The U.S. Centers for Disease Control and Prevention (CDC) has confirmed five malaria cases in Florida and Texas, the first time this mosquito-borne illness has been spread inside the country in 20 years.
Public officials have identified four cases in Florida and one in Texas in the past two months, and are continuing to investigate whether more people may be infected, the CDC said in a health advisory on June 26. This is the first time people have caught malaria inside the United States since 2003, when eight locally transmitted cases were identified in Palm Beach County, Florida.
“Malaria is a medical emergency and should be treated accordingly,” the CDC said.
What Are the Symptoms of Malaria?
While there aren’t any specific telltale signs, some common symptoms of malaria are fever, chills, headache, muscle aches, fatigue, nausea, vomiting, and diarrhea, the CDC said. Most people develop symptoms about 10 days to four weeks after being exposed to the virus.
If untreated, severe malaria can lead to a wide range of serious problems, including cognitive impairment, kidney failure, acute respiratory distress, coma, and death, the CDC said. Pregnant people are especially susceptible to severe infections, which can cause miscarriages, preterm births, and stillbirths. Infants, children under 5 years old, and people with HIV or compromised immune systems are also at high risk for severe infections.
Malaria can often be treated with the drug chloroquine, and may also be treated with antibiotics such as quinolones. The exact treatment approach can vary depending on which of four types of malaria people contract and the severity of their illness, according to the CDC.
All five patients with malaria in Florida and Texas are in treatment and on the mend, the CDC said. These cases appear unrelated, but public health officials in Texas and Florida are working to identify any additional cases and take steps to monitor the local mosquito population.
Should I Worry About Malaria While Traveling?
Nearly all malaria cases in the United States are imported and develop in people who have recently traveled to countries where malaria transmission is much more common, often in sub-Saharan Africa and South Asia, the CDC said. Before the COVID-19 pandemic upended travel for many Americans, approximately 2,000 cases of internationally acquired malaria were diagnosed in the United States each year.
Because international travel peaks during the summer months, U.S. malaria cases are typically diagnosed in the summer and early fall, the CDC said. This year, the CDC anticipates travel — and internationally acquired malaria cases — will return to pre-pandemic levels.
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Doctors should consider the possibility of malaria in any person with a fever of unknown origin, regardless of whether they have recently traveled internationally, the CDC said. Clinicians should also be especially vigilant in Florida and Texas, and ask about both domestic and international travel to determine if it’s possible patients were exposed to malaria inside the United States.
To minimize the risk of mosquito-borne malaria, people should use insect repellent, wear long-sleeved shirts and pants, and treat clothes and shoes with permethrin to kill mosquitoes on contact, the CDC recommends. When traveling overseas, people should choose hotels with air conditioning or sleep under a mosquito net to prevent bites. Travelers to malaria-prone regions may also consider taking medication to prevent malaria, such as doxycycline or malarone.