Doubling of the tuberculosis incidence in Greenland over an 8-year period (1990-1997)

To determine the trends in conventional and molecular epidemiology of tuberculosis (TB) in Greenland over an 8-year period.

A nation-wide, retrospective, population-based study of all cases of TB reported to the National Health Division of Greenland from 1 January 1990 to 31 December 1997. An analysis of microbiology data including RFLP results.

The annual incidence increased from 85/100,000 in 1990 to 172/100,000 in 1997; 335 (72%) of the cases were culture-positive. On average 58% of culture-positive cases were smear-positive, with an increase from 40% in 1990 to 69% in 1997. There was a significant increase in childhood TB from four cases in 1990 to 26 in 1997. RFLP analysis shows that 15% of the patients were infected with unique strains and 85% were infected with strains belonging to one of 20 clusters. There were four major clusters, comprising respectively 52, 34, 26 and 14 patients.

There was a dramatic increase in TB cases in Greenland from 1990 to 1997. The increase is due to micro-epidemics in small isolated settlements, and affects primarily young adults and children. RFLP analysis confirms this observation and indicates confined, local transmission. In this context RFLP is not useful as the only parameter for monitoring recent transmission.