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

Abstract

Earlier work identified and biologically characterized antigenically distinct enterovirus-like viruses (ELVs) of chickens. Three of these ELVs can now be identified as astroviruses. Characterization involved the use of a hitherto undescribed, degenerate primer-based reverse transcription-polymerase chain reaction (RT-PCR) to amplify astrovirus open reading frame (ORF) 1b-specific cDNA fragments followed by nucleotide sequence determination and analysis of the amplified fragments. ELV-1 was confirmed as an isolate of the astrovirus avian nephritis virus (ANV). ELV-4 (isolate 612) and ELV-3 (isolates FP3 and 11672) were antigenically and genetically related to the second characterized astrovirus of chickens, namely chicken astrovirus (CAstV). Using indirect immunofluorescence, the FP3 and 11672 ELV-3 isolates were very closely related to one another, and less closely related to ELV-4 and the previously described CAstV (P22 18.8.00 reference isolate). Comparative analyses based on the ORF 1b amplicon sequences showed that the FP3 and 11672 ELV-3 isolates shared high nucleotide (95%) and amino acid (98%) identities with one another, and lower nucleotide (76% to 79%) and amino acid (84% to 85%) identity levels with ELV-4 and the reference CAstV P22 18.8.00 isolates. The combined degenerate primer RT-PCR and sequencing methods also provided a nucleotide sequence specific to duck hepatitis virus type 2 (DHV-2) (renamed duck astrovirus) and duck hepatitis virus type 3 (DHV-3), which, for the first time, can also be identified as an astrovirus. Phylogenetic analyses based on the amplified ORF 1b sequences showed that ANV was the most distantly related avian astrovirus, with DHV-3 being more closely related to turkey astrovirus type 2 than DHV-2.

Detection and characterization of a new astrovirus in chicken and turkeys with enteric and locomotion disorders

“…An experimental infection of 1-day-old chicks with CAstV resulted in mild diarrhoea and distension of the small intestine. Recently, Todd et al (2009a) described the identification of an antigenically and genetically different CAstV that had been reported earlier as enterovirus-like virus (ELV) isolates FP3 and 11672 (Spackman et al, 1984). These viruses were originally isolated in the UK from flocks exhibiting early broiler mortality or hatchability problems.…”

Detection and characterization of avian nephritis virus in ducklings

“…DAstV genome possesses typical astrovirus organization and it was completely sequenced by Fu et al (2009). Duck hepatitis virus type 3 (DHV-3) was previously known as a picornavirus, but is newly identified as an astrovirus (Wang et al, 2008;Todd et al, 2009).…”

Isolation and Molecular Identification of Duck Hepatitis A Virus in Sharkia Governorate

“…There are three heterologus duck hepatitis virus (DHV) types; I, II and III [1]. The DHV type I has spread worldwide with mortalities more than 80% in ducklings less than 3 weeks of age [2]. Currently, DHV type I is renamed duck hepatitis A virus (DHAV) and subdivided into three genotypes DHAV-1, DHAV-2 and DHAV-3 [3].…”