The carcass of the bird in the region of Varna confirmed that it was infected by the H5N1 strain, avian influenza or bird flu, Bulgarian daily Dnevnik reported on April 1 2010, quoting the Agriculture Ministry.

The carcass was analysed in the National Veterinary Service (NVS), the report said.

The dead bird was a common buzzard, inhabiting most of Europe and parts of Asia, which is very common in Bulgaria.

The European Public Health Alliance (SANCO) had been informed of the case, with additional preemptive safety measures were being implemented in the region of Varna, Dnevnik said.

Citizens were advised to contact the website of the NVS at http://www.nvms.government.bg/ or contact the emergency hot-line number 02 915 98 20 and inform the authorities of any dead birds that may be potentially infected with H5N1.

In March, an outbreak of avian influenza was confirmed in Romania in a backyard poultry farm in the commune of Letea, in Tulcea county, at the Danube's delta near the border with Ukraine.

At the time, this was first case the avian influenza H5N1 in the EU in a year. The previous case, confirmed in March 2009, concerned a wild duck in Germany.

Bird flu, or H5N1, is a subtype of the influenza A virus which can cause illness in humans and many other animal species.

It is considered an avian disease, although there is some evidence of limited human-to-human transmission of the virus. According to different media reports, there is a slight risk factor for contracting the virus when handling infected poultry, but transmission of the virus from infected birds to humans is thought to be low