Malaria is an acute flu-like illness caused by one of five species of a parasite called Plasmodium (P). (P. falciparum; P. malariae; P. ovale; P. vivax; and to a lesser extent P. knowlesi). Infection with P. falciparum can be fatal, while infection with P. malariae, P. vivax and P. ovale cause milder illness. P vivax and P. ovale can remain inactive in the liver for many months, which may delay the onset of symptoms for many months or cause relapses of malaria infection. P. knowlesi has recently been recognized as a fifth species causing malaria in people.
Malaria is spread to humans by the bite of a mosquito infected with malaria parasites. The mosquito that spreads malaria is usually active during the evening, night and early morning (dusk to dawn). Malaria transmission occurs in:
On average, about 400 Canadian travelers get infected with malaria each year.
While rare, the malaria parasite can also be transmitted by transfusions with infected blood, by shared needle use, or from a mother to her unborn child.
Symptoms of malaria include fever and other flu-like symptoms such as headache, nausea, vomiting, muscle pain, and malaise. Rigors (severe shakes or muscle spasms) and chills often occur. Acute infection can cause enlargement of the spleen and make the liver tender. Cerebral malaria, which may occur with P. falciparum infection, affects the brain with symptoms such as personality change, confusion, lethargy and seizures. Symptoms can take from one week to several months to occur (depending on the type of malaria parasite).
Malaria can be very serious, depending on the species of malaria parasite causing the infection. P. falciparum leads to the most serious illness and can cause seizures, coma, kidney and respiratory failure and shock, which can lead to death.
If identified early and treated appropriately, almost all malaria can be completely cured. However, even short delays in the diagnosis of malaria can make treatment more difficult and less successful.
Treatment for malaria depends on several factors: the species of malaria parasite causing infection, severity of infection, the age of the infected person, and the pattern of drug resistance to malaria treatment in the area where the infection was acquired.
Follow the ‘ABCD’ of malaria prevention:
Consult a doctor, nurse or health care provider, or visit a travel health clinic at least six weeks before you travel. If you develop a fever during travel to a region where malaria is transmitted or within three months after returning, seek medical advice immediately and advise your physician of your recent travel itinerary.
PHAC – Malaria Travel Health fact sheet
WHO – Malaria fact sheet