Hepatitis A Virus ( HAV )

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Hepatitis A Virus ( HAV ) : 

Hepatitis A Virus ( HAV ) Prepared By: Rania Tawfik Abdulhafez Supervision by : Prof. Gamal El Sawaf

Enterically transmitted hepatitis : 

Enterically transmitted hepatitis Caused by:- Hepatitis A virus Hepatitis E virus Self- limiting viral infections Vary from subclinical to acute Both viruses spread via fecal contaminated food and water Spread controlled by improvement of the sanitary system and personal hygiene

Hepatitis A virusDiscovery &General properties : 

Hepatitis A virusDiscovery &General properties 1973 Enteric ally transmitted hepatitis Infectious hepatitis 27-28 nm SSRNA , Icosahedral Non-enveloped

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Stable @pH 3x3hrs@RT Stable@56ºCx30 min Stable for several wks @RT Completely inactive@70 ºCx4min Instant inactive@85ºC Reliable inactivation (121ºCx30min) Inactive: hypochlorite 1.5-2.5mg/l for 15 min Inactive: 2% gluteraldehyde Inactive: 3% formalin Resistant to organic solvent: diethyl ether, tri-chloro- & tri-floroethane

Clinical course/pathogenesis : 

Clinical course/pathogenesis Following ingestion, HAV enters the bloodstream through the epithelium of the oropharynx or intestine. The blood carries the virus to its target, the liver, and multiplies within hepatocytes and Kupffer cells (i.e., liver macrophages). There is no apparent virus-mediated cytotoxicity, and liver pathology is likely immune-mediated. Virions are secreted into the bile and released in stool. HAV is excreted in large quantities approximately 11 days prior to appearance of symptoms or anti-HAV IgM antibodies in the blood. The incubation period is 15-50 days, and mortality is less than 0.5%.

Clinical course/pathogenesis : 

Clinical course/pathogenesis Incubation period: 2-6wk Viral excretion may precede jaundice symptoms Cease near time of Jaundice onset Jaundice onset about time of IgG & IgM IgM decline over 3-6 months IgG life long

Slide 8: 

Prodromal: Anorexia- Nausea-Vomiting – Jaundice Specific: Dark urine, Clay-coloured stool Discoloration of :Skin, Sclera, Mucous membrane Resolution: return of colour to stool

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