[Legionella infections--an underestimated disease group].

As in other countries, pneumonia due to Legionella bacteria occurs in Denmark. Even so, legionellosis is rarely diagnosed and often late in the course of illness. This may be due both to the variable and nonspecific clinical picture of the infection, and to the fact that currently available diagnostic methods are inadequate in a clinical context. Even in severe cases, the prognosis of Legionnaires' disease is quite good, if adequate antibiotic therapy is instituted early in the course of illness. The treatment of Legionnaires' disease differs from the treatment of most other pneumonias; frequently, therapy must be completed solely on a basis of clinical suspicion. The present diagnostic state may be improved by an increased awareness of the disease and its clinical manifestations, as well as by improved laboratory diagnosis.