Equine
infectious anemia is an incurable and infectious, often fatal
disease.
Horses,
ponies, donkeys, asses and other equine family members are vulnerable
to infection by the disease-causing virus.
Also
known as EIA, other common names for the disease include swamp fever,
mountain fever or malarial fever.
An
estimated 30 percent to 50 percent of infected animals die within two
weeks to four weeks after the onset of clinical signs of EIA.
Transmission
EIA
is spread through blood-to blood contact, not close proximity.
The
virus can be transmitted from an infected animal to “clean”
equine by unsterilized or contaminated needles, blood transfusions,
medical instruments or biting fl ies.
Studies
show as few as three horsefl ies can carry enough virus between
animals to cause infection.
EIA
has no known cure or vaccine.
Infected
horses produce antibodies, which cannot rid the body of the disease.
The
virus can hide and “drift” into various forms, making complete
recovery impossibleand hampering efforts to create a vaccine.
The
Coggins’ and CELISA test methods detect EIA virus antibodies in the
bloodstream.
Symptoms
EIA
can strike in three forms, depending on an animal’s resistance,
strength of the virus, and stress factors like weather or physical
exertion.
Acute
responses generally occur 7 days to 30 days after initial exposure.
Horses may develop fever, go off feed, or die suddenly.
Eventually,
the virus destroys red blood cells, causing severe anemia.
Equine
in the acute stage may test negative for 16 days to 42 days after
exposure, until the animal’s immune system has had time to produce
detectable antibodies.
Chronic
infections produce positive tests and classic symptoms: weight loss,
weakness, anemia, and swelling of the lower legs, chest and abdomen.
Symptoms
subside, but may reoccur. Acute episodes can emerge after stress from
hard work, hot weather, pregnancy or other disease.
Identification
of Positives
Owners
have three options for handling positive animals:
- Permanently quarantine the animal strictly to the owner’s premises at least 200 yards from the nearest equine (including those under the same ownership).
- Euthanasia (at the owner’s expense) after notification of the State Veterinarian.
- Slaughter, after securing a special permit from the State Veterinarian. All other equine in the herd must also be tested for EIA.
Control
Many
countries have control programs requiring equids to be tested for
equine infectious anemia.
State
regulations in the U.S. vary, but most states require one or more
tests, particularly before entry of the horse into the state,
participation in organized activities and/or sale of the horse.
Regular
voluntary testing of the equids on a farm, as well as testing of new
animals before introduction, is helpful in maintaining an EIA-free
herd. No vaccine is available.
Infected
equids become lifelong carriers, and must be permanently isolated
from other susceptible animals or euthanized.
In
the U.S., a reactor must be marked with a brand, freezemarking or a
lip tattoo before it is moved between states.
Reactors
can only be transported between states if they are going to their
home farms, a slaughterhouse, or a diagnostic or research facility,
and they must move under quarantine conditions.
Asymptomatic
carriers often give birth to uninfected foals.
The
risk of congenital infection is higher if the mare has clinical signs
before she gives birth. Foals born to infected mares should be
isolated from
References
No comments:
Post a Comment