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The
horse industry is BIG BUSINESS in Alabama.
Consider that there are over 100,000 horses in the state,
according to the Alabama Horse Council, and horses account for 20 per
cent of the economic impact that agriculture has on the State of
Alabama.
Swamp
fever is what they used to call it.
That’s because Equine Infectious Anemia used to be so prevalent
in the coastal areas of the Southeast.
The disease was first diagnosed in France in 1843.
Several years later in 1888, it was diagnosed in North America
where it was called Equine Relapsing Fever.
The first extensive epidemic is reported to have occurred in
Wyoming in 1901.
The
virus that causes Equine Infectious Anemia (EIA) is a retro virus from
the lentivirus family, the same virus family as the human AIDS virus.
There is no known threat to humans by the EIA virus.
The lentivirus family has the characteristic of possibly having a
very long incubation period—that is the length of time between
exposure and infection until the host begins to show signs of illness.
That means the virus could be present in an equine host for a
long period of time, yet the animal will appear completely healthy.
While disease can develop within a few weeks of being infected,
it most often takes months to years.
The
virus is most often transmitted by horse flies that feed on the blood of
an infected horse, and then feed on one that is not infected.
It can also be spread by brushes, combs, tack, bits, and using
hypodermic needles on more than one horse.
Once
infected, the horse will remain infected for life.
The disease itself is manifest in three forms:
acute, subacute, and chronic which may become fatal.
In
the acute disease, the horses, ponies, mules, or other equids become
very ill. They will have a
high fever, possibly swelling in the legs and lower abdomen, be
lethargic, and simply appear to be very sick.
In
the subacute form of the disease, the animal will not be as ill as the
acute animal, but will be somewhat sick.
The
chronic phase occurs if the horse survives the acute or subacute phase
of the disease. The chronic animal will have recurring episodes of
illness and may recover, only to have a later episode.
These animals often are on a roller-coaster ride that will
eventually lead to their demise. There
is no effective vaccine and no cure.
For
years, the diagnosis of the disease was complicated and had some room
for error. In 1970, Dr.
Leroy Coggins developed a diagnostic test that could detect not the
presence of the virus, but antibodies to it that an infected horse had
produced. The test is what
we call the Coggins Test. While
it may take up to sixty days for an infected horse to become positive,
it is a very good diagnostic test.
In 1973, the USDA made the Coggins Test the official test for EIA.
In
the State of Alabama, our Veterinary Diagnostic Laboratory runs about
20,000 Coggins Tests annually.
Besides those there are private laboratory companies that will
run many more tests on Alabama horses.
If any private laboratory or our lab gets a positive, the horse
and its herd of origin are retested by animal health officials at our
laboratory, then sent to the National Veterinary Services Laboratory in
Ames, Iowa. Dr. Sara Rowe,
who is in charge of EIA testing at our laboratory, is extremely
conscientious about the tests. The
retest on positives is run in ways to make sure it is not a false
positive. During the past
year, there were 9 positive EIA horses.
Once
the horse is officially declared to be positive, it must be branded with
a cold brand or hot brand with “64A” on the left side of the neck.
Then there are three possible dispositions of the horse.
First it may be euthanized or permitted to slaughter on a
restricted movement permit. The second possibility is to house the horse
in an approved screened stall that will be periodically inspected to
make sure flies are not a transmission factor (nearly impossible).
Finally, the horse may be isolated at least 150 yards from any
other horse for the rest of its life (also periodically checked to
assure compliance).
To
protect your own horses and the equine industry in Alabama, we recommend
that you have your horse tested annually for EIA.
If you have questions about the test, please discuss them with
your local veterinarian. If
you have questions about EIA regulations, call us.
My number is 334-240-7253. |
