Population-Based Laboratory Surveillance of Imported Malaria in Metropolitan Calgary, 2000–2011

Increased travel leads to a heightened risk of imported infectious diseases. Patterns of immigration to countries like Canada have changed such that countries of malaria endemicity are frequented in larger numbers. In keeping with the changes in travel patterns and immigration, the major metropolitan city of Calgary has seen a dramatic rise in malaria incidence over the last decade. Fuelling this rise in Calgary has been the apparent complacence with prophylaxis in individuals visiting friends and relatives and potentially inadequate public health intervention in areas of the city with increased immigration and lower socioeconomic status.     

Projection of tuberculosis incidence with increasing immigration trends

Tuberculosis (TB) incidence rates vary substantially from regions to regions and from countries to countries. In countries such as Canada where TB incidence rate is low, increasing immigration trends may have significant impact on the TB transmission patterns in these countries. In this study we formulate a deterministic epidemiological model of TB transmission in two demographically distinct populations: Canadian born and foreign born populations, in order to investigate the effects of this demographic distinction on the short-term incidence and long-term transmission dynamics, and with special emphasis on the impact of immigration latent TB cases on the overall TB incidence rate in the whole population.     

Trends in colorectal cancer incidence and related lifestyle risk factors in 15⿿49-year-olds in Canada, 1969⿿2010

BackgroundWhile the overall incidence rate of colorectal cancer (CRC) in Canada has been decreasing, some countries show an increasing incidence in those under the age of 50. We examined the trends in CRC incidence and associated lifestyle risk factors in Canadians aged 15⿿49.MethodsIncidence data for colorectal, colon and rectum/rectosigmoid cancers were obtained for 1969⿿2010 from the Canadian Cancer Registry, and trends in age-standardized incidence rates (ASIRs) were examined by Joinpoint regression for three age groups (15⿿29, 30⿿39, 40⿿49 years) and by sex. Trends in the prevalence of some CRC risk factors were similarly examined from national health surveys for various periods ranging from 1970 to 2012.ResultsIn both sexes combined, ASIRs rose by 6.7%/year (1997⿿2010) for 15⿿29-year-olds, 2.4%/year (1996⿿2010) for 30⿿39-year-olds, and 0.8%/year (1997⿿2010) for 40⿿49-year-olds. Similar trends were observed by sex. The rise in ASIR was more rapid for cancers of the rectum/rectosigmoid compared to colon for all age groups. Risk factor trends varied: excess weight rose substantially, vegetables and fruit consumption increased slightly, physical inactivity rates declined but remained high, alcohol consumption changed little, and smoking rates declined. Data on red/processed meat consumption were unavailable.ConclusionThe ASIR of CRC in young Canadians has increased since about the mid-1990s. The rising prevalence of excess weight in younger generations has likely played a role in the CRC trend, but more research is needed.     

Smallpox Control in Canada

During the period 1961 to 1963 there were 10 separate importations of smallpox cases by aircraft into England and Wales, Germany, Sweden, Poland and Canada. A feature of the resulting outbreaks was the number of cases and deaths of physicians and other health personnel. With the increasing volume of international air traffic there is a risk of importing incubating cases of smallpox into Canada, as occurred in 1962. Millions of Canadians have been protected against smallpox. Some complications of smallpox vaccination have occurred in Canada; such complications can be minimized by proper attention to contraindications to vaccination. The Food and Drug Directorate, Department of National Health and Welfare, has circularized all physicians in Canada to request their co-operation in reporting adverse reactions to drugs. This includes serious, unusual or unsuspected reactions to immunizing agents (vaccines, toxoids and antitoxins). The latter information will be shared with the Epidemiology Division, Department of National Health and Welfare, and the provincial epidemiologist and manufacturer concerned. The importance of maintaining the smallpox immunity of physicians, nurses and other hospital and health personnel in Canada is emphasized.     

A syndromic approach to common parasitic diseases

Standard textbooks discuss parasitic disease according to specific organisms. In contrast, patients with parasitic infections present to physicians with a variety of clinical manifestations that may involve any of several organ systems and that often mimic nonparasitic diseases. A syndromic approach to the clinical situation may help the physician in considering the most important parasitic agents. Many parasitic infections can be acquired in temperate climates. While often considered tropical or exotic, other parasitic diseases are now seen more frequently in developed countries because of immigration and increased world travel. In this review the clinical syndromes associated with common parasitic diseases in North America are discussed, with an emphasis on risk factors and diagnosis of specific infections.     

Prevalence of risk factors for cardiovascular disease in Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992

BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.     

A Quantitative and Novel Approach to the Prioritization of Zoonotic Diseases in North America: A Public Perspective

Background

Zoonoses account for over half of all communicable diseases causing illness in humans. As there are limited resources available for the control and prevention of zoonotic diseases, a framework for their prioritization is necessary to ensure resources are directed into those of highest importance. Although zoonotic outbreaks are a significant burden of disease in North America, the systematic prioritization of zoonoses in this region has not been previously evaluated.

Methodology/Principal Findings

This study describes the novel use of a well-established quantitative method, conjoint analysis (CA), to identify the relative importance of 21 key characteristics of zoonotic diseases that can be used for their prioritization in Canada and the US. Relative importance weights from the CA were used to develop a point-scoring system to derive a recommended list of zoonoses for prioritization in Canada and the US. Over 1,500 participants from the general public were recruited to complete the online survey (761 from Canada and 778 from the US). Hierarchical Bayes models were fitted to the survey data to derive CA-weighted scores. Scores were applied to 62 zoonotic diseases of public health importance in Canada and the US to rank diseases in order of priority.

Conclusions/Significance

This was the first study to describe a systematic and quantitative approach to the prioritization of zoonoses in North America involving public participants. We found individuals with no prior knowledge or experience in prioritizing zoonoses were capable of producing meaningful results using CA as a novel quantitative approach to prioritization. More similarities than differences were observed between countries suggesting general agreement in disease prioritization between Canadians and Americans. We demonstrate CA as a potential tool for the prioritization of zoonoses; other prioritization exercises may also consider this approach.     

Costs and benefits of freedom from shrimp diseases in the European Union

The growth in penaeid shrimp aquaculture has been mirrored by the emergence of a number of serious diseases, some of which (e.g. white spot syndrome virus - WSSV) spread rapidly across the globe through movement of infected stock. The World Organisation for Animal Health (OIE) lists six penaeid shrimp pathogens of which three are notifiable in the EU: WSSV (listed as non-exotic to the EU), Taura syndrome virus (TSV) and yellow head disease (YHD) (both listed as exotic). EU Member States (MS) must determine a status for non-exotic diseases (e.g. disease free, unknown, infected). In developing a policy for WSSV, import risk analysis (IRA) can be used to systematically assess the risks of introduction and justify risk mitigation to maintain freedom. OIE guidelines recommend that countries assess the risk of disease introduction via commodities, not listed by the OIE as safe, and apply sanitary measures if necessary. The sanitary measures necessary to maintain freedom from WSSV may not be compatible with current EU animal health legislation. The recent revision by OIE of products listed as safe for international trade strengthens the case for the risks of TSV and YHD introduction into the EU to be assessed. Freedom from WSSV is an important criterion for the development of shrimp aquaculture in the EU. However, in developing disease control policy, governments need to balance the potentially competing interests of all stakeholders, including consumers. Thus economic modelling of the impact of possible sanitary measures on consumer prices of imported products is needed to support decision making. The creation of disease free compartments and post-import risk mitigation for commodities may create the conditions conducive to the development of shrimp aquaculture whilst minimising the costs of maintaining disease freedom.     

Evolutionary Aspects of Emerging Lyme Disease in Canada

In North America, Lyme disease (LD) is a tick-borne zoonosis caused by the spirochete bacterium Borrelia burgdorferi sensu stricto, which is maintained by wildlife. Tick vectors and bacteria are currently spreading into Canada and causing increasing numbers of cases of LD in humans and raising a pressing need for public health responses. There is no vaccine, and LD prevention depends on knowing who is at risk and informing them how to protect themselves from infection. Recently, it was found in the United States that some strains of B. burgdorferi sensu stricto cause severe disease, whereas others cause mild, self-limiting disease. While many strains occurring in the United States also occur in Canada, strains in some parts of Canada are different from those in the United States. We therefore recognize a need to identify which strains specific to Canada can cause severe disease and to characterize their geographic distribution to determine which Canadians are particularly at risk. In this review, we summarize the history of emergence of LD in North America, our current knowledge of B. burgdorferi sensu stricto diversity, its intriguing origins in the ecology and evolution of the bacterium, and its importance for the epidemiology and clinical and laboratory diagnosis of LD. We propose methods for investigating associations between B. burgdorferi sensu stricto diversity, ecology, and pathogenicity and for developing predictive tools to guide public health interventions. We also highlight the emergence of B. burgdorferi sensu stricto in Canada as a unique opportunity for exploring the evolutionary aspects of tick-borne pathogen emergence.     

Ethical models underpinning responses to threats to public health: a comparison of approaches to communicable disease control in Europe

Increases in international travel and migratory flows have enabled infectious diseases to emerge and spread more rapidly than ever before. Hence, it is increasingly easy for local infectious diseases to become global infectious diseases (GIDs). National governments must be able to react quickly and effectively to GIDs, whether naturally occurring or intentionally instigated by bioterrorism. According to the World Health Organisation, global partnerships are necessary to gather the most up-to-date information and to mobilize resources to tackle GIDs when necessary. Communicable disease control also depends upon national public health laws and policies. The containment of an infectious disease typically involves detection, notification, quarantine and isolation of actual or suspected cases; the protection and monitoring of those not infected; and possibly even treatment. Some measures are clearly contentious and raise conflicts between individual and societal interests. In Europe national policies against infectious diseases are very heterogeneous. Some countries have a more communitarian approach to public health ethics, in which the interests of individual and society are more closely intertwined and interdependent, while others take a more liberal approach and give priority to individual freedoms in communicable disease control. This paper provides an overview of the different policies around communicable disease control that exist across a select number of countries across Europe. It then proposes ethical arguments to be considered in the making of public health laws, mostly concerning their effectiveness for public health protection.     

Smoking and health

Cigarette smoking is the leading cause of preventable death and disease in Canada, accounting for some 30 000 deaths annually. This enormous health cost to Canadians has led the Canadian Medical Association (CMA) to promote initiatives regarding smoking prevention programs in schools, legislation to prevent smoking in government buildings and controls on smoking in private buildings, particularly places of work. The CMA recommends the prohibition of all forms of tobacco advertising/promotion in Canada, including advertising in conjunction with athletic events. The CMA also supports the taxation of tobacco products at a level to discourage their purchase, with revenue earmarked for health budgets, and the association is encouraging the federal government to develop alternative crop incentives for tobacco farmers. The norm of nonsmoking is a social attitude the CMA is working toward developing in all Canadians.     

Information Seeking Regarding Tobacco and Lung Cancer: Effects of Seasonality

This paper conducted one of the first comprehensive international Internet analyses of seasonal patterns in information seeking concerning tobacco and lung cancer. Search query data for the terms “tobacco” and “lung cancer” from January 2004 to January 2014 was collected from Google Trends. The relevant countries included the USA, Canada, the UK, Australia, and China. Two statistical approaches including periodogram and cross-correlation were applied to analyze seasonal patterns in the collected search trends and their associations. For these countries except China, four out of six cross-correlations of seasonal components of the search trends regarding tobacco were above 0.600. For these English-speaking countries, similar patterns existed in the data concerning lung cancer, and all cross-correlations between seasonal components of the search trends regarding tobacco and that regarding lung cancer were also above 0.700. Seasonal patterns widely exist in information seeking concerning tobacco and lung cancer on an international scale. The findings provide a piece of novel Internet-based evidence for the seasonality and health effects of tobacco use.     

Tropical medicine for the 21st century.

The specialty of tropical medicine originated from the needs of the colonial era and is removed from many of the health care requirements of tropical countries today. Tropical medicine concentrates on parasitic diseases of warm climates, although other infections and diseases related to poverty rather than climate dominate medicine in developing countries challenged by population pressure, civil strife, and migration. In the new century, tropical medicine would best be absorbed into the specialty of infectious diseases, which should incorporate parasitic diseases, travel medicine, and sexually transmitted diseases. Pressing questions for health care and research in developing countries concern the provision of appropriate services for problems such as HIV/AIDS, tuberculosis, sexually transmitted diseases, and injuries. The question of how to provide appropriate clinical care in resource poor settings for the major causes of morbidity and premature mortality has been neglected by donors, academic institutions, and traditional tropical medicine.     

Sex matters: secular and geographical trends in sex differences in coronary heart disease mortality

ObjectiveTo examine secular trends and geographical variations in sex differences in mortality from coronary heart disease and investigate how these relate to distributions in risk factors.Design National and international data were used to examine secular trends and geographical variations in sex differences in mortality from coronary heart disease and risk factors.SettingEngland and Wales, 1921-98; Australia, France, Japan, Sweden, and the United States, 1947-97; 50 countries, 1992-6.ResultsThe 20th century epidemic of coronary heart disease affected only men in most industrialised countries and had a very rapid onset in England and Wales, which has been examined in detail. If this male only epidemic had not occurred there would have been 1.2 million fewer deaths from coronary heart disease in men in England and Wales over the past 50 years. Secular trends in mean per capita fat consumption show a similar pattern to secular trends in coronary heart disease mortality in men. Fat consumption is positively correlated with coronary heart disease mortality in men (r_s=0.79; 95% confidence interval 0.70 to 0.86) and inversely associated with coronary heart disease mortality in women (−0.30; −0.49 to −0.08) over this time. Although sex ratios for mortality from coronary heart disease show a clear period effect, those for lung cancer show a cohort effect. Sex ratios for stroke mortality were constant and close to unity for the entire period. Geographical variations in the sex ratio for coronary heart disease were associated with mean per capita fat consumption (0.64; 0.44 to 0.78) but were not associated with the sex ratio for smoking.ConclusionSex differences are largely the result of environmental factors and hence not inevitable. Understanding the factors that determine sex differences has important implications for public health, particularly for countries and parts of countries where the death rates for coronary heart disease are currently increasing.

What is already known on this topic

Mortality for coronary heart disease is greater in men than women in most industrialised countriesThe most widely accepted explanation for this difference is that women are protected by oestrogen

What this study adds

The sex difference in mortality from coronary heart disease varies over time and between countries in a way that cannot be explained by endogenous oestrogenThese trends indicate that sex differences in mortality from coronary heart disease are driven primarily by environmental factorsSex differences in coronary heart disease are not inevitableUnderstanding more about the factors that cause the sex differences in mortality from coronary heart disease has important public health implications     

Immigration,Transition into Adult Life and Social Adversity in Relation to Psychological Distress and Suicide Attempts among Young Adults

Background

The increasing incidence of mental health problems among young people is a major concern in many Western countries. The causal mechanisms underlying these trends are not well established, but factors influenced by current societal changes ought to be implicated. Such factors include immigration and social adversity as well as the timing of taking on adult social roles (e.g. gainful employment, parenthood and own housing tenure). We therefore examined relationships between these factors and the risks of psychological distress as well as suicide attempts in young adults, with a focus on gender differences.

Methods

We conducted a population-based study including 10,081 individuals aged 18–29, recruited in 2002 and 2006 in Stockholm, Sweden. Data were collected by record linkage and questionnaires.

Results

Non-European immigrants had an increased risk of distress, and female non-European immigrants had a markedly higher risk of suicide attempts. Both early parenthood (≤24 years) and not being a parent, being a student and the lack of own housing tenure were associated with distress, but only in women. In both sexes, financial strain was associated with the increased risk of distress and suicide attempts, while unemployment was only associated with distress.

Conclusions

Immigration from outside Europe and social adversity are associated with mental health problems in young adults, especially females. Postponed transition into adulthood is associated with poor mental health in young women. These factors are influenced by current societal changes, and may have contributed to the increasing incidence of mental health problems among young people in Western countries.     

The benefits of privatization.

The promise of a universal, comprehensive, publicly funded system of medical care that was the foundation of the Medical Care Act passed in 1966 is no longer possible. Massive government debt, increasing health care costs, a growing and aging population and advances in technology have challenged the system, which can no longer meet the expectations of the public or of the health care professions. A parallel, private system, funded by a not-for-profit, regulated system of insurance coverage affordable for all wage-earners, would relieve the overstressed public system without decreasing the quality of care in that system. Critics of a parallel, private system, who base their arguments on the politics of fear and envy, charge that such a private system would "Americanize" Canadian health care and that the wealthy would be able to buy better, faster care than the rest of the population. But this has not happened in the parallel public and private health care systems in other Western countries or in the public and private education system in Canada. Wealthy Canadians can already buy medical care in the United States, where they spend $1 billion each year, an amount that represents a loss to Canada of 10,000 health care jobs. Parallel-system schemes in other countries have proven that people are driven to a private system by dissatisfaction with the quality of service, which is already suffering in Canada. Denial of choice is unacceptable to many people, particularly since the terms and conditions under which Canadians originally decided to forgo choice in medical care no longer apply.     

The alluring myth of private medicine.

Canada''s medicare system has provided Canadians with high-quality health care for almost three decades. Now Canadian health care appears to be at risk of losing the single-payer system, which is the premise on which medicare is built. As medicare comes under increasing financial pressure, many are calling for the introduction of private care as a means of bolstering our health care system and maintaining its quality. Although it appears alluring to some politicians, physicians and commentators, privatization could very well lead to the demise of the principles and practices of the Canadian health care system as we know it, with little clear benefit to the public or physicians.     

“We Went Out to Explore,But Gained Nothing But Illness”: Immigration Expectations,Reality, Risk and Resilience in Chinese-Canadian Women with a History of Suicide-Related Behaviour

Suicide is a complex and tragic outcome driven by biological, psychological, social and cultural factors. Women of Chinese descent and women who have immigrated to other countries have higher rates of suicidal ideation and behaviour, and immigration-related stress may contribute. To understand the experiences of immigration and their relationship with distress and suicide-related behaviour in Chinese women who have immigrated to Canada. 10 semi-structured qualitative interviews with Chinese women who have immigrated to Toronto, Canada and have a history of suicide-related behaviour were completed and analyzed using a constructivist grounded theory methodology. Immigration-related and acculturation stress stemmed from unmet expectations and harsh realities. These repeated experiences resulted in hopelessness, helplessness, and alienation, which are risk factors for suicide and suicide-related behaviour. However, immigration-related support can also increase hope, self-efficacy and connectedness to foster recovery and resilience. This is the first qualitative study focusing on immigration experiences and its relationship to suicide-related behaviour in Chinese immigrant women. Knowledge of immigration and acculturation stressors can a) help identify and support women at risk for suicide and b) form a target for social intervention for all immigrant women, regardless of suicide risk.     

National trends in rates of death and hospital admissions related to acute myocardial infarction,heart failure and stroke, 1994–2004

Background

Rates of death from cardiovascular and cerebrovascular diseases have been steadily declining over the past few decades. Whether such declines are occurring to a similar degree for common disorders such as acute myocardial infarction, heart failure and stroke is uncertain. We examined recent national trends in mortality and rates of hospital admission for these 3 conditions.

Methods

We analyzed mortality data from Statistic Canada’s Canadian Mortality Database and data on hospital admissions from the Canadian Institute for Health Information’s Hospital Morbidity Database for the period 1994–2004. We determined age- and sex-standardized rates of death and hospital admissions per 100 000 population aged 20 years and over as well as in-hospital case-fatality rates.

Results

The overall age- and sex-standardized rate of death from cardiovascular disease in Canada declined 30.0%, from 360.6 per 100 000 in 1994 to 252.5 per 100 000 in 2004. During the same period, the rate fell 38.1% for acute myocardial infarction, 23.5% for heart failure and 28.2% for stroke, with improvements observed across most age and sex groups. The age- and sex-standardized rate of hospital admissions decreased 27.6% for stroke and 27.2% for heart failure. The rate for acute myocardial infarction fell only 9.2%. In contrast, the relative decline in the inhospital case-fatality rate was greatest for acute myocardial infarction (33.1%; p < 0.001). Much smaller relative improvements in case-fatality rates were noted for heart failure (8.1%) and stroke (8.9%).

Interpretation

The rates of death and hospital admissions for acute myocardial infarction, heart failure and stroke in Canada changed at different rates over the 10-year study period. Awareness of these trends may guide future efforts for health promotion and health care planning and help to determine priorities for research and treatment.Cardiovascular disease, including stroke, is the leading cause of death globally. Therefore, changes in the incidence and mortality of these disorders have a major impact on the overall health of a country’s population and on the health care system.¹ Rates of death from cardiovascular and cerebrovascular disease have been steadily declining in Western Europe and North America for the past 3 decades.^2,3 Whether this decline is occurring to a similar degree for common conditions such as acute myocardial infarction, heart failure and stroke is uncertain. Although these 3 conditions are associated with several common risk factors, the relative importance of risk factors such as smoking, hypertension and hyperlipidemia differs between them.⁴ Furthermore, the rate of new therapeutic advances for these conditions has varied in both the acute, in-hospital setting and in the outpatient setting, where primary and secondary prevention of events occurs.A comparative evaluation of recent population-based trends in incidence and mortality would provide an assessment of the relative progress achieved in preventing and treating these important conditions. Furthermore, the substantial economic impact of cardiovascular disease, including stroke, on the health care system — estimated at $18 billion per year in direct and indirect costs in Canada in 1998⁵ — underscores the need for continued monitoring of cardiovascular disease and treatment outcomes. A study of temporal trends could also help guide future health promotion activities and health care planning.We conducted a study of recent trends in the rates of death and hospital admissions for acute myocardial infarction, heart failure and stroke in Canada from 1994 to 2004. We also studied whether changes in these trends occurred at similar rates in younger and older Canadians and in both sexes.     

Type 2 diabetes and cardiovascular disease: getting to the fat of the matter

The increasing national prevalence of obesity is a major public health concern and a substantial burden on the health care resources of Canada. In addition to the direct health impact of obesity, this condition is a well-established risk factor for the development of various prevalent comorbidities including type 2 diabetes, hypertension, and cardiovascular disease. Historically, adipose tissue has been regarded primarily as an organ for energy storage. However, the discovery of leptin in the mid 1990's revolutionized our understanding of this tissue and has focused attention on the endocrine function of adipose tissue as a source of secreted bioactive peptides. These compounds, collectively termed adipokines, regulate a number of biological functions including appetite and energy balance, insulin sensitivity, lipid metabolism, blood pressure, and inflammation. The physiological importance of adipokines has led to the hypothesis that changes in the synthesis and secretion of these compounds in the obese are a causative factor contributing to the development of obesity and obesity-related diseases in these individuals. Following from this it has been proposed that pharmacologic manipulation of adipokine levels may provide novel effective therapeutic strategies to treat and prevent obesity, type 2 diabetes, and cardiovascular disease.