Table 5

Proportion of TB transmitted with varying definition of mixed cluster origin

*

Likely origin of clusters

(based on numbers of Danes/migrants in the individual cluster)

Proportion of TB cases likely

due to transmission

Odds

ratio

Danish

(most Danes)

migrant

(most migrants)

uncertain

(even number)

Ethnic composition

of cluster

Mixed

Danish

Mixed

Migrant

Mixed

% (95% CI)

% (95% CI)

OR (95% CI)

Ehnicity of case

Migrants

n

Danes

n

Danes

n

Migrants

n

Danes

n

Migrants

n

Migrants

n

Danes

n

From migrants

to Danes

From Danes

to migrants

Origin of

mixed clusters

by criteria,

Criteria 1 **

225

800

303

560

104

685

0

0

5.8 (CI 4.8-7.0)

7.9 (CI 7.0-8.9)

1.4 (CI 1.1-1.8)

Criteria 2 **

205

796

303

558

87

685

22

21

5.0 (CI 4.0-6.1)

7.3 (CI 6.4-8.3)

1.5 (CI 1.2-1.9)

Criteria 3 **

200

822

303

554

52

685

31

30

3.0 (CI 2.3-3.9)

7.1 (CI 6.2-8.1)

2.5 (CI 1.8-3.4)

Criteria 4 **

179

761

303

523

45

685

83

98

2.7 (CI 2.0-3.6)

6.5 (CI 5.6-7.5)

2.5 (CI 1.8-3.5)

Criteria 5 **

204

803

303

567

85

685

14

16

4.8 (CI 3.9-5.9)

7.2 (CI 6.3-8.2)

1.5 (CI 1.2-2.0)

* Cases are represented by clustered M. tuberculosis isolates, genotyped by IS6110-RFLP/Spoligo in Denmark, 1992-2004. Mixed clusters: n = 105. Cases in mixed clusters: mmigrants: n = 785, Danes: n = 904.

** Criteria:

1: Origin of first patient in cluster defines cluster origin

2: Origin of first sputum smear positive patient in cluster defines cluster origin

3: Origin of most patients in cluster defines cluster origin

4: Origin of the 2/3 criteria met defines cluster origin

5: Origin of the 3/3 criteria met defines cluster origin

Kamper-Jørgensen et al. BMC Infectious Diseases 2012 12:60   doi:10.1186/1471-2334-12-60