Halton Region Health Department Infectious Disease Report

Transcription

1 Halton Region Health Department Infectious Disease Report 214

2 Reference: Halton Region Health Department, Infectious Disease Report. Oakville, Ontario, July 215. Author: Joanna Oliver, Epidemiologist, Halton Region Health Department Acknowledgements: Carley Aubin, Epidemiologist, Halton Region Health Department Catherine Bannan, Manager of Sexual Health/Needle Exchange Program, Halton Region Health Department Megan Hempel, Health Analyst, Halton Region Health Department Kathy Jovanovic, Manager Communicable Diseases, Halton Region Health Department Dimitra Kasimos, Manager Enteric and Vectorborne Disease, Halton Region Health Department Jason Letchford, Data Analyst, Halton Region Health Department Matthew Ruf, Director of Health Protection Services, Halton Region Health Department Emma Tucker, Senior Epidemiologist, Halton Region Health Department 214 Halton Region Infectious Disease Report

3 Table of Contents 214 Halton Region Infectious Disease Report... 1 Presentation of the Results... 1 Part I: Leading Reportable Infectious Diseases in 214 in Halton... 2 Comparison with Ontario Age-standardized Incidence Rates for Part II: Categories of Infectious Diseases... 6 Vaccine-Preventable Diseases... 6 Influenza 8 Streptococcus pneumoniae 9 Chickenpox 1 Food- and Water-borne Diseases Campylobacter enteritis 14 Giardiasis 15 Salmonellosis 16 Sexually-Transmitted Infections Chlamydia 18 Gonorrhoea 2 Syphilis 21 Select Blood-borne Infections Hepatitis C 24 Hepatitis B 25 Select Bacterial Diseases Transmitted by Direct Personal Contact or Respiratory Routes Tuberculosis 28 Group A Streptococcal Infections 3 Diseases Transmitted by Insects and Animals Other Reportable Infectious Diseases Encephalitis and Meningitis 33 Part III: Hospital Utilization...34 Infectious Diseases Emergency Department Visits Infectious Diseases Hospitalizations Part IV: Outbreak Investigations...38 Outbreaks by Location Respiratory Outbreaks Enteric Outbreaks Outbreak Trends Number of Cases Investigated Appendix A: O. Reg 559/91 under the Health Protection and Promotion Act...46 Appendix B: The Number of Reported Cases of Communicable Disease in 214 compared to 213 and the previous 5-year average (29 213), and the Age- Standardized Rates per 1, Population, Halton residents Appendix C: Summary of rare reportable infectious diseases and those with low incidence, Halton residents, Halton Region Infectious Disease Report

4 List of Figures Figure 1: The 1 most frequently reported infectious diseases compared to previous five-year annual average, Halton residents, Figure 2: Most frequently reported vaccine-preventable diseases compared to previous fiveyear annual average, Halton residents, Figure 3: Influenza, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 4: Invasive Streptococcus pneumoniae, age-standardized incidence rates per 1, population, Halton residents Figure 5: Chickenpox (varicella), total number of ED visits in Halton and age-standardized rates of emergency department visits, Halton residents compared to Ontario, Figure 6: Proportion of emergency department visits attributed to chickenpox, by age group, Halton and Ontario, Figure 7: Most frequently reported food- and water-borne diseases compared to previous five-year annual average, Halton residents, Figure 8: Campylobacter enteritis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 9: Giardiasis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 1: Salmonellosis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 11: Sexually-transmitted infections compared to previous five-year annual average, Halton residents, Figure 12: Chlamydia, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 13: Gonorrhea, age-standardized incidence rates per 1, population, Halton residents compared to Ontario Figure 14: Number of cases of syphilis compared to previous five-year annual average, Halton residents, Figure 15: Infectious and non-infectious syphilis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 16: The number of selected blood-borne infections compared to previous five-year annual average, Halton residents, Figure 17: Hepatitis C, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 18: Hepatitis B infection, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 19: Number of cases of selected bacterial diseases spread by close contact or respiratory routes compared to previous five-year annual average, Halton residents, Figure 2: Number of cases of tuberculosis compared to the previous five-year annual average, Halton residents, Figure 21: Tuberculosis (infectious only), age-standardized incidence rate per 1, population, Halton residents compared to Ontario, Figure 22: Severe group A streptococcal infections, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 23: Number of cases of diseases spread by arthropods compared to previous five-year annual average, Halton residents, Halton Region Infectious Disease Report

5 Figure 24: Number of cases of meningitis and enchephalitis compared to previous five-year annual average, Halton residents, Figure 25: Encephalitis and Meningitis combined, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Figure 26: Emergency department visits attributed to infectious diseases, number of visits and age-standardized rates per 1, population, Halton residents, Figure 27: Emergency department visits attributed to infectious diseases, age-specific rates, Halton residents, combined Figure 28: Emergency department visits attributed to infectious diseases, age-standardized rates, by neighbourhood income group, Halton residents, combined...35 Figure 29: Hospitalizations attributed to infectious diseases, number of visits and agestandardized rates per 1, population, Halton residents, Figure 3: Hospitalizations attributed to infectious diseases, age-specific rates, Halton residents, combined Figure 31: Hospitalizations attributed to infectious diseases, age-standardized rates, by neighbourhood income group, Halton residents, combined Figure 32: Type of outbreak by municipality, Halton Region, Figure 33: Outbreaks by type of location, Halton Region, Figure 34: Proportion of respiratory outbreaks by causative agent (laboratory-confirmed or suspected), Halton Region, Figure 35: Proportion of enteric outbreaks by causative agent (laboratory-confirmed or suspected), Halton Region, Figure 36: Number of outbreaks by type and month of onset, Halton Region, Figure 37: Number of outbreaks by type and duration, Halton Region, Halton Region Infectious Disease Report

6 List of Tables Table 1: Number, crude incidence rates, and age-standardized incidence rates of the top ten most frequently reported infectious diseases in Halton in 214 compared to reports for same diseases in the previous two years Table 2: Age-standardized incidence rates per 1, population for the top ten most frequently reported infectious diseases, Halton and Ontario, Table 3: Number of outbreaks, by type of outbreak and location, Halton Region, Table 4: Number of outbreaks by location, Halton Region, Table 5: Total number of clients and staff who were at risk and who were ill, by location of the outbreak, respiratory and enteric outbreaks combined, Halton Region, Halton Region Infectious Disease Report

7 214 Halton Region Infectious Disease Report The 214 Halton Region Infectious Disease Report summarizes the incidence of infectious (communicable) diseases that were reported to the Health Department for Halton Region residents in 214. These diseases are caused by a variety of organisms including bacteria, viruses, and protozoa, or by toxins from these organisms. Infectious diseases are spread from one host to another by close personal contact, sexual contact, contaminated food or water, animals, or other environmental sources. The current list of infectious diseases that must be reported to the local medical officer of health under the Health Protection and Promotion Act (HPPA) are shown in Appendix A. Outbreaks of any infectious diseases must also be reported. The 214 Halton Region Infectious Disease Report reflects the surveillance and health status reporting function that the Health Department is mandated to perform in order to monitor the impact of infectious disease programs and to identify significant or emerging issues. The Health Department works towards the goal of reducing the incidence of infectious diseases in the community through the delivery of various programs. Staff members investigate reports of individual cases and respond to outbreaks in both the community and in institutions such as long-term care homes, acute care settings, child care settings, schools, colleges, and correctional institutions. In addition to investigating disease reports and preventing further spread of disease, the Health Department also conducts inspections of licensed child care settings, personal services settings, food premises, small drinking water systems, and public spas and swimming pools. Finally, the Health Department is mandated to provide education and certification programs, such as food handler training, as well as clinical services, such as immunization and sexual health clinics, which help to prevent and reduce the burden of infectious diseases. Presentation of the Results Part I of this report provides an analysis of the 1 most frequently reported infectious diseases among Halton residents, along with comparisons to the last two years of data (212 and 213), the previous five-year annual average, and the ten-year trend, as well as comparisons to Ontario overall. Part II of the report summarizes all cases of reportable infectious diseases, grouping these into categories based on major immunization strategies (e.g., vaccinepreventable diseases) and main modes of transmission. Part III of the report summarizes hospital utilization attributed to infectious diseases. Part IV of the report presents an analysis of all the outbreaks that were investigated by the Halton Region Health Department during 214. Appendix B presents a complete list of the reported cases of infectious disease in 214 and the corresponding age-standardized incidence rates for 214 and 213. Significant changes in rates from 213 are indicated by up or down arrows. Appendix C presents a summary of rare reportable infectious diseases with low incidence or no reported cases in Halton Region Infectious Disease Report 1

8 Part I: Leading Reportable Infectious Diseases in 214 in Halton In 214, 2,61 cases of reportable infectious diseases were reported to the Halton Region Health Department for investigation (Table 1). Table 1 shows the 1 most frequently reported infectious diseases that accounted for 89% of the total cases. Figure 1 shows the number of cases of these diseases in 214 compared to the previous five-year annual average. In 213 and 212 there were 1,779 and 1,789 cases of reported infectious diseases, respectively. Please note that this report is based on reports of infectious diseases for the calendar year 214, but that influenza numbers are reported for the influenza season which begins in September of the previous year (213) and ends in August of the current calendar year on which this report is based (214). 214 Halton Region Infectious Disease Report 2

9 Table 1: Number, crude incidence rates, and age-standardized incidence rates of the top ten most frequently reported infectious diseases in Halton residents, 214 compared to reports for same diseases in the previous two years. Disease Total Reported Confirmed Cases Crude Incidence Rate per 1, Standardized 1 Incidence Rate per 1, Total Reported Confirmed Cases Crude Incidence Rate per 1, Standardized 1 Incidence Rate per 1, Total Reported Confirmed Cases Crude Incidence Rate per 1, Standardized 1 Incidence Rate per 1, Chlamydia Influenza Gonorrhea Campylobacter enteritis Salmonellosis Hepatitis C Giardiasis Streptococcus pneumoniae - invasive Encephalitis and 3 meningitis Streptococcal infections, group A Total Number of Reported Confirmed Cases Top 1 in each year 1, , , All Other Reported Cases TOTAL NUMBER OF REPORTED CASES 2,61 1,779 1,781 Notes: 1. Rates were age-standardized to the 1991 Canadian Population. 2. Influenza numbers are provided for the Influenza Season of Sept. 1 st to Dec. 31 st of the previous year and Jan. 1 st to Aug. 31 st of the current year. 3. This excludes bacterial meningitis. Source: Integrated Public Health Information System [ ], extracted March 23, 215; Population Estimates, IntelliHealth, Ontario Ministry of Health and Long-Term Care [213], extracted March 21, Halton Region Infectious Disease Report 3

10 Disease Figure 1 shows the same 1 most frequently reported infectious diseases. The numbers of cases for 214 are compared to the average number of cases per year in the previous five years, 29 to 213. Chlamydia Influenza Gonorrhea Campylobacter enteritis Salmonellosis Hepatitis C Giardiasis Streptococcus pneumoniae - invasive Encephalitis and meningitis* Streptococcal infections, Group A Number of reported cases annual average Figure 1: The 1 most frequently reported infectious diseases compared to previous five-year annual average, Halton residents, 214. Notes: Influenza numbers are provided for the Influenza Season of Sept. 1 st to Dec. 31 st of the previous year and Jan. 1 st to Aug. 31 st of the current report year. (*) This excludes bacterial meningitis. Source: Integrated Public Health Information System [29-214], extracted March 23, 215. Of the ten most frequently reported infectious diseases among Halton residents in 214, chlamydia and gonorrhea are sexually transmitted infections; influenza and Streptococcus pneumoniae are respiratory infections; campylobacter enteritis, salmonellosis and giardiasis are food and water-borne diseases; hepatitis C is a blood-borne infection; and group A streptococcal infection and encephalitis/meningitis is transferred by close contact. Influenza and Streptococcus pneumonia, and certain subtypes of meningitis, are vaccine preventable diseases. The full list of reportable infectious diseases for Ontario in 214 is provided in Appendix A. Appendix B presents a complete list of the reported cases of infectious disease in 214 and the corresponding age-standardized incidence rates for the current and previous year (213). 214 Halton Region Infectious Disease Report 4

11 Comparison with Ontario Age-standardized Incidence Rates for 214 In 214 there were some differences between the age-standardized incidence rates of the 1 most frequently reported infectious diseases in Halton as compared to Ontario (Table 2). The standardized incidence rates of chlamydia, gonorrhea, and hepatitis C were statistically significantly lower in Halton residents compared to Ontario. There were no statistically significant differences, between Halton and Ontario in the incidence of influenza, campylobacter enteritis, salmonellosis, giardiasis, Streptococcus pneumoniae, or group A streptococcal infections. The standardized incidence rate of encephalitis and meningitis was statistically significantly higher for Halton residents compared to Ontario. Halton had 36 cases of encephalitis and meningitis reported in 214, which is similar to the number of cases reported annually since 21, and the cases appear to be unrelated. Appendix B presents a complete list of the reported cases of infectious disease in 214 and the corresponding age-standardized incidence rates for Halton. Table 2: Age-standardized incidence rates per 1, population for the top ten most frequently reported infectious diseases, Halton and Ontario, 214. Disease HALTON 214 Age-standardized incidence rate per 1, (95% CI) ONTARIO 214 Age-standardized incidence rate per 1, (95% CI) Agestandardized Incidence Ratio (95% CI) Halton compared to Ontario 2 Chlamydia 18.7 ( ) 299. ( ).6 ( ) Influenza ( ) 68.8 ( ).97 ( ) Gonorrhea 27.8 ( ) 48.1 ( ).58 ( ) Campylobacter enteritis 22.9 ( ) 27.3 ( ).86 (.71-1.) Salmonellosis 22.4 ( ) 23.8 ( ).94 ( ) Hepatitis C 18.9 ( ) 29.7 ( ).63 ( ) Giardiasis 8.2 ( ) 9.7 ( ).9 ( ) Streptococcus pneumoniae ( ) 6.4 (6.-6.8) 1. ( ) invasive Encephalitis and 3 meningitis 6.7 (4.5-9.) 4.3 ( ) 1.6 ( ) Streptococcal infections, group A 4.2 ( ) 4.8 ( ).81 ( ) Notes: (1) Influenza data for Ontario is for the season (calculated as of Sept. 1st to Dec. 31st of previous year and Jan. 1st to Aug. 31st of the year of reporting). (2) Comparison between Halton residents and Ontario: ( ) indicates that there was no statistically significant difference between Halton and Ontario; ( ) indicates that the age-standardized incidence rate in Halton was significantly lower than Ontario; and, ( ) indicates that the age-standardized incidence rate in Halton was significantly higher than Ontario. If the confidence interval (CI) range for the age-standardized Incidence Ratio contains one, the differences were not statistically significant between Halton and Ontario; if the CI range was below one Halton has a statistically significantly lower rate than Ontario; and if the CI range was above 1 Halton has a statistically significantly higher rate than Ontario. (3) This excludes bacterial meningitis. Sources: Integrated Public Health Information System [215], extracted March 23, 215; Population Estimates, IntelliHealth, Ontario Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 5

12 Part II: Categories of Infectious Diseases The data in this section of the report are presented under the following six categories: 1. Vaccine Preventable Diseases 2. Food- and Water-borne Diseases 3. Sexually-transmitted Infections 4. Blood-borne Infections 5. Diseases Transmitted by Direct Personal Contact and Respiratory Routes 6. Diseases Transmitted by Insects and Animals The numbers of reported cases for Halton residents are shown, along with comparisons to the previous five-year annual average. Age-standardized incidence rates are also included allowing for comparison to the province and other health regions. Vaccine-Preventable Diseases Immunization has played a key role in reducing the burden of many diseases and has even eradicated (i.e., world-wide) or eliminated (e.g., continent-wide) some diseases that in the past century have caused major illness and loss of life. Illnesses from nine infectious diseases (i.e., smallpox, diphtheria, pertussis, tetanus, polio, measles, mumps, rubella, and H. influenzae type b) have decreased substantially or been eliminated entirely in North America. Ontario children under the age of six now receive immunization against 12 diseases. Some vaccines require only a single dose, some require multiple doses over a period of years; some are available combined, others must be given separately. Because vaccines have different levels of effectiveness and/or do not cover all strains/sub-types of the organisms at which they are aimed, not all vaccines are equally effective. Also, coverage of the population is not 1%. This is why it is important to monitor the incidence of vaccine-preventable diseases. In 214, 45 Halton residents were diagnosed with vaccine-preventable diseases, accounting for 22% of the total cases of reportable infectious diseases that year (Appendix B). Figure 2 shows the number of cases of vaccine-preventable diseases in Halton residents in 214 compared to the previous five-year annual averages. 214 Halton Region Infectious Disease Report 6

13 Number of reported cases Influenza 41 Streptococcus pneumoniae - invasive Pertussis Measles Mumps Disease Annual Average Figure 2: Most frequently reported vaccine-preventable diseases compared to previous fiveyear annual average, Halton residents, 214. Note: Influenza numbers are provided for the Influenza Season of Sept. 1 st to Dec. 31 st of the previous year and Jan. 1 st to Aug. 31 st of the current report year. Source: Integrated Public Health Information System [29-214], extracted March 23, Halton Region Infectious Disease Report 7

14 Age-standardized incidence rate (per 1,) Influenza Of the 45 cases of potentially vaccine-preventable disease, 379 were residents of Halton diagnosed with influenza (during the Sept. 1, 213 to Aug. 31, 214 influenza season). Influenza is a highly infectious respiratory illness caused by one of the three types of influenza virus: A, B, or C (C is not common nor an important cause of illness, does not have a vaccine, and is not tested for by the laboratory). In contrast to the common cold, symptoms of influenza are more sudden in onset and more severe (fever, headache, muscle ache, and profound tiredness, followed by the onset of a dry cough), especially in very young, old, or immunecompromised persons. Many cases of influenza are not diagnosed or reported to the Halton Region Health Department because infected individuals often do not seek medical attention or, when doctors are visited, physicians often do not seek laboratory confirmation because it is unnecessary in uncomplicated situations when influenza is known to be circulating. Monitoring influenza is important due to how quickly epidemics evolve, the widespread morbidity, and the seriousness of complications, notably viral and bacterial pneumonias. Halton age-standardized influenza incidence rates have been similar to those of the province (Figure 3). The impact of influenza as well as the rate of clinical testing are highly variable and therefore annual fluctuations above or below the provincial average are not surprising. The number of laboratory-confirmed cases of influenza can be helpful for tracking the timing and severity of the influenza season. However the actual numbers are always an underestimate because a large proportion of infected persons would not receive laboratory testing Halton Year Ontario Figure 3: Influenza, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Notes: Influenza numbers are provided for the Influenza Season of Sept. 1 st to Dec. 31 st of the previous year and Jan. 1 st to Aug. 31 st of the current report year. Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ontario Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long- Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 8

15 Age-standardized incidence rate (per 1,) Streptococcus pneumoniae In 214, there were 41 reported cases of invasive Streptococcus pneumoniae, accounting for 9% of the reportable vaccine-preventable diseases. Pneumococcal disease is a major cause of pneumonia (not reportable) and meningitis (reportable) among children and the elderly. As seen in Figure 4, the age-standardized incidence rates of Streptococcus pneumoniae in Halton were quite variable in the past five years of reporting, as would be expected because of the relatively small numbers. In 214, the Halton age-standardized incidence rate for this infectious disease (6.2 per 1, population) was not statistically significantly different from the provincial rate (6.4 per 1, population) (Table 2) Halton Ontario Figure 4: Invasive Streptococcus pneumoniae, age-standardized incidence rates per 1, population, Halton residents Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 9

16 Chickenpox Chickenpox, or varicella, is an acute, generalized viral disease with sudden onset of slight fever, mild constitutional symptoms, and a skin eruption that is maculopapular for a few hours, followed by small blisters for 3 to 4 days, and then granular scab that may leave small scars. Chickenpox is transmitted person-to-person by direct contact, droplet, or airborne spread of vesicle fluid or secretions of the respiratory tract. It is one of the most readily communicable of diseases, especially in the early stages. Susceptible individuals have an 8% to 9% risk of infection after household exposure. This viral infection remains latent and the disease may recur years later as herpes zoster in about 15% of older adults, and sometimes in children. The one-dose varicella immunization program was introduced in Ontario in 24 and was added to the children s immunization schedule. The program was expanded in August 211 to include a second dose to reduce breakthrough infections from waning immunity in individuals who previously received a single dose. As of January 25, the first year for which case-specific data was available, individual laboratory-confirmed reports or those cases resulting in complications or hospitalization were reportable to the Health Department. However, cases that ran their course of illness at home may not have been reported to the Halton Region Health Department. Also, physicians may make a clinical diagnosis of the disease and may not report it to the health department. Therefore caution must be taken when interpreting local and provincial data as it is subject to significant underreporting. In 214, in Halton residents, there were 15 lab-confirmed cases of chickenpox. Six (4%) of these cases occurred in children aged to 14 and five (33%) in adults aged 4 to 49. Since lab-confirmed cases are so underreported, cases of varicella presenting to emergency departments between 24 and 214 were examined. This allows for an analysis of the trends as well as comparison between Halton and Ontario. 214 Halton Region Infectious Disease Report 1

17 Number of ED visits Age-standardized rate (per 1,) Chickenpox Emergency Department visits In Halton residents, between 24 and 214, the number of emergency department (ED) visits due to chickenpox declined by 64% from 129 visits in 24 to 47 visits in 214. The biggest decline in the number of ED visits occurred between 24 and 25 when the number of visits in Halton went from 129 to 89 (Figure 5). This may in part by explained by the introduction of the chickenpox vaccine in 24. In Halton, the age-standardized rate of emergency department visits attributed to chickenpox declined significantly from 33.7 per 1, in 24 to 9.7 per 1, in 214 (Figure 5) Year Halton ED visits Halton age-std rate per 1, Ontario age-std rate per 1, Figure 5: Chickenpox (varicella), total number of ED visits in Halton and age-standardized rates of emergency department visits, Halton residents compared to Ontario, Notes: Varicella emergency department visits may be used as a proxy to indicate the severity of the disease. Sources: National Ambulatory Care Reporting Centre, Ministry of Health and Long-Term Care, IntelliHEALTH Ontario, extracted [May 1, 215]. Population Estimates, Ministry of Health and Long-Term Care, IntelliHEALTH Ontario, extracted [March 21, 214]. In Ontario overall, the total number of ED visits due to chickenpox declined by 62% from 6,2 in 24 to 2,342 in 214 (not shown). The age-standardized rate of ED visits due to chicken pox in Ontario, during this time period, declined significantly from 58.7 per 1, population to 2.5 per 1, population (Figure 5). In 214, Halton s age-standardized rate of emergency department visits attributed to chickenpox was statistically significantly lower compared to Ontario s (SIR=.47 [95% CI:.34-.6]). In 214, children aged to 9 accounted for 6% of the total emergency department visits attributed to chickenpox in Halton and 55% in Ontario overall (Figure 6). 214 Halton Region Infectious Disease Report 11

18 % of ED visits Age Group Halton Ontario Figure 6: Proportion of emergency department visits attributed to chickenpox, by age group, Halton and Ontario, 214. Sources: National Ambulatory Care Reporting Centre, Ministry of Health and Long-Term Care, IntelliHEALTH Ontario, extracted [May 1, 215]. Population Estimates, Ministry of Health and Long-Term Care, IntelliHEALTH Ontario, extracted [March 21, 214]. 214 Halton Region Infectious Disease Report 12

19 Number of reported cases Food- and Water-borne Diseases Infectious diseases spread by food and water are caused by bacteria, parasites, and viruses that have found their way into the water supply or food source from an infected animal or person. Because the route of exposure to food- and water-borne diseases is by ingestion and because the symptoms are usually related to the digestive tract, these diseases are often also referred to as enteric diseases, meaning relating to the intestine. Many of these diseases are sometimes also transmitted from person to person, even when there is careful attention paid to personal hygiene. These diseases may cause nausea, vomiting, abdominal pain, diarrhoea, bloody stools, fever, and systemic illness that can be severe. Illness caused by toxins (e.g., from Staphylococcus aureus) or other toxic agents can also be spread by food and water. In 214, 377 Halton residents were diagnosed with a food- or water-borne disease, accounting for 18% of the total cases of reportable infectious diseases that year (Appendix B). Figure 7 shows the number of new cases of food- and water-borne diseases among Halton residents in 214 compared to the previous five-year annual average Disease Annual Average Figure 7: Most frequently reported food- and water-borne diseases compared to previous fiveyear annual average, Halton residents, 214. Source: Integrated Public Health Information System [29-214], extracted March 23, 215. In addition to the diseases highlighted in Figure 7, there were also a total of 43 cases of the following diseases, accounting for the remaining 11% of this disease category: hepatitis A, legionellosis, listeriosis, paratyphoid fever, shigellosis, typhoid fever, verotoxin-producing Escherichia coli, and yersiniosis. For these, the numbers have remained fairly stable when compared to the previous five-year average. Please refer to Appendix B for the number of reported cases in 214 for these remaining diseases. 214 Halton Region Infectious Disease Report 13

20 Age-standardized incidence rate (per 1,) Campylobacter enteritis Of the 377 cases of reported food- and water-borne infectious disease in Halton in 214, 128 (34%) were diagnosed with Campylobacter enteritis. There were 135 cases of Campylobacter enteritis reported on average per year in the previous five years (Figure 7). Animals most frequently poultry and cattle are the reservoirs of the causative organisms. The most common mode of transmission of this disease is through ingestion of the organisms in undercooked meat, contaminated food or water, or unpasteurized milk. Over the past 1 years, the age-standardized incidence rates in Halton followed similar incidence rates as Ontario (Figure 8). In 214, the Halton age-standardized incidence rate of campylobacteriosis (22.9 per 1, population) was similar to the Ontario age-standardized incidence rate (27.3 per 1, population) (Table 2) Year Halton Ontario Figure 8: Campylobacter enteritis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 14

21 Age-standardized incidence rate (per 1,) Giardiasis Giardiasis accounted for 12% of the food- and water-borne infections (46 cases) reported in Halton in 214. There were 51 cases of giardiasis reported on average per year in the previous five years (Figure 7). Giardiasis is a protozoan infection principally of the upper small intestine, which can a) remain asymptomatic; b) bring on acute, self-limited diarrhoea; or c) lead to intestinal symptoms such as chronic diarrhoea, abdominal cramps, bloating, frequent loose, pale, greasy stools, fatigue, malabsorption (of fats and fat-soluble vitamins), and weight loss. The reservoirs are humans, and possibly beaver and other wild and domestic animals. Person-to-person transmission occurs by hand-to-mouth transfer of cysts from the faeces of an infected individual, especially in institutions and day care centres; this is probably the principal mode of spread. The incubation period is usually between 3 and 25 days, with a median of 7 to 1 days. The period of communicability is during the entire period of infection, and often for months afterwards. In the past 1-year period, Halton s age-standardized rates of giardiasis have been similar to or lower than Ontario s rates (Figure 9). In 214, Halton s age-standardized rate of 8.2 cases per 1, population was similar to Ontario s age-standardized rate of 9.7 cases per 1, population (Table 2) Halton Year Ontario Figure 9: Giardiasis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 15

22 Age-standardized incidence rate (per 1,) Salmonellosis Salmonellosis accounted for 31% of the food- and water-borne infections (118 cases) reported in Halton in 214. There were 1 cases of salmonellosis reported on average per year in the previous five years (Figure 7). Salmonellosis is classified as a food-borne disease because contaminated food, mainly of animal origin, is the predominant mode of transmission. Over the past 1 years, the age-standardized incidence rates of salmonellosis in Halton fluctuated along with the Ontario rates (Figure 1). The high rate in Halton in 25 is attributed to a single outbreak in a food premises. In 214, the age-standardized incidence rate in Halton of 22.4 cases per 1, population was similar to the provincial rate (23.8 per 1, population) (Table 2) Year Halton Ontario Figure 1: Salmonellosis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 16

23 Number of reported cases Sexually-Transmitted Infections In 214, 1,6 Halton residents were diagnosed with a sexually-transmitted infection, accounting for 49% of the total cases of reportable infectious diseases (Appendix B). Figure 11 shows the number of new cases of sexually-transmitted infection among Halton residents in 214 compared to the previous five-year annual average Chlamydia Gonorrhea Syphilis - noninfectious HIV Syphilis - infectious AIDS Disease Annual Average Figure 11: Sexually-transmitted infections compared to previous five-year annual average, Halton residents, 214. Source: Integrated Public Health Information System [29-214], extracted March 23, Halton Region Infectious Disease Report 17

24 Chlamydia Of the 1,6 cases of reported sexually-transmitted infections in Halton in 214, 822 were diagnosed with chlamydia. These cases accounted for 82% of all the sexually-transmitted infections for Halton residents. There were 772 reported cases on average per year in the previous five years (Figure 11). Chlamydia is the most common bacterial sexually-transmitted infection. It manifests in men primarily as urethritis, and in females as cervical infection. However, up to 7% of sexually active females with chlamydia infections are asymptomatic. Complications of chlamydial infection include infertility and congenital infection. Asymptomatic infections can also be found in up to 25% of sexually active men. Therefore, this disease is likely to be under-reported. The age-standardized incidence rates of chlamydial infections in Halton showed a rising trend between 24 and 21 (Figure 12). These rates followed the general upward trend experienced in Ontario overall, with Halton s age-standardized incidence rates remaining significantly below the provincial rates. The increasing incidence of chlamydia has also been noted for Canada as well as Ontario. In Halton, the standardized incidence rate increased 62% between 25 and 214, from per 1, to 18.7 per 1, residents. Some of this increase is attributed to improved quality and acceptability of screening and testing methods. However, chlamydia is a hidden epidemic due to lack of awareness of the problem and because the majority of cases are asymptomatic but still infectious. Awareness-raising initiatives continue to be critical components of promotional strategies targeting the importance of safer sex practices especially the use of condoms and testing for sexually transmitted infections. Persons who became infected with chlamydia showed they were at risk for becoming infected with gonorrhoea, syphilis, or HIV, had any one of these sexually transmitted infections also been present in the sexual partner. Rising trends are reported for other sexually transmitted infections. Similar to Ontario, the majority of cases in Halton were in youth and young adults. More specifically, 56% of cases were in those aged 15 to 24 years, and 39% were in those aged 25 to 44 years. 214 Halton Region Infectious Disease Report 18

25 Age-standardized incidence rate (per 1,) Year Halton Ontario Figure 12: Chlamydia, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 19

26 Age-standardized incidence rate (per 1,) Gonorrhoea In 214, there were 129 cases of reported gonorrhoea infections in Halton, accounting for 13% of all sexually-transmitted infections. There were 66 reported cases on average per year in the previous five years (Figure 11). The age-standardized incidence rate of gonorrhea had been relatively stable between 26 and 213; however, both Halton and Ontario saw an increase in 214 (Figure 13), although, Halton s gonorrhea rates continue to be consistently lower than Ontario. Public Health Ontario has been monitoring this increase provincially and has reported that it is not fully understood and likely multifactorial (PHO Monthly Infectious Disease Report, February 215). In particular they are examining antibiotic sensitivity, adherence to treatment and testing guidelines, and have undertaken an evaluation of Ontario s provincial treatment guidelines. Gonorrhoea, or gonococcal infection, is a sexually-transmitted bacterial infection, which differs in males and females in course, severity, and ease of recognition. Worldwide, this infection affects both men and women, especially sexually active adolescents and younger adults. Untreated individuals may be infectious for months. As seen in Ontario, the majority of cases in Halton were in youth and young adults. More specifically, 33% of cases were in those aged 15 to 24 years, and 52% were aged 25 to 44 years Year Halton Ontario Figure 13: Gonorrhea, age-standardized incidence rates per 1, population, Halton residents compared to Ontario Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 2

27 Number of reported cases Syphilis In 214, there were 39 reported cases of syphilis (1 infectious and 29 non-infectious) in Halton residents, accounting for 4% of all sexually-transmitted infections. There were 41 reported cases on average per year in the previous five years (Figure 14). Syphilis is a complex, sexually-transmitted bacterial infection characterized clinically by a primary lesion a chancre (painless ulcer), secondary eruptions involving skin and mucous membranes that are very infectious, long periods of latency, and later involvement of skin, bone, viscera, the central nervous system, and cardiovascular system. All untreated cases will go on to a latent period of weeks to years, and one-third will then exhibit tertiary syphilis signs and symptoms. In the early years of latency, there may be recurrence of infectious lesions of the skin and mucous membranes. Syphilis is infectious mostly during the acute phases, and is noninfectious during most of the latent period. Fetal infection results in congenital syphilis and occurs with high frequency in untreated early infections of pregnant women. Figure 14 shows the number of reported cases of syphilis, by type, among Halton residents in 214 compared to the previous five-year annual averages Syphilis - total Syphilis - infectious Syphilis - non-infectious Disease Annual Average Figure 14: Number of cases of syphilis compared to previous five-year annual average, Halton residents, 214. Source: Integrated Public Health Information System [29-214], extracted March 23, Halton Region Infectious Disease Report 21

28 Age-standardized incidence rate (per 1,) Halton s age-standardized incidence rates of infectious syphilis fluctuated but showed a general increase over the 1-year period (Figure 15). The 214 age-standardized incidence rate was 2. cases per 1,. These fluctuations are due to the small number of reported cases on a year-to-year basis. In Ontario, infectious syphilis has been increasing from a rate of 2.9 cases per 1, population in 25 to a rate of 6.3 cases per 1, in 214 (Figure 15). Between 25 and 214, the age-standardized incidence rate of non-infectious syphilis in Ontario was on average 6.9 cases per 1, population. Newly diagnosed non-infectious syphilis cases are found primarily through screening and the higher rates of non-infectious disease may reflect increased screening. While cases of noninfectious syphilis may have actually been acquired years before they are diagnosed and reported, they are still counted as incident cases in the year of diagnosis Year Halton Syphilis - Infectious Ontario Syphilis - Infectious Halton Syphilis - Non-infectious Ontario Syphilis - Non-infectious Figure 15: Infectious and non-infectious syphilis, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Note: Ontario data for non-infectious syphilis prior to 25 is not available. Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 22

29 Number of reported cases Select Blood-borne Infections Blood-borne infections are those which can be transmitted by direct contact with blood or bodyfluids, or by organ transplants involving infected organs, and also include some diseases which are transmitted by unprotected sex or injection drug use. In the past these infections were also spread by blood transfusions; now blood donor screening prevents almost all such cases in which the agent is known and for which a test is available and being used. All reportable blood-borne infections can lead to a state where the body becomes permanently or persistently infected, and the micro-organism can be found in the blood and other body fluids over long periods of time. Understanding the epidemiology of blood-borne infections is particularly important for those infections that can be prevented by vaccination. A goal of the World Health Organization is to have all children vaccinated to prevent hepatitis B infection. This would ultimately eliminate the infection. In Ontario, hepatitis B vaccine has been routine for 12-year-olds since It is also provided to infants born to infected mothers and to other high risk groups. In 214, 143 Halton residents were diagnosed with a reportable blood-borne infection, accounting for 7% of the total cases of reportable infectious diseases/infections that year (Appendix B). Figure 16 shows the number of new cases of selected blood-borne infections among Halton residents in 214 compared to the previous five-year annual averages Hepatitis C Hepatitis B - carriers Hepatitis B - cases Disease Annual Average Figure 16: The number of selected blood-borne infections compared to previous five-year annual average, Halton residents, 214. Source: Integrated Public Health Information System [29-214], extracted March 23, Halton Region Infectious Disease Report 23

30 Age-standardized incidence rate (per 1,) Hepatitis C In 214, there were 12 reported cases of hepatitis C virus (HCV) infection among Halton residents. This accounts for 71% of the blood-borne infections presented in this report. On average, there were 97 reported cases of HCV per year in the previous five years (Figure 16). Hepatitis C is a blood-borne disease, primarily transmitted directly into the bloodstream by contaminated injection equipment or products. HCV is directly related to the prevalence of persons who routinely share injection equipment and to the prevalence of poor blood-borne infection control procedures and practices in health care settings (the latter being more applicable to developing countries). The World Health Organization estimates that some 13 to 17 million people (approximately 2% to 3% of the world population) are chronically infected with HCV, which, like hepatitis B virus, is one of the most common global causes of chronic hepatitis, cirrhosis, and liver cancer. Since 25, other than the small increase in 27, both Ontario s and Halton s hepatitis C incidence rates have generally been declining (Figure 17). In 214, Halton s age-standardized incidence rate for hepatitis C of 19.5 cases per 1, population was significantly lower than Ontario s age-standardized incidence rate of 3. per 1, population Year Halton Ontario Figure 17: Hepatitis C, age-standardized incidence rates per 1, population, Halton residents compared to Ontario, Sources: Reportable Disease Information System [24-25], extracted May 15, 27; Integrated Public Health Information System [25-214], extracted March 23, 215; Population Estimates, IntelliHealth, Ministry of Health and Long-Term Care [215], extracted March 21, 215. Ontario data: Ontario Ministry of Health and Long-Term Care, Integrated Public Health System database, extracted by Public Health Ontario [March 3, 215]. 214 Halton Region Infectious Disease Report 24