1.What is
Strangles -
Strangles is caused by the bacterium
Streptococcus equi. The symptoms classically include
high temperature, coughing, nasal discharge and swollen
and abscessed lymph nodes of the head. The disease may
be fatal if the bacterium spreads to other parts of
the body. However, a nasal discharge without glandular
swelling is frequently all that is observed, and the
carrier state without any obvious clinical signs is
also possible.
The
incubation period is usually about one week but may
be longer. The organism is shed from draining abscesses
and the nose, and it survives in the environment and
water troughs.
Direct contact with infected horses is the most important
means of transmitting the disease. Good hygiene is
essential in controlling the disease. Infection can
be controlled through the isolation of infected horses
and shredders until they are free from infection.
Shredding usually ends rapidly after recovery. However,
shredding may be intermittent. Therefore, before any
convalescent horse or any in-contacts of any infected
horse can be considered likely to be free from infection,
a series of negative nasopharyngeal swabs is needed.
2. Disease prevention -
All horses entering a stud should be monitored closely,
particularly in the period soon after arrival. Any
horses that develop a nasal discharge should be segregated
and swabbed for the presence of S.equi.
3. Disease control -
Spread of strangles can be limited by early detection
of shredders amongst newly affected horses and their
in-contacts by taking 3 nasopharyngeal swabs at 5-7
day intervals over a 2 week period and culturing the
swabs for S.equi. Threee negative swabs indicate freedom
from infection in the great majority of cases but
not all. All young horses are most susceptible to
infection and should be monitored closely. All infected
horses and their in-contact should be placed under
veterinary supervision in strict isolation with highest
possible standards of hygiene. Horses should not enter
an affected stud unless they can be kept in strict
isolation from all sources of infection. No infected
or in-contact animal should be released from isolation
or veterinary supervision unless 3 consecutive negative
swabs have been taken over a 2 week period. Recovered
cases may retain potential carrier status in spite
of undergoing 3 negative swab tests and it is recommended
that the guttural pouch, sinus openings and trachea
are examined carefully with particular reference to
carrier status.
4. Disease notification -
All confirmed cases of strangles and S.equi infection
should be notified to the Thoroughbred Breeders' Associatin
or, for Non-Thoroughbreds, the Welfare Department
of the British Horse Society. It is important that
nasopharyngeal swabs ample the back of the pharynx
adequately. Swabs with extra long shafts andAn enlarged
absorbent head can be obtained from:
Animal Health Trust.
Lanwades
Park,
Kentford,
Newmarket,
Suffolk CB8 7UU
Telephone 01638 5523993
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