Viral Hepatitis and DNA Viruses (Microbiology)

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Questions and Answers

What is the primary mechanism by which Hepatitis B virus (HBV) causes liver damage?

CD8+ T-cell immune response (correct)

Accumulation of viral proteins in liver tissue

Direct viral lysis of hepatocytes

Inhibition of liver cell regeneration

Which of the following is NOT a typical symptom of Hepatitis B?

Dark urine

Pale stool

Yellowing of skin and eyes

Persistent cough (correct)

What characteristic of the Hepatitis D virus (HDV) is considered 'defective'?

Its transmission via blood and sexual contact

Its association with hepatocellular carcinoma

Its single-stranded RNA genome

Its inability to replicate without HBV (correct)

The envelope protein of Hepatitis D virus (HDV) is obtained from which source?

Hepatitis B virus (HBV) Signup and view all the answers

What is the main difference between a co-infection and a superinfection of HDV in relation to HBV?

Co-infection occurs simultaneously with HBV, while superinfection occurs later in a patient with chronic HBV. Signup and view all the answers

How is Hepatitis A virus (HAV) primarily transmitted?

By the fecal-oral route Signup and view all the answers

Which of the following best describes the nature of Hepatitis A virus (HAV) RNA?

Positive-sense single-stranded RNA Signup and view all the answers

What is a key characteristic of HAV that makes it resistant to disinfection?

Its acid-stability Signup and view all the answers

Which of the following is a unique characteristic of the Hepatitis B virus (HBV) DNA structure?

Nicked partially double-stranded circular DNA Signup and view all the answers

What is the primary function of the reverse transcriptase enzyme in the HBV life cycle?

To synthesize DNA from an RNA intermediate Signup and view all the answers

Which of the Hepatitis B antigens is the basis for the subunit vaccine?

HBsAg Signup and view all the answers

What role do the decoy particles produced by HBV play in infection?

Interfere with the host's immune system Signup and view all the answers

Which of the following types of cells are responsible for targeting and destroying HBV-infected hepatocytes?

CD8+ T-cells Signup and view all the answers

Which of the following statements is true regarding enveloped viruses, like HBV?

They are more susceptible to disinfection and do not persist long periods of time outside the body. Signup and view all the answers

Which of the listed methods is NOT a primary route of transmission for Hepatitis B virus?

Airborne droplets Signup and view all the answers

Which antigen is a breakdown product of the capsid antigen and can be detected during both acute and chronic HBV infections?

HBeAg Signup and view all the answers

What is a key difference in transmission route between Hepatitis E (HEV) strains 1 and 2, compared to HEV strain 3?

HEV-1 and HEV-2 are primarily transmitted through the fecal-oral route. Signup and view all the answers

Which hepatitis virus is known to have a 'quasi-enveloped' stage during its replication?

Hepatitis E virus (HEV) Signup and view all the answers

Which of these statements is true about Hepatitis C Virus (HCV)?

HCV can lead to chronic infection and liver damage, including hepatocellular carcinoma. Signup and view all the answers

What is the most common route of transmission for HCV, according to the text?

Exposure to infected blood, such as through IV drug use Signup and view all the answers

Which characteristic is specific to Hepatitis A virus (HAV) compared to Hepatitis C virus (HCV)?

HAV is resistant to disinfection Signup and view all the answers

What type of immune cell response is associated with liver damage in chronic HCV infections?

Cytotoxic T-cell (CD8 T cell) response Signup and view all the answers

Based on the information provided, what is a significant difference between the treatment of HCV and HAV infections?

Only HCV has antiviral treatments available, while HAV does not. Signup and view all the answers

Study Notes

Viral Hepatitis (Microbiology)

The presenter, Dr. Beatrice Saviola, Ph.D., has no conflicts of interest related to the presentation.
The lecture focuses on hepatitis viruses, specifically HAV, HBV, HCV, HDV, and HEV.
Students will be able to describe the viral structural characteristics, replication processes, pathogenic processes, and disease processes for each of the hepatitis viruses.
Different viruses are classified as DNA or RNA viruses, and in the case of HBV, it has a unique structural DNA.

Families of DNA Viruses

DNA viruses are categorized by symmetry of the capsid: naked or enveloped.
Examples of DNA viruses include: Parvovirus, Papovavirus, Adenovirus, Herpesvirus, Poxvirus, and Hepadnavirus.
Each virus family has specific DNA types (ssDNA, dsDNA).
The viruses have specific structures (i.e., virion, envelope, genome) and replicate within the cell, which is often in the nucleus or the cytoplasm.

HBV (Hepatitis B Virus)

HBV is in the Hepadnaviridae family.
HBV is an icosahedral enveloped virus, with a unique DNA structure, a partially double-stranded circular DNA.
Replication of HBV's DNA uses an intermediate RNA molecule
HBV can cause serum hepatitis or long-incubation hepatitis.
Transmission can occur through sexual contact, perinatal transmission, or close contact. In the U.S., blood is a significant mode of transmission, along with drug paraphernalia, and needle exposure or sticks.
A vaccine is available for HBV.
Several antigens are produced during the infection, including HBcAg (core antigen), HBeAg (breakdown product of core antigen), and HBsAg (surface antigen). HBsAg is crucial for vaccine development.

HDV (Hepatitis D Virus)

HDV is a defective virus that only replicates in the presence of HBV.
HDV is an RNA virus that has a non-segmented single-stranded RNA genome.
HDV is found in late 1970s in patients with HBV.

HAV (Hepatitis A Virus)

HAV is an RNA virus, and it is in the Picornaviridae family.
It is an acid-stable, resistant virus transmitted through the fecal-oral route.
HAV causes acute hepatitis.
HAV shares similar symptoms to other forms of hepatitis.

HCV (Hepatitis C Virus)

HCV is a flavivirus with a single-stranded RNA genome.
HCV can cause both acute and chronic hepatitis.
HCV is transmitted through blood, and can be spread through IV drug use, or other exposure to contaminated blood.
Symptoms can be acute or chronic, or no noticeable symptoms.
Some chronic infections cause hepatocellular carcinoma or cirrhosis.
There is no vaccine available.

HEV (Hepatitis E Virus)

HEV is in the Hepeviridae family, a (+ssRNA) virus that is similar to caliciviruses.
It's an unenveloped virus and spreads through the fecal-oral route.
HEV can sometimes be fatal in pregnant women.
HEV can cause acute hepatitis outbreaks.
HEV replication goes through a quasi-enveloped stage and contains an RNA polymerase to replicate the genome, which does not transport the enzyme into the host cell.

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Description

This quiz covers key concepts related to viral hepatitis and families of DNA viruses. Students will explore the structural characteristics and replication processes of hepatitis viruses such as HAV, HBV, HCV, HDV, and HEV, as well as DNA virus families classified by symmetry and structure. Gain insights into pathogenic processes and the unique nature of HBV as a DNA virus.