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August 29, 2023: Health advisory

Locally acquired malaria cases identified in the United States: Florida, Texas, and Maryland

Actions requested

  • Be aware that locally acquired malaria cases (Plasmodium vivax) have been identified in Florida (7) and Texas (1), and locally acquired Plasmodium falciparum in Maryland (1) within the last 3 months.
  • Consider malaria in any person with a fever of unknown origin, regardless of international travel history, particularly if they have been to the areas with recent locally acquired malaria.
  • Routinely obtain a travel history and consider malaria in a symptomatic person who traveled to an area with malaria in the weeks to months preceding symptom onset.
  • Order microscopic examination of thin and thick blood smears, and a rapid diagnostic test (RDT) if available, to diagnose malaria and confirm species.
    • If blood smears or RDT are positive and species determination is not available, antimalarial treatment effective against chloroquine-resistant P. falciparum must be initiated immediately.
    • Species determination is important because P. vivax and P. ovale can remain dormant in the liver and require additional anti-relapse treatment; failure to treat the dormant hepatic parasites may result in chronic infection with relapsing episodes.
  • Be aware of treatment recommendations for malaria, which vary by species and severity. Please refer to CDC's Malaria Diagnosis and Treatment Guidelines for U.S. Clinicians for specific detailed instructions.
    • Malaria is a medical emergency. If not diagnosed and treated promptly, illness may progress to severe disease, a life-threatening stage, where mental status changes, seizures, renal failure, acute respiratory distress syndrome, and coma may occur. An algorithm for diagnosis and treatment of malaria is available.
    • Artemether-lumefantrine (Coartem®) is the preferred initial treatment of uncomplicated P. falciparum or unknown species of malaria acquired in areas of chloroquine resistance. Atovaquone-proguanil (Malarone®) is another recommended option. P. vivax infections acquired from regions other than Papua New Guinea or Indonesia should initially be treated with chloroquine (or hydroxychloroquine).
    • IV artesunate is the first-line drug for treatment of severe malaria in the United States.
  • Be aware that CDC malaria clinicians are on call 24/7 to provide advice to healthcare providers following infectious disease consultation. Further information can be found online.
  • Discuss travel plans with patients. Prescribe a CDC-recommended malaria chemoprophylaxis regimen and discuss mosquito bite prevention for those traveling to an international area with malaria.
    • Chemoprophylaxis is not needed domestically at this time
  • Report suspected cases of locally acquired malaria to Public Health 206-296-4774 within 3 business days.

Background

  • Be aware that locally acquired malaria cases (Plasmodium vivax) have been identified in Florida (7) and Texas (1), and locally acquired Plasmodium falciparum in Maryland (1) within the last 3 months.
  • Consider malaria in any person with a fever of unknown origin, regardless of international travel history, particularly if they have been to the areas with recent locally acquired malaria.
  • Routinely obtain a travel history and consider malaria in a symptomatic person who traveled to an area with malaria in the weeks to months preceding symptom onset.
  • Order microscopic examination of thin and thick blood smears, and a rapid diagnostic test (RDT) if available, to diagnose malaria and confirm species.
    • If blood smears or RDT are positive and species determination is not available, antimalarial treatment effective against chloroquine-resistant P. falciparum must be initiated immediately.
    • Species determination is important because P. vivax and P. ovale can remain dormant in the liver and require additional anti-relapse treatment; failure to treat the dormant hepatic parasites may result in chronic infection with relapsing episodes.
  • Be aware of treatment recommendations for malaria, which vary by species and severity. Please refer to CDC's Malaria Diagnosis and Treatment Guidelines for U.S. Clinicians for specific detailed instructions.
    • Malaria is a medical emergency. If not diagnosed and treated promptly, illness may progress to severe disease, a life-threatening stage, where mental status changes, seizures, renal failure, acute respiratory distress syndrome, and coma may occur. An algorithm for diagnosis and treatment of malaria is available.
    • Artemether-lumefantrine (Coartem®) is the preferred initial treatment of uncomplicated P. falciparum or unknown species of malaria acquired in areas of chloroquine resistance. Atovaquone-proguanil (Malarone®) is another recommended option. P. vivax infections acquired from regions other than Papua New Guinea or Indonesia should initially be treated with chloroquine (or hydroxychloroquine).
    • IV artesunate is the first-line drug for treatment of severe malaria in the United States.
  • Be aware that CDC malaria clinicians are on call 24/7 to provide advice to healthcare providers following infectious disease consultation. Further information can be found online.
  • Discuss travel plans with patients. Prescribe a CDC-recommended malaria chemoprophylaxis regimen and discuss mosquito bite prevention for those traveling to an international area with malaria.
    • Chemoprophylaxis is not needed domestically at this time
  • Report suspected cases of locally acquired malaria to Public Health 206-296-4774 within 3 business days.
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