The isolation and characterisation of astroviruses from chickens

Abstract

The isolation, cultivation and characterization of three chicken astroviruses (CAstV) isolates are described. They are antigenically related to each other but unrelated to avian nephritis virus (ANV) and duck hepatitis virus type 2 (DVH2) in neutralization, immunofluorescence and gel diffusion tests. CAstV, ANV and DVH2 all grew well in the LMH cell line, which was used for assay and serological tests. Serological surveys in 1982 and 2001 showed that antibody to CAstV virus was widespread in broiler and broiler breeder flocks and present in some turkey flocks. Infection of 1-day-old specific pathogen free chicks with one isolate in the laboratory resulted in mild diarrhoea and some distention of the small intestine. The virus could be isolated in high titres from all parts of the small intestine but rarely from other organs. Electron microscopic examination of purified particles of this agent revealed the presence of clusters of small round viruses with a diameter ranging from 25 to 30 nm. The amino acid sequence derived from the relatively conserved non-structural polyprotein region of this virus shows 62% identity with the corresponding region of turkey astrovirus 2, 58% identity with turkey astrovirus 1, 55% identity with avian nephritis virus and 33% identity with sheep astroviruses. Taken together, the results indicate that the agent is a new chicken astrovirus belonging to the family Astroviridae.

Identification of chicken enterovirus-like viruses, duck hepatitis virus type 2 and duck hepatitis virus type 3 as astroviruses

“…On the basis of antigenic and genetic relatedness shared with a reference CAstV isolate, first described by Baxendale & Mebatsion (2004), the ELV-3 and ELV-4 isolates can be regarded as different isolates of CAstV. Based on ORF 1b sequence comparisons, this work has also shown that ELV-1 represents an isolate of ANV, that the astrovirus DHV-2 is distinct from other avastroviruses, and that DHV-3 can also be identified an avian astrovirus.…”

“…The P22 18.8.00 isolate of CAstV, hereafter named the reference CAstV isolate, was obtained from Dr I. Tarpey, Intervet, Milton Keynes, UK. This virus, which was originally isolated and propagated in chick embryo liver (CEL) cells (Baxendale & Mebatsion, 2004), was passed twice in CEL cells before use in this investigation.…”

“…Exceptions include avian encephalomyelitis virus, a tentative member of the genus Hepatovirus (family Picornaviridae) (Marvil et al, 1999); duck hepatitis virus type 1 (DHV-1), a novel picornavirus ; another novel duck picornavirus ; and avian nephritis virus (ANV), characterized as a member of the genus Avastrovirus of the family Astroviridae (Imada et al, 2000). More recently, the characterization of a different astrovirus of chickens, named chicken astrovirus (CAstV), was reported by Baxendale & Mebatsion (2004).…”

Development of an indirect enzyme-linked immunosorbent assay test for detecting antibodies to chicken astrovirus in chicken sera

“…These have involved the application of indirect IF tests (McNeilly et al, 1994;Todd et al, 2009b) and a virus neutralization (VN) test, which was based on the first characterized CAstV isolate (Baxendale & Mebatsion, 2004). The use of an ELISA for detecting CAstV antibodies in experimentally vaccinated chickens was also described by Sellers et al (2010).…”

“…CAstV was first characterized as a novel astrovirus by Baxendale and Mebatsion (2004), who reported the isolation of three antigenically similar viruses, exemplified by the P22-18.8.00 isolate, from outbreaks of runting stunting syndrome that occurred in the Netherlands in the 1980s. Since then CAstVs have been detected by reverse transcription-polymerase chain reaction (RT-PCR) in intestinal samples from growth-retarded and normal broilers reared in the USA, India, UK and other European countries Smyth et al, 2009Smyth et al, , 2010Bulbule et al, 2013).…”