SOFIA, Jan 12 (Reuters) - Bulgarian veterinary authorities on Wednesday said they will cull more than 5,800 ducks after detecting a bird flu outbreak at an industrial farm in the southern village of Zalti Bryag.

This is the fifth industrial farm hit by the highly pathogenic avian influenza type A in southern Bulgaria since December.

Bird flu is often fatal for poultry. It cannot be transmitted through food, though some human cases have raised concern among epidemiologists.

A wave of bird flu in Asia and Europe has a greater risk of spreading to humans because of a high number of variants, the World Organisation for Animal Health (OIE) said recently. (Reporting by Tsvetelia Tsolova Editing by David Goodman )