Laboratory Animal Allergy (LAA)
and Rodents
Note: Images used in
this presentation are for
educational, non profit
use ONLY.
Neil Grove
Division Of Laboratory Animal Medicine
University of North Carolina – Chapel Hill
What is LAA?
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LAA can be defined as allergic rhinitis
(inflammation and fluid production in
linings of nasal passages, sinuses, and
eyelids), asthma, and dermatological
symptoms that may result from exposure
to laboratory animals.
ILAR 2001
What are animal allergies?
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Animal-related allergies and asthma are
exaggerated reactions of the body’s
immune system to animal proteins, also
known as allergens. Sources of these
allergens include animal dander, scales,
fur, body wastes, and saliva.
NIOSH 1998
What about mice?
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The major mouse
allergen is Mus m 1, or
mouse urinary protein.
This allergen is found in
urine as well as in hair
follicles and dander. Mus
m 1 is produced in liver
cells, and males produce
approximately four times
more of it because gene
expression is
testosterone dependent.
ILAR 2001
What about rats?
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Rats are responsible
for symptoms in a
large portion of
people who have
laboratory-animal
allergy. The major
sources of ratallergen exposure
appear to be in the
urine and saliva of the
animal.
NRC 1997
Who is at risk?
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All animal handlers
appear to be at risk
for developing workrelated allergy
symptoms.
NIOSH 1998
Surprise, Surprise,
Surprise
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The estimated prevalence of allergic
symptoms in the general population of
regularly exposed animal-care workers
ranges from 10% to 44%. An estimated
10% of laboratory workers eventually
develop occupation-related asthma.
National Research Council 1997

In a survey of 5,641 workers from 137
animal facilities, 23% had allergic
symptoms related to laboratory animals.
Of the workers with symptoms:
82% had nasal or eye symptoms
46% had skin complaints
33% had asthma
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NIOSH 1998
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Who is at heightened risk?
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There is a correlation
between atopy (an
inherited, familial
tendency to develop
some form of allergy such
as hay fever, asthma,
eczema) and the potential
for developing LAA, and a
stronger positive
correlation between atopy
and development of
lower respiratory
symptoms (asthma).
CCAC
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Workers who had
symptoms or signs of
allergies before they were
employed as animal
handlers are more likely
to develop animalinduced asthma. Allergic
workers, particularly
those sensitized to
domestic animals such as
cats and dogs, are more
likely to develop
sensitivity to laboratory
animals and asthma than
non-allergic workers.
NIOSH 1998
Who is at heightened risk? Is it
Capt. Kirk or Commander Uhura?

Sorry Kirk, males are
more likely to be
atopic than females
(47% vs 37%) and so
more likely to develop
LAA.
CCAC
What about smokers?
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There have been some
connections made
between smoking and
LAA. According to the
Canadian Council on
Animal Care “…if a
smoker does develop
LAA, they are 1.5-3 times
as likely to get the lower
respiratory symptoms
(asthma).”
CCAC
How are we exposed to
allergens?
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The principle route of exposure to animal
allergens is inhalation of aeroallergens.
Direct skin and eye contact can also be a
common route of exposure and,
occasionally, ingestion. Percutaneous
exposures may result from animal bites,
needle punctures contaminated with
animal allergens, or allergen
contamination of wounds.
 ILAR 2001
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The principle route of exposure to animal
allergens is inhalation of aeroallergens.
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ILAR 2001
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So this means you are
breathing the allergen in.
As stated earlier, the
major mouse allergen is
Mus m 1, (mouse urinary
protein). If the primary
mouse allergen is found
in mouse urine, and the
primary means of
exposure is through
inhalation, do you think
that changing or dumping
urine soaked mouse
cages might be of
concern for allergen
exposure?
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What do some of the
hallways and animal
rooms smell like here on
a Monday morning or a
Tuesday after a holiday
weekend? How do some
of those cages smell in
cage wash on those
days? How much allergen
are you exposed to when
you open the cage? Do
you think your mask
should always be
covering your mouth and
nose and conformed to fit
properly?
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Direct skin and eye
contact  can also
be a common route
of exposure.
How are we exposed to allergens
on our skin?
Direct skin contact exposure
occurs when:
 An animal, or animal
waste, touches your skin
 Your skin comes in
contact with any object
that has been exposed to
animals (dirty gloves,
dirty bedding, dirty Tyvek)
How are our eyes exposed?

Any fluid (blood, urine, etc.) or exposed
solid materials (soiled bedding) in the eyes
can expose you to allergen, not to mention
expose you to any possible zoonotic
disease, or cause physical damage to the
eye itself.
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You can easily rub your eyes with your
gloves and expose yourself to allergens.
Anytime you touch anything that has
animal dander or dust on it, and then
touch your eyes, you expose yourself.
Example: Those of you that wear PAPR
(powered air-purifying respirators) - the
battery packs accumulate dust while you
are changing cages. After you have left a
room and are carrying that battery pack in
your bare hands, you will expose your
hands to allergen, and if you touch your
eyes, you’ve exposed them.
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Another example: Someone has placed a
dirty cage on top of a PPE bin and you
pick it up with your bare hands to move it
to the dirty cage cart, and then you touch
your eyes, you have now exposed your
eyes.
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Another example:
Changing the prefilter of a dump station
without PPE can
easily expose you.
Dirty pre-filters hold
extremely fine and
allergen-concentrated
dust particles that can
easily get in your
eyes, on your skin, on
your clothes, and can
easily be inhaled.
How are we exposed
percutaneously?
Percutaneous (through the skin) allergen exposure
is another concern.
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Bite wounds, needle sticks, and allergen
exposure to open wounds are all examples, and
pretty avoidable if caution is taken. Is it
important to be trained on how to handle
animals properly and always be alert while
handling them? Is it important to be very
cautious when handling sharp objects that have
been exposed to animals, to use the sharps
containers properly, and to never recap
needles? Should open wounds always be
properly dressed and not exposed?
What are the symptoms of
LAA?
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Symptoms of LAA are the result of the
release of biochemical mediators and the
generation of inflammation in the tissues
induced by IgE (immunoglobulin E)
response. The nature and intensity of the
symptoms are dependent on the level of
exposure to the laboratory animal allergen
by the individual. These symptoms can
range from mild skin reactions to severe
asthma.
ILAR 2001
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The most common
symptoms are related to
allergic reactions
involving the nose and
eyes and are known as
allergic rhinitis and
allergic conjunctivitis,
respectively. Nasal
symptoms include
congestion, runny nose,
sneezing, and itching;
ocular symptoms include
redness and itchy, watery
eyes. Up to 80% of
workers with LAA report
nasal symptoms.
ILAR 2001
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Skin reactions
include hives
(urticaria)

at the site of
contact with animal
urine or dander
and as a result of
scratches from
rough tails and
claws
ILAR 2001
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Other rashes
include
maculopapular
(measles-like)
rashes, which are
typically quite itchy
and occur in about
40% of
symptomatic
individuals
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Asthma may affect 20 to 30% of
symptomatic workers exposed to
laboratory animals. Symptoms of asthma
consist of cough, wheezing, and shortness
of breath. It is important to recognize that
symptoms related to laboratory animal
exposure may continue for several hours
after exposure to the animals ceases. In
addition, individuals may experience
symptoms of asthma when exercising and
when exposed to cold air, dust particles, or
strong odors.
ILAR 2001
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Systemic allergic reactions, known as
anaphylaxis, can occur (albeit rarely) as a result
of an animal bite or from puncture wounds (e.g.,
needles contaminated with animal proteins).
These reactions can manifest by generalized
itching, hives (urticaria), swelling (angioedema)
of the lips, eyes, and/or extremities, respiratory
distress due to edema of the larynx, hypotension
(shock), or acute asthma attacks. These
reactions are potentially fatal. Occasionally, a
milder form of systemic reaction can manifest in
which the allergic individual develops a
maculopapular rash or hives under protective
clothing as a result of a respiratory exposure to
laboratory animal allergens.
ILAR 2001
How long does it take to begin to develop
symptoms if I am allergic?
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Time from the onset of exposure to
development of symptoms is variable but
generally occurs within 3 yrs of beginning
employment. Approximately one third of
individuals will develop symptoms in the
first year and 70% within 3 yrs.
ILAR 2001
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In a study from the United Kingdom, the
mean duration of employment before the
onset of nasal symptoms was 214 days,
335 days for skin symptoms, and 365 for
the development of chest symptoms
(asthma).
ILAR 2001
How can we minimize
exposure?
Exposure can be minimized by:
 Protecting ourselves from exposure with
the proper use of PPE.
 Protecting ourselves from exposure
through good hygiene and housekeeping
Proper PPE use is essential!
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The main source of exposure to allergens
is through inhalation; therefore, respiratory
protection is the most important step that
can be taken to protect oneself from LAA.
Wearing a properly fitted respirator mask
of the appropriate type is essential to
ensure that allergens are not being
inhaled.
labanimal.com 2004
PPE
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The National Institutes of Health recommends
that employees with known allergies to animals
wear National Institute of Occupational Safety
and Health (NIOSH)–approved N-95 dust/mist
respirators. (these are our standard masks)
When properly fitted and worn correctly, these
masks filter out at least 95% of the particles that
are capable of transporting animal allergens.
labanimal.com 2004
PPE
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In cases when the N-95 respirator is not
sufficient, a PAPR can be provided.
("PAPR") devices, marketed as the air
helmet and air hat provide 100% HEPAfiltered air to control exposure and relieve
symptoms for sensitized workers”
ILAR 2001
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Protection of skin and hair from contact
with animal allergens through the use of
protective clothing is an effective means of
prevention. Use of dedicated clothing
when in the facility also helps prevent the
distribution of allergens outside of the
facility into offices or public areas, or to the
employee's home.
labanimal.com 2004
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For example, while in the animal facility
one may wear a uniform or scrubs rather
than street clothes, and a lab coat or
disposable garments that can be shed at
the facility door. Hair bonnets, shoe
covers, and gloves are helpful in
protecting contamination of skin and hair
and, when shed at the facility door,
prevent the dispersal of allergens to the
outside. Eye protection can also be
important to prevent exposure to allergens
and the symptoms of itchy, watery eyes.
labanimal.com 2004
Protection from exposure through
good hygiene is essential.
Hygiene  Good personal hygiene through frequent
glove changing and hand washing can
limit hand-to-nose or hand-to-mouth
transmission. (and hand to eye)
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labanimal.com 2004
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If you use a PAPR, the filter must be monitored
and changed frequently. The battery pack
should be cleaned and kept dust free (it can
expose you), and the face shield should be
cleaned frequently and changed when
necessary.
As stated when addressing PPE, scrubs should
be worn whenever possible and taken off as
soon as possible after working with animals.
Protection from exposure with good
housekeeping is very important.
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Animal rooms should be frequently cleaned using wet
methods. Left in the room environment, aeroallergens
will eventually either settle out onto horizontal surfaces
or adhere to hard surfaces. These settled and adhered
particles can become secondary sources of exposure,
especially in the presence of poor cleaning habits or
inappropriate cleaning methods. Dry sweeping, for
example, can be a significant source of exposure
because re-suspended aeroallergens are introduced into
the worker's breathing zone only feet away from the
point of emission. Compliance with accreditation
agencies and concerns for animal health usually
promote satisfactory cleanliness within the animal
facility.
ILAR 2001
Precautions/Prevention
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Is it clear now why we stress the following?:
When changing cages, scrubs must be worn,
and not just street clothes under coveralls
Limit the number of people who wear scrubs out
of the animal facility
Keep your work shoes at work
Safety glasses, safety glasses, safety glasses
Frequently sanitize floors, wipe down racks, and
wipe off shelves above sinks
Recommendations
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If you have any of the symptoms
mentioned in this training, report it to your
supervisor. The greater the exposure you
experience, the more severe your
symptoms will become. It is essential that
the allergy is caught early. “With early
identification of allergic reactions to
animals and appropriate treatment, most
people can avoid further injury or the
development of asthma” NIH Pamphlet
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“Exposure to airborne allergens may first
result in nasal, eye, and throat irritation as
well as skin hives. As many as 50% of
workers with these symptoms go on to
develop asthma symptoms such as
recurrent episodes of coughing, wheezing,
chest tightness, and difficult breathing.
Nasal symptoms usually develop first,
occupational asthma without nasal
symptoms is uncommon.” NIOSH 1998
Wash your hands, wash your hands, wash
your hands!
 They touch everything and then they touch
you – often without thinking you end up
touching your eyes, mouth, and skin.
Keep those hands clean.
 Do not touch any part of your exposed
body with dirty gloves. Touching your
eyes, nose, mouth, or exposed skin with
dirty gloves exposes you.
Report any ventilation issues in your animal
rooms immediately
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An essential element of reducing exposure
to aeroallergens is proper ventilation and
air flow.
Keep your environment clean
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Dirty cages and bedding are sources of
allergens – get rid of them – dirty cages
should not stay in the animal rooms for
any longer than they have to and dirty
bedding should not be on the floor, carts,
racks or other surfaces.
 If
you are in a room that has a
workbench, use it. They are an
excellent means of protecting you
from allergens.
You have PPE – Use it – and then take it off
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Keep allergens off your skin, out of your lungs,
and out of your eyes.
Take off your scrubs at lunch time. They have
been exposed to allergens. Leaving them on
extends your exposure, especially while you are
eating.
Common sense rules. If it touches or is exposed
to animals or animal materials in any way, it can
expose you to allergens.
Conclusion
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It is up to you to
protect yourself from
allergen exposure by
following procedures,
reporting symptoms,
and asking questions.
References
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ILAR 2001 – ILAR Journal 42 (1) viewed at:
http://dels.nas.edu/ilar_n/ilarjournal/42_1/
NIOSH 1998 – NIOSH ALERT Preventing Asthma in Animal
Handlers January, 1998
National Research Council 1997 – “Occupational Health and Safety
in the Care and Use of Research Animals” National Academy
Press, 1997.
labanimal.com 2004
“Laboratory Animal Allergies: Overview of
Causation and Prevention” viewed at:
http://www.labanimal.com/laban/journal/v33/n10/full/laban1104-25.html
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NIH Pamphlet NIH Pamphlet “Allergies To Laboratory Animals – A
Significant Health Risk”
CCAC (Canadian Council on Animal Care
http://www.ccac.ca/en/CCAC_Programs/ETCC/Module12E/module1
2-16.html#top
Questions???????
1.
Are workers who have been sensitized to dogs and cats more or less
likely to develop sensitivity to lab animals?
2.
What is the principle route of exposure to animal allergens?
The primary mouse allergen Mus m 1 is found in what substances?
Bite wounds and needle sticks are examples of __________ allergen
exposure.
Symptoms of LAA are the result of the release of biochemical mediators
and the generation of inflammation in the tissues induced by
____________response.
Up to ______ % of workers with LAA report nasal symptoms.
Another name for hives is _________.
Measle-like or ________ rashes, are typically quite itchy and occur in
about 40% of symptomatic individuals.
Systemic allergic reactions, known as ___________, can occur as a
result of an animal bite or from puncture wounds.
These masks filter out at least 95% of the particles that are capable of
transporting animal allergens ___________.
3.
4.
5.
6.
7.
8.
9.
10.
Questions??????
11.
12.
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15.
16.
17.
18.
19.
20.
PAPR stands for _______.
_______ can be a significant source of exposure because re-suspended
aeroallergens are introduced into the worker's breathing zone.
Occupational asthma without _________ is uncommon.
____________ can be defined as allergic rhinitis, asthma, and
dermatological symptoms that may result from exposure to laboratory
animals.
True or false: Female mice produce four times more of the Mus m 1
allergen.
Who is at risk for developing animal related allergy symptoms?
True or false: Changing a dump station pre-filter poses no significant risk
for allergen exposure.
Generally, the onset of allergic symptoms occurs within the first ____
years of employment.
It is important to leave your blues (scrubs) in the animal facility
because____________
Ultimately, who is responsible for protecting you from allergen exposure?
Credit and Disclaimer
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The vast majority of this presentation was
created while I was an employee of
Priority One Services (POS) at the
National Institute of Environmental Health
Sciences (NIEHS). Thus, both groups
deserve credit for supporting this work.
However, views expressed in this
presentation are those of the author, and
do not necessarily reflect those of POS,
NIEHS, or UNC DLAM.