Molecular genotyping studies often focus on clustered tuberculosis and recent transmission. Less attention has been paid to non-clustered tuberculosis. However, non-clustered cases also contribute significantly to the tuberculosis burden, especially in low-incidence countries. The objective of this study is to characterize non-clustered tuberculosis cases in Denmark and point out potential implications for tuberculosis control. The study is based on nationwide IS6110-RFLP genotyping of tuberculosis cases from 1992 through 2004, corresponding to 98% of culture verified cases. Of 3988 cases, 45% were non-clustered. Both Danes and immigrants had a peak incidence of non-clustered tuberculosis at older ages, 80-89 years (4.3 cases/10(5) population/year) and 60-69 years (28.8 cases/10(5) population/year), respectively. In addition, immigrants had a peak at 20-29 years (43.2 cases/10(5) inhabitants/year). In Danes, the incidence of non-clustered tuberculosis decreased during the study period and was predominantly found in elderly persons, presumably reactivating infection acquired during 1910-40, when tuberculosis incidence was high. In immigrants, the incidence was high at all ages, presumably reflecting reactivation of imported infections. In the future, the number of non-clustered tuberculosis cases will decrease, as older Danes die, and as time since primary infection increases for immigrants residing in Denmark. TB control should include focus on non-clustered cases.
Studies of diabetes in migrant populations have shown a higher prevalence compared to their respective countries of origin and to people natively born in the host country, but there is little population-based data on diabetes incidence and mortality in migrant populations. The aim of the current study was (1) to describe the incidence rates and prevalence of diabetes among first generation migrants in Denmark compared to the Danish background population, and (2) to compare standardised mortality rates (SMRs) for individuals with and without diabetes according to country of origin.
Information was obtained from linkage of the National Diabetes Register with mortality statistics and information from the Central Personal Register on country of origin. Age- and sex-specific estimates of prevalence, incidence rates, mortality rates and SMRs relative to the part of the population without diabetes were calculated based on follow up of the entire Danish population.
Compared with native born Danes, the incidence of diabetes was about 2.5 times higher among migrants from Africa, Asia, and the Middle East, and these migrant groups also showed significantly higher prevalence. The standardised mortality rates (SMR) were higher particularly above 50years of age among most migrant groups compared with native born Danes, and with a higher annual increase.
The highest diabetes incidence rates and prevalence estimates were observed among migrants from Africa, Asia, and the Middle East, and the annual increase in SMRs was higher in these groups compared to native born Danes.
Department of Epidemiology, University of Michigan, Ann Arbor, Michigan; Department of Infectious Diseases, Odense University Hospital, Odense, Denmark; Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark; International Reference Laboratory of Mycobacteriology, Statens Serum Institut, Copenhagen, Denmark; Medical Department, Queen Ingrid's Hospital, Nuuk, Greenland.
Abstract. Extrapulmonary tuberculosis (EPTB) is an important health problem that may cause serious morbidity and diagnostic challenges. We conducted a case-control study involving 5,684, approximately 99% of bacteriologically confirmed TB patients (including 1,925 EPTB cases) diagnosed in Denmark and Greenland during 1992-2007 to gain insight to the role of host factors in EPTB pathogenesis. Among patients from Somalia and Asia, persons 25-44 and 45-64 years of age were more likely to have EPTB than persons 15-24 years of age. In contrast, among persons from Greenland, the two oldest age groups were significantly less likely to have EPTB than the youngest age group. For all the age groups, the odds for having EPTB was significantly higher among patients from Somalia and Asia and significantly lower among the patients from Greenland than among patients from Denmark. Furthermore, the occurrence of specific types of EPTB significantly varied among different age groups or origins.
Department of Nursing, University College Capital, Hilleroed, Denmark, Research Centre for Migration, Ethnicity and Health (MESU), Section of Health Services Research, University of Copenhagen, Copenhagen, Denmark and Department of Public Health, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
Human migration caused by political unrest, wars and poverty is a major topic in international health. Infectious diseases like tuberculosis follow their host, with potential impact on both the migrants and the population in the recipient countries. In this study, we evaluate Mycobacterium tuberculosis transmission between the national population and migrants in Denmark.
Register study based on IS6110-RFLP results from nationwide genotyping of tuberculosis cases during 1992 through 2004. Cases with 100% identical genotypes were defined as clustered and part of a transmission chain. Origin of clusters involving both Danes and migrants was defined as Danish/migrant/uncertain. Subsequently, the proportion of cases likely infected by the "opposite" ethnic group was estimated.
4,631 cases were included, representing 99% of culture confirmed cases during 1992 through 2004. Migrants contributed 61.6% of cases. Up to 7.9% (95% CI 7.0-8.9) of migrants were infected by Danes. The corresponding figure was 5.8% (95% CI 4.8-7.0) for Danes. Thus, transmission from Danes to migrants occurred up to 2.5 (95% CI 1.8-3.5) times more frequent than vice versa (OR = 1). A dominant strain, Cluster-2, was almost exclusively found in Danes, particular younger-middle-aged males.
Transmission between Danes and migrants is limited, and risk of being infected by the "opposite" ethnic group is highest for migrants. TB-control efforts should focus on continues micro-epidemics, e.g. with Cluster-2 in Danes, prevention of reactivation TB in high-risk migrants, and outbreaks in socially marginalized migrants, such as Somalis and Greenlanders. Fears that TB in migrants poses a threat for resident Danes seem exaggerated and unjustified. We believe this to be true for other low incidence countries as well.
INTRODUCTION: Transmission of Mycobacterium tuberculosis (MT) in most cases requires extended exposure. OBJECTIVES: To document that MT transmission may occur even after very short exposure. MATERIAL AND METHODS: All first-time culture-confirmed tuberculosis (TB) cases in Denmark have since 1992 been subjected to genotyping, using the IS6110-Restriction Fragment Length Polymorphism (RFLP) technique. A young nurse with no risk factors developed pulmonary TB: the DNA pattern of her MT strain was compared to The Danish TB Subtyping Database, comprising >6000 DNA patterns from TB patients nationwide. RESULTS: Only one single MT DNA pattern matched the DNA profile of the isolate from the nurse. The pattern originated from a patient shortly admitted to the department where she worked at the time. MT transmission had occurred in spite of very short exposure. CONCLUSION: By adding modern molecular epidemiological methods to traditional epidemiological surveys, a more detailed picture of MT-transmission pathways can be obtained, showing that MT transmission can occur even after extremely short exposure. This stresses the necessity for adequate respiratory protection among hospital staff taking care of patients with pulmonary symptoms suspected for TB.
Tuberculosis (TB) is caused by pathogenic species within the Mycobacterium tuberculosis complex (MTBC). In the present case, a 40-year-old African man was admitted acutely. Despite negative microscopy, anti-TB treatment was initialized. Thirteen hours after hospitalisation, the patient suffered circulatory failure and died. Post mortem material from the lungs and pericardia tested positive for MTBC and was identified as Mycobacterium africanum by a new molecular method that enables identification of six of the eight MTBC species and provides clinicians with species-specific results.
In Denmark the tuberculosis (TB) incidence rates per 100.000 individuals per year have decreased from 162 in the 1920s to 6. Greenland is a highly endemic country for TB with an incidence rate that parallels that of India. Nine per cent of the Greenlandic children are infected with Mycobacterium tuberculosis. The global TB burden of disease is levelling off - even showing a small reduction in the estimated annual incidence rates. Drug resistance and HIV co-infection as well as diabetes pose great challenges in achieving the WHO/Stop TB partnership goals set out for 2015 and 2050.