Injecting Drug Users (IDUs) and Risk of Infectious Disease

 
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.

Injecting drug users (IDUs) 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, IDUs 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 IDUs 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 IDUs:

• 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: IDUs are at increased risk of being exposed to Hepatitis B and Hepatitis C. Many IDUs go on to develop chronic hepatitis and liver failure. IDUs are also at increased risk of contracting Hepatitis A.
• HIV: Sharing of dirty needles and other injecting paraphernalia is a major risk factor for HIV infection.
• Human T-Cell Leukaemia/Lymphoma: caused by HTLV-2 is more frequently reported in IDUs that in the general population.
• Tuberculosis: Tuberculosis tends to be endemic in IDUs particularly those with weakened immune systems and especially in those infected with HIV.
• Pneumocystis carinii pneumonia: this is much more common in IDUs especially those living with HIV.
• Toxoplasmosis: Toxoplasmosis is more common in severely immunosuppressed IDUs.
• Opportunistic viral infections: these include infections cases by Herpes simplex virus, Varicella-Zoster virus, cytomegalovirus and Epstein-Barr virus in IDUs who have severe immunosuppression.