Piecing the puzzle together: foreign-born tuberculosis in an immigrant-receiving country.

In major immigrant-receiving countries, annual foreign-born tuberculosis (TB) case counts and rates are relatively constant. Why this is so, and who might be a high-yield target for screening for latent TB infection, remain open questions. Foreign-born TB in Canada during 1986-2002 was retrospectively examined using national TB and immigration data as well as census data. Case counts and rates were analysed in relation to demographics, immigration period and time since arrival. Pre-1986 immigrants (n=3,860,853) and 1986-2002 immigrants (n=3,463,283) contributed 8,662 and 9,613 TB cases, respectively. Immigrants arriving ≤ 5 yrs ago and those arriving >10 yrs ago contributed almost equally to the annual foreign-born TB case count despite a 3.5-fold difference in in-country person-yrs. Remarkably stable and relatively low TB incidence was observed among immigrants >10 yrs post-arrival. Conversely, TB incidence within 5 yrs of arrival was dynamic, demonstrating a strong inverse association with time since arrival and higher sensitivity to changes in immigration level than shifts toward higher incidence source countries. Relative constancy in foreign-born TB incidence is explained by a complex convergence of several factors. Immigrants born in high-incidence countries who arrived ≤ 2 yrs ago and were aged 15-34 yrs upon arrival constitute high-yield targets for preventive therapy.

Immigration medical screening and HIV infection in Canada.

HIV infection, particularly associated with AIDS, is often used by migrant screening nations to exclude entry into the country. The unique feature of the Canadian immigration HIV screening programme is that it was not primarily for determining inadmissibility of HIV-positive applicants, but for health promotion and disease prevention purposes. All applicants over 15 years of age for permanent residency or temporary residency from designated countries are HIV antibody tested. This includes persons seeking asylum from within Canada. The highest rates of HIV infection were found in migrant applicants from high prevalence areas of the world and reflected the demographic profile of the source region (predominately women). The majorities of HIV-positive persons are exempt from exclusion from Canada due to class of application (refugee, family) or are already in Canada (refugee claimant). Significant issues in notification, reporting and programme management have been identified as a consequence of this programme.

Results of tuberculosis screening in applicants for migration in Vietnam and Cambodia.

SETTING: Pre-migration medical screening programmes in Ho Chi Minh City, Vietnam and Phnom Penh, Cambodia. OBJECTIVE: To compare the rates of newly diagnosed bacteriologically confirmed tuberculosis (TB) in a cohort of migration applicants in Vietnam and Cambodia with current estimates of the TB burden in these countries. DESIGN: Interviews and medical screening of 5108 Vietnamese and 910 Cambodian migration applicants who applied for an Australian visa. RESULTS: On initial testing, the rate of bacteriologically confirmed TB among the Vietnamese cohort was 157 per 100,000 population compared to 989/100,000 among the Cambodian cohort. When cases detected during follow-up testing were included, the rate in the Vietnamese cohort was 489/100,000 compared to 1209/100,000 in the Cambodian cohort. CONCLUSIONS: Although it has been suggested that the rate of newly diagnosed bacteriologically confirmed TB among migration applicants would underestimate the prevalence of TB in the Vietnamese and Cambodian populations, the rates found were substantially higher than current point estimates of the prevalence of TB, particularly for Vietnam. Our findings suggest that current published estimates of the tuberculosis burden in Vietnam and Cambodia may be conservative.

The association between subjective and clinical indicators of health in prospective Vietnamese migrants.

We conducted a cross-sectional survey of 1669 prospective Vietnamese migrants who had applied to migrate to Australia to describe the association between self-reported health status and several commonly used clinical indicators of health among prospective Vietnamese migrants. Participants were recruited from the International Organization for Migration's standardised medical screening program.' We found that clinical indicators of health are related to self-reported health status among prospective Vietnamese migrants. Self-reported health status, which was assessed using a modified version of the Short Form-36 health survey, was significantly associated with clinical indicators of health, including the number of body system abnormalities identified during medical screening, evidence of tuberculosis on chest radiograph, and self-reported weight loss over the previous six months. These findings support the validity of self-reported health status assessment among prospective migrants, although the assessment of subjective indicators of health during compulsory medical screening may be limited by reporting bias.

Malaria, intestinal parasites, and schistosomiasis among Barawan Somali refugees resettling to the United States: a strategy to reduce morbidity and decrease the risk of imported infections.

In 1997, enhanced health assessments were performed for 390 (10%) of approximately 4,000 Barawan refugees resettling to the United States. Of the refugees who received enhanced assessments, 26 (7%) had malaria parasitemia and 128 (38%) had intestinal parasites, while only 2 (2%) had Schistosoma haematobium eggs in the urine. Mass therapy for malaria (a single oral dose of 25 mg/kg of sulfadoxine-pyrimethamine) was given to all Barawan refugees 1-2 days before resettlement. Refugees >2 years of age and nonpregnant women received a single oral dose of 600 mg albendazole for intestinal parasite therapy. If mass therapy had not been provided, upon arrival in the United States an estimated 280 (7%) refugees would have had malaria infections and 1,500 (38%) would have had intestinal parasites. We conclude that enhanced health assessments provided rapid on-site assessment of parasite prevalence and helped decrease morbidity among Barawan refugees, as well as, the risk of imported infections.

Tuberculosis rates among migrants in Australia and Canada.

Multiple linear regression analysis was used to compare the regression coefficients for Australia and Canada on the association between tuberculosis (TB) rates among migrants and the estimated incidence in the country of birth. Regression coefficients predicting the rate of TB among migrants based on the incidence of TB in the country of birth are not significantly different between populations of migrants in Australia and Canada. Our findings support the ability of the incidence of TB in the country of birth to predict variation in the incidence of TB in migrants groups in two migration receiving countries. This information can be used to focus TB treatment and prevention efforts towards high-risk groups.

Arrest and detention in international travelers.

BACKGROUND: Our objective was to examine the characteristics of international travelers from Canada who have been arrested or detained while abroad, and to review the health implications of incarceration. METHOD: An EpiInfo 6 program was created to analyse all of the Consular reports received in 1995 via the Secure Integrated Global Network (SIGNET) which provides communications and computerization services to the Department of Foreign Affairs and International Trade, Canada. The Consular Management and Operations System was designed to support the delivery of consular services by the Department, and to link Headquarters in Ottawa with missions in other countries through case management files, including a "Prisoners" file. Information obtained included personal demographics (age, gender), date, country, and reason for arrest or detention, and outcome of judicial process. RESULTS: There were 1, 086 arrest or detention reports received from Consular services via SIGNET in 1995. Males outnumbered females 5.6:1. Most individuals arrested were young: 57.5% were less than 40 years, and 79% were less than 50 years. Drug related charges were cited in 33.1% of all cases, with 52.8% of arrested females charged with drug related offenses. The documented conviction rate was 96%. The majority of detained Canadian travelers were held in countries within the Americas (791 cases - 69.2%), with 642 (59.1%) being detained in the USA. CONCLUSIONS: Arrest and detention is an unusual occurrence for international travelers but relative youth, male gender, and female drug couriers were identifiable risk characteristics. Public awareness campaigns can be targeted to specific population demographics, but all international travelers need to be counseled on the consequences of transgressing laws in foreign countries.

Death and dying abroad: the Canadian experience.

BACKGROUND: The objective was to examine the characteristics of international travelers from Canada, who have died while abroad, and to review the health protection and promotion strategies for prevention of adverse health outcomes associated with travel, which may have prevented these deaths. METHOD: An EpiInfo 6 program was created to analyse all of the Consular reports received in 1995 via the Secure Integrated Global Network, which provides communications and computerization services to the Department of Foreign Affairs and International Trade, Canada. The Consular Management and Operations System was designed to support the delivery of consular services by the Department, and to link Headquarters in Ottawa with missions in other countries, through case management files, including a "Death Abroad" file. The type of data collected included personal demographics (age, gender), date, country, and cause of death. RESULTS: In 1995, consular services received 309 reports of Canadians dying abroad. Two hundred and twenty deaths were males (71.2%), and 69 were females (22.3%). The average age (56 years) and median age (43 years) were similar for males and females (age range 0.3-86 years). Recorded causes of death were: natural (62.1%), accidents (24.9%), murder (7.8%), and suicide (5.2%). Cardiovascular disease and trauma were the two most commonly specified causes of death. CONCLUSIONS: At least 36% of the deaths occurring in Canadian travelers would be considered preventable. Pretravel medical interventions for travelers with known preexisting medical problems, may have prevented many more deaths. International travelers need to be aware of the health risks associated with travel. Access to appropriate health risk assessment, prior to exposure, in many cases, would have prevented death abroad.

Screening and treatment of immigrants and refugees to Canada for tuberculosis: Implications of the experience of Canada and other industrialized countries.

OBJECTIVE: To assess the incidence of tuberculosis in immigrants and refugees in Canada and other industrialized countries; the effectiveness of the screening process; the incidence of drug resistance; recommendations for prophylaxis and therapy; and indications for and effectiveness of directly observed therapy. DATA SOURCES: medline search of literature published from 1985 to 1995 with the key words 'tuberculosis', 'Canada', 'screening', 'drug resistance', 'drug resistance, multiple', 'immigration and emigration', and the title words 'directly observed therapy'. STUDY SELECTION: All studies reporting data on incidence, the outcomes of screening, drug resistance, therapy and directly observed therapy were selected. DATA SYNTHESIS AND CONCLUSIONS: Data synthesis led to the conclusions that immigrants and refugees to Canada have five times the nonimmigrant and non-Aboriginal rate of tuberculosis; that screening programs discover new cases of tuberculosis on and after arrival and that up to 20% of those scheduled to attend a tuberculosis clinic after arrival may never attend; that drug resistance is widespread in countries from which Canada receives immigrants; and that directly observed therapy for active cases can result in 100% conversion rates.

Development of a Vietnamese version of the Short form-36 Health Survey.

We aimed to test the psychometric properties of a culturally relevant translation of the medical outcomes study short form-36 health survey (SF-36) with prospective Vietnamese migrants. The translated survey was interviewer-administered to 1610 Vietnamese aged over 15 years who had applied to migrate to Australia. All but two SF-36 items had good discriminant validity, and all eight scales of the Vietnamese version of the SFS-36 had good discriminant validity, which supports the use of SF-36 constructs to assess self-reported health status among Vietnamese migrants. However, the mental health, vitality and bodily pain scales demonstrated low internal consistency. This finding is likely to be a product of the increased diversity among scale items following modifications to improve cultural relevance. Further modifications to improve the internal consistency of these scales are required.

The sero-prevalence of antibodies to trypanosoma cruzi in Latin American refugees and immigrants to Canada.

BACKGROUND: Chagas' disease is caused by infection with the protozoan agent Trypanosoma cruzi. An estimated sixteen to eighteen million people are infected in Latin America. Outside of endemic regions, Chagas' disease may be transmitted through the transfusion of infected blood components, congenital infection and organ transplantation. We sought to determine the sero-prevalence of antibodies to T. cruzi in a community sample of Latin American refugees and immigrants to Canada. METHODS: This was a sero-prevalence study in Latin American refugees and immigrants living in Canada. Eligible subjects were born in South America, Central America or in Mexico. Participants were recruited from a variety of community settings, as well as from medical clinics. Serum was tested by enzyme-linked immunoassay for antibodies to T. cruzi. RESULTS: A total of 102 participants were enrolled. One sample tested positive for antibodies for T. cruzi. The seroprevalence in our sample was 1.0% (95% CI: 0.2%- 5.3%). INTERPRETATION: We found a low sero-prevalence of Chagas' disease in a community sample of Latin American immigrants and refugees. Physicians who treat Latin American immigrants should consider the risk profile and clinical status of the individual in their decision to screen for Chagas' disease.

Balancing prevention and screening among international migrants with tuberculosis: population mobility as the major epidemiological influence in low-incidence nations.

BACKGROUND: Tuberculosis infection and disease remain a significant cause of global morbidity and mortality. The burden of tuberculosis disease is greatest in the developing nations of the world, although the effect of imported disease is observed in low-incidence tuberculosis regions, represented predominantly by high-income countries. In these regions, national tuberculosis control and elimination programmes are increasingly challenged to address disease in foreign-born residents. Immigration policies and shifting migration patterns over the past 5 decades have brought larger numbers of permanent and temporary residency migrants from high-prevalence regions of the world into low tuberculosis incidence environments. As a consequence, both national immigration policies and global health strategies for the control of tuberculosis share common interest in mobile populations moving from high-to-low prevalence regions. Existing immigration medical screening practices in major immigrant-receiving nations were often designed to prevent and manage the importation of contagious, active pulmonary tuberculosis disease. Such programmes may be limited in addressing the long-term consequences of latent tuberculosis infection in foreign-born residents. In nations with a low incidence of tuberculosis, a direct link can be found between the globalization of health factors related to international population movements, as observed with tuberculosis and immigration policies and practices. Continued migration from high-endemic tuberculosis regions will increasingly influence the disease burden in low-endemic areas, and challenge local tuberculosis control and elimination programmes. Evidence-based approaches to meeting those challenges will allow for the effective use of resources and support ongoing programme evaluation.

Population mobility and infectious diseases: the diminishing impact of classical infectious diseases and new approaches for the 21st century.

In an increasingly globalized world, rapid population mobility and migration is reducing the differences in infectious disease epidemiology between regions of the world. The movement and relocation of populations between locations where the prevalence and incidence of infections are markedly different poses current and future challenges to those involved in clinical infectious diseases and public health program management. Historically, international attention has focused on the screening and treatment of acute infections of epidemic potential, but, as immigration significantly changes the demography of many nations, chronic infections will require increased attention. In countries with large mobile populations, the population-based burden of infections with long latency periods or significant noninfectious sequelae will make up an increasing amount of the infectious disease caseload and will require more-modern approaches than the traditional screening of arrivals. The globalization of chronic infectious disease epidemiology will require corresponding development of integrated programs to anticipate and manage these diseases in response to an increasingly mobile patient population.

Health issues associated with the smuggling and trafficking of migrants.

Approximately 4 million persons annually may be smuggled illegally across international borders. In 1997 it was estimated that 700,000 women or children were smuggled across international borders, of whom 175,000 were estimated to come from the former Soviet bloc; approximately 45,000-50,000 smuggled women and children arrived in the United States in that year. This article develops a framework to consider the impact of human trafficking on health within the context of migrant health and the destination population's health. Health risks are assumed by the individual being smuggled during the pre-journey, migratory, and arrival phases. In addition, the recipient country's population may also incur additional health burdens related to illegal arrivals from higher disease prevalence areas of the world. Some of this disease risk potential may be from transmissible agents, but there is increasing concern, and some evidence, that noncontagious diseases may be a significant problem associated with human trafficking. The global consideration of human smuggling and the individual and social impact on health are the focus of this paper.

Human mobility and population health. New approaches in a globalizing world.

The globalization of economies in the last 25 years has greatly increased both the number of people on the move and the rapidity of their movement, and has brought attention to global disparities in health determinants and to the health of migrant populations themselves. Differences in epidemiological disease risk (prevalence gaps) may have negative, neutral, or positive health consequences for the migrant or receiving population. Population mobility represents a growing challenge to the development of public health programs and legislative policies to prevent the importation of disease, and to promote and protect the health of migrants and the local, receiving population. The inability to detect and contain imported disease threats at national borders requires a shift in immigration, quarantine, and public health approaches to health and mobile populations. A new paradigm is needed to facilitate the development of policies and programs to address the health consequences of population mobility.

Human plague in India, August-October, 1994.

As of 9 October, the total number of fatalities in India due to plague was 55 (52 from Surat city and 3 from New Delhi). Reasons for the low case-fatality ratio remain to be determined and will require more detailed and reliable clinical and laboratory information. Additional studies into the patterns of transmission in the infected areas are underway or anticipated. By 14 October reports of both suspect and confirmed cases had decreased. The area around the Beed district in the state of Maharashtra was also declared as "infected" under the definition of the International Health Regulations. A WHO expert committee has been in the affected areas and detailed reports are anticipated.

Effect of radiosensitizing agents on electron transport systems.

Experiments have been carried out to study the interaxtion between chemical radiosensitizing agents and model electron transport systems. Using an NAD(P)H:O2 oxidoreductase enzyme as such a model, it was demonstrated that radiosensitizers can act as intermediates in the transfer of electrons from NADH to O2, even in the presence of classical inhibitors of electron transport, with anefficiency related to both their redox potentials and their radiosensitizing abilities. This work which was further confirmed in mammalian mitochondria and microsomes as well as in a cultured cell system indicated that these sensitizers can accept electrons from a variety of organelle systems. This action was shown to be related to the concentration of reduced pyridine nucleotides present both in vivo and in vitro. Of the electron-affinic agents tested, those whose redox potential was more negative than -0.39 V may possibly serve as better radiotherqpeutic mediators.