Malaria, caused by the Plasmodium parasite, is spread by the night-time - dusk to dawn - biting female Anopheles mosquito. The mosquitoes don’t hum and don’t create a welt at the site of the bite, so a person does not know that they have been bitten. This preventable disease affects more than 200 million people worldwide and kills 430,000 people, mostly children. Of the five species of human malaria parasites, Plasmodium falciparum is the most dangerous. The other types of malaria are caused by Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium knowlesi.
Travellers going to malaria endemic areas in Africa, South America, and Asia are at high risk. Persons originally exposed to malaria in endemic areas who go back to their home country to visit friends and relatives are also at risk due to waning immunity. Although partial immunity is developed during years of exposure to parasites, no one becomes fully immune to malaria.
Malaria infections are characterized by fever, headache, muscle ache, chills, fatigue, and vomiting symptoms appearing 3-7 days, weeks, or up to several months after being bitten by an infected mosquito. In cases with P. vivax and P. ovale, relapses may occur weeks or months after being infected. P. falciparum symptoms are more severe and include behavioural changes, confusion, seizures, anemia, respiratory failure, kidney failure, coma and shock. If not treated immediately, P. falciparum malaria can lead to death. Treatment includes artemisinin-combination therapy (ACT) and supportive care of symptoms.
There are a number of options that travellers can take to prevent malaria, including antimalarial medication, using anti-mosquito sprays or lotions, and sleeping under a permethrin-treated bed net. For complete protection guidelines, medication contraindications and alternatives, as well as the geographic distribution of the infection, see IAMAT's: