Visna-like disease in a Minnesota sheep

Area of Science:

• Veterinary Neurology
• Pathology
• Ovine Diseases

Background:

• Visna is a serious neurological disease affecting sheep.
• It is caused by a lentivirus and can lead to progressive neurological signs.
• Diagnosis in the United States is uncommon, making it a challenging differential.

Observation:

• A 4-year-old Mouflon ram presented with neurological symptoms.
• The ram was part of a flock in Minnesota.
• Histologic examination revealed a unique pattern of brain lesions.

Findings:

• The observed histologic lesions were characteristic of visna-like disease.
• This diagnosis was confirmed based on the specific neuropathological findings.
• The unique lesion distribution was key to identifying the disease.

Implications:

• This case underscores the need to include visna in the differential diagnosis for sheep with neurological disorders.
• It suggests that visna may be underdiagnosed in the United States.
• Further surveillance and diagnostic efforts for ovine lentiviruses are warranted.