Sunday, October 18, 2009

Strangles in Dogs / New Canine Flu Closes Down Shelter

A ProMED-mail post

ProMED-mail is program of the
International Society for Infectious Diseases

Date: 14 Oct 2009
Source: [edited]

Rare pneumonia kills 2 Ottawa dogs
A total of 2 dogs at the Ottawa Humane Society shelter have died from a
rare and severe form of canine pneumonia in the last 2 months. Humane
society veterinarians said they have never seen this type of disease
before. The dogs initially suffer from a cough, lethargy and fever, but the
signs rapidly progress, with the animals coughing up blood and dying within
a day.

The 1st humane society dog developed signs in mid-summer [2009], while the
2nd got sick in early September. Since then, staff have treated every dog
with antibiotics, disinfected every pen, and briefly placed a moratorium on
adoptions. The moratorium was lifted a week ago. Dr Shelly Hutchings, a
humane society veterinarian, said the illness is caused by bacteria --
known as _Streptococcus equi_ -- that typically causes mild disease in
horses. In dogs, infection is rare but severe, causing hemorrhagic
pneumonia. The disease does not spread to humans.

Hutchings said little is known about how dogs contract the disease, and
there is no vaccine to prevent it. "It's frightening for sure," Hutchings
said. "We don't really know what the incubation period is. There's a lot we
don't understand about transmission or which dogs it will affect." Experts
believe dogs in shelters may be susceptible because they are stressed by
cramped quarters and constant barking.

Bruce Roney, Ottawa Humane Society executive director, said the infections
highlight the need for the new shelter, which is slated to open in 2011.
"We don't have proper isolation space in this building," he said. "It makes
[diseases] so difficult to control." Roney said no new cases of the disease
have been seen at the shelter, and the pneumonia hasn't shown up in any
adopted dogs.

The humane society has asked area veterinarians to watch out for the
clinical signs.

communicated by:

[The disease is not necessarily new, but there remains some mystery around
how the dogs acquire it, particularly in those having no apparent contact
with horses. The most common theme of some of these outbreaks has been the
association with pneumonia.

As early as 2002 this was called canine infectious respiratory disease
(CIRD). It was reported following pneumonia and was cultured from airways.

An article, "The association of _Streptococcus equi subsp. zooepidemicus_
with canine infectious respiratory disease" published by Science Direct
includes the following statement: "CIRD is a multifactorial infection that
affects many kennelled dogs despite the wide use of vaccination. Current
vaccines aim to protect against viral agents and a single bacterial agent,
_Bordetella bronchiseptica_. We sought to examine the role of streptococcal
species in CIRD. The isolation and identification of streptococci in the
lower respiratory tract of clinically healthy dogs and those with CIRD were
used to correlate the presence of specific streptococcal species with
respiratory disease. In this study we report that the presence of _S. equi
subsp. zooepidemicus_ is associated with increasing severity of disease in
a population of kennelled dogs with endemic CIRD." The article can be found

_Strep equi_ in canines was also reported in: Canine strangles case reveals
a new host susceptible to infection with _Streptococcus equi_. J Clin
Microbiol 2006; 44(7): 2664-5. doi: 10.1128/JCM.00571-06. See

Another article: American College of Veterinary Pathologists. A clonal
outbreak of acute fatal hemorrhagic pneumonia in intensively housed
(shelter) dogs caused by _Streptococcus equi subsp. zooepidemicus_. Vet
Pathol 2008; 45: 51-3. See

_Streptococcus equi subsp. equi_ is the etiological agent of strangles and
is responsible for nearly 30 per cent of all reported equine infections
worldwide (Chanter, 1997). The very closely related organism _Streptococcus
zooepidemicus_ (_S. equi subsp. zooepidemicus_) has also been found to be a
significant cause of equine lower airway disease, foal pneumonia,
endometritis, and abortion (Chanter, 1997). In dogs, _S. zooepidemicus_ is
associated with hemorrhagic streptococcal pneumonia (HSP) (Garnett et al,
1982). The HSP syndrome is a severe infection, in which sudden death can
occur without any prior clinical signs. In general, dogs with higher _S.
equi subsp. zooepidemicus_ scores of infection were more likely to have
severe alveolar damage (Chalker et al, 2003).

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 per cent of equine 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 equine
guttural pouch samples from 12 established carriers (PCR 76 per cent vs.
culture 59 per cent). PCR also allows differentiation of the 2 subspecies,
_equi_ and _zooepidemicus_.

And ithis article -- Zoonotic transmission of Streptococcus equi subsp.
zooepidemicus from a dog to a handler. J Med Microbiol 2009; (DOI:

indicates that _Streptococcus equi subsp. zooepidemicus_ infection may,
under some circumstances, be a zoonotic disease.

While this may be possibly Canada's 1st case of canine strangles, the
disease has been around for several years. - Mod.TG]

[Equine strangles - Canada: (BC) 20090417.1466]

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