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BLASTOMYCOSIS IN THE DOGhttp://www.thepetcenter.com |
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mammals. It is a great
masquerader and can be mistaken for cancer, viral infections, Lyme Disease and other systemic
fungal diseases such as Valley
Fever. Many dogs have been euthanized or had treatment
delayed because of an erroneous diagnosis of cancer being made.
Blastomycosis in the dog causes weight loss, swollen lymph nodes,
draining sores, coughing, poor appetite, fever, blindness, bone
lesions, etc. The reason there are so many areas
affected is due to the widespread dissemination of the organisms
throughout
the dog's body from the original site which is usually the lungs.
In the environment Blasto is present mostly in the Mississippi,
Wisconsin,
and Ohio River systems.
dust and dirt stirred up when the
soil is disturbed. Especially during dry periods in the
environment, where the soil and spores may become more easily airborne,
the potential for infection with Blastomycosis is greater. The
spores are so tiny that the protective mucous lining of the respiratory
tract is unable to attract all of them... and the spores settle deep in
the alveolar sacs at the end of the respiratory tree. Finding
themselves in a warm, moist and dark environment, rich in nutrients,
the spores become infective yeast-like organisms and multiply in huge
numbers. While inside the dog, the body's normal defense
mechanisms
can simply eliminate these spores and no disease results.
However,
if the load (numbers) of spores inhaled is very great or the dog is
immune
suppressed or stressed by other diseases or poor diet, the organisms
may
begin to reproduce rapidly and signs of disease occur. Once the
spores have taken hold, they grow as single celled yeast forms rather
than
the fungal form. This is why the Blasto organism is called a
biphasic
organism... it can grow in the environment as a fungus and within a
mammal
as a yeast. Click here to see a
large
image (it is 95Kb so it may take a minute to load) of the chest
radiograph
above. |
HUMAN CONTAGION:
It has happened quite often that a dog will be diagnosed with Blasto
and shortly thereafter the human resident of the dog's household will
display malaise, fever, persistent cough and weight loss.
Hopefully
the physician will not be fooled by this disease in disguise and will
establish a diagnosis of Blastomycosis and begin treatment. The
natural question arises: Did the human get the disease from the
dog? The answer 99% of the time is NO. Both human
and dog generally acquire the disease from the same environmental
source in the soil. Likewise the dog rarely will "get Blasto"
from a human companion. The exception occurs where there is
transmission of yeast organisms directly from an open, draining lesion
on the dog into an open wound or directly into
the eye of a human. The transmission of infective yeast cells
from
dog to human or human to dog can occur and result in a localized
infected
lesion. Fortunately this form of contagion is quite rare and
usually
responds quickly to treatment. |
Click on an image to see a full size presentation |
What is the best way to insure that a dog does not fall
under the spell of Blastomycosis or other systemic fungal
infections? Dr. McCullough has a suggestion based upon her
experiences with systemic fungal infections. “Providing a
thorough history is very important to obtain a full picture of what led
up to the animal becoming ill,” says Dr. McCullough. “The client
should inform the veterinarian of the patient's travel history within
the past 6 months and what the daily environment is for the pet (i.e.
camping, swimming, hunting, living near new construction or
landscaping). A thorough history is the key first step toward
figuring out the puzzle. It is just as important to keep an
ongoing dialogue with your veterinarian and to create a plan of action
if the initial tests for an expected disease are negative.”| Canine Blastomycosis | What is Canine Blastomycosis |
Disseminated Blastomycosis in the GSD | Blastomycosis |