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Disease
& Depredation
The feral hog has received a lot of credit for various disease and
depredation problems but is sometimes wrongly accused due to the destructive
nature of some of their other activities. Feral hogs, like all animals, are
susceptible to many infectious and parasitic diseases but probably cause more
problems through rooting, wallowing and depredation. However, if caution is not
used when handling hogs or when feral hogs are around domestic livestock,
disease can be a problem. Disease and depredation, which are already problems
in some areas, will only increase as hog populations increase.
Disease & Parasites
There has been little documentation of many of the diseases of feral hogs
and their spread to livestock and humans. However, there are two diseases
associated with feral hogs that are documented fairly well - pseudorabies and
swine brucellosis. Other diseases hogs may carry are tuberculosis, anthrax and
tularemia.
Pseudorabies is a viral disease of the central nervous system that can affect
domestic and feral hogs and fatally affect cattle, horses, goats, sheep, dogs
and cats. Wild animals such as raccoons, skunks, opossums and small rodents can
also be fatally infected. Symptoms of the virus in these animals are anorexia,
excessive salivation, spasms, convulsions and intense itching followed by
paralysis and then death. Pseudorabies is not related to the rabies virus and
does not infect people. This disease is of special concern to domestic hog
owners because it can weaken pigs and cause abortions and stillbirths, thus
decreasing production and profits. Once infected, the hog is a lifetime carrier
and will periodically shed the virus through the mouth and nose. Transmission
of the disease can be through direct contact, contaminated feed and water,
ingestion of infected tissues, or contaminated trailers.
Swine brucellosis can cause infertility in boars and abortions in sows. This
disease can also cause a loss of production and profit in domestic swine
operations. Swine brucellosis is transmitted through reproductive discharges
such as semen and afterbirth and once infected a hog is a carrier for life. The
only effective way to control this disease is to test and remove infected
individuals, a task impossible to do in a wild population. Swine brucellosis is
contagious to humans and symptoms may range from severe flu-like symptoms to
arthritis or meningitis. There is no cure for this disease in animals while
humans can be treated with antibiotics in an attempt to clear the infection.
The main reservoirs of tuberculosis infection are in man and cattle, however
feral hogs have been found infected with (Mycobacterium bovis) the same strain
of tuberculosis found in man and cattle. Although the M. bovis strain has been
detected in feral hogs, they are not very susceptible. The infection is most
often contracted by ingestion of infected materials. Lesions on the lymph nodes
are good indicators of an infected hog. Fortunately, due to extensive control
measures, this disease is not common. Feral hogs may also carry another strain
of tuberculosis, M. avis, contracted by eating dead birds. This strain is not
contagious to humans.
Anthrax is a serious soil-borne disease that is most commonly associated with
neutral or alkaline soils that serve as reservoirs for the organism's spores.
Recognized endemic areas include portions of Texas, Louisiana, California,
Arkansas, Mississippi, Nebraska, South Dakota and small areas in other states.
Even within these areas, anthrax occurs irregularly and primarily when the
minimal daily temperature is above 60 degrees. Although uncommon, the feral hog
may become infected when feeding. Humans can contract this disease from
contaminated animals or soil. The disease in humans is often fatal if not
promptly treated with antibiotics.
Tularemia is not commonly found in feral hogs but they can contract it through
direct contact or ingestion of contaminated animal carcasses. Ticks are a good
vector as well as a reservoir and the most common source of infection for man.
Persons who dress, prepare or eat improperly cooked feral hogs or other wild
game are also at increased risk.
Feral hogs harbor several parasites some of which might pose problems for man or
other animals. Fleas, hog lice and ticks are some common external parasites
that a hog may acquire. It is thought that feral hogs do not occupy an area
long enough or in sufficient numbers to get infected with large numbers of
internal parasites or facilitate transmission to humans. However, internal
parasites can occur in feral hogs and may include roundworms, kidneyworms,
lungworms, stomachworms, whipworms, liver flukes and trichinosis. Trichinosis
infections in humans are established by consumption of undercooked, infected
pork.
Ranchers, farmers and hunters need to be aware of these potential diseases and
take every precaution to avoid infection. Livestock owners should be sure all
of their animals are vaccinated, especially when there is a chance they may
have contact with feral hogs. There are state and federal laws governing the
transport and relocation of feral hogs. Blood tests are required by law before
feral hogs can be relocated. Hunters, trappers, butchers and wildlife managers
should always wear rubber gloves when handling or dressing feral hogs. Try to
avoid contact with reproductive organs and blood, and wash thoroughly after
contact. Hunters and chefs cooking feral hog meat should make sure it is
thoroughly cooked.
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