Published Date: 2010-07-18 23:50:00
Subject: PRO/EDR> Legionellosis - Spain (03): Barcelona, Pontiac fever
Archive Number: 20100718.2405
LEGIONELLOSIS - SPAIN (03): BARCELONA, PONTIAC FEVER
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Fri 16 Jul 2010
Source: ABC.es [in Spanish, trans. Corr.SB, edited]
A total of 43 Vallgorguina residents have been affected by an
outbreak of Pontiac fever, stated the mayor, Joan Mora.
To prevent the bacteria [_Legionella_ species] from spreading
further, the municipality has banned residents' sprinkler irrigation
(systems) for a few days, because it is suspected that the source of
the outbreak originated in irrigation systems located in the center
of town, according to the same sources.
The outbreak of Pontiac fever was 1st detected in the primary care
center of the town in early July 2010 and so far has affected 43
people in the center of Vallgorguina, none of whom had to be
hospitalized at this time.
The mayor has stated that "the last 3 cases detected today [16 Jul
2010] are people who had symptoms since last Mon 12 Jul 2010," and he
believes that the legionellosis outbreak is abating "because we are
not recording 4 or 5 cases daily as we were last week."
According to Mora, the technicians of the Department of Health of the
Government have already analyzed water from "wells, streams,
fountains and irrigation systems, and all results have come out
negative. We are waiting to receive the latest analysis from
yesterday [15 Jul 2010] of water from a tank that is used to water
the municipality flowers."
Pontiac fever is a type of very mild legionellosis, similar to a
winter flu, characterized by appearance of a general malaise and joint pain.
The mayor of the municipality is sorry for the alarm that followed an
anonymous letter sent by email to the media, which claimed that water
from the municipal water tank was infected.
Joan Mora has said that analysis of the town drinking water has
proven that it "meets all health requirements."
[Legionellosis is an infectious disease caused by a Gram-negative
bacillus of the genus _Legionella_, most commonly _Legionella
pneumophila_. Legionnaires' disease is the acute pneumonic form of
the disease. Pontiac fever is a non-pneumonic form of legionellosis
that is less severe than Legionnaires' disease, and develops from
hours to 2 days after initial infection with fever, malaise and
muscle aches. Symptoms resolve in 2 to 5 days without antibiotic
treatment. Attack rates are high; up to 95 percent of exposed persons
become ill. Unlike, legionnaires' diseases, there appear to be no
predisposing host conditions for Pontiac fever. Pontiac fever takes
its name from an outbreak in 1968 in Pontiac, Michigan.
Legionnaires' disease, and presumably Pontiac fever, is acquired by
inhalation of an infectious dose of aerosolized _Legionella_. Water
temperatures of 25-40 C (77-104 F) support the highest concentrations
of the organism in water storage tanks of plumbing systems.
Aerosolization of the contaminated warm water can occur in showers,
spa pools, sprays in groceries, fountains, and cooling towers. Why
some persons exposed to contaminated aerosols develop legionnaires'
disease and others develop Pontiac fever is unknown.
The diagnosis of Pontiac fever is usually made on the basis of
epidemiologic, clinical, serological, environmental microbiology
findings, and, in a variable portion of the affected people, the
development of antibodies to the bacterium isolated from the
environment. However, legionella species are commonly found in the
environment in the absence of illness, and legionella antibodies can
be non-specific. Urinary antigen for _L. pneumophila_ serogroup 1 is
uncommonly positive, and cultures are rarely positive for legionella
in patients with Pontiac fever. For a discussion of the pathogenesis
and diagnosis of Pontiac fever, see Edelstein PH. Urinary antigen
tests positive for Pontiac fever. Clin Infect Dis 2007; 44:2229-31.
Vallgorguina is a Catalan town with a population of about 2400, 50 km
northeast of Barcelona (<http://en.wikipedia.org/wiki/Vallgorguina>).
The HealthMap/ProMED-mail interactive map of Spain can be accessed at
<http://healthmap.org/r/01Dt>. - Mod.ML]