No 49 - 2010

Tuberculosis 2009, part I

2009 saw a total of 329 notified cases of tuberculosis (TB), 114 (35 %) in persons of Danish origin and 215 (65 %) in immigrants or descendants. The overall incidence was 6.0 per 100,000.

The M/F ratio was 2.4 for Danes and 1.1 for immigrants. The median age was 51 years (0-86 years) for Danes and 34 years (0-96 years) for immigrants. Table 1 shows the distribution by part of country and ethnicity.

Information on concurrent HIV infection and therefore AIDS was provided in five cases, one Dane and four immigrants. As previously explained, this should be regarded a minimum number, EPI-NEWS 51/09 (pdf).

A total of 41 (12 %) patients were notified with relapse, including 17 Danes, eight Somalis and Greenlanders.

Alcohol abuse and/or homelessness were noted for 38 patients (12 %) of whom 23 were Danes and 15 immigrants. 
Table 2 shows the distribution of TB by localization and ethnicity.

Development in tuberculosis since 1990 is shown in Figure 1.

Country of infection and ethnicity

A total of 139 cases were infected in Denmark, including 100 of Danish origin. A total of 39 immigrants were presumably infected in Denmark, including 18 from Greenland, eight from Somalia and the remaining cases from eight other countries.

Seven Danes were presumably infected in Africa (3), Asia (3) or Greenland (1). For the remaining seven Danes, the country of infection was unknown.

A total of 123 immigrants were presumably infected in their countries of origin, including 20 Somalians, eight Thais, eight Greenlanders, seven Pakistanis and seven Indians.
For a total of 53 immigrants, the country of infection was unknown.

TB among children

A total of 20 cases of TB in children below the age of 15 years were notified, including 11 (55 %) below the age of five years.

Six children were Danes; all had been infected in Denmark. Among 14 immigrant children, eight (57 %) were infected in Denmark and the remaining six (43 %) in their countries of origin.

A total of 15 (75 %) children, including six Danes were probably infected by a family member.

A total of 17 (85 %) children, including five Danes and 12 immigrants, had pulmonary TB.

Two children, one Danish and one immigrant, had TB-meningitis, and one immigrant child had TB of the lymph-nodes.

Occupational infection

A total of ten cases were registered as occupational infections, seven Danes and three immigrants.

Six cases were healthcare professionals/hospital employees who may have been exposed to TB infection, four of these were Danes and two were immigrants, including one immigrant from a highly endemic area. Two persons had possibly become infected in Denmark while serving as social workers, one was Danish and the other was from a highly endemic area.
Two employees had possibly been exposed to TB infection at bars, both were Danes.

In none of the ten cases did the notification provide any specific information on the source of the infection, which could help render probable occupational infection by comparison to the DNA subtypes of any isolates. DNA subtyping is performed on all first-time isolates and then every three months if the patient remains culture positive.

(P.H. Andersen, Dept. of Epidemiology, D. Bang, Mycobacteriology Lab.)

Comments will follow in part II.

Individually notifiable diseases and selected laboratory diagnosed infections (pdf)

8 December 2010