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Modes of Transmission

Bloodborne pathogens such as HBV, HCV and HIV can be transmitted through contact with infected human blood and other potentially infectious materials (OPIM) as defined below.
Blood is defined as human blood, human blood components and products made from human blood. Also included in this definition are medications derived from blood, such as immune globulins, albumin, and factors 8 and 9.
OPIM includes all of the following:

  • Human body fluids: semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, peritoneal fluid, amniotic fluid, saliva in dental procedures, any body fluid that is visibly contaminated with blood, and all body fluids in situations where it is difficult or impossible to differentiate between body fluids.
  • Any unfixed tissue or organ (other than intact skin) from a human (living or dead). Human cell lines are considered OPIM if they can or do carry bloodborne pathogens. Some cell lines have been tested and certified by the suppliers to be free of bloodborne pathogens. Fixed human tissues are not potentially infectious with bloodborne pathogens and therefore are not considered OPIM.
  • HIV-containing cell or tissue cultures, organ cultures, and HIV- or HBV-containing culture medium or other solutions; and blood, organs, or other tissues from experimental animals infected with HIV or HBV.
  • Blood and tissues of experimental animals infected with bloodborne pathogens.

It is important to know the ways exposure and transmission are most likely to occur in your particular situation, be it providing first aid to a student, handling human cells in the laboratory, or cleaning up blood from a hallway. Consult your Bloodborne Pathogens Exposure Control Plan or your supervisor for this information.

Bloodborne pathogens are most commonly transmitted through:

  • Accidental puncture from contaminated needles, broken glass, or other sharps
  • Contact between broken or damaged skin and infected body fluids
  • Contact between mucous membranes and infected body fluids
  • Sexual Contact
  • Sharing of hypodermic needles
  • From mothers to their babies at/before birth

In most work or laboratory situations, transmission is likely to occur because of accidental puncture from contaminated sharps or contact between broken skin or mucous membranes and infected body fluids. Anytime there is blood-to-blood contact with infected blood or body fluids, there is a potential for transmission.

Unbroken (intact) skin forms an impervious barrier against bloodborne pathogens; therefore, blood getting on intact skin is not considered an exposure risk.
However, infected blood can enter your system through:

  • Open sores
  • Cuts
  • Abrasions
  • Acne
  • Any sort of damaged or broken skin such as sunburn, chapped skin or blisters

Bloodborne pathogens may also be transmitted through the mucous membranes such as in the:

  • Eyes
  • Nose
  • Mouth

For example, a splash of contaminated blood to your eye, nose, or mouth is considered an exposure event and could result in transmission.

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