Working
with animals entails minimal risk to the careful person. However,
certain hazards exist: animal bites, scratches which may harbor
viruses, bacteria and parasites which can infect humans. Chapter
22 "Selected Zoonoses and Other Health Hazards," pp. 614-648,
from the text Laboratory Animal Medicine , J.G. Fox, B.J.
Cohen and F.M. Loew, eds., 1984, is a good general reference.
Animal
Bites
Prevention
- Assess the
demeanor of the animal before handling.
- Use proper handling techniques.
- Avoid handling injured or fractious animals,
if you lack expertise to do so.
Treatment
- Evaluate the extent of the wound and notify
for help and notify a supervisor.
- Complete a Worker's Compensation Report
for any animal related injury. You may obtain these forms from
the Director
of the Animal Care Facility, the Animal Facility Supervisor,
and the Office of Risk Management.
- If the wound is serious with extensive
bleeding, apply pressure and get help immediately.
- If the wound is superficial, clean and
rinse the area with running water as soon as possible. Cover
the wound.
- Go to the Health Center (students only)
or other appropriate health facility (faculty or staff) for immediate
follow-up.
- Current tetanus immunization is necessary
for personnel working with animals.
Specific
Zoonoses
Rat Bite Fever: The disease may be caused by Streptobaccillus
monilifomis or Spirillum minus. The usual source of infection
is the bite of a rodent. RBF may occur in humans one day to
six weeks following the bite. Signs include regional inflammation
and lymphadenopathy, headache, fever, chills, and a macular
rash. If untreated, further complications may ensue.
Lymphocytic Choriomeningitis : LCM occurs as a latent
virus in the mouse and it is easily transmitted from animals
to humans. Mice and hamsters are asymptomatic carriers. Human
infections have resulted from improper handling of infected
tissues, i.e. directly from feces, urine or inhaling aerosolized
dust from animal rooms. LCM often presents as a mild influenza
like syndrome with or without central nervous system involvement.
Leptospirosis: Leptospira are found in a wide variety
of mammals and reptiles. Hamsters, young guinea pigs and gerbils
are especially susceptible. Rodents can shed leptospires throughout
their life without clinical signs. L. ballum is the most common
servar in rats, mice and rabbits. All excrement and secretions
of infected animals should be considered infective. Leptospirosis
in humans may range from unapparent disease to death.
Tuberculosis: The natural reservoir hosts include
M. avian (birds) M. tuberculosis (humans) and various species
in fish M. marincum, M. pisicum, and M. fortuitum. Transmission
occurs via aerosol from infected animals or by exposure to their
dust bedding. Symptoms in man include anorexia, weight loss,
fatigue, fever, chills, and cachexia and other symptoms dependent
upon the organ system(s) involved. Tuberculosis contracted from
fish have been largely integumentary.
Psittacosis: Avian species are the main reservoir
of C. psittaci infection although the organism has a broad host
range including rabbits, mice, guinea pigs, cats, lambs, calves
and frogs. Transmission may occur by aerosolization of dried
fecal materials which contain organisms from enteric shedding.
Control should be maintained by introduction of animals known
to be free of the disease. Animals of unknown background should
undergo clorotetraacycline chemoprophylaxis. Staff should wear
protective clothing such as masks. Psittacosis in humans may
occur acutely or have an insidious onset. Signs include fever,
chills, anorexia, headache and a respiratory component. A toxic
or septic form of the disease also exists.
Salmonella: Salmonella inhabits the intestinal tract
of many animals. As many as 94% of all reptiles harbor Salmonella
sp. Endemic salmonellosis in commercial raised guinea pigs has
also been a source of infection. Environmental contamination,
feeds of animal by-products and the house mouse all serve as
reservoirs of infection. Both humans and animals are carriers
and periodic shedders of salmonella. Clinically, salmonellosis
in humans presents as gastroenteritis with sudden onset, diarrhea,
nausea, abdominal pain and fever.
Dermatomycoses (Ringworm): Trichophyton mentagrophytes
is the organism most frequently isolated with rodent associated
infections. It may be asymptomatic in rodents and only recognized
when laboratory personnel become infected. Transmission occurs
by direct or indirect contact with visibly infected animals,
asymptomatic carriers, bedding or fungi present in the air or
dust. Control is by regular cleaning of cages and rooms. Clinically,
the infection may manifest as skin lesions with erythema, scaling
and occasionally vesicles or as nail thickening discoloration.
Allergies: Many laboratory animals have been shown
to be responsible for allergic skin and respiratory reactions
in numerous laboratory personnel. Methods to reduce exposure
to offending allergens include reduced animal contact time and
increased room ventilation and cleaning schedule. The use of
filter caps on animal cages, exhaust hoods, protective clothing
and masks, have also been implemented.
Prevention
of Zoonotic Diseases
Proper Personal Hygiene
Colony
Maintenance
- Observe animals for health status on a daily basis.
- Report sick or dead animals. 1) Note health problems.
- Take extra caution in cleaning, etc. a) Isolate affected
animals.
- Record history or progression of animal disease.
- Bring only healthy animals with a known history into an existing
colony.
Other
Potential Zoonotic Diseases
- Pox viruses Shigellosis
- Contagious Ecthyma Erysipeloid
- Hemorrhagic Fever Streptococci
- Yellow Fever Tularemia
- Measles Pseudomonas
- Hepatitis Staphylococcus
- Herpes Virus B Toxoplasmosis
- Marburg Virus Disease Amebiasis
- (African Hemorrhagic Fever)
- Rabies Balantidiasis
- Q Fever Giardiasis
- Rocky Mountain Spotted Fever Cryptosporidosis
- Murine Typhus Helminths
- Brucellosis Cestodiasis
- Plague Listerosis
- Cat Scratch Disease Campylobacteriosis
