The World Organization for Animal Health (WOAH) announced on Tuesday that France had detected an epidemic of highly virulent H5N1 bird flu among red foxes northeast of Paris as the virus’s spread to mammals sparked widespread concern.

According to a report by WOAH, quoting French officials, three foxes were discovered dead in a natural reserve in Meaux close to where gulls had perished. One of the foxes was taken away and analyzed.

The World Health Organization last month described the bird flu situation as “worrying” due to the recent rise in cases in birds and mammals and that it was reviewing its global risk assessment in light of recent developments including cases of human transmission in Cambodia.

Avian influenza, commonly called bird flu, has been spreading around the world in the past year, killing more than 200 million birds, sending egg prices rocketing and raising concern among governments about human transmission.

The virus infected a cat in France in late December.

It has also been detected in minks in Spain, foxes and otters in Britain, sea lions in Peru and grizzly bears in the United States.