Aug 21 2016

Protothecosis: The Algae That Kills Dogs!

Prototheca spp is the algae responsible for this disease and it is an obligate saprophytes. This means that this organism has to be on dead matter to survive. For example, tree slime, sewage, animal waste are great environments for Prototheca spp. They are ubiquitous, meaning everywhere, in the environment but have a preponderance for warm, humid climates (did you think Florida?).  The species most troublesome for our dogs and cats is P. zopfii. But why bother telling you about Prototheca spp? Well is a far more common of an infection than we think and often overlooked. How does it start?

  • Skin infection due to trauma is inoculated or contaminated
  • Immunosuppression can facilitate the infection

What are some of the signs in dogs?

  • Colitis : blood in the stools, vomiting, dehydration, weight loss
  • 50% of dogs have central nervous system infections: seizures, altered mentation, wobbliness, weakness, blindness, deafness and more.
  • Eye infections: blindness, corneal edema, retinal detachment and hemorrhage and more.
  • Skin lesions: nodules that can later ulcerate, drain, crust over.
  • Bone infections
  • Cardiac infections can lead to sudden death
  • Boxers, Golden Retrievers and Collies may be more affected.

protothecosis cytology protothecosis

How do we diagnose it?

  • It can be very difficult to diagnose.
  • Blood work can mimic any other disease or be unremarkable
  • Urinalysis can sometimes show the organism: five of 17 dogs with this infection show the organism in the urine.
  • Aspirates of lymph nodes that are swollen, fluid from the eye, spinal fluid, rectal scrapings.
  • Culture is the definitive diagnosis for protothecosis – it grows fast.
  • PCR assays help with spinal fluid, urine and biopsy samples
  • Pathology/biopsies of the affected organs can show the algae.

Treatment and prevention

  • Once this disease is all over the body or central nervous system, the disease is not curable.
  • Antifungal drugs can help for short term: ketoconazole, itraconazole, nstatin, and others.
  • If noted in skin lesions/sores, surgical removal is a must and should be aggressive – know that many of these dogs already have disseminated disease (spread all over).
  • If found in the eye, enucleation is the treatment followed with antifungal but the survival is only about nine months.

So what is the message?

  • Keep your dogs away from decaying matters and environments rich in organic matter. I know, it is easier said than done.

The pictures provided are from the internet and reflect what can be expected with protothecosis infection.   For further questions about this devastating disease, contact Critical Vet Care directly or consult your veterinarian.

criticalvetcarevse | CVC Blog

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