virology of hepatitis a
TRANSCRIPT
![Page 1: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/1.jpg)
Hepatitis A Virus
• Picornaviridae family• One serotype- stable(protective for life)• Non-enveloped• Single stranded positive• Stable ( ether, acid, heat: 60 c for 1 hr)• Destroyed (autoclaving, boil 5 min, chlorine)
![Page 2: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/2.jpg)
• Feco-oral route• Crowded: early age, high sanitation: older
• Clinical finding• IP: 3-4 weeks• Asymptomatic in children• Life long immunity• No chronicity
![Page 3: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/3.jpg)
![Page 4: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/4.jpg)
Lab investigation
• Detect HAV antibodies- IgM: acute phase (most reliable)- IgG: life long protection• Detect HAV antigen in stool (ELISA)• Detect HAV RNA in stool (PCR, nucleic acid
hybridization)
![Page 5: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/5.jpg)
Prevention and control
• Control food and water• Good hygiene-hand refreshing• Chlorine and proper sewage• Active immunization• Passive immunization
![Page 6: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/6.jpg)
Hepatitis E virus
• Unclassified genus• Feco-oral route, water borne• Endemic in tropical countries• IP: 40 days• HIGH MORTALITY RATE IN PREGNANT WOMAN• No chronicity• Detect anti HEV antibodies and HEV-RNA in serum• Same prevention and control as hepatitis A
![Page 7: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/7.jpg)
Hepatitis B virus
• Hepadnavirus• Icosahendral nucleocapsid• Partially double-stranded circular DNA genome• Outer shell: HBsAg• Inner core: Hbc Ag• Secreted in soluble form: HBeAg• EM of serum: spherical particles, filamentous
particles and complete virions (Dane particle)
![Page 8: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/8.jpg)
Epidemiology and transmission
• High titre are present in blood and serum1. Percutaneous• Blood transfusion• Contaminated syringes and needles• Improperly sterilized instrument• Razor and tooth brush sharing• Needle stick injuries2. Sexual transmission3. Perinatal transmission
![Page 9: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/9.jpg)
Clinical features
• IP: 10-12 weeks• Many asymptomatic• Outcome:• Adult: 90-95% recover completely• Infected infant: chronic carries• Chronic: can lead to cirrhosis, liver failure and death• CHRONIC: HIGH RISK OF HCC • HBV Vaccine
![Page 10: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/10.jpg)
Virologic and serologic events
• First appearance: HBs Ag• Viremic stage: HBV DNA and HBE Ag• HBsAg , appears 2-6 weeks before clinical and
biochemical evidence, throughout the course, disappearr by 6 months after exposure
• Viral replication: IgM specific anti HBc• Window phase: disappearance of Hbs Ag. After
that, antibody to HbsAg is detected• Start of resolution of disease: anti Hbe
![Page 11: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/11.jpg)
![Page 12: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/12.jpg)
Acute phase with recovery
![Page 13: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/13.jpg)
![Page 14: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/14.jpg)
• HBV chronic carriers: Hbs Ag persists for more than 6 months in thepresence of HbeAg or anti-Hbe.
• Low titres of IgM anti-Hbc are found in the sera of most chronic carriers.
• Lab:• ELISA: HBV antigen and antibodies• PCR: HBV DNA
![Page 15: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/15.jpg)
![Page 16: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/16.jpg)
Interpretation of the result
1. serologic: four phase of HBV infection2. Immunization: anti-Hbs3. Transmissibility: HbeAg4. Infectious virion present: Viral DNA
![Page 17: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/17.jpg)
Test acute phase
Window phase
Complete recovery
Chronic carrier state
HBs Ag Positive Negative Negative Positive
Anti-Hbs Negative Negative Positive Negative
Anti-Hbc Positive Positive Positive Positive
![Page 18: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/18.jpg)
Prevention and control
1. Hepatitis B vaccine- Prevent consequence- Dose: 0,1,6- Plasma derived HBs Ag- All infant, health care personnel, on transfusion,
dialysis2. Hepatitis B immunoglobulin (simultenously)- Soon after exposure- Infants to HBV positive mother, exposed person
![Page 19: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/19.jpg)
Hepatitis D virus
• Defective virus, uses Hbs Ag as envelope (HBV is helper virus)
• Blood borne virusTwo types:• Coinfection: both at same time• Superinfection: of chronically infected HBV
![Page 20: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/20.jpg)
Outcome:• Coinfected: more severe that HBV alone, but
incidence of chronic hepatitis is about the same
• Superinfected: much more severe, higher incidence of chronic hepatitis
Lab:• ELISA: HD Ag, IgM and anti HD antibodies• PCR: HD-RNA
![Page 21: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/21.jpg)
Hepatitis C vaccine
• Flaviviridae• 6 genotypes, not correlated with clinical
disease, differ in response to antiviral therepy.• Egypt: 4a• Percutaneous or permucosal
![Page 22: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/22.jpg)
• Appearance of anti-HCV antibodies: 8-9 weeks• HCV RNA: 1-3 weeks after exposure. The
means of diagnosis in seronegative patients• Chronic hepatitis: serum ALT fluctuate
overtime and maybe intermittently normal. HCV RNA may persists for decades
![Page 23: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/23.jpg)
![Page 24: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/24.jpg)
• Outcome: 70-90% chronic HCV infection• Resembles hepatitis B as regards
predisposition to chronic liver disease, cirrhosis and HCC.
• End stage liver disease associated with HCV is most common indication for liver transplantation.
![Page 25: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/25.jpg)
Lab diagnosis
1. ELISA: detect antibodies to HCV, consider:- Early seronegative phase: negative result- Positive: acute, chronic, resolved?- False positive can occur. Confirmed by : RIBA.
If positive, test for viral RNA for active disease.
- Poor serologic response in some patient. Test for HCV RNA.
![Page 26: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/26.jpg)
2. RT-PCR, for derection of HCV RNA- Active disease- Early seronegative- Poor serologic patients
• Acute self limiting: dissappear (resolved)• Measure viral load: response to antiviral
therapy (quantitative PCR)
![Page 27: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/27.jpg)
Hepatitis
• Diffuse inflammation of parenchyma• Causes: • Infective• Metabolic• Autoimmune• Chemicals• drugs
![Page 28: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/28.jpg)
1.Hepatotropic- most common form - A, B, C, D, E, G2. Systemic
![Page 29: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/29.jpg)
Clinicopathological syndromes
1. Subclinical – asymptomatic, any type2. Acute viral hepatitis – any type3. Chronic viral hepatitis – HBV, HCV, HDV.
NEVER HAV and HEV4. Carrier state – mainly HBV. NEVER HAV, HEV5. Fulminant hepatitis – HEV among pregnant
females
![Page 30: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/30.jpg)
Clinical course of acute hepatitis
1. HAV - Most undergo complete recovery2. HBV- Most (>90%) complete recovery- 1-2% chronic hepatitis3. HCV- >70% progress to chronic hepatitis- <30% undergo recovery- Few develop fulminant
![Page 31: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/31.jpg)
4. HDV- coinfection: • 90% undergo recovery• 3-4% develop fulminat• Rare progress to chronic hepatitis- Superinfection• 10-15%: recovery• 80%: chronic hepatitis• 7-10%: fulminant5. HEV- Most undergo complete recovery- Pregnant females: fulminant (20%)- No chronic or carrier state
![Page 32: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/32.jpg)
CHRONIC VIRAL HEPATITIS
• Symptomatic, biochemical, serological evidence of inflammatory hepatic disease with histologically documented without improvement, more than 6 months
• Mainly: HCV >70%, HDV (80% superinfection) and some HBV
![Page 33: Virology of Hepatitis A](https://reader036.vdocuments.us/reader036/viewer/2022062904/577cce261a28ab9e788d73e3/html5/thumbnails/33.jpg)
CARRIER STATE
• Not manifest symptoms, but persistent antigenemia(circulating infectious virus particles), more than 6 months with normal transaminases and no clinical symptoms.
• Mainly: HBV (adults infected by HBV and non-immunized infants born to infected mother)
• Increased risk of HCC