Author's Organization：
From the Mukden Institute for Infectious Diseases of Animals, Mukden, Manchoukuo.
From the Mukden Institute for Infectious Diseases of Animals, Mukden, Manchoukuo.
From the Mukden Institute for Infectious Diseases of Animals, Mukden, Manchoukuo.
From the Mukden Institute for Infectious Diseases of Animals, Mukden, Manchoukuo.
From the Mukden Institute for Infectious Diseases of Animals, Mukden, Manchoukuo.