What are the prevention and treatment options for malaria?

Malaria: Prevention and Treatment

Prevention Strategies

All travelers to malaria-endemic areas must implement a multi-layered prevention approach combining personal protective measures with appropriate chemoprophylaxis, as no single method provides complete protection. 1

Personal Protection Measures

Mosquito avoidance is critical because Anopheles mosquitoes feed primarily between dusk and dawn. 1

• Remain in well-screened, air-conditioned areas during evening and nighttime hours 1, 2
• Use bed nets treated with permethrin (0.2 g/m² every six months), ensuring the net reaches the floor or is tucked under the mattress 1
• Wear long-sleeved shirts and long trousers when outdoors after sunset 1, 3
• Apply DEET-containing insect repellents (N,N diethylmetatoluamide) sparingly to exposed skin, avoiding high concentrations particularly in children 1, 2
• Spray permethrin on clothing for additional protection 1, 3
• Use pyrethrum-containing flying-insect spray in living areas during evening hours 1, 2

Chemoprophylaxis Selection

The choice of antimalarial prophylaxis depends critically on the geographic region and local drug resistance patterns. 1

For Chloroquine-Sensitive Regions

Chloroquine 300 mg base (500 mg chloroquine phosphate) weekly is the standard prophylaxis for areas without chloroquine resistance, including Central America west of the Panama Canal, Haiti, Dominican Republic, Middle East, and Egypt 1, 2

• Begin 1-2 weeks before travel to ensure adequate blood levels and identify side effects early 1, 2
• Continue weekly during travel and for 4 weeks after leaving the malarious area 1, 2
• Hydroxychloroquine may be substituted for those who cannot tolerate chloroquine 2

For Chloroquine-Resistant Regions

For sub-Saharan Africa and other regions with confirmed chloroquine resistance, combination therapy is essential. 1

• Chloroquine 300 mg base weekly plus proguanil 200 mg daily provides substantial protection in areas with limited to moderate resistance 1
• Atovaquone-proguanil is indicated for prophylaxis in areas where chloroquine resistance has been reported 4
• Mefloquine is an alternative, though neuropsychiatric side effects have been reported 1

Compliance is absolutely essential—most malaria deaths in travelers occur in those who do not comply fully with prophylaxis. 1

Treatment Approaches

Uncomplicated Malaria

For uncomplicated P. falciparum malaria without criteria for severe disease, artemisinin-based combination therapies (ACTs) are first-line treatment. 1, 5

• Artemether-lumefantrine or dihydroartemisinin-piperaquine are the preferred ACTs currently available 1
• Atovaquone-proguanil (1,000 mg/400 mg daily for 3 days) is indicated for treatment of acute, uncomplicated P. falciparum malaria, with 98.7% efficacy in clinical trials 4
• Chloroquine remains an option only if P. falciparum was acquired in a known chloroquine-sensitive region such as Haiti 5

For P. vivax, P. ovale, P. malariae, and P. knowlesi, either artemisinin-based combination therapy or chloroquine for chloroquine-susceptible infections is recommended. 5

• P. vivax and P. ovale require additional treatment with an 8-aminoquinoline to eradicate the liver stage and prevent relapse 5

Severe Malaria

Intravenous artesunate is the first-line therapy for severe malaria and must be initiated immediately. 1, 5, 6

Severe malaria is defined by the presence of any of the following criteria: 1

• Impaired consciousness (Glasgow Coma Scale <11) or unarousable coma 1
• Multiple convulsions (>2 seizures within 24 hours) 1
• Severe anemia (hemoglobin <7 g/dL with parasite count >10,000/mL) 1
• Hypoglycemia (blood glucose <40 mg/dL or 2.2 mmol/L) 1
• Acidosis (pH <7.35 or plasma bicarbonate <15 mmol/L) or hyperlactatemia (venous plasma lactate >5 mmol/L) 1
• Acute renal failure (creatinine >3 mg/dL or oligo-anuria <400 mL/24h) 1
• Pulmonary edema or ARDS (PaO2 <60 mm Hg or SpO2 <92% in ambient air) 1
• Shock (systolic blood pressure <80 mm Hg) 1
• Hyperparasitemia (>2% in non-immune patients from non-endemic regions; >4-5% depending on guideline) 1
• Jaundice (bilirubin >3 mg/dL with parasite count >100,000/mL) 1
• Inability to take oral medication due to repeated vomiting 1

Children, pregnant patients, and people from non-endemic regions are at highest risk of severe malaria. 6

Critical Clinical Considerations

Malaria symptoms can develop as early as 8 days after initial exposure or as late as several months after departure from a malarious area, even after chemoprophylaxis has been terminated. 1, 2

Any febrile traveler who has recently returned from a malarious area must be evaluated urgently for malaria with thick and thin blood smears. 1, 5

• Peripheral blood smears remain the gold standard for diagnosis, though rapid diagnostic tests are available as adjunctive tools 6, 7
• Delay in appropriate therapy can have serious or fatal consequences 1, 2
• The mortality rate from malaria is approximately 0.3% in the US, with severe malaria occurring in approximately 14% of patients 5

Common pitfall: Physicians unfamiliar with malaria may misdiagnose it as influenza, gastroenteritis, dengue, or viral hepatitis due to nonspecific symptoms. 8 Malaria is not a clinical diagnosis—microscopic examination of blood films is mandatory. 8

No prophylaxis provides 100% protection, and travelers must understand that prompt medical evaluation is essential if symptoms develop. 1, 2