HOUSTON --Houston has been named one of America's sickest cities. The online news site The Daily Beast compiled a list of the nation's 20 sickest cities when it comes to the flu. Editors used positive flu test rates, vaccination numbers and the length of the flu season to determine just how prevalent the bug is in each city. Dayton, Ohio took the number one spot. Houston came in 18th. But we're not the only Texas city to make the list -- San Antonio came in 8th and Dallas took the number 14 spot.