Isolation of a TRTV-like virus from chickens with swollen-head syndrome

The available detection methods for avian pneumoviruses (turkey rhinotracheitis virus; genus Metapneumovirus) in turkeys, domestic fowl and other species are reviewed. The advantages and disadvantages of virus isolation techniques, virus or genome (polymerase chain reaction) detection and serology are discussed. Some of the problems likely to be encountered are considered, including the detection of yet to be discovered subtypes, as are the factors that are likely to influence the outcome of the work.

Section: Alternative Approachesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection and differentiation of avian pneumoviruses (metapneumoviruses)

Cook¹,

Cavanagh

2002

“…Since then, there have been many reports associating SHS with a pneumovirus serologically indistinguishable from turkey rhinotracheitis virus (TRTV) (O'Brien 1985;Picault et al, 1987;Wyeth et al, 1987;Buys et al, 1989;Jones et al, 1991). A firm association between SHS and pneumovirus infection in chickens has become established in the literature (Alexander, 1991(Alexander, , 1993.…”

Section: Introductionmentioning

confidence: 99%

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

Droual¹,

Woolcock²

1994

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.

“…In some instances, APEC has been associated with peculiar diseases in specific avian species. In chickens, swollen head syndrome often results from synergistic infection of turkey rhinotracheitis virus and E. coli (Morley & Thompson, 1984;Picault et al, 1987;Stehling et al, 2003). Turkey rhinotracheitis virus is believed to cause initial acute rhinitis that is followed by invasion of the facial subcutaneous tissues by E. coli (Picault et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…In chickens, swollen head syndrome often results from synergistic infection of turkey rhinotracheitis virus and E. coli (Morley & Thompson, 1984;Picault et al, 1987;Stehling et al, 2003). Turkey rhinotracheitis virus is believed to cause initial acute rhinitis that is followed by invasion of the facial subcutaneous tissues by E. coli (Picault et al, 1987). In turkeys, APEC also causes osteomyelitis complex characterized by lesions including green discolouration of the liver, arthritis/synovitis, softtissue abscesses, and osteomyelitis of the proximal tibia in an otherwise normal-appearing processed turkey carcass (Huff et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Colibacillosis in poultry: unravelling the molecular basis of virulence of avian pathogenicEscherichia coliin their natural hosts

Dziva¹,

Stevens²

2008

303

222

Avian colibacillosis is caused by a group of pathogens designated avian pathogenic Escherichia coli (APEC). Despite being known for over a century, avian colibacillosis remains one of the major endemic diseases afflicting the poultry industry worldwide. Autologous bacterins provide limited serotype-specific protection, yet multiple serogroups are associated with disease, especially O1, O2 and O78 among many others. Experimental infection models have facilitated the identification of some key APEC virulence genes and have allowed testing of vaccine candidates. Well-recognized virulence factors include Type 1 (F1) and P (Pap/ Prs) fimbriae for colonization, IbeA for invasion, iron acquisition systems, TraT and Iss for serum survival, K and O antigens for anti-phagocytic activity, and a temperature-sensitive haemagglutinin of imprecise function. Intriguingly, these factors do not occur universally among APEC, suggesting the presence of multiple alternative mechanisms mediating pathogenicity. The recent availability of the first complete APEC genome sequence can be expected to accelerate the identification of bacterial genes expressed during infection and required for virulence. High-throughput molecular approaches like signature-tagged transposon mutagenesis have already proved invaluable in revealing portfolios of genes expressed by pathogenic bacteria during infection, and this has enabled identification of APEC O2 factors required for septicaemia in the chicken model. Complimentary approaches, such as in vivo-induced antigen technology, exist to define the activities of APEC in vivo. In recent years, reverse vaccinology and immuno-proteomic approaches have also enabled identification of novel vaccine candidates in other bacterial pathogens. Collectively, such information provides the basis for the development or improvement of strategies to control APEC infections in the food-producing avian species.