Two hundred and fifty six cases of tuberculosis were reported
in Norway in 2002 (5.7 cases per 100 000 population) (1). This included 208
new cases (with no previous tuberculosis diagnosis) and 48 recurrent cases
(with previous tuberculosis diagnosis). Of the 256 patients, 195 patients
(76%) were born outside Norway. One hundred and two of the foreign born patients
were born in Africa and 63 in Asia. Pulmonary tuberculosis was diagnosed in
61% of all cases.
Transmission of tuberculosis in Norway has been very low for many years,
and the majority of Norwegian patients who fall ill were infected prior
to the availability of tuberculostatic drugs. The foreign born population
in Norway is younger and arrived from countries with a high prevalence of
tuberculosis, so the age distribution of their tuberculosis cases is much
younger (figure 1).
Figure 1. Notified cases of tuberculosis in Norway 2002
by age, sex and place of birth
Seventy six percent of all the tuberculosis cases, and 77% of the pulmonary
cases, were culture positive. Of the 42 isolates from patients born in Norway
that were examined for drug resistance in 2002, one was isoniazid resistant
and none were multidrug resistant (MDR-TB), that is, showing resistance
to both isoniazid and rifampicin. Of the 150 isolates from patients born
outside Norway that were examined for drug resistance, 21 showed resistance
to isoniazid. Seven of these were also resistant to rifampicin. This is
the highest number of MDR-TB ever reported in Norway, representing 2.7 %
of all tuberculosis cases.
The incidence of tuberculosis has steadily decreased in the Norwegian born
population. Following increased immigration, the number of reported cases
in the foreign born population has increased since the late 1980s, which
explains why the overall incidence rate has been unchanged in recent years
(figure 2). In subgroups, such as people who were born in Africa, the incidence
rate is about as high as it is in these people’s countries of origin (2).
The incidence rate of tuberculosis in Norway is among the lowest in the
world. Despite a rise in MDR-TB cases in 2002, it is still a rare condition
in Norway. Increased vigilance is needed to prevent these cases by early
detection and effective treatment of all tuberculosis patients
One African born patient who was diagnosed with polyresistant tuberculosis
(resistant to more than one drug but not to both isoniazid and rifampicin)
in 1994 later developed MDR-TB due to poor management. According to fingerprint
analysis (RLFP) this case had been the source of 22 secondary cases of polyresistant
(nine cases) or MDR-TB (13 cases) by June 2003 (3).
Figure 2. Tuberculosis notifications in Norway 1977-2002
by country of birth
Main prevention strategies
A new national regulation and a manual on the prevention and control of
TB came into force at the beginning of 2003 (4,5). Tuberculosis coordinators
are appointed at regional level to ensure the implementation of the regulations.
These regulations fully comply with the DOTS strategy (http://www.who.int/gtb/dots/index.htm)
promoted by the World Health Organization and the International Union Against
Tuberculosis and Lung Diseases (IUATLD, http://www.iuatld.org).
Directly observed therapy (DOT) is obligatory for all tuberculosis patients
throughout the treatment period. Tuberculin skin tests are compulsory for
all asylum seekers and other immigrants entering Norway. In addition, chest
x ray is compulsory for all immigrants over the age of 15 years.
Early diagnosis, combined therapy, and a close follow up of patients during
treatment remain the main preventive strategy, in addition to more frequent
treatment of latent infection. In addition, much emphasis is put on contact
tracing in cases of infectious pulmonary disease. In Norway, contact tracing
detects one new tuberculosis case for every ten index cases (5). BCG vaccination
was introduced in 1947 and until 1995 was a compulsory part of the national
immunisation programme for children at 14 years of age. Since then, BCG
vaccine has been a voluntary vaccine, like the rest of vaccines in the programme.
The vaccination coverage has remained high, estimated at 99% in 2001. Children
in immigrant families are offered BCG vaccine at birth or when they arrive