Doctors on alert over new bird flu Australian health authorities are preparing to combat China's new strain of bird flu amid fears it is one of the most lethal influenza viruses the world has seen. While there is still no evidence people can spread H7N9 bird flu to others, the Australian government is warning travellers and doctors to be alert to symptoms while Melbourne scientists work on a vaccine to prevent it. The deputy director of the World Health Organisation's Collaborating Centre for Reference and Research on Influenza in Melbourne, Dr Ian Barr, said his team had acquired samples of the new virus to develop a vaccine with CSL. While the team is one of several working on a vaccine worldwide, Dr Barr said they should have a solid candidate within two or three weeks. We need to be vigilant. This virus obviously has the ability to infect humans at some level," he said. It doesn't appear that it is easily transmissable between people, which is good, but we have to be ready because these viruses can change. On Thursday, flu expert Dr Keiji Fukuda, leading a team of researchers for the WHO in China, said although they were still trying to understand the virus, it appeared to be "unusually dangerous." This is definitely one of the most lethal influenza viruses we have seen so far. We think this virus is more transmissible to humans than H5N1," he said, referring to the strain the WHO estimates has killed more than 360 people since 2003. The likely source of infection was poultry, as chickens, ducks and pigeons from poultry markets had tested positive for H7N9. China has confirmed 108 cases and 22 deaths since the infections were announced on March 31, with a higher proportion of cases in older people. The first case to be diagnosed outside of China was in Taiwan on Wednesday. It was reported a 53-year-old man, who had been working in Jiangsu province in China before he fell ill, claimed he had not been exposed to birds or poultry, nor had he consumed any undercooked poultry or eggs. Experts are worried about the prospect of such a virus mutating into a form easily transmissible between humans because it could trigger a pandemic. Chinese health officials have acknowledged so-called "family clusters," where members of a single family have become infected but have so far declined to put it down to human-to-human transmission. So far, most H7N9 cases have been confined to Shanghai and nearby provinces in eastern China. A spokeswoman for Australia's department of health said doctors and laboratories had been given information about the virus and infection control guidelines in case it emerges. Australian travellers have also been told to avoid animals and practice good hand hygiene. The spokeswoman said the national medical stockpile had antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza), which are effective against the new bird flu strain if taken early in the course of the illness. Earlier this month, Australia's Chief Medical Officer, Professor Chris Baggoley, convened a meeting of the Australian Health Protection Principal Committee - the peak health emergency management body which comprises all state and territory Chief Health Officers - to review the country's preparedness for a potential national response. It is now offering daily updates on the virus.