Disseminated protothecosis with central nervous system involvement in a dog

Area of Science:

• Veterinary Neurology
• Infectious Diseases
• Microbiology

Background:

• Prototheca species are algae-like organisms that can cause infections in animals.
• Canine protothecosis is a rare but serious condition, often presenting with neurological signs.

Observation:

• A 4-year-old spayed female mixed-breed dog presented with a 2.5-month history of progressive neurologic deterioration.
• Clinical signs led to euthanasia for humane reasons.

Findings:

• Histopathology, culture, and electron microscopy confirmed the presence of Prototheca organisms.
• Fluorescent antibody testing identified two species: Prototheca wickerhamii and Prototheca zopfii.
• Pyogranulomatous lesions and organisms were disseminated throughout the central nervous system (brain, spinal cord), eyes, kidneys, and heart.

Implications:

• This case highlights the potential for Prototheca species to cause severe, disseminated disease in dogs.
• Accurate species identification is crucial for understanding the pathogenesis and epidemiology of canine protothecosis.
• Further research into diagnostic and therapeutic strategies for canine protothecosis is warranted.