Clinical studies on tremorgenic mycotoxicoses in sheep

Area of Science:

• Veterinary Neurology
• Mycotoxicology
• Neuroscience

Background:

• Soil-borne fungi can produce mycotoxins that affect animal health.
• Penitrem A is a tremorgenic mycotoxin known to cause neurological effects.
• Ryegrass staggers is a neurological condition in livestock caused by fungal endophytes.

Purpose of the Study:

• To describe the clinical responses of sheep orally dosed with penitrem A.
• To investigate the neurological effects and potential mechanisms of penitrem A toxicity.
• To determine if penitrem A exposure causes histopathological changes in neural tissues.

Main Methods:

• Sheep were orally dosed with dried mycelium containing penitrem A for 7-14 weeks.
• Clinical signs, including tremors and incoordination, were monitored.
• Neurotransmitter amino acid release from corpus striatum nerve endings was assessed in vitro.
• Histopathological examination of neural and other tissues was performed.

Main Results:

• Sheep exhibited initial tremors that progressed to an incoordination syndrome resembling ryegrass staggers.
• Protracted staggers symptomatology correlated with in vitro changes in neurotransmitter amino acid release.
• No significant histopathological lesions were found in neural or other tissues examined.

Conclusions:

• Penitrem A causes a reversible neurotoxicosis in sheep characterized by tremors and incoordination.
• The neurological effects are associated with alterations in neurotransmitter release in the corpus striatum.
• The absence of histopathology suggests a functional rather than structural basis for the observed neurotoxicity.