Cases of malaria reported in the U.S. from local mosquitoes for 1st time in 20 years

At least five people in the U.S. have become infected with malaria in the last two months — marking the first time people acquired the disease locally in 20 years.

In Florida, at least four people were infected with malaria, while at least one person reported a case of malaria in Texas.

Malaria “is caused by several species of parasites transmitted by Anopheles mosquitoes.” Those infected with malaria often report experiencing flulike symptoms like nausea, headache fever and chills, and malaria “can lead to serious disease and death when left untreated,” The New York Times reported.

“Malaria is a medical emergency,” the Centers for Disease Control and Prevention alert said.

Health officials have warned doctors to be on the lookout for the infection, especially if they are working in southern states. The five individuals who were diagnosed with the infection have received treatment and “are improving,” according to The Associated Press.

Florida has called for “a mosquito-born illness alert and recommended residents drain standing pools of water, make sure window screens do not have holes in them and use insecticides that contain DEET to repel mosquitoes,” Reuters reported.

The state of Texas has also called for a health alert, telling medical professionals “to routinely obtain travel history to determine if a patient with symptoms of malaria” has spent significant time outside or if they were in a vicinity where they were bitten by mosquitoes, per Reuters.

There are around 2,000 cases of malaria in the U.S. each year, but a large majority of the cases are travelers returning from other countries where malaria is common, per AP News.