Blood-borne infections are diseases caused by viruses, bacteria or parasites that can be transmitted from one person to another through contact with contaminated blood or certain body fluids. When infected blood enters another person’s bloodstream via a wound, mucous membrane or needlestick injury, the pathogens it contains may establish infection.
Explanation
The term blood-borne covers a wide range of infectious agents. Among viruses, human immunodeficiency virus (HIV) and hepatitis B and C viruses are the most prevalent. HIV attacks the immune system and leads to AIDS if untreated. Hepatitis B and C infect liver cells and can cause chronic liver disease and cancer. Other viral agents such as West Nile virus and certain haemorrhagic fevers may also be spread by blood. Bacteria and parasites can be blood-borne too; syphilis is caused by the spirochaete Treponema pallidum and malaria is transmitted through blood via mosquito bites or transfusions. Transmission typically occurs through needle sharing among people who inject drugs, transfusion of unscreened blood, reuse of contaminated medical instruments, accidental needlestick injuries in health‑care workers, or mucous membrane exposure. Many blood-borne pathogens are also sexually transmitted, so unprotected sex is another route of infection. Vertical transmission from mother to child can occur during pregnancy, birth or breastfeeding.
Key Pathogens and Prevention
HIV is a retrovirus that targets CD4+ T‑cells; treatment with antiretroviral therapy suppresses viral replication and reduces transmission risk. Hepatitis B is preventable by vaccination; its virus is resistant to environmental degradation and remains infectious outside the body for days. Hepatitis C has no vaccine, but direct‑acting antivirals can cure most infections. Prevention of blood-borne infections hinges on screening blood donations, sterilising medical equipment, using disposable syringes, and practising standard precautions such as wearing gloves and goggles when handling blood. Harm‑reduction services like needle exchange programmes decrease the risk among drug users. In sexual transmission, barrier methods and treatment of infected partners reduce spread. Post-exposure prophylaxis with antivirals or immunoglobulins may be offered after high‑risk exposures. Public health measures and education continue to lower transmission rates, but vigilance remains essential.
Blood-borne infections illustrate how pathogens exploit breaches in the circulatory system to move between hosts. Advances in screening and treatment have made many of these diseases manageable or preventable, yet safe practices in health care and personal behaviour remain the cornerstone of control.
Related Terms: Blood transfusion, Pathogen, Hepatitis, HIV, Needle stick injury