Equine Leptospirorosis Vaccine Now Available
Leptospirosis.  Veterinarians face it; horse owners dread it.
Though well-handled in many species, this bacteria has remained
mysterious and problematic in the equine world. 
Cattle, dogs and cats have benefited from  leptospirosis vaccines for years.  At last, there may be one for horses.
The Food and Drug Administration recently approved an intramuscular
vaccine developed by a group of veterinarians and researchers in conjunction
with pharmaceutical company Zoetis, the
world’s largest producer of medicine and vaccinations for pets and livestock.
There is optimism that the medication will reduce the equine infection, which
can effect a variety of organs.
Thehorse.com defines Leptospirosis
as a zoonotic (transmitted between animals and man) bacterial disease found
worldwide that can affect any mammalian species, including humans, wildlife,
rodents, livestock, and, yes, horses. The disease is caused by leptospires,
which are motile (capable of moving) bacteria called spirochetes. Leptospires
are subdivided into serovars and serogroups (subgroups). Those of importance to
the horse include pomona, grippotyphosa, hardjo, bratislava,
canicola, and icterohaemorrhagiae. The incubation period for
leptospirosis in horses is one to three weeks.
Craig Carter, DVM, PhD, director of the University of Kentucky’s
Livestock Disease Diagnostic Center and professor of epidemiology, tells us
horses become infected through mucous membranes of the eyes or mouth and
sometimes through broken skin by contact with infected urine, blood, or
tissues. Horses can become infected by eating hay or grain that has been
contaminated by infected urine, or they can contract it by drinking from
standing water that has been similarly affected. Cattle could introduce
infected urine into ponds or other standing water.
Leptospirosis presents differently in different animals.  In dogs, it presents as flu-like symptoms; in
cattle  as reduced milk production and
abortion. In horses however, the
bacteria appear to collect in different parts of the body, with the most common
being the eyes, kidneys, or reproductive organs, sometimes leading to very
different symptoms between patients. Recurring “moon blindness” or uveitis, is
one of the most common indicators of a leptospirosis infection. Uveitis leads
to eye swelling, cloudiness, discharge, and sensitivity towards light.
 Less commonly, kidney inflammation and failure can be blamed on the
Abortion is also a common
symptom of leptospirosis, with most occurring late in pregnancy and rare
instances of foals being born alive with an active infection. In a study that
included 3527 cases of abortion, still birth and perinatal death, fetoplacental
infection caused by bacteria represented 628 cases,  of which 
leptospirosis was identified in 78 (12.5%)
Some veterinarians had been using the cattle leptospirosis vaccine
in horses as a makeshift in the hope of equine developments; others believed
that the bovine formula could prove detrimental to equines.  “My contention has always been that I could
never take the risk of vaccinating the horses under my care with the cattle
vaccine, because the value of the mares would be such that if I predisposed one
of them to laminitis (inflammation
of the sensitive structures in the hoof called the lamellae),
it wouldn’t be justified based on the risk,” stated Dr. Stuart Brown of Hagyard Equine
Medical Institute.
new vaccine is now available to practitioners for use in equine herds.
This blog is brought to you by Diagnostic Imaging
Systems.  Diagnostic Imaging Systems, Inc. (DIS) provides Quality Imaging
products since 1983. The company combines industry knowledge with an
understanding of the veterinary practice. For more information, go to
Diagnostic Imaging Systems, Inc. website at: www.vetxray.com

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