According to The U.S. Centers for Disease Control and Prevention (CDC), two people have died due to a bacteria rarely seen in the United States but is more typically found in tropical regions.

In Georgia, Kansas, Texas, and Minnesota, four patients, including children and adults, were infected with melioidosis, also known as Whitmore’s disease.

The CDC reported that the bacterium Burkholderia pseudomallei, which causes melioidosis, is mostly prevalent in tropical settings like Southeast Asia and northern Australia,

The most recent case was discovered in a post mortem on a patient in late July who had died in a hospital in Georgia, while the first victim died of the illness in Kansas in March.

Two of the patients had risk factors such as cirrhosis and chronic obstructive pulmonary disease, including one who died, but the other two presented with no risk factors.

Although none of the patients had recently traveled abroad, the bacterial strains detected in the four individuals are very similar. They mirror those seen in tropical areas, according to the CDC.

The only other known cases of melioidosis in the U.S. were in the Virgin Islands and Puerto Rico in the Caribbean.

Humans and animals can be contracted melioidosis by direct contact with contaminated water and soil as well as inhalation of dust or water droplets and ingestion of contaminated water or food, says the CDC.

The possibility of transfer from person to person is “extremely low” and the bacteria are not thought to spread through the air or by respiratory droplets.

None of the more than 100 samples taken from the soil, water, and products in and near the patients’ houses tested positive for the bacterium.

“The most likely cause is an imported product (such as a food or drink, personal care or cleaning products or medicine) or an ingredient in one of those types of products,” the CDC said in a statement released Monday, August 9.

“The bacteria normally lives in moist soil and water. However, in rare cases, it has also been found to contaminate wet or moist products in the areas where the bacteria are common”, the agency added.

After being exposed to the infection, melioidosis can take many weeks to emerge. According to the CDC, cough, shortness of breath, exhaustion, nausea, vomiting, sporadic fever, and body rashes are among the symptoms.

Although underlying conditions such as kidney disease, diabetes, liver disease, chronic lung disease, cancer, and excessive alcohol intake might increase the risk, officials say that healthy individuals can still become infected.

In Texas, one of the reported cases of melioidosis involving a 4-year-old girl was just made public. When Lylah Baker became ill in May, and she had no known risk factors for the disease.

Lylah underwent a month in the intensive care unit of Children’s Medical Center Dallas, including being ventilated, and eventually suffered brain damage.

“It was definitely a major surprise to everybody not knowing where [the bacteria] came from,” said Ashley Kennon, the child’s aunt.

The Centers for Disease Control and Prevention has asked clinicians to keep an eye out for bacterial illnesses that do not react to standard antibiotics, including in children and adults who have not been abroad.

165,000 instances of human melioidosis are diagnosed around the world each year, with 89,000 deaths, reports one 2016 study.