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Infectious Diseases


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What is Malaria?

Malaria is a serious and occasionally fatal disease that is spread by the bite of an infected mosquito. The illness is caused by parasites of the Plasmodium species, which are carried by mosquitoes infected from biting someone who already has the disease.

How is it spread?

Malaria is spread to humans by the bite of a mosquito that is infected with malaria parasites.  The mosquito that spreads malaria is the female Anopheles mosquito and is usually active during the evening, night and early morning (dusk to dawn). While rare, the parasite can also be transmitted by transfusion with infected blood, this risk is very low in countries such as Canada and the United States, particularly since malaria blood tests are performed in blood donated for transfusion.  Other ways that transmission can occur is by shared needle use, or from a mother to her unborn child.

What are the symptoms?

Symptoms of malaria can take from one week to several months to occur (depending on the type of malaria parasite you are infected with). 

The symptoms are often flu-like, including: fever, sweats, chills, headache, abdominal pain, muscle and joint pain, nausea and vomiting, diarrhea and feeling generally unwell. In more severe cases symptoms may include seizures, coma, kidney and respiratory failure, and shock which may lead to death.

What is the treatment for Malaria?

Treatment is dependent on an accurate diagnosis. Once you have been diagnosed your doctor can prescribe the appropriate antimalarial drug to kill the parasite. Almost all malaria can be completely cured. However, even short delays in the diagnosis of malaria can make treatment more difficult and less successful. If you have recently travelled to an area where malaria occurs and you have unexplained fever which started during or after your trip (for up to three months or longer) you should seek medical attention as soon as possible from a health care provider. Be sure to tell your healthcare provider that you have travelled to a region where malaria is present.

How do I protect myself and others?

Check with your doctor before visiting a region that is at high risk for malaria to discuss the use of antimalarial medications. Antimalarial medications decrease your risk of developing symptomatic malaria; however they do not provide 100% protection against the disease. To be effective you will have to begin taking these medications prior to your trip and continue to take them after your trip is over.

It is recommended that travelers to areas where malaria occurs protect themselves from mosquito bites. Wear clothing that reduces the amount of exposed skin; wear light-coloured, long-sleeved, tucked-in shirts, long pants, shoes (not sandals), and a hat. Use insect repellant on exposed skin (of the insect repellants registered in Canada, those containing DEET are the most effective).

Use as directed by the manufacturer paying attention to concentration of DEET, frequency and age of end user. Most repellents containing "natural" products are effective for shorter durations than DEET and for this reason are not considered the preferred products for protecting against mosquito bites (Public Health Agency of Canada).

Sleep in a well screened room and consider sleeping under a bed net, preferably treated with insecticide (e.g., permethrin)

Are there any special concerns about Malaria?

There is no vaccine available against malaria.

Pregnant women, young children and people with a weakened immune system are at particular risk of more serious illness and complications of malaria.

For those who have previously lived in areas where malaria occurs: Unless you are exposed to malaria parasites frequently, you will lose any natural immunity that you may have to the disease. If you move away from your native country, you will lose your immunity within 6 months, and you will be just as much at risk of getting malaria as any other visitor to your native country.

For additional information, please contact the Communicable Disease Team in the Barrie

Office at (705) 721-7520 or a Travel Clinic nearest you.


For travel clinic locations please visit

Malaria – Frequently Asked Questions from the Public Health Agency of Canada is available at



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