Malaria in the United States: Current Status and Travel-Related Cases

Malaria was eliminated from the US in the early 1950s, but it is not eradicated globally and cases continue to occur domestically.

Current Epidemiology

• Annual cases: ~1,500–2,000 reported to CDC (pre-COVID); mostly travel-associated.
• Species: P. falciparum (most severe, ~70%), P. vivax, P. ovale, P. malariae, P. knowlesi.
• Origin: Sub-Saharan Africa (majority), South Asia, Southeast Asia, Latin America, Oceania.
• Local transmission: Rare. 2023: 9 locally acquired cases in FL, TX, MD (Anopheles mosquitoes). First since 2003.

Risk Groups

• Travelers to endemic areas (VFRs — visiting friends/relatives — highest risk due to low prophylaxis use).
• Immigrants/refugees from endemic regions.
• Military, missionaries, aid workers.

Prevention for Travelers

• Chemoprophylaxis (atovaquone-proguanil, doxycycline, mefloquine, tafenoquine) — start before, continue after travel.
• Insect bite avoidance: permethrin-treated clothing, DEET/picaridin repellent, bed nets.
• Standby emergency treatment (if remote).

Clinical Vigilance

• Fever in a traveler returning from endemic area within 1 year = malaria until proven otherwise.
• Rapid diagnostic test (RDT) + thick/thin blood smears.
• Prompt treatment: artemether-lumefantrine (Coartem) for uncomplicated P. falciparum; IV artesunate for severe.

While US malaria risk is low, clinicians must maintain a high index of suspicion for febrile travelers.