According to state media reports, the number of human cases of H7N9 increased to sixty, while two more deaths in Shanghai have increased the death toll to thirteen. For the first time, officials say the virus has spread beyond the eastern region of China. The H7N9 strain is common in birds; however, it was never known to infect people until last month. The World Health Organization says China has been infected with a new variation of the bird flu. As of now, the organization cannot determine the source of the infection, but investigations show no evidence of ongoing human to human transmission. Officials have listed poultry markets as a possible source of the infection. Several poultry markets have either closed or suspended trading in live poultry in effort to help with the problem, as they are the main focus of the investigation. Experts from the New England Journal of Medicine say the new strain of bird flu contains genetic characteristics that make it adaptable to infect humans. Chinese researchers say the H7N9 virus could have come from birds that have migrated from East Asia.