Nervous form of listeriosis in sheep in Bosnia and Herzegovina

Abstract

This paper describes the occurence of listeriosis in silage fed domestic sheep of the Pramenka type. The aim was to investigate causes of death of animals with previously manifested nervous signs. According to the Law on Veterinary Medicine in Bosnia and Herzegovina, the brain of sheep showing nervous signs of illness must be examined with suspicion on Listeria monocytogenes infection. The disesase occured in the region of Eastern Bosnia in February, 2009. The sheep affected were adult, gravid females. All sheep affected by disease shared similar clinical signs: dyspnea, increased heart rate, circling, staggering, torticollis and inappetence. No abortions of gravid sheep were noted. All simptoms were lasting for 3 to 4 days with lethal outcome and mortality of 5%. The administration of procaine benzylpenicillin showed no results. The necropsy of death sheep revealed encephalitis. Histopathologically, multifocal microabscesses containing mainly degenerated and viable neutrophils, perivascular accummulation of lymphocytes and plasma cells with some macrophages and neutrophils, and multifocal fibrinous microthrombi in the lumina of the blood vessels were observed in the brain tissue. Also, neuronal degeneration and small microglial accummulation were noted. Microbiologically, Listeria monocytogenes was isolated from the brain tissue.