Swollen head syndrome associated withE. coliand infectious bronchitis virus in the Central Valley of California

Abstract

SUMMARYA commercial broiler flock in the Central Valley of California experienced a sudden increase in mortality due to heavy culling. Clinical signs included a snick, swollen heads and severe depression. Necropsy and histology revealed tracheitis, rhinitis, facial cellulitis, blepharitis, episcleritis, otitis media and caseous exudate within the air spaces of cranial bones. Escherichia coli serotype O78 was isolated from all lesions. Infectious bronchitis virus (Massachusetts serotype) was isolated from trachea/nasal cavity tissue pool. Adenovirus group 1 was isolated from trachea/nasal cavity and caecal tonsil tissue pools. Serum samples were positive for infectious bronchitis using ELISA and haemagglutination inhibition tests, but negative for turkey rhinotracheitis by an ELISA using the British antigen. This case suggests that swollen head syndrome can be associated with viruses other than pneumovirus.

Detection of infectious bronchitis virus

“…This virus could subsequently be missed by the IBV detection system. This is especially important for field samples in which double infections are quite common (Gelb, 1989;Gelb et al, 1989;Droual & Woolcock, 1994;De Wit, unpublished data, 1995;Cavanagh et al, 1998Cavanagh et al, , 1999.…”

Attempts to reproduce swollen head syndrome in specific pathogen‐free chickens by inoculating withEscherichia coliand/or turkey rhinotracheitis virus

“…In Experiment 1, the chickens which were inoculated into the SN or SE with E. coli showed typical lesions of SHS; facial swelling due to facial cellulitis, blepharitis and periophthalmitis, and infraorbital sinusitis (Morley & Thomson, 1984;Pattison et al, 1989;Randall, 1991;Uramoto et al, 1990;Nunoya et al, 1991;Droual & Woolcock, 1994;Nakamura et al, 1997). Purulent inflammation of air spaces and middle ears in the inoculated chickens were recognized in field cases of SHS (Pattison et al, 1989;Randall, 1991;Droual & Woolcock, 1994;Nakamura et al, 1997).…”

“…Then, clinical SHS occurred in Europe (O'Brien, 1985;Pattison et al, 1989;Hafez & Lohrem, 1990) Asia (Uramoto et al, 1990;Lu et al, 1994) and America (Droual & Woolcock, 1994). Turkey rhinotracheitis (TRT) virus antibodies were only detected in chicken sera in the United Kingdom after the onset of SHS (Cook et al, 1988).…”

“…TRT virus, a pneumovirus, has been strongly implicated as a factor in SHS in chickens (Naylor & Jones, 1993). Escherichia coli has been consistently isolated from skin lesions of the head (Morley & Thomson, 1984;O'Brien, 1985;Pattison et al, 1989;Uramoto et al, 1990;Droual & Woolcock, 1994;Tanaka et al, 1995;Nakamura et al, 1997). Therefore, E. coli is thought to be a secondary complicating factor (Naylor & Jones, 1993).…”

“…Therefore, E. coli is thought to be a secondary complicating factor (Naylor & Jones, 1993). The first invasive sites of bacteria in the subcutaenous tissue of heads were estimated to be the eyelid or nasal membrane, because there was rhinitis (Morley & Thomson, 1984;Nakamura et al, 1997) and blepharitis (Nunoya et al, 1991;Droual & Woolcock, 1994;Nakamura et al, 1997).…”