It has yet to be determined how a father and son from Nanjing in Jiangsu province became China's latest bird flu victims, although the World Health Organization (WHO) said it believes human-to-human transmission is unlikely. The son died on December 2, becoming China's 17th bird flu fatality, while the father, who fell ill on December 3, is recovering, the South China Morning Post reported. Despite fears that the H5N1 strain of the virus could have spread from son to father, Hans Troedsson, the WHO's China representative, played down speculation, saying that the results of gene sequencing on a sample taken from the son showed no mix of human genes and no significant mutation. Troedsson added that the father was recovering because he was treated with Tamiflu once his symptoms became apparent. The Ministry of Health said the neither father nor son had any known contact with live or dead poultry.