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Some
Potential Microbiological Hazards for Field Workers
April
30, 1999
Field
workers should be aware that besides the 'macrobiological'
risks associated with working in a field setting
(e.g. bears, dogs and wasps), there are also microbiological
hazards that people should be aware of. Workers
should consider the animals they deal with and
the organisms that may be associated with these
animals in evaluating the risk that certain situations
may present. Most animals likely contain some
disease and some of these can be contracted by
humans. The routes of entry into a person include:
1.
orally (ingestion): many organisms enter this
way. Wear protection; wash your hands before eating,
drinking or smoking.
2. skin breaks (cuts, abrasions, animal bites):
e.g. tetanus, rabies
3. respiratory route via inhalation (also mucosal
membranes): Hanta virus, rabies,
Knowing how the organisms enter
allows you to use protective clothing (gloves,
eye protection, filter masks) and adopt prudent
practices: wash your hands before eating/drinking/smoking;
wear insect repellent and wear clothing to minimize
exposed skin; and not petting skunks or raccoons.
A list of some microbial agents
that include: bacteria, viruses, protozoans and
worms and some characteristics of the infection
appears below. More detailed technical information
may be found in a binder located
in the MSDS filing cabinet near CW468 in the Biological
Sciences Building. Current information on a wide
variety of microbial pathogens can be found at
Health Canada web site: Population
and Public Health Branch (PPHB) of Health
Canada (formerly Laboratory Centre for Disease
Control).
Go To:
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| Name: |
lockjaw,
tetanus (bacterium) |
| Agent: |
Clostridium
tetani |
| Host |
humans,
animals (including farm animals); in feces |
| Mode
Infection: |
spores
enter through wounds (cuts, abrasions) via soil
or animal feces contamination; common in agricultural
areas |
| Incubation
period: |
~
10 days |
| Symptoms: |
endotoxin
causes severe muscle contractions of neck and trunk;
can be fatal |
| Treatment: |
antibiotics |
| Immunization |
usually
mixed along with diptheria immunization; lasts ~10
years |
| Name: |
cryptosporidiosis
(protozoan) |
| Agent: |
Cryptosporidium
parvum |
| Host |
humans,
poultry, fish, reptile, mammals (small/large) in
feces |
| Mode
Infection: |
Ingestion;
fecal-oral route, animal to person, food and waterborne |
| Incubation
period: |
~7
days |
| Symptoms: |
diarrhea,
abdominal cramps, vomiting |
| Treatment: |
none |
| Immunization |
No |
| Name: |
tularemia,
rabbit fever, deerfly fever (bacterium) |
| Agent: |
Francisella
tularensis |
| Host |
wild
rabbit, muskrat, beaver, some domestic animals |
| Mode
Infection: |
ingestion;
handling infected animals, arthropod bites, inhalation |
| Incubation
period: |
~3
days |
| Symptoms: |
lymph
node swelling or pneumonic disease if inhaled; death |
| Treatment: |
antibiotics |
| Immunization |
available
for occupational risk group |
| Name: |
Beaver
fever, Giardia (protozoan) |
| Agent: |
Giardia
lamblia |
| Host |
humans
and animals (wild and domestic) |
| Mode
Infection: |
ingestion:
fecal - oral on hands or via contaminated water |
| Incubation
period: |
~
8 days |
| Symptoms: |
none
to sudden diarrhea, cramps, fatigue |
| Treatment: |
drugs
available |
| Immunization |
no |
| Name: |
Listeriosis,
listerella (bacterium) |
| Agent: |
Listeria
monocytogeneis |
| Host |
humans,
domestic and wild mammals, fowl; via feces or during
pregnancy/birth |
| Mode
Infection: |
ingestion
(vegetables, dairy), contact with feces or contaminated
soil; handling fetuses possibly inhalation |
| Incubation
period: |
~
7 days |
| Symptoms: |
maybe
pimple lesions on arms |
| Treatment: |
antibiotics |
| Immunization |
no |
| Name: |
rabies,
hydrophobia |
| Agent: |
Rabies
virus |
| Host |
in
animals: dog, cat, fox, wolf, raccoon, sometimes
bats |
| Mode
Infection: |
virus
in saliva transmitted via bite, inhalation or mucosal
route |
| Incubation
period: |
~
4 weeks |
| Symptoms: |
apprehension,
headache, fever; spasms, paralysis, delirium, death |
| Treatment: |
wash
wounds immediately (soap, 70% alcohol) |
| Immunization |
available
for occupational risk group; series takes at least
1 month |
| Name: |
Toxoplasmosis
(protozoan) |
| Agent: |
Toxoplasma
gondii |
| Host |
cats,
other domestic/wild animals, humans |
| Mode
Infection: |
ingestion
of undercooked meat, contam. milk/food/water; soil
contam with feces, inhalation of cysts. |
| Incubation
period: |
~
15 days |
| Symptoms: |
often
none; fever, sore throat, rash; similar to mononucleosis |
| Treatment: |
drugs |
| Immunization |
no |
| Name: |
Trichnellosis,
Trichinosis |
| Agent: |
Trichinella
sp. |
| Host |
humans,
domestic/wild animals, marine mammals |
| Mode
Infection: |
ingestion
of larvae in undercooked meat (esp pork) |
| Incubation
period: |
~
10 days |
| Symptoms: |
muscle
soreness/pain; swelling of upper eyelid, gastrointestinal
symptoms; cardiac/neurologic complications; death |
| Treatment: |
drugs |
| Immunization |
no |
| Name: |
tapeworms |
| Agent: |
Echinococcus
multilocularis , E. granulosus. |
| Host |
foxes,
wolves, coyotes, dogs, cats and herbivores like
voles, lemmings, shrews, mice, sheep, moose |
| Mode
Infection: |
ingestion
of eggs from fecal contamination of water, food. |
| Incubation
period: |
months
to years |
| Symptoms: |
cysts
grow over years, symptom depends on where it is
growing; blindness, seizures, bone breakage |
| Treatment: |
drugs
available |
| Immunization |
see
additional text: "Tapeworms
and Roundworms" |
| Name: |
round
worms |
| Agent: |
Toxocara
sp. |
| Host |
humans,
cat, dog in feces |
| Mode
Infection: |
ingestion;
eggs from contaminated soil or unwashed vegetables |
| Incubation
period: |
weeks
to months |
| Symptoms: |
fever
or altered vision depending on where the larvae
migrate |
| Treatment: |
drugs
available |
| Other |
see
additional text: "Tapeworms and Roundworms" |
| Name: |
West
Nile Virus |
| Agent: |
West Nile
Virus |
| Host |
mosquito,
bird, domestic animals |
| Mode
Infection: |
mosquito
bite |
| Incubation
period: |
3 - 12
days |
| Symptoms: |
fever,
headache, stiff muscles (all range from mild to
severe), most people recover but can be fatal |
| Treatment: |
treat
symptoms and complications of encepahalitis |
| Other |
further information is available
from Health Canada:
Biosafety
Advisory - West Nile Virus
West
Nile Virus Surveillance Information
|
Tapeworm
and Roundworm parasites from contact with Carnivores:
top
of page
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April
30, 1999 |
| |
information
kindly provided by Dr. Allen Shostak |
| Anyone
doing fieldwork with animals should be aware of
some parasitic worms that may infect them. It is
important to remember that their are many parasites
of wildlife that do not normally infect humans but
that are perfectly capable of doing so given the
opportunity. Most of the infections occur via the
fecal-oral route (i.e. eggs from animal feces being
transferred into your mouth) so wearing rubber gloves,
washing your hands/finger nails thoroughly after
contact, possibly wearing protective clothing, avoiding
any instances of hand-mouth contact (no smoking,
chewing gum, nail biting). The most common source
is in handling animal scat and because the eggs
are often long-lived, old scat can be just as dangerous
as fresh material. Infective eggs may also be present
on animal fur although in lesser number than in
the scat.
Some possible tapeworm parasites
are:
Echinococcus granulosus, Echinococcus
multilocularis: adults in carnivores like
wolves and coyotes but cysts may occur in Microtines
such as voles. Eggs ingested from carnivore scats
(and possibly pieces of cysts from mice introduced
via a cut) can cause hydatid cysts to form. These
are difficult or impossible to treat and can be
lethal depending on where they develop in your
body.
Some roundworm parasites include:
Toxocara cati, Toxocara
canis: carried by many carnivores. Ingested
eggs release larvae that migrate aberrantly in
the human body.
Trichinella spiralis:
can infect most mammals. Serious infections typically
arise from consuming under-cooked meat, but handling
raw meat might leave enough larvae on your hands
to cause an infection by ingestion.
There are certainly many other
possible tapeworm and roundworm parasites that
field workers handling animals/scats might be
exposed to. Infection would most typically be
from ingestion of eggs or larvae and less typically
via a cut in the skin.
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Prevention
Summary for Microbiological Hazards: Consider the
route of entry
top of page
1.
Oral route: (many of these diseases)
a).
contamination on hands from soil or animal contact:
-
wear protection (gloves); overalls, eye protection,
particle mask.
- no
eating/drinking/smoking/gum chewing/nail biting
until get cleaned up.
- Wash
your hands with soap/water.
b).
eating/drinking contaminated food/water:
- cook
food well, wash vegetables
- don't
drink water from streams unless filtered or chemically
treated
2.
Respiratory Route: (includes mucous membranes):
(Hanta virus, rabies, rabbit fever)
-
avoid dusts that may be contaminated
- wear
filter mask (HEPA)
- disinfect
area if must work there (find out what you need:
chemical/concentration/time).
3.
Skin cut/animal bite: (rabies, rabbit fever, tetanus)
- wear
protective clothing (gloves, boots, coveralls)
- avoid
exposed skin, wear insect repellant
- don't
pet skunks, raccoons, etc.
Consider
getting immunized for things like tetanus or other
diseases if are engaged in activity that puts you
at greater risk.
updated:
Apr30/99, Mar07/01.
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