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What is it?
Malaria is a parasitic disease spread by the female Anopheles mosquito. There are five species of plasmodium (malaria) parasites that can infect humans:
- Falciparum
- Vivax
- Ovale
- Malariae
- Knowlesi
Falciparum is the most serious and causes 95% of malaria deaths.
The different strains can only be distinguished by microscopic examination of the blood.
After being released into the blood stream, the Malaria parasites travel to the liver to begin cycles of reproduction. This process lasts 6-12 days, depending on the species. The infected person will still feel well during this incubation period.
Each Malaria organism grows into a large cell containing thousands of Malaria parasites. These burst, releasing the parasites into the blood stream where they enter red blood cells and again start to multiply. The bursting of the infected red blood cells corresponds with the onset of typical Malaria symptoms – high fever, shivering and sweating. Symptoms can be variable and non-specific and may include headaches, lethargy, muscle pains, abdominal discomfort, diarrhoea, coughing, jaundice (yellowing of the skin), confusion and, in latter stages, possible coma and death.
Malaria symptoms can be difficult to distinguish from influenza or other tropical diseases such as dengue fever, travellers' diarrhoea or typhoid fever. Essentially, any febrile illness which occurs following travel to a malaria-infected area should be considered to be Malaria until proven otherwise. A thorough medical assessment is essential. Symptoms usually occur one to three weeks after infection but can occur up to a year following exposure to the disease.
Malaria may occur even when taking anti-malarial tablets. Anti-malaria medication is not designed to prevent infection, rather to prevent a classic, potentially fatal case of the disease.
While diagnosis is achieved with a blood test, several tests may be required. Treatment may involve a regime of one or more medications administered in a clinical setting. Generally, local doctors and medical clinics practicing in malaria-infected regions are experienced in treating the disease and will recommend an appropriate course of medication.
Where is it found?
Malaria transmission occurs in large areas of tropical countries: Central and South America, Sub-Saharan Africa, the Indian Subcontinent, Southeast Asia, the Middle East and parts of the Pacific.
Transmission is generally higher in rural areas (though urban cases occur in many cities, notably in India and Africa) and during the wet season when mosquito populations increase.
Advice concerning the local malaria risk is essential for all travellers.
Risk to travellers
The risk of Malaria to travellers may vary markedly from one area to another and also varies with season, length of stay, type of accommodation, extent of outdoor activities and other factors. Malaria is usually not a risk at altitudes above 1800 metres but this may vary by country. There are some groups who are at particular risk of getting severe Malaria. Children under five years and pregnant women should consider the risks carefully before travelling to malarial areas.
Prevention of Malaria
Life-threatening cases of Malaria can be prevented by:
- Awareness of malaria-infected areas of the trip.
- Preventing mosquito bites (see separate section)
- Taking anti-malarial medication, when appropriate.