TOKYO, April 29 (Xinhua) -- A Japanese national institute of animal health confirmed Tuesday that the H5 strain of the bird flu virus detected in several dead and dying swans in northeastern Akita Prefecture last week belongs to the highly virulent H5N1 strain.

    Upon receiving the result, the prefecture decided to carry out inspections in the following two days on about 42,000 birds at 15 farms within a radius of 30 kilometers around the location where the deadly virus was first detected, local government officials said.

    The prefectural government also called on farmers to check their animals and birds for abnormal symptoms.

    No widespread deaths of birds or animals have been reported in the region.

    The prefecture said Monday it detected the H5 strain of the bird flu virus in several dead and dying last week. Three dead swans and one dying swan were found on Monday last week near Lake Towada, with the virus being detected in three of them. Another dead swan and two dying swans were later found on the shores of the lake from Wednesday to Saturday.