LEGIONELLA - World Health Organization

performance targets Goals for water quality; typically expressed in terms of required
reductions of a substance of concern, or effectiveness in
preventing contamination.
pleura A thin membrane that covers the lungs (visceral pleura) and
lines the chest cavity (parietal pleura).
pleural effusion A collection of fluid inside the chest cavity around the lung.
pleural space Also known as the pleural cavity, this is the area between the
pleura (see above). The pleural space is normally filled with fluid.
polymicrobial Characterized by the presence of several species of
microorganisms.
Pontiac fever The mildest form of legionellosis (caused by Legionella
pneumophila); usually self-limited and typically does not
require treatment.
possible nosocomial Legionnaires’ disease in a person who was in hospital for
1–9 of the 10 days before the onset of symptoms, in a hospital
not previously known to be associated with any case of
Legionnaires’ disease, and where no microbiological link has
been established between the infection and the hospital (or the
residential institution).
probable nosocomial Legionnaires’ disease in a person who was in hospital for
1–9 of the 10 days before the onset of symptoms, and either
became ill in a hospital associated with one or more previous
cases of Legionnaires’ disease, or yielded an isolate that was
indistinguishable (by monoclonal antibody subgrouping or by
molecular typing methods) from isolates obtained from the
hospital water system at about the same time.
prognosis A prediction of the probable course and outcome of a disease.
sentinel point Point in a water system that poses the highest risk from
infection (e.g. the furthest point from the water heater in a hot
water system, or the incoming water in a cold water system).
sequela A pathological condition resulting from a disease.
seroconversion Development of antibodies in blood serum as a result of
infection or immunization.
serogroup A subdivision of a species or subspecies distinguishable from
other strains therein on the basis of antigenic character testing
for recognizable antigens on the surface of the microorganism.
shot dose A brief, high-level treatment.
sporadic An isolated or unique case of a disease.
sullage Domestic wastewater other than that from toilets (also referred
to as greywater).
LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS