hepatitis (miscro) Flashcards by abdullah wael ,

Compare the genomic structure and envelope status of the five primary hepatitis viruses (HAV, HBV, HCV, HDV, HEV).

-Enveloped:
HBV: Partially dsDNA.
HCV: +ssRNA.
HDV: ssRNA.
-Non-enveloped (Naked):
HAV: +ssRNA.
HEV: +ssRNA.

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Name three viruses that can infect the liver as a secondary target.

1-Yellow fever virus.
2-Epstein-Barr virus (EBV).
3-Cytomegalovirus (CMV).

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What does the persistence of HBsAg for more than 6 months indicate?

A chronic Hepatitis B infection.

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What does the presence of HBeAg suggest?

Active viral replication and high infectivity.

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What is the significance of elevated ALT levels in a hepatitis patient?

It reflects ongoing liver inflammation and damage (hepatocyte injury) due to viral activity.

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List three major long-term complications of chronic HBV infection.

1-Liver cirrhosis.
2-Hepatocellular carcinoma (HCC).
3-Liver failure.

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What are the two main classes of drugs used for treating chronic active HBV?

1-Interferon-alpha.
2-Nucleos(t)ide analogues (e.g., lamivudine, tenofovir).

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Describe the “Dane particle”. What are its main components, and which antigens are associated with each component?

The Dane particle is the intact, infectious HBV virion.
-Envelope (Outer shell): Contains HBsAg (Hepatitis B surface antigen).
-Nucleocapsid (Core): Contains the viral DNA and two additional antigens:
=>HBcAg* (core antigen): Confined to liver cells.
=>HBeAg (e-antigen): Secreted from infected cells into the blood.

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Besides the infectious Dane particle, what are the two other non-infectious forms of HBsAg found in the blood, and why are they non-infectious?

-Forms:
1-Spherical particles (22 nm).
2-Tubular/filamentous particles (22 x 200 nm).

-Reason for being non-infectious: They are composed only of the HBsAg envelope and do not contain any viral DNA.

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To which virus family does HBV belong?

Hepadnaviridae family.

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What is the common name for the disease caused by HBV?

Serum hepatitis.

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List the three main modes of HBV transmission.

-Blood & percutaneous transmission.
-Sexual contact.
-Perinatal transmission (mother to fetus).

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Name four groups of people who are at high risk for HBV infection.

-Sexual partners of hepatitis patients.
-Infants of infected mothers.
-Parenteral drug addicts.
-Haemodialysis patients.
-Healthcare workers.
-Individuals undergoing tattooing.

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Is the liver damage in HBV infection caused directly by the virus itself? Explain the mechanism.

No, the damage is not caused directly by the virus. It is immune-mediated.
The host’s cytotoxic T cells (Tc cells) recognize and attack the HBV-infected hepatocytes, leading to liver inflammation and damage.

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A patient with acute HBV presents with a skin rash and joint pain before the onset of jaundice. What is the immunological basis for these “extra-hepatic manifestations”?

These manifestations are caused by the deposition of immune complexes (antigen-antibody complexes, likely involving HBsAg) in the small blood vessels of the skin (causing rash/vasculitis), joints (causing polyarthralgia), and glomeruli (causing glomerulonephritis).

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Compare the typical clinical presentation and risk of chronicity in a perinatally infected infant versus an infected adult.

-Perinatally Infected Infant:
=>Presentation: Usually asymptomatic with normal liver enzymes.
=>Chronicity Risk: Very high (approx. 90%).
-Infected Adult:
=>Presentation: Often symptomatic (jaundice, malaise, etc.) in 33-50% of cases.
=>Chronicity Risk: Much lower (5-10%).

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What is “fulminant hepatitis,” and what are three potential causes for this severe outcome?

-Definition: A rare but severe complication of acute hepatitis leading to acute hepatic failure.

-Potential Causes:
1-Massive immune-mediated lysis of infected hepatocytes.
2-Infection with a more virulent HBV strain.
3-Co-infection with another hepatitis virus (like HCV or HDV).

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What is the incubation period for HBV?

6 weeks to 6 months.

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List three constitutional symptoms that may precede jaundice in an HBV infection.

1-Malaise.
2-Anorexia.
3-Nausea / Vomiting.

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What percentage of adults with acute HBV infection develop chronic infection?

5-10%.

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Compare a “chronic active hepatitis” patient to a “chronic carrier” based on liver enzymes and viral load.

-Chronic Active Hepatitis:
=>Liver enzymes: Elevated.
=>Viral load: High.
-Chronic Carrier:
=>Liver enzymes: Normal.
=>Viral load: Low or undetectable.

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A patient’s blood test shows they are negative for both HBsAg and HBsAb, but positive for HBcIgM. What is the name of this specific phase of infection, and why is HBcIgM the key diagnostic marker here?

-Phase: This is the “window phase” of an acute HBV infection.
-Reason: It occurs after HBsAg has disappeared from the blood but before the protective anti-HBs (HBsAb) has appeared. During this gap, HBcIgM is the only positive marker

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Which hepatitis B marker is the first to appear in the blood and indicates active infection (acute or chronic)?

HBsAg

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Which antibody indicates immunity to HBV?

Anti-HBs (HBsAb).

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Which antibody is the best indicator of a recent or acute HBV infection?

IgM anti-HBc (HBcIgM).

Which marker is associated with high infectivity and active viral replication?

HBeAg

A person has a positive HBsAb test, but is negative for all other markers (HBsAg, HBcAb). What is the most likely explanation?

*Immunity following HBV vaccination*. The vaccine contains only HBsAg, so the body only produces anti-HBs and has no exposure to the core antigen (so HBcAb is negative).

What does the persistence of HBsAg for more than 6 months indicate?

**Indication**: A **chronic Hepatitis B infection**. This is the defining marker for chronicity.

What does the presence of HBeAg and a high HBV DNA level suggest?

**Active viral replication and high infectivity**. The patient is actively producing the virus and can easily transmit it.

What are the potential long-term complications of chronic HBV infection?

=>Complications: -Liver cirrhosis -Hepatocellular carcinoma (HCC) -Liver failure

What is the name of the intact, infectious HBV virion?

=>**Name**: The **Dane particle**. =>**Note**: The smaller spherical and tubular particles are non-infectious as they **lack viral DNA**.

What causes the extra-hepatic manifestations (e.g., rash, vasculitis) in HBV infection?

The deposition of immune complexes

In which age group is the risk of developing chronic HBV infection the highest (approx. 90%)?

Perinatally infected infants,

A patient's serology is: HBsAg (-), HBcAb (+), HBsAb (+). What is the interpretation?

-**Interpretation: Immunity following natural HBV infection.** **Reasoning**: HBsAb (+) indicates immunity, and HBcAb (+) indicates past exposure to the core antigen from a real infection.

A patient's serology is: HBsAg (-), HBcAb (-), HBsAb (+). What is the interpretation?

-**Interpretation: Immunity following HBV vaccination.** -**Reasoning:** HBsAb (+) indicates immunity, but HBcAb (-) shows no exposure to the core antigen, which is only present in a natural infection.

What does post-exposure prophylaxis for an unvaccinated person exposed to HBV consist of?

-**Prophylaxis**: Administration of both **Hepatitis B immunoglobulin (HBIG)** for immediate passive immunity and the **HBV vaccine** series for long-term active immunity.

Hepatitis D virus (HDV) is a defective virus that requires co-infection with which other virus to replicate?

Hepatitis B Virus (HBV)

What is the most common HCV genotype in Egypt and the Middle East?

Genotype 4

What is the main mode of transmission for Hepatitis C Virus (HCV)?

Parenterally by contaminated blood (e.g., IV drug use, needle-prick injury).

What is the approximate rate of chronicity for HCV infection?

High, around **80%** of cases progress to chronic hepatitis

What is the role of RT-PCR in diagnosing HCV?

**Role**: To detect viral RNA, which is useful for diagnosing **early acute cases** (before antibodies appear) and confirming **active viral replication** in chronic cases.

What is the mechanism of action for Sofosbuvir (Sovaldi), a modern HCV treatment?

It is a nucleoside analogue inhibitor that directly inhibits the viral RNA polymerase, thus stopping viral replication.

What is the standard HBV vaccination schedule for adults?

Schedule: Three intramuscular (I.M.) doses given at 0, 1, and 6 months.

What is the purpose of genotyping HCV before starting treatment?

The virus genotype is the strongest predictor of the response to therapy.

How is Sofosbuvir (Sovaldi) used in combination therapy for different HCV genotypes?

Mechanism: Sofosbuvir is a nucleoside analogue inhibitor. Combination Therapy: For Genotypes 2 & 3: It is used with Ribavirin. For Genotypes 1 & 4: It is used with Interferon

What is the family and genomic structure of Hepatitis A Virus (HAV)?

Family: Picornaviridae Genome: Non-enveloped, positive-sense single-stranded RNA (+ssRNA).

What is the family and genomic structure of Hepatitis B Virus (HBV)?

Family: Hepadnaviridae Genome: Enveloped, partially double-stranded DNA (partially dsDNA).

What is the family and genomic structure of Hepatitis C Virus (HCV)?

=>**Family**: Flaviviridae =>**Genome**: Enveloped, positive-sense single-stranded RNA (+ssRNA).

What is the family and genomic structure of Hepatitis E Virus (HEV)?

=>**Family**: Caliciviridae Genome: **Non-enveloped**, positive-sense single-stranded RNA (+ssRNA).

What is the defining characteristic of Hepatitis D Virus (HDV)?

=>**Characteristic**: It is a defective virus (ssRNA) that requires the presence of Hepatitis B virus (HBV) to replicate and cause infection.

What is the primary mode of transmission for both HAV and HEV?

Feco-oral route

What is the typical clinical outcome of an HAV infection?

It is a **self-limited** disease that does **not** lead to chronic hepatitis. It provides long-lasting immunity.

What is the vaccination schedule for the inactivated HAV vaccine (Havrix)?

Two intramuscular (I.M.) doses given at **0 and 6 months**.

The "Twinrix" vaccine provides combined protection against which two hepatitis viruses?

Hepatitis A Virus (HAV) and Hepatitis B Virus (HBV)

What is the family and vector of the Yellow Fever virus?

**Family**: Flaviviridae **Vector**: Mosquitoes (e.g., Aedes aegypti in urban cycles).

What are the three characteristic clinical findings ("triad") of a severe Yellow Fever infection?

High fever, **jaundice**, and **albuminuria** (protein in the urine), often accompanied by bleeding.

What type of vaccine is the Yellow Fever (17D) vaccine?

-A live attenuated virus vaccine, -grown in chick embryo. -It provides protection for 10 years.

What is the incubation period for HAV?

Incubation Period: 2-6 weeks.

What is the incubation period for Yellow Fever?

3-6 days

Which two viruses discussed are non-enveloped RNA viruses?

Hepatitis A Virus (HAV) and Hepatitis E Virus (HEV)

Which of the discussed viruses is a DNA virus?

**Hepatitis B Virus** (HBV), which has a partially **double-stranded DNA genome.**

What is the reservoir for Hepatitis A Virus?

It mostly affects children and young adults

What is the purpose of passive immunization with HAV-Ig?

For post-exposure prophylaxis ,especially in immunodeficient persons

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

Approximately 6 weeks

Which mosquito species transmits Yellow Fever in the jungle cycle in South America?

**Mosquito**: Haemagogus species. **Note**: In Africa, the vector is Aedes africanus.

How is the Yellow Fever (17D) vaccine administered?

As a single injection subcutaneously

hepatitis (miscro) Flashcards

(67 cards)