January 2011

What is Malaria?

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.

How Do People Get Malaria?

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:

  • most of sub-Saharan Africa and limited areas in Northern Africa
  • large areas of Southern Asia, Southeast Asia and some parts of east Asia
  • areas in Central America including the Dominican Republic, Haiti, parts of Mexico and much of South America
  • Papua New Guinea and other small islands in the South Pacific/Oceania region
  • limited areas in the Middle East and Eastern Europe

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.

What Are the Symptoms of Malaria?

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).

How Serious Is Malaria?

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.

How Is Malaria Treated?

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.

How Can Malaria Be Prevented?

Follow the ‘ABCD’ of malaria prevention:

  • Be Aware of malaria risk, symptoms, and how long they take to appear
  • Avoid mosquito Bites
  • Take anti-malarial drugs or “Chemo-prophylaxis“, if appropriate
  • Seek medical help early for Diagnosis, if malaria-like symptoms develop. Advise your health care provider that you have traveled to a region where malaria is present.

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.

More Information on the Prevention of Malaria

Public Health Agency of Canada (PHAC)- “Malaria Frequently asked questions

Adapted from
PHAC – Malaria Travel Health fact sheet
WHO – Malaria fact sheet