TY - JOUR
T1 - Migrant tuberculosis: the extent of transmission in a low burden country
AU - Kamper-Jørgensen, Zaza
AU - Andersen, Aase Bengaard
AU - Kok-Jensen, Axel
AU - Kamper-Jørgensen, Mads
AU - Bygbjerg, Ib Christian
AU - Andersen, Peter Henrik
AU - Thomsen, Vibeke Ostergaard
AU - Lillebaek, Troels
PY - 2012/3/18
Y1 - 2012/3/18
N2 - Background: 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.Methods: 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.Results: 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.Conclusions: 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.
AB - Background: 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.Methods: 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.Results: 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.Conclusions: 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.
KW - Adult
KW - Aged
KW - Aged, 80 and over
KW - Cluster Analysis
KW - DNA Transposable Elements
KW - Denmark
KW - Disease Transmission, Infectious
KW - Female
KW - Genotype
KW - Humans
KW - Male
KW - Middle Aged
KW - Molecular Epidemiology
KW - Molecular Typing
KW - Mycobacterium tuberculosis
KW - Polymorphism, Restriction Fragment Length
KW - Transients and Migrants
KW - Tuberculosis
U2 - 10.1186/1471-2334-12-60
DO - 10.1186/1471-2334-12-60
M3 - Journal article
C2 - 22423983
SN - 1471-2334
VL - 12
JO - B M C Infectious Diseases
JF - B M C Infectious Diseases
M1 - 60
ER -
