Fungal Diseases
Among the fungal diseases associated
with bird and bat droppings the two
most common are histoplasmosis and
cryptococcosis.
Histoplasmosis
Histoplasmosis is caused by a fungus
(Histoplasma capsulatum). The disease
is transmitted to humans by airborne
fungus spores from soil contaminated by
pigeon and starling droppings (as well
as from the droppings of other birds
and bats). The active and inactive
roosts of blackbirds, starlings,
grackles and cowbirds have
also been found to be
heavily contaminated with
fungus spores.
The soil under a roost usually
has been enriched by droppings for
three years or more for the disease
organism to reach significant levels.
Although almost always associated with
soil, the fungus has been found in
droppings alone, particularly those
from bats. Infection occurs when
spores, carried by the air, are
inhaled — especially after a roost has
been disturbed. Most infections are
mild and produce either no symptoms or
a minor influenza-like illness. On
occasion, the disease can cause high
fever, blood abnormalities, pneumonia
and even death. In some areas up to 80
percent of the population show evidence
of previous, usually asymptomatic
infection.
Dusts containing H. capsulatum spores
can be aerosolized during construction,
excavation, or demolition. Once
airborne, spores can be carried easily
by wind currents over long distances.
Such contaminated airborne dusts can
cause infections not only in persons at
a work site, but also in others nearby.
Such activities were suggested as the
cause of the three largest outbreaks of
histoplasmosis ever recorded. All three
outbreaks took place in Indianapolis,
Indiana. During the first outbreak, in
the fall of 1978 and spring of 1979, an
estimated 120,000 people were infected,
and 15 people died. The second outbreak,
in 1980, was similar to the
first in the number of people affected.
During the third outbreak, in 1988,
AIDS patients accounted for nearly 50%
of culture-proven cases.
The National Institutes of Health (NIH)
has reported a potentially blinding eye
condition — presumed ocular
histoplasmosis syndrome (OHS) — that
results from the fungus. NIH estimates
that 4 percent of those exposed to the
airborne organism are at risk of
developing OHS.
The soil in a stand of trees where
blackbirds have roosted for 3 or more
years should be suspected of being
contaminated by the fungus. Habitats of
pigeons and bats, and poultry houses
with dirt floors have also been found
contaminated by H. capsulatum.
Fresh bird droppings on surfaces such
as sidewalks and windowsills have not
been shown to present a health risk for
histoplasmosis because birds themselves
do not appear to be infected by H.
capsulatum. Rather, bird manure is
primarily a nutrient source for the
growth of H. capsulatum already present
in soil. Unlike birds, bats can become
infected with H. capsulatum and
consequently can excrete the organism
in their droppings.
Bats are associated with a few diseases
that affect people. The incidence of
histoplasmosis being
transmitted from bat
droppings to humans
occurs infrequently.
Large colonies of bats
do not normally inhabit
work areas. Bat
colonies are common in
undisturbed areas.
Nevertheless, fresh bat droppings
(unlike fresh bird dropping) can
contain the histoplasmosis fungus. Bat
droppings do not need to come into
contact with soil to be a source of the
disease.
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Anyone working at a job or present
near activities where material
contaminated with H. capsulatum
becomes airborne can develop
histoplasmosis if enough spores are
inhaled. After an exposure, how ill a
person becomes varies greatly and most
likely depends on the number of spores
inhaled and a person's age and
susceptibility to the disease. The
number of inhaled spores needed to
cause disease is unknown. Infants,
young children, and older persons, in
particular those with chronic lung
disease, are at increased risk for
developing symptomatic histoplasmosis.
Below is a partial list of occupations
and hobbies with risks for exposure to
H. capsulatum spores. Appropriate
exposure precautions should be taken
by these people and others whenever
contaminated soil, bat droppings, or
bird manure are disturbed:
• Bridge inspector or painter
• Chimney cleaner
• Construction worker
• Demolition worker
• Farmer
• Gardener
• Heating and air-conditioning system
installer or service person
• Microbiology laboratory worker
• Pest control worker
• Restorer of historic or abandoned
buildings
• Roofer and
• Spelunker (cave explorer).
If people who engage in these
activities develop flu-like symptoms
days or even weeks after disturbing
material that might be contaminated
with H. capsulatum, and the illness
worsens rather than subsides after a
few days, medical care should be
sought. The health care provider
should be informed about the potential
exposure.
Cryptococcosis
Cryptococcis neoformans (C. neoformans)
is found worldwide. Its main
habitats are debris around pigeon
roosts and soil contaminated with
decaying pigeon or chicken droppings.
It is generally accepted that the
organism enters the host by the
respiratory route in the form of a
dehydrated yeast or as spores.
Like histoplasmosis, most
cryptococcosis infections are mild and
occur without symptoms. Diffuse
pulmonary infection is often
asymptomatic and unrecognized. Persons
with weakened immune systems, however,
are more susceptible to symptomatic
infection. The generalized form of
cryptococcosis begins with a lung
infection and spreads to other areas
of the body, particularly the central
nervous system, and is usually fatal
if left untreated. The cutaneous
(skin) form is characterized by acnelike
skin eruptions or ulcers with
nodules just under the skin. The
cutaneous form is very rare, however,
without generalized (systemic)
disease. Unlike histoplasmosis, outbreaks
(multiple cases at a location)
of cryptococcosis infections have not
been documented.
Pigeon droppings appear to be the most
important source of the fungus C.
neoformans in the environment. The
fungus is typically found in
accumulations of droppings around
roosting and nesting sites, for
example, attics, cupolas, ledges and
water towers. It has been found in as
many as 84 percent of samples taken
from old roosts. Even when old and
dry, bird droppings can be a
significant source of
infection.
Other Associated Diseases
Other diseases carried or transmitted
by birds affect people to a lesser
degree. Psittacosis and toxoplasmosis
are normally mild in humans; however,
serious illness or death may occur
rarely. Pigeons and sparrows also have
been implicated (along with many other
species of birds) as sources of
encephalitis viruses transmitted by
mosquitoes.
Hope the masks were good ones, some good solutions to the original question, AOM mate, your title 'Fishing' reminded me of One of the old scaffs on the Byker wall (I wasnt there), but i heard he had a similar problem about getting gear fom 1 roof to another, he took a 'Fishing rod' to work. Cast the line over to the other roof, then attached the rope to the line etc.
