Rhinofacial pythiosis with basilar empyema in a lamb

Area of Science:

• Veterinary Pathology
• Mycology
• Infectious Diseases

Background:

• Pythiosis is a devastating infection caused by the oomycete Pythium insidiosum.
• Ovine pythiosis, particularly affecting the nasal and facial regions, is rare and poorly understood.
• Early diagnosis and treatment are crucial to prevent severe complications and mortality.

Purpose of the Study:

• To report a case of rhinofacial pythiosis with secondary basilar empyema in a lamb.
• To characterize the clinical, pathological, and microbiological findings of this condition.
• To emphasize the potential for P. insidiosum infections to predispose to secondary bacterial infections.

Main Methods:

• Necropsy and histopathological examination of a lamb with facial swelling and respiratory distress.
• Microbiological culture and isolation of bacteria from the sella turcica.
• Immunohistochemical staining using anti-Pythium insidiosum antibody and Grocott's methenamine silver stain for fungal identification.

Main Results:

• A 2-month-old lamb presented with severe facial lesions, including nasal swelling, lip ulceration, oronasal fistula, and hard palate ulceration.
• Necropsy revealed a necrotic mass in the nasal region and purulent exudate in the sella turcica, from which Klebsiella sp. was isolated.
• Histopathology confirmed pyogranulomatous rhinitis associated with P. insidiosum and extensive liquefactive necrosis with bacterial infection in the pituitary region.

Conclusions:

• The case was diagnosed as rhinofacial pythiosis with secondary basilar empyema.
• Nasal lesions caused by P. insidiosum can serve as an entry point for opportunistic bacterial infections.
• This case underscores the severe consequences of P. insidiosum in sheep, leading to potentially fatal secondary infections.