The World Health Organization has said it’s still unclear how a man in China got the first known human case of the rare H10N3 bird flu.

What is the rare H10N3 bird flu?

This week, there were reports that a Chinese man became ill with the first case of the H10N3 avian influenza, according to the Deseret News.

  • “This infection is an accidental cross-species transmission,” Chinese authorities said in a statement, The Associated Press reported. “The risk of large-scale transmission is low.”
China reports first H10N3 bird flu cross-species transmission to humans

China’s National Health Commission said the man, who is 41, was hospitalized on April 28. he was later diagnosed with the H10N3 avian influenza virus a month later on May 28, according to Reuters.

  • Officials did not say how he was infected.

How did the man get it?

The World Health Organization told ABC News it was unclear how the man contracted the virus.

  • “The source of the patient’s exposure to the H10N3 virus is not known at this time, and no other cases were found in emergency surveillance among the local population,” the WHO told ABC News.

However, the WHO said the virus doesn’t appear to be spreading between people yet, and there is no clear sign of an outbreak.

How does bird flu spread?

Per the Deseret News, the World Health Organization said avian influenzas can spread through “direct or indirect contact with infected live or dead poultry.” However, the spread of avian flu to humans is considered rare.