Blood-Borne Viruses

Abstract

Blood- borne viruses (BBVs) are viral infections transmitted by blood or body fluid. In practice, any viral infection that achieves a high viral load in blood or body fluid can be transmitted through exposure to infected biological materials. In western countries, the most significant BBVs are human immunodeficiency viruses (HIV1 and HIV2), hepatitis B virus (HBV) and hepatitis C virus (HCV). Other viruses that can be transmitted by blood and body fluid include human T cell lymphotropic viruses (HTLV1 and HTLV2), cytomegalovirus, West Nile virus and viruses responsible for viral haemorrhagic fever such as Ebola virus, Lassa virus, and Crimean-Congo haemorrhagic fever virus. BBVs are transmitted via exposure to blood and body fluid. Some examples of routes of transmission include: ● Sharing needles in people who inject drugs (PWID); ● Medical re-use of contaminated instruments (common in resource poor settings); ● Sharps injuries in healthcare setting, including in laboratories (less commonly through mucosal exposure); ● Transfusion of blood contaminated with BBVs (failure to screen blood donors); ● Transplantation of organs from BBV-infected donors; ● Sexual exposure to BBV-infected body fluid; and ● Exposure to maternal BBV infection: intrauterine, perinatally, or postnatally. If exposure to a BBV is via a needle stick injury in a healthcare setting, immediate first aid needs to be carried out by gently encouraging bleeding and washing the exposed area with soap and water. Prompt reporting of the incident is required so that an assessment can be done as soon as possible to determine if post-exposure prophylaxis (PEP) is required. The decision may be aided by urgent assessment of source patient infection status. The British Medical Association has issued guidance for testing adults who lack the capacity to consent. In the case of a sexual exposure to a BBV, immediate consultation to a genito-urinary medicine (GUM) clinic is warranted. The risk of transmission of BBVs associated with exposure depends on the nature of the exposure and the body fluid involved. The following factors are important in needle stick injuries: ● Deep percutaneous injury. ● Freshly used sharps. ● Visible blood on sharps.