Malaria, a parasite infection transmitted by the nocturnal anopheles mosquito, is a leading cause of illness and death in the tropics. For the non-immune traveller, malaria poses a serious threat because of the rapid development of disease, drug-resistant strains, and the inherent limitation of medications for both prevention and treatment.
Symptoms
Symptoms will not be apparent for a minimum of one week after exposure (incubation period). Malaria can, however, develop weeks or months after leaving a malaria zone. The most consistent symptom is a high fever. Other symptoms include a severe headache and muscle pains, similar to the common “flu.”
If you have travelled to the tropics it is wise to assume that any flu-like illness is malaria for at least 3 months following your return.
Prevention
No preventive treatment offers absolute protection. Drugs alone can no longer be relied upon for absolute malaria prevention.
- Protect yourself from mosquito bites.
- Wear clothing that covers your arms and legs from dusk to dawn.
- Apply mosquito repellent to exposed skin (DEET).
- Reduce outdoor activity in the evenings.
- Screen your bed with a nylon, insecticide-treated net.
- Treat clothing with permethrin, a colourless, odourless, tasteless mosquito toxicant (not licensed for this purpose in Canada)
- Preventive treatment
- Antimalarial drugs are prescribed to reduce the infection rate and the threat of death.
- Atovaquone/proguanil (Malarone) and primaquine act during the incubation (liver) phase of the infection
- Chloroquine, doxycycline, and mefloquine will only act during the phase when the red blood cells become infected.
- Take only as prescribed prior to your arrival in a malaria region, continuing throughout your stay, and following your departure from the area of risk.
- See table for details.
- Antimalarial drugs are prescribed to reduce the infection rate and the threat of death.
| Drug | Adult Dose | Pediatric Dose | Side effects |
|---|---|---|---|
| Atovaquone/proguanil (Malarone) Start 1 day prior to entering malarial area and continue until 7 days after departure |
1 tablet daily | 11-20 kg: 1 pediatric tablet daily > 20 - 30 kg: 2 pediatric tablets daily (as single dose) > 30-40 kg: 3 pediatric tablets daily (as single dose) > 40 kg: 1 adult tablet daily |
Frequent: nausea, vomiting, abdominal pain, diarrhea, mouth ulcers Rare: seizures, rash, hepatitis |
| Chloroquine (Nova-Chloroquine) Note: 1 tablet = 155 mg of base Start 1 week prior to entering malarial area and continue until 4 weeks after departure |
310 mg base once weekly | Once weekly dose < 15 kg: 5 mg base/kg 15 - <20 kg: 1/2 tablet 20-<25 kg: 3/4 tablet 25-<35 kg: 1 tablet 35-50 kg: 1 1/2 tablets > 50 kg: 2 tablets |
Frequent: nausea, headache Occasional: rash Rare: nail and mucous membrane discoloration, hair loss, photophobia, nerve deafness, psychosis, and seizures |
| Doxycycline Start 1 day prior to entering malarial area and continue until 4 weeks after departure |
1 tablet (100 mg) once daily | 2 mg base/kg once daily (max 100 mg daily) | Frequent: Gastrointestinal upset, vaginal yeast infections, photosensitivity Rare: Allergic reactions, esophageal ulceration |
| Mefloquine (Lariam, Apo-Mefloquine) Start at least 1 week (preferably 2-3 weeks) prior to entering malarial area and continue until 4 weeks after departure |
250 mg once weekly | Once weekly: 5-10 kg: 1/8 tablet > 10-20 kg: 1⁄4 tablet > 20-30 kg: 1⁄2 tablet > 30-45 kg: 3⁄4 tablet > 45 kg: 1 tablet |
Frequent: Dizziness, headache, sleep disorders, vivid dreams, nausea Occasional: Confusion, hallucinations, forgetfulness, restlessness, emotional problems (including anxiety, agitation, mood changes) Rare: Suicidal ideations, seizures, psychosis |
| Primaquine* Start at least 1 day prior to entering malarial area and continue until 7 days after departure |
30 mg base daily | 30 mg base daily | Occasional: Gastrointestinal upset Rare: damage to red blood cells in G6PD deficient individuals |
* Can only be prescribed after determining that the G6PD level is normal; prescribing physician will order this test unless previously documented to be normal.
Treatment
- If a fever develops, seek prompt medical attention. It is impossible to make an accurate diagnosis based on symptoms alone. Delays before beginning appropriate therapy can have serious or even fatal consequences.
For More Information
Public Health Agency of Canada:
www.phac-aspc.gc.ca/tmp-pmv/info/malaria-eng.php
World Health Organization:
www.who.int/topics/malaria/en/
Committee to Advise on Tropical Medicine and Travel:
www.phac-aspc.gc.ca/publicat/ccdr-rmtc/09vol35/35s1/index-eng.php
World Health Organization:
malaria.who.int
