Romania has introduced sweeping new measures after an outbreak of bird flu was confirmed in the Danube delta.
The cull of about 30,000 domestic birds has begun
They include culling poultry in the infected area, a buffer zone around it and a ban on hunting and fairs. The population is being inoculated.
"The only thing to contain the disease is to act very strongly... in the outbreak," said a government spokesman.
Tests confirmed that the Romanian virus was the same lethal strain which struck in Asia, killing more than 60 people.
The H5N1 strain has also caused heavy losses of livestock in south-east Asia since 2003.
Although its human victims contracted the disease from contact with birds, there are fears a mutant form of the virus may start passing between humans.
The World Health Organization has warned that millions could die in a global pandemic if this happens.
Cases of bird flu were reported in two villages in eastern Romania earlier this month.
According to the mayor of the first village affected, Ceamurlia de Jos, all 17,000 domestic birds in his village have now been killed.
The culling of more than 30,000 more in eight neighbouring villages has begun.
"We are killing all domestic birds there, burying them. We inoculate all the population in those villages. We have imposed strict measures for consumption of bird meat," agriculture ministry spokesman Adrian Tibu told the BBC.
H5N1 BIRD FLU VIRUS
Principally an avian disease, first seen in humans in Hong Kong, 1997
Almost all human cases thought to be contracted from birds
Isolated cases of human-to-human transmission in Hong Kong and Vietnam, but none confirmed
"You can't contain this thing well enough if you're talking about migratory birds," Mr Tibu told BBC Radio 4's PM programme.
The measures are already having a devastating impact on a region where poultry are the centre of the local economy, says the BBC's Nick Thorpe in eastern Romania.
People appear dazed by what is happening, but since it was confirmed that this is the strain of the bird flu virus found in Asia, they have begun co-operating closely with officials sent to collect their birds, our correspondent says.
Turkey has already reported the discovery of the lethal strain of the virus among birds in the west of the country.
The EU has banned imports of live birds and poultry products from Romania and Turkey.
EU veterinary experts said on Friday that the bird flu outbreak did not represent a risk to the general public "at present".
The H5N1 strain remained largely in South-East Asia until this summer, when Russia and Kazakhstan both reported outbreaks
Scientists fear it may be carried by migrating birds to Europe and Africa but say it is hard to prove a direct link with bird migration