A few genetic tweaks to the bird flu virus that is making people ill or die in China can pave the way for a bigger, more contagious problem.

This is the warning from a new study, revealing that merely three changes could make another human pandemic happen.

The findings come on the heels of federal officials preparing to end a moratorium on laboratory tests that would produce flu viruses with these mutations for scientific research, NPR reported.

Just Small Genetic Tweaks

The H7N9 avian influenza virus has infected over 1,500 people and killed 40 percent of them. But unlike other strains more commonly striking in people, this virus does not spread easily between humans.

However, if the strain mutates in such a way that makes it more easily spread, the bird flu virus could hit the globe, leading to a greater impact. This is because immune systems are yet to be exposed to this kind of flu.

“We’re trying to just understand the virus so that we can be prepared,” biologist Jim Paulson from The Scripps Research Institute said.

What the team did: they experimented with the H7 hemagglutinin (HA) protein, which allows the virus to latch onto cells. They produced the protein with various combinations of mutations in an experimental cell line, since testing in viruses themselves could be risky.

Afterward, they harvested the mutant proteins from the cells and tested the strength of their adherence to human-type and bird-type receptors.

They discovered that three mutations made the fragment more strongly bind to receptors on human cells compared those from avian cells. The triple-mutant H7 hemagglutinins too succeeded in latching onto cells in human tracheal tissue samples.

Based on previous pandemics, this “switch” seems to enable a virus that can spread from person to person.

Prospects For Bird Flu Research

Understanding these mutations, as revealed by the University of Minnesota in a flu scan report, is a beneficial tool for surveillance in both poultry and humans and identifying the first warning signs of a pandemic.

Since the team only looked at one of the virus’s properties, Paulson emphasized that added genetic mutations might prove needed for the virus to turn more contagious in humans. One way to find out would be testing the mutations’ effect in the actual virus.

He and a colleague already proposed to the National Institutes of Health (NIH) to modify the virus, but the moratorium came out in 2014 from the White House, so the proposal was left unreviewed. The said moratorium imposed a stop on federally funded studies that might create more dangerous flu viruses.

But according to Carrie Wolinetz, NIH associate director for science policy, the moratorium will be lifted after a new policy is drafted to improve review of these flu experiments.

The findings were outlined in the journal PLOS Pathogens.

Another study earlier this year, coming from University of South Wales in the UK, found several new flu virus strains in the last decade that may trigger a pandemic. Researchers confirmed the emergence of three novel variant flu strains as well as four novel subtypes of flu viruses in the last five years alone.