Published Date: 2009-08-19 14:00:06
Subject: PRO/AH/EDR> Corynebacterium, equine - USA: (CO)
Archive Number: 20090819.2934
CORYNEBACTERIUM, EQUINE - USA: (COLORADO)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Mon 17 Aug 2009
Source: The Denver Channel [edited]
Front Range [Colorado] veterinarians are warning horse owners about a
major recurrence of pigeon fever.
"Pigeon fever is an infection that has nothing to do with birds,"
said Dr Bruce Connally, of the College of Veterinary Medicine and
Biomedical Sciences at Colorado State University (CSU). "It's a
bacterial disease transmitted from horse to horse by flies. It can
[A horse owner says] 3 of the 4 horses she is raising have contracted
pigeon fever. One of them, a Palomino named Cougar, developed several
abscesses on his underside. [The owner] said she grew concerned when
she first noticed the abscesses. "I was even thinking cancer," she
said. "It concerned me." [She] added that she could tell Cougar was
in pain. "He still ate. He still wanted to socialize with the other
horses but his legs stiffened up when he was walking."
Connally said the bacteria, _Corynebacterium pseudotuberculosis_,
which lives in the soil, can enter a horse's body through wounds,
broken skin, or mucous membranes.
Flies transmit the bacteria to other horses when they have been in
contact with the pus from draining abscesses.
When asked how doctors treat the stricken animals, Connally said, "We
usually choose not to use antibiotics. Antibiotics will sometimes
delay the formation of the abscess. Instead, veterinarians generally
apply hot compresses to rupture the abscesses. If they don't rupture,
they are surgically cut to drain the infection."
Connally said that the bacteria in drained pus can survive up to 55
days in the environment. "That's why it's important to control flies,
even though it's difficult to do so."
[The owner of the Palomino] said she is trying. She used to spray her
horses with a fly repellent every week. Now she's spraying them every 2 days.
Connally said that with proper treatment, horses afflicted with
pigeon fever can usually make a full recovery within a few weeks. But
there is a danger. "If these abscesses go inside the internal organs,
this can be fatal," Connally said. "But fortunately that is rare."
The CSU veterinarian said humans won't contract pigeon fever, but can
spread the infectious agent on their shoes, clothes, hands, and barn tools.
[Byline: Lance Hernandez]
HealthMap Alerts via ProMED-mail
[Pigeon fever has many names, but ultimately it affects horses not
birds. Borrowing from this moderator's comment in ProMED-mail posting
Pigeon fever, equine - USA (OR) 20071018.3408 (see reference for full
Pigeon fever, pigeon breast, breastbone fever, dryland distemper,
dryland strangles, false strangles, false distemper are the names
that this disease -- caused by the bacterium _Corynebacterium
pseudotuberculosis_ -- are most frequently known by. Geographically,
it was at one time considered to be a disease of California, where it
is regarded as endemic. However, it is much more widespread now,
especially in the western states of the US, but it has a worldwide
distribution. It is a seasonal disease, usually appearing in late
fall but can appear sporadically at any time of year.
The signs of pigeon fever can also initially resemble those of other
diseases such as strangles. Sometimes the only initial signs are
lameness and a reluctance to move. It can strike a horse of any age,
sex or breed, but usually attacks young adult animals. There is a low
incidence in foals.
It has also been diagnosed in cattle, and a similar disease affects
sheep and goats. The disease is not transmissible to humans, although
humans can carry the infectious agent on shoes, clothing, hands or
barn tools and transfer it to another animal.
Clinical signs include lameness, fever, lethargy and weight loss and
usually is accompanied by very deep abscesses and multiple sores
along the chest, midline and groin area and, sometimes, the back.
Abscesses also can develop internally.
The disease is called pigeon fever because infected animals often
develop abscesses in their pectoral muscles, which swell and resemble
a pigeon's chest. Although the disease is considered seasonal, with
most cases occurring in early fall, a number of cases have been
confirmed during winter months and other times of the year as well.
The causative bacteria live in the soil and can enter the animal's
body through wounds, broken skin or through mucous membranes.
Additionally, some researchers believe pigeon fever may be
transmitted by flies.
Of the types of disease (external abscesses, internal abscesses or
limb infection [ulcerative lymphangitis]), the ulcerative
lymphangitis is the most common form worldwide and rarely involves
more than one leg at a time. Usually, multiple small, draining sores
develop above the fetlock.
The most common form of the disease in the United States is external
abscessation, which often forms deep in the muscles and can be very
large. Usually, it appears in the pectoral region, the ventral
abdomen and the groin area. After spontaneous rupture, or lancing,
the wound will exude liquid, light tan-colored, malodorous pus.
Internal abscesses can occur and are very difficult to treat. The
most common forms are external abscess and lymphangitis, with the
prognosis of a full recovery being generally good. Internal abscesses
are much more difficult to treat. - Mod.TG]
[The state of Colorado in the Rocky Mountain region of the US can be
located on the HealthMap/ProMED-mail interactive map at
<http://healthmap.org/r/00HG>. - Sr.Tech.Ed.MJ]