Feb. 10 (Bloomberg) — Nigeria blamed smugglers for bird-flu infections that have spread to at least four farms, as authorities in Greece and Bulgaria probe possible outbreaks of the lethal H5N1 virus strain, the first in the European Union.

The “activities of illegal importers and smugglers of pets and birds” brought the virus to Nigeria, Agriculture Minister Adamu Bello said yesterday as the virus was found on three more farms. The World Organization for Animal Health said migratory birds most likely introduced the disease, which killed 40,000 fowl in an initial outbreak in Nigeria that began a month ago.