Published Date: 2008-02-12 16:00:16
Subject: PRO/AH/EDR> Equine strangles - USA: (OH)
Archive Number: 20080212.0562
EQUINE STRANGLES - USA: (OHIO)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Sat 9 Feb 2008
Source: HarnessLink.com [edited]
Northfield Park, with the help of an area vet and doctors at The Ohio
State University, is struggling to contain an outbreak of strangles
that has 7 confirmed cases.
Dr Dan Wilson, a Northfield track vet, was first contacted last week
about respiratory illness affecting horses in 6 different barns on
the track. When some of the horses didn't respond to preliminary
treatments, Wilson tested them for strangles and received confirming results.
"At all racetracks there is a lot of respiratory disease, and 99.9
percent of the time not strangles," said Wilson. "We scope their
guttural pouches and took samples from those who did not get better,
and the horses came back positive. You always have strangles in the
back of your mind when you have a sick horse, but you hope not."
Clinical signs of strangles include high fever, loss of appetite, and
enlarged lymph nodes under the chin that often break open and drain.
Though the condition is rarely fatal, it is extremely contagious and
is transmitted via nasal secretions. The snorting of one infected
horse in the wrong place can infect several other animals, as can
using the same brushes or equipment on multiple horses. Treatments
include controlling the fever with anti-inflammatory drugs for the
milder cases and treating the sicker animals with penicillin.
In ideal conditions, infected horses would be quarantined away from
all other horses, but Northfield's capacity backstretch made such a
move impossible. Wilson took immediate steps to quarantine the
affected horses in their stalls and instituted biohazard procedures
that included sterile shoe and body coverings, and disinfectant
washes for those who handle the horses.
Wilson also sent out a plea to The Ohio State University in Columbus,
Ohio, which offered, gratis, the immediate services of Dr Phoebe
Smith, a recent California transplant with expertise in treating
large-scale strangles outbreaks. "With a case like this, in a
high-density population, we are most concerned with biosecurity and
containment," said Smith, who had coordinated outbreak response at
large barns and training facilities in the Golden State. "It's
actually not an extreme number of horses affected, so in that sense
it was not as bad as it could be. But they do have many horses
co-mingled and a fair amount of traffic -- horses arriving and
leaving. They very appropriately recognized that the potential is really bad."
Smith spent 4 Feb  at Northfield to ensure they had instituted
appropriate measures for containment, and found the trainers of the
infected horses were making "excellent efforts. Each was taking it
very seriously and working to make sure it did not become a wildfire
situation," Smith said.
Though there are intranasal and intra-muscular strangles vaccinations
available, the equine community continues to debate their value. Some
ugly, injection-site bumps have been reported on vaccinated horses,
and the vaccine is not 100 percent effective. A study performed by
Louisiana State University revealed, however, that few reactions were
observed in horses that received the vaccination and the severity of
symptoms was reduced in those who contracted the disease after
inoculation. Wilson said he is encouraging those on the track or who
might come in contact with exposed horses to get the vaccine, but
cautioned monitoring of horses before vaccinating. "If you vaccinate
an infected horse it can make them much sicker," he warned.
Legally, Northfield cannot contain the horses, according to executive
vice president of racing and simulcasting Dave Bianconi, but track
officials have notified other racing facilities of the situation. The
Blooded Horse Sale announced yesterday [8 Feb 2008] that it was
withdrawing from its 11 Feb  sale all horses coming from
Northfield. The track also paid half the cost of testing -- about USD
2000 -- for those horses thought to be infected to help ease the
financial burden of already strapped Ohio horsemen. "We feel bad and
want to help horsemen who race here all winter," said Bianconi.
Smith said that as long as the outbreak can be contained at
Northfield, the track and its inhabitants should be clean within 6 weeks.
[Byline: Nicole Kraft, communications director, US Trotting Association]
ProMED-mail Rapporteur Brent Barrett
[The infectious disease strangles is a caused by the bacterium
_Streptococcus equi_. In horses, the disease causes swollen lymph
nodes and a nasal discharge that may resemble pus. The lymph nodes
may swell and burst, thus spreading more bacteria. The horse may be
lethargic and anorectic.
The disease is spread through objects such as water troughs, feed
buckets, brushes, reins, and other equipment if contaminated with
infected pus. Recovered horses can spread the disease for up to 8 or
10 months even though they can appear clinically healthy and normal.
There are vaccines available for preventing the disease. Most often,
antibiotics are used when horses have the disease. Horses need rest
and should be isolated from other horses if they have the disease. - Mod.TG
Northfield Park, a harness racing racetrack, is located in
northeastern Ohio, near Cleveland. The state can be located on the
HealthMap/ProMED-mail interactive map at
<http://healthmap.org/promed?v=40,-97.6,4>. - CopyEd.MJ]