An occurrence of avian tuberculosis in hooded merganser (Lophodytes cucullatus).

Two imported male hooded mergansers (Lophodytes cucullatus) were introduced into a zoological aviary in Japan, and one of them died 10 mo later. Postmortem revealed numerous white yellowish nodules of various sizes in the liver. Two large nodules were also observed below the right lung and on the top of the left kidney. Histopathologically, a large number of tubercles with acid-fast bacilli were seen in the liver. The amyloid was deposited in the connective tissue of the tubercles. Bacteriologically, Mycobacterium avium serovar 1 was isolated from the liver.