8-17-12 (St. Paul, MN)  --  As the school season in Minnesota approaches, this year's outbreak of whooping cough is becoming a big concern.  There have been nearly 2,400 cases of whooping cough - or Pertussis - in the state so far this year. That's the most reported since 1947, some 65 years ago.  About half of the cases of whooping cough in Minnesota have been in the seven-county metro area.  Nationally, the number of cases reported to the CDC is quickly approaching 20 thousand, with 10 related deaths.