Malaria should always be suspected within the first year of return from an infected area and a test done to exclude it as soon as possible. Malaria is one of the most important causes of disease and death in the world. Malaria occurs extensively in tropical and subtropical regions and 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 12 die. For this reason it is important to prevent malaria in those travelling to and from the tropics.
Malignant malaria can kill, but the other forms are much less likely to prove fatal.
There are several stages in the life cycle of the parasite and by and large these are the same for all four types. Malaria is passed on by the Anopheles mosquito biting a person who has malaria parasites in their blood. The parasites develop in the intestine and salivary glands of the mosquito and can be passed on to other people the next time the mosquito bites. Malaria can also be passed on by blood transfusions and the use of infected needles. Plasmodium falciparum is by far the most important malaria parasite in Africa.