Even as Chinese officials appear to have brought the outbreak of the latest strain of bird flu known as H7N9 under control, experts are warning that virus appears to be mutating.

"It has given us a breather while we look more closely at this virus," William Schaffner, an influenza expert and professor at the Vanderbilt University School of Medicine, said, according to USA Today.

According to World Health Organiztion officials, nearly everyone with the disease contracted it from poultry, an industry that’s been partially shut down since the virus began to spread.

However, based on several cases, the virus appears to be spreading from person to person in situations where people are in very close contact, influenza expert Arnold Monto from the University of Michigan told USA Today.

All told, humans catch H7N9 relatively easily, CTV News reports WHO Assistant Director-General for Health Security Keiji Fukuda as saying, though he has denied that the virus has gained any such ability to move between humans.

According to Schaffner, this may be due to the fact that the strain appears to be “semi-humanized” with a number of genetic changes that allow it to spread more quickly.

Fortunately, however, unlike the pandemic H1N1 strain that struck in 2009, this latest virus seems mostly limited to chickens, whereas the former traveled more quickly throughout Asia via wild birds.

As of May 16, the WHO reported a total of 131 cases and 32 deaths, though health officials warn the death toll may increase yet as many individuals are still hospitalized.

In the meantime, scientists continue to research a vaccine for the virus; however, Monto warns, that because the virus is so different, people would likely need two doses of the vaccine as well as a supplement by an immune-increasing substance.

The outbreak has cost about $6.5 billion to the agricultural sector due to falling prices, consumer confidence and trade, Reuters reports.