Control of Health Hazards Associated with Bird
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Public Employees Occupational
Safety and Health Program
Division of Epidemiology, Environmental and Occupational Health
Christine Todd Whitman Christine M. Grant, JD, MBA
Governor Commissioner April, 2000
Control of Health Hazards Associated with Bird
and Bat Droppings
Special points of Health Risks
interest:
• Disease Association Large populations of roosting
birds may present a disease
• Recognition risk. The most serious health
risks arise from disease
• Evaluation organisms that grow in the
nutrient-rich accumulations of
• Hazard Control bird droppings, feathers and
debris under a roost —
• Recommendations particularly if roosts have been location. In one New Jersey
active for years. In addition, worksite, accumulated manure
• Further Information was found in a stair well
insects that live on birds or
their droppings may become a leading to the basement.
problem when the infested birds Local newspapers reported
leave roosts or nests. These that a city hall building
insects can invade buildings and was “taken over” by pigeons
bite or irritate people. that had deposited several
inches of manure on the
This bulletin discusses the window ledges. At a bridge
health risks and control of the commission, employees
risk of several of the fungal complained to the PEOSH
diseases associated with bird Program that their booths
and bat droppings and methods of were covered in pigeon
controlling these risks. droppings. Maintenance
engineers at a university
The PEOSH Program has campus were concerned about
evaluated several work bird droppings near a
sites where employees ventilation system located
were concerned about on the roof of one of the
health hazards from buildings. Furthermore,
accumulated pigeon several building attics were
droppings. The common evaluated because of
denominator in these employee concerns with bird
PEOSH investigations has manure accumulations.
been the presence of roosting
pigeons in an undisturbed
Page 1the fall of 1978 and spring of 1979, an
Fungal Diseases estimated 120,000 people were infected,
and 15 people died. The second out-
Among the fungal diseases associated break, in 1980, was similar to the
with bird and bat droppings the two first in the number of people affected.
most common are histoplasmosis and During the third outbreak, in 1988,
cryptococcosis. AIDS patients accounted for nearly 50%
of culture-proven cases.
Histoplasmosis
The National Institutes of Health (NIH)
Histoplasmosis is caused by a fungus has reported a potentially blinding eye
condition — presumed ocular
(Histoplasma capsulatum). The disease
is transmitted to humans by airborne histoplasmosis syndrome (OHS) — that
fungus spores from soil contaminated by results from the fungus. NIH estimates
pigeon and starling droppings (as well that 4 percent of those exposed to the
as from the droppings of other birds airborne organism are at risk of
and bats). The active and inactive developing OHS.
roosts of blackbirds, starlings,
grackles and cowbirds have The soil in a stand of trees where
also been found to be blackbirds have roosted for 3 or more
heavily contaminated with years should be suspected of being
fungus spores. contaminated by the fungus. Habitats of
pigeons and bats, and poultry houses
The soil under a roost usually with dirt floors have also been found
has been enriched by droppings for contaminated by H. capsulatum.
three years or more for the disease
organism to reach significant levels. Fresh bird droppings on surfaces such
Although almost always associated with as sidewalks and windowsills have not
soil, the fungus has been found in been shown to present a health risk for
droppings alone, particularly those histoplasmosis because birds themselves
from bats. Infection occurs when do not appear to be infected by H.
spores, carried by the air, are capsulatum. Rather, bird manure is
inhaled — especially after a roost has primarily a nutrient source for the
been disturbed. Most infections are growth of H. capsulatum already present
mild and produce either no symptoms or in soil. Unlike birds, bats can become
a minor influenza-like illness. On infected with H. capsulatum and
occasion, the disease can cause high consequently can excrete the organism
fever, blood abnormalities, pneumonia in their droppings.
and even death. In some areas up to 80
percent of the population show evidence Bats are associated with a few diseases
of previous, usually asymptomatic that affect people. The incidence of
infection. histoplasmosis being
transmitted from bat
droppings to humans
Dusts containing H. capsulatum spores
can be aerosolized during construction, occurs infrequently.
excavation, or demolition. Once Large colonies of bats
airborne, spores can be carried easily do not normally inhabit
by wind currents over long distances. work areas. Bat
Such contaminated airborne dusts can colonies are common in
cause infections not only in persons at undisturbed areas.
a work site, but also in others nearby. Nevertheless, fresh bat droppings
Such activities were suggested as the (unlike fresh bird dropping) can
cause of the three largest outbreaks of contain the histoplasmosis fungus. Bat
histoplasmosis ever recorded. All three droppings do not need to come into
outbreaks took place in Indianapolis, contact with soil to be a source of the
Indiana. During the first outbreak, in disease.
Page 2Anyone working at a job or present roosts and soil contaminated with
near activities where material decaying pigeon or chicken droppings.
contaminated with H. capsulatum It is generally accepted that the
becomes airborne can develop organism enters the host by the
histoplasmosis if enough spores are respiratory route in the form of a
inhaled. After an exposure, how ill a dehydrated yeast or as spores.
person becomes varies greatly and most
likely depends on the number of spores Like histoplasmosis, most
inhaled and a person's age and cryptococcosis infections are mild and
susceptibility to the disease. The occur without symptoms. Diffuse
number of inhaled spores needed to pulmonary infection is often
cause disease is unknown. Infants, asymptomatic and unrecognized. Persons
young children, and older persons, in with weakened immune systems, however,
particular those with chronic lung are more susceptible to symptomatic
disease, are at increased risk for infection. The generalized form of
developing symptomatic histoplasmosis. cryptococcosis begins with a lung
infection and spreads to other areas
Below is a partial list of occupations of the body, particularly the central
and hobbies with risks for exposure to nervous system, and is usually fatal
H. capsulatum spores. Appropriate if left untreated. The cutaneous
exposure precautions should be taken (skin) form is characterized by acne-
by these people and others whenever like skin eruptions or ulcers with
contaminated soil, bat droppings, or nodules just under the skin. The
bird manure are disturbed: cutaneous form is very rare, however,
without generalized (systemic)
• Bridge inspector or painter disease. Unlike histoplasmosis, out-
• Chimney cleaner breaks (multiple cases at a location)
• Construction worker of cryptococcosis infections have not
• Demolition worker been documented.
• Farmer
• Gardener Pigeon droppings appear to be the most
• Heating and air-conditioning system important source of the fungus C.
installer or service person neoformans in the environment. The
• Microbiology laboratory worker fungus is typically found in
• Pest control worker accumulations of droppings around
• Restorer of historic or abandoned roosting and nesting sites, for
buildings example, attics, cupolas, ledges and
• Roofer and water towers. It has been found in as
• Spelunker (cave explorer). many as 84 percent of samples taken
from old roosts. Even when old and
If people who engage in these dry, bird droppings can be a
activities develop flu-like symptoms significant source of
days or even weeks after disturbing infection.
material that might be contaminated
with H. capsulatum, and the illness Other Associated Diseases
worsens rather than subsides after a
few days, medical care should be
sought. The health care provider Other diseases carried or transmitted
should be informed about the potential by birds affect people to a lesser
exposure. degree. Psittacosis and toxoplasmosis
are normally mild in humans; however,
serious illness or death may occur
Cryptococcosis rarely. Pigeons and sparrows also have
been implicated (along with many other
Cryptococcis neoformans (C. neofor- species of birds) as sources of
mans) is found worldwide. Its main encephalitis viruses transmitted by
habitats are debris around pigeon mosquitoes.
Page 3Rabies, another viral disease, is a require some occasional maintenance to
dangerous, fatal disease, but only clear nesting material or other debris
about 5 percent of bats submitted for from the wires.
testing are infected with the rabies
virus. However, there is concern about Live trapping of birds to relocate
the risk of rabies transmission them is seldom effective when traps
following contact with bats. If an are put in a roosting site, but this
injured or ill bat is found in or method can be effective when used in a
around a structure, it should be feeding area. Shooting birds, using
removed. Because most bats will try to contact poisons, and baiting with
bite when handled, they should be poisoned food should be used as last
picked up with tongs or a shovel. (If resorts and should only be done by
you are uncomfortable removing a bat, qualified pest control specialists.
contact your local animal control Using such methods to kill nuisance
officer.) If a bat has bitten or birds may also require a special
scratched someone, capture the bat permit.
without touching it with
your hands and without If a colony of bats or a flock of
crushing its head. If birds is allowed to live in a building
the bat is dead, refrig- or a stand of trees, their manure will
erate it (DO NOT freeze) accumulate and create a health risk
and then contact your for anyone who enters the roosting
local health department immediately area and disturbs the material. Once a
for instructions. roosting site has been discovered in a
building, exclusion plans should be
Hazard Control made, and the extent of contamination
should be determined.
To reduce the health risks associated
Areas known or suspected of being
with the removal of droppings various
contaminated by H. capsulatum, such as
methods have been developed. When an
bird roosts, attics, or even entire
accumulation of bat or bird manure is
buildings that contain accumulations
discovered in a building, removing the
of bat or bird manure, should be
material is not always the next step.
posted with signs warning of the
Simply leaving the material alone if
health risk. Each sign should provide
it is in a location where no human
the name and telephone number of a
activity is likely may be the best
person to be contacted if there are
course of action. This is not always
questions about the area. In some
possible, of course, and, if the
situations, a fence may need to be
potential for human exposure exists,
built around a property or locks put
methods of safely controlling the
on attic doors to prevent unsuspecting
risks during removal must be
or unprotected individuals from
undertaken.
entering.
Nontoxic, chemical bird repellents are
available as liquids, aerosols, and Communicating Health Risks to
nondrying films and pastes.
Disadvantages of these anti-roosting Workers
materials are that some are messy and
none are permanent. Even the most Before an activity is started that may
effective ones require periodic disturb any material that might be
reapplication. More permanent contaminated by fungal spores, workers
repellents include mechanical should be informed in writing of the
anti-roosting systems consisting of personal risk factors that increase an
angled and porcupine wires made of individual's chances of developing
stainless steel. These systems may fungal diseases. This written
Page 4communication should include a material in a short
warning that individuals with period. Using long,
weakened immune systems are large-diameter hoses can
at the greatest risk of also remove contaminated
developing severe and material located several
disseminated fungal disease if stories above the waste
they become infected. These hopper. This advantage
people should seek advice from eliminates the risk of
their health care provider. dust exposure that can
happen when bags tear
accidentally or
Controlling Aerosolized containers break during
their transfer to the
Dust When Removing Bat or ground.
Bird Manure from a
Building Air sampling, surface
sampling, or the use of
The best way to prevent any other method
exposure to fungus spores is to intended to confirm that no infectious
avoid situations where material that agents remain following removal of bat
might be contaminated can become or bird manure is unnecessary in most
aerosolized and subsequently cases. However, before a removal
inhaled. A brief inhalation exposure activity is considered finished, the
to highly contaminated dust may be cleaned area should be visually
all that is needed to cause inspected to ensure that no residual
infection and subsequent development dust or debris remains.
of fungal disease. Therefore, work
practices and dust control measures
that eliminate or reduce dust Disinfecting Contaminated
generation during the removal of bat Material
or bird manure from a building will
also reduce risks of infection and
subsequent development of disease. Disinfectants have occasionally been
For example, before shoveling or used to treat contaminated soil and
sweeping dry, dusty material, it accumulations of bat manure when
should be made wet with a water removal was impractical or as a
spray to reduce the amount of dust precaution before a removal process
aerosolized during the activity. was started. Formaldehyde solutions
Adding a surfactant or wetting agent are the only disinfectants proven to
to the water might further reduce be effective for decontaminating soil
the amount of aerosolized dust. Once containing fungal spores. Because of
the material is wetted, it can be the potentially serious health hazards
collected in double, heavy-duty associated with formaldehyde
plastic bags, a 55-gallon drum, or exposures, this chemical should be
some other secure container for handled only by persons who know how
immediate disposal. to apply it safely. Any material that
might be contaminated with fungal
An alternative method is to use an spores that is removed from a work
industrial vacuum cleaner with a site should be disposed of or
high-efficiency (HEPA) filter to bag decontaminated properly and safely and
contaminated material. Truck-mounted not merely moved to another area where
or trailer-mounted vacuum systems it could still be a health hazard.
are recommended for buildings with Before an activity is started, the
large accumulations of bat or bird quantity of material to be removed
manure. These high-volume systems should be estimated. (If the
can remove tons of contaminated approximate volume of dry bat or bird
Page 5manure in a building is known, the still wearing a respirator,
approximate weight can be calculated remove protective clothing
using a conversion factor of 40 pounds and place it in a plastic
per cubic foot.) Requirements bag
established by local and state • Wash or shower at the work
authorities for the removal, site after clean-up
transportation, and disposal of • Check with local government
contaminated material should be agencies to verify that
followed. Arrangements should be made disposal of the waste is
with a landfill operator concerning permissible through
the quantity of material to be standard trash pickup
disposed of, the dates when the • Modify the structure to
material will be delivered, and the prevent birds or bats from
disposal location. If local or state reestablishing the roost.
landfill regulations define material
contaminated with fungal spores to be
infectious waste, incineration or Wearing Personal Protective
another decontamination method may
also be required.
Equipment
Because work practices and dust control
measures to reduce worker exposures to
Removal and Cleanup of Bird and fungal spores have not been fully
Bat Droppings evaluated, using personal protective
equipment is still necessary during
If there is a small accumulation of some activities. During removal of an
droppings from a few birds or bats, it accumulation of bat or bird manure from
can be cleaned up with soap and water. an enclosed area such as an attic, dust
If large quantities of bird or bat control measures should be used, but
droppings are present, contact an wearing a NIOSH-approved respirator and
environmental engineering consultant other items of personal protective
for advice. Workers should follow equipment is also recommended to reduce
certain precautions to minimize risk further the risk of fungal spore
from disease organisms in the exposure.
droppings:
If employers provide employees with
• The cleanup should be done personal protective equipment and
by healthy individuals respirators, the employer must comply
• Wear an appropriate with the provisions of the PEOSH
respirator that can Standards for these devices, 29 CFR
filter particles as small 1910.132 and 29 CFR 1910.134
as 0.3 microns respectively.
• Wear disposable protective
gloves, hat, coveralls and Other Resources
boots
This information bulletin provides
• During the cleanup, seal
an overview of some of the health haz-
heating and cooling air
ards associated with pigeon and bat
ducts or shut the system
droppings and the personal
down
protective equipment recommended
• Moisten the droppings with
for removing the material. For
a light mist of water to
further information on these
keep dust and spores from
topics please consult the
becoming airborne
resources listed below.
• Put droppings into sealed
Information used in
plastic garbage bags
this bulletin was
• When finished and while
obtained from US
Page 6Department of Human Services, Public
Health Service documents. These
include the National Institution for
Occupational Safety and Health (NIOSH)
and the Center for Disease Control and
Prevention (CDC).
FOR FURTHER INFORMATION CONTACT:
New Jersey Department of Health and
Senior Services
Public Employees Occupational Safety
and Health (PEOSH) Program
P.O. Box 360, 7th Floor
Trenton, NJ 08625-0360
(609) 984-1863
Http://www.state.nj.us/health/eoh/
peoshweb
PUBLICATIONS:
Histoplasmosis: Protecting
Workers At Risk
U.S. Department of Health and Human
Services
Public Health Service
Centers for Disease Control and
Prevention
National Institute for Occupational
Safety and Health
National Center for Infectious Disease
DHHS (NIOSH) Publication Number 97-146
Managing Health Hazards
Associated with Bird and Bat
Excrement
U.S. Army Center for Health Promotion
and Preventive Medicine
USAEHA TG No. 142
December 1992
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