One of the most significant victories against ill health across Canada has been the dramatic reduction in infectious disease over the last century. Many Ontarians will have never experienced the devastation of a family member stricken with polio or measles. For most Ontarians, infectious disease is thought of primarily in terms of the upper respiratory tract infection known as the common cold.

Reductions in infectious disease in places like Ontario are due in part to improved living conditions and public utilities, particularly water and sanitation systems. However, as infections that are easily transmitted in substandard, crowded living conditions are reduced, a greater proportion of the total burden of infectious disease is due to blood-borne infections (BBI).

For this report, BBI refers to microbial organisms (viruses, bacteria and parasites) that are passed from human to human through blood or blood products. Humans can be exposed to BBI because of their behaviours (particularly sexual practices and drug use), injuries (e.g., needle stick injuries of healthcare workers), mother-to-child transmission during pregnancy, labour and delivery, insect bites for vector-borne infections, or as a consequence of receiving blood or blood products as part of the treatment for a health condition.

BBI, like all health conditions, have risk factors. In the same way that people who smoke face greater risks of heart disease than people who do not smoke, people who engage in certain behaviours face increased risks of BBI. However, because BBI are transmissible, because infected people may not know they are infected and thus unwittingly spread BBI, and because all Ontarians may have friends or family members at risk for BBI, BBI affect us all.

It may be tempting to imagine that protecting people from BBI acquired through blood transfusion is not at all related to protecting people from sexual transmission of BBI. On the contrary, reducing the burden of BBI in Ontario requires a comprehensive approach that can encompass multiple modes of transmission. For some BBI, large numbers of new infections occur in well-defined groups, such as drug users. Given that preventing new infections protects everyone, the health of all Ontarians is improved by implementing effective measures to prevent BBI, whether targeted to high-risk behaviours or the general population. Put another way, each prevented infection means a lower prevalence of BBI, which means fewer people infected. And if fewer people become infected, the episodic risk of transmission in any single exposure, whether blood transfusion, drug use, sexual contact or birth, is reduced.

Colin O. D'Cunha, MBBS, MHSc, FRCPC
Chief Medical Officer of Health

FULL REPORT 2003 Chief Medical Officer of Health Report :  Blood-borne Infections 33 pages | 996 K | PDF format

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November 2003