Bulgaria on Wednesday closed poultry markets in the northeast of the country after bird flu was detected in a village over the border in southeast Romania, the Agriculture Ministry said.
Bulgaria also banned keeping poultry outdoors and ordered measures to prevent wild birds from coming into contact with winter feed stocks, the ministry said in a statement.
Police were also instructed to monitor poultry transports and the veterinary services to intensify checks on poultry farms and on wild birds, the statement continued.
Earlier Wednesday, the Romanian national veterinary service ANSVSA said bird flu had been detected in a village on the Danube delta in south-east Romania.
Romania has been among the European countries worst hit by bird flu, with some 55 outbreaks of the disease in 2005 and another 150 in May 2006 in breeding farms in the centre of the country.
Health authorities responded by slaughtering over one million birds to prevent the disease from spreading further.
The virus is regarded as a global threat because scientists fear it could mutate into a form that is easily spread among humans, leading to a pandemic with the potential to kill millions.
Worldwide the H5N1 virus has killed 192 people out of 319 infected patients since reappearing in late 2003, according to a World Health Organisation toll published in July.