An Outbreak of Meningoencephalomyelitis in a Sheep Flock

Twenty sheep of a mixed flock in Karaj, Meshkin Dasht area, were died in a period of two weeks (February 20 - March 5, 2009). They had signs of respiratory system disorders, unconsciousness, circling, convulsion and finally paralysis. The elapsed time between the first sign of disease, to death was one hour to three days. Respiratory disorder, hemi paralysis and V-XII cranial nerve dysfunctions were observed on the clinical examinations of a four-month replacement lamb and a four years-old ewe. Environmental inspection indicated spoiled silage in an earthen pit. Hematological, clinical biochemistry, microbiological and pathological studies on four months old sheep were with an approach to serosal membranes hyperemia, fibrinonecrotic enteritis and microabscesses presence in brain stem and liver. While isolated Listeria monocytogenes from lung tissue and cerebrospinal fluid, indicated bacteriemia and septicemia. Whereas in the case of four years-old ewe, microabscesses in the brain stem accompanied by isolation of Listera monocytogenes from cerebrospinal fluid, which is characteristic of nervous listeriosis. The appearance of microabscesses, both in brainstem and cervical spinal cord of both animals, is a rare case which its occurrence is indicative of Listeric meningoencephalomyelitis. An unawareness of silage production and management in the mentioned flock, that was dependent on pasture grazing, resulted in detriment. Attention to the public health issues of listeriosis, knowledge translation and a precise inspection could avoid the outbreak of the same cases.