Once bitten by an infected female Anopheles mosquito, the symptoms of malaria can take 1 to 4 weeks to develop. The parasites that cause malaria can lie dormant in the liver and not produce symptoms for up to a year and sometimes this can cause re-infection of the disease. It is therefore important to see your GP urgently if you develop the symptoms of malaria within a year (especially within 3 months) of returning from a country where there is a malaria risk.