Canada communicable disease report = Releve des maladies transmissibles au Canada最新文献

Background: This article continues the annual series on tick surveillance in Canada, tracking two of the primary tick vectors of concern in the country, Ixodes scapularis and Ixodes pacificus, which can transmit the agent of Lyme disease alongside several other tick-borne pathogens.

Objective: This study analyzed passive and active tick surveillance data, including geographic distribution, pathogen prevalence and other characteristics to inform public health prevention.

Methods: Passive and active surveillance data were compiled from eTick (an online, image-based platform), the National Microbiology Laboratory (Public Health Agency of Canada), provincial and local public health authorities and the Canadian Lyme Disease Research Network. Descriptive statistics of ticks and their associated pathogens are presented, including infection prevalence estimates.

Results: In 2022, a total of 7,030 I. scapularis were submitted through passive surveillance from all provinces, while 911 I. pacificus were submitted from British Columbia (n=909) and Yukon (n=2). Ixodes scapularis submissions peaked in May and again in October. For I. pacificus, submissions peaked in May with a second, smaller peak in November. Six tick-borne pathogens (Anaplasma phagocytophilum, Borrelia burgdorferi, Borrelia miyamotoi, Babesia microti, Babesia odocoilei, Powassan virus) were identified from the I. scapularis collected by dragging in Manitoba, Ontario, Québec, New Brunswick or Nova Scotia.

Conclusion: This report provides a summary of tick surveillance data collected in 2022. Tick characteristics and tick-borne pathogen infection prevalence were similar to previous years. Tick surveillance continues to play an important role in monitoring infection prevalence among ticks and their geographic distribution, which will help inform public health prevention and intervention efforts.

This rapid communication describes a case of cutaneous lesions in a donkey in Ontario, Canada, from which toxigenic Corynebacterium diphtheriae (C. diphtheriae) was isolated. Seven human close contacts were identified and assessed. This communication focuses on public health challenges, interagency response and implications for One Health initiatives to prevent zoonotic transmission. Furthermore, it underscores the importance, successes and challenges of interagency collaboration to coordinate timely laboratory investigation, reporting, contact tracing, potential post-exposure prophylaxis and public education in responding to zoonotic disease. This investigation demonstrates the need for enhanced surveillance, clear legislative authority to facilitate reporting, and more specific guidance for close contact management of C. diphtheriae and other zoonotic agents in animals, which can cause morbidity and mortality in humans.

Background: Herpes zoster (HZ), or shingles, results from the reactivation of latent varicella-zoster virus and poses a significant health burden and immunocompromised adults are at higher risk of HZ and its complications. In 2018, the recombinant zoster vaccine (RZV, Shingrix®) was strongly recommended by the National Advisory Committee on Immunization (NACI) for immunocompetent adults aged 50 years and older. Since then, evidence has accumulated on the use of RZV in immunocompromised adults and in 2021, Health Canada expanded the authorization of RZV to adults 18 years of age and older who are or will be immunocompromised.

Methods: NACI assessed the burden of HZ in immunocompromised populations, reviewed evidence on the efficacy, effectiveness, immunogenicity and safety of RZV, and published economic evaluations. Programmatic considerations were evaluated using NACI's ethics, equity, feasibility and acceptability framework. The evidence and programmatic considerations were organized using a process informed by the Grading of Recommendations, Assessment, Development and Evaluation framework, and this information was then used to facilitate NACI guidance development.

Results: The risk of HZ among younger adults who are immunocompromised is comparable to or higher than the general population of 50 years of age and older. High efficacy and robust immune responses after RZV administration was demonstrated in groups with various types of immunocompromising therapies and conditions, with an acceptable safety profile. Economic evaluations showed that RZV was cost-effective in some high-risk immunocompromised groups. Expanding access to RZV may reduce disease burden and address inequities in vaccine access.

Conclusion: NACI updated its guidance to strongly recommend that individuals 18 years of age and older who are or will be immunocompromised should receive two doses of RZV to prevent HZ and its associated complications.

Background: Ixodes scapularis and Ixodes pacificus ticks pose risk of infection with tick-borne diseases in Eastern and Pacific Western Canada, respectively.

Objective: In 2021, passive and active tick surveillance programs collected ticks and associated data elements, including location, infection and other characteristics, to monitor their populations and inform public health prevention and mitigation activities.

Methods: Surveillance data for ticks were compiled from the National Microbiology Laboratory (Public Health Agency of Canada), provincial public health, Canadian Lyme Disease Research Network and eTick (an image-based online platform). A descriptive analysis of tick records and infection prevalence of tick-borne pathogens is presented. Seasonal trends are described.

Results: During 2021, 6,892 I. scapularis ticks were identified across all ten provinces via passive surveillance with 777 I. pacificus ticks collected from British Columbia. Most were adult female ticks, collected from human hosts in the spring (March-May) or fall (October-November) seasons. The most common pathogen, Borrelia burgdorferi, was detected in 18.6% (95% CI: 17.2%-20.1%) of samples. Active surveillance resulted in 1,929 I. scapularis and 18 I. pacificus ticks collected in six provinces. Among I. scapularis, 22.3% were infected with B. burgdorferi, 11.8% with Babesia odocoilei and 4.3% with Anaplasma phagocytophilum. Fewer than 1% were infected with each of Borrelia miyamotoi (0.7%), Babesia microti (0.1%) and Powassan virus (0.1%).

Conclusion: As the risk of infection with tick-borne diseases continues to grow in many parts of Canada, monitoring trends in infection prevalence and the geographical range expansion of ticks provides essential data to inform public health actions and messaging.

Background: This case report describes a young male with multidrug-resistant Neisseria gonorrhoeae infection acquired in Ontario, Canada with no travel history.

Methods: Case follow-up was conducted following routine public health practice in Ontario. Antimicrobial susceptibility testing of the isolate was done by agar dilution. Strain typing and other molecular characterization was done by whole genome sequencing.

Results: The patient was treated successfully with intramuscular ceftriaxone and oral azithromycin. Agar dilution testing demonstrated reduced susceptibility to all tested agents, except for azithromycin and spectinomycin, including non-susceptibility to ceftriaxone (minimum inhibitory concentration [MIC]=0.5 mg/L) and cefixime (MIC=2 mg/L), resistance to tetracycline (MIC=2 mg/mL) and ciprofloxacin (MIC=32 mg/L), and testing intermediate to penicillin (MIC=1 mg/L). Whole-genome sequencing revealed the isolate was closely related to the FC428 clone, which harbours the mosaic penA60 allele responsible for elevated MICs to extended-spectrum cephalosporins, such as ceftriaxone or cefixime, both currently recommended as first-line or alternative treatment options for uncomplicated anogenital gonorrhea infections in Ontario.

Conclusion: Identification of this case suggests previously unrecognized local transmission of this multidrug-resistant N. gonorrhoeae strain is occurring in Ontario and highlights the need for ongoing surveillance to monitor trends and inform treatment recommendations.

Background: The domestic tuberculosis (TB) disease burden in high-income, low TB-incidence countries is largely driven by the reactivation of remotely acquired TB infections (TBIs) in people born outside the country (PBOC). In Canada, PBOC now accounts for more than three quarters of annual active TB diagnoses. To prevent some of this disease experience, Immigration, Refugees and Citizenship Canada (IRCC) rolled out a new TBI screening initiative in 2019.

Objective: An evaluation of TB outcomes among individuals referred through this initiative between May 2019 and May 2023 in Alberta, Canada.

Methods: Inclusion criteria for this initiative are migrants who are required to undergo an immigration medical exam with at least one of HIV/AIDS, solid organ transplant, end-stage renal disease, recent close TB contact (within five years), and past head and neck cancer. Those with a positive screening test for TBI are referred directly to TB services in the stated province/territory of landing for assessment and treatment.

Results: Over four years, 179 referrals were made to Alberta. No one referred through the program and offered treatment developed active TB. Overall, 95 individuals were considered suitable candidates for prevention, among whom 87% accepted. Completion was high at nearly 95%. Inefficiencies included 113 individuals undergoing repeated TBI testing locally, 39 (21.8%) referrals not meeting the inclusion criteria, and 61 (34.1%) individuals being rereferred despite being past patients of Alberta TB services.

Conclusion: Our findings highlight that, in Alberta, IRCC's new TBI screening initiative was highly successful in connecting referred individuals to TB services. The initiative experienced some inefficiencies and we describe areas where it could be improved.

Background: Public health models often lack comprehensive behavioural data, leading to inaccurate predictions about the spread of disease and insufficient information about how to effectively build and sustain adherence to changing public health protocols.

Objective: The current study addresses this lack of comprehensive behavioural data by examining the role of trust as a predictor of adherence to public health measures.

Methods: Data were collected from an online Web intercept survey of 3,021 randomly engaged Canadians aged 16 years and older, analyzing factors such as gender, education and sources of COVID-19 information in relation to adherence to public health guidelines.

Results: Trust, respecting someone's expertise sufficiently to be willing to accept their counsel, emerged as a potent predictor of adherence to public health measures, highlighting the significance of trust in shaping community engagement; further, community-level adherence was found to predict anticipated future adherence.

Conclusion: This study emphasizes the critical role of trust, especially at the community level, in the success of public health measures, and proposes integrating trust measurement into public health models of compliance and resistance.

Background: Treating individuals with tuberculosis (TB) infection (TBI) is an important aspect of the global strategy to eliminate TB as a public health problem, as it would help reduce the pool of individuals with TBI who are at risk of developing TB disease (TBD). Understanding factors that impact effective management of patients with TBI is helpful in informing policy.

Objective: To assess the proportion of immigrants with TBI accepting and completing TB preventive treatment (TPT), variables potentially related to accepting and completing TPT were examined and healthcare provider (HCP)-related factors that impact TBI management were identified.

Methods: Tuberculosis preventive treatment was offered to TBI-positive immigrants without a history or treatment of TBD from a pilot TBI screening study conducted in southern New Brunswick, Canada between November 2021 and November 2023. Tuberculosis preventive treatment acceptance and completion rates were calculated, and the HCP completed a questionnaire to identify factors that affected TBI management. Participant characteristics were summarized using descriptive statistics, while Fisher's exact tests were conducted to test for independence between demographics and treatment acceptance and completion. The HCP questionnaire data were analyzed using thematic analysis.

Results: Of the 49 participants who screened positive for TBI, 11 (22.4%) were lost to follow-up prior to being assessed and offered TPT and 38 (77.6%) were offered TPT, of whom 3 (7.9%) declined, 35 (92.1%) accepted and initiated TPT, and 30 (85.7%) completed treatment. Treatment acceptance and completion were found to be independent from the participant demographics examined. Thematic analysis revealed five emerging themes regarding the management of TBI participants (i.e., supports, collaboration, communication, time, and satisfaction).

Conclusion: This study demonstrates the feasibility of treating TBI in immigrants and highlights HCP-related factors that impact the management of TBI among immigrants in southern New Brunswick. Our findings may assist programs aimed at improving TBI screening and treatment.

Background: Exposure incidents to human pathogens and toxins (HPTs) in licensed facilities in Canada are monitored by Laboratory Incident Notification Canada (LINC), a surveillance system that describes and identifies trends among exposure incidents in Canada using quantitative and qualitative data.

Methods: Confirmed exposure incidents reported to LINC in 2024 were analyzed. The exposure incident rate was calculated and compared to previous years. A seasonality analysis compared monthly trends. Exposure incidents were described by sector, implicated HPTs, main activity, occurrence types, root causes, affected individuals and reporting delay. Text-based descriptions of exposure incidents underwent qualitative analysis.

Results: In 2024, there were 71 confirmed exposure incidents affecting 132 individuals. There were 67.5 incidents per 1,000 active licences. Bacteria was the most commonly implicated HPT (64%). Microbiology (67.6%) was the primary activity during confirmed exposures. The public health sector had the highest incident rate and mean number of affected persons per active licence. The most frequently reported occurrence type and root cause was procedure-related (21.4%) and human factors (62%), respectively. Most affected individuals were technicians/technologists (76.5%). The median time between incident and reporting was five days.

Conclusion: The exposure incident rate was higher in 2024 compared to the previous year. The public health sector had the highest incident rate between 2016-2024. Qualitative analysis revealed that working with cultures outside the biological safety cabinet and insufficient face-related personal protective equipment were common factors involved in confirmed exposure incidents.

Background: Pneumococcal disease in adults includes invasive pneumococcal disease (IPD), an acute and serious communicable disease with manifestations such as meningitis, bacteremia and bacteremic pneumococcal pneumonia. There are more than 100 different serotypes, and the extent of protection provided by a pneumococcal vaccine depends on the vaccine formulation. In July 2024, Health Canada authorized a 21-valent pneumococcal conjugate vaccine (Pneu-C-21), which followed the recent introduction of a 20-valent vaccine (Pneu-C-20) authorized in 2022.

Methods: The National Advisory Committee on Immunization (NACI) reviewed evidence on the epidemiology of IPD in Canada, immunogenicity and safety of Pneu-C-21, and the cost-effectiveness of different pneumococcal vaccines in adult immunization programs. NACI has also considered additional factors, including ethics, equity, feasibility, and acceptability (EEFA).

Results: Differences in the distribution of serotypes causing IPD have been observed before and after the COVID-19 pandemic. The Pneu-C-21 demonstrated comparable immunogenicity to Pneu-C-20 for shared serotypes and higher responses for unique serotypes. The safety profiles of both vaccines are expected to be similar to other pneumococcal vaccines, and the cost-effectiveness of Pneu-C-21 and Pneu-C-20 will depend on regional serotype distribution. The overall impact of Pneu-C-21 compared to Pneu-C-20 is uncertain, but likely to vary over time with age, risk factors, and geography.

Conclusion: NACI now recommends including at least one of Pneu-C-20 or Pneu-C-21 in adult pneumococcal immunization programs. One dose should be given to adults 65 years and older and those 18 to under 65 years at increased IPD risk, regardless of previous pneumococcal vaccination history.