Understanding Bloodborne Pathogens and Their Role in Infection

Bloodborne pathogens are viruses and bacteria that are found in the blood and can be transmitted via blood. Not all infections are transmitted in this way. Some, like herpes and HPV, are spread from skin to skin rather than through blood and other bodily fluids. Others can be transmitted through coughing and sneezing or through contact with contaminated food.

Some bloodborne pathogen may also be transmitted in other ways, such as by exposure to semen, urine, or saliva. Sometimes this is because small amounts of blood may be present in these fluids. Other times, it's because the virus or bacteria isn't restricted to growing and living in blood. That is why it is always a good idea to be cautious when handling bodily fluids. When in doubt, assume they are infected and take proper precautions — such as by following universal precautions.

Technician holding blood vial
Tom Grill / Getty Images

What Are Universal Precautions?

Universal precautions are techniques used in health care and other settings that are designed to reduce the transmission of bloodborne pathogens. Basically, they say that professionals who are at risk of coming into contact with blood, or other potentially infectious bodily fluids, should do what they can to avoid touching blood, and blood products with their bare hands. Instead, gloves should be used whenever possible. It is also important to wash hands well after any contact with blood or other bodily fluids, even when you're changing your gloves between contacts. People might also wear masks or gowns if there is a risk of spraying fluids.

Despite the need for universal precautions, most bloodborne pathogens, such as HIV, cannot be spread through casual contact. Casual contact is much more of a risk with airborne infections, including those that spread through droplets, such as the common cold. That's another reason why frequent hand washing is a good idea. A cold may not seem like as big a problem as an HIV infection, but it's a much more frequent one.


HIV is a bloodborne pathogen. So is hepatitis C. That is one reason that there is a high risk for transmission of these diseases when injection drug users share needles. The needles and syringes used when injecting drugs can become contaminated with blood. Then that blood can be injected, along with the drugs, into the next person who uses the needle or syringe.

One way that governments have intervened to reduce the frequency of bloodborne disease transmission among people who inject drugs is to set up needle exchange programs. These programs allow drug users to pick up free, sterile needles and syringes and also drop off old "works" for safe disposal. Needle exchange programs are often controversial, even though research has consistently shown that they do not increase injection drug use — just help to make it safer.

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By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.