Malaria is a potentially fatal tropical disease that is caused by a parasite known as Plasmodium. It is spread through the bite of an infected female mosquito.

The infected person may have feverish attacks, influenza-like symptoms, tiredness, diarrhoea or a whole range of other symptoms. Malaria should always be suspected if these symptoms occur within the first year of return from an infected area; a test should be carried out to exclude the possibility of malaria as soon as possible.

Malaria is one of the leading causes of disease and death in the world. It is estimated that there are 300-500 million new cases every year, with 1.5 to 2.7 million deaths worldwide.

Malaria occurs extensively in tropical and subtropical regions. It used to exist in the UK, but fortunately no longer. Each year 2,000 to 2,500 people return to Britain with malaria, which they have contracted abroad, and, of these, an average of 12 die. For this reason it is important to prevent malaria in those travelling to and from the tropics.

Normally, 10 to 15 days go by between being infected and the onset of the disease, but it may be longer if the patient has taken a preventive medicine.

On a purely practical level, the most malignant (P. falciparum) cases develop within three months of leaving the malaria region, while the forms transmitted by P. vivax and P. ovale may not appear until three years later.

Malaria malariae (a rare, benign form) can survive in man for up to 30 years, luckily without causing much discomfort. This form can also be treated, provided you get the right medication.

The actual attacks of malaria develop when the red blood corpuscles burst, releasing a mass of parasites into the blood. The attacks do not begin until a sufficient number of blood corpuscles have been infected with parasites.