Situation Report: Malaria in the United States

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Cases of Malaria Reported in Florida and Texas

Since the start of the year, eight cases of locally acquired malaria have been diagnosed, including seven in Florida and one in Texas. These are the first locally acquired cases reported in the United States since 2003.

Malaria is a serious and potentially fatal disease spread to humans through the bite of an Anopheles mosquito infected with the malaria parasite. The disease is endemic in many tropical and subtropical regions of the world, and it is a leading cause of illness and death in many of the countries affected by malaria.

What is the Risk in the United States?

Roughly 2,000 cases of malaria are diagnosed in the United States each year. Typically, cases are seen in travelers who were infected while in a country where malaria is endemic. However, it is possible for a mosquito to bite an infected traveler once they are in the U.S. and then spread the disease locally.

While the risk of malaria in the United States is currently low, as people resume travel the number of imported cases will likely increase. More cases of malaria, whether from travel or locally acquired, are cause for concern. 

An outbreak of malaria in the United States could lead to the re-emergence of a disease that was mostly eradicated in the 1950s. That’s because the Anopheles mosquito capable of transmitting malaria parasites to humans is found throughout the eastern United States and particularly in the Southeast.

That risk is elevated by climate change, which is responsible for longer, hotter summers and more intense storms. This is expanding the geographic range and seasonality of the mosquitoes that carry malaria.

Identifying the Symptoms and Diagnosing Malaria

Symptoms of malaria include fever, sweats, chills, headache, muscle aches, tiredness, nausea, and vomiting. If not treated quickly, malaria can cause kidney failure, seizures, mental confusion, coma, and death.

Clinicians should consider malaria in the differential diagnosis if the patient has symptoms of malaria and has traveled to an area where malaria is endemic during the past few months.  Clinical findings should be confirmed by a laboratory test for malaria.

Learn more about malaria symptoms and diagnosis (CDC, https://www.cdc.gov/malaria/diagnosis_treatment/diagnosis.html, Accessed 8/10/2023).

Treating Patients Infected with Malaria

Malaria is a medical emergency. If you suspect a patient has malaria, it’s critical to provide rapid diagnosis and treatment with antimalarial drugs within 24 hours of presentation. Treatment options will depend on the species of Plasmodium (the parasite that causes malaria) and drug susceptibility. The area the patient traveled to can indicate what drugs the parasite may be sensitive to. 

Refer to the CDC guidelines for clinicians on how to assess and treat malaria patients (CDC, https://www.cdc.gov/malaria/diagnosis_treatment/clinicians1.html, Accessed 8/10/2023).

Reporting Cases of Malaria

Malaria is a nationally notifiable disease. Clinicians should report all cases of laboratory-confirmed malaria to their state health department. Refer to the information on the Malaria Case Surveillance Report Form (CDC, https://www.cdc.gov/malaria/report.html, Accessed 8/10/2023) for instructions on how to report a malaria case.

Advice for Health Care Providers

With the expectation that we will see more cases in the U.S., health care providers should be alert for cases of malaria and remind patients to use mosquito repellent, wear long sleeves and pants, especially at dawn and dusk, and dump standing water near their homes.

Malaria should be considered even in patients without a travel history if the symptoms suggest malaria, especially in states where Anopheles mosquitos are active. Co-infection is possible, and diagnosis of another illness should not rule out a malaria infection if symptoms persist.