Treatment of Plasmodium malariae
Chloroquine remains the treatment of choice for Plasmodium malariae malaria, administered as 25 mg base/kg total dose over 3 days (600 mg base initially, 600 mg at 24 hours, and 300 mg at 48 hours for adults). 1, 2
First-Line Treatment Regimen
Adults
- Total dose: 1,500 mg chloroquine base (25 mg/kg) over 3 days 3, 1, 2
- Day 0: 600 mg base (1,000 mg salt)
- Day 1: 600 mg base (1,000 mg salt) at 24 hours
- Day 2: 300 mg base (500 mg salt) at 48 hours
Children
- Total dose: 25 mg/kg body weight over 3 days 3, 1, 2
- Day 0: 10 mg/kg base
- Day 1: 10 mg/kg base at 24 hours
- Day 2: 5 mg/kg base at 48 hours
- Pediatric dose should never exceed adult dose regardless of weight 2
Pregnant Women
- Use the same adult regimen—chloroquine is safe during pregnancy 3, 1, 4
- Quinine is also safe but requires careful monitoring for hypoglycemia if given intravenously 3
Key Differences from Other Malaria Species
P. malariae does NOT require primaquine for radical cure because it lacks the hypnozoite liver stage that causes relapses in P. vivax and P. ovale 1, 4. This is a critical distinction—primaquine supplementation is unnecessary and should not be routinely added for P. malariae infections.
Chloroquine Resistance Considerations
While chloroquine resistance in P. malariae is extremely rare compared to P. falciparum, isolated cases have been documented in Indonesia 5. If treatment failure occurs:
- Repeat thick blood smear at day 3 of treatment 1
- If parasitemia persists beyond 48-72 hours or symptoms continue beyond 3 days, consider second-line therapy 3, 1
- Alternative options include artemisinin-based combination therapies (artemether-lumefantrine or dihydroartemisinin-piperaquine), though these are primarily registered for P. falciparum 3
Monitoring and Follow-Up
- Administer first chloroquine dose when blood smear is obtained 3, 1
- Instruct patient to return on day 2 for smear results 3
- If smear positive, continue full 3-day course 3
- Obtain repeat blood smear if symptoms persist beyond 3 days to assess parasitemia reduction 3, 1
- Monitor for clinical improvement within 48 hours 1, 6
Supportive Care
- Antipyretics (acetaminophen/paracetamol) for fever control 3
- Frequent tepid water sponging for children with high fevers 3
- Increase fluid intake to prevent dehydration 3
- Oral rehydration solution (ORS) for moderate dehydration 3
Common Pitfalls to Avoid
- Do not add primaquine routinely—P. malariae has no hypnozoite stage and primaquine adds unnecessary risk of hemolysis without benefit 1, 4
- Do not confuse P. malariae with P. vivax or P. ovale, which do require primaquine for radical cure 4, 6
- Ensure proper species identification via thick blood smear before treatment, as management differs significantly between species 3
- In areas without laboratory facilities, if clinical diagnosis is necessary, remember that P. malariae typically causes milder symptoms than P. falciparum but can persist chronically if untreated 3