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Hepatitis ppt final

Hepatitis viruses include hepatitis A, B, C, D, and E. Hepatitis A virus is transmitted through the fecal-oral route while hepatitis B, C, and D are transmitted through blood and body fluids. Hepatitis B and C can cause chronic infections while hepatitis A usually does not. Diagnosis involves tests to detect viral antigens, antibodies, and nucleic acids. Treatment options depend on the hepatitis virus but may include antiviral drugs and vaccines to prevent transmission.

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1 HEPATITIS VIRUSES By Dr.D.W.Deshkar Assistant Professor Dept. of Microbiology D.Y.Patil Medical College,Kolhapur
2 What is Viral Hepatitis ? • Viral hepatitis is a systemic disease with primary inflammation of the liver by any one of a heterogenous group of hepatotropic viruses
3 HEPATITIS VIRUSES • Hepatitis A (HAV) Picornaviridae (1973) • Hepatitis B (HBV) Hepadnaviridae (1970) • Hepatitis C (HCV) Flaviviridae (1988) • Hepatitis D (HDV) ? (1977) • Hepatitis E (HEV) (Caliciviridae) (1983), Hepeviridae • Hepatitis F – Not separate entity – Mutant of B Virus.
4 Viral Hepatitis - Historical Perspectives “Infectious” AA Viral hepatitis NA:NBNA:NB E Enterically transmitted “Serum” B D C Parenterally transmitted F- Mutant Of B G
5 Type of Hepatitis A B C D E Source of virus Feces Blood Blood derived Body fluids Blood Blood derived Body fluids Blood Blood derived Body fluids Feces Route of Transmission Feco-oral Percutaneous Permucosal Percutaneous Permucosal Percutaneous Permucosal Feco- oral Chronic Infection No Yes Yes Yes No Prevention Pre Post Exposure Immunization Pre Post Exposure Immunization Blood donor screening Blood donor screening Pre Post Exposure Immunization Ensure Safe Drinking water
6 HAV
7 Hepatitis A Virus Naked RNA virus Related to enteroviruses, formerly known as Enterovirus 72, now put in its own family: heptoviridae One stable serotype only Difficult to grow in cell culture: primary marmoset cell culture and also in vivo in chimpanzees and marmosets 4 genotypes exist, but in practice most of them are group 1 RNA
8 RESISTANCE ( HAV) • Resistant to inactivation by heat at 600 C for one hour, ether & acid at pH 3. • Inactivated by boiling for one minute, 1: 4,000 formaldehyde at 370 C for 72 hours & chlorine 1 ppm for 30 minutes. • Not affected by anionic detergents. • Survives prolonged storage at 40 C or below.
9 Hepatitis A Virus Transmission • Close personal contact (e.g., household contact, sex contact, child day care centers) • Contaminated food, water (e.g., infected food handlers, raw shellfish) • Blood exposure (rare) (e.g., injecting drug use, transfusion)
10 Prodromal or Preicteric phase : (symptoms: fatigue, joint- and abdominal pain, malaise, vomiting, lack of appetite, hepatomegaly) Icteric phase: Icterus: jaundice (skin, sclera, mucous membranes, cause: elevated bilirubin level, bilirubinuria: dark urine, pale stool)
11 PATHOGENESIS - HAV Cause subacute disease in children & young adults. HAV invade into human body by fecal-oral route, multiplies in the intestinal epithelium & reaches the liver by hematogenous spread. After one week, the HAV reach liver cells replicate within.Then enter intestine with bile and appear in feces. Incubation Period : 2 to 6 weeks.
12 PATHOGENESIS – HAV contd-- – After HAV replicating and discharging,liver cells damage begin – Animal experiment proved that immune complex may attend the pathogenesis of HAV – Complement level reduce the pathogenesis maybe following: – activated T cell secrete γ-INF that promote the representation of HLA on the liver cells,CTL may kill the target cell infected with HAV
13 LAB.DIAGNOSIS 1. Demonstration of Virus in feces: By: Immunoelectron microscopy 2. Virus Isolation: 3. Detection of Antibody :By ELISA 4. Biochemical tests: i) Alanine aminotransferase (ALT) ii) Bilirubin iii) Protein 5. Molecular Diagnosis : RT PCR of feces
14 Fecal HAV Symptoms 0 1 2 3 4 5 6 1 2 2 4 Hepatitis A Infection IgG anti-HAV Titre ALT IgM anti-HAV Months after exposure Typical Serological Course
15 • Many cases occur in community-wide outbreaks – no risk factor identified for most cases – highest attack rates in 5-14 year olds – children serve as reservoir of infection • Persons at increased risk of infection – travelers – homosexual men – injecting drug users Hepatitis A Vaccination Strategies Epidemiologic Considerations
16 Hepatitis B Virus
17 Hepatitis B VirusHepatitis B Virus
18 1 、 Properties of HBV • a member of the hepadnavirus group • Circular partially double-stranded DNA viruses • Replication involves a reverse transcriptase. • endemic in the human population and hyperendemic in many parts of the world. • a number of variants • It has not yet been possible to propogate the virus in cell culture
19 HBVHBV : Structure: Structure
20 HBV : Structure • Virion also referred to as Dane particle (ds-tranded DNA) • 42nm enveloped virus • Core antigens located in the center (nucleocapsid) * Core antigen (HBcAg) * e antigen (HBeAg)- an indicator of transmissibility (minor component of the core- antigenically distinct from HBcAg) • 22nm spheres and filaments other forms- no DNA in these forms so they are not infectious (composed of surface antigen)- these forms outnumber the actual virions
21 HBV Structure & Antigens Dane particleDane particle HBsAg = surface (coat) protein ( 4 phenotypes : adw, adr, ayw and ayr) HBcAg = inner core protein (a single serotype) HBeAg = secreted protein; function unknown
22 decoy particles • HBsAg-containing particles are released into the serum of infected people and outnumber the actual virions. • Spherical or filamentous • They are immunogenic and were processed into the first commercial vaccine against HBV.
23 GENOME
24 There are 4 open reading frames derived from the same strand (the incomplete + strand) • S - the 3 polypeptides of the surface antigen (preS1, preS2 and S - produced from alternative translation start sites. • C - the core protein • P - the polymerase • X - a transactivator of viral transcription (and cellular genes?). HBx is conserved in all mammalian (but not avian) hepadnaviruses. Though not essential in transfected cells, it is required for infection in vivo. Open Reading Frames
25 HBx activates the Ras-Raf-MAPK cascade: Influence on cell proliferation?  HBx-mediated activation of the Ras-Raf-MAPK pathway has been linked to accelerated entry of cells into S phase  Unlike the magnitude of Ras activation by growth factors, HBx stimulation is modest but sustained  Downstream signaling: activate transcription factors (eg. AP-1, NF-ΚB and c-myc)  Activation of the Ras-Raf-MAPK signaling pathway is essential for HBx activation of AP-1 and NF-ΚB
26 2 、 HBV: Replication • Reverse transcription: one of the mRNAs is replicated with a reverse transcriptase making the DNA that will eventually be the core of the progeny virion • RNA intermediate: HBV replicates through an RNA intermediate and produces and release antigenic decoy particles. • Integration: Some DNA integrates into host genome causing carrier state
27 Replication of HBV
28  Parenteral - IV drug abusers, health workers are at increased risk.  Sexual - sex workers and homosexuals are particular at risk.  Perinatal (Vertical) – mother (HBeAg+) →infant. 33 、、 HBV:HBV: Modes of TransmissionModes of Transmission
29 4 、 Epidemiology • 350,000,000 carriers worldwide • 120,000,000 carriers in China - the carrier rate can exceed 10% -15 to 25% of chronically infected patients will die from chronic liver disease • 500,000 deaths/year in China • 982,297 liver disease in China 2005 • 50% of children born to mothers with chronic HBV in the US are Asian American
30 High Moderate Low/Not Detectable blood semen urine serum vaginal fluid feces wound exudates saliva sweat tears Breast milk Concentration of Hepatitis B Virus in Various Body Fluids 伤口渗出液 唾液 精液 阴道分泌液
31 High-risk groups for HBV infection • People from endemic regions • Babies of mothers with chronic HBV • Intravenous drug abusers • People with multiple sex partners • Hemophiliacs and other patients requiting blood and blood product treatments • Health care personnel who have contact with blood • Residents and staff members of institutions for the mentally retarded
32 Symptoms HBe Ag anti- HBe Total anti- HBc IgM anti- HBc anti- HBsHBs Ag 0 4 8 12 16 20 24 28 32 36 52 100 Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Weeks after Exposure Titre
33 5 、 Pathogenesis & Immunity • Virus enters hepatocytes via blood • Immune response (cytotoxic T cell) to viral antigens expressed on hepatocyte cell surface responsible for clinical syndrome • 5 % become chronic carriers (HBsAg> 6 months) • Higher rate of hepatocellular ca in chronic carriers, especially those who are “e” antigen positive • Hepatitis B surface antibody likely confers lifelong immunity (IgG anti-HBs) • Hepatitis B e Ab indicates low transmissibility
34 6 、 Clinical Features Incubation period: Average 60-90 days Range 45-180 days Insidious onset of symptoms. Tends to cause a more severe disease than Hepatitis A. Clinical illness (jaundice): <5 yrs, <10% ≥ 5 yrs, 30%-50% 1/3 adults-no symptoms Clinical Illness at presentation 10 - 15% Acute case-fatality rate: 0.5%-1% Chronic infection: < 5 yrs, 30%-90% ≥ 5 yrs, 2%-10% More likely in asymptomatic infections Premature mortality from chronic liver disease: 15%-25%
35 Possible Outcomes of HBV InfectionPossible Outcomes of HBV Infection Acute hepatitis B infection Chronic HBV infection 3-5% of adult- acquired infections 95% of infant- acquired infections Cirrhosis Chronic hepatitis 12-25% in 5 years Liver failureHepatocellular carcinoma Liver transplant 6-15% in 5 years 20-23% in 5 years DeathDeath
36 7 、 Laboratory Diagnosis
37 Diagnosis • A battery of serological tests are used for the diagnosis of acute and chronic hepatitis B infection. • HBsAg - used as a general marker of infection. • HBsAb - used to document recovery and/or immunity to HBV infection. • anti-HBc IgM - marker of acute infection. • anti-HBcIgG - past or chronic infection. • HBeAg - indicates active replication of virus and therefore infectiveness. • Anti-Hbe - virus no longer replicating. However, the patient can still be positive for HBsAg which is made by integrated HBV. • HBV-DNA - indicates active replication of virus, more accurate than HBeAg especially in cases of escape mutants. Used mainly for monitoring response to therapy.
38 、 Current Treatment Options • Interferon alfa (Intron A) （干扰 素） Response rate is 30 to 40%. • Lamivudine (Epivir HBV) （拉米呋啶） (relapse ,drug resistance) • Adefovir dipivoxil (Hepsera) （阿德福韦酯）
39 Treatment • Interferon - for HBeAg +ve carriers with chronic active hepatitis. Response rate is 30 to 40%. – alpha-interferon 2b (original) – alpha-interferon 2a (newer, claims to be more efficacious and efficient) • Lamivudine - a nucleoside analogue reverse transcriptase inhibitor. Well tolerated, most patients will respond favorably. However, tendency to relapse on cessation of treatment. Another problem is the rapid emergence of drug resistance. • Adefovir – less likely to develop resistance than Lamivudine and may be used to treat Lamivudine resistance HBV. However more expensive and toxic • Entecavir – most powerful antiviral known, similar to Adefovir • Successful response to treatment will result in the disappearance of HBsAg, HBV-DNA, and seroconversion to HBeAg.
40 、 Prevention • Vaccination - highly effective recombinant vaccines • Hepatitis B Immunoglobulin (HBIG) -exposed within 48 hours of the incident/ neonates whose mothers are HBsAg and HBeAg positive. • Other measures -screening of blood donors, blood and body fluid precautions.
41 Prevention • Vaccination - highly effective recombinant vaccines are now available. Vaccine can be given to those who are at increased risk of HBV infection such as health care workers. It is also given routinely to neonates as universal vaccination in many countries. • Hepatitis B Immunoglobulin - HBIG may be used to protect persons who are exposed to hepatitis B. It is particular efficacious within 48 hours of the incident. It may also be given to neonates who are at increased risk of contracting hepatitis B i.e. whose mothers are HBsAg and HBeAg positive. • Other measures - screening of blood donors, blood and body fluid precautions.
42 Hepatitis B Vaccine • Infants: several options that depend on status of the mother – If mother HBsAg negative: birth, 1-2m,6-18m – If mother HBsAg positive: vaccine and Hep B immune globulin within 12 hours of birth, 1-2m, <6m • Adults * 0,1, 6 months • Vaccine recommended in – All those aged 0-18 – Those at high risk
43 HEPATITIS C VIRION: spherical, icosahedral, NUCLEIC ACID: ss (+) RNA
44 hypervariable region capsid envelope protein protease/ helicase RNA- dependent RNA polymerase c22 5’ cor e E1 E2 NS 2 NS 3 33c NS 4 c-100 NS 5 3’ Hepatitis C Virus
45 Hepatitis C Virus Genome resembled that of a flavivirus positive stranded RNA genome of around 10,000 bases 1 single reading frame, structural genes at the 5' end, the non-structural genes at the 3' end. enveloped virus, virion thought to 30-60nm in diameter  morphological structure remains unknown HCV has been classified into a total of six genotypes (type 1 to 6) on the basis of phylogenetic analysis Genotype 1 and 4 has a poorer prognosis and response to interferon therapy In Hong Kong, genotype 1 accounts for around 67% of cases and genotype 6 around 25%.
46 HCV replicates exclusively in the cytoplasm via an RNA intermediate Nucleus Viral entry & uncoating Translation & processing (+) (+) (-) (+) HCV RNA replicationVirus particle assembly Replicative intermediate
47 Incubation period: Average 6-7 wks Range 2-26 wks Clinical illness (jaundice): 30-40% (20- 30%) Chronic hepatitis: 70% Persistent infection: 85-100% Immunity: No protective antibody response identified Hepatitis C - Clinical Features
48 Chronic Hepatitis C Infection • The spectrum of chronic hepatitis C infection is essentially the same as chronic hepatitis B infection. • All the manifestations of chronic hepatitis B infection may be seen, albeit with a lower frequency i.e. chronic persistent hepatitis, chronic active hepatitis, cirrhosis, and hepatocellular carcinoma.
49 Symptoms anti- HCV ALT Normal 0 1 2 3 4 5 6 1 2 3 4 Hepatitis C Virus Infection Typical Serologic Course Titre Months Years Time after Exposure
50  Transfusion or transplant from infected donor  Injecting drug use  Hemodialysis (yrs on treatment)  Accidental injuries with needles/sharps  Sexual/household exposure to anti-HCV-positive contact  Multiple sex partners  Birth to HCV-infected mother Risk Factors Associated with Transmission of HCV
51 Laboratory Diagnosis • HCV antibody - generally used to diagnose hepatitis C infection. Not useful in the acute phase as it takes at least 4 weeks after infection before antibody appears. • HCV-RNA - various techniques are available e.g. PCR and branched DNA. May be used to diagnose HCV infection in the acute phase. However, its main use is in monitoring the response to antiviral therapy. • HCV-antigen - an EIA for HCV antigen is available. It is used in the same capacity as HCV-RNA tests but is much easier to carry out.
52 HCV RNA (PCR testing) 􀂄 Virus load 􀂄 Lower detection limit can be 10-615 IU/ml 􀂄 NOT a predictor of disease severity: a high viral load does not mean the liver disease is more severe, and a low viral load does not mean the patient is ok and does not need therapy! 􀂄 Helps predict response rate to treatment (lower means a higher chance of cure with therapy) 􀂄 Used to monitor response during treatment
53 Prognostic Tests • Genotyping – genotype 1 and 4 have a worse prognosis overall and respond poorly to interferon therapy. A number of commercial and in-house assays are available. – Genotypic methods – DNA sequencing, PCR- hybridization e.g. INNO-LIPA. – Serotyping – particularly useful when the patient does not have detectable RNA. • Viral Load – patients with high viral load are thought to have a poorer prognosis. Viral load is also used for monitoring response to IFN therapy. A number of commercial and in-house tests are available.
54 Treatment • Interferon - may be considered for patients with chronic active hepatitis. The response rate is around 50% but 50% of responders will relapse upon withdrawal of treatment. • Ribavirin - there is less experience with ribavirin than interferon. However, recent studies suggest that a combination of interferon and ribavirin is more effective than interferon alone.
55 OUTCOMES of HCV hepatitis
56  Screening of blood, organ, tissue donors  High-risk behavior modification  Blood and body fluid precautions Prevention of Hepatitis C
57 HBsAg RNA δ antigen Hepatitis D (Delta) Virus
58 Hepatitis Delta Virion From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia,, Figure 66-14
59 HEPATITIS D VIRUS (HDV, DELTA AGENT) VIRION: spherical, 36-38 nm, HBV capsid, HDV nucleoprotein NUCLEIC ACID: (-) ss RNA, circular Satellite virus : replicates only in the presence of HBV
60 Hepatitis D Virus • The delta agent is a defective virus which shows similarities with the viroids in plants. • The agent consists of a particle 35 nm in diameter consisting of the delta antigen surrounded by an outer coat of HBsAg. • The genome of the virus is very small and consists of a single-stranded RNA
61 The HDV genome Figure 88-4 Structure of the HDV RNA Genome. The single-stranded circular RNA genome is indicated by the heavy black continuous line. The genome has the ability to form an unbranched rod structure, in which approximately 70% of the bases are engaged in Watson-Crick pairs with counterparts from the opposite side of the circular RNA. In this unbranched rod structure, the region encoding HDAg (nt 1598-957) is on one side. The RNA editing site is at position 1012 in the antigenome. The region on the right-hand side contains the autocatalytic cleavage sites (ribozymes), one in the genome (nt 686) and the other in the antigenome (nt 900). The genome binds HDAg and is transcribed by a host DNA–dependent RNA polymerase. Fields Virology 4th edition, 2002, Chapter 88, Lippincott, Williams and Wilkins, 2002 Fig. 88-4
62  Coinfection – severe acute disease. – low risk of chronic infection.  Superinfection – usually develop chronic HDV infection. – high risk of severe chronic liver disease. – may present as an acute hepatitis. Hepatitis D - Clinical Features
63 Consequences of hepatitis B and delta virus infection Figure 66-15. Consequences of deltavirus infection. Deltavirus (d) requires the presence of hepatitis B virus (HBV) infection. Superinfection of a person already infected with HBV (carrier) causes more rapid, severe progression than co-infection (shorter arrow). From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia.
64  Percutaneous exposures injecting drug use  Permucosal exposures sex contact Hepatitis D Virus Modes of Transmission
65 anti-HBs Symptoms ALT Elevated Total anti-HDV IgM anti-HDV HDV RNA HBsAg HBV - HDV Coinfection Typical Serologic Course Time after Exposure Titre
66 Jaundice Symptoms ALT Total anti-HDV IgM anti-HDV HDV RNA HBsAg HBV – HDV SuperinfectionTypical Serologic Course Time after Exposure Titre
67  HBV-HDV Coinfection Pre or post exposure prophylaxis to prevent HBV infection.  HBV-HDV Superinfection Education to reduce risk behaviors among persons with chronic HBV infection. Hepatitis D - Prevention
68 Hepatitis E Virus
69 Hepatitis E Virus • Calicivirus-like viruses • unenveloped RNA virus, 32-34nm in diameter • +ve stranded RNA genome, 7.6 kb in size. • very labile and sensitive • Can only be cultured recently
70  Incubation period: Average 40 days Range 15-60 days  Case-fatality rate: Overall, 1%-3% Pregnant women, 15%-25%  Illness severity: Increased with age  Chronic sequelae: None identified Hepatitis E - Clinical Features
71 Symptoms ALT IgG anti-HEV IgM anti-HEV Virus in stool 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Hepatitis E Virus Infection Typical Serologic Course Titer Weeks after Exposure
72  Most outbreaks associated with faecally contaminated drinking water.  Several other large epidemics have occurred since in the Indian subcontinent and the USSR, China, Africa and Mexico.  In the United States and other nonendemic areas, where outbreaks of hepatitis E have not been documented to occur, a low prevalence of anti-HEV (<2%) has been found in healthy populations. The source of infection for these persons is unknown.  Minimal person-to-person transmission. Hepatitis E - Epidemiologic Features
73  Avoid drinking water (and beverages with ice) of unknown purity, uncooked shellfish, and uncooked fruit/vegetables not peeled or prepared by traveler.  IG prepared from donors in Western countries does not prevent infection.  Unknown efficacy of IG prepared from donors in endemic areas.  Vaccine? Prevention and Control Measures for Travelers to HEV-Endemic Regions
74 HEPATITIS G VÍRUS FLAVIRUS: similar morphology and genome ◊ in risk groups: acute, chronic and fulminant hepatitis ◊ transmission: blood (mother- newborn babies) ◊ prevalence is higher in HCV infected people
75 THANK YOU

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Hepatitis ppt final

  • 1.
    1 HEPATITIS VIRUSES By Dr.D.W.Deshkar Assistant ProfessorDept. of Microbiology D.Y.Patil Medical College,Kolhapur
  • 2.
    2 What is ViralHepatitis ? • Viral hepatitis is a systemic disease with primary inflammation of the liver by any one of a heterogenous group of hepatotropic viruses
  • 3.
    3 HEPATITIS VIRUSES • HepatitisA (HAV) Picornaviridae (1973) • Hepatitis B (HBV) Hepadnaviridae (1970) • Hepatitis C (HCV) Flaviviridae (1988) • Hepatitis D (HDV) ? (1977) • Hepatitis E (HEV) (Caliciviridae) (1983), Hepeviridae • Hepatitis F – Not separate entity – Mutant of B Virus.
  • 4.
    4 Viral Hepatitis -Historical Perspectives “Infectious” AA Viral hepatitis NA:NBNA:NB E Enterically transmitted “Serum” B D C Parenterally transmitted F- Mutant Of B G
  • 5.
    5 Type of Hepatitis AB C D E Source of virus Feces Blood Blood derived Body fluids Blood Blood derived Body fluids Blood Blood derived Body fluids Feces Route of Transmission Feco-oral Percutaneous Permucosal Percutaneous Permucosal Percutaneous Permucosal Feco- oral Chronic Infection No Yes Yes Yes No Prevention Pre Post Exposure Immunization Pre Post Exposure Immunization Blood donor screening Blood donor screening Pre Post Exposure Immunization Ensure Safe Drinking water
  • 6.
  • 7.
    7 Hepatitis A Virus NakedRNA virus Related to enteroviruses, formerly known as Enterovirus 72, now put in its own family: heptoviridae One stable serotype only Difficult to grow in cell culture: primary marmoset cell culture and also in vivo in chimpanzees and marmosets 4 genotypes exist, but in practice most of them are group 1 RNA
  • 8.
    8 RESISTANCE ( HAV) •Resistant to inactivation by heat at 600 C for one hour, ether & acid at pH 3. • Inactivated by boiling for one minute, 1: 4,000 formaldehyde at 370 C for 72 hours & chlorine 1 ppm for 30 minutes. • Not affected by anionic detergents. • Survives prolonged storage at 40 C or below.
  • 9.
    9 Hepatitis A VirusTransmission • Close personal contact (e.g., household contact, sex contact, child day care centers) • Contaminated food, water (e.g., infected food handlers, raw shellfish) • Blood exposure (rare) (e.g., injecting drug use, transfusion)
  • 10.
    10 Prodromal or Preictericphase : (symptoms: fatigue, joint- and abdominal pain, malaise, vomiting, lack of appetite, hepatomegaly) Icteric phase: Icterus: jaundice (skin, sclera, mucous membranes, cause: elevated bilirubin level, bilirubinuria: dark urine, pale stool)
  • 11.
    11 PATHOGENESIS - HAV Causesubacute disease in children & young adults. HAV invade into human body by fecal-oral route, multiplies in the intestinal epithelium & reaches the liver by hematogenous spread. After one week, the HAV reach liver cells replicate within.Then enter intestine with bile and appear in feces. Incubation Period : 2 to 6 weeks.
  • 12.
    12 PATHOGENESIS – HAVcontd-- – After HAV replicating and discharging,liver cells damage begin – Animal experiment proved that immune complex may attend the pathogenesis of HAV – Complement level reduce the pathogenesis maybe following: – activated T cell secrete γ-INF that promote the representation of HLA on the liver cells,CTL may kill the target cell infected with HAV
  • 13.
    13 LAB.DIAGNOSIS 1. Demonstration ofVirus in feces: By: Immunoelectron microscopy 2. Virus Isolation: 3. Detection of Antibody :By ELISA 4. Biochemical tests: i) Alanine aminotransferase (ALT) ii) Bilirubin iii) Protein 5. Molecular Diagnosis : RT PCR of feces
  • 14.
    14 Fecal HAV Symptoms 0 1 23 4 5 6 1 2 2 4 Hepatitis A Infection IgG anti-HAV Titre ALT IgM anti-HAV Months after exposure Typical Serological Course
  • 15.
    15 • Many casesoccur in community-wide outbreaks – no risk factor identified for most cases – highest attack rates in 5-14 year olds – children serve as reservoir of infection • Persons at increased risk of infection – travelers – homosexual men – injecting drug users Hepatitis A Vaccination Strategies Epidemiologic Considerations
  • 16.
  • 17.
  • 18.
    18 1 、 Propertiesof HBV • a member of the hepadnavirus group • Circular partially double-stranded DNA viruses • Replication involves a reverse transcriptase. • endemic in the human population and hyperendemic in many parts of the world. • a number of variants • It has not yet been possible to propogate the virus in cell culture
  • 19.
  • 20.
    20 HBV : Structure •Virion also referred to as Dane particle (ds-tranded DNA) • 42nm enveloped virus • Core antigens located in the center (nucleocapsid) * Core antigen (HBcAg) * e antigen (HBeAg)- an indicator of transmissibility (minor component of the core- antigenically distinct from HBcAg) • 22nm spheres and filaments other forms- no DNA in these forms so they are not infectious (composed of surface antigen)- these forms outnumber the actual virions
  • 21.
    21 HBV Structure &Antigens Dane particleDane particle HBsAg = surface (coat) protein ( 4 phenotypes : adw, adr, ayw and ayr) HBcAg = inner core protein (a single serotype) HBeAg = secreted protein; function unknown
  • 22.
    22 decoy particles • HBsAg-containing particlesare released into the serum of infected people and outnumber the actual virions. • Spherical or filamentous • They are immunogenic and were processed into the first commercial vaccine against HBV.
  • 23.
  • 24.
    24 There are 4open reading frames derived from the same strand (the incomplete + strand) • S - the 3 polypeptides of the surface antigen (preS1, preS2 and S - produced from alternative translation start sites. • C - the core protein • P - the polymerase • X - a transactivator of viral transcription (and cellular genes?). HBx is conserved in all mammalian (but not avian) hepadnaviruses. Though not essential in transfected cells, it is required for infection in vivo. Open Reading Frames
  • 25.
    25 HBx activates theRas-Raf-MAPK cascade: Influence on cell proliferation?  HBx-mediated activation of the Ras-Raf-MAPK pathway has been linked to accelerated entry of cells into S phase  Unlike the magnitude of Ras activation by growth factors, HBx stimulation is modest but sustained  Downstream signaling: activate transcription factors (eg. AP-1, NF-ΚB and c-myc)  Activation of the Ras-Raf-MAPK signaling pathway is essential for HBx activation of AP-1 and NF-ΚB
  • 26.
    26 2 、 HBV:Replication • Reverse transcription: one of the mRNAs is replicated with a reverse transcriptase making the DNA that will eventually be the core of the progeny virion • RNA intermediate: HBV replicates through an RNA intermediate and produces and release antigenic decoy particles. • Integration: Some DNA integrates into host genome causing carrier state
  • 27.
  • 28.
    28  Parenteral -IV drug abusers, health workers are at increased risk.  Sexual - sex workers and homosexuals are particular at risk.  Perinatal (Vertical) – mother (HBeAg+) →infant. 33 、、 HBV:HBV: Modes of TransmissionModes of Transmission
  • 29.
    29 4 、 Epidemiology •350,000,000 carriers worldwide • 120,000,000 carriers in China - the carrier rate can exceed 10% -15 to 25% of chronically infected patients will die from chronic liver disease • 500,000 deaths/year in China • 982,297 liver disease in China 2005 • 50% of children born to mothers with chronic HBV in the US are Asian American
  • 30.
    30 High Moderate Low/Not Detectable blood semenurine serum vaginal fluid feces wound exudates saliva sweat tears Breast milk Concentration of Hepatitis B Virus in Various Body Fluids 伤口渗出液 唾液 精液 阴道分泌液
  • 31.
    31 High-risk groups forHBV infection • People from endemic regions • Babies of mothers with chronic HBV • Intravenous drug abusers • People with multiple sex partners • Hemophiliacs and other patients requiting blood and blood product treatments • Health care personnel who have contact with blood • Residents and staff members of institutions for the mentally retarded
  • 32.
    32 Symptoms HBe Ag anti-HBe Total anti- HBc IgM anti- HBc anti- HBsHBs Ag 0 4 8 12 16 20 24 28 32 36 52 100 Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Weeks after Exposure Titre
  • 33.
    33 5 、 Pathogenesis& Immunity • Virus enters hepatocytes via blood • Immune response (cytotoxic T cell) to viral antigens expressed on hepatocyte cell surface responsible for clinical syndrome • 5 % become chronic carriers (HBsAg> 6 months) • Higher rate of hepatocellular ca in chronic carriers, especially those who are “e” antigen positive • Hepatitis B surface antibody likely confers lifelong immunity (IgG anti-HBs) • Hepatitis B e Ab indicates low transmissibility
  • 34.
    34 6 、 ClinicalFeatures Incubation period: Average 60-90 days Range 45-180 days Insidious onset of symptoms. Tends to cause a more severe disease than Hepatitis A. Clinical illness (jaundice): <5 yrs, <10% ≥ 5 yrs, 30%-50% 1/3 adults-no symptoms Clinical Illness at presentation 10 - 15% Acute case-fatality rate: 0.5%-1% Chronic infection: < 5 yrs, 30%-90% ≥ 5 yrs, 2%-10% More likely in asymptomatic infections Premature mortality from chronic liver disease: 15%-25%
  • 35.
    35 Possible Outcomes ofHBV InfectionPossible Outcomes of HBV Infection Acute hepatitis B infection Chronic HBV infection 3-5% of adult- acquired infections 95% of infant- acquired infections Cirrhosis Chronic hepatitis 12-25% in 5 years Liver failureHepatocellular carcinoma Liver transplant 6-15% in 5 years 20-23% in 5 years DeathDeath
  • 36.
  • 37.
    37 Diagnosis • A batteryof serological tests are used for the diagnosis of acute and chronic hepatitis B infection. • HBsAg - used as a general marker of infection. • HBsAb - used to document recovery and/or immunity to HBV infection. • anti-HBc IgM - marker of acute infection. • anti-HBcIgG - past or chronic infection. • HBeAg - indicates active replication of virus and therefore infectiveness. • Anti-Hbe - virus no longer replicating. However, the patient can still be positive for HBsAg which is made by integrated HBV. • HBV-DNA - indicates active replication of virus, more accurate than HBeAg especially in cases of escape mutants. Used mainly for monitoring response to therapy.
  • 38.
    38 、 Current TreatmentOptions • Interferon alfa (Intron A) （干扰 素） Response rate is 30 to 40%. • Lamivudine (Epivir HBV) （拉米呋啶） (relapse ,drug resistance) • Adefovir dipivoxil (Hepsera) （阿德福韦酯）
  • 39.
    39 Treatment • Interferon -for HBeAg +ve carriers with chronic active hepatitis. Response rate is 30 to 40%. – alpha-interferon 2b (original) – alpha-interferon 2a (newer, claims to be more efficacious and efficient) • Lamivudine - a nucleoside analogue reverse transcriptase inhibitor. Well tolerated, most patients will respond favorably. However, tendency to relapse on cessation of treatment. Another problem is the rapid emergence of drug resistance. • Adefovir – less likely to develop resistance than Lamivudine and may be used to treat Lamivudine resistance HBV. However more expensive and toxic • Entecavir – most powerful antiviral known, similar to Adefovir • Successful response to treatment will result in the disappearance of HBsAg, HBV-DNA, and seroconversion to HBeAg.
  • 40.
    40 、 Prevention • Vaccination -highly effective recombinant vaccines • Hepatitis B Immunoglobulin (HBIG) -exposed within 48 hours of the incident/ neonates whose mothers are HBsAg and HBeAg positive. • Other measures -screening of blood donors, blood and body fluid precautions.
  • 41.
    41 Prevention • Vaccination -highly effective recombinant vaccines are now available. Vaccine can be given to those who are at increased risk of HBV infection such as health care workers. It is also given routinely to neonates as universal vaccination in many countries. • Hepatitis B Immunoglobulin - HBIG may be used to protect persons who are exposed to hepatitis B. It is particular efficacious within 48 hours of the incident. It may also be given to neonates who are at increased risk of contracting hepatitis B i.e. whose mothers are HBsAg and HBeAg positive. • Other measures - screening of blood donors, blood and body fluid precautions.
  • 42.
    42 Hepatitis B Vaccine •Infants: several options that depend on status of the mother – If mother HBsAg negative: birth, 1-2m,6-18m – If mother HBsAg positive: vaccine and Hep B immune globulin within 12 hours of birth, 1-2m, <6m • Adults * 0,1, 6 months • Vaccine recommended in – All those aged 0-18 – Those at high risk
  • 43.
    43 HEPATITIS C VIRION:spherical, icosahedral, NUCLEIC ACID: ss (+) RNA
  • 44.
  • 45.
    45 Hepatitis C Virus Genomeresembled that of a flavivirus positive stranded RNA genome of around 10,000 bases 1 single reading frame, structural genes at the 5' end, the non-structural genes at the 3' end. enveloped virus, virion thought to 30-60nm in diameter  morphological structure remains unknown HCV has been classified into a total of six genotypes (type 1 to 6) on the basis of phylogenetic analysis Genotype 1 and 4 has a poorer prognosis and response to interferon therapy In Hong Kong, genotype 1 accounts for around 67% of cases and genotype 6 around 25%.
  • 46.
    46 HCV replicates exclusivelyin the cytoplasm via an RNA intermediate Nucleus Viral entry & uncoating Translation & processing (+) (+) (-) (+) HCV RNA replicationVirus particle assembly Replicative intermediate
  • 47.
    47 Incubation period: Average6-7 wks Range 2-26 wks Clinical illness (jaundice): 30-40% (20- 30%) Chronic hepatitis: 70% Persistent infection: 85-100% Immunity: No protective antibody response identified Hepatitis C - Clinical Features
  • 48.
    48 Chronic Hepatitis CInfection • The spectrum of chronic hepatitis C infection is essentially the same as chronic hepatitis B infection. • All the manifestations of chronic hepatitis B infection may be seen, albeit with a lower frequency i.e. chronic persistent hepatitis, chronic active hepatitis, cirrhosis, and hepatocellular carcinoma.
  • 49.
    49 Symptoms anti- HCV ALT Normal 0 1 23 4 5 6 1 2 3 4 Hepatitis C Virus Infection Typical Serologic Course Titre Months Years Time after Exposure
  • 50.
    50  Transfusion ortransplant from infected donor  Injecting drug use  Hemodialysis (yrs on treatment)  Accidental injuries with needles/sharps  Sexual/household exposure to anti-HCV-positive contact  Multiple sex partners  Birth to HCV-infected mother Risk Factors Associated with Transmission of HCV
  • 51.
    51 Laboratory Diagnosis • HCVantibody - generally used to diagnose hepatitis C infection. Not useful in the acute phase as it takes at least 4 weeks after infection before antibody appears. • HCV-RNA - various techniques are available e.g. PCR and branched DNA. May be used to diagnose HCV infection in the acute phase. However, its main use is in monitoring the response to antiviral therapy. • HCV-antigen - an EIA for HCV antigen is available. It is used in the same capacity as HCV-RNA tests but is much easier to carry out.
  • 52.
    52 HCV RNA (PCRtesting) 􀂄 Virus load 􀂄 Lower detection limit can be 10-615 IU/ml 􀂄 NOT a predictor of disease severity: a high viral load does not mean the liver disease is more severe, and a low viral load does not mean the patient is ok and does not need therapy! 􀂄 Helps predict response rate to treatment (lower means a higher chance of cure with therapy) 􀂄 Used to monitor response during treatment
  • 53.
    53 Prognostic Tests • Genotyping– genotype 1 and 4 have a worse prognosis overall and respond poorly to interferon therapy. A number of commercial and in-house assays are available. – Genotypic methods – DNA sequencing, PCR- hybridization e.g. INNO-LIPA. – Serotyping – particularly useful when the patient does not have detectable RNA. • Viral Load – patients with high viral load are thought to have a poorer prognosis. Viral load is also used for monitoring response to IFN therapy. A number of commercial and in-house tests are available.
  • 54.
    54 Treatment • Interferon -may be considered for patients with chronic active hepatitis. The response rate is around 50% but 50% of responders will relapse upon withdrawal of treatment. • Ribavirin - there is less experience with ribavirin than interferon. However, recent studies suggest that a combination of interferon and ribavirin is more effective than interferon alone.
  • 55.
  • 56.
    56  Screening ofblood, organ, tissue donors  High-risk behavior modification  Blood and body fluid precautions Prevention of Hepatitis C
  • 57.
  • 58.
    58 Hepatitis Delta Virion FromMurray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia,, Figure 66-14
  • 59.
    59 HEPATITIS D VIRUS (HDV,DELTA AGENT) VIRION: spherical, 36-38 nm, HBV capsid, HDV nucleoprotein NUCLEIC ACID: (-) ss RNA, circular Satellite virus : replicates only in the presence of HBV
  • 60.
    60 Hepatitis D Virus •The delta agent is a defective virus which shows similarities with the viroids in plants. • The agent consists of a particle 35 nm in diameter consisting of the delta antigen surrounded by an outer coat of HBsAg. • The genome of the virus is very small and consists of a single-stranded RNA
  • 61.
    61 The HDV genome Figure88-4 Structure of the HDV RNA Genome. The single-stranded circular RNA genome is indicated by the heavy black continuous line. The genome has the ability to form an unbranched rod structure, in which approximately 70% of the bases are engaged in Watson-Crick pairs with counterparts from the opposite side of the circular RNA. In this unbranched rod structure, the region encoding HDAg (nt 1598-957) is on one side. The RNA editing site is at position 1012 in the antigenome. The region on the right-hand side contains the autocatalytic cleavage sites (ribozymes), one in the genome (nt 686) and the other in the antigenome (nt 900). The genome binds HDAg and is transcribed by a host DNA–dependent RNA polymerase. Fields Virology 4th edition, 2002, Chapter 88, Lippincott, Williams and Wilkins, 2002 Fig. 88-4
  • 62.
    62  Coinfection – severeacute disease. – low risk of chronic infection.  Superinfection – usually develop chronic HDV infection. – high risk of severe chronic liver disease. – may present as an acute hepatitis. Hepatitis D - Clinical Features
  • 63.
    63 Consequences of hepatitisB and delta virus infection Figure 66-15. Consequences of deltavirus infection. Deltavirus (d) requires the presence of hepatitis B virus (HBV) infection. Superinfection of a person already infected with HBV (carrier) causes more rapid, severe progression than co-infection (shorter arrow). From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia.
  • 64.
    64  Percutaneous exposures injectingdrug use  Permucosal exposures sex contact Hepatitis D Virus Modes of Transmission
  • 65.
    65 anti-HBs Symptoms ALT Elevated Total anti-HDV IgManti-HDV HDV RNA HBsAg HBV - HDV Coinfection Typical Serologic Course Time after Exposure Titre
  • 66.
    66 Jaundice Symptoms ALT Total anti-HDV IgM anti-HDV HDVRNA HBsAg HBV – HDV SuperinfectionTypical Serologic Course Time after Exposure Titre
  • 67.
    67  HBV-HDV Coinfection Preor post exposure prophylaxis to prevent HBV infection.  HBV-HDV Superinfection Education to reduce risk behaviors among persons with chronic HBV infection. Hepatitis D - Prevention
  • 68.
  • 69.
    69 Hepatitis E Virus •Calicivirus-like viruses • unenveloped RNA virus, 32-34nm in diameter • +ve stranded RNA genome, 7.6 kb in size. • very labile and sensitive • Can only be cultured recently
  • 70.
    70  Incubation period:Average 40 days Range 15-60 days  Case-fatality rate: Overall, 1%-3% Pregnant women, 15%-25%  Illness severity: Increased with age  Chronic sequelae: None identified Hepatitis E - Clinical Features
  • 71.
    71 Symptoms ALT IgG anti-HEV IgManti-HEV Virus in stool 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Hepatitis E Virus Infection Typical Serologic Course Titer Weeks after Exposure
  • 72.
    72  Most outbreaksassociated with faecally contaminated drinking water.  Several other large epidemics have occurred since in the Indian subcontinent and the USSR, China, Africa and Mexico.  In the United States and other nonendemic areas, where outbreaks of hepatitis E have not been documented to occur, a low prevalence of anti-HEV (<2%) has been found in healthy populations. The source of infection for these persons is unknown.  Minimal person-to-person transmission. Hepatitis E - Epidemiologic Features
  • 73.
    73  Avoid drinkingwater (and beverages with ice) of unknown purity, uncooked shellfish, and uncooked fruit/vegetables not peeled or prepared by traveler.  IG prepared from donors in Western countries does not prevent infection.  Unknown efficacy of IG prepared from donors in endemic areas.  Vaccine? Prevention and Control Measures for Travelers to HEV-Endemic Regions
  • 74.
    74 HEPATITIS G VÍRUS FLAVIRUS:similar morphology and genome ◊ in risk groups: acute, chronic and fulminant hepatitis ◊ transmission: blood (mother- newborn babies) ◊ prevalence is higher in HCV infected people
  • 75.