Authorities are investigating the source of the mainland's 17th human bird flu case, but an official from the patient's hometown in Hubei province said he could have contracted the disease elsewhere.
Lai Mingliang, 21, is in a critical condition in hospital in the provincial capital, Wuhan, after being diagnosed with the disease last Monday.
Tian Yong, office director of Shadi township in Enshi city, in the Enshi Tujia and Miao Autonomous Prefecture, said Mr Lai returned to his home in Shadi on March 19 for the funeral of his uncle, who had died of cancer.
Mr Lai returned to Wuhan, where he worked as a security guard, on March 24. Mr Tian said it was unclear if Mr Lai had eaten chicken or been in contact with poultry during his five-day stay.
He said an investigation was under way, but preliminary analysis suggested Mr Lai could have contracted the disease elsewhere.
'No one from his home has developed any symptoms, and neither have those from his uncle's home, where he stayed for two days,' Mr Lai said. 'There haven't been any unnatural deaths of poultry or wild birds in Shadi.'