Mycetyoma in a horse–curtains.

This research letter provides an update on a previously reported case of a fungal infection, caused by Madurella mycetomatis, in a horse. The infection resulted in significant tissue growth in the affected area, and upon autopsy, revealed an abundance of fungal aggregates.

Background

• The letter discusses a case of eumycetoma, a severe fungal infection, caused by Madurella mycetomatis in a horse. This case had been reported previously and an update was being provided.
• The mare involved in this case was euthanized following a case of acute colic, an abdominal pain generally common in horses. During her lifetime, the mare had given birth three times and had one miscarriage.

Disease Progression

• In the six years from the first diagnosis until the horse’s death, the infected area saw abundant growth of granulation tissue, a type of connective tissue that forms during wound healing. Despite this growth, the lesion remained localized, and the horse seemed to experience no pain from it. However, it did interfere with the horse’s mobility due to the mass of tissue developing over time.

Post-Mortem Examination

• Post-euthanisation, at the owner’s request, only the affected leg was submitted for pathological and histopathological examination. This refers to a detailed lab examination of the horse’s leg tissue to study the disease’s effects.
• On examination, the granulation tissue contained many foci of fungal aggregates, also known as “granules”. These granules indicate the infection’s presence. Interestingly, the horse’s ligaments and bones were uninfected, implying the infection remained localized to the tissue.
• The findings from these microscopic examinations were in line with the symptoms described in the original report, indicating a consistency in the disease’s manifestation.