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9 EQUINE REVIEW
SPRING 2010
In January this year two horses tested
positive for Equine Infectious Anaemia (EIA) in
Wiltshire after being imported from Romania
via Belgium. These were the first cases of
this disease in Great Britain since 1976,
although there was a serious outbreak in
Ireland in 2006, and as it is a notifiable
disease DEFRA took the decision to humanely
destroy these animals. All horses that are
imported are routinely blood tested for this
disease, a procedure that has shown its
importance in this scenario. Other equine
notifiable diseases include African horse
sickness, contagious equine metritis, equine
viral arteritis, equine influenza and Glanders.
If you suspect signs of any of the notifiable
diseases, you must immediately notify your
local Animal Health Office.
EIA is a viral disease caused by a lentivirus
of the retrovirus family that is closely related
to the one causing HIV in humans. However
EIA is not zoonotic so does not affect humans.
It does affect horses, donkeys and mules
and attacks the animal's immune system with
infected horses
displaying a very
variable set of clinical
features. Acute, subacute,
chronic and subclinical syndromes
are recognised with the severity of the clinical
signs dependent largely upon the virulence
of the strain of virus, the dose of virus and
the host response. The signs seen in the
acute syndrome include intermittent fever,
depression, anorexia, nose bleeds, anaemia,
emaciation and in some cases death.
However, the majority of horses recover
from the viraemia and appear normal for
several days or weeks and then experience
recurrent episodes of fever and depression.
The frequency and severity of these clinical
bouts of disease decreases with time and
often the horse will stop demonstrating any
clinical signs after about a year. These
animals are then carriers for life with the
potential to infect other horses through
transmission by the exchange of blood via
biting flies, especially stable flies (tabanids),
blood products and through the placenta
Equine
Infectious
Anaemia
(EIA)
ANDREW ROBINSON
Millcroft Veterinary Group
January 2010
two horses are tested
positive for Equine Infectious
Anaemia (EIA) in Wiltshire...
...SPECIAL REPORT
EQUINE INFECTIOUS ANAEMIA
FEATURE
Andrew Robinson
Millcroft Veterinary Group