Equine Herpes Virus or Equine Rhinopneumonitis virus or
EHV is a highly infectious viral disease.
EHV-1 can cause abortion, respiratory disease and paralysis.
EHV-4 can also cause abortion but usually causes only respiratory
The virus can survive for 14 - 45 days in the environment and is
spread via the respiratory tract or from aborted fetuses, membranes
Infected foals can also pass the infection onto healthy mares in
their group via their respiratory systems.
Once a pregnant mare is infected she may abort from 4 months
onwards but it is usually between the 8th and 11th months.
ABORTION may take place several months after infection or as
little as 2 weeks later.
WEANED foals and yearlings may develop the respiratory form of
EHV-1 during the autumn and winter months. Older horses can
become infected but these are more likely to be carriers and not
show any signs of the disease. The symptoms are mild fever,
coughing and a discharge from the nose. Blood samples and swabs,
taken from the throat of suspect cases, should be sent to a
laboratory for diagnosis.
FOALING your mare at home is recommended as a precaution
against EHV-1. If this is not possible she should be sent to the
stallion stud at least one month before her foaling date where she will
probably be put into a small group of other healthy, pregnant
mares. It is preferable not to travel pregnant mares with mares
that have aborted or with fillies out of training.
Heat and DISINFECTANTS can destroy the virus so stables
and horse transport should be steam cleaned and disinfected with
an approved product regularly. The virus can survive in dirty
conditions for several weeks.
VACCINATION of all horses and ponies on a stud using an approved
vaccine under veterinary supervision will raise the level of
protection against EHV but it may not provide total protection.