<img class="styles__noscript__2rw2y" src="https://s.w-x.co/util/image/w/birdflu.jpg?v=at&w=485&h=273" srcset="https://s.w-x.co/util/image/w/birdflu.jpg?v=at&w=485&h=273 400w, https://s.w-x.co/util/image/w/birdflu.jpg?v=ap&w=980&h=551 800w" > Employees of duck farmer Sebastien Pujos prepare to unload a truck with birds into an enclosure as they prepare to slaughter a portion of his 32,000 ducks, in Belloc-Saint-Clamens, southwestern France, on January 6, 2017, during the first wave of a mass bird slaughter after the detection of bird flu. (REMY GABALDA/AFP/Getty Images)

At a Glance For eight years, controversy has surrounded testing of a deadly strain of the bird flu.

Banned in 2014, the research has once again received approval to resume.

Research on a deadly strain of bird flu that was banned in 2014 over safety concerns is set to resume, new reports say.

According to a report published in early February by the journal Science, two labs that conducted controversial lab studies to modify bird flu viruses in order to better understand the interaction between the virus and mammals were banned from continuing their research in 2014 over concerns the testing could make the viruses more dangerous for humans.

Reporters for the magazine discovered that a government panel quietly approved the resumption of the research by the two labs that are based in Wisconsin and the Netherlands, which was confirmed by the New York Times last week.

According to the report, one of the labs at the University of Wisconsin, Madison, will resume testing in a few weeks after researchers received a grant from the National Institutes of Health’s (NIH’s) National Institute of Allergy and Infectious Diseases (NIAID) in Bethesda, Maryland.

The New York Times notes in its report that representatives for the U.S. Department of Health and Human Services confirmed the two labs were given permission to resume testing. However, some scientists raised concerns over the government's lack of transparency in announcing that the research was resuming.

“Details regarding the decision to approve and fund this work should be made transparent,” Thomas Inglesby, director of Center for Health Security of the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, told Science.

“After a deliberative process that cost $1 million for [a consultant’s] external study and consumed countless weeks and months of time for many scientists, we are now being asked to trust a completely opaque process where the outcome is to permit the continuation of dangerous experiments,“ Harvard University epidemiologist Marc Lipsitch told Science.

Fears began back in 2011 when the two labs announced that they had altered the deadly H5N1 variety of bird flu, making it more contagious to ferrets, which are similar to humans in how they catch and spread the virus. Typically, this strain rarely jumps from birds to humans. Scientists fear if the strain does jump more easily to humans and becomes more transmissible, a global pandemic could result.

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The research was halted voluntarily by the two labs in 2011 after concerns were raised, but they once again resumed in 2013 under new U.S. oversight rules. The 2014 ban came after a series of accidents at federal biocontainment labs prompted U.S. officials to "pause" funding for 18 "gain of function" studies, or research that intentionally improves the ability of a pathogen to cause disease to better understand the nature of human-pathogen interactions. This pause in funding included the labs in Wisconsin and the Netherlands.

Richard H. Ebright, a molecular biologist at Rutgers, noted back in 2012 that the deadly virus could pose a significant threat to humans.

"The primary risks are accidental release through accidental infection of a lab worker who then infects others — for which there are many precedents — and deliberate release by a disturbed or disgruntled lab worker, for which the 2001 US anthrax mailings provide a precedent. Bioterrorism and biowarfare also are risks," Ebright said to Scientific American.

This week, Ebright told Science magazine the U.S. government's lack of openness in announcing the resumption of testing, which are being allowed under the same guidelines imposed in 2014, is "disturbing" and "indefensible."

One of the researchers, Yoshihiro Kawaoka of the University of Wisconsin in Madison and the University of Tokyo, says he is happy the team can continue to study the virus.

“We are glad the United States government weighed the risks and benefits … and developed new oversight mechanisms. We know that it does carry risks. We also believe it is important work to protect human health," he said.