A handful of infectious diseases that can be as common as a cold or as potentially deadly as AIDS have a devastating effect on the lives of Ontarians, a new study finds.
The study released by the Ontario Agency for Health Protection and Promotion (OAHPP) and the Institute for Clinical Evaluative Sciences (ICES) finds that nearly 5,000 Ontarians die every year from infectious diseases.
Some of the diseases that cause the most health problems in the province are well-known, but others get little recognition in terms of public awareness or funding for research.
For example, West Nile virus and Listeria have received extensive media attention in recent years, yet they caused only a mild health burden in terms of the number of patients affected and death rates. Streptococcus pneumoniae, on the other hand, is responsible for a huge number of deaths each year, yet gets little media attention.
Dr. Jeff Kwong, a scientist at ICES who helped lead the research says the study was undertaken so that researchers and the public could better understand which diseases affects the health of Ontarians the most every year.
"Infectious diseases are not going away, and we as a society need to realize the impact of a number of these diseases," Kwong said in a news release.
The study reviewed data on 51 infectious diseases and found that the 10 pathogens that carry the heaviest health burden for Ontarians were:
• Hepatitis C virus – This infection took the top spot because even though only about 370 people die in Ontario every year from it, hep C tends to infect young people and causes devastating and lifelong effects, such as liver cirrhosis and liver cancer.
• Streptococcus pneumoniae – This bacterial infection is the leading cause of pneumonia and meningitis, especially among the elderly in nursing homes, and is responsible for a huge number of deaths each year. A vaccine that can protect against 23 types of the bacteria.
• Human papillomavirus (HPV) – A common infection, certain strains of HPV are thought to cause the majority of cervical cancer as well as anal cancer and genital warts. The virus causes about 250 deaths and about 1,000 new cases of cancer in Ontario annually.
• Hepatitis B virus - Transmitted by sexual contact, injection drug use, or other ways, hep B can cause liver diseases, and is estimated to be responsible for about 350 deaths a year in Ontario.
• Escherichia coli (E. coli) – Most strains of E. coli bacteria are harmless bacteria, but certain strains can produce deadly gastrointestinal and urinary tract infections. About 450,000 cases of infection in Ontario require medical attention each year.
• Human immunodeficiency virus (HIV/AIDS) – While HIV is not as common in Ontario as it is in other parts of the world, the infection creates a huge health burden for those carrying the virus who have to take medication to control the infection for the rest of their lives. There is no vaccine and no cure.
• Staphylococcus aureus – These bacteria are the main cause of hospital-acquired infection, causing about 270 deaths and about 160,000 infections requiring sometimes intensive medical care each year in Ontario.
• Influenza – A commonly aquired infection, affecting about 630,000 Ontarians every year, the virus can also be deadly in some and causes about 270 deaths annually.
• Clostridium difficile - A bacterium that causes severe and potentially fatal diarrhea, almost all cases of C. diff are acquired in health-care institutions, particularly in those who have been treated with antibiotics. The pathogen causes about 170 deaths a year as well in Ontario as more than 5,000 cases that require hospital treatment.
• Rhinoviruses (common cold) – Rhinoviruses are the single most common form of infection in humans. Though it's rarely fatal, more than 1.6 million cases require medical attention every year.
The researchers note that for many of the infections listed, vaccines to prevent infection already exist, such as for hepatitis B and influenza. Other methods exist to prevent other infections, such as using condoms to reduce the risk of acquiring HIV.
"These results provide a crude ordering of infectious diseases that can be used to guide planning and policy related to public health and clinical services, as well as future research across the spectrum from basic sciences to clinical services to epidemiology and population health," the authors write.
"These findings show where and how we should be concentrating our efforts to get the greatest impact in improving the health of Ontarians," said Dr. Natasha Crowcroft, director of surveillance and epidemiology at OAHPP, in a statement.
"Improvements range from concentrating on immunization programs where vaccinations exist, such as for human papillomavirus, through increasing screening and access to treatment for hepatitis B and C, to developing new ways to fight infectious diseases."
The authors also note that with Ontario's relatively large population size (over 13 million representing approximately 40 per cent of the Canadian population), the findings likely apply to all of Canada.
