The latest outbreak of the flu virus – known as the H5 avian influenza virus – was announced on Wednesday (June 13) at a bird farm in the village of Donchevo.
Donchevo is situated on the west coast of Bulgaria, approximately 500 kilometres from the Bulgarian capital, Sofia.
The National Food Safety Agency has setup a three-kilometre protection zone around the farm.
The sale of eggs and the movement of domestic, wild and other birds was banned within it.
In a statement, the agency said: “All contaminated and contact birds in two of the farm halls will be culled in a humane manner.”
Two weeks earlier, the agency authorities reported an outbreak of the virus on a duck farm in the village of Stefanovo and said birds on the farm were being culled.
The Stefanovo outbreak – which broke out approximately 306 kilometres from latest outbreak site – was the second of its kind at the facility since October last year, when more than 10,000 ducks were culled.
And in April of this year, an outbreak was recorded in Zimnitsa, Straldzha municipality, Yambol district, which resulted in 6,000 ducks being destroyed.
Bulgaria has reported a handful of outbreaks in the past year, some involving the highly pathogenic H5N8 bird flu virus.
In March, a South Korean farm Eumseong, North Chungcheong Province – around 131km from Seoul – was found to have the H5 virus.
Quarantine officials slaughtered around 20,000 quails being raised at a farm 3km (1.8m) away from the site, as a preventative measure.
South Korean news agency Yonhap reported: “The provincial Government imposed a standstill order for 24 hours in areas within 10 kilometres (6.2m) of the site to help contain further spread of the disease.”
The virus was discovered during an inspection before the farm began to sell ducks.
And in March of this year, the NHS warned of a deadly strain of bird flu.
The H5N1 virus has infected 860 people worldwide, according to latest World Health Organization figures. More than 450 people have died.
Since March 2013, the H7N9 virus has infected 1,565 people, and 612 people have died from the flu virus. The NHS advised the public on how to reduce the risk of infection.
Meanwhile, the deadly Aussie flu virus is still spreading across the UK.