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symptoms had lower single-breath, carbon-monoxide-diffusing capacities than did
controls.
The suite was located directly beneath the kitchen of a cafeteria and had been
subjected to. a series of "floods" from drainage 1ines, including a drain from the
cafeteria dishwasher. Numerous microorganisms, including Acanthamoeba polyphaga and
Thermoactinomyces vulgaris, were isolated from the office and the HVAC system.
However, attempts through serologic testing to link these agents specifically with
illness in individuals produced inconclusive results. Epidemiologic evidence
suggested that environmental contaminants present in the water drainage were asso-
ciated with illness. All workers were removed from the affected office; the office
was completely refurbished and is presently being reoccupied. There has been no
1 recurrence of illness.
MMWR Editorial Note: Outbreaks of hypersensitivity pneumonitis (HP), humidifier
fever, and similar syndromes among office workers have been described since 1970.
Symptoms include headache, fatigue, muscle aches, chills, and fever. Manifestations
of pulmonary disease, such as chest tightness, coughing, and wheezing, were also
observed. These outbreaks have been attributed to thermophi 1 ic actinomycetes,
nonpathogenic amoeba, several fungi, and endotoxins. Sources of microbial contamina-
tion included humidifiers, air washers, and contaminated filters in air-handling
units.
-yr Since October 1981, the National Institute for Occupational Safety and Health has
conducted environmental studies in six large multistory office buildings in which HP-
like syndromes were reported or were alleged to occur, including those reported here.
Results of these studies suggest that moisture incursion into occupied spaces and
into HVAC system components may have been common to these outbreaks. Engineering
measures thought to prevent the occurrence of such outbreaks are straightforward,
feasible, and inexpensive. They include: (1) promptly and permanently repairing all
external and internal leaks; (2) maintaining relative humidity below 70% in occupied
spaces and in low-air-velocity plenums (at higher levels of humidity, the germination
and proliferation of fungal spores is enhanced); (3) preventing the accumulation of
stagnant water under cooling-deck coils of air-handling units through inclination and
continuous drainage of drain pans; (4) using steam, rather than recirculated water,
as a water source for humidifiers in HVAC systems; however, such steam sources should
not be contaminated with volatile amines; (5) replacing filters in air-handling units
at regular intervals (these should have at least a moderate efficiency rating [50% or
more] as measured by the atmospheric-dust spot test and should be of the extended-
surface type; pref i l ter s [eg, roll type] should be used before air passage over the
higher-efficiency filters); (6) discarding, rather than disinfecting, carpets,
upholstery, ceiling tiles, and other porous furnishings that are grossly contami-
nated; (7) providing outdoor air into ventilation systems at minimum rates per
occupant of at least 20 cubic feet per minute in areas where occupants are smoking
and at least 5 cubic feet per minute in nonsmoking areas. These activities should be
considered in on-going preventive-maintenance programs.
-4
INFLUENZA -- SOUTHERN HEMISPHERE, ASIA, THE TROPICS, 1984
The following article first appeared in the Centers for Disease Control (CDC)
publication, Morbidity and Mortality Weekly Report, Vol. 33/No. 36, September 14,
1984.
Influenza usually occurs from about April through September in the Southern
Hemisphere and often occurs throughout the year in the tropics. Surveillance in
these regions may, therefore, identify strains that subsequently appear in the
Northern Hemisphere.
