Hepatitis A is an acute viral liver infection caused by HAV and spread mainly by the fecal–oral route.
It is usually self-limited and does not progress to chronic hepatitis.
Children are often asymptomatic, whereas adults more often develop acute icteric hepatitis.
Diagnosis is usually based on clinical suspicion and confirmed by anti-HAV IgM.
Most cases require supportive treatment only.
Important uncommon complications include prolonged cholestatic hepatitis, relapsing hepatitis, and rarely acute liver failure.
Prevention depends on sanitation, safe food and water, and vaccination.
Etiology
HAV is one of the most common causes of acute hepatitis infection worldwide. The discovery of a virus-like antigen in 1973 via immune electron microscopy marked a pivotal advancement in comprehending acute infectious hepatitis, culminating in identifying HAV.Initially categorized as enterovirus type 72, HAV is now classified as the sole member of the Hepatovirus genus within Picornaviridae.[7] Despite sharing structural similarities with insect-infecting picornaviruses and having evolutionary roots in bats, rodents, and shrews, HAV exhibits distinctive features in its life cycle and hepatotropism.
This nonenveloped, icosahedral virus, measuring 27 to 32 nm, is transmitted fecal-orally and displays notable differences in its physical form when excreted versus circulating in the blood. Genomic analysis reveals 6 genotypes, 3 infecting humans and 3 found in primates. Genotype distribution varies geographically, with human infections predominantly involving genotype 1. The HAV genome, a 7.5 kb positive-sense single-stranded ribonucleic acid, contains an internal ribosome entry site, modified capsid proteins, and specific replication elements.
Pathogenesis
• HAV enters the body through the gastrointestinal route and reaches the liver through the bloodstream
• It infects hepatocytes and replicates in the liver
• Liver injury is mainly immune-mediated rather than due to direct viral destruction alone
• The infection is acute and self-limited; chronic infection does not occur
• Virus is excreted in bile and shed in stool, especially in the early phase, which explains fecal–oral transmission
Symptoms
• Often asymptomatic, especially in children
• Fatigue / malaise
• Loss of appetite
• Nausea, vomiting
• Abdominal discomfort
• Dark urine
• Pruritus
• Fever
HAV is one of the most common causes of acute hepatitis infection worldwide. The discovery of a virus-like antigen in 1973 via immune electron microscopy marked a pivotal advancement in comprehending acute infectious hepatitis, culminating in identifying HAV.Initially categorized as enterovirus type 72, HAV is now classified as the sole member of the Hepatovirus genus within Picornaviridae.[7] Despite sharing structural similarities with insect-infecting picornaviruses and having evolutionary roots in bats, rodents, and shrews, HAV exhibits distinctive features in its life cycle and hepatotropism.
This nonenveloped, icosahedral virus, measuring 27 to 32 nm, is transmitted fecal-orally and displays notable differences in its physical form when excreted versus circulating in the blood. Genomic analysis reveals 6 genotypes, 3 infecting humans and 3 found in primates. Genotype distribution varies geographically, with human infections predominantly involving genotype 1. The HAV genome, a 7.5 kb positive-sense single-stranded ribonucleic acid, contains an internal ribosome entry site, modified capsid proteins, and specific replication elements.
• HAV enters the body through the gastrointestinal route and reaches the liver through the bloodstream
• It infects hepatocytes and replicates in the liver
• Liver injury is mainly immune-mediated rather than due to direct viral destruction alone
• The infection is acute and self-limited; chronic infection does not occur
• Virus is excreted in bile and shed in stool, especially in the early phase, which explains fecal–oral transmission
Hepatitis A is an acute viral liver infection caused by HAV and spread mainly by the fecal–oral route.
It is usually self-limited and does not progress to chronic hepatitis.
Children are often asymptomatic, whereas adults more often develop acute icteric hepatitis.
Diagnosis is usually based on clinical suspicion and confirmed by anti-HAV IgM.
Most cases require supportive treatment only.
Important uncommon complications include prolonged cholestatic hepatitis, relapsing hepatitis, and rarely acute liver failure.
Prevention depends on sanitation, safe food and water, and vaccination.
• Often asymptomatic, especially in children
• Fatigue / malaise
• Loss of appetite
• Nausea, vomiting
• Abdominal discomfort
• Dark urine
• Pruritus
• Fever
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