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Specific Bloodborne Pathogens

Hepatitis A Virus (HAV)

Hepatitis A is a vaccine-preventable liver infection caused by the hepatitis A virus (HAV). HAV is found in the stool and blood of people who are infected. Hepatitis A is very contagious. It is spread when someone unknowingly ingests the virus — even in microscopic amounts — through close personal contact with an infected person or through eating contaminated food or drink.

Symptoms of hepatitis A can last up to 2 months and include fatigue, nausea, stomach pain, and jaundice. Most people with hepatitis A do not have long-lasting illness. The best way to prevent hepatitis A is to get vaccinated.

Complications of Hepatitis include cirrhosis (scarring) of the liver, liver cancer, and liver failure. There is no known cure for the hepatitis A virus, but most people make a full recovery. However, a very small proportion of people infected with hepatitis A could die from fulminant hepatitis.

Hepatitis A is transmitted through the fecal-oral route. This can happen through:

  • Close person-to-person contact with an infected person
  • Sexual contact with an infected person
  • Ingestion of contaminated food or water

Hepatitis A incidence increased 850% from 2014 to 2018. The increase in 2018 was primarily due to unprecedented person-to-person outbreaks reported in more than 30 states among people who use drugs and people experiencing homelessness.

1. The increase in hepatitis A is primarily due to _____.

a. compromised immune systems in the elderly
b. person-to-person contact among drug users
c. decreased liver function due to alcohol
d. septicemia after prolonged exposure to the virus

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Hepatitis B
Hepatitis B Virus Structure.
(Click to enlarge)
Chart of HBV Incidence
Incidence of acute HBV.

Hepatitis B Virus (HBV)

The hepatitis B virus (HBV) is one of the primary causes of Hepatitis, an infection which causes inflammation of the liver. Complications of Hepatitis include cirrhosis (scarring) of the liver, liver cancer, and liver failure. There is no known cure for the hepatitis B virus. In the United States, approximately 15 to 25 percent of people infected with HBV will die because of the illness.

Hepatitis B can be either acute or chronic.

  • Acute hepatitis B virus infection is a short-term illness that occurs within the first 6 months after someone is exposed to the hepatitis B virus. Acute infection can, but does not always, lead to chronic infection.
  • Chronic hepatitis B virus infection is a long-term illness that occurs when the Hepatitis B virus remains in a person's body. Chronic hepatitis B is a serious disease that can result in long-term health problems, and even death.

In 2018, a total of 3,332 cases of acute hepatitis B were reported to CDC. CDC estimates the actual number of acute hepatitis B cases was almost 21,600 in 2018. Rates of acute hepatitis B remained low in children and adolescents, likely due to childhood vaccinations. However, over half of acute hepatitis B cases reported to CDC in 2018 were among persons aged 30–49 years.

2. The hepatitis B virus causes an inflammation and possibly cirrhosis of the _____.

a. lungs
b. heart
c. liver
d. kidneys

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Hepatitis B Virus (HBV) (continued...)

The appearance of jaundice in the eyes.
(Click to enlarge)

Symptoms of HBV

Signs and symptoms of hepatitis B range from mild to severe. They usually appear about one to four months after you've been infected, although you could see them as early as two weeks post-infection. Symptoms may include:

  • Abdominal pain
  • Dark urine
  • Fever
  • Joint pain
  • Loss of appetite
  • Nausea and vomiting
  • Weakness and fatigue
  • Yellowing of your skin and the whites of your eyes (jaundice)

The classic symptom of HBV is jaundice. It is a yellowing of the skin or eyes and occurs in the more serious phase of Hepatitis B virus. Hepatitis B can damage the liver, resulting in decreased liver function. As the liver's ability to filter waste from the blood decreases, the concentration of waste in the blood increases.

Jaundice, a symptom of hepatitis B, often first appears in the eyes.

Only about 30 to 50 percent of individuals infected with Hepatitis B virus show symptoms. It is important to understand even without symptoms, HBV-infected individuals are still infectious to others.

Click here to view the CDC fact sheet for Hepatitis B. (PDF)

3. What is the classic symptom of hepatitis B?

a. Loss of appetite
b. Fatigue
c. Jaundice
d. Nausea and vomiting

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Hepatitis B Virus (HBV) (continued...)


An exposure that might place a worker at risk for HBV, HCV, or HIV infection is defined as:

  1. A percutaneous injury (e.g., a needlestick or cut with a sharp object); or
  2. Contact of mucous membrane or nonintact skin (e.g., exposed skin that is chapped, abraded, or afflicted with dermatitis) with blood, tissue, or other body fluids that are potentially infectious.
  3. Indirect exposure from contaminated objects is a risk because hepatitis B virus can remain infectious on environmental surfaces for up to a week (7 days) in the form of dried blood.

This means you must always treat blood, wet or dry, as infectious!


A vaccination to prevent Hepatitis B virus infection is available. The Hepatitis B vaccine series is a sequence of three shots, typically given one month apart, that stimulate a person's natural immune system to protect against the virus. After the vaccine is given, the body makes antibodies to protect a person against the virus. Antibodies are specialized proteins found in the blood that produce an immune response to a virus invading the body. These antibodies are stored in the body to guard against future infections. They will fight off an infection if a person is exposed to the Hepatitis B virus in the future.


Michelle is a custodian in a public elementary school. At the end of each school day, she cleans and vacuums the building, including the school's health room. While cleaning the health room she notices some dried blood on the floor.

Should Michelle be concerned about exposure to hepatitis B virus?


Any blood, wet or dry, has the potential to carry infectious hepatitis B virus. As a result, Michelle must take precautions to prevent potential exposure to bloodborne pathogens, including Hepatitis B virus.

4. After the hepatitis B vaccine is given, what does the body do to protect a person against the virus?

a. It will prevent exposure to the virus
b. It creates immunity for a short time
c. It creates a barrier to new infections
d. It makes antibodies against the virus

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Hepatitis C Virus (HCV)

Chart of HBV Incidence
Incidence of acute HCV.
(Click to enlarge)

The hepatitis C virus (HCV) is also a significant cause of severe liver damage and death.

Rates of acute hepatitis C increased in 2018 to 3,621 new cases and an estimated 50,300 acute infections. Most infections are among those aged 20-39 years, consistent with age groups most impacted by the nation’s opioid crisis.

About 3.5 million Americans are currently living with hepatitis C and roughly half are unaware of their infection. Approximately 1 to 5% of people infected with hepatitis C virus die as a result of the long-term damage caused to the liver and body.

Approximately 70%-80% of people with acute hepatitis C do not have any symptoms. Some people, however, can have mild to severe symptoms soon after being infected, including:

  • fever
  • fatigue
  • loss of appetite
  • nausea
  • vomiting
  • abdominal pain
  • dark urine
  • grey-colored bowel movements
  • joint pain
  • jaundice (yellow color in the skin or eyes)

Click here to view the CDC fact sheet for Hepatitis C. (PDF)

5. Approximately how many people infected with the hepatitis C virus die as a result of the long-term damage caused to the liver and body?

a. Over 50%
b. 25%
c. 5% or less
d. About 20%

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Hepatitis C Virus (HCV) (continued...)

Hepatitis C virus-infected individuals are infectious to other people, whether they show symptoms or not. Many people infected with the hepatitis C virus do not develop symptoms. Interestingly, Hepatitis C virus is strictly a human disease. It is not known to cause disease in any animals.

If symptoms do occur, the average incubation period is 45 days after exposure, but this can range from 14 to 180 days.

Blood testing for hepatitis C virus was not available until 1992. As a result, blood donation agencies did not screen for hepatitis C virus. Many hepatitis C virus infections occurred as a result of receiving blood products from infected individuals. Today, testing for hepatitis C is common place and should occur after any exposure to potential bloodborne pathogens.

There is no vaccine for Hepatitis C.


According to the CDC, approximately 15% to 25% of people infected with acute Hepatitis C will naturally be able to clear the infection from their body without treatment.

There are several medications available to treat chronic hepatitis C, including newer, more effective drugs with fewer side effects.

Around the World

According to the World Health Organization (WHO), 1.75 million people are infected with the hepatitis C virus each year. Approximately 71 million people are chronically infected and at risk of developing liver cirrhosis and/or liver cancer. About 400,000 people worldwide die from hepatitis C-related liver diseases each year.


Any blood spills - including dried blood, which can still be infectious - should be cleaned using a 10% dilution (1 part household bleach to 9 parts water). Gloves should always be worn when cleaning up blood spills.


Manuel is a nurse working nights in the local hospital. During a shift in the emergency department he is stuck with a used needle that punctures his skin and draws blood.

Is Manuel at risk for contracting Hepatitis C?


After a needlestick or sharps exposure to Hepatitis C-positive blood, the risk of infection is approximately 1.8%. Manuel should immediately report the potential exposure and follow his employer's exposure control plan to ensure he receives proper medical treatment and testing.

6. Infectious blood spills should be cleaned using a _____ dilution (1 part household bleach to 9 parts water).

a. 5%
b. 10%
c. 15%
d. 20%

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Hepatitis D Virus (HDV)

Hepatitis D is a liver disease caused by the hepatitis D virus (HDV). HDV is known as a "satellite virus," because it can only infect people who are also infected by the hepatitis B virus (HBV). HDV infection can be acute or lead to chronic, long-term illness. The infection can be acquired either simultaneously with HBV as a coinfection or as a superinfection in people who are already chronically infected with HBV.

HDV infection is uncommon in the United States, where most cases occur among people who migrate or travel to the United States from countries with high HDV infection rates. Because hepatitis D is not a nationally notifiable condition, the actual number of hepatitis D cases in the United States is unknown.

HDV is mainly transmitted through activities that involve percutaneous (i.e., puncture through the skin) and to a lesser extent through mucosal contact with infectious blood or body fluids (e.g., semen and saliva).

HDV causes infection and clinical illness only in HBV-infected people. The signs and symptoms of acute HDV infection are indistinguishable from those of other types of acute viral hepatitis infections.

Hepatitis E Virus (HEV)

Hepatitis E is a liver infection caused by the hepatitis E virus (HEV). HEV is found in the stool of an infected person. It is spread when someone unknowingly ingests the virus – even in microscopic amounts.

In developing countries, people most often get hepatitis E from drinking water contaminated by feces from people who are infected with the virus. In the United States and other developed countries where hepatitis E is not common, people have gotten sick with hepatitis E after eating raw or undercooked pork, venison, wild boar meat, or shellfish.

Symptoms of hepatitis E can include fatigue, poor appetite, stomach pain, nausea, and jaundice. However, many people with hepatitis E, especially young children, have no symptoms. Except for the rare occurrence of chronic hepatitis E in people with compromised immune systems, most people recover fully from the disease without any complications. No vaccine for hepatitis E is currently available in the United States.

7. HDV is known as a "satellite virus," because it can only infect people who are _____.

a. suspected of having been infected with the hepatitis C virus (HCV)
b. infected with any hepatitis virus
c. suffering from underlying conditions
d. also infected by the hepatitis B virus (HBV)

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Human Immunodeficiency Virus (HIV)

HIV attacking immune cell.
Human Immunodeficiency Virus (green) attacking a healthy immune system cell.
(Click to enlarge)

HIV disease continues to be a serious health issue for parts of the world. Worldwide, there were about 1.7 million new cases of HIV in 2018. About 37.9 million people were living with HIV around the world in 2018, and 24.5 million of them were receiving medicines to treat HIV, called antiretroviral therapy (ART).

The Human immunodeficiency virus attacks and suppresses the immune system, reducing a person's ability to fight infection. The virus specifically targets the cells crucial for fighting infection from pathogens. This allows diseases and infections to progress without resistance.

Within a few weeks of being infected with HIV, some people develop flu-like symptoms that last for a week or two, but others have no symptoms at all. People living with HIV may appear and feel healthy for several years. However, even if they feel healthy, HIV is still affecting their bodies. Untreated early HIV infection is also associated with many diseases including cardiovascular disease, kidney disease, liver disease, and cancer.


Stacy is a police officer employed by the city of Denver, Colorado. She is regularly required to respond to emergency medical situations, often arriving before the local ambulance company. As a result, Stacy is frequently exposed to human blood.

Is Stacy likely to contract HIV from exposure to infected blood?


If Stacy follows universal precautions she is not likely to contract HIV. Universal precautions involve the use of protective barriers such as gloves, gowns, aprons, masks, or protective eyewear.

8. Which virus specifically targets the cells crucial for fighting infection from pathogens?

a. Human Immunodeficiency Virus (HIV)
b. Hepatitis C Virus (HCV)
c. Hepatitis B Virus (HBV)
d. Hepatitis A Virus (HAV)

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Human Immunodeficiency Virus (HIV) (continued...)

HIV Virus Structure
HIV virus attachment to a Target T Cell.

It can take many years before an HIV-infected person displays symptoms of the disease.

Symptoms include:

  • enlarged lymph nodes
  • fatigue
  • frequent fevers
  • persistent or frequent yeast infections of the mouth or vagina
  • persistent or frequent skin rashes
  • short-term memory loss
  • weight loss
  • enlarged liver and spleen

According to the opinion of the CDC, there is no known cure for HIV. Treatment for HIV is called antiretroviral therapy or ART. If people with HIV take ART as prescribed, their viral load (amount of HIV in their blood) can become undetectable. If it stays undetectable, they can live long, healthy lives. Today, someone diagnosed with HIV and treated before the disease is far advanced can live nearly as long as someone who does not have HIV.

HIV cannot reproduce outside the human body. It is not spread by:

  • air or water
  • insects, including mosquitoes: studies conducted by CDC researchers and others have shown no evidence of HIV transmission from insects
  • saliva, tears, or sweat: there is no documented case of HIV being transmitted by spitting
  • casual contact like shaking hands or sharing dishes
  • closed-mouth or "social" kissing

All reported cases suggesting new or potentially unknown routes of transmission are thoroughly investigated by state and local health departments with assistance, guidance, and laboratory support from the CDC.

Disease Comparison

Of the three major bloodborne pathogens, hepatitis B virus is the most contagious. Approximately 33% of individuals exposed to hepatitis B virus will become infected. Of those individuals exposed to hepatitis C virus, only about 2% will become infected.

HIV is much less contagious than either form of hepatitis. About 0.33%, or 1 in 300, people exposed to HIV will become infected with the virus. Despite these statistics, every exposure has the potential to transmit bloodborne pathogens and must be considered significant.

9. Which of the following is the latest opinion of the CDC regarding a cure for HIV?

a. There is no known cure
b. Those successfully treated can live long lives
c. HIV readily reproduces outside the body
d. You can catch HIV if bitten by insects

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Methicillin-resistant Staphylococcus Aureus (MRSA)

Methicillin-resistant Staphylococcus Aureus is a common multi-drug-resistant bacterium that causes staph infections (MRSA) in different parts of the body. It is carried by about 2‰ of the population in the U.S. with nearly 19,000 infections resulting in sepsis causing death.

Staph infections are common among the general population, and since the 1970s, there has been a dramatic increase in infections caused by MRSA in hospitals and clinics, nursing homes, laboratories, and housekeeping, and is becoming more common in locker rooms and laundry facilities. The MRSA bacterium has become resistant to many antibiotics and is now considered a "superbug."

HIV Virus Structure
MRSA is drug-resistant.
(Click to enlarge)

MRSA can cause severe problems including:

  • bloodstream infections
  • pneumonia
  • skin/injury site infections
  • sepsis
  • death

Preventing the Spread of MRSA

  • Cover your wounds with clean, dry bandages until healed.
    • Follow your healthcare provider's instructions about proper care of the wound. Pus from infected wounds can contain MRSA.
    • Do not pick at or pop the sore.
    • Throw away bandages and tape with the regular trash.
  • Clean your hands often. Wash hands often with soap and water or use an alcohol-based hand rub, especially:
    • after changing a bandage
    • after touching an infected wound
    • after touching dirty clothes
  • Do not share personal items such as towels, washcloths, razors, and clothing, including uniforms.
  • Wash laundry before use by others and clean your hands after touching dirty clothes.

10. Which of the following bloodborne pathogens has become drug-resistant and is considered a "superbug?"

a. Hepatitis B Virus (HBV)
b. Hepatitis C Virus (HCV)
c. Human Immunodeficiency Virus (HIV)
d. Methicillin-resistant Staphylococcus Aureus (MRSA)

Check your Work

Read the material in each section to find the correct answer to each quiz question. After answering all the questions, click on the "Check Quiz Answers" button to grade your quiz and see your score. You will receive a message if you forgot to answer one of the questions. After clicking the button, the questions you missed will be listed below. You can correct any missed questions and check your answers again.


Video - What is Viral Hepatitis A, B, C, D, and E (46:16) Optional

If you have time, watch this excellent optional video by Sarvesh Shukla on hepatitis Viral A, B, C, D, E (causes, symptoms, diagnosis, treatment).

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