LEGIONELLA - World Health Organization

definite nosocomial Legionnaires’ disease in a person who was in hospital for
10 days before the onset of symptoms.
domestically acquired Cases of legionellosis acquired in patients’ homes.
drift Water droplets that are generated within a device (such as a
cooling tower or evaporative condenser), and carried in the
airflow without initial evaporation.
drift eliminator An inertial stripping device used to remove water droplets.
ecology The relationship between an organism and its environment.
endotoxin A substance found in the cell walls of Gram-negative bacteria
that can be extremely toxic to people, producing fever, shock,
and even death.
epitope Part of a foreign organism or its proteins that is recognized
by the immune system and targeted by antibodies, cytotoxic
T cells or both.
evaporative condenser Heat-transfer device, in which warm water is cooled by evaporation
in atmospheric air (also known as an evaporative fluid cooler
or closed circuit cooling tower).
extrapulmonary syndrome Caused when Legionella pneumophila spreads from the respiratory
system to the body (usually the heart, but also the spleen,
liver, kidney, bone and bone marrow, joints, inguinal and
intrathoracic lymph nodes and digestive tract). Extremely rare.
flow diagram A systematic representation of the sequence of steps or operations
used in the production or manufacture of a particular item.
Gram stain A technique used to identify bacteria, in which a violet dye —
followed by a red dye — is used to stain bacterial cell walls.
Gram-positive bacteria retain the violet dye; Gram-negative
bacteria appear red.
greywater Domestic wastewater that does not contain human wastes,
such as bath, shower, or washing machine water (also referred
to as sullage).
haemoptysis Coughing up blood.
hazard In the context of this document, a biological, chemical or
physical agent in water, or a condition of water, with the
potential to cause an adverse health effect.
hazard analysis The process of collecting and evaluating information on hazards
and conditions leading to their presence, for the purpose of
deciding which are significant for water safety and therefore
should be addressed in a water safety plan.
health-based target Target based on critical evaluation of health concerns; for
example, a target might be “no cases of legionellosis caused
by artificial water systems”.
0 LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS