A potentially deadly bacterium has unexpectedly been found in US soil for the first time and has been linked to at least two disease cases, prompting the CDC to put out a warning to the public. The CDC’s Health Alert Network has warned that the bacterium Burkholderia pseudomallei has been identified in soil and water samples taken from southern Mississippi.

The two cases, who were diagnosed with the infection in July 2020 and May 2022, were unrelated but lived fairly near to each other in the Gulf Coast region of southern Mississippi. It’s notable that neither had left the US around the time of illness. 

As part of an investigation into the pair, the bacteria was discovered in soil samples taken in June 2022 from the properties and local areas of the two patients.

“It is unclear how long the bacterium has been in the environment prior to 2020 or how widespread the bacterium is in the continental United States,” the CDC said.

It's also uncertain how the bacteria arrived in Mississippi, but genomic sequencing revealed the two patients were infected by the same strain from the Western Hemisphere.

B. pseudomallei can cause a rare and serious disease called melioidosis, also known as Whitmore's disease. 

People can get melioidosis through contact with contaminated soil and water. This includes drinking contaminated water or eating food that's been in contact with contaminated soil. Person-to-person transmission is very rare, but not unheard of.

There are several types of melioidosis depending on where the infection takes hold, each with its own set of symptoms. Because of the somewhat vague nature of the symptoms, it can often be mistaken for other diseases, such as tuberculosis or more common forms of pneumonia.

A localized infection will typically involve pain, swelling, fever, ulceration on the skin, or abscess. It can also affect the respiratory system, causing a cough, chest pain, high fever, and headache. If the infection makes its way into the bloodstream then patients will experience fever, headaches, joint pain, abdominal pain, disorientation, and respiratory distress. Finally, there is disseminated fever infection, which results in fever, weight loss, stomach or chest pain, joint pain, headaches, and seizures. 

The US has seen outbreaks of this infection before. Around 12 melioidosis cases are reported in the US each year, most have occurred in people with recent travel to a country where the bacteria is endemic. Just last year, the CDC confirmed four linked cases – including two deaths – of melioidosis in patients from Georgia, Kansas, Minnesota, and Texas. It turned out that this freak outbreak was sparked by an imported lavender and chamomile aromatherapy spray that was being sold in Walmart.

However, this is the first time the bacteria has been detected in the natural environment of the mainland US. The bacteria are typically found in regions with tropical and subtropical climates around the world, including South and Southeast Asia, northern Australia, parts of Central and South America, the US Virgin Islands, and Puerto Rico.

Unfortunately, now the bacteria has found its way into the soil of the mainland US, it looks like it’s not going anywhere. This is something, the CDC says, that public health bodies in the US need to brace themselves for. 

“Once well-established in the soil, B. pseudomallei cannot feasibly be removed from the soil,” the CDC said. 

“Public health efforts should focus primarily on improving identification of cases so that appropriate treatment can be administered. Melioidosis is now a Nationally Notifiable Disease following a favorable vote at the 2022 [Council of State and Territorial Epidemiologists] conference which should enhance domestic surveillance and public health response,” it added.