A deadly new strain of bird flu called H7N9 has killed at least 43 people and infected a total of 134, mainly in western China, according to the World Health Organization. The outbreak in humans has slowed down since the virus was first detected in March, thankfully. But things on the virology front are heating back up because today, 22 scientists from around the world announced their decision to begin new experiments on the virus, which will involve deliberately mutating it in laboratories to create more lethal, drug-resistant and easily-transmissible strains. "Although this A(H7N9) virus outbreak is now under control, the virus (or one with similar properties) could reemerge as winter approaches," the scientists write in a letter explaining their decision, published today in the journals Science and Nature.

Other scientists, though, are extremely concerned that these types of experiments to create super strains of H7N9 have the potential to break out of the lab and cause a pandemic. The backers of the experiments, lead by controversial virologist Ronald Fouchier of the Erasmus Medical Center in Rotterdam, Netherlands, argue they need to move forward and create strains that are more infectious in humans in order to know how to fight probably future mutations of this virus in the wild. As they put it in their letter:

The risk of a pandemic caused by an avian influenza virus exists in nature. As members of the influenza research community, we believe that the avian A(H7N9) virus outbreak requires focused fundamental and applied research conducted by responsible investigators with appropriate facilities and risk-mitigation plans in place.

Many of the scientists that are announcing their work on this research, including Fouchier, also previously worked on creating super strains of another type of bird flu, H1N1, which caused such an alarm among other researchers concerned about accidental outbreak, it resulted in a year-long "moratorium," or pause in research and funding, from 2012 to early 2013. Now these scientists seem to be attempting to preempt anticipated criticism of the similar H7N9 research by releasing a list of the precautions that they'll be taking in their new experiments, including restricting access to only those with high bio-security credentials. The work they did on H1N1 and that they will be doing on H7N9 is called "gain of function" research, because it gives a virus additional capabilities. And the new experiments may be funded in part by the US government, which earlier this year lifted its restrictions on funding such research.

In fact, in order to provide further reassurance, the US Department of Health and Human Services also published a document today stating it would conduct a close review before funding any experiments that are "anticipated to generate H7N9 viruses with increased transmissibility between mammals by respiratory droplets [coughing]." Whether those precautions are enough for critics remains to be seen, but don't hold your breath.