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Characterization of Legionnaires’ disease in Portugal
Legionnaires’ disease was first described in Portugal in 1979 (WHO
Bulletin) and is an under-reported disease. There are cases diagnosed by
several laboratories in the country that still do not report to the DDO system
(compulsory National Reported Diseases). Besides under–reported, it is
believed that this disease is also under-diagnosed. During a Symposium,
held in Lisbon on 2 of April of 2004 a communication by Filipe Froes,
member of the Portuguese Society for Pulmonology estimated that the new
cases in Portugal should be between 500 and 3500 per year.
Studies by Stout; Yu, 1997 and Chang, Yu, 2005 reference
Legionella
as the fourth leading cause of microbial community acquired pneumonia,
together with Streptococcus pneumoniae, Haemophilus influenzae and
Chlamydia pneumonia (respectively as the first, second and third causes).
The same authors rate infections by
Legionella
as 3-15% of all community-
acquired pneumonias.
Morbidity and mortality due to Legionnaires’ disease and Pontiac fever
are difficult to estimate. Most episodes of these diseases, whether stand-
alone or of epidemic origin are not included in Public Health statistical
overviews. Existing data thus does not permit the reliable estimation of the
incidence rates of these diseases in the Portuguese population (Veríssimo,
2000).
The incidence of Pontiac fever in the general population is totally
unknown. However, in the known epidemic cases, the incidence was higher
than 95% of the exposed population. In epidemic cases of Legionnaires’
disease, the attack rate can reach 30%, considering the population groups
at risk (Verissimo, 2000).
