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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 itraconazole, ketoconazole, 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.
83 Comments
Kayla
March 12, 2024
I would like to start by saying this was a rollercoaster.. I just moved upstate and my 9 year old Canis Panther randomly got ill.. limping and seemed blind and deaf over a few days then when he stopped using the bathroom I made an appointment with the vet. He then peed blood the next day and since I live in the country no vet was open the day of the vet visit I noticed my boys paws were swollen like a balloon I was in extreme distress as my body could not walk or seem to see all in this one day. Needless to say he was put down immediately that morning as I called them in complete disbelief and shock she came out and did a home visit to put reaper down. She thought it was lymphatic cancer of some sort. I remember him waving his head back and fourth for such a long time she basically had to give him the entire syringe of sleepy and heart stopping meds. I was devastated and he was too. His last breathe went deep into my lungs and still to this day I’m petrified.. my step son also passed away from blastomycosis as well.. but I’ve done so much research on blastomycosis I could label the cell structure of the thing. This is a nightmare.
Aleta
December 27, 2023
I've been researching because it's too weird that both my dogs got sick and no one put this together. My therapy dog, my life, my velcro, died suddenly early Monday morning. She was fine Saturday. Playing, eating, snuggling. Then around midnight she stumbled and I tried to help her in the couch and realized she couldn't see. And seemed she couldn't hear. But otherwise seemed good and was getting along. Sunday she was good, ate, chilled, walked around outside and then collapsed. She couldn't open her eyes, foaming at the mouth. I took her to er and she was in a coma, swelling on the brain but no one could answer why, what, where, how, wtf?!? She got Keppra and prednisone iv and perked up. So thought it was a seizure. She wasn't stable so I had to leave her. She went into cardiac arrest and died at 7 am. I am still screaming at every turn. I need her. Well something just felt off especially since Marley has been dragging her front foot, even on her pain meds and then started to cough a couple days ago. I dropped Marley off at the regular vet while I went to pick up Sasha. When I got to pick up Marley the vet just looked at me and I knew. She took me in where Marleys x-rays were. I fell to the floor. I couldn't believe my eyes and neither could the vet. She said she had never seen this so bad. She did mention it was like "a fungal infection" and I immediately asked if it's my environment. She took her time saying no. But this isn't just coincidence. We moved here in July and Sasha never presented any symptoms. I had both at the vet in October for bw because they were losing weight but no one was concerned (south in summer). I had to keep looking into this. I really don't know how I'll make it through this. Sasha suddenly leaving me was devastating. And now Marley. You can't even count the number of little masses. Why didn't the vets catch this? And what can I do about my property?
Lila
August 23, 2023
I have a 1.5 year old great dane who about 5 weeks ago started showing signs of being sick. I took him to the vet and was given antibiotic's and three other medications... 2 weeks later he wasn't getting any better and he had lost a significant amount of weight. Went back to the vet and 3 hrs later I was shown an xray of his lungs and it was full of "spider webs" at least thats what it looked like to me. The night before I took him to the vet I ran into an article about Blastomycosis and I thought there is no way... but come to find out it was very much true. No idea where it came from as he doesn't leave our property. So not only do we have a dog who now has this horrible infection, but we also need to figure out where this came from so he doesn't get it again. This will be day 8 on Itraconazole and believe me the first 5 days was questionable and it didn't seem like he was going to get any better. Day 6 he was getting his old personality back and day 7 seems to be doing good... then today woke up with a runny nose and breathing heavy again, doesn't want to eat anything but Chicken and Rice. I feel like we are on a roller coaster that is just always going up and right back down. The one thing I have been thankful for is the support of our local Walgreens as our vet didn't stock this medication but they did. While the normal price is $286.00 for 30 pills the pharmacist was great and found a discount program that brought it down to $41.56. Its still roughly 80 bucks a month for his medication but that's way better than $600! I cant say how much I appreciate this article because I was unaware that there was a urine test that could be done affordably.. the only test I was told about is through blood and it was about $500. I would spend what I had to but if there is more affordable option that gets the same end result why not.
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January 7, 2022
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