[Listeria enzootic in newborn lambs]

Area of Science:

• Veterinary Pathology
• Microbiology
• Epizootiology

Context:

• Listeriosis, caused by Listeria monocytogenes, poses a significant threat to livestock health.
• Meningo-encephalitic listeriosis has been observed in adult sheep, but its manifestation in newborn lambs requires detailed study.
• The enzootic nature of listeriosis in lambing flocks necessitates understanding transmission routes and clinical presentations.

Purpose:

• To conduct epizootiological, clinical, and pathomorphological investigations of a meningo-encephalitic form of listeriosis in newborn lambs.
• To describe the clinical signs and post-mortem findings associated with this specific listeriosis manifestation.
• To identify the causative agent, Listeria monocytogenes, in affected lambs.

Summary:

• Epizootiological, clinical, and pathomorphological studies detailed a meningo-encephalitic form of listeriosis in newborn lambs.
• Clinical symptoms and patho-anatomical/histological changes in the brain and organs of deceased lambs were documented.
• The outbreak was linked to silage in ewes' diets, with potential transmission via milk or prenatally. Listeria monocytogenes was isolated from lamb brain tissues.

Impact:

• This study elucidates the clinical and pathological characteristics of meningo-encephalitic listeriosis in newborn lambs, aiding in diagnosis.
• Findings suggest silage as a potential source of infection for ewes, leading to lamb mortality.
• Understanding transmission routes, including potential milk or prenatal infection, is crucial for implementing effective biosecurity measures in sheep flocks.