Page 648 - The Veterinary Care of the Horse

our disease-free status and prevent this virus infecting the UK horse population. All possible

precautions should be undertaken to prevent the virus from becoming endemic.
VetBooks.ir horses have some immunity. The situation on this disease may change and current
In other parts of the world, particularly continental Europe, it is more widespread and

information should be checked with your own vet.

Clinical signs

These are variable and many mildly affected animals may not show any obvious signs.
Possible signs of disease may include:

• fever

• lethargy
• depression

• loss of appetite

• conjunctivitis: the conjunctiva may become swollen and the disease is sometimes

referred to as ‘pink eye’
• nasal discharge

• oedema (swelling) of the lower limbs, the ventral abdomen, the scrotum or udder

• stiffness

• weakness
• abortion or the birth of weak foals: up to 50% of in-foal mares will abort their foetuses

• pneumonia in young foals

• EVA can occasionally be fatal.

Transmission

The disease is transmitted via:

• inhalation of the virus released into the atmosphere as an aerosol during coughing or
snorting

• the teasing or mating process: the virus localizes in the accessory sex glands and is shed

in the semen
• artificial insemination with semen from infected stallions

• contact with aborted foetuses or foetal fluids and membranes.

Following the incubation period (which is an average of 7 days), the virus is excreted in all