Page 642 - The Veterinary Care of the Horse

by coughing and blowing, equine flu is highly infectious within a group of horses. As soon as

a horse shows any symptoms, strict hygiene and isolation procedures should be applied.
VetBooks.ir Ideally, infected animals should be kept a distance of at least 100 metres from other horses.
Any horses that have been in contact with the affected animals should be carefully monitored

with their temperature taken twice daily and not attend shows, lessons etc., as they may be
incubating the disease.

Prevention

Regular vaccination and biosecurity are the key to the prevention of outbreaks of equine
influenza (see Vaccination on page 23).

• A vaccination programme should be established for every horse in the yard. Do not

overlook youngstock, donkeys and elderly companions.
• Pregnant mares should be given a booster one month before foaling to give maximum

protection to the foal.
• In the event of an outbreak, horses should not attend shows or any other equine

gathering. Exposure to the virus combined with the stress of travelling will make
infection more likely.

• When the disease occurs locally, it is advisable to give a booster to any horse that has not

been vaccinated in the previous 6 months, provided they are not thought to be incubating
the disease. Maximum immunity is not reached until 2 weeks after the vaccination

• New arrivals to a yard should be isolated for a period of 2 weeks.

Every now and then an outbreak of equine influenza occurs. Vaccinated horses may show
symptoms but these are usually milder than those experienced by unvaccinated horses. The

reason that vaccines do not always provide 100% protection is because the virus can change
slightly with time and different strains develop. The vaccines are regularly updated in order

to provide maximum protection.

EQUINE HERPESVIRUS (EHV)

There are five types of equine herpesvirus.
• Equine herpesvirus-1 (EHV-1) can cause respiratory disease, abortion, weakness and

paralysis.
• Equine herpesvirus-2 (EHV-2) can cause respiratory disease with pharyngeal lymphoid