Malaria
SYMPTOMS AND SIGNS
Malaria should be suspected in any patient from an endemic country (see Map1 and Map2) with fever (usually cyclical but not necessarily)* or a combination of the following symptoms:
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* Remember that not all patients with malaria present with fever. Family doctors should maintain a high index of suspicion for malaria when refugee patients present with non-specific illness symptoms (e.g. flu-like symptoms).
Also look for signs of anemia and splenomegaly on exam, in addition to any alarming sign such as convulsion, altered consciousness, shock, jaundice, hemoglobinuria and hypoglycemia.
Patients who have recently arrived (in the last 3 months) from an endemic country are especially at risk of symptomatic malaria (mainly Plasmodium falciparum), but P. vivax and ovale infections can sometimes manifest months and even years after exposure.
>> For country-specific malaria information, refer to the following resources:
- Fit for Travel - List of Countries. Each malaria-endemic country contains a malaria map detailing the areas at risk in the country.
- Centers for Disease Control and Prevention (CDC) - Malaria Information and Prophylaxis, by Country. Includes a list of the different malaria species found in each country.
TESTING
If malaria is suspected, testing should be ordered as soon as possible. If testing cannot be performed in the community on the same day or if rapid follow-up of the results is not possible (e.g. end of the day or before the weekend), the patient should be sent to the Emergency Department to be tested there.
When testing for malaria, most Canadian laboratories use a combination of thick and thin blood smears and a rapid diagnostic test. Nucleic acid amplification tests are also used in some places.
If the patient has fever and malaria is ruled out with appropriate testing, other infectious diseases (such as dengue, chikungunya, enteric fever, influenza, hepatitis, liver abscess, brucellosis, meningitis, pneumonia, tuberculosis and leptospirosis) should then be considered depending on the other associated symptoms (rash, abdominal pain, diarrhea, cough, etc.). This is however outside the scope of the present guidelines, and an Infectious Diseases referral should be considered in these cases.
>> For an approach to fever in the returned traveler (or refugee), refer to the following guidelines:
- Committee to Advise on Tropical Medicine and Travel (CATMAT) guidelines
- Centers for Disease Control and Prevention (CDC) guidelines
TREATMENT
The role of the community family physician is to be alert for potential malaria symptoms and diagnose the infection quickly. Any diagnosed case of Plasmodium falciparum infection should be urgently referred to the Emergency Department. This is because even uncomplicated cases of P. falciparum can rapidly evolve into severe malaria and thus treatment should be initiated under observation as soon as possible.
While uncomplicated cases of non-falciparum malaria (P. vivax, ovale, malariae, knowlesi) can be treated in the community, this requires special expertise, and a consultation with an Infectious Diseases specialist is recommended. If primaquine is used to treat a P. vivax or ovale infection, make sure to rule out G6PD deficiency prior to initiating treatment (see G6PD Deficiency).
>> Refer to the Canadian Recommendations for the Prevention and Treatment of Malaria by the Committee to Advise on Tropical Medicine and Travel (CATMAT) for more information on the diagnosis and treatment of malaria, including the criteria for severe malaria.