An outbreak of Avibacterium paragallinarum serovar B in a Thai layer farm

Abstract

Avibacterium paragallinarum serovar B was diagnosed and revealed in a layer farm. The infected chickens showed mucous nasal discharge, facial edema and conjunctivitis. Egg production also decreased dramatically. Necropsy findings showed lesions of conjunctivitis and edematous tissue around the eyes. The infraorbital sinuses were filled with a caseopurulent mass and tracheitis. Bacterial isolation and identification was performed and confirmed by PCR technic. A hemagglutination inhibition test using specific antibodies against serovar B revealed the Avibacterium paragallinarum serovar B infection. A pathogenicity test done in 10 layer chickens, showed clinical signs of nasal discharge, facial edema and conjunctivitis. This is the first report of an outbreak of infectious coryza caused by A. paragallinarum serovars B in Thailand.