The continued rise of Lyme disease in Ontario, Canada: 2017.

BACKGROUND: Lyme disease is an infection caused by the spirochete Borrelia burgdorferi and, in most of North America, is transmitted by the blacklegged tick Ixodes scapularis. Climate change has contributed to the expansion of the geographic range of blacklegged ticks in Ontario, increasing the risk of Lyme disease for Ontarians. OBJECTIVE: To identify the number of cases and incidence rates, as well as the geographic, seasonal and demographic distribution of Lyme disease cases reported in Ontario in 2017, with comparisons to historical trends. METHODS: Data for confirmed and probable Lyme disease cases with episode dates from January 1, 2012, through December 31, 2017, were extracted from the integrated Public Health Information System (iPHIS). Data included public health unit (PHU) of residence, episode date, age and sex. Population data from Statistics Canada were used to calculate provincial and PHU-specific incidence rates per 100,000 population. The number of cases reported in 2017 by PHU of residence, month of occurrence, age and sex was compared to the 5-year averages for the period 2012-2016. RESULTS: There were 959 probable and confirmed cases of Lyme disease reported in Ontario in 2017. This was three times higher than the 5-year (2012-2016) average of 313. The provincial incidence rate for 2017 was 6.7 cases per 100,000 population, although this varied markedly by PHU. The highest incidence rates were found in Leeds-Grenville and Lanark District (128.8 cases per 100,000), Kingston-Frontenac, Lennox and Addington (87.2 cases per 100,000), Hastings and Prince Edward Counties (28.6 cases per 100,000), Ottawa (18.1 cases per 100,000) and Eastern Ontario (13.5 cases per 100,000). Cases occurred mostly from June through September, were most common among males, and those aged 5-14 and 50-69 years. CONCLUSION: In 2017, Lyme disease incidence showed a marked increase in Ontario, especially in the eastern part of the province. If current weather and climate trends continue, blacklegged ticks carrying tick-borne pathogens, such as those causing Lyme disease, will continue to spread into suitable habitat. Monitoring the extent of this geographic spread will inform future clinical and public health actions to detect and mitigate the impact of Lyme disease in Ontario.

Invasive serogroup W Neisseria meningitidis (MenW) in Ontario, Canada shows potential clonal replacement during the period January 1, 2009 to June 30, 2016.

BACKGROUND: In Ontario, serogroup W Neisseria meningitidis (MenW) accounts for a small percentage of all invasive meningococcal disease (IMD) and between 2010 and 2014, only zero to three confirmed cases occurred per year. However, between August 2015 and June 2016, six culture confirmed MenW IMD cases were reported in Ontario. OBJECTIVE: All MenW IMD cases in Ontario between January 1, 2009 and June 30, 2016 were reviewed and the N. meningitidis strains involved were characterized. METHODS: MenW cases were identified in the Integrated Public Health Information System byf Public Health Ontario. MenW isolates were characterized at the National Microbiology Laboratory. RESULTS: Of the thirteen MenW IMD cases, six were due to isolates typed as sequence type (ST)-22 clonal complex (cc), six were of ST-11 cc, and one ST-167 cc. Most (83%) MenW cases due to the ST-22 cc occurred prior to 2012 while all six MenW cases due to ST-11 cc happened since May 2014. The six MenW ST-11 isolates appeared to be clonal. CONCLUSION: It appears that a genetic shift in the invasive MenW isolates has occurred in Ontario in 2014 with the ST-11 clone replacing the traditional ST-22 clone.

Optimal number of samples to test for institutional respiratory infection outbreaks in Ontario.

The objective of this study was to determine the optimal number of respiratory samples per outbreak to be tested for institutional respiratory outbreaks in Ontario. We reviewed respiratory samples tested for respiratory viruses by multiplex PCR as part of outbreak investigations. We documented outbreaks that were positive for any respiratory viruses and for influenza alone. At least one virus was detected in 1454 (85∙2%) outbreaks. The ability to detect influenza or any respiratory virus increased as the number of samples tested increased. When analysed by chronological order of when samples were received at the laboratory, percent positivity of outbreaks testing positive for any respiratory virus including influenza increased with the number of samples tested up to the ninth sample, with minimal benefit beyond the fourth sample tested. Testing up to four respiratory samples per outbreak was sufficient to detect viral organisms and resulted in significant savings for outbreak investigations.