What to know about Fusarium graminearum, the biological pathogen allegedly smuggled into the US
Two Chinese nationals were charged with conspiracy and smuggling goods.
The biological pathogen federal authorities accuse two Chinese nationals of smuggling into the U.S. can be concerning for farming communities but was not likely an act of "agroterrorism," according to plant pathology experts.
Two citizens of the People's Republic of China -- Yunqing Jian, 33, and Zunyong Liu, 34 -- were arrested for allegedly bringing a fungus called Fusarium graminearum, a plant pathogen, into the U.S. through the Detroit Metropolitan Airport, according to the U.S. Department of Justice.
Jian received Chinese government funding for her work on this pathogen in China and apparently intended to bring it to a laboratory at the University of Michigan, according to a criminal complaint filed in the Eastern District of Michigan. Liu, Jian's boyfriend, works at a Chinese university where he conducts research on the same pathogen, according to the Justice Department.
Federal prosecutors claim that "scientific literature classifies [the pathogen] as a potential agroterrorism weapon," emphasizing that it is the "of the gravest national security concern."
But the pathogen, while a concern for the agricultural industry, is not necessarily among the most significant threats the industry faces, plant pathology experts told ABC News.
How much risk does Fusarium graminearum pose?
Breakouts of Fusarium graminearum infections already naturally occur in dozens of U.S. states -- basically any state that produces wheat and barley -- and has been established in the U.S. for at least 125 years, Caitlyn Allen, a professor emeritus of plant pathology at the University of Wisconsin-Madison, told ABC News. In addition, the U.S. Department of Agriculture keeps a list of potential agroterrorism agents, and Fusarium graminearum is not on that list, Allen said.
"We're not talking about something that just got imported from China," Allen said. "People should not be freaking out."
Fusarium graminearum is not at the top of the list of concerning pathogens, Gary Bergstrom, a professor emeritus of plant pathology, told ABC News.
"Compared to some other things, I don't think the risk is as high," he said. "It's not zero, but it certainly wouldn't be as much concern as the accidental or otherwise introduction of some serious diseases that we don't have now."
In order to be considered an agroterrorism threat, prosecutors would have to determine that the Fusarium graminearum samples are more aggressive than local strains, perhaps have different mycotoxin production abilities or more resistance to some of the tools used in the U.S., Bergstrom said.
From a research perspective, scientists are "well-versed" in Fusarium graminearum, Paul Esker, a professor of plant pathology and epidemiology at Penn State University, told ABC News.
"It's one of the ones that would be at the lower end of the spectrum for risk," Esker said. "We have the tools to manage it."
Mitigating the threat of the toxic fungus
The biggest group of plant pathogens are fungi, and Fusarium graminearum is in the same general group as yeast, used to make beer or bread, Allen said. The spores of the fungus can infect wheat and barley heads and get into the seeds, where it can multiply.
Agricultural industries have already been meeting to prepare for the threat of Fusarium graminearum, as it usually occurs for wheat and barley at this time of year and for corn later in the year, said Esker, who just attended one such meeting on Tuesday.
The sample confiscated by authorities was likely headed to the lab at the University of Michigan that studies how plants resist disease, Allen said, adding that the USDA spends "quite a bit of money every year" on wheat and barley research.
"One of the most useful ways of solving disease problems on our crops is to breed crops that are resistant to the disease," she said, adding that it eliminates the need for fungicides. "Humans have been doing this for as long as we've been growing plants."
What is head blight?
Although the plant pathogen experts hypothesize that the motive for bringing the sample into the U.S. was not likely nefarious, they caution that the impacts from the fungus can still present a major threat to U.S. crops.
The noxious fungus causes "head blight," a disease of wheat, barley, maize and rice, and is responsible for billions of dollars in economic losses worldwide each year, prosecutors said. The toxins can cause vomiting, liver damage and reproductive defects in humans and livestock, prosectors said.
"Fusarium head blight is already a major threat or a major problem for farmers who are growing wheat and barley in the United States now," Allen said. "It's one of the most important diseases of these crops in terms of current, existing losses."
The economic loss is felt by farmers who can't sell their commodity, Bergstrom said.
In the 1990s, a series of epidemics in the upper Midwest caused a billion-dollar loss over a number of years, he said.
Since then, monitoring programs have been put in place to mitigate the impacts of Fusarium graminearum on crops, Esker said.
The disease is of worldwide importance as well, with documented cases occurring in North and South America, Europe and China, Bergstrom said.
"Plants get sick just like people, and this particular disease that we're talking about, Fusarium, head blight, is a big problem on wheat and barley and some other grains all around the world," Allen said.
The fungus can produce a poison called a mycotoxin or a fungus toxin -- sometimes referred to as the "vomit toxin" because of the negative impacts it can have on the digestive symptoms of humans and animals, Bergstrom said.
The occurrence of Fusarium graminearum is strongly impacted by weather conditions -- especially excess moisture, the experts said.
"If the weather is really dry, I don't expect to see the disease," Esker said.
A case of 'bad judgment?'
Plants pathogens most commonly have been moved around by accident by humans, Allen said.
The USDA maintains a wide set of rules to regulate pathogens, the experts said. In order to be granted an Animal and Plant Health Inspection Service permit from the USDA to bring a foreign strain into the country, researchers must provide background information on the strain, explain the thought process on whether they might represent a threat to local agriculture and human health, and lay out the plan for containing the pathogen, Bergstrom said.
Even strains from other states within the U.S. must undergo the same process, Bergstrom said.
Strains from outside the U.S. undergo more scrutiny, including inspection of the researchers' laboratories, Esker said.
"That is a very sound policy, good science," Bergstrom said.
It is unclear whether Jian and Liu had such permits.
Allen believes the incident is not so much smuggling but a case of "bad judgment" by passionate researchers.
"I'm a biologist, right? But I'm also a biologist who has trained dozens of young scientists over my career," she said.
The Justice Department press release does not detail when the alleged smuggling took place. Jian and Liu were charged with conspiracy, smuggling goods into the United States, false statements and visa fraud, U.S. attorney Jerome F. Gorgon, Jr. announced on Tuesday. Jian's electronics also contained information describing her membership in and loyalty to the Chinese Communist Party, the indictment alleges.
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