It was a once-commonplace childhood disease which was thought to have been virtually conquered, but a massive increase has been reported in the number of youngsters in the south catching whooping cough.
In extreme cases the disease can be fatal.
512 cases have already been reported in the Meridian region since the start of this year - that's more than five times the number diagnosed four years ago.
The south east has seen the biggest rise in the country.
- Hampshire and Isle of Wight had 14 cases in 2008 and 126 cases between January and June this year.
- Kent had 14 cases in 2008 and 50 cases between January and June this year
- Sussex and Surrey had 17 cases in 2008 and 231 cases between January and June this year.
- Thames Valley had 46 cases in 2008 and 105 cases between January and June this year.