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Viruses are known to infect a wide range of hosts, including humans
and wild animals. The usual mode of transmission and dissemination is
through the direct contact or aerosol contact with others of their own
species. Wildlife populations, such as waterfowl, experience epizootics
(epidemics in wildlife) caused by viruses. Duck plague, or duck viral
enteritis, may cause large die-offs in a localized area. People also
experience viruses; for example, the upper respiratory viruses where
epidemics are not uncommon. There are only a few viruses that are
common to humans and wildlife; however, since they have no specific cure,
they can be very serious.
INFECTIOUS AGENT
HOST
Any mammal, usually carnivores; in ND, highest incidence is in skunks,
foxes, bats, and raccoons.
TRANSMISSION
Bite wounds, infected saliva in cuts or skin abrasions, aerosol in bat
caves.
SYMPTOMS
Rabies is almost always a fatal disease of mammals, including humans.
The disease progresses from fever and malaise, to paresis and paralysis
of the muscles, to delirium and convulsions and eventual death due to
respiratory muscle paralysis. In animals, ANY abnormal behavior is
cause for concern, especially a lack of fear of humans and normally
nocturnal animals being out during the day. Domestic animals once formed
the largest reservoir for the disease, but, since the 1960's, wildlife
species, especially skunks, bats, fox, and raccoons, have taken over
that distinction. In 1986, 5,551 cases of rabies were reported in the
United States. Of these, 91 percent were from wildlife species. Rabbits
and squirrels are rarely infected. Human deaths average two cases per
year.
TREATMENT (note: once the disease has developed... there is NO
treatment; this is a FATAL disease)
PREVENTION
Since rabies is such a uniformly fatal disease, emphasis should be
placed on disease prevention. People working with wildlife regularly
should consider preexposure immunization. Mass vaccination of any group
can be very cost-effective. The Merieux Institute, Inc., has developed
a human diploid cell origin vaccine that is highly immunogenic and
effective. This vaccine has improved the positive response of the
vaccine and lessened the overall side effects known with the old
vaccines. The vaccine is USDA approved for 1 ml intramuscular injections
in a series of three doses on days 0, 7, and 21-28, then boostered every
two years. It is also approved for 0.1ml injections intradermally in the
upper arm at the same time intervals as the intramuscular
administration. The best protection for you and the animal in your
care is to avoid being bitten!
Helminths are worms. All species of wildlife carry their own complement
of helminth intestinal parasites. Our domestic animals also have specific
kinds of roundworms. There are two forms of disease produced by these
parasites. Cutaneous larval migrans is a penetration of the skin with
the parasite undergoing a localized migration in or just under the
skin, creating an inflammatory reaction that is self-limiting. Visceral
larval migrans occurs when the eggs of a parasite are ingested and
further penetrate the intestinal tract, where they undergo a migration
through the animal's organs. The amount and severity of the disease
depend on the organs affected. Although only Baylisascaris infection
is described below, any roundworm is capable of tissue migration.
Therefore, handling of fecal matter should always be with the
protection of gloves.
INFECTIOUS AGENT
Baylisascaris procyonis (Raccoon Roundworm)
(others also, see above)
TRANSMISSION
Skin penetration, oral ingestion of eggs. The roundworm of raccoons
is reported to infect at least 70 percent of raccoons in some areas.
For the raccoon, it causes few problems. However, it can cause serious
illness to other animals, including humans. The adult worm can produce
six million eggs per day, passing them in the host's feces.
SYMPTOMS
If accidentally ingested by another species, humans included, the
larvae hatch and penetrate through the intestine, migrating to many
parts of the body. If these larvae migrate into the eye, brain, or
spinal cord, there can be serious, irreversible consequences. Blindness,
central nervous system disease, or even death can result. Children have
died due to this migrating parasite. In adults, eye problems are a more
common result. Other species have roundworms that can sometimes penetrate
the skin, causing a localized self-limiting skin irritation (Cutaneous
larval migrans) in man.
PREVENTION
INFECTIOUS AGENT
Giardia lamblia
HOST
Beaver, muskrat, waterfowl.
TRANSMISSION
Fecal contamination of water and hand-to-mouth transfer of cysts
from feces of an infected animal. Both wild mammals and birds can
harbor these organisms. They presumably have acquired the disease
from infected waters. Waterfowl and aquatic species of mammals are
most frequently infected.
SYMPTOMS
A protozoal infection of the small bowel is often asymptomatic
but may be associated with a variety of intestinal symptoms: chronic
diarrhea, abdominal cramps, bloating, weight loss, and frequent loose,
pale stools.
PREVENTION
INFECTIOUS AGENT
Toxoplasma gondii
HOST
Most commonly the house cat; wild animals
TRANSMISSION
Ingestion of the oocyst (egg); eating undercooked infected meat;
transplacental infection in primary infections of pregnant women.
Although wild animals are often cited as infectious agents for
toxoplasmosis, the domestic house cat is the only species that
passes infective eggs in its feces. All other warm-blooded species
may become infected but are not excreters of the infective eggs.
Other nondefinitive hosts only become infective when they are eaten
by another animal.
SYMPTOMS
The disease is seldom severe and usually is self-limiting. Acute
disease may result in high fever, lymph node enlargement, muscle pain,
and even death. A pregnant woman is particularly susceptible and, when
infected for the first time, often passes the parasite on to her baby.
Up to 3,000 babies are born every year in the United States with ocular
lesions produced from Toxoplasma gondii.
PREVENTION
Confining cats will prevent their contact with wild species. Make
certain to practice good personal hygiene and sanitation. To avoid
children interacting with infected cat feces, keep backyard sandboxes
covered.
INFECTIOUS AGENT
Borrelia burgdorferi (a spirochete)
HOST
Deer ticks, often found on deer, mice, squirrels, weasels, bats.
TRANSMISSION
Tick bites (Ixodes)
SYMPTOMS
Little is known about the signs in wild animals and it is felt that
probably there are not many pathogenic effects on these animals. In
humans, early signs include an expanding ring-shaped skin lesion. Signs
include malaise and fatigue, relapsing fever, myalgia, arthralgia
(muscle and joint pain), headache, stiff neck, and lymph node
enlargement. Days or months later, a chronic or recurring arthritis
may develop which may lead to neurologic or cardiac problems. Other
signs include chills, profuse sweating, vertigo, and varying jaundice.
* * RABIES (Hydrophobia) (Bite Wound Disease)
Rhabdovirus
For humans ONLY: (animal treatment is NOT an option)
D. Helminth Diseases (parasitic)
* * CUTANEOUS AND VISCERAL LARVAL MIGRANS
E. Protozoal Diseases
These are one-celled animal parasites that infect both wildlife and
humans.
* * GIARDIASIS
TOXOPLASMOSIS
F. Tick-Borne Diseases
Several species of ticks are responsible for transmitting diseases
from wildlife species to humans. As these ticks develop from juveniles
to adults, they parasitize several different hosts. In ticks, the
infective organism is transmitted both from the female to her offspring
and between stages of the tick's life cycle.
* * LYME DISEASE
-- adapted from the following:
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