Malaria is an illness caused by a parasite that is transmitted by the bite of a female anopheline mosquito. The CLASSIC symptoms are shivers, called rigors or chills, that alternate with high fevers. As the fever drops there is usually extreme sweating, and occasionally diarrhoea can be a prominent symptom. Malaria doesn’t always present with classical symptoms, however, so anyone who gets a fever in a malarious area should be presumed to have the disease and tested accordingly.
In between episodes of fever the patient can appear deceptively well. As malaria does not always cause the classic pattern of symptoms, the golden rule is that any fever could be malaria, in any person who has been in a malaria area any time in the past 12 months.
There are 4 species of parasite that cause malaria. One is potentially rapidly fatal (sometimes referred to as malignant malaria), often resulting in ‘cerebral’ malaria. This is caused by Plasmodium falciparum . Malignant malaria may progress to life-threatening coma or a severe state of shock.
The other form, or benign malaria, may produce recurrent episodes of fever, sometimes over many years. Benign malaria is caused by one of 3 other species – Plasmodium vivax , Plasmodium ovale or Plasmodium malariae . These cause similar symptoms to falciparum malaria, but do not cause brain, or ‘cerebral’ malaria, or shock. Death due to benign forms of malaria is very rare but can occur, usually from trauma to the spleen that causes rapidly fatal loss of blood into the abdomen.
From the bite of a particular species of mosquito (an anopheline mosquito): these mosquitoes bite between dusk and dawn, 2 hours after dusk and 2 hours before dawn are the commonest times. Risk levels for various areas around the world are constantly changing, as are the recommended anti-malaria medications for prevention and treatment.
This is about 10-12 days for malignant malaria (minimum is 7 days) but commonly around 30 days for the benign form. Sometimes the malignant form may not occur until 12 months after the last exposure to infected mosquitoes. The benign form may not appear until 5 years or more after leaving a malaria area.
Malaria is best diagnosed at the time of sweating or fever, by microscopic examination of a blood film. Three to four blood tests collected over a 72 hour period should be taken. Even if still negative, the person could still have malaria and may require further testing to find the organisms in the blood. If there is any doubt it is often best to treat for malaria, as untreated malignant malaria can be rapidly fatal.
Prevention of mosquito bites remains the BEST way to stop malaria. It is recommended that you:
Avoid mosquito bites between dusk and dawn.
Take anti-malaria preventative medicine. This reduces the risk of getting the disease but none of the medications is 100% effective in preventing malaria.
Note that medication should always be used in combination with anti-mosquito measures such as mosquito nets and insect repellent.
Consider other preventative measures, such as:
dressing appropriately in long sleeves and long trousers
using personal insect repellents with DEET
sleep in air-conditioned accommodation or under permethrin-impregnated mosquito nets