Hepatitis a, e, b

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Viral hepatitis is a systemic disease primarily involving the liver.
Hepatotropic viruses : liver is the target organ and the main site of virus replication
Hepatitis A virus (HAV)
hepatitis B virus (HBV)
Hepatitis C virus (HCV)
Hepatitis D virus (HDV, delta virus)
Hepatitis E virus (HEV).

Enterically:
virus is spread from person-to-person by putting something in the mouth that has been contaminated with the stool of a person with hepatitis E. This type of transmission is called "fecal-oral." For this reason, the virus is more easily spread in areas where there are poor sanitary conditions

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  • Enterically: virus is spread from person-to-person by putting something in the mouth that has been contaminated with the stool of a person with hepatitis E. This type of transmission is called "fecal-oral." For this reason, the virus is more easily spread in areas where there are poor sanitary conditions.
  • An autoclave is a device used to sterilize equipment and supplies by subjecting them to high pressure saturated steam at 121 °C for around 15–20 minutes depending on the size of the load and the contents
  • 9 Following exposure to HAV , Virus particles are found in the stools from about 2 -3 weeks before the onset of jaundice During the acute stage of the infection, the liver enzyme alanine transferase (ALT) is present in the blood at levels much higher than is normal. The enzyme comes from the liver cells that have been damaged by the virus Anti HAV IgM appears during the acute phase and declines to undetectable levels within 3 – 6 months Anti HAV IgG appears later and gives life long protection
  • The outer shell or enveloppe is host cell derived and contains a protein called hepatitis B surface antigen ( HBsAg) The inner core ( nucleocapsid) is composed of the core protein ( HBcAg) and encloses the viral genome associated with viral DNA polymerase Another core antigen known as HBeAg is secreted in a soluble form
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  • Hepatitis a, e, b

    1. 1.  Viral hepatitis is a systemic disease primarily involving the liver.Hepatotropic viruses : liver is the target organ and the main site of virus replication• Hepatitis A virus (HAV)• hepatitis B virus (HBV)• Hepatitis C virus (HCV)• Hepatitis D virus (HDV, delta virus)• Hepatitis E virus (HEV).
    2. 2.  Other viruses also infect other sites of the body, and therefore are not exclusively hepatitis viruses. • Yellow fever virus. • Epstein-barr virus. • Cytomegalovirus.
    3. 3.  The clinical manifestations of hepatitis are the same, regardless of which virus is the cause.is characterized by: Fever+ gastrointestinal symptoms ( anorexia, nausea, vomiting) + Jaundice No jaundice ↓ ↓ icteric hepatitis anicteric hepatitis (is more common).
    4. 4. Hepatotropic virusesTransmitted enterically Transmitted parenterally -Intravenous routevirus is transmitted by contaminated food Intramuscular routeand water: Subcutaneous route Intradermal route HAV and HEV HCV, HBV and HDV
    5. 5. Enterically transmitted hepatitis viruses Hepatitis A virusClassification • Family: Picornaviridae • Genus: hepatovirus • Only one serotype is known
    6. 6. Properties• Icosahedral nucleocapsid.• Nonenveloped.• Genome: a single stranded RNA.• The virus is stable to treatment with ether, acid and heat (60°C for 1 hour).• It can be destroyed by autoclaving) to sterilize)boiling for 5 min, or by chlorine.
    7. 7. Hepatitis A Virus
    8. 8. Transmission and epidemiologyHAV is transmitted by the fecal-oral route.• Under crowded conditions and poor sanitation, infection occurs at an early age, most children become immune by age 10.• With higher levels of poor sanitation, infection occurs in older persons.
    9. 9. Clinical findings IP: 3-4 weeks Clinical illness: • Asymptomatic infection is common in infants and children. • Disease is more severe in adults. (is symptomatic infection) Outcome of infection: Almost all cases (99%) recover completely in 2-4 weeks with life long immunity( no repeat infection) There is no chronicity.
    10. 10. 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, where it multiplies within hepatocytes and Kupffer cells (liver macrophages).• Virions are secreted into the bile and released in stool.• HAV is excreted in large quantities approximately 15 days prior to appearance of symptoms or anti- HAV IgM antibodies in the blood
    11. 11. Hepatitis A Infection Typical Serological Course Symptoms Total anti- HAVTitre ALT Fecal HAV IgM anti-HAV 0 1 2 3 4 5 6 1 2 2 4 Months after exposure
    12. 12. Laboratory diagnosis Detection of HAV antibodies: • Anti-HAV IgM → acute hepatitis A • Anti-HAV IgG → past infection or vaccination. • ELISA is the method of choice for detecting these antibodies. Detection of HAV antigen: In stools by ELISA. Detection of HAV RNA: In stools by PCR and nucleic acid hybridization.
    13. 13. Prevention and control Prevention of fecal contamination of food and water. Good hygiene-hand washing. Chlorination of water
    14. 14. Active immunization  A formalin inactivated HAV vaccine IS AVAILABLE • Safe and effective • Recommended for use in persons over 1 year of age. • Two doses should be given: an initial dose , booster dose 6-12 months later. Passive immunization  Immune (gamma) globulin confers passive protection when given 1-2 weeks after exposure to hepatitis A.Immune globulin does not prevent the infection but makes it mild or subclinical.
    15. 15. Hepatitis E virusProperties The virus is a small. Non enveloped. Single stranded RNA virus.
    16. 16. Transmission HEV is transmitted enterically.Clinical findings IP: ~ 40 days The disease resembles hepatitis A. WITH EXCEPTION of A high mortality rate in pregnant women (fulminant hepatitis). Chronic liver disease does not occur.
    17. 17. DiagnosisDetection of:  Anti-HEV antibodies.  HEV-RNA in serum.Prevention and control  General measures as with hepatitis A.  There is no vaccine.
    18. 18. Parenterally-transmitted hepatitis viruses Hepatitis B virusProperties Member of the hepadnavirus family. 42 nm enveloped virion. Icosahedral nucleocapsid containing a partially double-stranded circular DNA genome.
    19. 19. Electron microscopy of a patient s serum reveals three different types of particles These two forms are made up exclusively of surface antigen *The virus is one of the smallest enveloped animal viruses, butpleomorphic forms exist
    20. 20. Hepatitis B Virus
    21. 21. Pathogenesis• Although replication takes place in the liver, the virus spreads to the blood where viral proteins and antibodies against them are found in infected people.
    22. 22. Epidemiology and Transmission HBV is worldwide in distribution. Egypt lies within the zone of moderate prevalence of chronic carriers (2-7% of the population is HBsAg positive). High titers of the virus: blood and serum. Moderate levels: semen, saliva and vaginal secretion.
    23. 23. Geographic Distribution of Chronic HBV Infection HBsAg Prevalence ≥8% - High 2-7% - Intermediate <2% - Low
    24. 24. Three main modes of transmission.1-Percutaneous and permucosal exposure to blood.2- Sexual transmission.3- Perinatal transmission.
    25. 25. 1-Percutaneous and permucosal exposure to blood.  Transfusion of blood and blood products.  Sharing of contaminated needles and syringes.  The use of improperly sterilized instruments (even in tattooing and ear piercing).  Sharing of razors and tooth brushes.2- Sexual transmission.3- Perinatal transmission from mother to newborn.  During birth or breast feeding.  In-utero transmission is rare.
    26. 26. Clinical features The mean incubation period is 10-12 weeks. Many HBV infections are asymptomatic. Symptoms are similar to that of hepatitis A, but tend to be more severe. Outcome of infection Adults Infants and young children ↓ ↓ 90-95% recover completely. 80-95% chronic carriers.
    27. 27. Spectrum of chronic hepatitis B diseases Most chronic carriers are asymptomatic. Some develop chronic hepatitis → cirrhosis, liver failure and death. Chronic carriers are at high risk of developing hepatocellular carcinoma, especially those infected as infants. HBV vaccine is the first vaccine to prevent a human cancer.
    28. 28. Virologic and serologic events following exposure to HBV
    29. 29. Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Symptoms HBeAg anti-HBe Total anti-HBc Titer HBsAg IgM anti-HBc anti-HBs 0 4 8 12 16 20 24 28 32 36 52 100 Weeks after Exposure
    30. 30. Progression to Chronic Hepatitis B Virus Infection Typical Serologic Course Acute Chronic (6 months) (Years) HBeAg anti-HBe HBsAg Total anti- HBc Titer IgM anti-HBc 0 4 8 12 16 20 24 28 32 36 52 Years Weeks after Exposure
    31. 31. Laboratory diagnosis HBV antigen and antibodies are usually detected in serum by ELISA. HBV DNA is detected by PCR.
    32. 32. Interpretation of results Serologic tests can identify four stages of HBV infection. Test Acute Window Complete Chronic disease phase recovery carrier state HBsAg Positive Negative Negative Positive Anti-HBs Negative Negative Positive Negative Anti-HBc Positive Positive Positive Positive
    33. 33.  Persons immunized with HBV vaccine have anti-HBs but not anti-HBc because the vaccine is purified HBsAg. The presence of HBeAg → high probability of transmissibility. The presence of anti-HBe → lower probability, but transmission can still occur. The detection of viral DNA in the serum is strong evidence that infectious virions are present.
    34. 34. Prevention and controlI-Hepatitis B vaccination is the most effective measure to prevent HBV and its consequences.1 .Plasma derived vaccine:Purified HBsAg from healthy HBsAg positive carriers.2. Recombinant DNA derived vaccine:HBsAg produced in yeast cells by recombinant DNA techniques.
    35. 35. The vaccine is recommended for: 1. All infants as part of their regular immunization schedule.2. Heath care personnel frequently exposed to blood or blood products. 3. Patients receiving multiple transfusions or dialysis. The vaccine is given in a three-dose regimen 0, 1, 6 months.
    36. 36. II-Hepatitis B immune globulin (HBIG) is used toprovide immediate, passive protection if it is givensoon after exposure.Both the vaccine and HBIG should be administeredsimultaneously (at different sites) to:  Persons exposed to HBV percutaneously or by contamination of mucosal surfaces.  Infants born to HBV-positive mothers. Both immediate and long term protection areprovided.
    37. 37. III-General measures1. All blood for transfusion should be screened for HBV.2. Proper sterilization of endoscopes and surgical instruments.3. Only disposable needles and syringes should be used.4. Standard precautions to prevent percutaneous injuries or contact of non intact skin or mucous membrane with blood or body fluids:  Gloves should be worn when handling potentially infectious material.  Proper handling and disposal of sharps.  Decontamination of spillage accidents with chlorine.
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