Try the new Beta.Halton.ca

2017 Halton Region Infectious Disease Report

This report summarizes the incidence of infectious (communicable) diseases that were reported to the Health Department for Halton Region residents in 2017, as well as outbreaks investigated by the Halton Region Health Department in 2017.

Background

The Halton Region Health Department works towards the goal of reducing the incidence of infectious diseases in the community through a variety of programs and services, including investigating individual cases and responding to outbreaks, inspecting retail food services and personal service settings, health promotion campaigns, and providing immunizations and other clinical services.

Reportable infectious diseases are diseases that are required under the Health Protection and Promotion Act to be reported to the local Medical Officer of Health. The 2017 Halton Region Infectious Disease Report summarizes the incidence of infectious diseases that were reported to the Health Department for Halton Region residents in 2017. The report also describes outbreaks investigated by the Halton Region Health Department in 2017. This report reflects the surveillance and health status report function that the Health Department is mandated to perform in to monitor the impact of infectious disease programs and to identify significant or emerging issues.

Key Findings

In 2017, 2,475 cases of reportable infectious diseases were reported to the Halton Region Health Department.

The top five most common reportable infectious diseases in Halton in 2017 were:

  1. Chlamydial infections
  2. Influenza
  3. Gonorrhoea
  4. Campylobacter enteritis
  5. Salmonellosis

Vaccine-preventable diseases are diseases for which an effective vaccine exists. In 2017, 500 Halton residents were diagnosed with a vaccine-preventable disease, accounting for 20% of all reportable diseases that year. Age-standardized rates of vaccine-preventable diseases in 2017 were similar or lower in Halton compared to Ontario. The most commonly reported vaccine-preventable disease was influenza (439 cases); however the true number of influenza cases in the population is likely to be much higher, as many people may not seek medical treatment or receive laboratory testing for influenza and therefore cases are not reported.

Food- and water-borne diseases are caused by bacteria, parasites, and viruses that have found their way into food or water that is being consumed. In 2017, there were 392 reported cases of food and water-borne diseases among Halton residents, accounting for 16% of the total cases of reportable infectious diseases that year. The most commonly reported food- and water-borne diseases in 2017 were Campylobacter enteritis (152 cases) and salmonellosis (114 cases). Age-standardized rates of food- and water-borne diseases in Halton were similar or lower compared to Ontario. In 2017, 41% of food- and water-borne illnesses with a known risk factor/exposure in Halton were associated with travel outside of Canada.

Sexually-transmitted and blood-borne infections are the most common category of reportable infectious diseases in Halton. In 2017, there were 1,479 reported cases of sexually-transmitted infections (STIs) and blood-borne infections among Halton residents, accounting for over half (60%) of all reportable diseases in Halton. Chlamydia was the most commonly reported infectious disease in Halton (1,148 cases). Other common STIs and blood-borne infections include gonorrhoea (179 cases) and hepatitis C (102 cases). In general, rates of STIs and blood-borne infections are lower in Halton compared to Ontario. In recent years, Halton has seen an increase in reported cases of gonorrhoea and chlamydia, consistent with the overall trend in Ontario.

Reportable neonatal infectious diseases are transferred from mother to infant either through the placenta, or through the birth canal during delivery. In 2017, there were two cases of reportable neonatal disease.

Zoonotic diseases are diseases that can be passed from animals to humans. Vector-borne diseases are spread to people by small organisms such as mosquitoes and ticks. In 2017, there were 26 cases of zoonotic or vector-borne diseases reported in Halton, accounting for just over 1% of all reportable diseases. The most commonly reported vector-borne disease was Lyme disease (13 cases). Halton had six reported cases of West Nile virus illness in 2017, which was similar to the previous five year average (6 cases).

There were an additional 77 cases of other reportable diseases (meningitis/encephalitis, group A streptococcal disease, tuberculosis, meningococcal disease, and Cruetzfeldt-Jakob disease) reported to the Halton Region Health Department in 2017, accounting for 3% of all reportable diseases in Halton. Rates of encephalitis/meningitis combined in Halton in 2017 were significantly higher than Ontario. Rates of tuberculosis in Halton in 2017 were significantly lower than Ontario.

Infectious diseases and the social determinants of health

Social determinants of health reflect the social and physical conditions where people live, learn, work, and play. Due to the influence of the social determinants of health, the burden of infectious disease is not evenly distributed across the population. In 2017, the rate of reportable infectious diseases in Halton was highest in the low neighbourhood income group. However, in Halton, there are very few neighbourhoods in Halton that are considered to be in the low income group. Therefore, although the rate of reportable infectious diseases was highest in the low neighbourhood income group, there were only 124 cases reported, compared to 1650 cases reported in the high neighbourhood income group.

Outbreak investigations

Halton Region Health Department staff members investigate outbreaks in order to decrease or eliminate health risks presented by infectious diseases. All institutional enteric and respiratory outbreaks are reportable to the Health Department, regardless of whether or not the specific disease is known or reportable.

In 2017, there were 85 confirmed and suspect respiratory institutional outbreaks investigated by the Health Department. The majority of respiratory outbreaks investigated by the Health Department involved long-term care homes (72%), followed by retirement residences (18%), unregulated or special homes (4%), child care centres (2%), community settings (2%), and hospitals (2%). The most common agents were influenza A (35%), unspecified respiratory agents (20%), and rhinovirus (8%).

In 2017, there were 44 confirmed enteric institutional outbreaks investigated by the Health Department. The majority of enteric outbreaks investigated by the Health Department occurred in child care centres (45%), followed by long-term care homes (30%), retirement residences (20%), and community settings (5%). Over half the agents involved in enteric outbreaks were unspecified (61%), but the most common known agent was norovirus (32%).