Infection In Canada Research Articles

Lyme disease in Canada: Focus on children

Lyme disease, the most common tick-borne infection in Canada and much of the United States, is caused by the bacteria Borrelia burgdorferi. Peak incidence for Lyme disease is among children five to nine years of age and older adults (55 to 59 years of age). The bacteria are transmitted through the bite of infected black-legged ticks of the Ixodes species. The primary hosts of black-legged ticks are mice and other rodents, small mammals, birds (which are reservoirs for B burgdorferi) and white-tailed deer. Geographical distribution of Ixodes ticks is expanding in Canada and an increasing number of cases of Lyme disease are being reported. The present practice point reviews the epidemiology, clinical presentation, diagnosis, management and prevention of Lyme disease, with a focus on children.

Hepatitis B surveillance in Canada: 2005-2012.

To describe surveillance trends by age, sex and infection status of Hepatitis B (HB) virus in Canada between 2005 and 2012. Data on acute and chronic HB cases reported to the Canadian Notifiable Disease Surveillance System were compiled at the national level to examine trends by age and sex over time. Time trends are presented from 2005 to 2012, corresponding to the availability of data differentiated by acute and chronic infection status. The rate of reported acute HB infections decreased from 1.0 to 0.6 per 100,000 between 2005 and 2012. Both sexes showed rate decreases over this time, although acute HB rates were consistently higher among males than females. The rate of reported chronic HB infections decreased from 14.1 to 12.0 per 100,000 between 2009 and 2012. These results are based on data in which infection status was specified. The proportion of unspecified cases in any given year may somewhat alter the results. This is the first time that trends in reported cases and corresponding rates of HB in Canada have been examined by acute and chronic infection status using national surveillance data. Canada continues to have a downward trend in HB rates across Canada, most notably in acute HB cases. Increasing national capacity to differentiate between acute and chronic HB will facilitate a more thorough understanding of trends in transmission and of the burden of HB infection in Canada.

Cost effectiveness of darunavir/ritonavir combination antiretroviral therapy for treatment-naive adults with HIV-1 infection in Canada.

The AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS) clinical trial examined the efficacy and safety of two ritonavir-boosted protease inhibitors (PI/r), darunavir/r 800/100 mg once daily (QD) and lopinavir/r 800/200 mg daily, both used in combination with tenofovir disoproxil fumarate/emtricitabine. This study aimed to assess the cost effectiveness of the darunavir/r regimen compared with the lopinavir/r regimen in treatment-naive adults with HIV-1 infection in Canada. A Markov model with a 3-month cycle time and six CD4 cell-count-based health states (>500, 351-500, 201-500, 101-200, 51-100, and 0-50 cells/mm(3)) followed a cohort of treatment-naive adults with HIV-1 infection through initial darunavir/r or lopinavir/r combination therapy and a common set of subsequent regimens over the course of their remaining lifetimes. Population characteristics and transition probabilities were estimated from the ARTEMIS clinical trial and other trials. Costs (in 2014 Canadian dollars), utilities, and mortality were estimated from Canadian sources and published literature. Costs and health outcomes were discounted at 5% per year. One-way and probabilistic sensitivity analyses were performed, including a simple indirect comparison of the darunavir/r initial regimen with an atazanavir/r-based regimen. In the base-case lifetime analysis, individuals receiving initial therapy with the darunavir/r regimen experienced 0.25 more quality-adjusted life-years (QALYs) with lower antiretroviral drug costs (-$14,246) and total costs (-$18,402) than individuals receiving the lopinavir/r regimen, indicating that darunavir/r dominated lopinavir/r. In an indirect comparison with an atazanavir/r-based regimen, the darunavir/r regimen remained the dominant choice, but with lower cost savings (-$2,303) and QALY gains (0.02). Results were robust to a wide range of other changes in input parameter values, population characteristics, and modeling assumptions. The probabilistic sensitivity analysis demonstrated that the darunavir/r regimen was cost effective compared with the lopinavir/r regimen in over 86% of simulations for willingness-to-pay thresholds between $0 and $100,000 per QALY gained. Darunavir/r 800/100 mg QD may be a cost-effective PI/r component of initial antiretroviral therapy for treatment-naive adults with HIV-1 infection in Canada.

Lyme disease: clinical diagnosis and treatment.

Lyme disease is an emerging zoonotic infection in Canada. As the Ixodes tick expands its range, more Canadians will be exposed to Borrelia burgdorferi, the bacterium that causes Lyme disease. To review the clinical diagnosis and treatment of Lyme disease for front-line clinicians. A literature search using PubMed and restricted to articles published in English between 1977 and 2014. Individuals in Lyme-endemic areas are at greatest risk, but not all tick bites transmit Lyme disease. The diagnosis is predominantly clinical. Patients with Lyme disease may present with early disease that is characterized by a "bull's eye rash", fever and myalgias or with early disseminated disease that can manifest with arthralgias, cardiac conduction abnormalities or neurologic symptoms. Late Lyme disease in North America typically manifests with oligoarticular arthritis but can present with a subacute encephalopathy. Antibiotic treatment is effective against Lyme disease and works best when given early in the infection. Prophylaxis with doxycyline may be indicated in certain circumstances. While a minority of patients may have persistent symptoms, evidence does not demonstrate that prolonged courses of antibiotics improve outcome. Clinicians need to be aware of the signs and symptoms of Lyme disease. Knowing the regions where Borrelia infection is endemic in North America is important for recognizing patients at risk and informing the need for treatment.

Enhanced surveillance of invasive meningococcal disease in Canada, 2006-2011.

The purpose of this report is to describe the epidemiology of invasive meningococcal disease (IMD) in Canada from 2006 to 2011. Data from the Enhanced Invasive Meningococcal Disease Surveillance System and national population estimates were selected for descriptive and inferential analyses. The geographic, demographic, seasonal and subtype distributions as well as clinical characteristics of the IMD cases were examined. Incidence and mortality rates were calculated per 100,000 population per year; 95% confidence intervals (CI) were calculated for rate comparison. The direct method was used for age standardization. Proportions were compared using the chi-squared test at a p<0.05 significance level. During the study period, the mean incidence rates of IMD were 0.58 (total), 0.33 (serogroup B), 0.07 (serogroup C), 0.03 (serogroup W-135) and 0.10 (serogroup Y). The median age for serogroups B, C, W-135 and Y was 16, 43, 38 and 47 years respectively. The mean age-specific incidence rates among infants under 1 year of age (7.35, CI: 5.38-9.32) and children from 1 to 4 years of age (1.89, CI: 1.54-2.24) were significantly higher than those in any other age group. The mean case fatality ratio was 8.1% (range 4.3%-14.3%). The average number of cases that occurred per month was significantly higher (p<0.0001) in winter (18 cases) than in summer (12 cases). IMD is still endemic in Canada. Although individuals at any age can be affected, infants under 1 year of age are at the greatest risk, followed by children aged 1-4 years and individuals aged 15-19 years. Following the implementation of routine childhood immunization programs with monovalent meningococcal C conjugate vaccines (MenC) in all provinces and territories (beginning in 2007), the incidence of serogroup C has decreased significantly over the study period and is now at an all-time low. Serogroup B is the leading cause of IMD, and diseases of serogroup W-135 and Y have stabilized at relatively lower incidence rates. With the addition of immunization programs using quadrivalent conjugate meningococcal vaccines (MCV4), we would expect further reductions in the incidence of meningococcal infection in Canada.

The First Report of HIV-1 Group O Infection in Canada

We report here the first case of HIV-1 group O infection in Canada. The patient presented with a progressive decline in CD4+ T lymphocyte count despite an undetectable plasma viral load, due to an inability to detect group O infection by standard techniques. This in turn resulted in a delay in initiation of treatment.

Clinical and economic consequences of vancomycin and fidaxomicin for the treatment of Clostridium difficile infection in Canada.

Clostridium difficile infection (CDI) represents a public health problem with increasing incidence and severity. To evaluate the clinical and economic consequences of vancomycin compared with fidaxomicin in the treatment of CDI from the Canadian health care system perspective. A decision-tree model was developed to compare vancomycin and fidaxomicin for the treatment of severe CDI. The model assumed identical initial cure rates and included first recurrent episodes of CDI (base case). Treatment of patients presenting with recurrent CDI was examined as an alternative analysis. Costs included were for study medication, physician services and hospitalization. Cost effectiveness was measured as incremental cost per recurrence avoided. Sensitivity analyses of key input parameters were performed. In a cohort of 1000 patients with an initial episode of severe CDI, treatment with fidaxomicin led to 137 fewer recurrences at an incremental cost of $1.81 million, resulting in an incremental cost of $13,202 per recurrence avoided. Among 1000 patients with recurrent CDI, 113 second recurrences were avoided at an incremental cost of $18,190 per second recurrence avoided. Incremental costs per recurrence avoided increased with increasing proportion of cases caused by the NAP1/B1/027 strain. Results were sensitive to variations in recurrence rates and treatment duration but were robust to variations in other parameters. The use of fidaxomicin is associated with a cost increase for the Canadian health care system. Clinical benefits of fidaxomicin compared with vancomycin depend on the proportion of cases caused by the NAP1/B1/027 strain in patients with severe CDI.

Congenital cytomegalovirus infection in Canada: Active surveillance for cases diagnosed by paediatricians

To determine the rate of diagnosis; demographic, clinical and laboratory characteristics; and management of congenital cytomegalovirus (cCMV) cases identified by paediatricians in routine clinical practice in Canada. National active monthly surveillance of all clinically practicing general and subspecialty paediatricians in Canada was performed for cCMV from March 1, 2005 to February 28, 2008, through the Canadian Paediatric Surveillance Program. Forty-nine cases of cCMV infection were reported (4.5 per 100,000 births): 40.8% were born before 36 weeks' gestation; 55.1% had a birth weight <2500 g; and 28.6% and 30.6% were below the third percentile for weight and head circumference, respectively. The median maternal age was 23 years, and 18.4% were <20 years of age. Eight mothers (16.3%) were Aboriginal (non-Aboriginal birth prevalence 3.9 per 100,000; Aboriginal birth prevalence 15.8 per 100,000; P<0.005). The most common laboratory abnormality was thrombocytopenia (53.1%). Thirty-three (67.3%) infants exhibited neurological manifestations; ganciclovir therapy was administered to 12 (36.4%) and was not administered to 21 (63.6%) of the infants with neurological manifestations. Only a minority of the expected number of symptomatic cCMV-infected infants were reported in the present study. The majority of these severely affected infants, including those with neurological disease, are not being treated with ganciclovir. The present description of current diagnosis and practice highlights the need for more complete case identification in the population as well as the need for increased awareness of the optimal therapy for symptomatic cCMV.

Burden of disease and cost of chronic hepatitis C infection in Canada.

Chronic infection with hepatitis C virus (HCV) is a major cause of cirrhosis, hepatocellular carcinoma and liver transplantation. To estimate the burden of HCV-related disease and costs from a Canadian perspective. Using a system dynamic framework, the authors quantified the HCV-infected population, disease progression and costs in Canada between 1950 and 2035. Specifically, 36 hypothetical, age- and sex-defined cohorts were tracked to define HCV prevalence, complications and direct medical costs (excluding the cost of antivirals). Model assumptions and costs were extracted from the literature with an emphasis on Canadian data. No incremental increase in antiviral treatment over current levels was assumed, despite the future availability of potent antivirals. The estimated prevalence of viremic hepatitis C cases peaked in 2003 at 260,000 individuals (uncertainty interval 192,460 to 319,880), reached 251,990 (uncertainty interval 177,890 to 314,800) by 2013 and is expected to decline to 188,190 (uncertainty interval 124,330 to 247,200) in 2035. However, the prevalence of advanced liver disease is increasing. The peak annual number of patients with compensated cirrhosis (n=36,210), decompensated cirrhosis (n=3380), hepatocellular carcinoma (n=2220) and liver-related deaths (n=1880) are expected to occur between 2031 and 2035. During this interval, an estimated 32,460 HCV-infected individuals will die of liver-related causes. Total health care costs associated with HCV (excluding treatment) are expected to increase by 60% from 2013 until the peak in 2032, with the majority attributable to cirrhosis and its complications (81% in 2032 versus 56% in 2013). The lifetime cost for an individual with HCV infection in 2013 was estimated to be $64,694. Although the prevalence of HCV in Canada is decreasing, cases of advanced liver disease and health care costs continue to rise. These results will facilitate disease forecasting, resource planning and the development of rational management strategies for HCV in Canada.

Defining research priorities for bacterial sexually transmitted infections in Canada.

We aimed to define priority areas for research on chlamydia, gonorrhea, and syphilis in Canada through the use of a consensus method. A modified Delphi method was conducted, consisting of two online surveys and an in-person meeting. Participants included people working in bacterial sexually transmitted infections (STIs) across Canada, including clinicians, policy-makers, public health practitioners, and researchers. Consensus was achieved regarding the most important priority topics in bacterial STI research in Canada, within five general priority areas: the epidemiology of bacterial STIs, screening, partner notification and contact tracing, antimicrobial resistance, and identification of best practices for the prevention and control of bacterial STIs. The findings of this consensus process can be used to inform research efforts, which could contribute to more effective control of bacterial STIs in Canada.

In Vitro Activity of Fosfomycin against Escherichia coli Isolated from Patients with Urinary Tract Infections in Canada as Part of the CANWARD Surveillance Study

We tested 868 urinary isolates of Escherichia coli collected from 2010 to 2013 as part of the Canadian national surveillance study CANWARD against fosfomycin by using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method with MIC interpretation in accordance with the CLSI M100-S23 (2013) criteria. The concentrations of fosfomycin inhibiting 50 and 90% of the isolates were ≤1 and 4 μg/ml; 99.4% of the isolates were susceptible to fosfomycin.

BRIEF - SYNOPSIS OF THE HUMAN IMMUNODEFICIENCY VIRUS (HIV) SCREENING AND TESTING GUIDE.

BACKGROUND The Public Health Agency of Canada (PHAC) estimates that, in 2011, 25% of people living with HIV in Canada were undiagnosed. Hesitation to seek testing may arise from fear, stigma and discrimination associated with the HIV diagnosis and related risk behaviours. This guide is designed to complement existing efforts to support care providers involved in HIV testing, in order to reduce the number of undiagnosed HIV infections in Canada. APPROACH PHAC commissioned a literature review and consulted with provinces and territories, and key stakeholders, including people living with HIV/AIDS, academics, nurses, physicians, professional associations, non-governmental organizations, policy-makers, community workers, and legal and ethical experts. As a result, the recommendations outlined in the guide are based on the most up-to-date evidence and expert opinion. SCREENING AND TESTING GUIDE The consideration and discussion of HIV testing should be made a component of routine periodic medical care. Offering HIV testing routinely can help normalize testing, and address the multiple barriers to reducing the number of undiagnosed cases in Canada. Begin with a brief explanation to the client on how HIV is transmitted: through unprotected sex, the sharing of drug-use equipment, and from a pregnant mother to her child. Clients can then consider their own situation and indicate whether they would like to have an HIV test. Upon request, a risk assessment may be conducted. As with other tests, testing is voluntary and verbal consent is sufficient. Negative test results provide an opportunity to remind clients of those practices that can help them maintain an HIV-negative status. There are a range of referrals and resources available to assist clients in reducing at-risk activities and maintaining a negative status. Those who are part of a couple should be encouraged to discuss HIV testing with their partners so they're not unknowingly involved in a serodiscordant relationship. Positive test results should always be provided in person and ideally by the initial care provider who has information resources and support referrals at the ready. An HIV positive diagnosis can be difficult news; it is important to take the time to discuss the results and answer any questions the client might have. Focus on positive messages by highlighting advances in HIV care, treatment and support. Note that HIV is now considered a chronic illness, and people living with HIV can live long, active and healthy lives. Advise the client about strategies for managing HIV and link them to care. Provide risk reduction information to prevent transmission Make the client aware that positive test results will be shared confidentially with the local public health department, which can assist in notifying previous and current partners of the need to be tested while protecting the client's anonymity and privacy. Strategies for informing past, current and future partners can be reviewed. If not already completed with the HIV test, clients should be tested for other STIs, hepatitis B and C, and tuberculosis.

An exploratory study on the mental health of immigrants, refugees and non-status people living with HIV in Toronto

Purpose– Canadian HIV/AIDS researchers, service providers and policy-makers are faced with new challenges of providing effective and inclusive care that meets the needs of the changing populations infected with and affected by HIV. Since 2005 immigrants and refugees from ethno-racial minority communities have comprised close to 20 percent of all new HIV infections in Canada. Anecdotes shared by PLWHAs and service providers indicated that mental health challenges faced by newcomer PLWHAs was a priority concern for HIV prevention, treatment and care. This paper reports on the results of an exploratory study, which examined the complex factors that influence the mental health of immigrants and refugees living with HIV/AIDS (IR-PLWHAs).Design/methodology/approach– This exploratory study is informed by a critical social science paradigm, which acknowledges that the everyday reality is shaped by interlocking systems of social processes and unequal power relations. The paper used a qualitative interpretative design and focus groups to explore the intersecting effects of living with HIV/AIDS, migration and settlement, and HIV stigma and discrimination on the mental health of IR-PLWHAs.Findings– The paper found that in addition to social and economic marginalization, IR-PLWHAs experienced multiple stressors associated with their HIV status: neurocognitive and physical impairments, HIV stigma and discrimination, and fear of deportation. The paper also found that the experiences of stigma and discrimination among IR-PLWHAs were complex and contextual, closely linked to their social positions defined by the intersecting dimensions of race, class, gender, citizenship, sexualities, body norms, and HIV status. The paper concludes that effective HIV prevention, treatment and care, and mental health promotion in newcomer and ethno-racial minority communities must consider the bio-psycho-social connections of different stressors and the interlocking systems of oppression faced by IR-PLWHAs.Research limitations/implications– This study was exploratory in nature with a small number of participants who were recruited through AIDS organizations in Toronto. Consequently, the recruitment strategy may reach only those who were connected to the AIDS organizations. The paper believes that IR-PLWHAs who were not connected to the AIDS organizations might experience even more social exclusion and marginalization. These factors may limit the transferability of this study.Originality/value– This is the first study that explores the bio-psycho-social connections and intersecting determinants of mental health among immigrants and refugees living with HIV and AIDS in Canada. The results of this study contribute to cross-sector dialogue among practitioners and researchers in the HIV/AIDS, mental health, and immigration and settlement services sectors.

Climate Change and West Nile Virus in a Highly Endemic Region of North America

The Canadian prairie provinces of Manitoba, Saskatchewan, and Alberta have reported the highest human incidence of clinical cases of West Nile virus (WNV) infection in Canada. The primary vector for WVN in this region is the mosquito Culex tarsalis. This study used constructed models and biological thresholds to predict the spatial and temporal distribution of Cx. tarsalis and WNV infection rate in the prairie provinces under a range of potential future climate and habitat conditions. We selected one median and two extreme outcome scenarios to represent future climate conditions in the 2020 (2010–2039), 2050 (2040–2069) and 2080 (2070–2099) time slices. In currently endemic regions, the projected WNV infection rate under the median outcome scenario in 2050 raised 17.91 times (ranged from 1.29-27.45 times for all scenarios and time slices) comparing to current climate conditions. Seasonal availability of Cx. tarsalis infected with WNV extended from June to August to include May and September. Moreover, our models predicted northward range expansion for Cx. tarsalis (1.06–2.56 times the current geographic area) and WNV (1.08–2.34 times the current geographic area). These findings predict future public and animal health risk of WNV in the Canadian prairie provinces.

Antimicrobial resistance of Salmonella enterica serovar Heidelberg isolated from poultry in Alberta

Salmonella enterica serovar Heidelberg is one of the top three serovars implicated in human infections in Canada. In 2003, the Canadian Integrated Program for Antimicrobial Resistance Surveillance reported antimicrobial resistance (AMR) in S. Heidelberg in Canada. The study objective was to investigate the AMR of S. Heidelberg isolated from poultry in Alberta. We examined 951 S. Heidelberg poultry isolates obtained during 1996 to 2010 and tested against 18 antibiotics using the Sensititre AVIAN1F system. Temporal resistance patterns were analysed using single-level logistic regression models. Continuous variables were included in the multivariable models. Multivariable models were built and variables and interactions were included in these final models. Data were analysed using Stata 11 Intercooled. Ceftiofur resistance ranged annually from 0 to 10.5% and gentamicin resistance ranged annually from 0 to 33.3%; no isolates were enrofloxacin resistant. Resistance to amoxicillin (annual range 0 to 42.6%) varied significantly by time and interaction with commodity type. Meat turkey S. Heidelberg isolates had higher ceftiofur resistance compared with chickens: layers plus layer breeders (odds ratio = 22.6, P < 0.01) and broiler breeders (odds ratio = 9.1, P < 0.01). Gentamicin resistance decreased significantly over the study period (odds ratio = 0.72 per year, P < 0.01). Tetracycline (TET) resistance changed significantly over time (annual range 0 to 39.6%), interacting with poultry commodity type. Meat turkey isolate TET resistance, higher overall than that of chicken, increased throughout the study. All turkey breeder isolates were resistant to TET. In conclusion, this study provides AMR data for S. Heidelberg isolates from the Alberta poultry industry and demonstrated significant trends in resistance, both temporal and between poultry commodities.

Gonorrhea as a Moving Target: How Do We Sharpen Our Aim and Strengthen Our Arrows?

J Obstet Gynaecol Can 2013;35(2):174–176 G is the second most commonly diagnosed and reported sexually transmitted infection in Canada,1 and is an important cause of cervicitis, urethritis, and pelvic inflammatory disease. The rate of gonorrhea in Canada reached its lowest point in 1997 after two decades of decline. Since then, there has been a steady increase, and the incidence of gonococcal infections more than doubled in Canada from 1997 to 2006.1

Hepatitis C Virus Infection in Canada’S First Nations People: A Growing Problem

Hepatitis C Virus Infection in Canada’S First Nations People: A Growing Problem

Integrated whole-genome sequencing and temporospatial analysis of a continuing Group A Streptococcus epidemic

Analysis of microbial epidemics has been revolutionized by whole-genome sequencing. We recently sequenced the genomes of 601 type emm59 Group A Streptococcus (GAS) organisms responsible for an ongoing epidemic of invasive infections in Canada and some of the United States. The epidemic has been caused by the emergence of a genetically distinct, hypervirulent clone that has genetically diversified. The ease of obtaining genomic data contrasts with the relatively difficult task of translating them into insightful epidemiological information. Here, we sequenced the genomes of 90 additional invasive Canadian emm59 GAS organisms, including 80 isolated recently in 2010–2011. We used an improved bioinformatics pipeline designed to rapidly process and analyze whole-genome data and integrate strain metadata. We discovered that emm59 GAS organisms are undergoing continued multiclonal evolutionary expansion. Previously identified geographic patterns of strain dissemination are being diluted as mixing of subclones over time and space occurs. Our integrated data analysis strategy permits prompt and accurate mapping of the dissemination of bacterial organisms in an epidemic wave, permitting rapid generation of hypotheses that inform public health and virulence studies.

The Disease Burden of Invasive Meningococcal Serogroup B Disease in Canada

Invasive meningococcal disease remains a rare but deadly infection in Canada. New serogroup B vaccines may offer the potential for prevention and control. This report examines the disease burden caused by serogroup B invasive meningococcal infections. From 2002 to 2011, active, population-based metropolitan area surveillance for adult and pediatric hospital admissions for adult and pediatric hospital admissions for laboratory-confirmed infection with Neisseria meningitidis, was conducted by the 12 centers of the Canadian Immunization Monitoring Program, Active. A total of 769 invasive meningococcal cases occurred from 2002 to 2011; 54% (n = 413) in children with a peak incidence of 6.16 (95% confidence interval: 3.18-10.76) per 100,000 in children aged <1 year in 2009. Serogroup B accounted for the largest proportion of cases and had the highest incidence of all serogroups across all ages, with a peak incidence of 0.31 (0.23-0.40) per 100,000 in 2007. Serogroup B case fatality rate was 4.3% in children, and 21% of pediatric survivors had sequelae. B:17:P1.19 ST-269 was the most frequently detected antigenic type. Serogroup B invasive meningococcal infections caused substantial morbidity and mortality and are the leading cause of invasive meningococcal disease in Canada. The proportion of cases potentially preventable with the new serogroup B vaccines should be evaluated to determine whether universal immunization programs are warranted.

Inhaled nitric oxide in patients with the acute respiratory distress syndrome secondary to the 2009 influenza A (H1N1) infection in Canada

H1N1 had a self-limited respiratory illness; however, if hospitalization was required, 20-36% of patients required admission to the intensive care unit (ICU), and 80% of those patients required invasive mechanical ventilation. The case mortality ranged from 17-40%. In many of these patients, conventional mechanical ventilation strategies were not adequate to reverse their severe oxygenation defects. Adjunctive therapies in addition to lung protective mechanical ventilation strategies are often trialed in patients with oxygenation failure (defined as PaO2 60 mmHg despite FIO2 of 1.0 and optimal positive endexpiratory pressure [PEEP]). Inhaled nitric oxide (iNO) is one such therapy that has shown an improvement in oxygenation in patients with acute respiratory distress syndrome (ARDS). 2,3 In this report, we describe the epidemiologic characteristics, clinical features, treatment, and outcome in the cohort of patients who had ARDS due to H1N1 and were treated with iNO, and we compare their results with those of patients who did not receive iNO. Following approval by the University of Manitoba Biomedical Research Ethics Board, we conducted a retrospective chart review of all patients who presented with confirmed H1N1 and were treated with iNO in the teaching intensive care units at the University of Manitoba’s two adult medical intensive care units. Baseline demographic and clinical data of patients are shown in the Table. After administration of iNO, there was a significant and sustained improvement in the PaO2 and PaO2 /F IO2 ratio at 24 hr, and this improvement persisted throughout the study period (seven days). Three patients in the iNO group eventually required extracorporeal membrane oxygenation due to their profound ARDS. There were two deaths in the iNO group (n = 9) vs ten deaths in the control group (n = 94), 22% and 11%, respectively. Previous work has shown only a transient improvement in these parameters that, in many cases, did not persist past 24 hr. This result is significant as it shows a sustained improvement in oxygenation in these patients with viral pneumonia.