Since the first cases of the deadly H7N9 bird flu strain appeared in Shanghai earlier this month, Chinese health officials told the world not to panic because they couldn't find solid evidence of human-to-human transmission in any of what have grown into 82 reported infections. They maintained that until, well, guess what China's health experts are saying for the first time today? "Human-to-human transmission, in theory, is possible, but is highly sporadic," Feng Zijian, director of the health emergency center of the Chinese Center for Disease Control and Prevention, told reporters in China on Thursday. "Further investigations are still under way to figure out whether the family cluster involved human-to-human transmission," Feng added.  

The "family cluster" he's talking about is a case in which two sons may have contracted bird flu from their father, an 87-year-old man thought to be the first reported case of China's H7N9 virus, according to China Daily. Perhaps even more worrisome: The World Health Organization said Wednesday that there are other humans, aside from the two brothers being investigated, who appear to have contracted the deadly virus without any contact with poultry. (Even though it's called bird flu, that's how the Contagion thing was supposed to work with the spread of H729.) "It might be because of dust at the wet markets, it could be another animal source beside poultry, it could also be human-to-human transmission," WHO spokesman Gregory Hartl told Reuters. So, to be clear, officials aren't quite sure how people who aren't handling poultry are getting this strain of bird flu. And, to be sure, that's pretty scary.

Based on their experience with other strains of bird flu, Chinese health officials maintain that if H729 is, indeed, in the human-to-human transmission phase, it's only on a very small scale. "Zeng Guang, chief epidemiologist with China CDC, said people infected with H7N9 can transmit the virus within a period of time, in which they could possibly infect others," reported China Daily. But, Feng added, "that's highly rare and could be limited to within a family" ... "people don't need to panic, because such limited human-to-human transmission won't prompt a pandemic." As of Thursday 17 of the 82 infected people have died.