An avian influenza virus has already been found in six swans at the "Grudnjak" fish farm, which is only three to five kilometres away from Nasice as crow flies.
Later in the day the manager of the Nasice fish farm, Zdenko Ibriks, told reporters that 12 dead swans had been discovered at the farm, adding that five dead swans were discovered on Saturday and seven on Sunday.
The spokesman for the Ministry of the Agriculture, Forestry and Water Management, Mladen Pavic, confirmed the news, saying that samples had been taken from the seven dead swans discovered on Sunday.
Speaking at a news conference at the Agriculture Ministry, Brstilo said that the crisis management committee would decide today on launching preparations for the killing of poultry in the Nasice area, as had already been done in the area around the "Grudnjak" fish farm.
Brstilo said he was glad that there had been no reports of infection in domestic poultry.
This week the government will adopt a decision to pay compensation to people whose poultry was killed, and the damage is estimated at one million kuna (approx. 135,000 euros), Ministry spokesman Pavic said.
A total of 13,005 head of poultry were killed in nine communities in the "Grudnjak" fish farm area on 22 and 23 October. Poultry was killed in 370 out of 485 households owning poultry.
Brstilo reiterated that there was no danger for humans and no reason for panic, as the disease affected only birds. Croatia is the first country to have found the virus at the moment it entered the country with wild birds and it has taken all the necessary measures to prevent the spreading of the virus to domestic poultry, especially chicken farms, Brstilo said.
The consumption of poultry meat and poultry meat products is safe because poultry meat produced in Croatia comes from controlled poultry farms with high bio-safety standards, he said.
The head of the Poultry Centre at the Zagreb Institute of Veterinary Medicine, Vladimir Savic, said that the detected avian influenza virus was of H5 type, but that its N subtype was still unknown and that this would be established soon by Croatian laboratories and the EU avian influenza reference laboratory in Weybridge, UK.
The Poultry Centre has so far received 691 bird and domestic poultry samples for analysis, Savic said, adding that monitoring activities now covered domestic poultry from the general area where the infected swans were discovered. The centre has received 441 swab samples from wild fowl and domestic poultry and 250 different birds collected by members of the public or the veterinary service following citizens' reports.
There is a possibility that on their way to Croatia the infected swans also flew somewhere else, but so far there have been no reports of swan diseases from other countries, Savic said. He added that the swans were not ringed because they were young and that this was why it was impossible to establish where they had come from.
Brstilo said that the EU's chief commissioner for animal health on Sunday said he believed that Croatia had carried out all the necessary measures in the best possible way.