An outbreak of pneumonia that has killed one person in China and infected 40 others appears to be linked to a single seafood market in the central city of Wuhan and has not so far spread beyond there, the World Health Organization said Sunday.

The cluster of infections had raised fears of a potential epidemic after China said last week that the virus causing it was a previously unknown type but came from the same family of viruses that caused the SARS and MERS epidemics.

However, the WHO said the outbreak had not spread. The seafood market in Wuhan — a major domestic and international transport hub — is now closed and no cases have been reported elsewhere in China or internationally, it said.