Clinical and pathological aspects of an outbreak of equine leukoencephalomalacia in Spain.

The study investigates an outbreak of leukoencephalomalacia in horses (equids) in Spain during 1988, caused by the ingestion of corn contaminated with a pinkish Fusarium moniliforme fungus and reports the clinicopathological findings.

Research Context

• In 1988, an epidemic of equine leukoencephalomalacia occurred in Spain, and the horses that had consumed corn infested with Fusarium moniliforme- a pinkish fungus- turned out to be the victims.

Clinical Observations

• The research notes that the symptoms of the disease appeared rapidly and were quite severe. The affected horses were observed to have overexcitement, blindness, incoordination, and even facial paralysis.
• Notably, the death of the horses happened within 24 hours of the appearance of symptoms. This suggests that the impact of the fungus-induced disease was acute and fatal.

Pathological Findings

• The pathological alterations caused by the disease were primarily constrained to the central nervous system of the afflicted horses.
• On a macroscopic level, these changes comprised hyperemia (excessive blood in the vessels) and hemorrhages. The consistency of the impacted areas was crumbly, and the gyri (ridges in the brain) appeared quite flattened out.
• At the microscopic level, profuse lesions with extensive haemorrhages were witnessed. A considerable number of neurons were found in various stages of degeneration and necrosis (cell death), accompanied by satellitosis (accumulation of glial cells around a neuron) and neuronophagia (destruction of nerve cells).
• The study also found cuffs formed by macrophages, plasma cells, and lymphocytes around the blood vessels. These perivascular cuffs were observed in the brain as well as the cerebellum.
• The cerebellum in particular, had significant edema (excess fluid) and substantial necrosis in the Purkinje cell layer (a type of neuron in the cerebellum), reflecting profound damage.

This detailed account of the clinical and pathological manifestations of equine leukoencephalomalacia provides significant insights into the disease condition instigated by the Fusarium moniliforme fungus, unveiling its severe consequences on the nervous system of the horses.