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Malaria is caused by a parasite called Plasmodium and is transmitted to humans by the bite of infected female Anopheles mosquitoes.
Malaria is caused by a parasite called Plasmodium. There are 5 species of Plasmodium which infect humans:
Of these, Plasmodium falciparum infection is the most severe and can cause death in up to 10% of cases. It can be rapidly fatal. Pregnant women and children are especially at risk. Other types of malaria are less severe, but still may cause death.
Malaria is a notifiable condition1
The parasite is transmitted to humans by the bite of infected female Anopheles species mosquitoes.
The parasites multiply in the liver and the bloodstream of the infected person. The parasite may be taken up by another mosquito when it bites an infected person. The mosquito is then infected for the duration of its life and can infect other humans when it bites them.
Occasionally malaria is transmitted by blood transfusion. For this reason, people who have travelled to countries where malaria occurs may be deferred from giving blood for a short period. Malaria can also be transmitted from a mother to her fetus.
Malaria occurs in most tropical and sub-tropical areas of the world, including:
Over 600,000 people living in these countries die from malaria each year. Many thousands of tourists also get malaria during their travels to countries where malaria is present. Tourists often get severe illness because they have had no previous exposure to malaria and have no resistance to the disease.
Symptoms of malaria may include:
Plasmodium falciparum may cause cerebral malaria, a serious complication resulting from inflammation of the brain that may cause coma.
Diagnosis is made by a blood test – sometimes it is necessary to repeat the test a number of times, as the parasites can be difficult to detect.
(time between becoming infected and developing symptoms)
Varies with the type:
These periods are approximate and may be longer if the person has been taking drugs taken to prevent infection.
(time during which an infected person can infect others)
Direct person-to-person spread does not occur.
A person remains infectious to mosquitoes as long as the parasites are present in the blood. This may be several years if adequate treatment is not given. Parasites disappear from the blood within a few days of commencing appropriate treatment. Mosquitoes remain infected for life.
Specific antimalarial treatment is available and must always be started as soon as malaria is diagnosed. There is increasing resistance to currently available drugs and treatment should be carried out by an infectious diseases specialist or other expert in the field.
Extensive international programs are undertaken in malarious countries to try to control this disease. For travellers, the following advice is given:
1 – In South Australia the law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.