Migrant tuberculosis: the extent of transmission in a low burden country

<p>Abstract</p> <p>Background</p> <p>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 <it>Mycobacterium tuberculosis </it>transmission between the national population and migrants in Denmark.</p> <p>Methods</p> <p>Register study based on IS<it>6110</it>-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.</p> <p>Results</p> <p>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.</p> <p>Conclusions</p> <p>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.</p

Effect of sex, age, and race on the clinical presentation of tuberculosis:A 15-year population-based study

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