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In the research setting, exposure
to dogs and pigs can pose potential health risks to humans,
such as infection from dog bites and scratches, allergic
responses, and contraction of pathogenic enteric organisms
through accidental fecal/oral contact. There are many organisms
that may not produce symptoms in dogs and pigs that cause
disease in people. The most common of these disease causing
organisms are discussed below.
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RECOMMENDED PREVENTIVE MEASURES
- Only trained personnel should
handle dogs or pigs. Handling and restraint training can
be scheduled through LARC;
- Gloves, water resistant
shoe covers, and long sleeved apparel should be worn at
all times when working with dogs and pigs;
- Wash hands after handling
animals;
- When seeking medical advice
for any illness, inform your physician that you work with
dogs and/or pigs.
To reduce the risk of exposure to allergens from dogs and pigs
transported to laboratories, staff are advised to adhere
to the following practices:
- Minimize wearing protective
clothing such as lab coats outsides of animal areas and
laboratories;
- Remove transport carts from
labs;
- Use disposable supplies
whenever possible;
- Sanitize lab/surgical areas
after animal work.
- Dust masks should be worn
at all times when working with dogs and pigs; whenever
there is a risk of aerosol transmission of a zoonotic
agent, approved respirator masks (e.g., Type N95 by 3M
company) respirators should be worn instead of dust masks.
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RESPONSE TO INJURY
Dogs may inflict serious bite
and scratch wounds. Prompt first-aid is particularly
important due to the penetrating nature of bites inflicted
by dogs.
- Wash any injured site
with soap and water for at least 15 minutes;
- Control bleeding by applying
direct pressure with a sterile gauze or bandage;
- Cover wound with clean bandage
(do not apply ointment or spray);
- Seek advice from emergency
room physician.
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INFECTIOUS DISEASES
Rabies: Rabies
virus (rhabdovirus) can infect almost any mammal; however
it is very rare in the research environment because dogs
are purchased from high quality sources with excellent vaccination
and disease control programs.
- Reservoir/source: The source
of infection to people is an infected animal. Dogs shed
virus in their saliva 1-14 days before developing clinical
signs. Any random-source (animal with an unknown clinical
history) or wild animal exhibiting central nervous system
signs that are progressive should be considered suspect
for rabies.
- Transmission: Contact with
saliva, mucus membranes, or blood, e.g. bite, or saliva
on an open wound;
- Disease in people: Never
reported in a research facility. Contracted from wild
or unvaccinated animals, rabies in unvaccinated people
is almost invariably fatal.
Brucellosis:
The bacterial organism, Brucella canis, is found
in dogs; B. suis, is the species found in swine.
- Reservoir/source of infection
to people: Can infect dog and swine breeding colonies
where it will be manifested by abortions, infertility,
testicular abnormalities and poor semen quality;
- Transmission: The mode of
transmission of B. canis to people is not clear
but is probably oral or transcutaneous contact with organism-infected
blood or other tissues;
- Disease in people: Flu-like
symptoms that may recur are seen in humans.
Pasteurella multocida:
Has been associated with bites and scratches sustained from
infected dogs.
Capnocytophaga canimorsus:
Also has been associated with dog bites. It can cause serious
systemic illness.
Cryptosporidia:
Cryptosporidiosis (a protozoan infection) associated with
many mammals.
- Reservoir/source of infection:
Many mammals, including dogs and pigs;
- Transmission: Fecal/oral;
- Disease in people: Self-limiting
diarrhea except in immune compromised people where it
can be quite severe. No treatment.
Giardia:
- Reservoir/source: Dogs, non-human primates, other mammals;
- Transmission: Fecal/oral;
- Disease in people: Diarrhea +/- other systemic signs. Usually responds to treatment.
Balantidium coli,
a ciliated protozoan, is another enteric pathogen common
in domestic pigs.
Bacteria: There
are several bacterial pathogens, including Salmonella
spp., and Campylobacter spp., that are frequently
associated with diarrhea in dogs and pigs and may also cause
disease in people.
- Reservoir/source to people:
Symptomatic or asymptomatic animals;
- Transmission: Oral/fecal;
- Disease in people: Diarrhea,
dysentery. Most bacterial pathogens are responsive to
symptomatic and /or antimicrobial therapy.
Enteric Helminths:(such as Roundworms, Tapeworms)
Ringworm: This
dermatophyte infection (most commonly Microsporum
spp. and Trichophyton spp.) is commonly known as
ringworm because of the characteristic circular lesion often
associated with it. Dermatophytes are classified as fungi.
- Reservoir/source to people:
Many species of lab animals may be unapparent;
- Transmission: Direct contact
with infected animal;
- Disease in people: Ringworm
is usually self-limiting, often circular with reddened
rough skin. Responsive to prescription topical therapy.
Leptospirosis:
Leptospira spp. are bacteria found in many animals
but are most commonly associated with livestock and dogs.
Transmission from laboratory rodents to people has been
reported.
- Reservoir/source of infection
to people: Rats, mice, voles, hedgehogs, gerbils, squirrels,
rabbits, hamsters, reptiles, dogs, sheep, goats, horses,
standing water.
- Transmission: Leptospires
are shed in the urine of infected animals. Direct contact
with urine or tissues via skin abrasions or contact with
mucous membranes has been reported. Transmission can also
occur through inhalation of infectious droplet aerosols
and by ingestion;
- Disease in people: Flu-like
symptoms, mild to severe. Death has been reported.
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ALLERGIES
Individuals who have been previously
sensitized to dogs outside of the work place may be at greater
risk of developing allergies to dogs. Exposure to dog allergens
is via saliva, hair and skin.
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