What Is Melioidosis? CDC Says Bacteria That Causes Rare Disease Is Now Endemic Along Gulf Coast

The bacteria, B. pseudomallei, has been historically found in tropical and subtropical climates, but it was recently identified in U.S. soil and water in parts of the Gulf Coast region of Mississippi.

Microscopic View of Human Blood Cells and Burkholderia Mallei Bacteria from a Patient with Glanders - 19th Century
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A new environmental bacteria has been found in U.S. soil and water for the first time, and in some cases it can cause a rare but serious disease called melioidosis, the Centers for Disease Control and Prevention (CDC) said on Wednesday in a press release.

The bacteria, called Burkholderia pseudomallei, has historically been found in more tropical climates, like in South and Southeast Asia, and northern Australia, the CDC said. And while the U.S. typically sees about 12 cases a year, they're in Americans who become infected with the bacteria while traveling.

But, after two people in the Gulf Coast region got sick with melioidosis—one in 2020 and a second in 2022—the CDC and Mississippi State Department of Health ran tests and found that the bacteria was now present in the U.S., too.

"We hadn't thought that the bacteria was in the soil in the United States," Beth Thielen, PhD, MD assistant professor of pediatrics at the University of Minnesota, and adult and pediatric infectious disease physician for M Health Fairview, told Health. "Typically the cases that we would see would be acquired abroad in people who have traveled and traveled back to the US. So the part that is new is finding it here."

Now that this bacteria may be infecting people living in the Gulf Coast region, the CDC is warning medical professionals to consider melioidosis as a possible cause of symptoms like fever, joint pain, chest pain, and more. This is particularly important considering that the disease can be quite severe, especially in people who are immunocompromised.

Though this disease is quite rare, here's what we know about melioidosis, the environmental bacteria that causes it, and how to keep yourself protected.

Newly Endemic to the U.S. Gulf Coast Region

Though these two Mississippi Gulf Coast cases just prompted the CDC to check the soil for the B. pseudomallei bacteria, it's unclear how long it's actually been in the U.S.

"I think it's possible that this [bacteria] could have been there for a while," Dr. Thielen said. "And so it may be that there have been prior exposures that we just weren't aware of because people didn't know to look."

As to how the bacteria got here, that is, for now, also a mystery. As our world becomes increasingly globalized, Dr. Thielen explained that it makes sense that pathogens from different parts of the world would crop up in new places as people travel and engage in trade. Climate change also likely plays a factor.

"We're seeing outbreaks of disease often farther north than we typically have seen in the past," she said. "Environmental changes may also be creating environments that are more conducive to these organisms persisting in parts of the world that we didn't previously see them."

Even as this bacteria seems to move into new soils, Dr. Thielen explained that it's not because they're trying to find human hosts to infect.

"They actually exist quite happily in the environment, and it's really kind of a constellation of bad luck that they happen to end up in the wrong place at the wrong time to make people sick," said Dr. Thielen.

And this is exactly what happens when humans come into contact with the bacteria, which can happen in a number of ways—stirring up soil so that it becomes airborne is one way, Dr. Thielen said. Swimming or coming into contact with muddy water, or even just doing yard work and digging in the dirt without gloves can also put people at risk of melioidosis, the CDC added.

If a person breathes in the contaminated dust, accidentally ingests contaminated water, or comes in contact with either with open sore, the bacteria can get into the body.

On rarer occasions, the bacteria can contaminate products and infect people that way—this was the explanation in 2021 when it was found in aromatherapy products and led to a small outbreak of four U.S. melioidosis cases.

Luckily, unlike some of the viral outbreaks we've seen recently, outside of a laboratory there's no real risk that the bacteria would pass from person to person, Dr. Thielen said.

A Wide Range of Symptoms Treated by Antibiotics

Once a person comes into contact with the B. pseudomallei bacteria, the pathogens continue to grow in whichever area of the body they first enter.

"In the case of pneumonia, it's just the bacteria is growing and making more copies of bacteria in the lungs. It can get into the bloodstream, and from there, it can travel to other parts of the body and can cause bone and joint infections that can affect the brain," Dr. Thielen explained. "The symptoms that people develop really depend on how far the infection has spread and into which organ systems in the body it has spread to."

The CDC names a whole host of symptoms that doctors should look out for as potential signs of melioidosis:

  • Fever
  • Pain or swelling in a specific area of the body
  • Ulceration or abscess
  • Cough or chest pain
  • Headache
  • Weight loss
  • Joint or muscle pain
  • Stomach pain
  • Brain infection or seizures

Because the symptoms of melioidosis are nonspecific, it can sometimes be mistaken for other diseases, the CDC warns. But Dr. Thielen said that proper diagnosis is a key to helping people recover from this severe disease.

"Initially, we don't know what's the cause of [the infection]. So we give them antibiotics that will kind of treat the most common causes," Dr. Thielen explained. "Once we have the diagnosis made, which we do through cultures, then we can target antibiotic therapy. And I think we have good tools to potentially cure this."

Even though we have antibiotic treatments to get rid of melioidosis, it can still be a challenging road to recovery. These antibiotic therapies, Dr. Thielen said, can take months, and because of how deadly the disease can be, people infected will likely need the guidance and advice of an infectious disease doctor who specializes in this kind of work to guide them through their recovery.

How to Stay Safe

Even though melioidosis can be quite a dangerous disease, the CDC's Wednesday warning probably shouldn't be a cause for great alarm, Dr. Thielen said.

Though the B. pseudomallei's range beyond the Mississippi Gulf Coast region is unknown, it needs certain soil and water climates to survive.

"This right now is geographically restricted and that could evolve over time," Dr. Thielen said. "But I'm here in Minnesota—I think the risk that this organism would turn up in the soil in Minnesota is relatively quite low, just because we don't have the same climate. So I think having some awareness of where individual people live and customizing that guidance to a specific region is often quite important."

Even still, if you do live in this region or travel to tropical regions where the bacteria is also endemic, it's smart to avoid putting yourself in situations where you could contract an infection as much as possible, especially if you're someone who is immunocompromised or has other health conditions—like diabetes, cancer, or chronic lung disease—that could make fighting off the bacteria more challenging. Staying away from muddy water and soil, especially without gloves or wound coverings would be a good place to start.

Doctors and the general public alike being aware of melioidosis and this new risk of catching it in the U.S. is probably good enough for now.

"These are pretty small numbers of cases still in the grand scheme of things," Dr. Thielen explained. "It's not among the top worries I think that people should have."

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