The father of a Chinese man who died of bird flu has also been infected with the H5N1 virus that causes the disease, the World Health Organization reported Friday, saying it could not rule out the possibility of human-to-human infection, according to AP. Joanna Brent, a Beijing-based WHO spokeswoman, said the father began presenting symptoms on Monday and was confirmed as having the virus on Wednesday. She said he was being monitored in hospital. «Because the possibility of human to human transmission cannot be ruled out, we will be monitoring this case closely,» Brent told The Associated Press. «If it is found to be easily passed between humans, we would be concerned,» Brent said. Brent said there was no evidence that the man had been infected by his 24-year-old son, who died on Dec. 2, but said the possibility could not yet be eliminated. Chinese news reports gave the man's age as 52. Both he and his son, who lived in the eastern province of Jiangsu, were identified only by their surname, Lu. Brent said it was also possible that both men were infected by the same bird, or that they were infected separately from different sources. Brent said health authorities were monitoring another 68 people who were in close contact with the son, none of whom have so far shown symptoms of H5N1 infection. She said that seemed to indicate that it was unlikely that the virus was being easily passed between humans.