AFP - The virulent form of H5N1 bird flu virus is spreading in Romania where the number of infected sites rose by 20 to 75, veterinary officials said.

In addition, 35 other possible sites were being investigated, the National Veterinary Health Authority said.

The capital Bucharest was among the areas affected with the virus, which reappeared at a poultry farm in Codlea two weeks ago, it said. The disease was first detected here late last year.

The Romanian veterinary authorities in a statement blamed the latest spread of the disease on migratory birds and the failure to take proper steps to isolate the virus at the Codlea farm.