Hepatitis Virus Transmission and Immune Response Quiz

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Questions and Answers

What is the primary mode of transmission for Hepatitis E Virus (HEV)?

Sexual contact

Fecally contaminated drinking water (correct)

Airborne particles

Blood transfusions

What is the typical incubation period for Hepatitis E Virus (HEV)?

1 to 2 weeks

12 to 16 weeks

9 to 12 weeks

3 to 8 weeks (correct)

Which of the following populations is at higher risk for fulminant hepatitis associated with HEV?

Healthy adults

Elderly men

Pregnant women (correct)

Children under 5 years old

Which serological marker indicates an acute HEV infection?

IgM anti-HEV Signup and view all the answers

Which diagnostic method is NOT used for testing HEV infections?

Liver biopsy Signup and view all the answers

What is the estimated number of people globally infected with Hepatitis B Virus (HBV)?

2 billion Signup and view all the answers

Which serious condition is commonly associated with HBV?

Chronic infections Signup and view all the answers

What is the primary function of virus-specific antibodies in the humoral immune response?

To neutralize free virus particles and prevent infection spread. Signup and view all the answers

Which antibodies are particularly important for neutralizing viruses in mucosal surfaces?

Secretory IgA Signup and view all the answers

How do IgG antibodies contribute to the immune response against viruses?

By promoting antibody-dependent cell-mediated cytotoxicity and opsonization. Signup and view all the answers

What is the role of CD8 cytotoxic T lymphocytes (CTL) in the immune response?

To attack and eliminate infected host cells. Signup and view all the answers

What is the main component of the hepatitis B vaccine that was licensed in 1982?

HBsAg purified from blood Signup and view all the answers

Which of the following is NOT a recommended measure to prevent HBV infection?

Use of antiviral treatment without guidelines Signup and view all the answers

What must occur for cytotoxic T cells to recognize and eliminate virus-infected cells?

The T-cell receptor must bind to a viral antigen-MHC class I complex. Signup and view all the answers

What is the function of perforin released by activated cytotoxic T cells?

To create pores in the membranes of virus-infected cells. Signup and view all the answers

Who is encouraged to receive the hepatitis B vaccine in Saudi Arabia?

Infants, children, and high-risk individuals Signup and view all the answers

What role do granzymes play in the immune response?

They induce apoptosis in infected host cells. Signup and view all the answers

What is the average incubation period for hepatitis B virus infection?

45 to 90 days Signup and view all the answers

What structural component of the HBV is found in its outer envelope?

Hepatitis B surface antigen (HBsAg) Signup and view all the answers

What is the primary method for diagnosing acute hepatitis A in symptomatic patients?

Presence of IgM antibodies to HAV Signup and view all the answers

What is NOT a mechanism by which antibodies act against viruses?

Induction of cell death in infected cells. Signup and view all the answers

What characterizes the presence of total HAV antibodies in relation to IgM anti-HAV?

Positive total anti-HAV and negative IgM indicates immunity Signup and view all the answers

Which genotypes of HBV have been identified?

Eight genotypes, designated A through H Signup and view all the answers

During which periods is HAV antigen shed in feces of infected individuals?

Incubation period and early acute stage Signup and view all the answers

What is the potential outcome for approximately 1% of adults infected with HBV?

Fulminant liver disease with high fatality rate Signup and view all the answers

What is a significant outcome of the hepatitis A vaccination introduced in the mid-1990s?

A significant decrease in the number of HAV infections Signup and view all the answers

What does HBIG stand for and what is its purpose?

Hepatitis B Immune Globulin - for temporary protection Signup and view all the answers

Which group is now routinely recommended to receive the hepatitis A vaccine?

Children aged 12 to 23 months Signup and view all the answers

What type of virus is Hepatitis E Virus (HEV)?

Non-enveloped, single-stranded RNA virus Signup and view all the answers

In which scenarios is the hepatitis A vaccine recommended for individuals?

For children and travelers to endemic areas Signup and view all the answers

What is the most common method for detecting HAV RNA in patients?

Reverse transcriptase polymerase chain reaction (RT-PCR) Signup and view all the answers

What is the consequence of virus-infected B cells becoming polyclonally activated?

They produce a variety of antibodies. Signup and view all the answers

Which symptom is NOT typically associated with infectious mononucleosis?

Skin rash Signup and view all the answers

Which antibodies are primarily involved in the acute phase of infectious mononucleosis?

IgM heterophile antibodies Signup and view all the answers

How long do heterophile antibodies typically last after the onset of symptoms in most patients?

They usually disappear by 3 months. Signup and view all the answers

What is the significance of IgM antibody to the viral capsid antigen (VCA)?

It is the primary marker for acute infectious mononucleosis. Signup and view all the answers

Which statement is true regarding the persistence of EBV in the body?

It can persist indefinitely in a small percentage of B cells. Signup and view all the answers

Which of the following antibodies persists for life following EBV infection?

IgG anti-VCA Signup and view all the answers

What type of activation do heterophile antibodies undergo when produced during infectious mononucleosis?

Polyclonal activation Signup and view all the answers

What is considered the 'gold standard' for EBV serology methods?

Indirect immunofluorescence assays (IFA) Signup and view all the answers

Which method is considered more reliable than serology for detecting EBV in immunocompromised patients?

Molecular tests Signup and view all the answers

What is the most common cause of congenital infections?

Cytomegalovirus (CMV) Signup and view all the answers

How is Cytomegalovirus (CMV) primarily spread?

Prolonged contact with infectious body secretions Signup and view all the answers

Which laboratory method is NOT typically used for diagnosing CMV infection?

Indirect immunofluorescence assays Signup and view all the answers

What aspect makes ELISA tests preferable for many laboratories despite the higher specificity of IFA?

Faster processing time Signup and view all the answers

What type of patients might not demonstrate a good humoral response to EBV?

Immunocompromised patients Signup and view all the answers

What type of cells does CMV persist in a latent state?

Monocytes, dendritic cells, and myeloid progenitor cells Signup and view all the answers

Study Notes

Viral Structure and Characteristics

Viruses are submicroscopic particles measured in nanometers.
Basic viral structure includes a core of DNA or RNA packaged within a protein coat (capsid).
Some viruses have an outer envelope of glycolipids and proteins derived from the host cell membrane.
Viruses are obligate intracellular pathogens, relying on host cells for replication and survival.

Viral Infection Mechanisms

Viruses infect host cells by attaching to specific receptors on the cell surface.
They penetrate the host cell membrane.
Viral genetic material (DNA or RNA) is released, directing host cell machinery to produce more viral components.
New viruses assemble within the cell, either by lysis or budding off the cell's surface, to infect new cells.
Free virions (complete virus particles) spread the infection.

Immune System Response to Viral Infection

Innate immune response provides the initial defense against viral pathogens.
Type I interferons and Natural Killer (NK) cells are crucial nonspecific defenses against viruses.
Virus-infected cells stimulated to produce IFN-α and IFN-β after recognizing viral RNA or DNA by Toll-like receptors (TLRs).
Interferons inhibit viral replication and enhance the activity of NK cells which further induce cell death to prevent viral spread.
Phagocytes, such as macrophages, play a role in pathogen clearance through various PRRs including TLRs and NLRs.

Adaptive Immune Response

Virus-specific antibodies produced by B cells and plasma cells neutralize free virus particles, preventing infection.
Antibodies bind to viral components that bind to a host cell receptor thus blocking viral entry into the cell.
Antibodies can activate complement and promote phagocytosis.
Cytotoxic T cells (CTLs) target virus-infected host cells.
Upon activation, CD8+ T cells attack the virus-infected cells through cytotoxicity to prevent virus replication.
CTLs bind to virus-infected cells via MHC class I complex and deliver cytotoxic proteins (perforin and granzymes) directly to the infected cell which induces apoptosis.

Viral Strategies to Evade the Immune System

Frequent genetic mutations generating new viral antigens enables viruses to escape immune detection.
Viruses can disable immune components such as interferons, complement proteins, and lysosomal enzymes preventing efficient immune responses.
Viruses may suppress the immune system. Infections may reduce MHC molecule expression, making the virus-infected cells harder for the immune system to identify and eliminate them.
Some viruses can directly alter the function of immune cells, such as B cells or T cells after directly infecting them thus altering normal immune responses.
Some viruses can establish latency, integrating their nucleic acid into the host cell's genome, hindering immune responses and enabling persistence.

Viral Hepatitis

Hepatitis is a general term representing liver inflammation often caused by viruses or other agents.
Several viruses can cause hepatitis, including HAV, HBV, HCV, HDV, and HEV.
Various factors including the transmission routes, clinical manifestations, diagnostic approaches and treatments.

Hepatitis A (HAV)

HAV is a non-enveloped, single-stranded RNA virus.
HAV is transmitted through the fecal-oral route.
The infection is typically self-limiting with symptoms usually resolving within 2 months.
Diagnosis involves detecting HAV antigens, IgM antibodies to HAV during acute phase, and total HAV antibodies for confirmation.

Hepatitis E (HEV)

HEV is a non-enveloped, single-stranded RNA virus.
HEV is transmitted through the fecal-oral route, mainly related to consumption of fecally contaminated water in regions with poor sanitation, and it causes acute, self-limiting hepatitis.
Diagnosis typically uses serological testing (IgM and IgG antibodies to HEV) and molecular tests (RT-PCR) detect HEV RNA.

Hepatitis B (HBV)

HBV is a DNA virus.
HBV is transmitted primarily via the parenteral route (blood, other body fluids like semen, vaginal secretions, and saliva).
It can cause both acute and chronic hepatitis, with chronic infections increasing the risk of liver complications.
Diagnosis primarily relies on detecting HBsAg, HBeAg, and specific antibodies in the blood.

Hepatitis D (HDV)

HDV is a defective RNA virus that relies on HBV for replication and expression and can only occur in the presence of HBV.
Transmission routes similar to HBV.
Diagnosis focuses on detecting HDV RNA through molecular tests (PCR) and specific antibodies via serological assays.

Hepatitis C (HCV)

HCV is an enveloped virus.
HCV is transmitted mainly through contact with infected blood, including unsafe injections and intravenous drug use.
Chronic HCV infection can lead to cirrhosis and liver cancer.
Diagnosis commonly involves serological testing for HCV antibodies (IgG) and molecular methods for HCV RNA.

Herpes Viruses

Herpesviruses are a family of DNA viruses that cause latent infections.
Diagnosis utilizes different virus-specific antigens through serology and/or molecular tests.
Multiple Herpesviruses exist and have different manifestation, transmission routes and impact.

Epstein-Barr Virus (EBV)

EBV is a member of the herpesvirus family.
EBV usually occurs through physical contact with saliva from an infected person.
It causes infectious mononucleosis and is associated with some cancers.
Diagnosis often involves serological tests to detect IgM and IgG antibodies to the virus-specific antigens.

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Description

Test your knowledge on Hepatitis E and B viruses with this comprehensive quiz. It covers topics such as transmission, incubation periods, populations at risk, and the immune response. Challenge yourself to understand the intricacies of these viral infections and their prevention measures.