83
Besides pneumonia, we can find patients that present amild illness, self-
limited and of short duration called Pontiac Fever, which is characterized
by: high temperature, myalgia, general unease, headache, with rare or absent
respiratory symptoms and absence of pneumonia.
Almost 50%of thepatientswithLegionnaires’ diseasepresent symptoms
associated to the central nervous system as: headache, lethargy, confusion
and stupor, and, less frequently, we observe: ataxia, coma and convulsions.
3 - Taxonomy
The
Legionellaceae
family consists of as single genus called
Legionella
.
We have knowledge of 52 species and 71 distinct serogroups in the
Legionella
genus isolated from human biological samples or environmental sources.
Twenty-three species were associated to disease in humans.Several species
recently described are intracellular parasites that are obligatory for free-
living amoebas.
Approximately, 80 to 90% of the reported cases of Legionnaires’ disease
are attributed to the
Legionella
pneumophila
, however, all the species can
cause infection, mainly in immunocompromised hosts. There are 16
serogroups of
Legionella pneumophila
. About 85% of the published cases of
Legionellosis were caused by
L. pneumophila
with the serogroups 1 and 6
liable for up to 75% of the illnesses in human beings.
