Measles Outbreak with Unique Virus Genotyping, Ontario, Canada, 2015.
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ABSTRACT:
SUBMITTER: Thomas S
PROVIDER: S-EPMC5512469 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundGiven that measles is eliminated in Canada and measles immunisation coverage in Ontario is high, it has been questioned whether Ontario's measles outbreak response is worthwhile.AimOur objective was to determine cost-effectiveness of measles containment protocols in Ontario from the healthcare payer perspective.MethodsWe developed a decision-analysis model comparing Ontario's measles containment strategy (based on actual 2015 outbreak data) with a hypothetical 'modified response'. The modified scenario assumed 10% response costs with reduced case and contact tracing and no outbreak-associated vaccinations; it was based on local and provincial administrative and laboratory data and parameters from peer-reviewed literature. Short- and long-term health outcomes, quality-adjusted life years (QALYs) and costs discounted at 1.5%, were estimated. We conducted one- and two-way sensitivity analyses.ResultsThe 2015 outbreak in Ontario comprised 16 measles cases and an estimated 3,369 contacts. Predictive modelling suggested that the outbreak response prevented 16 outbreak-associated cases at a cost of CAD 1,213,491 (EUR 861,579). The incremental cost-effectiveness ratio was CAD 739,063 (EUR 524,735) per QALY gained for the outbreak response vs modified response. To meet the commonly accepted cost-effectiveness threshold of CAD 50,000 (EUR 35,500) per QALY gained, the outbreak response would have to prevent 94 measles cases. In sensitivity analyses, the findings were robust.ConclusionsOntario's measles outbreak response exceeds generally accepted cost-effectiveness thresholds and may not be the most efficient use of public health resources from a healthcare payer perspective. These findings should be balanced against benefits of increased vaccine coverage and maintaining elimination status.
| S-EPMC6425553 | biostudies-literature
Project description:Background:Measles has been eliminated in Canada since 1998. Every year, the Public Health Agency of Canada presents epidemiologic evidence to the Pan American Health Organization (PAHO) to verify that measles elimination continues in Canada. Objective:To describe measles activity in Canada for 2015 as updated evidence for continued measles elimination status. Methods:Measles surveillance data were captured by the Canadian Measles and Rubella Surveillance System (CMRSS) and the Measles and Rubella Surveillance (MARS) pilot project and assessed for distribution by demographics and risk factors. Outbreak characteristics were summarized and genotypic and phylogenetic analyses were conducted and described. Surveillance data for 2015 were evaluated against PAHO's essential criteria for measles elimination status. Results:In 2015, the incidence of measles in Canada was 5.5 cases per 1,000,000 population, with 196 cases across four provinces. The majority of cases (87.2%, n=171) were not immunized and both age-specific incidence rates and case counts were highest among those aged 10 to 14 years (29.5 cases per 1,000,000 population, n=55). This was due in large part to a sizeable outbreak in a non-immunizing religious community. Overall, 10.7% (n=21) of cases were hospitalized. Genotype information was available for 100% of measles events (4/4 outbreaks and 6/6 sporadic cases). Canada met or partially met most of PAHO's criteria for verification of measles elimination. Conclusion:Although importations and areas of low immunization coverage continue to challenge Canada's elimination status, surveillance data for 2015 provides strong evidence that measles elimination has been maintained.
| S-EPMC5757721 | biostudies-literature
Project description:Real-time PCR has been developed to genotype measles virus (MV) isolates. MV strains circulating in epidemics in Gabon in 1984, Cameroon in 2001, Morocco in 2003, and France in 2004 were investigated. We developed a real-time amplification refractory mutation system PCR (RT-AMRS PCR) using SYBR green fluorescent dye. Six pairs of primers for RT-ARMS PCR were designed to specifically amplify genotypes A, B2, B3.1, B3.2, C2, and D7. Genotypes could be differentiated by melting curve analysis. All strains were also confirmed by direct sequencing. Using the result obtained by direct sequencing and phylogenetic analysis as the reference, the accuracy of MV by RT-ARMS PCR and melting curve analysis was 97%. However, the latter method is more rapid and sensitive than the former method. This method could be a useful tool for molecular epidemiological studies of MV, providing an efficient alternative for large-scale studies.
| S-EPMC1392642 | biostudies-literature
Project description:BACKGROUND:Surveillance data from a large measles outbreak in Mongolia suggested increased case fatality ratio (CFR) in the second of 2 waves. To confirm the increase in CFR and identify risk factors for measles death, we enhanced mortality ascertainment and conducted a case-control study among infants hospitalized for measles. METHODS:We linked national vital records with surveillance data of clinically or laboratory-confirmed infant (aged <12 months) measles cases with rash onset during March-September 2015 (wave 1) and October 2015-June 2016 (wave 2). We abstracted medical charts of 95 fatal cases and 273 nonfatal cases hospitalized for measles, matched by age and sex. We calculated adjusted matched odds ratios (amORs) and 95% confidence intervals (CIs) for risk factors. RESULTS:Infant measles deaths increased from 3 among 2224 cases (CFR: 0.13%) in wave 1 to 113 among 4884 cases (CFR: 2.31%) in wave 2 (P < .001). Inpatient admission, 7-21 days before measles rash onset, for pneumonia or influenza (amOR: 4.5; CI, 2.6-8.0), but not other diagnoses, was significantly associated with death. DISCUSSION:Measles infection among children hospitalized with respiratory infections likely increased deaths due to measles during wave 2. Preventing measles virus nosocomial transmission likely decreases measles mortality.
| S-EPMC7034305 | biostudies-literature
Project description:BackgroundHIV-positive individuals may acquire HCV via injection drug use (IDU) and condomless anal sex. HIV care provides opportunities for HCV testing and cure with direct-acting antiviral agents (DAAs).MethodsWe analyzed data from the Ontario HIV Treatment Network Cohort Study. Among those not HCV-positive or diagnosed previously (n = 4586), we used Cox regression to test the rates of ever HCV testing (serological or RNA) in HIV care by DAA era (pre-DAA: 2000-2010; after DAA: 2011-2015) and compared the proportion diagnosed with HCV. We identified correlates of annual proportions of serological testing using Poisson generalized estimating equations.ResultsAfter DAA vs pre-DAA, the hazard rate ratio (95% CI) of ever HCV testing was 1.70 (1.59, 1.81). The proportion (95% CI) tested annually increased from 9.2% (8.0%, 10.7%) in 2000 to 39.1% (37.1%, 41.1%) in 2015 (P < 0.0001). The proportion diagnosed with HCV declined by 74% pre-DAA to 11% after DAAs. Annual testing increased per calendar year (16% steeper slope after DAA vs pre-DAA) and was more common among men who have sex with men; those more educated (post-secondary vs ≤ high school); and those positive for syphilis or reporting any IDU. Annual testing decreased per decade of age and time since HIV diagnosis.DiscussionAnnual HCV testing increased over time with higher testing among those reporting sexual or IDU risk factors, but fell short of clinical guidelines. Targeted interventions to boost testing may be needed to close these gaps and reach WHO 2030 HCV elimination targets.
| S-EPMC8449285 | biostudies-literature
Project description:An outbreak of Legionnaires' disease at a long-term care facility in Ontario, Canada from September to October 2005 resulted in the death of 23 residents and the illness of 112 other people. In response, molecular methods were developed to detect Legionella pneumophila in clinical lung samples and to subtype isolates from clinical and environmental samples. The targeted genetic loci included Legionella-specific virulence determinants (mip, icmO, sidA and lidA) and core bacterial determinants (ftsZ, trpS and dnaX). An established amplified fragment length polymorphism typing method provided the first indication of genetic relatedness between strains recovered from clinical samples and strains cultured from environmental samples taken from the outbreak site. These associations were verified using the European Working Group for Legionella Infections sequence-based typing protocol targeting the flaA, pilE, asd, mip, mompS and proA loci. These molecular typing methods confirmed the outbreak source as a contaminated air conditioning cooling tower.
| S-EPMC2884934 | biostudies-literature
Project description:BackgroundIn 2015, a large nationwide measles outbreak occurred in Mongolia, with very high incidence in the capital city of Ulaanbaatar and among young adults.MethodsWe conducted an outbreak investigation including a matched case-control study of risk factors for laboratory-confirmed measles among young adults living in Ulaanbaatar. Young adults with laboratory-confirmed measles, living in the capital city of Ulaanbaatar, were matched with 2-3 neighborhood controls. Conditional logistic regression was used to estimate adjusted matched odds ratios (aMORs) for risk factors, with 95% confidence intervals.ResultsDuring March 1-September 30, 2015, 20 077 suspected measles cases were reported; 14 010 cases were confirmed. Independent risk factors for measles included being unvaccinated (adjusted matched odds ratio [aMOR] 2.0, P < .01), being a high school graduate without college education (aMOR 2.6, P < .01), remaining in Ulaanbaatar during the outbreak (aMOR 2.5, P < .01), exposure to an inpatient healthcare facility (aMOR 4.5 P < .01), and being born outside of Ulaanbaatar (aMOR 1.8, P = .02).ConclusionsThis large, nationwide outbreak shortly after verification of elimination had high incidence among young adults, particularly those born outside the national capital. In addition, findings indicated that nosocomial transmission within health facilities helped amplify the outbreak.
| S-EPMC10291145 | biostudies-literature
Project description:In February 2021, a cluster of Beta variant (B.1.351) coronavirus disease 2019 (COVID-19) cases were identified in an apartment building located in Northern Ontario, Canada. Most cases had no known contact with each other. Objectives of this multi-component outbreak investigation were to better understand the social and environmental factors that facilitated the transmission of COVID-19 through this multi-unit residential building (MURB). A case-control study examined building-specific exposures and resident behaviours that may have increased the odds of being a case. A professional engineer assessed the building's heating, ventilation, and air-conditioning (HVAC) systems. Whole-genome sequencing and an in-depth genomic analysis were performed. Forty-five outbreak-confirmed cases were identified. From the case-control study, being on the upper floors (OR: 10.4; 95% CI: 1.63-66.9) and within three adjacent vertical lines (OR: 28.3; 3.57-225) were both significantly associated with being a case of COVID-19, after adjusting for age. There were no significant differences in reported behaviours, use of shared spaces, or precautions taken between cases and controls. An assessment of the building's ventilation found uncontrolled air leakage between apartment units. A single genomic cluster was identified, where most sequences were identical to one another. Findings from the multiple components of this investigation are suggestive of aerosol transmission between units.
| S-EPMC11022249 | biostudies-literature
Project description:BackgroundIn September 2009, a mumps outbreak originated in New York and spread to Northeastern USA and Canada. This study compares the performance of different diagnostic testing methods used in Ontario and describes molecular characteristics of the outbreak strain.MethodsBetween September 2009 and February 2010, specimens from suspect cases were submitted to Public Health Ontario Laboratory for mumps serology, culture and/or real-time reverse-transcriptase PCR (rRT-PCR) testing. rRT-PCR-positive specimens underwent genotyping at Canada's National Microbiology Laboratory. Whole genome sequencing was performed on four outbreak and three sporadic viral culture isolates.ResultsSix hundred ninety-eight patients had IgM serology testing, of which 255 (37%) had culture and rRT-PCR. Among those, 35/698 (5%) were IgM positive, 39/255 (15%) culture positive and 47/255 (18%) rRT-PCR-positive. Buccal swabs had the highest rRT-PCR positivity (21%). The outbreak isolates were identical to that in the New York outbreak occurring at the same time. Nucleotide and amino acid identity with the Jeryl Lynn vaccine strain ranged from 85.0-94.5% and 82.4-99.4%, depending on the gene and coding sequences. Homology of the HN protein, the main immunogenic mumps virus protein, was found to be 94.5 and 95.3%, when compared to Jeryl Lynn vaccine major and minor components, respectively.ConclusionsDespite higher sensitivity than serology, rRT-PCR testing is underutilized. Further work is needed to better understand the suboptimal match of the HN gene between the outbreak strain and the Jeryl Lynn vaccine strain.
| S-EPMC5987625 | biostudies-literature
Project description:To determine the origin of the virus associated with a measles outbreak in Menglian County, Yunnan Province, People's Republic of China, in 2009, we conducted genetic analyses. Phylogenetic analyses based on nucleoprotein (N) and hemagglutinin (H) gene sequences showed that these Menglian viruses were not closely related to sequences of any World Health Organization (WHO) reference strains representing the 23 currently recognized genotypes. The minimum nucleotide divergence between the Menglian viruses and the most closely related reference strain, genotype D7, was 3.3% for the N gene and 3.0% for the H gene. A search of the databases of GenBank, WHO, and the Health Protection Agency Measles Nucleotide Surveillance showed that the Menglian viruses, together with the 2 older non-Menglian viruses, could be members of a new proposed measles genotype, d11. The new genotype designation will allow for better description of measles transmission patterns, especially in the Southeast Asian and Western Pacific regions.
| S-EPMC3086224 | biostudies-literature