The number of flu cases in six Bulgarian regions is on the rise. Plovdiv, Haskovo, Yambol, Smolyan, Pazardjik and Vidin are experiencing an epidemic. The infection rate is under control in Pleven and Shoumen.

Schools in several cities closed down to stop the spread of infections. The sharp temperature changes aid the easy spread of the virus, Dnevnik newspaper reported.

Though many regions are affected, the number of sick people has decreased by more than 1000. Last week 13 900 people suffered from flu. This week the number of cases does not exceed 12 400, Health Ministry data shows.

Bulgaria is experiencing the annual flu epidemic later than usual this year. It started in the middle of February and medics predict it will finish in the end of March.

Doctors advise people to avoid large social gatherings in order to protect themselves. One virus type has been identified but lab experts said at least two more flu viruses affect people at present.