Malaria

Malaria is a serious disease caused by a parasite. It is primarily found in tropical and subtropical regions and is transmitted to humans through the bites of infected female mosquitoes, mainly of the Anopheles genus. Here are key details about malaria:

Cause

Malaria is caused by parasites of the genus Plasmodium, with four main species infecting humans:

• Plasmodium falciparum: The most deadly form, prevalent in Africa.
• Plasmodium vivax: Common in Asia and South America.
• Plasmodium ovale: Found in West Africa.
• Plasmodium malariae: Occurs worldwide but is less common.

Symptoms

Symptoms usually appear 10-15 days after the mosquito bite and can include:

• High fever
• Chills
• Sweating
• Headache
• Nausea and vomiting
• Muscle pain and fatigue
• Anemia (due to destruction of red blood cells)

Prevention

Preventing malaria involves several strategies:

• Mosquito control: Using insecticide-treated bed nets (ITNs), indoor residual spraying (IRS), and eliminating standing water where mosquitoes breed.
• Prophylactic medication: Taking antimalarial drugs before, during, and after travel to endemic areas.

The Canadian recommendations for the prevention and treatment of malaria outline several drugs used for chemoprophylaxis and treatment. Here is a detailed summary of the key drugs recommended:

1. Atovaquone-Proguanil (Malarone®)

• Prevention: 1 tablet daily with fatty food; start one day before entering the endemic area and continue for 7 days after leaving.
• Advantages: Short post-exposure period, daily dosing.
• Adverse Effects: Nausea, vomiting, abdominal pain, diarrhea, increased transaminases; rare are seizures, rash, mouth ulcers, hepatitis.

2. Doxycycline

• Prevention: 100 mg once daily; start one day before entering the endemic area and continue for 4 weeks after leaving.
• Advantages: Protection against leptospirosis.
• Disadvantages: Daily dosing, photosensitivity.
• Adverse Effects: Gastrointestinal upset, vaginal candidiasis, photosensitivity.

3. Mefloquine

• Prevention: 250 mg once weekly; start 1 week before entering the endemic area and continue for 4 weeks after leaving.
• Advantages: Weekly dosing.
• Disadvantages: Risk of severe neuropsychiatric effects.
• Adverse Effects: Dizziness, headache, sleep disorders, nausea, vomiting, diarrhea; rare are severe psychiatric reactions.

4. Primaquine

• Prevention: 30 mg base daily; start 1 day before entering the endemic area and continue for 7 days after leaving.
• Advantages: Effective for causal prophylaxis.
• Disadvantages: Requires G6PD testing due to risk of hemolysis.
• Adverse Effects: Gastrointestinal upset, hemolysis in G6PD deficiency, methemoglobinemia.

5. Chloroquine

• Prevention: 310 mg base once weekly; start 1 week before entering the endemic area and continue for 4 weeks after leaving.
• Advantages: Long-term safety data.
• Disadvantages: Widespread resistance.
• Adverse Effects: Pruritis, nausea, headache, abdominal pain, diarrhea; rare are retinopathy, psychosis.

6. Hydroxychloroquine (Plaquenil®)

• Prevention: 310 mg base once weekly; start 1 week before entering the endemic area and continue for 4 weeks after leaving.
• Advantages: Long-term safety data.
• Disadvantages: Not effective in regions with chloroquine-resistant malaria.
• Adverse Effects: Nausea, headache, abdominal pain, diarrhea; rare are retinopathy, psychosis, and seizures.