Infectious diseases, also known as transmissible or communicable diseases, are illnesses caused by a specific infectious agent such as a virus or bacteria, or its toxic products. Public health units across Ontario monitor these diseases since they have the potential to cause serious illness and can be transmitted to large numbers of individuals. As such, under provincial law, all cases of reportable diseases designated in Ontario’s Health Protection and Promotion Act (HPPA) (1), must be reported to local public health authorities (see Appendix B).
This is the second in a series of infectious disease reports for the Porcupine Health Unit (PHU). The report presents rates of reportable diseases between 2009 and 2014 for the Porcupine Health Unit area, provides a provincial comparison of rates, and includes a brief interpretation of the disease trends. The PHU uses this information to guide disease prevention and control efforts as well as health promotion, resource allocation and policy decisions.
Diseases are categorized by mode of disease transmission. Disease summaries are organized in alphabetical order following a standard format. Data was summarized for diseases with six or more reported cases cumulatively during the six-year study period. Diseases for which there were fewer than six reported cases in the PHU area during the study period are listed in the Rare Diseases Table of Appendix A.
Between 2009 and 2014, there were a total of 3,914 reported cases of infectious disease in the PHU area – or an average of 652.3 cases per year. This is higher than the average of 537.3 cases per year in the previous report (2006 to 2012). From 2009 to 2014, the local number of infectious disease cases decreased by 7.9% (rate of disease decreased by 6.1%) while provincially, cases increased by 27.2% (rate of disease increased by 21.5%).
The top three diseases — chlamydia, influenza, and gonorrhea — accounted for 87.1% of all cases. Chlamydia, by far, accounted for the largest proportion of cases (66.4%), followed by influenza at 12.7% of cases, and gonorrhea at 8.0% of cases.
Table 1 lists the number and proportion of all reportable diseases in the PHU area for which there were one or more cases during the six-year study period of 2009 to 2014.
Table 1. Number and proportion of all reportable diseases (with one or more cases), by rank, Porcupine Health Unit, 2009-2014 combined
|Rank||Disease||# of Cases||Proportion (%) of Cases|
|7||Invasive Pneumococcal Disease (IPD)||36||0.9|
|8||Invasive, Group A Streptococcal Disease (iGAS)||30||0.8|
|15||Human Immunodeficiency Virus (HIV)||5||0.1|
|15||Verotoxin producing E. coli (VTEC)||5||0.1|
|18||Invasive Meningococcal Disease (IMD)||2||0.1|
* Influenza data is seasonal from 2009-10 to 2014-15
^Syphilis includes infectious, non-infectious and unspecified cases
Source: iPHIS 2009-2014, MOHLTC, extracted May 2015
A total of 199 enteric illnesses (5.1% of all cases) were reported in the PHU area between 2009 and 2014. Salmonellosis, campylobacteriosis, and giardiasis accounted for 81.8% of these cases. This is similar to the ranking and proportion of enteric illnesses provincially. There were less than six reported cases cumulatively of each of cyclosporiasis, hepatitis A, shigellosis, verotoxin producing E. coli, yersiniosis, listeriosis, and typhoid/paratyphoid fever between 2009 and 2014.
For all enteric illnesses considered in this report, average local rates of disease were lower than average provincial rates of disease over the six-year study period. Females accounted for slightly more than half of cases locally.
Between 2009 and 2014, there were 46 enteric outbreaks (average of 7.7 per year) reported in the PHU area. This includes an outbreak of 13 cases of Clostridium Difficile Infection (CDI), which is rare, but occurred in a local hospital in 2009. Outbreaks occurred seasonally, peaking at an average of 1.8 outbreaks in March. The majority of these outbreaks occurred in long-term care homes and hospitals. Community outbreaks (8.7% of all enteric outbreaks) are likely underestimated since reporting of them to public health authorities is not required.
Between 2009 and 2014 in the PHU area, there were 5 reported cases of vector-borne and zoonotic diseases (0.1% of all cases). Four of these cases were of malaria and one of Lyme disease. Zero cases of rabies or West Nile Virus were reported. Provincially, malaria also represented the majority of reported cases.
Locally, there were 3,103 reported cases of sexually transmitted and blood-borne infections (79.3% of all cases) in the PHU area between 2009 and 2014. Chlamydia, gonorrhea, and hepatitis C accounted for 99.5% of all cases locally. Provincially, the ranking and proportion of these diseases were similar.
Local average incidence rates for chlamydia and gonorrhea were greater than the provincial average rates over the six-year study period. For hepatitis B and C, local average rates were similar to provincial average rates of disease. Finally, local average rates for HIV and syphilis (both infectious and non-infectious) were lower than provincial average rates. There were no cases of AIDS reported in the PHU area during the study period.
Males and females 15 to 24 years of age accounted for the largest proportion of these cases. Within this age group, females accounted for the majority of cases with rates two to three times the male rates.
Between 2009 and 2014 in the PHU area, there were 556 reported cases of vaccine preventable disease (14.2% of all cases). Influenza, invasive pneumococcal disease, and pertussis accounted for almost all of the cases both locally and provincially. Of these, influenza accounted for 89.6% of cases locally. There were no locally reported cases of measles and less than six cases each of invasive meningococcal disease and mumps during the study period.
While average local incidence rates for influenza and pertussis were higher than average provincial rates during the study period, local average rates for invasive pneumococcal disease were lower than average provincial rates.
Females accounted for slightly more than half of the vaccine preventable disease cases locally. By age group, adults over the age of 65 and children less than 5 years of age accounted for the greatest number of cases. These two populations are at higher risk for complications related to influenza and, therefore, may be tested more often, leading to higher reported rates.
During the six-year study period, there were 72 respiratory outbreaks in the PHU area. Twenty-five of these (34.7%) were influenza-related. These outbreaks were seasonal in nature, peaking in January. The vast majority of respiratory outbreaks occurred in long-term care homes, followed by hospitals and retirement homes.
The local average incidence rate for invasive Group A streptococcal disease was higher than the provincial average rate during the study period, while the local average rate for tuberculosis was lower than the provincial average rate. Males and adults 65 years of age and older accounted for the majority of cases locally, by sex and age group.
The Porcupine Health Unit Infectious Disease Status Report: 2009-2014 helps to fulfil the Porcupine Health Unit’s mandate under the Ontario Public Health Standards (2), to conduct disease surveillance and publicly report on findings. This is the second in a series of reports to the public on the local status of infectious disease. The PHU will use the findings from this report to inform public health programming. It is also hoped that this report will be useful for community agencies in the work that they do to support and enhance community health.