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Leukoencephalomalacia: a mycotoxicosis of Equidae caused by Fusarium moniliforme Sheldon
Abstract:
When 2 horses were dosed with cultures of a Fusarium moniliforme isolate that had previously caused only hepatosis, 1 developed brain oedema and hepatosis, and the other only leukoencephalomalacia. A 3rd horse developed both leukoencephalomalacia and hepatosis after being dosed with another isolate obtained from maize which was associated with a natural outbreak of the nervous form of the disease. Since leukoencephalomalacia and hepatosis could be induced by the same culture material, it was concluded that both syndromes were manifestations of the same toxicosis. There was also some evidence that leukoencephalomalacia might be specifically induced by the administration of smaller doses of the culture material to horses over a longer period. The clinical signs of nervous disorder included ataxia, paresis, apathy, hypersensitivity, frenzy, and other locomotory and psychic disturbances. Autopsy showed that the brains were oedematous, and focal areas of liquefactive necrosis were present in the cerebral white matter. In 1 case the malacic areas were not confined to the subcortical white matter but were microscopically visible in the cerebral cortex as well. An histopathological examination of the areas bordering on the malacic areas revealed rarefication of the white matter, perivascular haemorrhages, oedema and cellular infiltration composed mainly of plasma cells and eosinophiles. Many of the macrophages in these areas contained lipfuscin-like granules, but these granules also occurred extracellularly in the neuropil. In the layers of the cortex nearest the malacic areas, satellitosis and neurophagia were commonly seen.
Insights
Fusarium moniliforme toxicosis in horses can cause both brain edema and hepatosis, indicating a single toxicosis. Leukoencephalomalacia may result from prolonged exposure to smaller doses of the fungus.
Area of Science:
- Veterinary Pathology
- Mycotoxicology
Background:
- Fusarium moniliforme is a fungus known to cause diseases in animals.
- Previous studies linked this fungus to hepatosis in horses.
Purpose of the Study:
- To investigate the relationship between Fusarium moniliforme isolates and equine diseases.
- To determine if leukoencephalomalacia and hepatosis are distinct syndromes or manifestations of the same toxicosis.
Main Methods:
- Dosing horses with Fusarium moniliforme isolates.
- Observing clinical signs and performing autopsies.
- Conducting histopathological examinations of affected tissues.
Main Results:
- Horses dosed with Fusarium moniliforme developed either hepatosis, leukoencephalomalacia, or both.
- Clinical signs included ataxia, paresis, and behavioral changes.
- Histopathology revealed brain edema, liquefactive necrosis in cerebral white matter, and inflammation.
Conclusions:
- Leukoencephalomalacia and hepatosis are likely manifestations of the same Fusarium moniliforme toxicosis in horses.
- Leukoencephalomalacia may be induced by prolonged exposure to lower doses of the toxic agent.