The bacteria, Burkholderia pseudomallei, was detected in the Gulf Coast region of Southern Mississippi. Exposure to the bacteria can cause melioidosis, a “rare and serious disease,” according to the C.D.C.; about one in every 4,600 people exposed are found to have the disease, according to a study from 2019. The study also found that about 90,000 people die annually from melioidosis.

“Once well-established in the soil, B. pseudomallei cannot feasibly be removed from the soil,” the C.D.C. wrote in its health advisory. “Public health efforts should focus primarily on improving identification of cases so that appropriate treatment can be administered.”

The samples show that the bacteria has been present in the Mississippi region since at least 2020, when one person in the Gulf Coast region was found to have melioidosis, though it is unclear exactly how long Burkholderia pseudomallei, also known as B. pseudomallei, has been in the area.