RNA Hepatitis viruses

What is another name for hepatitis D virus (HDV) infection?

Delta hepatitis

Which patients can HDV infect?

Only patients who have an acute or chronic HBV infection

What does HDV require for replication?

HBV

What type of virus is HDV?

A defective single-stranded RNA (ssRNA) virus

What does HDV require from HBV to form its envelope?

HBsAg

What protects the HDV genome?

Hepatitis D antigen

Approximately what percentage of people with HBV are affected by HDV?

About 5%

How many people worldwide are estimated to be infected with HDV?

Approximately 15 million

How is HDV transmitted?

The same routes as HBV

How can HDV be transmitted parenterally?

Through contaminated needles blood or body fluid exposure and blood transfusions

Can HDV be transmitted through sexual contact?

Yes

Can HDV be transmitted vertically?

Yes

What is HDV-HBV coinfection?

When HBV and HDV are acquired at the same time

What is the usual outcome of HDV-HBV coinfection?

It can cause self-limiting mild to severe infections

What percentage of patients with HDV-HBV coinfection develop chronic HDV infection?

Less than 5%

What is HDV superinfection?

When HDV is acquired during an existing chronic HBV infection

How does HDV superinfection affect chronic HBV infection?

It rapidly accelerates the disease in 70–90% of individuals

Which type of HDV infection more often causes fulminant hepatitis?

HDV superinfection

What percentage of patients with HDV superinfection develop chronic HDV infection?

More than 80%

How does HDV superinfection affect the development of cirrhosis?

Cirrhosis can occur up to a decade earlier than with HBV alone

How quickly can cirrhosis and liver failure occur in 70–80% of patients with HDV superinfection?

Within 5–10 years

How quickly can cirrhosis and liver failure occur in 15% of patients with HDV superinfection?

Within 1–2 years

Which antibody tests can help diagnose HDV infection?

Anti-HDV IgM and total anti-HDV (IgG and IgM)

What serologic findings indicate HBV-HDV coinfection?

Positive HBsAg positive anti-HBc IgM and positive anti-HDV

What molecular test can diagnose HDV infection?

HDV RNA PCR

How can hepatitis B vaccination prevent HDV infection?

By preventing HBV infection

Which interferon is used to treat HDV?

Interferon alpha

How does interferon alpha affect HDV infection?

It reduces viral load and slows disease progression and liver damage

What type of antivirals may be used to treat HDV?

Antivirals targeting HBV

What treatment may be used for severe HDV-related liver disease?

Liver transplantation

What type of virus is hepatitis A virus (HAV)?

A non-enveloped icosahedral single-stranded RNA virus

What family does HAV belong to?

Picornaviridae

What is the HAV nucleocapsid antigen called?

Hepatitis A antigen

How many serotypes does HAV have?

One

How is HAV transmitted?

Through the fecal-oral route

What activities can spread HAV through close contact?

Close person-to-person contact and sexual contact

How can contaminated food or water transmit HAV?

By ingestion

How can dirty hands contribute to HAV transmission?

They can transfer the virus to the mouth or food

Which groups have a higher risk of HAV infection?

International travelers MSM illicit drug users people with occupational exposure risk and homeless individuals

Where does HAV replicate?

In the cytoplasm of hepatocytes

What is the incubation period of HAV?

2–6 weeks

What percentage of children younger than 6 years with HAV are asymptomatic?

About 90%

How does HAV hepatitis typically begin?

Abruptly

What percentage of older children and adults with HAV develop jaundice?

More than 70%

How long does HAV infection usually take to resolve?

About 2–3 months

What percentage of HAV infections may last up to 6 months?

About 10–15%

What type of infection does HAV cause?

Acute infection without chronic infection

What information helps diagnose HAV?

Signs and symptoms patient history elevated liver enzymes anti-HAV antibody testing and HAV RNA PCR

Which antibody test can help diagnose acute HAV infection?

Anti-HAV IgM

What does a total anti-HAV test detect?

Both IgM and IgG antibodies

Which molecular test can detect HAV?

HAV RNA PCR in blood or stool

How can contaminated water be made safer to prevent HAV?

Boil it

How should food be prepared to help prevent HAV?

Cook it properly

What hygiene measure helps prevent HAV transmission?

Washing hands

When should immune globulin be given after HAV exposure?

Within 2 weeks of exposure

What type of vaccine is used to prevent HAV?

An inactivated HAV vaccine

Which vaccines protect against HAV alone?

HAVRIX and VAQTA

Which vaccine protects against both HAV and HBV?

Twinrix

What was HCV formerly called?

Non-A non-B (NANB) hepatitis

What family does HCV belong to?

Flaviviridae

Does HCV share homology with other hepatitis viruses?

No

What type of virus is HCV?

An enveloped single-stranded RNA virus

How many HCV genotypes are listed in the notes?

Seven

How many HCV subtypes are listed in the notes?

Sixty-seven

How are HCV subtypes labeled?

With a lowercase letter after the genotype number

Which HCV genotypes are most common in the United States?

Genotypes 1a 1b 2 and 3

How many people worldwide are estimated to have chronic HCV infection?

Approximately 58 million

How many adolescents and children worldwide are estimated to have chronic HCV infection?

Approximately 3.2 million

How many new HCV infections occur worldwide each year?

Approximately 1.5 million

How many deaths worldwide are estimated to result from hepatitis C each year?

Approximately 300

What major complications can result from chronic HCV infection?

Cirrhosis and hepatocellular carcinoma (HCC)

How many newly reported chronic hepatitis C cases were recorded in the United States in 2023?

101

How many hepatitis C-related deaths were recorded in the United States in 2023?

11

What can chronic HCV infection lead to that may require a liver transplant?

Liver failure and liver cancer

What is the most common route of HCV transmission in the United States?

Injection-drug use

What are other parenteral routes of HCV transmission?

Needlesticks contaminated razor or toothbrush sharing healthcare procedures such as hemodialysis and rarely blood transfusions

How can sexual contact transmit HCV?

Through sexual exposure

Can HCV be transmitted vertically?

Yes

What is the incubation period of HCV?

2–12 weeks

What percentage of acute HCV cases are asymptomatic?

About 70%

What percentage of HCV cases have mild symptoms?

About 20–30%

How common is fulminant hepatitis with HCV?

Extremely rare

What is responsible for much of the liver damage in HCV infection?

Cell-mediated immunity (CMI)

What percentage of individuals may clear HCV infection?

Up to 50%

What percentage of individuals may develop chronic HCV infection?

About 50–70%

Are antibodies formed against HCV considered protective?

No

Why are antibodies against HCV not considered protective?

HCV mutates rapidly because its RNA polymerase is error-prone

Can someone be infected with HCV again after a previous infection?

Yes

What percentage of people with chronic HCV develop cirrhosis within 10–20 years?

About 5–25%

What is the annual risk of developing HCC in people with HCV-related cirrhosis?

About 1–4%

What is the annual risk of developing liver failure in people with HCV-related cirrhosis?

About 3–6%

What is the risk of death in the following year for people with HCV-related cirrhosis according to the notes?

About 15–20%

Who should receive HCV screening in the United States?

All adults older than 18 once per lifetime

When should pregnant women receive HCV screening?

During every pregnancy

Who else should receive routine periodic HCV screening?

People with risk factors

What initial antibody test is used to screen for HCV?

Anti-HCV antibody testing

When does anti-HCV seroconversion usually occur after exposure?

On average 8–12 weeks after exposure

When can anti-HCV seroconversion be delayed?

In immunocompromised or immunosuppressed individuals

What must a positive anti-HCV screening test be confirmed with?

HCV RNA testing

What does NAT stand for in HCV testing?

Nucleic acid testing