Streptococcus equi, subspecies
B0019 - Ultrasensitive qualitative detection
of Streptococcus equi,
and zooepidemicus by real time polymerase chain reaction.
included in P0013 - equine
respiratory panel and in
P0024 - equine breeding panel.
subsp. equi is the etiologic agent of strangles and is responsible
for nearly 30% of all reported equine infections worldwide
(Chanter, 1997). Strangles is characterized by pharyngeal
constriction in the horse's upper respiratory tract as a
consequence of lymph node swelling and is often accompanied by
abscessation. The very closely related organism
Streptococcus zooepidemicus (S. equi subsp.
zooepidemicus) is a significant cause of equine
lower airway disease, foal pneumonia, endometritis, and abortion
(Chanter, 1997). There is currently no effective vaccine or
treatment for strangles.
In the past,
identification of S. equi
bacteria usually relied on culture of the bacteria, but this
technique is slow and not very sensitive. A recent study
(Newton, 2000) has shown that repeated nasopharyngeal swabbing
and culture of Streptococcus
equi could not detect the development of healthy
carriers in more than 50% of strangles outbreaks.
S. equi was
sometimes not detected by culture of nasopharyngeal swabs from
carriers for up to 2 or 3 months before nasal shedding resumed
sporadically. The study found that PCR was a more sensitive
technique for detecting S.
equi on swabs: many more known positive swabs were
detected using PCR than using culture (56 of 61 swabs positive
by PCR vs. 18 of 61 swabs positive by culture). Similar results
were obtained for guttural pouch samples from 12 established
carriers (PCR 76% vs. culture 59%). PCR also allows
differentiation of the two subspecies,
Help confirm the disease causing agent
Shorten the time required to confirm a clinical
diagnosis of S. equi
Help ensure that horse populations are free of
Early prevention of spread of this bacterium
Minimize personnel exposure to this bacterium
Safety monitoring of biological products that derive
Chanter, N. (1997) Streptococci and enterococci as animal
pathogens. J. Appl. Microbiol. Symp. Suppl. 83:100S-109S.
Newton, J.R., Verheyen, K., Talbot, N.C., Timoney, J.F., Wood,
J.L., Lakhani, K.H. and Chanter, N. (2000) Control of strangles
outbreaks by isolation of guttural pouch carriers identified
using PCR and culture of Streptococcus equi. Equine Vet J.
swab, or lymph node abscess swab, or gutteral pouch swab, or 0.2 ml fresh, frozen or fixed tissue, or 0.2 ml whole blood in EDTA
(purple top) or ACD (yellow top) tube.
types other than those listed here, please call to confirm
specimen acceptability and shipping instructions.
specimen types, if there will be a delay in shipping, or during
very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain
frozen in transit. See shipping
instructions for more information.
2 business days
real time PCR