Hepatitis A causes

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]

Taxonomy

Viruses; ssRNA] viruses; ssRNA virus; positive-strand viruses; Picornavirales; Picornaviridae; Hepatovirus

Biology

Electron micrograph of the Hepatitis A virus (HAV), an RNA virus that can survive up to a month at room temperature. Courtesy: Public Health Image Library (PHIL), Centers for Disease Control and Prevention (CDC)

Hepatitis A virus (HAV) is a 27 nm, non-enveloped, icosahedral, ssRNA virus with a single serovar. So far, 4 different genotypes have been identified in hepatitis A viruses, all belonging to the same serotype.

Genome

The HAV genome is encoded in 7474 nucleotides, which are divided into three regions:

• 5' untranslated region, with 742 nucleotides
• Single reading frame encoding a 2227 amino acid polypeptide, with 6681 nucleotides
• 3' noncoding region, with 63 nucleotides

The reading frame encodes a polypeptide that is processed by a viral protease. This process takes place cotranslationally, and leads to the formation of:

• Four structural proteins
• Seven nonstructural proteins

Tropism

Similarly to other hepatitis viruses, the hepatitis A virus shows tropism for the liver cells. The hepatocytes represent the predominant site for viral replication.

Natural Reservoir

• Humans are the only natural reservoir of the virus.
• There are no insect or animal vectors.
• A chronic HAV carrier state has not been reported.