Blood-borne illness and disease

Definition

Blood-borne illnesses and diseases are caused by pathogens that are transmitted through contact with contaminated blood. The most common blood-borne diseases are human immunodeficiency virus HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). HBV and HCV are both diseases of the liver. HIV is a virus that destroys immune cells, leaving the body unable to fight infection. HIV can eventually progress to acquired immune deficiency syndrome (AIDS).

Exposure

Blood-borne illnesses and diseases are spread by direct contact with contaminated blood or other body fluids, such as semen. They also can be transmitted during childbirth from a woman to her fetus. Common methods of transmission include the following: having sex with a person who is infected with a blood-borne illness or disease; needle sharing during drug use; needle pricks or other puncture wounds made by sharp objects that are contaminated with infected blood or other body fluids; being splashed in the face with infected blood or body fluids (contact with eyes, nose, or mouth); sharing personal items, such as razors or toothbrushes, that have come in contact with the blood or body fluids of an infected person; getting contaminated blood or body fluid in an open sore or wound; contact with open sores on someone who has a blood-borne illness or disease; and blood transfusions.

Blood-borne illnesses and diseases cannot be transmitted through casual contact, such as hand-holding, kissing, hugging, shaking hands, or eating food prepared by someone who is infected. Also, these diseases are not transmitted through saliva unless the saliva is contaminated with blood.

There are some occupations that may put a person at risk of contacting potentially contaminated blood or body fluids. These include healthcare workers, sanitation workers, public safety personnel (such as police officers, emergency medical technicians, and firefighters), housekeepers, teachers, blood bank staff, dentists and dental hygienists, funeral home staff, and first aid workers.

Others who may be at increased risk of exposure to blood-borne illness and disease include men with same-sex partners, individuals with multiple sex partners, people whose sex partners are infected, persons on hemodialysis, persons who have another sexually transmitted disease, men who are not circumcised, and individuals who use intravenous drugs.

Once someone has been exposed to a blood-borne pathogen, several variables may determine whether that person actually contracts a blood-borne illness or disease. These variables include the type of pathogen to which the person has been exposed, how the person was exposed to the pathogen, how much blood or body fluid the person came in contact with during the exposure, and the amount of virus in the infected person’s blood at the time of the exposure.

Prevention

Some blood-borne illnesses and diseases (such as HBV) can be prevented through vaccination. The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) recommend that all infants be given the hepatitis B vaccine as part of their routine immunization schedule. WHO also recommends that all children under the age of eighteen who were not vaccinated at birth be given the vaccine. It is also recommended that people in the following groups, who are considered at increased risk for exposure, should be vaccinated: people with multiple sex partners, men with same-sex partners, partners of people who are infected with HBV, individuals who use injection drugs, people who frequently require blood or blood products, organ donation recipients, healthcare workers and other workers who are at increased risk of occupational exposure, and people traveling to countries with high rates of HBV.

There are also some high-risk settings in which many people may be at risk for HBV. The CDC recommends that all adults who receive care in the following high-risk settings be given the HBV vaccine: testing and treatment facilities for sexually transmitted diseases, drug abuse rehabilitation facilities, correctional facilities, hemodialysis facilities, and facilities for the developmentally disabled.

There is no vaccination for the prevention of HIV or HCV. The best way to prevent HIV, HCV, and other blood-borne illnesses and diseases for which there is no vaccination is to take the following precautions to avoid exposure to blood or body fluids of people who are or who may be infected: Wash hands before and after eating, after using the toilet, and after contact with another person’s blood or body fluids; wear disposable gloves when touching anything that may have come in contact with blood or body fluids, including wound dressings; avoid sharing personal items, such as razors or toothbrushes; avoid sharing needles for injection-drug use; and use latex condoms during sex.

Healthcare workers should use universal precautions when there is a possibility of being exposed to blood or body fluid. The CDC defines “universal precautions” as a set of precautions designed to prevent the transmission of HIV, HBV, and other blood-borne pathogens when providing first aid or healthcare. Universal precautions should be used when there is a potential for contact with blood, semen, vaginal secretions, or other types of body fluid, including cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids.

Universal precautions include the use of personal protective equipment (PPE), such as gloves, gowns, masks, and protective eyewear. Gloves should be worn when there is a potential for the hands to come in contact with blood or body fluids. Gloves should be changed between each patient, and hands should be washed after gloves are removed.

PPE should be worn during any procedure in which there is a potential that the healthcare worker may be splashed by blood or body fluids. The purpose of PPE is to keep the blood or body fluid from coming in contact with the worker’s clothes, skin, eyes, mouth, or nose.

All healthcare workers should take precautions to prevent needle sticks by using safe practices, such as not recapping needles and disposing of needles in appropriate puncture-resistant containers. Also, a number of safety devices on the market are designed to prevent needle sticks. These devices should be used, when available.

Persons exposed to blood or to a potentially infectious body fluid can help prevent blood-borne illness or disease by taking the following measures: Areas stuck by a needle or other sharp object should immediately be washed with soap and water. Eyes splashed with blood or body fluid should be rinsed with clean water or saline. A nose or mouth splashed with blood or body fluids should be flushed with water.

A blood test may be needed following an exposure to see if the person involved has contracted a blood-borne disease or illness. Postexposure treatment may also be recommended, so immediate medical attention is critical. For example, a person who has been exposed to blood or body fluid and has not had the HBV vaccine should, according to the CDC, get the vaccine as a precautionary measure, even if the person whose blood they came into contact with has not been diagnosed with HBV. For persons exposed to HIV, the US Public Health Service recommends a four-week course of antiretroviral drugs. There is no known postexposure treatment to prevent HCV infection.

Symptoms

Between 50 and 70 percent of people who are infected with HBV have no symptoms. Others may have any of the following symptoms: Fatigue, nausea and vomiting, loss of appetite, itching of the skin, pain in the upper right abdomen, dark urine, light-colored stools, or a yellowing of the skin and the whites of the eyes (jaundice).

Chronic HBV may eventually progress to cirrhosis of the liver, a scarring of the liver that prevents it from functioning properly. People who develop cirrhosis may have some or all of the symptoms associated with HBV, plus the following: bruising of the skin; swelling of the ankles and legs (edema); abdominal swelling; vomiting of blood; black, tarry stools; dizziness or fainting; confusion; and memory loss.

The severity of symptoms will depend on the progression of the disease. Cirrhosis can also increase a person’s risk of developing liver cancer.

Between 75 and 85 percent of people with HCV do not have any symptoms, or only have mild symptoms, until the disease has progressed to a late stage. Symptoms of HCV are similar to those of HBV and may also include fatigue, nausea and vomiting, diarrhea, loss of appetite, pain in the upper right abdomen, dark urine, light-colored stools, and yellowing of the skin and the whites of the eyes (jaundice). Some people may live with HCV for many years without developing any major liver damage. Others will develop cirrhosis, liver cancer, or liver failure.

Symptoms of HIV vary depending on the stage of the illness. When HIV is first contracted, there may be no symptoms at all, or there may be a brief period of flu-like symptoms, such as headache, fever, sore throat, and swollen lymph glands. These symptoms may also be accompanied by a skin rash. As immune cells begin to deteriorate over a period of years, the infected person may experience diarrhea, weight loss, fever, swollen lymph nodes, shortness of breath, and cough. When the disease progresses to AIDS, symptoms may include night sweats, fever, chills, diarrhea, mouth sores, cough, shortness of breath, fatigue, weight loss, skin rash, headache, and blurred vision.

Treatment

There is no cure for HBV, HCV, or HIV infection. Acute HBV usually resolves on its own, although medications are sometimes given to relieve symptoms. Chronic HBV is generally treated with antiviral medications that are intended to slow or stop the progression of the disease. HCV is also treated with antiviral medications and liver transplant, in extreme cases.

Liver transplant is often the only treatment option for HBV or HCV, when damage to the liver becomes severe enough to be life-threatening. If it is determined that the liver has sustained severe damage, a liver transplant may be required. Some people, however, may not be eligible for a liver transplant. These people include those who are actively abusing alcohol or drugs, those with cancer whose cancer has spread outside the liver, those who have other conditions that may make the transplant unlikely to be successful (such as advanced heart or lung disease or severe infection), those with major liver failure with associated brain injury, and those who are HIV-positive.

A liver transplant will not cure HBV or HCV, so treatment with antivirals will still be necessary following transplant surgery. Liver transplant patients will likely sustain damage to the new liver over time.

HIV is usually treated with a combination of anti-HIV drugs that are intended to control the virus. There are five different classes of drugs, and each class works in a different way to slow the spread of the virus. HIV drug classes include the following:

• Non-nucleoside reverse transcriptase inhibitors (NNRTIs). NNRTIs keep the HIV virus from multiplying by interfering with a protein called reverse transcriptase.
• Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). Like NNRTIs, NRTIs keep HIV from multiplying by interfering with reverse transcriptase. The difference between the two drug classes is their method of interference.
• Protease inhibitors (PIs).PIs keep HIV from multiplying by interfering with a protein called protease.
• Entry inhibitors, including fusion inhibitors. Entry inhibitors and fusion inhibitors keep HIV from entering human immune cells.
• Integrase inhibitors (IHs).IHs keep HIV from inserting its genetic material into human cells by interfering with the integrase enzyme.

Most persons with HIV infection are given drugs from more than one class, in case the HIV virus becomes resistant to a specific class of drugs.

Impact

According to WHO, over 2 billion people worldwide have been infected with HBV, and 250 to 300 million people live with HBV at any given time. It is estimated that 800,000 to one million people die each year from complications of HBV. HBV is endemic to China and much of Asia. It is most prevelant in Southeast Asia, Africa, and the Middle East, but it does impact individuals in Europe and North America.

WHO estimates that about 0.7 percent of the world’s population has been infected with HCV and around 50 million people are living with chronic HCV. According to WHO, in the United States, between 2.4 and 4.7 million people may be chronically infected with HCV. In Europe, as many as 12 million may be living with chronic HCV. In India, about 14 million people are estimated to have chronic HCV infection. Most do not know they are infected.

WHO estimates that there are 33.3 million people worldwide who are living with HIV. In 2023, there were 39.9 million people living with HIV, 1.3 million people became newly infected, and 630,000 individuals died from conditions related to AIDS.

Bibliography

American College of Emergency Physicians. Bloodborne Pathogens. 8th ed., Jones and Bartlett, 2022.

"Bloodborne Diseases." BCCDC, www.bccdc.ca/health-info/disease-types/bloodborne-diseases. Accessed 19 Dec. 2024.

"Bloodborne Infectious Disease Risk Factors." Centers for Disease Control and Prevention, www.cdc.gov/niosh/healthcare/risk-factors/bloodborne-infectious-diseases.html. Accessed 19 Dec. 2024.

Boyer, Thomas D., et al., editors. Zakim and Boyer’s Hepatology: A Textbook of Liver Disease. 7th ed., Saunders/Elsevier, 2018.

Everson, Gregory T., and Hedy Weinberg. Living with Hepatitis B: A Survivor’s Guide. Hatherleigh, 2002.

Everson, Gregory T. Living with Hepatitis C: A Survivor’s Guide. 5th ed., Hatherleigh Press, 2009.

Feldman, Mark, et al., editors. Sleisenger and Fordtran’s Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 11th ed., Saunders/Elsevier, 2021.