A woman farmer in China's southeastern province of Fujian has been infected with the H5N1 form of bird flu, state media said on Thursday, the first human case in the country in about seven weeks, according to Reuters. The 44-year-old woman from Jianou city was being treated in hospital, according to the official Xinhua news agency. "Tests by the Chinese Centre for Disease Control and Prevention on the patient have confirmed that the patient has been infected with the bird flu virus strain H5N1," it said. In Geneva, the World Health Organisation (WHO) said that the woman had become ill on Feb 18 and she remained in hospital in critical condition. "Information provided to WHO indicates that she is a farmer who kept birds in her backyard and was possibly exposed to sick birds," it said in a statement. An investigation was under way to determine if this exposure was the source of her infection. The Ministry of Health confirmed the news,but gave no other details. The WHO said the woman had tested positively for the H5N1 virus in a provincial laboratory, whose results had been confirmed by a national laboratory on Tuesday. The Ministry of Agriculture said an investigation team it sent down to the woman's village found no trace of the virus in poultry samples. "The initial analysis is that we cannot rule out the possibility of infection through contact with a virus-carrying wild bird," it said in a statement. The ministry added it was stepping up poultry vaccinations, and had sealed off the woman's house and surrounding area while it was disinfected. Hong Kong's government also said it had been notified by mainland authorities of the new case. The Department of Health in Hong Kong said in a statement it was maintaining close contacts with its Chinese counterpart and hoped to obtain more information. China's last confirmed human case was reported in January. The farmer, from eastern Anhui province, recovered. China has now reported a total of 23 human cases of bird flu, including 14 deaths, since 2003 and, with the largest poultry population and millions of backyard birds roaming free, it is seen as central to the fight against the virus. Bird flu