CDC Issues Health Alert for Malaria in 2 US States

The Centers for Disease Control and Prevention (CDC) headquarters in Atlanta, Ga., in a file image. Tami Chappell via Reuters

The U.S. Centers for Disease Control and Prevention (CDC) issued an alert this week after the spread of malaria occurred within the United States for the first time in 20 years.

Four cases of malaria, caused by the plasmodium parasite, were detected in Florida, according to a CDC health alert issued Monday. Another case was found in Texas, it said.

The disease is caused by a parasite that spreads via mosquito bites, with the largest number of deaths occurring in tropical places—namely sub-Saharan Africa. Symptoms include chills, fever, tiredness, headache, muscle aches, vomiting, diarrhea, and nausea, while anemia and jaundice—a yellowing of the skin and eyes—may also occur.

If left untreated, infected individuals could develop more serious complications and die, officials say.

The CDC alert Monday said that there is “concern for a potential rise in imported malaria cases associated with increased international travel in” the summer of 2023, adding that there is also a “need to plan for rapid access to” intravenous artesunate, a medication that derives from the sweet wormwood plant Artemisia annua. The CDC classifies the drug as “the first-line treatment” for severe cases of malaria in the United States.

The agency further added that it is working with two U.S. health departments to investigate the locally acquired mosquito-transmitted Plasmodium vivax malaria cases,“ adding that there isn’t any evidence to suggest that the Florida and Texas cases ”are related.”

“In Florida,” it said, “four cases within close geographic proximity have been identified, and active surveillance for additional cases is ongoing. Mosquito surveillance and control measures have been implemented in the affected area.”

The file photo of a feeding female Anopheles stephensi mosquito crouching forward and downward on her forelegs on a human skin surface, in the process of obtaining its blood meal through its sharp, needle-like labrum, which it had inserted into its human host. James Gathany/CDC via AP

“In Texas, one case has been identified, and surveillance for additional cases, as well as mosquito surveillance and control, are ongoing,” the health alert said. “All patients have received treatment and are improving.”

It noted that locally transmitted mosquito-borne malaria hasn’t occurred in the United States since 2003 when about eight cases of the illness were found in Palm Beach County, also located in Florida. The alert said that some species of anopheles mosquitos, found in multiple areas around the United States, can transmit the parasitic disease if they feed on an infected individual.

The Texas Department of State Health Services last reported the detection of a local malaria case in a person who had been working outdoors. That individual, it said, had not traveled outside the country or state.

The agency advised residents to protect themselves from mosquito bites by using repellent, wearing long sleeves, and wearing long pants. It also called on people to drain pools and puddles with standing water, which is where mosquitos lay their eggs. People were advised to also keep their gutters clear of debris, cover their trash containers, and change the water in pet dishes.

Before the COVID-19 pandemic, the United States reported about 2,000 malaria cases on average each year, the CDC said. Most of those cases, however, occurred in people to traveled to other countries and was not locally transmitted. Some 5 to 10 people die annually, it said.

An Asian tiger mosquito known to carry malaria. Jack Leonard/Getty Images

Meanwhile, the Florida Department of Health sent out a statewide mosquito-borne illness advisory Monday, saying that four cases were found in Sarasota County.

But, “the risk is higher in areas where local climatic conditions allow the Anopheles mosquito to survive during most of or the entire year and where travelers from malaria-endemic areas are found,” said the CDC. “In addition to routinely considering malaria as a cause of febrile illness among patients with a history of international travel to areas where malaria is transmitted, clinicians should consider a malaria diagnosis in any person with a fever of unknown origin regardless of their travel history.”

The alert also advised doctors and health care officials in areas where locally acquired cases have been reported should use the proper guidance to diagnose and treat those infected individuals. Otherwise, it could lead to a more severe progression of the malarial disease or spread the infection further.

“Malaria is a medical emergency and should be treated accordingly. Patients suspected of having malaria should be urgently evaluated in a facility that is able to provide rapid diagnosis and treatment, within 24 hours of presentation,” the federal health agency wrote.

In Florida, officials also noted that some repellents are not suitable for children, adding that people should avoid applying them to the hands of kids. Parents also should avoid using DEET for children.