Assessment and treatment of laboratory animal allergy. ILAR 42 (1):
055.
The time that it takes to develop LAA varies from <30 days to >3-4
years, averaging 214 days to develop rhinitis and 1 year to develop chest
and skin symptoms. Confirmation of the diagnosis requires that specific
IgE antibodies to lab animal allergens be confirmed. This is complicated
by the fact that the test allergens are not standardized. Many are prepared
from dander rather than urine, and this can cause false negative tests.
Clinical assessment is easiest with the skin prick test, in which a drop
of extract is placed on the skin, which is then pricked with a needle.
A wheal and flare will develop in 10-15 minutes in the test site and the
positive control (histamine) site if the patient is allergic. Intradermal
skin testing is rarely performed, and usually when a patient has a negative
skin prick test but is still suspected to be allergic. The intradermal
injection of antigen has a risk for anaphylaxis, and should only be performed
by physicians with special training.
In vitro testing includes radioallergosorbent (RAST) testing or ELISA testing. RAST testing by definition requires radioactive substances, and ELISA is therefore more common. Both detect specific IgE antibodies. The CAP-RAST (term not defined) is a newer and more sensitive in vitro test. In general, skin testing is more sensitive than in vitro testing, which can have false positives (from high total serum IgE) and false negatives (from binding of a different antibody isotype than IgE).
Assessment of lung function is required in patients who have lower respiratory symptoms. Spirometry is the gold standard and yields forced expiratory volume in 1 sec (FEV1), forced vital capacity, and maximum mid-expiratory flow rate (FEF25-75). The best way to make the diagnosis of asthma is to measure the person's peak expiratory flow rate (PEFR) several times during and after work; care must taken that the nefarious person does not purposely control the outcome of this "workplace challenge". Occasionally, a test called nonspecific bronchial hyper-responsiveness is performed, in which the patient inhales methacholine or histamine in titrated doses until there is a 20% decrease in pulmonary function. Patients with both specific IgE antibodies to lab animal allergens and a positive nonspecific hyper-responsiveness are more likely to have asthma. The gold standard test for confirming a diagnosis of asthma due to lab animals is the bronchoprovocation challenge. In this test the patient undergoes spirometry every 10-15 minutes after inhaling first saline, then titrated doses of the allergen. A positive test is a decrease in lung function by 20-25% up to 12 hours after the challenge. This last test must be performed in specially-equipped centers by experienced physicians.
Treatment consists first of exposure reduction and avoidance, which includes worker education and personal protective equipment such as dust-mist masks (although they remove only 98% of the rodent urinary allergens) or respirators (better for those with symptomatic disease). These do not prevent progression of the disease, and are not a substitute for removal of the symptomatic individual from exposure.
Pharmacologic management includes first antihistamines taken prior to
going to work to control pruritis and rhinitis but not nasal congestion.
Mast cell stabilizers (cromolyn and nedrocrimil) prevent mast cell degranulation
and are also taken prior to going to work. They do not work to treat acute
symptoms. Those with asthma should carry short-acting beta-receptor agonist
drugs in an inhaler to combat acute symptoms. Those with chronic asthma
often add inhaled corticosteroids. In a few individuals, immunotherapy
(giving allergenic extracts) has been tried. It is most applicable to those
with only intermittent exposure and has not yet been shown to protect against
progression of symptoms.
No questions
Laboratory Animal Allergens. ILAR 42 (1): 012.
Currently, the prevalence of laboratory animal allergy in animal workers
is estimated to be 21%. While allergens have been identified for many species,
reactions to mice and rat allergens are the most common.
Most allergens are small, acidic glycoproteins. Many are members of
a superfamily of extracellular proteins called lipocalins.
The production of some allergens appear to be androgen dependent.
Most allergens travel through the environment on small particles that
can stay airborne for extended periods and that can travel to the level
of the small airways. Animal allergens can be carried for large distances
in animal facilities. Therefore, while allergies are most common in individuals
with intense animal exposure (handlers involved in cage cleaning and feeding),
workers with no direct animal contact can also be affected.
Some identified animal allergens include the following:
in Mus musculus:
Mus m 1 (prealbumin) in hair, dander, and urine
Mus m 2 in hair, and dander
Albumin in serum
in Rattus norvegicus:
Rat n 1A/Rat n 1 B (alpha 2u-globin) in hair, dander, urine, and saliva
Albumin in serum
in Cavia porcellus:
Cav p 1 in hair, dander, and urine
Cav p 2 in hair, dander, and urine
in Oryctolagus cuniculus:
Ory c 1 in hair, dander, and saliva
Ory c2 in hair, dander, and urine
in Felis domesticus:
Fel d 1 in hair, dander, and saliva
albumin in serum
in Canis familiaris:
Can f 1 in hair, dander, and saliva
Can f 2 in hair, dander, and salive
albumin in serum
No questions
Mechanism and Epidemiology of Laboratory Animal Allergy. ILAR
42 (1): 004.
The National Institute of Occupational Safety and Health has formally
recognized laboratory animal allergy (LAA) as an occupational hazard since
1989. The overall incidence of LAA is estimated at approximately 15% and
the incidence of asthma due to LAA is estimated to be approximately 2%
(although these numbers vary between different studies). Virtually any
laboratory animal can cause occupational allergy, although guinea pigs,
mice, rats, cats, dogs, and non-human primates are most commonly involved
(rabbits are conspicuously absent...this observation is from my own personal
experience!!!).
Exposure to a variety of protein and glycoprotein antigens occurs mostly
through inhalation, but can occur through skin contact. Therefore, symptoms
range from mild skin reactions (hives, maculopapular rashes) to asthma.
However, the most common symptoms involve the nose and eyes (congestion,
runny nose, watery eyes, sneezing, itching of nose and eyes = allergic
rhinitis/conjunctivitis). Rarely does anaphylaxis occur. Time from onset
of exposure (sensitization) 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
years (although this is variable between studies). Proposed risk factors
include the level of exposure to laboratory animal allergens, coexisting
allergies (indicating a genetic predisposition, although the defect has
not been identified), and smoking tobacco. However, the last two factors
are still controversial.
Allergies are classified as immediate hypersensitivity reactions, or
type 1 reactions, and involve production of IgE antibodies. The mechanism
of sensitization and development of obvious clinical symptoms is complex.
To summarize, inhaled allergens are internalized by antigen-presenting
cells (dendritic cells, monocytes, alveolar macrophages) and after processing,
are presented to T cells by MHC Class II molecules. Under the appropriate
cytokine conditions (IL-4), these T cells develop into Th2-type CD4+ T
cells (elaborate IL-4, IL-5, IL-9, IL-10, IL-13). IL-4 and IL-13 are involved
in the production of IgE antibodies, while IL-5 results in maturation and
recruitment of eosinophils into tissues (Eosinophils are the hallmark of
allergic inflammation and are the key effector cell in the airway inflammation
that occurs in asthma). Circulating antigen-specific IgE binds to the surface
of mast cells and basophils, and after interactions with the specific allergen
(rat and mouse urinary proteins, for example), histamine is released, and
other vasoactive molecules, such as leukotrienes and prostaglandins, are
generated. Chemokines, such as RANTES and eotaxin, are released and attract
other inflammatory cells into the tissues. These cells and molecules then
contribute to the development of allergic symptoms and disease states,
such as asthma.
Questions:
1. What immunopathologic mechanism does LAA belong to?
2. What is probably the most important effector cell in the development
of airway inflammation that occurs during allergic asthma?
Answers:
1. Type 1 Reactions--immediate type hypersensitivity; mediated by substances
produced by basophils and mast cells; antibodies are usually of the IgE
class; anaphylaxis is of this type.
2. eosinophils
Controlling exposure to laboratory animal allergens. ILAR 42
(1): 017.
This article provides a comprehensive review of exposure control options.
A combination of engineering, administrative and personal protective equipment
(PPE) are integral to management of a lab animal facility. No clearly established
threshold for allergen exposure exists. The conventional hierarchy for
exposure control includes engineering control, administrative control,
and PPE. Virtually any material in contact with lab animals can be contaminated
will allergens. Particle size varies considerably, but lab animal allergens
are potent sensitizers in even nanogram amounts. Inhalation is the principle
route of exposure, although animal bites form the greatest risk of anaphylaxis.
Allergen monitoring is by traditional particulate sampling. A calibrated sampling pump moves air through filters which are then eluted and assayed using the radioallergosorbant inhibition test or the enzyme-linked immunosorbent assay. The lack of standardized antibody and test protocols make study comparisons difficult. Exposure risks are nearly 10X higher for certain tasks such as cage cleaning. Vectors for exposure include air currents, contaminated people and equipment.
Engineering controls are preferred because they do not rely on human intervention. Source control (capture and removal) is often the most efficient and cost effective control method. Engineering controls involve material substitution, process change, isolation and ventilation. Some mouse strains such as the C57BL/6J produce higher levels of allergens than others. Researchers have found a 57% reduction in aeroallergens by switching from woodchips to corncob bedding. Automation through robotics (cagewash) can reduce aeroallergens but initial capitol costs are large. Other process changes include use of vacuum clippers, HEPA filtered vacuum cleaners, pneumatic waste disposal and bedding dispensers. Allergenic proteins are water soluble and wet cleaning methods should be used. An evaluation showed no significant differences between manual dumping of bedding and vacuum removal because it took twice as long for workers to vacuum. In
Administrative controls involve human elements including work practices, system maintenance, use of equipment, etc. These controls focus more on reducing the duration of exposure. Administrative controls can be addressed by zoning activities, controlling animal density, job rotation, proper use of maintenance equipment, good housekeeping, personal hygiene, handling of waste clothing, training, and use of personal protective equipment. Facility zoning might involve 3 areas: animal rooms, laboratories, administrative use areas. Maximum occupancy rates should be established per species. Exposure is usually reported as a time rated average. Unfortunately, if time is reduced per person, usually more people need to be exposed. Regular preventative maintenance on ventilation equipment is critical. All animal rooms should be frequently cleaned using wet methods. Particular attentions should be paid to storage and handling of animal wa
Personnel at risk should be provided with suitable PPE including respiratory
protection, laboratory coats, hair bonnets, shoes or shoe covers, gloves,
eye protection. Respiratory protective equipment can help reduce personal
exposure. Two basic types of respirators include 1) supplied air systems,
and 2) air purifying respirators. Supplied air systems provide superior
air protection. In the US, certified air purifying systems must demonstrate
a minimum filter efficiency of 95% for most aerosols (0.3 um). Full face3
aire purifying respiratory fitted with HEPA filters can be most effective
for reducing exposure. Laminar flow powered air-puifying respirators are
marked on the helmet and provide 100% HEPA filtered air. Workers wearing
respirators should participate in a respiratory protection program. Surgical
masks do not provide effective respiratory protection.
Questions:
1. What is the minimum safe exposure level for animal aeroallergens?
2. What is the conventional hierarchy for exposure control of allergens?
What level is most effective?
3. Describe how animal aeroantigens are measured.
4. Animal allergens can be (5X, 10X, 20X) greater during high risk
activities such as bedding dumping.
5. When cleaning animal rooms is the wet/dry method more effective
in reducing aeroallergens?
6. What are the two basic types of respirators?
7. What does PAPR stand for and what does it do?
Answers:
1. There is no clearly established safe level.
2. Hierarchy is: 1) Engineering controls; 2) Administrative Controls
3) PPE. Engineering controls are generally considered most important.
3. Traditional sampling technique uses a calibrated sampling pump with
flow rates of 5 L/min for personal and 60 L/min for area sampling. Filters
are eluted and assayed using the radioallergosorbent test inhibition or
enzyme-linked immunosorbent assay methods.
4. 10 times greater
5. Wet, because animal allergens are water soluble.
6. 1) supplied air and 2) air purifying.
7. PAPR = Laminar flow powered air-puifying respirators and they provide
100% HEPA filtered air.
Laboratory Animal Allergy: a British perspective on a global
problem. ILAR 42 (1): 037.
Since the introduction of health and safety legislation in Britain,
and an increase of knowledge and awareness of the importance of lab animal
allergy (LAA), surprisinlgy there has been little impact on reducting the
incidence of animal occurences in the last 10-20 years. This article examines
why and suggests that prevention of LAA inthe futrure will probably be
directed by the needs of the industry and the adoption of guidelines describing
"best practise" which incoorporates sophisticated engineering methods of
controlling exposure to allergens.
The prevalence rate of LAA varies between 20-30% of animal care workers.
1 of 10 people exposed to lab animals experience asthma, the most serious
symptom of LAA. The incidence rates of work-related eye/nose and skin symptoms
were 7.3/100 person years (# of years a person is afflicted by a certain
condition), and 4.8/100 person years respectively. The minimum incidence
rate of occupational asthma inthe general population is 22 per million
people employed per year. The number of cases of occupational asthma attributable
to lab animals is about 5% of the total cases of occupational asthma reported.
However when the # of cases of occupational asthma attributable to lab
animals is expressed in relation to the # people exposed to animals, the
estimated rate of asthma for this profession is 204 per million people
emplyed per year. This is 10X that of the general working population, but
1/3 of that experienced by spray paint workers. Therefore lab animals have
remained among the most common agents for initiating asthma.
Attitudes toward LAA have changed more quickly in large institutions
and pharmaceutical industries than in academia. There is a trend toward
centralizing animal care services, limiting access to animal units, improving
ventiliation, and ID of individulas for health surveillance.
Currently in legislation there is not a "safe" threshold of exposure
published for animal allergens. Nor is there an "Approved Code of Practise"
for the control of animal allergens. Currently there is the "Health and
Safety at Work Act" which states the employer must provide "so far as is
reasonably practicle" ie balance cost with control measures. The Control
of Substances Hazardous to Health Regulations (The (OSHH) and the Reporting
of Injuries, Diseases and Dangerous Occurences Regulations (RIDDOR) were
introduced in 1988 and 1999. These regulations require from employers 1)
assess the risk to health arising from working with lab animals and their
waste products (risk assessment), 2) decide on what precautions are needed,
3) prevent or control exposure to animal allergens, 4) ensure that control
measures are used and maintained properly, 5) carry out appropriate health
surveillance and keep records for 40 years, and 6) ensure that employees
are properly informed, trained, and surpervised. The most important of
which is the provision of adequate health surveillance. The sooner an individual
with asthma is removed from exposure to the agent, the better the prognosis.
After a report of a dangerous incident to RIDDOR, the health and safety
Executive will instigate an inspection. Most common areas requiring improvements
are risk assessment, health surveillance, and training. They reccommend
the program of surveillance require a questionarie, examination, and lung
function test with a follow-up questionaire at 6 weeks, 6 months, and 1
year after initial exposure. If an individual develops occupational asthma,
then they have the recourse of Social and Civil law. Under Social law,
lab animals are formally recognized as a cause of occupational asthma and
subjects with this disease are entitled to claim compensation from the
government for their disability. Under civil law, those who do successfully
claim statutory compensation are still entitled to sue their employers
for civil compensation inthe courts.
Studies have shown that despite control measure to reduce the exposure
to allergens and protect against symptoms ( use of face masks, air-fed
helmets) the presence of specific immunoglobin IgE1 was still 3-4 X higher.
This suggests control measures protect against symptoms but not sensitization.
Cross sectional studies have shown a relation between the intensity of
exposure and an increased risk of developiong LAA. The prevalence of sensitization
to rats was increased 4.1, 5.0, and 7.2 fold for the low, medium, and high
exposure groups of workers respectivley. Among atopic subjects, the prevalence
rate ratio for sentitization was 7.3 for low exposure, 9.5 for medium,
and 15 for high exposure categories. A 600 fold increase in rat allergen
exposure (when measured by radioallergosorbant test RAST inhibition) was
associated with a six fold increase risk of developing a postive skin prick
test. These results indicated that controlling exposure to animal allergens
is likely to be the most effective way of reducing the incidence of and
preventing of LAA. Analysis of 650 rat-exposed subjects suggest that atopic
workers who are exposed to low levels of rat allegen for only a few hours
per week, are 3 X more likely to be sensitized than non exposed workers.
This risk did not increase significantly with higher intensity or duration
of exposure. In contast, the risk for nonatopic workers increase significantly
only at higher concentrations of rat allergen. This emplies that the lowest
exposures are sufficinet to sensitize atopics, whereas higher levels are
needed for non atopics Therefore the exposure-response curve for atopics
is shifted to the left.
Maximum exposure limits (MELs) are set for most serious health effects
such as cancer and asthma. Occupational exposure standards (OESs) are set
at a level where there is no known risk to health on the basis of daily
exposure and are set for chemicials. Both set concentrations of hazardous
substances inthe air averaged over a specified period of time. There is
no OES for respiratory sensitizers in the UK and no plans to do so. The
reason in part is due to a lack of standardized methods for quantifying
exposure of animal allergens., When RAST was compared to ELIZA there were
large descrepancies inthe results of measuring rat allergen. The use of
monoclonal antibiodies is available for measuring the major rat allergen
Rat n 1 but many other allergens have been found in rat urine. Rat n 1
is the main one in male rat urine but is not secreted much in female rats.
Therefore monoclonal antibodies may not quatify all of the relevant allergens
responsible for exposure. Polyclonal antibody test using rabbit antisera
may offer the best chance of obtaining a standard method of quantifying
exposure to animal allergens.
Still no reliable way of identifying at pre-employment those employees
who will go on to develop LAA. People with "silent" allergy (ie sensitized
but not necessarily experiencing symptoms) can be missed by health surveillance
unless a test for specific IgE is undertaken. Because their is no decline
in the prevalence of LAA, it is time to reconsider what is reasonably practicle.
Following guidelines of best practise, greater reliance placed on engineering
control such as ventilated caging systems and workstations, are recommended.
Questions:
1. What is the main rat allegen called?
2. What is the safe exposure limit set to for animal allergens (OES)?
3. How has the rate of incidence changed over the last several years
from the introduction of legislation to protect workers from occupational
risk?
4. What recommendations are made in this paper to control LAA?
5 In an occupational health and safety program what step is thought
to be the most significant to controling allergies?
Answers:
1. Rat n 1
2. None have been set
3.No decline
4. To follow "best practise" and rely on engineering controls such
as ventilated caging systems and workstations.
5 Employee health surveillance
Medical surveillance of allergy in laboratory animal handlers.
ILAR 42 (1): 047.
Laboratory animal allergy (LAA) is a serious occupational concern.
Common manifestations of LAA are allergic rhinitis, conjunctivitis, asthma,
and urticaria. The prevalence of LAA in animal handlers is about 23%. Incidence
is more difficult to determine, but a range of 2-12% per year of new manifestations
of LAA has been reported. Possible predictors of allergic disease include
a personal history of atopy (family history is less predictive); positive
skin prick testing (accuracy depends on pure allergens); total IgE and
radioallergosorbent testing (RAST) (again, reagent purity affects reliability);
and genetic testing (based on HLA haplotypes). A preplacement history,
physical exam, and ancillary tests (RAST, skin prick) should be used to
identify persons at potential risk for developing LAA, and give a basis
for appropriate counseling on employment choices.
A program of medical surveillance for LAA should include baseline (preplacement)
medical evaluation and testing, with periodic follow-up medical questionnaires,
physical examinations (concentrating on respiratory and skin manifestations),
pulmonary function testing (peak flow and/or cross-shift spirometry), with
other testing (skin test, RAST) as needed for early detection of LAA.
Interventions for the reduction of exposure to animal allergens include
(a) substitution (less allergenic animals, in vitro methods); (b) engineering
controls (ventilated caging systems, modified room ventilation); (c) administrative
controls (required animal handling methods, limited access to animal areas);
and (d) personal protective equipment (PPE). PPE can include respirators,
eye protectors, gloves, coveralls, lab coats, footwear, or other clothing
to reduce exposure. The usefulness of PPE depends on the willingness of
the worker to use it. If respirators are required, there must be a respiratory
protection program, covering quality control, medical approval for use,
and fit testing. If a respirator is necessary, only NIOSH respirators should
be used. However, the use of a respirator has not been shown to reduce
the progression of LAA disease, and severely allergic workers should be
removed from exposure. NIOSH-approved dust masks are often used for nonsymptomatic
workers. These remove 98% of rodent urinary allergens from inhaled air.
Questions:
1. T or F Prevalence is the number of new cases occurring in a population
during a defined time period.
2. T or F A personal history of atopy can predict the subsequent development
of allergy to laboratory animals.
3. What does the acronym RAST mean? What does it measure?
Answers:
1. F Incidence is the number of new cases occurring in a population
during a defined time period. Prevalence measures the number of cases in
a population at a particular time.
2. T A family history of atopy is not a predictive as a personal history
of atopy.
3. RAST = radioallergosorbent test. RAST is an in vitro test that measures
the presence of IgE antibody to a specific allergen.
Introduction: The Science and Pervasiveness of Laboratory Animal
Allergy. ILAR 42 (1): 001.
[Reviewer's Note - Any parts of this introductory article which
recapped specific articles published in this ILAR issue were not reviewed
as other LABSG members will be summarizing these articles for the LABSG
list.] Occupational animal allergy continues to be an important health
problem for lab animal workers as well as an administrative and financial
burden on research institutions due to lost productivity and health care
costs. Up to 46% of lab animal workers develop animal allergies, and more
than 10% of these individuals with symptoms will develop occupation-related
asthma. A rare, life-threatening consequence of laboratory animal allergy
(LAA) is an anaphylactic reaction to animal protein exposure via animal
bites, scratches, and needle sticks. Animal allergies can range from rhinitis
and itchy eyes to respiratory distress. The objective of a responsible
LAA program is to control animal antigen exposure so as to reduce LAA incidence
and to relieve symptoms of sensitive individuals. Exposure control begins
with recognition of antigen sources. Most animals shed allergens through
urine, dander, hair, serum, and saliva. Not all species shed equally and,
in general, females shed fewer allergens. Rats and mice are common shedders
of allergens, but most animals, including invertebrates, can shed and should
be considered as possible allergen sources. Allergen exposure is also related
to allergen particle size, cage environmental conditions, bedding type,
job responsibility, and duration/magnitude of exposure. A hierarchy for
exposure controls consists of administrative controls, engineering controls,
and personal protective equipment (PPE). Administrative controls include
institutional commitment, employee training, and other human elements.
Engineering controls include facility design; heating, ventilation, and
air conditioning specifications, and caging types. While PPE is the most
problematic type of protection and is most burdensome for employees, it
is still important in reducing employee exposure. This issue of ILAR is
intended to complement and update Occupational Health and Safety in
the Care and Use of Research Animals (NRC, 1997) on the subject of
lab animal allergy. While controlling and assessing animal allergen exposure
is key, medical surveillance of animal workers is equally important. The
"Guide" provides some guidance for developing an occupational health
and safety program.
: I have listed questions I wrote for my ACLAM board study group
on the subject of animal allergy based on the 1997 NRC book, Occupational
Health and Safety in the Care and Use of Research Animals. These questions
cover what was discussed in this article as well as this specific ILAR
issue [42(1): Laboratory Animal Allergy].
Questions:
OCCUPATIONAL HEALTH AND SAFETY IN THE CARE AND USE OF RESEARCH ANIMALS
(NRC, 1997)
Chapter 4, pp. 51-64: Allergens
1. What estimated % of lab workers eventually develop occupation-related
asthma?
2. T/F Allergy is most often manifested by cough, wheezing, and shortness
of breath when exposed to lab animals.
3. List risk groups for workers exposed to lab animals based on history
of allergic disease & sensitization to animal proteins.
4. T/F In almost all asthmatic people with lab-animal allergy, nasal
& eye symptoms preceded the development of asthma.
5. Which of the following are examples of anaphylactic reactions?
a. diffuse itching; hives; swelling of face, lips, tongue
b. difficulty breathing due to laryngeal edema
c. asthma with wheezing
d. loss of consciousness due to shock
e. A & B
f. All of the above
6. Allergic reactions are mediated by what class of immunoglobulins?
7. What is the most common route of exposure in lab animal allergy?
8. Mast cells are most abundant in what sites?
9. T/F An autosomal dominant trait with variable statement linked to
genetic markers on chromosome 5 has been linked to people (atopics) more
likely to develop IgE antibodies to allergens.
10. List types of allergic reactions to lab-animal allergens.
11. What are the major sources of rat-allergen exposure?
12. Name a major rat-urine allergen.
13. What is a major mouse allergen?
14. T/F Urine samples from mice contain 100x more Mus m 1 than serum.
15. T/F Female mice excrete 4x more Mus m 1 than males.
16. What are sources of allergens from guinea pigs? What is the major
source?
17. Sources of allergens from rabbits? Which are major and which are
minor?
18. T/F Allergy to cats might predispose workers to the development
of allergy to lab animals.
19. Name the major cat allergen. Where is it produced?
20. Which of the following is false?
a. Fel d 1 is found in all cats.
b. Cross reactivity occurs throughout all species of cats.
c. All cats shed similar amounts of allergen.
d. Male cats might shed more than female cats.
e. Some people can become sensitized to cat albumin.
21. Which of the following does not decrease concentrations of cat
allergen in the air?
a. Use filtered vacuum cleaner
b. Remove carpeting
c. Run high-efficiency air cleaner
d. Wash the cat
e. Increase ventilation rate
22. Name dog allergen. Sources of exposure to dog allergens?
23. T/F Sensitization to primates is common.
24. Name sources of cattle allergens.
25. T/F Horses constitute a highly potent source of allergens.
26. What are sources of horse allergens?
27. T/F There is no evidence of cross sensitivity between deer &
horse allergens.
28. Hypersensitivity pneumonitis due to exposure to birds is due to
what type of antibody?
29. List some ways to detect the presence of specific IgE antibodies
in humans.
30. Airborne-allergen load in an animal room depends on what?
31. T/F Surgical (cloth, paper) disposable masks are effective in minimizing
sensitization to lab animal allergens.
32. Recommended PPE for symptomatic allergic workers? Requirements
to use these PPEs?
33. What does AAAAI stand for?
34. T/F The use of immunotherapy as a means to protect workers from
further symptoms has not been fully established.
Answers:
1. 10%
2. False. Allergy is most often manifested by nasal symptoms, itchy
eyes, and rashes. Symptoms evolve over 1-2 y exposure period.
3. Table 4-1, p. 52.
Normal - no evidence of allergic disease
Atopic - pre-existing allergic disease
Asymptomatic - IgE antibodies to allergenic animal proteins
Symptomatic - Clinical symptoms on exposure to allergenic animal
proteins
4. True
5. f. Anaphylactic reactions vary from mild generalized urticarial
reactions to profound life-threatening reactions.
6. IgE mediated reactions
7. Airborne allergens
8. Resp tract, GI tract, skin (main sites of allergic reactions).
9. True
10. Table 4-2, p.53
Contact urticaria, allergic conjunctivitis, allergic rhinitis, asthma,
anaphylaxis.
11. Urine and saliva
12. Rat n 1A (pre-albumin); Rat n 1B (a2-euglobulin)
13. Mus m 1 (urinary protein); analogous to Rat n 1B (80% homology)
14. True
15. False
16. Dander, fur, saliva, urine. Major source is urine.
17. Major glycoprotein allergen in fur. Minor allergenic components
in saliva and urine.
18. True
19. Protein Fel d 1. Produced in sebaceous glands of skin and in saliva.
20. c.
21. e. Simply increasing ventilation rates from 8 to 40 air changes
per hour in a room containing 2 female cats did not reduce clearance of
airborne cat allergen.
22. Dog allergens - Can f 1, dog albumin. Sources - saliva, hair, skin.
23. False
24. Dander and urine
25. True
26. Dander, skin scrapings, albumin
27. False
28. People with hypersensitivity pneumonitis often have precipitating
IgG antibodies to the protein in question.
29. Skin tests, RAST (radioallergosorbent test), ELISA
30. Rate of production (# of animals), rate of removal (function of
ventilation), relative humidity (increase RH, decrease airborne allergen
conc).
31. False
32. At a minimum, use of a dust-mist respirator certified by NIOSH;
filtered airhood device. Employees using respirators will need resp fit-testing
and medical clearance.
33. American Academy of Allergy, Asthma, and Immunology
34. True