Severe Brain Inflammation Linked to Common Fungus in a Pet Dog

Jim Crocker
16th August, 2024

Severe Brain Inflammation Linked to Common Fungus in a Pet Dog

Key Findings

  • A study from Nippon Veterinary and Life Science University documented the first case of granulomatous encephalitis caused by Schizophyllum commune in a dog
  • The dog exhibited severe neurological symptoms, and imaging revealed multiple abnormalities, including brain lesions and systemic inflammation
  • DNA sequencing confirmed S. commune as the causative agent, expanding our understanding of this fungus's ability to cause severe systemic infections beyond the respiratory tract
Schizophyllum commune is a basidiomycetous fungus commonly found on decaying wood. While it is generally considered non-pathogenic to humans and animals, recent studies have shown its potential to cause various infections, particularly in the respiratory tract. A recent study conducted by Nippon Veterinary and Life Science University has uncovered a new dimension to this fungal pathogen by documenting the first case of granulomatous encephalitis caused by S. commune in a dog[1]. In this study, a 10-year-old spayed mixed breed dog presented with severe neurological symptoms. Diagnostic imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), revealed multiple abnormalities. These included a cranial mediastinal mass, bone destruction in the second rib and thoracic vertebra, enlarged lymph nodes, pneumonia, and pleural effusion. MRI scans further detected lesions in the brain's white matter. Upon examining the brain tissue, the researchers found indistinct corticomedullary junctions and discolored white matter. Microscopically, they observed multicentric granulomatous inflammation in various organs, including the brain, heart, kidneys, lungs, and esophagus. Central necrosis and hyaline fungal structures were also noted. DNA sequence analysis identified the causative agent as S. commune. This case broadens our understanding of S. commune as a pathogen. Previously, S. commune was primarily associated with respiratory infections such as allergic bronchopulmonary mycosis (ABPM) and pulmonary fungal balls, predominantly reported in Japan and North America[2]. The fungus has also been identified in a variety of clinical manifestations, including sinusitis and other extrapulmonary conditions, but these were relatively rare[3]. This new study provides evidence that S. commune can cause systemic infections extending to the central nervous system, a severe and previously undocumented manifestation in animals. The findings align with earlier reports documenting the pathogenic potential of S. commune in humans. For instance, a Chinese woman developed a cutaneous granuloma on her foot due to S. commune, highlighting the fungus's ability to cause localized infections[4]. Additionally, a review of 218 global cases of basidiomycete fungi infections pointed out that S. commune was the most common etiologic agent, responsible for a broad spectrum of allergic and invasive diseases[3]. This new case in a dog emphasizes the need for increased awareness and diagnostic vigilance for S. commune infections, especially in unexplained granulomatous conditions. The methodology of the study was rigorous. The researchers employed advanced imaging techniques like CT and MRI to identify lesions and abnormalities. Histopathological examination provided insights into the granulomatous inflammation, and DNA sequencing confirmed the fungal species. This comprehensive approach enabled a precise diagnosis, demonstrating the importance of multi-modal diagnostic strategies in identifying rare fungal infections. This study from Nippon Veterinary and Life Science University underscores the expanding pathogenic profile of S. commune. It challenges the previously held notion that S. commune is primarily a respiratory pathogen by documenting its ability to cause severe systemic infections, including granulomatous encephalitis. This finding necessitates a reevaluation of S. commune's pathogenic potential and calls for more extensive epidemiological studies to understand its prevalence and impact better. In conclusion, the identification of S. commune as the causative agent in this dog's granulomatous encephalitis adds a new layer to our understanding of this fungus. It highlights the need for heightened awareness and more comprehensive diagnostic approaches to detect and manage such infections effectively.

MedicineAnimal ScienceMycology

References

Main Study

1) Disseminated granulomatous encephalitis caused by Schizophyllum commune in a dog with severe neurological signs.

Published 14th August, 2024

https://doi.org/10.1016/j.jcpa.2024.07.004

Related Studies

2) Schizophyllum commune as an emerging fungal pathogen: a review and report of two cases.

https://doi.org/10.1111/j.1439-0507.2012.02190.x

3) Recognizing filamentous basidiomycetes as agents of human disease: A review.

https://doi.org/10.1093/mmy/myu047

4) First report on cutaneous infectious granuloma caused by Schizophyllum commune.

https://doi.org/10.1186/s12879-018-3187-5


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