Infectious bovine rhinotracheitis virus

Synonym for Bovine herpesvirus 1.

Infectious bronchitis virus (IBV) The type species of the genus Coronavirus. The cause of a common, contagious, acute respiratory disease of chicks. Neutralization tests using chick embryos indicate multiple variant antigenic types. All strains show some antigenic relationships but are unrelated to other coronaviruses. Beaudette strain (IBV-42) is serologically similar to Massachusetts strain, although on egg passage it has become lethal for chick embryos but has lost infectivity for older birds. Chicks up to 4 weeks old are most susceptible. They show depression and gasping; rales are heard. The disease lasts 6-18 days and the mortality is up to 90%. In laying birds there is a drop in egg production and eggs are defective. Pheasants may be infected. Mild endemic infection may result in poor egg production and predispose to bacterial respiratory disease. Avian nephrosis and visceral gout may be caused by the virus, possibly by certain strains (see Australian infectious bronchitis virus). The virus is very infectious and spreads by the respiratory route. Birds are infectious for up to 35 days after recovery but there is no evidence of a carrier state. Virus can be isolated from eggs and semen of experimentally infected birds. An attenuated vaccine has been used. Antibodies have been found in humans who handle poultry. Replicates on the CAM but produces no definite pocks. In chick embryo cell cultures there is replication with syn-cytium formation and cell necrosis. The viral RNA is a single piece of single-stranded RNA of mol. wt. 9x10« (27.6kb). Replication involves synthesis of a nested set of 3' co-terminal subgenomic mRNAs that are 5' capped and 3' polyadenylated. Only the 5' unique regions of these mRNAs are translated. There are at least five viral polypeptides: spike, membrane, nucleocapsid, hemagglutinin-esterase and small membrane protein. Synonyms: gasping disease virus; avian infectious bronchitis virus.

Gough RE et al (1992) Vet Rec 130, 493 King DJ and Cavanagh D (1991) In Diseases of Poultry, Ninth edition, edited by BW Calnek et al. Ames: Iowa State University Press, p. 471

infectious bulbar paralysis virus Synonym for pseudorabies virus.

Infectious bursal disease virus (IBDV) The type species of the genus Avibirnavirus. The virion has a single capsid structure of 32 capsomeres. The genome consists of two segments of double-stranded RNA 3128 and 2795bp in length, with a 5' genome-linked protein (VPg) on each segment and no 3' poly A. There is no envelope. Diameter is 60nm, density about 1.32g/ml. Capsid composed of four major polypeptides. Replicates in chicken embryo fibroblasts rather than in epithe-lioid cells. Resistant to ether, chloroform, pH2 and incubation at 56°C for 5 h; difficult to remove from chicken houses. Causes an acute, highly contagious lymphoproliferative condition of chickens; 2- to 15-week-old birds are most commonly affected. The bursa of Fabricius is involved, so that the immune system does not develop properly, resulting in an inability to resist other infections. There is nephrosis. Transmission is probably via food and water. Egg- or mouse-adapted attenuated virus has been used as a vaccine with success. Two serotypes of IBDV have been identified by cross-neutralization. Serotype 1 strains are pathogenic in chickens whereas serotype 2 strains are non-pathogenic. The three-dimensional structure of the virus has been determined. Synonyms: avian nephrosis virus; Gumboro disease virus; infectious bursitis virus (see Table I1).

Bottcher B et al (1997) J Virol 71, 325 Dobos P et al (1979) J Virol 32, 593 Kilbenge FSB et al (1988) J Gen Virol 69,1757 Mahardika GNK and Becht H (1995) Arch Virol 140, 765

Morgan MM et al (1988) Virology 163, 240

infectious canine hepatitis virus Synonym for canine adenovirus 1.

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