A bloodborne disease is a disease that can be spread through contamination by blood and other body fluids. Bloodborne pathogens are microorganisms such as viruses or bacteria. The most common examples are HIV, hepatitis B and viral hemorrhagic fevers.
Diseases that are not usually transmitted directly by blood contact, but rather by insect or other vector, are more usefully classified as vector-borne disease, even though the causative agent can be found in blood. Vector-borne diseases include West Nile virus, zika fever and malaria.
Many bloodborne diseases can also be contracted by other means, including high-risk sexual behavior or intravenous drug use. These diseases have also been identified in sports medicine.
Since it is difficult to determine what pathogens any given sample of blood contains, and some bloodborne diseases are lethal, standard medical practice regards all blood (and any body fluid) as potentially infectious. Blood and Body Fluid precautions are a type of infection control practice that seeks to minimize this sort of disease transmission.