Genus: Avihepatovirus


Genus: Avihepatovirus

Virion

Morphology

No surface morphology is visible by EM.

Physicochemical and physical properties

Avihepatoviruses are both heat and acid stable.

Nucleic acid

Length of genome (Kim et al., 2006): up to 7,792 nt (5'-UTR: 625-655 nt, ORF: 6,750-6,756 nt, 3'-UTR: c. 318 nt). 5'-UTR contains a type IV IRES. The location of the cre has not been identified.

Genome organization and replication

Genome layout: VPg+5'UTRIRES-IV[1AB-1C-1D-2A1npgp/2A2NTPase-2A3H-box/NC-2B-2C/3A-3B-3C-3D]3'UTR-poly(A)

The deduced polyproteins of the three types have lengths of 2,249-2,251 amino acids. There is no L protein. The 1AB polypeptide remains uncleaved and lacks a myristoylation signal. The genome sequences of all three DHAV types have three 2A motifs: i) NPGP; ii) AIG1-type guanine nucleotide-binding domain (GxxGxGKS NTP-binding motif); and iii) a H-box/NC motif. However, it is not clear if this genome region encodes one, two or three mature polypeptides. 3Dpol exhibits a CSG rather than PSG sequence motif.

Antigenicity

Avihepatoviruses are divided into three genetic types, duck hepatitis A virus (DHAV) 1 to DHAV-3. DHAV-2 and DHAV-3 are not neutralized by DHAV-1 antiserum; however, the relationship between types 2 and 3 remains unstudied.

Biology

DHAV causes a highly fatal contagious disease of young ducklings, 1-28 days of age. The onset of the disease is very rapid, it spreads quickly through the flock and may cause up to 90% mortality. Sick ducklings develop spasmodic contractions of their legs and die within an hour in a typical "arched-backward" position. The liver is enlarged and shows hemorrhagic spots. A DHAV-1 live-attenuated vaccine is widely used.

Member Species

SpeciesVirus name(s)Exemplar isolateExemplar accession numberExemplar RefSeq numberAvailable sequenceOther isolatesOther isolate accession numbersVirus abbreviationIsolate abbreviation
Avihepatovirus Aduck hepatitis A virusR85952DQ226541NC_008250Complete genomeDHAV

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.
Download GenBank/EMBL query for sequences listed in the table here.

Derivation of names

Avihepato: from avian and Greek hepatos, "liver"