Presentation on theme: "An Overview Terry Kotrla, MS, MT(ASCP)BB Unit 4 Part 4 Hepatitis A-E Viruses."— Presentation transcript:
An Overview Terry Kotrla, MS, MT(ASCP)BB Unit 4 Part 4 Hepatitis A-E Viruses
Background Viral hepatitis caused by infection by any of at least five distinct viruses. Hepatitis A, B and C most common ones identified in US. Produce acute illness characterized by: Nausea Malaise Abdominal pain Dark urine Jaundice HBV and HCV can become chronic, associated with increased risk of chronic liver disease and hepatocellular carcinoma.
A “Infectious” “Serum” Viral hepatitis Enterically transmitted Parenterally transmitted F, G, TTV ? other E NANB BD C Viral Hepatitis - Historical Perspectives
Source of virus fecesblood/ blood-derived body fluids blood/ blood-derived body fluids blood/ blood-derived body fluids feces Route of transmission fecal-oral percutaneous permucosal percutaneous permucosal percutaneous permucosal fecal-oral Chronic infection noyes no Preventionpre/post- exposure immunization pre/post- exposure immunization blood donor screening; risk behavior modification pre/post- exposure immunization; risk behavior modification ensure safe drinking water Summary of Viral Hepatitis ABCDE
RNA virus Humans only natural host Can be stable in environment for months. Children younger than 6 years of age may have asymptomatic infection (70%). Older children and adults usually symptomatic, jaundice occurring in 70%.
Transmitted by 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) Hepatitis A Virus Transmission
Incubation period:Average 28 days Range 15-50 days Jaundice by age group: 14 yrs, 70%-80% Complications:Fulminant hepatitis Cholestatic hepatitis Relapsing hepatitis Chronic sequelae:None Hepatitis A - Clinical Features
Fecal HAV Symptoms 0123 4561212 2424 Hepatitis A Infection Total anti-HAV TiterALT IgM anti-HAV Months after exposure Typical Serological Course
Endemicity Disease Rate Peak Age of InfectionTransmission Patterns HighLow to High Early childhood Person to person; outbreaks uncommon ModerateHighLate childhood/ young adults Person to person; food and waterborne outbreaks Low Young adultsPerson to person; food and waterborne outbreaks Very low AdultsTravelers; outbreaks uncommon Global Patterns of Hepatitis A Virus Transmission
Laboratory Diagnosis Acute infection is diagnosed by the detection of IgM anti- HAV in serum by EIA. Generally detectable 5-10 days before onset of symtpoms. May persist for up to 6 months. Past infection is determined by the detection of IgG anti- HAV by EIA. Appears during convalescence. Present in serum forever, confers lifelong immunity. PCR helpful during outbreaks to determine common source.
Many cases occur in community-wide outbreaks No risk factor identified for most cases Highest attack rates in 5-14 year olds Asymptomatic children serve as source of infection Persons at increased risk of infection Travelers Homosexual men Injecting drug users Hepatitis A Vaccination Strategies Epidemiologic Considerations
Pre-exposure Travelers to intermediate and high HAV-endemic regions Post-exposure (within 14 days) Routine Household and other intimate contacts Selected situations Institutions (e.g., day care centers) Common source exposure (e.g., food prepared by infected food handler) Hepatitis A Prevention - Immune Globulin
Incubation period:Average 60-90 days Range 45-180 days Clinical illness (jaundice):<5 yrs, <10% 5 yrs, 30%-50% Acute case-fatality rate:0.5%-1% Chronic infection:<5 yrs, 30%-90% 5 yrs, 2%-10% Premature mortality from chronic liver disease:15%-25% Hepatitis B - Clinical Features
Hepatitis B Diseases DNA virus May cause: Chronic Persistent Hepatitis – asymptomatic Chronic Active Hepatitis – symptomatic exacerbations of disease Cirrhosis of liver Hepatocellular Carcinoma Liver failure Death
Symptoms HBeAg anti-HBe Total anti-HBc IgM anti-HBc anti-HBs HBsAg 0481216 20 242832 36 52100 Acute HBV Infection with Recovery Typical Serologic Course Weeks after Exposure Titer
IgM anti-HBc Total anti-HBc HBsAg Acute (6 months) HBeAg Chronic (Years) anti-HBe 048 12 16202428 32 36 52 Years Weeks after Exposure Titer Progression to Chronic HBV Infection - Serology
Symptomatic Infection Chronic Infection Age at Infection Chronic Infection (%) Symptomatic Infection (%) Birth 1-6 months7-12 months 1-4 years Older Children and Adults 0 20 40 60 80 100 80 60 40 20 0 Outcome of Hepatitis B Virus Infection by Age at Infection Chronic Infection (%)
High (>8%): 45% of global population lifetime risk of infection >60% early childhood infections common Intermediate (2%-7%): 43% of global population lifetime risk of infection 20%-60% infections occur in all age groups Low (<2%): 12% of global population lifetime risk of infection <20% most infections occur in adult risk groups Global Patterns of Chronic HBV Infection
HighModerate Low/Not Detectable bloodsemenurine serumvaginal fluidfeces wound exudatessalivasweat tears breastmilk Concentration of Hepatitis B Virus in Various Body Fluids
Sexual - sex workers and homosexuals are particular at risk. Parenteral - IVDA, Health Workers are at increased risk. Perinatal - Mothers who are HBeAg positive are much more likely to transmit to their offspring than those who are not. Perinatal transmission is the main means of transmission in high prevalence populations. Hepatitis B Virus Modes of Transmission
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.
Treatment Interferon - for HBeAg positive carriers with chronic active hepatitis. Response rate is 30 to 40%. 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. Successful response to treatment will result in the disappearance of HBsAg, HBV-DNA, and seroconversion to HBeAg.
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.
hypervariable region capsidenvelop e protein protease/helica se RNA- dependent RNA polymerase c22 5’ cor e E1E2NS 2 NS 3 33c NS 4 c-100 NS 5 3’ Hepatitis C Virus
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
Chronic Hepatitis C Infection RNA virus 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.
Symptoms anti- HCV ALT Normal 012345 61234 Hepatitis C Virus Infection Typical Serologic Course Titer Months Years Time after Exposure
Transfusion or transplant from infected donor Injecting drug use Hemodialysis (years 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
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.
Viral Load Done by PCR Negative defined as less than 100 copies/mL 200,000 to 1,000,000 low 1,000,000 to 5,000,000 medium 5,000,000 to 25,000,000 high above 25,000,000 very high
Treatment for HCV Treatment based on HCV viral load. Interferon May be considered for patients with chronic active hepatitis. Response rate is around 50% but 50% of responders will relapse upon withdrawal of treatment. Ribavirin Less experience than with interferon. Recent studies suggest combination of interferon and ribavirin.
Prevention of Hepatitis C Screening of blood, organ and tissue donors. High-risk behavior modification. Blood and body fluid precautions.
Hepatitis D Clinical Features RNA virus Coinfection with Hepatitis B required Severe, acute disease Low risk of chronic infection Super infection Usually develop chronic HDV infection High risk of severe chronic liver disease May present as an acute hepatitis.
Heptaitis D Virus Modes Transmission Percutaneous exposure Injecting (IV) drug use. Permucosal exposure Sexual contact
anti-HBs Symptoms ALT Elevated Total anti-HDV IgM anti-HDV HDV RNA HBsAg HBV - HDV Coinfection Serology Time after Exposure Titer
Jaundice Symptoms ALT Total anti-HDV IgM anti-HDV HDV RNA HBsAg HBV - HDV Superinfection Typical Serologic Course Time after Exposure Titer
Hepatitis D Prevention Because HDV requires HBV for replication pre- or postexposure prophylaxis to prevent HBV infection. No product exists to prevent HDV superinfection in persone with chronic HBV infection. Educate to reduce risk behaviors among persons with chronic HBV infecion.
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
Symptoms ALT IgG anti-HEV IgM anti-HEV Virus in stool 012345678910101 1212 1313 Typical Serologic Course of HEV Infection Titer Weeks after Exposure
Hepatitis E Features RNA virus Uncommon in US, associated with travel. Spread by fecal-oral route. Most outbreaks associated with fecal contamination of drinking water. Large epidemics still occur
Prevention and Control Measures Travelers to HEV Endemic regions should use caution. Avoid drinking water and beverages with ice, uncooked shellfish and uncooked fruit or vegetables which are 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?
Diagnosis and Treatment of HEV Diagnosis Suspect based on travel history to endemic area and negative serologic markers for HAV, HBV, and HCV Testing for presence of antibody to HEV. Detection of HEV RNA. Treatment No specific treatment available, most people recover completely. Fatality rate <4% Pregnant women much more serious, 10-30% fatal, especially in 3 rd trimester.