"Swamp cancer": The increasing threat of equine pythiosis - DVM
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"Swamp cancer": The increasing threat of equine pythiosis
Know when to suspect this fungal infection so you can prevent its generally fatal consequences


DVM360 MAGAZINE


Improved diagnosis and treatment


Photo 7: This view of Ebony shows a healed pastern/coronet, and she has been reshod to allow her to begin some conditioning and work.
Pan American Veterinary Labs has developed an enzyme-linked immunosorbent assay (ELISA) that is specific for the presence of pythiosis fungal elements and has greatly helped in the recognition of these cases. A simple blood sample is evaluated, and the disease can be confirmed. This testing can also recognize the presence of Lagenidium (three cases in horses have been confirmed so far).

"We have developed a 'vaccine' to pythiosis that can be used in confirmed cases, and this immunotherapeutic product works by helping the horse modulate the change from T2 helper to T1 helper cell response," says Glass. This product has been shown to have an almost 100 percent cure rate for acute cases (< 15 days) but is less effective in chronic cases (> 60 days). The overall rate of cure is 75 percent for all cases, strongly suggesting that early diagnosis and treatment are crucial to success (Photos 3-7).

Additionally, many clinicians attempt to debulk these large cancer-like growths if diagnosis and treatment have been delayed. This surgical tissue removal is generally associated with poorer skin healing and cosmetic appearance after infection than if the horse is allowed to heal itself slowly. This is another reason for early and proper diagnosis leading to correct treatment and perhaps lessening the need for surgical tissue removal.

"If I could emphasize one thing to veterinarians," Glass says, "it is to move pythiosis up on the diagnostic scale. If you see a horse that has a pythiosis-like lesion that does not respond to antibiotics and standard treatment in the first 10 days, you should think about pythiosis right away."

After getting a good look at these lesions, hopefully, no one will be able to forget.

Dr. Marcella is an equine practitioner in Canton, Ga.


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Source: DVM360 MAGAZINE,
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