Viral Hepatits - Microbiology Flashcards
What is viral hepatitis ?
Liver inflammation caused by a cirus
What are the specific hepatitis virus labels?
A
B
C
D
E
All these viruses are not from the same family but belong to different families; however, liver is their common site of infection
Which other virsuses can cause hepatitis?
Epstein-Barr virus
Cytomegalovirus
But liver is not their main target
How many people are living with viral hepatitis globally?
354 million people globally
How many deaths did viral hepatitis cause globally in 2015?
1.34 million deaths
What was the main cause of death for hepatitis?
Chronic liver disease
What are the numbers of people affected with HBV and HCV?
HBV = 257 million
HCV = 71 million
Which hepatitis virus kinds are the ones responsible for 96% of mortality rates?
Hep B
Hep C
What are the symptoms of viral hepatitis?
Fatigue and flu-like symptoms
Dark urine and light-coloured stool
Fever
Jaundice
What is the clinical presentation of acute hepatitis like?
Occurs with minimal symptoms
What are the symptoms of chronic viral hepatitis like? What effect does that have on diagnosis?
Mild and nonspecific
Diagnosis of chronic hepatitis is delayed
What is hepatitis A?
A single-stranded RNA virus that belongs to the picornavirus family
Non-enveloped
How many capsid polypeptides does the HAV version contain?
4 virons, VP1 to VP4
That makes HAV the main atigen
What is the transmission route of HAV?
Fecal-oral
What is the incubation period of HAV?
Four week
Where is the replication site of HAV? Where is it present?
Replication is limited to the liver
Virus found in the liver, bile, stools, and blood
What happens when jaundice becomes apparent in HAV?
Fecal shedding, viremia, and infectivity diminish rapidly
What is the replication cycle of HAV like? (6)
- Viral attachment (receptor binding) to hepatocytes and entry
2.RNA uncoating - Translation and polyprotein processing
- RNA replication
- Viron assembly and packaging
- Maturation and release
What are the receptor that HAV binds to in order to enter the cell?
HAV cellular receptor, mucin-like cass 1 integral membrane glycoprotein
What is HBV?
A circular DNA virus enveloped (double shell virion), which belongs to the hapadnavirus family
What are the main HBV antigens?
HBsAg
HBcAg
HBeAg
What is the route of transmission of HBV?
Parenteral
Percutaneous
Sexual
What is the incubation period of HBV?
50 to 180 days
What is the percentage of chronic HBV cases?
5 to 10%
What does concentrated serum from patients with HBV show?
Tubular and spherical particles of HBV surface antigens
What is the HBV replication cycle like? (11)
- Viral attachment to hepatocytes
- Fusion into the plasma membrane
- Release of nucleocapsids
- Cytoplsamic release of viral circular DNA with its polymerase
- Synthesis of DNA strands
- Transcription of viral RNA needed for protein production
- Translation of pregenomic RNA to core protein and viral polymerase
- Self-assembly of pgRNA containing nucleocapsids
- Reverse transcription of pgRNA to circular DNA production
- cccDNA-containing nucleocapsids are either imported to nucleus for more DNA replication
OR - Enveloped and secreted as complete virus
What is HCV?
Single-stranded RNA virus enveloped, belongs to flavivirus family
What are the main antigens of HCV? (5)
HCV
C100-3
C33-C
C22-3
NSS
What is the transmission route of HCV?
Parenteral
What is the incubation period of HCV like?
40 to 120 days
What is the replication cycle of HCV like? (7)
- Viral attachment (receptor binding) to hepatocytes and entry
- Fusion into the plasma membrane and uncoating
- Translation and polyprotein processing
- RNA replication
- Viron assembly
- Maturation & transport
- Release
What is HDV?
A single-stranded RNA virus enveloped belongs to the Ribovria family
Which are the main antigens of HDV?
HDV and HBsAg
What is the transmission route of HDV?
Perenteral
What is a specific characteristic of HDV?
It exists only with HBV as a co-infection or super-infetion
What is HEV?
A single-stranded RNA virus non-enveloped, belongs to the Hepeviridae family
What is the main antigen of HEV?
HEV
What is the transmission route of HEV?
Fecal-oral route
What is the incubation period of HEV like?
40 days
Which hepatitis infection types are self-limiting ?
HAV
HEV
In which cases does the severity of HEV increase?
In pregnancy
Which hepatitis infection types cannot cause chronic infection?
HAV
HEV
What is the serological diagnosis of HAV?
Early fecal shedding diagnosis: IgM anti-HAV
Previous infection: IgG ant-HAV
What is the serological diagnosis of HBV?
Acute diagnosis: HBsAg, IgM anti-HBc
Chronic diagnosis: IgG anti-HBc, HBsAg
Markers of replication: HBeAg, HBV DNA
What is the serological diagnosis of HCV?
Acute diagnosis: anti-HCV (C33c, C22-3, NS5), HCV RNA
Chronic diagnosis: anti-HCV (C100-3, C33c, C22-3, NS5) HCV RNA
What is the serological diagnosis of HDV?
HBsAg, IgM-HDV
What is the serological diagnosis of HEV?
Acute fecal shedding: IgM-anti HEV
How are serological markers of viral hepatitis measured?
ELISA
What else is measured by ELISA?
Viral protein antigens and antibodies
How are molecular markers of viral hepatitis measured?
PCR
How is the viral load of viral hepatitis measured?
Quantitative RT - PCR
What are HCV infections like?
Mostly subclinical with mild or no symptoms
But account for about 75% of chronic viral hepatitis cases
Why is it difficult to clear HCV infections with antibody response?
HCV has rapid genetic mutations, enabling immune evasion
What are the serological tests like for a patient with Acute Hep B?
HBsAg: positive
IgM anti-HAV: negative
IgM anti-HBc: positive
Ant-HCV: negative
What are the serological tests like for a patient with Chronic Hep B?
HBsAg: positive
IgM anti-HAV: negative
IgM anti-HBc: negative
Ant-HCV: negative
What are the serological tests like for a patient with acute hep A superimposed on a chronic hep B patient?
HBsAg: positive
IgM anti-HAV: positive
IgM anti-HBc: negative
Ant-HCV: negative
What are the serological tests like for a patient with acute hep A and acute hep B?
HBsAg: positive
IgM anti-HAV: positive
IgM anti-HBc: positive
Ant-HCV: negative
What are the serological tests like for a patient with acute hep A?
HBsAg: negative
IgM anti-HAV: positive
IgM anti-HBc: negative
Ant-HCV: negative
What are the serological tests like for a patient with acute hep A and acute hep B (HBsAg below detection threshold)?
HBsAg: negative
IgM anti-HAV: positive
IgM anti-HBc: positive
Ant-HCV: negative
What are the serological tests like for a patient with acute hep B (HBsAg below detection threshold)?
HBsAg: negative
IgM anti-HAV: negative
IgM anti-HBc: positive
Ant-HCV: negative
What are the serological tests like for a patient with acute hep C?
HBsAg: negative
IgM anti-HAV: negative
IgM anti-HBc: negative
Ant-HCV: positive
What is the aim of the pharmacological therapy for viral hepatitis?
In chronic hep B and C therapy is recommended to reduce liver inflammation and fibrosis and to prevent progression to cirrhosis and its complications
What is the pharmacological therapy for viral hepatitis?
Interferons, antivirals, and corticosteroids
Which are the nucleoside analogies that have shown promising results in the treatment of hepatitis B?
Lamivudine
Adefocir
What is the pharmacological treatment for HCV?
Pegylated IFN
Antiviral ribavirin
What is the prophylactic immune therapy?
Specific immunoglobulins are derived from the plasma of donors with high titers of antibodies against hepatitis viruses
What is the main benefit of prophylactic immune therapy?
Specific immunoglobulins provide rapid post-exposure protection
What are HBIG and HAIG?
Specific immunoglobulin preparation against Hep B and specific immunoglobulin preparation against Hep A
Which viral hepatitis kinds are there vaccines available for?
HAV & HBV
What is the HAV vaccine like?
Inactivated virus that confers about 20 years of immunity against HAV, it is given in two doses, 6 months apart for longer protection
Who is recommended the HAV vaccine?
Travelers to endemic areas
Children over one year of age
People at high risk of infection
Who are the people considered at high risk of the HAV infcetion? (6)
Gay men
Drug users, both injection and non-injection
Family and caregivers before the arrival of international adoptees
People with chronic liver diseases
People who are treated with clotting factor concentrates
People who work with HAV-infected animals or in HAV labs
What is the suitable age for the administartion of the HAV vaccine?
Individuals aged one year and older
Who should receive the HBV vaccine? (9)
- All children at birth
- All children and teens < 19 yo who have not been vaccinated
- People who are sexually active with someone who is infected or share drug injection equipment
- People with chronic liver or kidney disease
- People with HIV
- People < 60 yo with diabetes
- People whose jobs expose them to human blood and other bodily fluids
- Residents and staff of facilities with people with developmental disabilities
- People who travel to parts of the world where HBV is common
What is the suitable age for the HBV vaccine?
Can be administered to individuals of all ages, from newborns to adults
Why is there no vaccine for HCV?
HCV has different genotypes
It mutates easily and changes
There is a lack of proper in-vitro cell culture model
Lack of proper animal model
What causes HCV to have different genotypes?
It is a quasivirus with various types of genotypes due to rapid mutations.
In which cases does HDV become chronic?
When with HBV
What can chronic viral hepatitis infections lead to?
Liver cirrhosis and liver cancer
What is liver cirrhosis?
A disease in which normal liver cells are replaced by scar tissue, which interferes with important functions in the liver
Which hepatitis type is the leading cause of cirrhosis and liver cancer?
HCV
What is the hepatocellular carcinoma?
Primary malignancy of the liver occurs predominantly in patients with underlying chronic liver disease and cirrhosis
What is the epidemiology of hepatocellular carcinoma?
3rd leading cause of cancer deaths worldwide, over 500000 affected