Diese Präsentation wurde erfolgreich gemeldet.
Wir verwenden Ihre LinkedIn Profilangaben und Informationen zu Ihren Aktivitäten, um Anzeigen zu personalisieren und Ihnen relevantere Inhalte anzuzeigen. Sie können Ihre Anzeigeneinstellungen jederzeit ändern.

Lecture 8a - HAV-HEV-HGV-RMC

2.073 Aufrufe

Veröffentlicht am


Veröffentlicht in: Gesundheit & Medizin
  • Als Erste(r) kommentieren

Lecture 8a - HAV-HEV-HGV-RMC

  1. 1. •Family Picornaviridae •Non-enveloped •Icosahedral Hepatitis A Virus (HAV)
  2. 2. Genome Replication • HAV can not be propagated in the laboratory as readily as other enteroviruses • The virus interacts with receptors expressed on liver cells • Is not cytolytic and is released from liver cells by exocytosis. HAV : Properties of Virion
  3. 3. Resistance HAV is resistant to • Detergents • Acids • Temperature up to 60o C • Can survive for many months in fresh and salt water HAV : Properties of Virion
  4. 4. Routes of Transmission Main Route : fecal-oral • The virus is excreted into stool in high concentrations • Spreads by: ° Contaminated water & food ° Dirty hands Other Routes • Transfusion of blood and blood products during viremia • I.V drug abuse HAV : Epidemiology
  5. 5. Transmission • Most infected people are contagious before symptoms • Outbreaks usually originate from a common source like: ° Water supply ° Restaurant ° Daycare units • Higher incidence of HAV infection is directly related to: ° Poor hygienic conditions & ° Over-crowding. HAV : Epidemiology
  6. 6. Seroprevalence •Mostly children are infected •Have mild illness •Develop lifelong immune protection against re-infection HAV : Epidemiology
  7. 7. HAV : Clinical Features Incubation period • Between 3-5 weeks Clinical features • Many infections are asymptomatic • Initial symptoms include fever, fatigue, nausea, loss of appetite and abdominal pain • Jaundice is common • HAV is nearly always self limiting • Complications such as fulminant hepatitis are rare • Mortality : about 1/1000
  8. 8. HAV : Diagnosis • Clinical symptoms • The identification of a known infected source • Immune electron microscopy for HAV feces • HAV IgM & IgG measured by ELISA or RIA • Clinical symptoms • The identification of a known infected source • Immune electron microscopy for HAV feces • HAV IgM & IgG measured by ELISA or RIA
  9. 9. HAV : Prevention and control • Proper hygienic measures IMMUNIZATION A. Passive immunization • Immunoglobulins : Given before or shortly after exposure • Can prevent infection in the next 3-6 months B. Active immunization with Hepatitis A vaccine • There is only one serotype of HAV • A killed HAV vaccine is available  Routine hepatitis A vaccination for children aged 12 to 23 months and for adults who are at high risk for infection.
  10. 10. Hepatitis E Virus (HEV) Taxonomy and structure • Belongs to family Caliciviridae. Epidemiology and control • World-wide distribution • Predominantly spreads by fecal-oral route • Especially through contaminated water
  11. 11. HEV : Pathogenesis & Clinical Syndromes • Are similar to that of HAV • Causes only acute disease • Incubation period is longer • HEV infection is specially serious in pregnant women with a mortality rate of 20%
  12. 12. Hepatitis G Virus (HGV) • Resembles HCV in many aspects • Belongs to the family Flaviviridae • Probably has a predilection for chronic disease • So far, HGV infection can only be diagnosed by detection of genome by PCR.