PYTHIOSIS INSIDIOSUM… Swamp Cancer. Have you heard of it? Here are 2 success stories and a new treatment… Please tell us your experience!

Monday, May 5th, 2014 | Filed under Medical

I live in California were we don’t have too many swamps.  So, I had  never heard of Pythiosis Insidiosum.  (You readers in Texas and Florida probably know all about this…)

While researching leeches, I came across an article on this nasty fungus and was aghast!

This is the nasty little bugger.

This is the nasty little bugger.

Swamp Fever (as they informally call Pythiosis Insidiosum) is horribly invasive and often fatal.

But, according to a few stories I’ve read, it doesn’t have to be fatal if recognized and treated quickly.

So, I wanted to bring this to the attention of Horse & Man readers, in case you ever have the misfortune of seeing this type of infection on a horse (it also is common in dogs).

This is the least offensive photo I could find.  The fungus is truly nasty.

This is the least offensive photo I could find. The fungus is truly nasty.


I cut and pasted a nice article from the PAN AMERICAN VET LABS website.  You can read the article here.

Equine pythiosis is characterized by the development of cutaneous, subcutaneous, lymphatic and intestinal lesions and less frequently by the involvement of bones and lungs (chronic pythiosis). Lesions caused by P. insidiosum can occur on any part of the horse’s body. Lesions of the lower limbs are more common due to more frequent contact with the organism in infested environments (stagnant water, grasses). The lesions often occur singly, but cases with multiple granulomatous lesions have been encountered. There are no reports of animal to animal, or animal to human transmission of this pathogen. If the disease is not treated in the early stages it is fatal in >95% of cases. In most cases treatment with antifungal drugs is not helpful.

horseshoulderLesions on the limbs are characterized by the formation of tumor like masses with fistulas and a serosanguineous discharge. Lesions on the thorax, abdomen, and shoulders, tend to be circular, 5 to 500 mm in diameter. Ulceration and pruritus (itching) is commonly associated with large lesions. The formation of small hard coral-like masses termed “kunkers” is an interesting characteristic of the disease in equines. These stony masses contain the viable hyphae of P. insidiosum surrounded by cell detritus from degranulated eosinophils. Metastasis (spread) from distant lesions, through lymphatic vessels to regional lymph nodes, lungs, or bones have been reported. Like dog pythiosis, intestinal equine pythiosis is more likely to be acquired by direct inoculation of the organism through ingestion, than spread from distant lesions.

horse neck legHistopathologically, in early equine pythiosis, abundant micro abscesses with eosinophils, a few neutrophils, lymphocytes, and macrophages are present. In chronic cases, an eosinophilic granuloma with giant cells is observed. In the center of the micro abscesses, stony masses (kunkers) are often present. With Periodic Acid Schiff (PAS) and Silver stains P. insidiosum appears as sparsely septate hyphae 6 to 10 mm in diameter.

TREATMENT: SURGERY. The most common treatment of equine pythiosis has been the surgical removal of the lesions. This method is very popular and frequently used by veterinary practitioners. A common short-coming of surgical treatment is its high rate of recurrence. This is due to the incomplete removal of the P. insidiosum from the affected tissues. Additionally, surgical recession of lesions of the limbs is very difficult to accomplish without permanent damage to the surrounding tissues.

CHEMOTHERAPY: Two main groups of Antimycotic drugs have been used to treat pythiosis: Iodine and amphotericin B. Both drugs, however, have given contradictory results. For instance, some practitioners reported that iodine can cure the disease after intravenous injections while others reported failures with the same procedures. In theory, amphotericin B should not work on P. insidiosum due the fact that this pathogen does not have ergosterol (target of the drug) in its cytoplasmic membrane. Nevertheless, the drug has been used with some success in equine pythiosis. The use of drugs in treating pythiosis has been limited because of cost, poor success rate, and high toxicity.

IMMUNOTHERAPY: In the early 1980?s an immunotherapeutic therapeutic product for treatment of P. insidiosum infections in equines was developed in Costa Rica. This early immunotherapeutic product cured 100% of the acute cases (infection 60 days). It was found that horses with chronic infections often become immunodepressed due to the loss of large quantities of proteins, electrolytes and water through the open wounds. Thus, the immunotherapeutic product works better in equine with intact immune system (early pythiosis). A new formulation of this therapeutic vaccine has been introduced by Michigan State University and Pan American Veterinary Laboratories. This new formulation cured 50% of the chronic cases that the original immunotherapeutic product failed to cure. The overall (acute plus chronic) rate of cure of this new immunotherapeutic product was 75%.

 WHAT DOES IT LOOK LIKE? – steel yourselves.

Swamp Fever looks like angry, infected proud flesh.

Basically, if you see any kind of infection that isn’t responding to the regular treatments… quickly have your vet perform the inexpensive ELISA test for Pythiosis Insidiosum.  The sooner you either rule it out or find out… the better.

Chronic cases have been cured, although with less success.

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A typical case of the nasty ‘Swamp Cancer’.

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Heels are in the water, for sure.

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Legs are prime for swimming spores.

It usually happens in the foot and leg area - where the horse has met swamp water... but it can happen on the neck, nose and belly as well.

It usually happens in the foot and leg area – where the horse has met swamp water… but it can happen on the neck, nose and belly as well.

A SUCCESS STORY USING Pythium Immunotherapeutic Product (PIP)

Here is a story off where the distressed owner used PIP.  You can read about the drug PIP and this story on the original website, here.

Puzzle Barton

Puzzle Barton, a seven-month-old Appaloosa filly was brought to my farm, Sugarflats, in November 2004 as a medical lay-up. She had been diagnosed with Pythiosis. The common names for this infection are Florida Swamp Leeches, Swamp Cancer or Phycomycosis. The first veterinarian called to look at her thought she had stepped on something and prescribed antibiotics. A week later, Puzzle was worse, the bulb of her heel was swollen and sore. Puzzle belonged to my mom and dad, they had just lost their home during the hurricanes and they were determined to do everything that could be done to save her. Another vet, Dr. Sally Collins, was called in who immediately recognized Pythiosis and arranged for Puzzle to go the University Of Florida Veterinary School. There Dr. Nicolas Ernst, the Infectious Disease Specialist, decided surgery was not a good option due to her young age and very small legs. He was afraid a tendon or ligament could be severed while trying to cut out the organisms. We had no choice to bring Puzzle home with no real hope to save her.

The infecting organism Pythium insidiosum normally lives in plants such as grasses and weeds, but sends out a thousands of swimming “spores” when the host plant is covered with water. Many cases of Pythiosis are seen each year in Florida and the surge of cases seen in 2004 was surely tied to all the hurricane activity we had last year. In untreated cases this disease spreads rapidly and kills over 90% of all infected animals.
I called my uncle, Dr. Max Ray, DVM, knowing he would know what to do. A 30 year + veterinarian, he believes strongly in doing everything possible to preserve life and during his career had treated horses for “leeches”.
We immediately started supportive treatments to maintain her leg and at least make the environment within the leg inhospitable to the Pythiosis organism using treatments Dr. Ray had often used in his equine practice years ago. Most commonly the treatment for Pythiosis is surgery, cutting out as much of the damaged tissue and Pythium as possible. Another treatment is a potassium iodide IV drip which works in some cases but unfortunately most often it doesn’t. The invading Pythium grows rapidly resulting in huge rotting lesions making euthanasia the end result most frequently.

I sprayed the infected area (the whole bulb of her foot and the sole of her hoof) with Physofix, 3 times daily and then on the second day, wrapped and soaked her whole lower leg and hoof in ammonium alum. A week passed and then another, she was still up and moving around. The vet at the University had thought we would be putting her down in a matter of days as the organism destroyed her tendons and bone in the affected leg.

By now, I will admit, caring for her leg was not for the faint of heart or the undetermined.

Upon talking again with Dr. Ernst in Gainesville he mentioned an experimental immuno therapy for Pythiosis. I immediately called Bob Glass, Pan American Veterinary Laboratories in Hutto, Texas to see how to secure that product for use in Puzzle.

Mr. Glass immediately reassured me that I would receive the Pythium Immunotherapeutic Product (PIP) upon submitting to him a sample of Puzzle’s blood and clearing the use of the PIP with the State of Florida’s Agricultural Dept. Trust me, it was easier to pull the blood sample than get the approval. Unfortunately, it was Thanksgiving week when all this transpired and I couldn’t get anyone at the state to respond to me. Finally, the Wednesday before the holiday, I called every administrative assistant in the State Agricultural Dept. and explained, very emotionally, why it was so important for a quick response from the State Vet. It worked, by that afternoon the typed and signed release required by the lab was faxed to Mr. Glass. He shipped Puzzle’s PIP the Friday after Thanksgiving and I received it on November 30th. By now, Puzzle was rapidly approaching the stage where it was uncertain whether the vaccine would help her or not.

PIP had been proven to be 90% effective on horses diagnosed and started on within 30 days of infection, but only 75% effective in for horses started on it in the 45 day to 60-day range, which is about where Puzzle was on December first, the day of her first treatment. We were also giving her ½ cc of immunregulin, every third day, to boost her immune system. Mr. Glass had explained to me, that the horses that didn’t respond well to PIP usually had seriously compromised immune systems from trying to fight off the organism for an extended period of time.

Pythium Immunotherapeutic Product is a purified extract of the Pythium organism developed during 20 years of research. This therapy actually stimulates the animal’s own immune system to fight the infection.

Puzzle was still in good body condition but seriously sore on her left hind. She had been walking on her toe since arriving at the farm. Her lower leg from the hock down was 3 times larger than normal, raw, and I was keeping a heavy cotton bandage on her for support and protection. What a mess! By now I was alternating the alum soaks with Pet Milk soaks to soothe the damaged tissue. The Physofix really had no affect on the Pythiosis organism, so we stopped it. The infection had moved up to her haunch and we saw signs of it starting to break through her skin on her inner thigh.

Anxiously, I waited for the day I could give the 2nd PIP injection, all the while watching for some sign that the PIP was working. In the 14 days after the first PIP treatment there were no new breakouts and it appeared the lesions on her lower leg and around her hoof were shrinking. By now, the organism had almost completely taken over her lower leg, the coronary band appeared to be compromised and it was eating through her hoof wall.

I was cautiously optimistic, and then on December 14, she shed her frog and the whole sole of her hoof. I started to clean the area and pack the hoof with cotton for support when I noticed how clean and pink the tissue inside the hoof wall was. No sign of the organism or the decaying smell I now associated with it. A small victory!

With a few more days until her final shot on December 21st, we had a huge set back. Over the last week, Puzzle’s appetite had waned and now she spiked a fever. The worst possible had happened, the Pythium infection was clearing but a bacteria had infected the damaged tissue in her haunch, her leg swelled overnight to the size of a small elephant’s. Dr. Ray was out of town, so I started hosing Puzzle down to bring down the fever. I gave her banamine to help with the inflammation and waited for his call. Dr. Ray came out and decided we needed to start her on Cipro and Tetracycline to combat the infection in her leg.

A couple of days passed and the swelling in her leg was subsiding, her appetite was back and I was leaving her leg unwrapped. The leg was doing better, the raw and damaged areas were starting to close up and heal over. The 21st of December had arrived and I gave her the 3rd and final vaccination. The next few days passed uneventfully, her leg was still rather large, but not hot and fevered. Dr. Ray said she might go through life with a “Milk Leg”, the term for an overly large leg, caused by the lymph node being damaged and unable to function properly. That seemed like a small price to pay for her being alive.

On Christmas day I left Puzzle in her stall for the morning while I went to my sister’s house for lunch., When I returned I immediately went to the barn to turn Puzzle out for a little grass. I opened her stall and she walked out FLAT- FOOTED!! For the first time in over 60 days, she wasn’t walking on her toe At that moment I knew we had won.

The next few months passed rapidly, she shed most of her hoof and a new one is growing back in from the coronary band. Completely growing back in, not deformed as we first had feared.

She is walking, running and playing like any normal yearling. Her leg is almost back to normal size and we expect that within a year the only visible sign of what she went through will be the scar left were her lymph node burst open and drained. Upon the advice of Dr. Ray and Mr Glass, we decided to give her another series of PIP, since she was so young, perhaps the youngest horse to receive this treatment and survive. Puzzle will also receive the PIP once a year for life as recent research indicates that it may prevent infection for at least 1 year.

This story is about miracles, Puzzle is a miracle; she is one tough baby, a credit to her breed. We all need to remember that horses have miraculous powers of healing as long as we, their humans, don’t give up.

The great news is that Pan American Veterianry Laboratories has received a USDA liscense to manufacture and sell Pythium Immunotherapeutic Product to veterinarians in the USA. Now this treatment is available for any horse or dog that contracts this deadly disease.
About Us

Pan American Veterinary Laboratories is located in Hutto, Texas. Our facility is equipped with state-of-the-art equipment, and a professional staff experienced in ELISA technology.
Contact Us

166 Brushy Creek Trail
Hutto , TX 78634
Phone: 800.856.9655


I know nothing about this product… just that it is advertised as a cure for Swamp Cancer.  There was an impressive success story so I’m passing it onward.

You can read about Fungus Free Plus and the success story here.

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Treatment of Pythium Insidiosum on Horse Belly

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 PLEASE PASS THIS ONWARD!  Especially to those in swamp states!


OUR MAY BUCKET FUND - THIS IS TOTALLY FIXABLE!  She only needs surgery - one that Texas A&M has performed many times before. To learn more, click image!

OUR MAY BUCKET FUND – THIS IS TOTALLY FIXABLE! She only needs surgery – one that Texas A&M has performed many times before. To learn more, click image!

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2 comments have been posted...

  1. Una L Guidry

    I had a mare that had swamp cancer on her front leg. It was horrible, we had surgery done on her but it was too late. We euthanized her. And then my gelding had it on his fetlock and at first, i didn’t think it was anything more than a cut. But the longer I treated it, the worse it got. My mares mess only made it worse. I ended up using iodine topped with the powdered furizone and the results were astounding. He had kunkers all over his body. I treated them the same way. It’s been 8 years and all he has is a scar left.

  2. Randall

    I had a broodmare diagnosed with this on both front ankles. Packed it with Icthamol covered with a few layers of non stick gauze and vet wrap. Changed once a week and scrubbed with povadine. Dry and Re pack with ichtamol once a week. In 30 days went from a 6″ circle down to a dime size. Must keep it wrapped at all times! Even my vet was surprised with the improvement!

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