''Hepacivirus A'', or Canine hepacivirus (CHV) or Equine hepacivirus (EHV), is a

positive-sense single-stranded RNA virus Positive-strand RNA viruses (+ssRNA viruses) are a group of related viruses that have positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated into ...

of the genus ''

Hepacivirus ''Hepacivirus'' is a genus of positive-strand RNA viruses in the family ''Flaviviridae''. The hepatitis C virus (HCV), in species ''Hepacivirus C'', infects humans and is associated with hepatitis and hepatocellular carcinoma. There are fourteen ...

''. It infects dogs and horses, and causes pulmonary infections in dogs. Unlike the related

Hepatitis C virus The hepatitis C virus (HCV) is a small (55–65 nm in size), enveloped, positive-sense single-stranded RNA virus of the family ''Flaviviridae''. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer ( hepato ...

, it is not known to cause

hepatitis Hepatitis is inflammation of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pa ...

in either host.

History

The virus was isolated in 2011 from a number of dogs suffering from respiratory infections. Later, distinct lineages were isolated from horses in different locations.

Genome

As of 2012, the genome has not yet been fully sequenced. The available sequence is about 6,500

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...

s in length. It is predicted to have a

polyprotein Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called protease ...

that can be cleaved into 10 smaller proteins. There is a '

slippery sequence A slippery sequence is a small section of codon nucleotide sequences (usually UUUAAAC) that controls the rate and chance of ribosomal frameshifting. A slippery sequence causes a faster ribosomal transfer which in turn can cause the reading ribosome ...

' – A₅NNA₅ – within the genome which may encode a programmed

frameshift Ribosomal frameshifting, also known as translational frameshifting or translational recoding, is a biological phenomenon that occurs during translation that results in the production of multiple, unique proteins from a single mRNA. The process can ...

. It encodes two

envelope protein A viral envelope is the outermost layer of many types of viruses. It protects the genetic material in their life cycle when traveling between host cells. Not all viruses have envelopes. Numerous human pathogenic viruses in circulation are encase ...

s (E1 and E2) as well as

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometime ...

and

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − form un ...

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

s. The overall G+C content is 50.7%.

Evolution

The virus appears to have evolved from the

between 500 and 1,000 years ago. The equine lineages (EHV) are more diverse than the canine lineages (CHV), suggesting that the former are ancestral to the latter. CHV appears to have originated in a

cross-species transmission Cross-species transmission (CST), also called interspecies transmission, host jump, or spillover, is the transmission of an infectious pathogen, such as a virus, between hosts belonging to different species. Once introduced into an individual of a ...

from horses to dogs around 1970. The origin of EHV is not known, but it seems that both EHV and Hepatitis C virus have originated in separate cross-species transmission events from a common source.

References

{{Taxonbar, from=Q29006891, from2=Q5032408 Dog diseases Hepaciviruses Animal viral diseases