healthHealth and Medicine

A Dangerous Tropical Disease Made Its Way Into Three US States, And The CDC Doesn't Know How


Dr. Katie Spalding


Dr. Katie Spalding

Freelance Writer

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer


It’s unlikely these outbreaks are the first signs of B. pseudomallei becoming endemic to the US. Image credit: TheBlueHydrangea/

There’s a worrying medical mystery unfolding across the USA. In Kansas, Minnesota, and Texas, a rare and potentially fatal disease has left two people hospitalized – and one dead.

The source of the infection? Nobody knows.


For many of us, the only place we’ve heard somebody say the word “melioidosis” is in a rerun of House, MD. There are two reasons for that: first of all, it’s rare outside of tropical or subtropical areas like Southeast Asia or northern Australia. And second of all, because melioidosis is exactly the kind of disease that would end up in front of a doctor like House – the symptoms are non-specific, it’s easily confused for other diseases like pneumonia or tuberculosis, and by the time a patient starts showing symptoms they already have up to a 50 percent chance of losing their lives to it.

In the three cases found by the CDC, there’s another mystery: how the patients contracted the infection in the first place. Burkholderia pseudomallei, the bacteria that causes melioidosis, can’t normally be passed from person to person and has never been found “wild” within the United States. However, none of the three patients have a recent history of leaving the country.

“Most cases [of melioidosis] in the United States occur in persons returning from a country where the disease is endemic,” explained a CDC health advisory, issued on Wednesday. “These three cases are unusual because no recent travel outside the United States has been identified.”

The first patient was identified in March and died less than two weeks after hospitalization. The CDC noted in its report that he had several risk factors for the disease, including lung issues and cirrhosis.


The other two patients, a woman and a child, survived the disease – though one remains hospitalized. The other has been moved to a transitional care unit to continue recovery.

While the origin of the three melioidosis cases remains a mystery, the CDC has ruled out some of the most outlandish – and concerning – scenarios. For instance, genomic analysis suggests it’s unlikely these outbreaks are the first signs of B. pseudomallei becoming endemic to the US. And we’re probably not looking at the first victims of some terrifying new germ warfare either: “At this time, there is no evidence to suggest the cases under investigation are the result of a biological attack,” said William Bower, epidemiology team lead at the Bacterial Special Pathogens Branch of the CDC, in an interview with Gizmodo.

The mortality rate of melioidosis has led the CDC to list it as a tier one select agent – the same ranking as Ebola and smallpox. This makes the concern that it could be used as a bioweapon a priority for the Department of Defense, who only this week awarded researchers at the University of Hawai’i at Mānoa a $3 million grant to fund the development of a vaccine against the disease.

But for now, the CDC says that the risk to the public is low. This isn’t the first time cases have turned up in the US with no obvious origin, and the advisory has told healthcare workers to “Consider melioidosis in patients with a compatible illness even if they do not have a travel history to a disease-endemic country.”


Hopefully, the source will be found, however – and before anybody else is infected.

“Genomic analysis of the strains suggests a common source, such as an imported product or animal,” the CDC warned. “However, that source has not been positively identified to date.”



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