H7N9 is a new highly dangerous strain of influenza which originated in birds, and now has infected 82 people and killed 17 in China. What makes this virus so dangerous is because the symptoms are not apparent until several days after it is “caught”, and because the manner in which it spreads is still undetermined.
Fortunately, the way that epidemics are handled in the world today has vastly improved since the outbreak of SARS (also originating in China) ten years ago, which killed nearly 800 people. A big reason that SARS infected so many people and caused such an international terror was because the Chinese government initially tried to cover up it’s existence, fearing the bans on travel and other sanctions from the World Health Organization and other international health authorities. As technology has improved, so has the understanding of how these epidemics spread, which has lead to a decrease in the severity of the sanctions for infected nations. The sanctions which remain are hardly detrimental to the host country, but still (hopefully) effectively quarantine infected persons to isolate the spread of the virus/disease.
The really interesting threat presented by H7N9 is its implications. If a person can merely become infected with H7N9 (or any other variant, future strain) by being in the general vicinity of, or having minimal physical contact with, an infected person, the world could be in a dire situation. Due to globalization and cheap travel prices the amount of people who could become infected would balloon, possibly exponentially. Our world population is enormous, and if history is any indication, mother nature has forms of checks and balances to keep population at a reasonable level. If a new disease or virus was to originate in a country a little less experienced than China in handling epidemics, a real crisis could occur.