Blastomycosis In Dogs And Cats In

Health care questions and answers about puppies and dogs

What Is Blastomycosis In Dogs?
Questions and answers about Blastomycosis

Blastomycosis, sometimes referred to as "Blasto", is an elusive fungal organism that as part of its life cycle has the interesting nature to exist as a single-celled yeast organism.  The organism grows in certain types of soil as a fungus (or lays dormant as a spore waiting for better conditions).  If soil, humidity, and temperatures are just right the spores grow as a fungus and generates tens of thousands of very tiny spores. If inhaled by a person or animal from disturbed soil the spores evolve into replicating yeast organisms in the tissues!  Blastomyces dermatitidis can infect humans, dogs, occasionally cats and some other warm blooded animals

Images of blastomycosis below...

Health care questions and answers about cats and kittens

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     My dog has Blastomycosis.  The veterinarian took some x-rays and looked at something under the microscope and apparently this disease could be very serious. 
     Do dogs recover from Blasto and will he ever be normal again.  He's lost weight, has a poor appetite and coughs when he gets excited; plus the vet found an infection at one of his toes near the nail.

Answer  blastomycosis... dogs... treatment
 Blastomycosis can be very serious especially when these yeast-phase organisms are present in the lungs or other organs.  Whether or not your dog recovers, and many do with proper therapy, depends on many factors such as immune system vigor, diet, body size, and response of the organisms to medication.  If these tiny yeast-phase organisms invade bone tissue or other areas where blood supply is limited such as the cerebrospinal fluid or skin, it may take months of anti-fungal medications to effect a total cure.  Ocular blastomycosis can cause rapid and permanent blindness. 
     Many dogs seem to get worse for 5 to 8 days after treatment starts, probably because their already overtaxed biochemistry now has to get rid of tens of thousands of dead yeast organisms.  Be sure to stay in close contact with your veterinarian throughout the treatment time and be aware that a flareup of the original infection can occur if the organisms weren't entirely eradicated or possibly from a second exposure to the fungal spores.

           Doctor's Notes
Blastomycosis is called a diphasic pathogen because it exists in two forms.  The infective organisms are extremely tiny particles called spores that grow from the fungal phage of the organism.  Growing on decaying, moist, organic material, usually  close to a bog, stream, lake or river, the fungal form generates thousands of tiny spores. 
     If these little  "seeds" called spores enter the body, usually via inhalation, they can germinate into single celled yeast organisms.  The yeast then propagate via budding... they grow a second self from the first self.
     Morphing from a fungus to a yeast, this biphasic organism can get lucky on occasion and infect humans, dogs, cats and other mammals.

Some patients, no matter how intensive the therapy, may not survive systemic infection with blastomycosis.  It can be mistaken for metastatic cancer on x-ray views, mistaken for tick borne disease if arthritic discomfort and fever are present, mistaken for "kennel cough" or pneumonia.  Identification of yeast organisms  is the best assurance of an accurate diagnosis.  An accurate urine test is now available, too.

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laboratory stain slide blasto
This young dog developed disseminated blastomycosis and did not survive; organisms wewre in the skin, lungs, urinary tract, etc.    An open, draining, non-healing skin lesion from which blastomycosis yeast cells were seen under microscopic exam.  Yes... protective gloves should be worn! A fine needle aspirate (FNA) biopsy samples tissue in the needle that is expressed onto a glass slide for microscopic evaluation The stain is applied to the dried sample material thinly smeared
on the glass slide.
microscope blasto
The slide is carefully viewed for evidence of the blasto organisms.  Often, diligent inspection will present even a single organism... BINGO!  You have the diagnosis! Microscopic view of material obtained via fine needle aspirate biopsy of the chest displays numerous yeast organisms. This stained material was obtained by pressing the glass slide onto an open skin sore and stained with new methylene blue. Cats rarely get blastomycosis but when they do it is very difficult to treat... perhaps because the cat is immune compromised and unable to defend against the fungal spores.

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Related Question:
I heard that people can get blastomycosis from their dog.  Is this true?

Blastomycosis caused this panophthalmitis... extensive eye damage in this dog.

Answer:  blastomycosis... contagion... humans
  Under certain conditions, yes.  The person would need to get the live blastomycosis cells from the dog's lesion into a cut or opening in the skin or somehow get infected material into the nasal cavity or eye tissues or otherwise inoculate themselves with infected material from the dog.  It may be possible that a sneeze from an infected dog could transmit infected respiratory material directly into the eyes or an open wound of the person.  Human disease might then occur especially if the person is immune compromised or is on immune suppressing medications.
      Where a dog and a human in the same household each develop blastomycosis the disease was most likely picked up independently from the same source outside.  People love to garden... dogs love to dig in gardens, people spread topsoil... dogs love to sniff around and dig up topsoil; people dig post holes, rake up waterside debris, explore beaver lodges.  Our dogs often accompany us on these activities and work their sniffers at ground level rooting around organic-smelling soils.  So when a person and their dog develop blastomycosis usually one does not contaminate the other but rather, the dog and human pick up infective spores from a common source in the environment.

Human blastomycosis...
     Humans seldom contract blastomycosis from a dog or cat... but under unique conditions it could happen.

Get a diagnosis!
If your dog or cat is sick your veterinarian will need specific data to  establishing a correct diagnosis. 

     Without that data all your veterinarian can do is make a judgment call such as "it could be..." or "it probably is ..." so for you to get a correct diagnosis your veterinarian will need your permission to do certain tests.

     Blasto organisms are not usually found in the water but rather in the organic, moist soil along shorelines.

I just found out my dog has blastomycosis!  My veterinarian says we live in an endemic area for this disease and she looked for the organisms under the microscope and showed me what they look like.
     The veterinarian says since we got the dog examined before the infection has advanced too far we stand a good chance of curing it but there never can be 100% assurance that he will recover.
     What is blasto, anyways?  How come my dog got it? 

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Answer:   blastomycosis what is... treatment... diagnosis
You and your dog are lucky that the doctor is familiar with blastomycosis.  Endemic means above average numbers of the disease occur in your local area.  Blasto is a  microscopic, yeast-like, single celled organism during the infection and a fungal organism in the environment.  Your dog probably got blasto by inhaling very tiny spores from dried soil that contained the fungal stage of the organism.  
     In dogs the disease is considered very dangerous and often will be fatal if a diagnosis and treatment is delayed or if the patient is not treated with specific anti-fungal medication.  Commonly used antibiotics for bacterial infections will not work against the infective yeast phase of blastomycosis. 
stones Diagnosis:  A positive diagnosis is made by seeing the organisms through the microscope in a sample of tissue or fluid. Sending a serum sample to a lab for a blasto titer may be misleading.  And tissue specimens for a culture of the fungus may take weeks to acquire.  There is a highly reliable urine test available, too.
stones  Treatment:  Some very sick dogs require hospitalization, fluid therapy, and intravenous anti-fungal medications.  Critical care in the hospital for over a week may be needed.  Oral medications such as ketoconazole, itraconazole and fluconazole are often used in addition to antibiotics to assist in controlling bacterial opportunists.   
stones  Prevention:
1.)  Avoidance of close contact with disturbed soil near waterways.  
2.)  Awareness of the usual signs especially if you live in a geographic area where blastomycosis cases have been reported.
3.)  Early examination and proactive pursuit of a diagnosis if your dog is sick.
4.)  Try to inhibiting your dog from digging in the ground.

Organic, damp shoreline soil can be a source of blastomycotic organisms.
     Boggy shorelines, beaver dams and lodges, river and lake edges with organic ,decomposing soil are typical areas where blastomycotic fungi will grow.  Spores from these fungal growths can be inhaled and eventually infect nearly any tissue in the body.

     Dogs that have recovered from a blasto infection can become infected again.  However, we are not certain that the second infection is truly due to a new exposure! 
     It is possible that even after treatment has stopped and a recovery is presumed, some blasto organisms can remain in the dog's body.  Over time they can reproduce and cause illness.
     Most dogs that begin a second set of treatment respond very well and often can recover completely.

Related Question:
My dog was just euthanized because of blastomycosis; it got into his lungs and spread into his eyes and skin.  We thought he had cancer at first but finally the diagnosis of blasto was made and he was doing so poorly, and was blind, we elected to end his suffering.  
     Is there any way to prevent blastomycosis or is there a vaccine against it?  I don't want my other dog to ever get it.

Answer:  blastomycosis...  prevention...
There is no vaccine against blastomycosis, partly because being a yeast organism when infective (and a fungus organism in the environment) it is very difficult to create a vaccine against it.   In your dog's case if you know where he likely was exposed, such as a stream side, topsoil for gardening, digging up a beaver lodge or dam... anywhere there may be richly organic, moist soil could harbor pockets of Blastomyces organisms.
     Dogs that like to dig holes hunting for gophers or chipmunks and dogs that dig themselves a dirt bed to lay in may have greater exposure to inhaling blasto spores associated with the soil.  Blastomycosis does not grow "in the water" of a pond, lake or stream but may grow in the shoreline soil and has been found in the dried mud of beaver lodges and dams.  Below are a few points to remember about blasto...
     blastomycosis  Do not allow your dog to dig holes
     blastomycosis  Have an exam done if any cough, skin sore, or weight loss is noted
     blastomycosis  Swimming is OK but try to avoid boggy or muddy shorelines
     blastomycosis  Fever of 104 to 105 are common during a blastomycosis infection

    Often called Blasto, this disease enters the dog through the respiratory tract when microscopic spores from the fungal phase are inhaled. 
     The spores then develop into budding yeast organisms and can be carried throughout the body through the blood and lymphatic circulation. 

Blasto organisms were easily identified from the non-healing skin lesion on a dog.
     If confined only to the lungs the infection is more likely to be cured than if the organisms have spread to other areas of the body.

Related Question:
What is the usual treatment for blastomycosis and is it always successful in curing the disease?

Answer:  blastomycosis... treatment... dogs
 There are several anti-fungal medications that can be very helpful in eliminating the organisms causing blastomycosis.  Ketoconazole, itraconazole and fluconazole oral medications are often used and are continued for at least a month after all signs of disease have subsided.
     Many patients are so sick they need hospitalization and supportive care.  Therapy for blastomycosis may include i.v fluids, forced feeding, wound management for open and draining lesions, and antibiotics to control secondary bacterial infection.  Protective gloves should be used during patient management of open sores because there is potential for human contagion if yeast organisms enter the caretaker's skin through an open sore.

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You may copy only the text of questions and answers for your own non-commercial use. 
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