ABSTRACT
In March 2013, the People’s Republic of China (hereafter referred to as China) reported to the World Health Organization (WHO) that it had detected three human cases of a novel bird flu strain. Two of them proved fatal (Lancet 2013). The spread of the strain appeared to be limited to instances of direct contact between poultry and humans. WHO announced the new strain, H7N9, to the world the following day, including on Twitter. That same day, WHO’s original tweet, which linked to a press announcement in Geneva, generated 100–200 retweets per hour. Over the next four days, retweets rose to 500 per hour (Norris 2013). It is clear that the Internet has become an important mechanism for reporting information about disease outbreaks. What is less clear is what sort of mechanism it is.
