Flu’s coming, but which kind?
The beginning of autumn brings not just the start of another school year, but also the prospect of another flu season. Last spring, Chinese authorities announced the discovery of a strain of flu, H7N9, that passed from birds to humans, and that has limited transmission among humans. Even as that announcement conjured up memories of the 2009 swine flu pandemic, public health officials were keeping an eye on a second ailment, a respiratory virus that emerged in Saudi Arabia in 2012, which itself was reminding people of the 2002-2003 SARS epidemic. SARS, or severe acute respiratory syndrome, rapidly spread from Hong Kong to 37 countries. The new virus, discovered in Saudi Arabia in 2012, is called Middle East respiratory syndrome, or MERS. Both ailments can be dangerous. According to the U.S. Centers for Disease Control and Prevention, H7N9 has killed 45 of 135 people known to have contracted it, while MERS has...