Guttural pouch mycosis, sympathy for Aspergillus nidulans.

The research article discusses the guttural pouch mycosis, a severe fungal infection in horses that frequently involves the species Aspergillus nidulans. This infection, though common, is not well understood, bearing implications for both veterinary and human medicine given that this particular fungus can also cause illness in humans.

Guttural Pouch Mycosis in Horses

• The study begins by discussing the nature of guttural pouch mycosis in horses. The guttural pouches in the horse are air-filled structures located on the pharyngeal cavity’s dorsal side. This anatomical structure is crucial because it is in contact with critical nerves and blood vessels supplying the brain.
• The growth of certain fungal species, especially Aspergillus nidulans, is problematic when it infects the mucous membranes in these pouches. Such infections can lead to the erosion of the carotid arteries, causing significant hemorrhaging and often resulting in the horse’s rapid death.
• Two key initial indicators of this severe fungal infection include nasal bleeding and dysphagia or difficulty swallowing due to the involvement of nerves associated with swallowing.
• The most commonly employed treatment for guttural pouch mycosis is surgical intervention, though the efficacy of antifungal therapy remains questionable.

Role of Aspergillus nidulans

• The fungus Aspergillus nidulans is highlighted for its high occurrence rate in such infections despite its rare presence in other types of fungal illnesses. This fungus is identifiable through its colonies that form reddish, lenticular, and smooth-walled ascospores with cleistothecia surrounded by Hülle cells.
• Surprisingly, this research finds that the occurrence of this fungal disease might be more common than initially thought, although the fungal species involved is rarely identified explicitly.

Implications for Human Medicine

• Interestingly, the article draws parallels to human medicine, referring to the Aspergillus nidulans fungus’s role in invasive aspergillosis found in patients with chronic granulomatous disease. This condition is a rare primary immunodeficiency that chiefly impacts phagocyte function. This fungal species accounts for up to 33% of invasive aspergillosis cases in patients suffering from this disease.
• Typically, invasive aspergillosis is seen in patients with severe hematologic malignancies and immunodeficiencies, and is commonly caused by Aspergillus fumigatus. However, Aspergillus nidulans is responsible for only 1% of these cases, underlining its extraordinary role in specific contexts.

The comparison between veterinary and human medicine underscores the need for more research into Aspergillus nidulans and its unusual behavior in causing diseases.