L E G I
O N E L L A
Legionella are small gram-negative rod-shaped bacteria. Over 40 individual
species of Legionella are known. The majority of human infections are caused by
the species Legionella
pneumophila. Legionella pneumophila was
first discovered following a pneumonia outbreak at the 1976 Convention of the
American Legion in Philadelphia.
EFFECTS IN HUMANS:
There are two forms
of Legionellosis: Pontiac Fever and the more severe Legionnaires' Disease.
which is characterized by flu-like systems (fever, chills, headache and muscle
pain) lasting 2-5 days:
Pontiac Fever is a less severe form of Legionellosis which is characterized by
flu-like systems (fever, chills, headache and
muscle pain) lasting 2-5 days.
Legionnaires' Disease is a potentially fatal illness involving pneumonia.
relatively resistant to standard water disinfection procedures and can occur in
potable water. Early symptoms include muscle pain, loss of appetite, headache,
high fever, dry cough, chills, confusion, disorientation, nausea, diarrhea and
vomiting. Later symptoms chest pain and difficulty breathing. It is difficult to
distinguish this disease from other pneumonias. Early diagnosis and treatment
are extremely important. Treatment consists of intrvenous administration of
EFFECTS IN ANIMALS:
There are no
reports of naturally infected animals.
Legionella are most
commonly found in water, including ground water, fresh and marine surface waters
and potable (treated) water. Legionella are protected against standard water
disinfection techniques by their symbiotic relations with later microorganisms.
These bacteria have been found in water distribution systems of hospitals,
hotels, clubs, public buildings, homes and factories. Other waters in which
Legionella have been found include cooling towers, evaporative condensers and
whirlpools. These bacteria may be transmitted from potable water to air by
faucets, showerheads, cooling towers and nebulizers.
transmitted directly from the environment to humans. There is no evidence of
human-to-human transmission of these bacteria. Potable water is the most
important source of Legionella. Humans may inhale contaminated aerosals or
aspirate small amounts of contaminated drinking water. No vaccine is available
to prevent infection.