Related Experiment Videos
Pyogranulomatous meningoencephalitis due to Actinomyces sp. in a dog
S S Couto1, P J Dickinson, S Jang
1Anatomic Pathology Service, Veterinary Medical Teaching Hospital, Davis, CA 95616, USA.
Abstract:
Actinomyces sp. are commensal, filamentous, gram-positive, acid-fast-negative bacteria that can cause pyogranulomatous inflammation in animals and humans. Central nervous system (CNS) disease is a rare presentation of actinomycosis and is usually due to extension from infected wounds or seeding from distant sites. A dog with progressive, poorly localized neurologic signs had primary CNS actinomycosis without history or evidence of previous trauma or other organ involvement. Histologically, there was a severe pyogranulomatous meningoencephalitis with intralesional filamentous bacteria that were also visible on cytology of the cerebral spinal fluid (CSF) postmortem. Actinomyces sp. was cultured postmortem from the CSF, confirming the diagnosis. This case demonstrates that Actinomyces sp. can be a causative agent of primary CNS disease in dogs.
Insights
Actinomyces bacteria, typically harmless, can cause rare central nervous system (CNS) disease in dogs. This case highlights primary CNS actinomycosis as a cause of progressive neurological signs in canines.
Area of Science:
- Veterinary Neurology
- Microbiology
- Pathology
Background:
- Actinomyces species are gram-positive bacteria, usually commensal, capable of causing pyogranulomatous inflammation.
- Central nervous system (CNS) actinomycosis is uncommon, often resulting from secondary spread or trauma.
Observation:
- A dog presented with progressive, generalized neurological deficits.
- No history of trauma or evidence of infection elsewhere in the body was noted.
- Postmortem examination revealed severe pyogranulomatous meningoencephalitis with filamentous bacteria.
Findings:
- Intralesional filamentous bacteria were identified on cerebrospinal fluid (CSF) cytology.
- Actinomyces species were successfully cultured from the CSF postmortem, confirming the diagnosis.
- Histopathology confirmed severe pyogranulomatous meningoencephalitis.
Implications:
- This case establishes Actinomyces species as a potential cause of primary CNS disease in dogs.
- Highlights the importance of considering actinomycosis in canine neurological cases, even without apparent predisposing factors.
- Suggests CSF analysis and culture are crucial for diagnosing CNS actinomycosis in dogs.