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This Fungus is Everywhere and Wants to Kill Everyone
December 27, 2016 (published)

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You may never have heard of blastomycosis (or if you have, my condolences), but it is caused by a ubiquitous fungus called Blastomyces found in certain parts of the U.S. and it wants to eat your dog and, very rarely, your cat. It lives in soil and sometimes it also wants to eat you (although – important point here – you can’t get it from your dog). You and your dog get it from the same place: dirt. That point is important, so I want to stress it again: Blastomycosis (often abbreviated to just “blasto,” which to me sounds like a really sugary breakfast cereal or the latest aperitif creation from the fine folks who brought us Goldschlager) is not among the diseases we call zoonotic like rabies and ringworm: it doesn’t go from pets to people, or from people to pets.

Since I’m a human and a doctor, but I’m not a human doctor, I can’t talk about the whole wants to eat you part. I can only talk about the wants to eat your dog part, so that’s what I’ll do. (If you have ever had a dog sick with Blasto, I want to point out that I’m not making fun or light of the disease, or any dog that’s ever been sick with it, or died from it.)

Here are the relevant facts about Blasto:

  • It is found in the Midwest, usually around the Great Lakes region.
  • It usually affects the lungs, eyes, and skin of dogs.
  • Symptoms can include anything – weakness, loss of appetite, lethargy, fever.
  • Dogs with the lung form usually cough, stop eating, and lose weight.
  • Dogs with the eye form have red, painful, and swollen eyes.
  • It is very, very, VERY difficult to treat.
  • It’s a part of this nutritious breakfast.

Blasto is one of those diseases that can pretty much do what it wants, where it wants and look like anything. It can look like cancer, it can look like a skin infection…anything. It’s an utterly terrifying disease and when I diagnose it, my heart sinks. I know it’s just trying to survive like the rest of us, but Blasto is mean, nasty, and verging on evil.

The only way to prevent this disease is to move to an area that doesn’t have it.

I hear Antarctica is nice.

Many other parts of the U.S. and the world have their own endemic fungal diseases, like histoplasmosis in the Ohio River valley, and coccidioidomycosis in the Southwest. If you move around, you may just be swapping a risk for one disease for another. (One common thread among fungal diseases is that they are as hard to treat as they are to pronounce.)

In order to diagnose Blasto, you have a few options. Let’s say you have a dog with chronic fevers, and your vet decides to do a chest X-ray as part of the workup. With Blasto it looks like someone took a normal dog chest X-ray and put it in a snow globe: little white globby patches everywhere. A dog with cancer that’s spread to the lungs can look quite similar, which is why blasto is often misdiagnosed as metastatic cancer. For dogs with the lung form (they can have it in many places at once, as well. Did I mention this was a nasty disease?) you can sample the airways with an endoscope in hopes of seeing some of the little fungal organisms, or you can do a pretty convenient and relatively inexpensive urine test that is fairly reliable. The turn-around time is several days, which often frustrates people, but it’s a good way to confirm suspicions of blasto. It’s not 100%, but it’s good: no test is right 100% of the time, a fact pet owners should remember.

For the eye form, many veterinary ophthalmologists are well versed in dealing with it, so if you have a dog with an eye problem that hasn’t resolved after seeing your family veterinarian, ask them about a referral to an eye specialist. Sadly many dogs with the eye form will end up losing the eye due to the damage caused by the fungus.

The skin form is the easiest to diagnose. Dogs with the skin form often have chronic open sores that ooze green goo (which is dead fungus, bacteria and white blood cells: pus), and it doesn’t respond well to antibiotics (more on that below). To diagnose the disease, you can often take some of that green goo, put it on a slide, send it to a pathologist and get your answer in three to five days.

The reason I say doesn’t respond well to antibiotics instead of doesn’t respond at all is that the sores from blasto can become infected with bacteria; remember that blasto is a fungus, a whole different type of organism than bacteria and viruses. If the sores become infected, it’s like a ship full of pirates (blasto) that’s stopped to take on a load of dangerous lunatics (bacteria). You have just added badness to the badness. If you get rid of all the lunatics with antibiotics, you still have a ship full of pirates. That’s what antibiotics do to the skin lesions in blasto, and why they may have a small response to antibiotics.

So what does it respond to? Well, if you’re lucky, it’ll respond to antifungal drugs like itraconazoleketoconazole, or fluconazole. But like much with this disease, it’s not that easy. First, antifungals can cost a lot; depending on the size of the patient, the drug alone can run into the thousands. It doesn’t clear up quickly, either. Dogs who are being treated can take the medication for months on end. And sometimes the medication themselves can have nasty side effects (all medications have the potential for side effects, but antifungals are more likely to make patients feel sick than most drugs we use). However, unlike coccidioidomycosis, the patient doesn’t need to be on an anti-fungal for life after recovery.

One of the most heartbreaking aspects of this disease is that in many cases the treatment can lead to the patient’s death. If the dog has lungs full of fungus, the dead organisms can set off such a strong reaction by the immune system when treatment starts that the inflammation alone can make the lungs worse and kill the patient, or make them so desperate for air that their owners choose to euthanize. It’s like the ship full of pirates setting fire to the ship as it sinks below the water. Treating a dog with the lung form of blasto has about a 50% success rate.

So here’s a summary of my thoughts about blasto:

  • It’s hard to diagnose.
  • It’s impossible to prevent.
  • You have to treat it with a drug that costs thousands.
  • And can make the patients even sicker.

It’s an evil disease. I don’t care if it is just trying to survive. Owners and veterinarians alike often experience an emotion sometimes referred to as helplessness, but unfortunately that's the reality.



March 15, 2018

My dog was just diagnosed yesterday with Blasto after 5 weeks of tests at the local vet, we finally took her to Purdue Vet Research Hospital.  Thankfully they diagnosed it pretty quick.  My dog doesn't have it in her lungs.  She contracted it through an open would in her paw.  She has open sores on two paws, one on the inside of her mouth and one on her gumline....I am horrified that she contracted this nasty, nasty thing.  We live in a wet wooded area, so there is no question this came from our backyard.  She will be on anti-fungal meds for 4-6 months.

March 14, 2018

My sweet Bones has this horrible disease for the 2nd time in her life. She is a "home" dog, who is only outside in our yard to do business, or if we're outside as a family. It's winter in WI, so she could have ONLY contracted this horrible fungus in our own yard. She lost her vision in one eye last summer with her first bout of this, but recovered quite well otherwise. Now she's lost vision in her other eye. She's 8 yrs old, and we're having a hard time deciding if we should continue treating her, or say good-bye and stop her suffering. I don't know if my heart could bear her recovering, and then contracting this nastyness a 3rd time! When we do say good-bye, I'm terrified to get another dog due to the fact that this must be in our yard! My heart goes out to any owner who has been through this!

January 9, 2018

We are going through this now, and treating at home with several drugs prescribed by our vet. We have fungus all over our lawn (near where our dog goes potty), so we suspect this is the culprit. We are not sure what to do to fix the soil, but right now our concern is getting her healthy. She has lameness (which does seem to be improving), absesses that drain, large lymph nodes, swelling in the leg, and bad pneumonia. She is having a difficult time breathing, and has been on the medication for almost a week. Her fever has remained a constant 105 or higher, and this has been so heartbreaking for us. We can't afford to hospitalize her, and we don't want to give up either. We are hoping the medication will kick in soon. We are having to feed her with a syringe with boiled chicken and rice liquefied. We are also having to force her to poop, which has been less than fun to do. She has been more responsive today, and loves when we lay with her and pet her; though she isn't her usual self. This disease is heartbreaking.

April 30, 2017

When our 1 yr old Black Lab was diagnosed, it was devastating! We had never heard of it but immeadiately did our research! Our vet put him on Sporanox right away. He wasn't improving and was put on Fluconazole. It was incredibly expensive! Our vet worked with our local Target Pharmacy and got us a great discount! He had open wounds where his lymph nodes were. We noticed his eyes started to look like he had cataracts. Our vet examined him and gave us the bad news that it had moved to his eyes!! One was worse than the other. The fluconazole was working and the sores started to heal and his lungs were also starting to clear up! We then took him to see a vet optholomigist. He confirmed he was blind in his left eye and the right one was recovering! We were so sad! We met with our vet and decided it was best to have the eye removed and have him neutered. Blasto can be in the testicles. She removed his left eye and neutured him. I just bawled when we picked him up after surgery! He was so excited to see us! Having only one eye has never slowed him down! Our vet did test his eye and testicles and the Blasto was still present in his eye! We made the right choice to remove it! Sammy is going to be 12 in July! He is the best dog EVER!! He had a rough start his first year, but has had a great life and lots of love!! Working with the MN Dept of Health we think he got it from the lake shore at our resort in Northern MN. We never allow him near the lake shore any more! That was hard because he loved the water! He still loves the boat and goes fishing with us. We walk him onto the dock and into the boat! Even with only one eye, his is a great frisbee dog! Without the great care he received from our vet, I don't think he would still be with us!

Kate McDuffee, DVM
April 14, 2017

Hi, Tony! Just FYI. We've got it in the Southeast as well (at least here in North Georgia).

Meg Hoffmann
April 14, 2017

I've known a few dogs lost to Blasto having lived in Northeastern WI where people and dogs alike are killed from it too often. If you decide to treat with the expensive drugs (I know I would try) Walgreens has a Rx drug program that allows dogs (and cats) on it and they give substantial discounts. I've used it for antibiotics because my dogs and I are all Lyme victims so I don't know what the discount would be for the costly antifungals but I would certainly look into it and not give up.

Jan D
April 14, 2017

Is there a way to treat your yard to kill the fungus while it's still in the ground?

Carolyn Hettich
April 14, 2017

Ok...  I'm just moving is to a bubble.

Dawn Reisinger
April 13, 2017

Montana is blissfully lacking in fungal diseases.

Janice La Pinta
April 13, 2017

So if I dig in dirt, for planting, I could get it too?  and does washing hands help ?

April 13, 2017

Sounds like an awful infection.  What about adding Serrapeptase (proteolytic) enzyme to assist the antifungals?

Phyllis Dinsmore
April 13, 2017

Is it related to cryptococcus gatti (sp?)

Victoria Meurer
April 13, 2017

My collie was allergic to several kinds of fungus that are found in dirt. I had to get rid of all my house plants. I read a lot about fungus in the lawn and dirt and it said the best way was to keep the grass cut really short so the dirt has a chance to dry out and also to get rid of as much dead grass as possible because that keeps the ground moist for the fungus to grow. It did help and he was able to lay out in the yard without breaking out in sores.

Sheila Hamlin
April 13, 2017

To scary to comprehend! Never heard of it until this article and I live in Northern Minnesota

April 13, 2017

It is as bad as described...had a dog with it...started with eye, which he lost due to blindness caused by blasto....then came sores over 95% of his body....terrible...then research done on him as test subject, only to die in the end because of complications from everything I stated...check your dogs and cats, ny vets frequently.  It is a very heart breaking disease.

April 13, 2017

One option to try to minimize dogs digging in dirt (where this evil fungus lives) is to set up a sand box for them. If necessary, you can work with a positive reinforcement trainer to encourage your dog to choose the sand over dirt. But, it's an easy and inexpensive option that often works. Good luck, everyone.

January 27, 2017

Oh no, now I have another thing to worry about. Both my dogs are diggers and would dig themselves to China if they could.  I am constantly filling up holes in their yard. How in the world am I going to stop them from doing that now?  I've tried everything I can think of short of coating their whole 1/4 enclosed yard in hot pepper flakes. I'm really at a loss here and will just have to suggest the vet check them for this disease too if they get sick with a mysterious illness. .

Dr. Tony Johnson
January 4, 2017

That's a good point - Sporanox is thought to be better by many internists who treat this condition a lot, but there is paper saying fluconazole is useful as well and it's cheaper.  If starting with itraconazole, use Sporanox at first to be sure it's working.

Taylor Race Sutton
January 1, 2017

Very insightful. A lot of new things learned. It's a damn shame this disease exists.

Patricia R.
December 30, 2016

Ugh!I agree that this is a nasty disease.  I just had a cat diagnosed in upstate NY.   Blastomycosis is everywhere. It was really horrible to treat and the cat didn't make it. One thing that I discovered is that compounded itraconazole is not effective. You need to use sporanox. Thanks for the great info.


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