People who inject drugs (PWID) and Risk of Infectious Disease

Injecting Drug User 
Injecting drug use is widespread in developed countries; it has been estimated in 2008, that there are between 13,500 and 16,000 problem opiate users in Ireland, with more than three quarters of these living in the Greater Dublin region.

People who inject drugs (PWID) are at special risk of developing a range of infectious diseases because of the dangers posed by contaminated injection needles, syringes and drugs. In addition, PWIDs engage in risk-taking behaviour and tend not to look after their health, leaving them at risk of contracting diseases such as sexually transmitted infections and tuberculosis. Some PWIDs may have severely suppressed immune systems and be at risk of disease produced by microorganisms that do not normally cause disease in humans.

The following are infections associated with PWIDs:

  • Injection site infections: caused by bacteria such as staphylococci and streptococci. One of the most serious types of injection site infection is wound botulism, caused by Clostridium botulinum.
  • Bacterial bloodstream infections: caused by bacteria such as staphylococci and streptococci (but also rarer pathogens such as Pseudomonas and Serratia) and leading to conditions such as:
    • Endocarditis: complicated by the damaging effects of talc and other contaminants,
    • Pulmonary infections (including lung abscess and septic pulmonary emboli),
    • Bone and joint infections.
  • Viral Hepatitis: PWIDs are at increased risk of being exposed to Hepatitis B and Hepatitis C. Many PWIDs go on to develop chronic hepatitis and liver failure. PWIDs are also at increased risk of contracting Hepatitis A.
  • Anthrax: PWIDs may become infected with anthrax when heroin is contaminated with anthrax spores.
  • HIV: Sharing of dirty needles and other injecting paraphernalia is a major risk factor for HIV infection. HIV diagnoses are increasing among people who inject the drug snow blow.
  • Human T-Cell Leukaemia/Lymphoma: caused by HTLV-2 is more frequently reported in PWIDs that in the general population.
  • Tuberculosis: Tuberculosis tends to be endemic in PWIDs particularly those with weakened immune systems and especially in those infected with HIV.
  • Pneumocystis carinii pneumonia: this is much more common in PWIDs especially those living with HIV.
  • Toxoplasmosis: Toxoplasmosis is more common in severely immunosuppressed PWIDs.
  • Opportunistic viral infections: these include infections cases by Herpes simplex virus, Varicella-Zoster virus, cytomegalovirus and Epstein-Barr virus in PWIDs who have severe immunosuppression.

Last updated: 15 June 2016