away.4,34
Transmission34 Malaria parasites are transmitted by various species of mosquitoes, which bite mainly between sunset and sunrise. There is no person-to-person transmission.
Geographical distribution34 Malaria is currently endemic in over 100 countries.
The risk for travellers of contracting malaria is highly variable from country-to-country and even between areas in a country. In many endemic countries of Latin America and the Caribbean, Asia and the Mediterranean region, the main urban areas (but not necessarily the outskirts of towns) are free of malaria transmission. However, malaria can occur in urban areas in Africa and India . There is usually less risk of the disease at altitudes above 1,500 metres, but in favourable climatic conditions it can occur at altitudes up to almost 3,000 metres. The risk of infection may also vary according to the season, being highest at the end of the rainy season.
Risk for travellers34 During the transmission season in malaria-endemic areas, all nonimmune travellers exposed to mosquito bites, especially between dusk and dawn, are at risk of malaria. This includes previously semi-immune travellers who have lost their immunity during stays of 2 years or more in nonendemic areas. Most cases of malaria in travellers occur because of poor compliance with prophylactic drug regimens or use of inappropriate prophylaxis. However, there is no preventative medication that is 100% effective.4
Consult your doctor or a travel medicine clinic before travelling to a malaria-endemic area
Travellers and their advisers should be aware of the four principles of malaria prevention:
- Be aware of the risk, the incubation period, and the main symptoms (see your doctor).
- Avoid being bitten by mosquitoes, especially between dusk and dawn. Please follow precautions in the Insect avoidance section.
- Take antimalarial drugs (Chemoprophylaxis) to suppress infection when appropriate (see your doctor).
- Immediately seek diagnosis and treatment if a fever develops 1 week or more after entering an area where there is a malaria risk, and although malaria can present for up to 3 months after leaving the area (see your doctor), some forms of relapsing malaria can present up to years later.
If you have a fever or are otherwise unwell after being in a malaria area, always let your doctor know that you have been travelling.
(Please read the Disclaimer before using the ABC Guide to Travel Health).
