Listerial Encephalitis Research Articles

Immunohistochemical expression of MMP–2 and MMP–9 in the brain tissue of sheep naturally infected with Listeria monocytogenes and relationship with cell death in the Listerial encephalitis

Immunohistochemical expression of MMP–2 and MMP–9 in the brain tissue of sheep naturally infected with Listeria monocytogenes and relationship with cell death in the Listerial encephalitis

Ovine listerial encephalitis: a common diagnosis in the first quarter of 2023.

Ovine listerial encephalitis: a common diagnosis in the first quarter of 2023.

Northern Ireland disease surveillance report for January to March 2014

Listerial encephalitis in adult cattleOxalate nephrosis in Zwartble ewes and lambsHistomonosis in chickensFeline tuberculosis caused by Mycobacterium bovisThese are among matters discussed in the Northern Ireland animal disease surveillance quarterly...

Listerial encephalitis with abscess formation and cervical myelitis in an immunocompetent adult

Listerial encephalitis with abscess formation and cervical myelitis in an immunocompetent adult

Clinical diagnosis of ovine listeriosis

Listerial encephalitis is essentially a localised infection of the brainstem that occurs when Listeria monocytogenes ascends the trigeminal nerve. Clinical signs vary according to dysfunction of the damaged nerve nuclei. This article uses high quality video recordings of sheep with suspected listeriosis to illustrate this range of clinical signs to assist veterinary practitioners in their clinical investigations. Cerebrospinal fluid sampling is a simple and safe procedure in small ruminants and yields useful information in the differential diagnosis of neurological diseases in small ruminants.

Pathological and epidemiological investigations into listerial encephalitis in sheep

Three outbreaks of encephalitis caused by Listeria monocytogenes were investigated in the migratory flocks of sheep in Punjab, India. Sixty-nine sheep were affected out of 930 animals (875 sheep and 55 goats) during these outbreaks, with cumulative morbidity, mortality and case fatality rate of 7.89, 7.08 and 89.85%, respectively. Incidence of disease was low in sheep below 6 months of age with cumulative morbidity and mortality rate of 3.75% as compared to 9.5 and 8.3%, respectively in sheep above 6 months of age. Case fatality was highest (100%) in young sheep below 6 months of age when compared to 88.3% in adult sheep above 6 months of age. Clinical signs included circling movements, unilateral facial paralysis, twisting of neck, stiffening and opisthotonus, blindness, corneal opacity and retention of food in mouth. Histopathologically, extensive perivascular cuffing, microabscesses and meningitis were observed in medulla oblongata, pons and anterior part of spinal cord. In few cases, microabscesses were also present in liver. Cerebrospinal fluid revealed higher concentration of total proteins with increase in globulins. Isolation of L. monocytogenes was made from hind brain and anterior part of spinal cord using cold enrichment method. There was no symptom of disease in the goats.

Occurrence of the ear-mite Raillietia auris in cattle in Austria

We describe here the first documented case in Austria of the cattle ear mite Raillietia auris in a four-year-old dairy cow. The cow was mildly depressed, and keratoconjunctivitis was diagnosed in both eyes with Horner’s syndrome in the left eye. The animal showed a mild head tilt to the left and a generalized ataxia with a tendency to move to the right side, which became exacerbated if the animal was blind-folded. Head pressing to the right side, dysphagia and a dropped jaw were also observed. Numerous rather mobile ear mites were observed at necropsy in the basal part of the left ear canal. The clinical significance of the cattle ear mite is uncertain and the clinical signs could have been caused by listerial encephalitis, which was also confirmed histologically in this case.

Pathology of listerial encephalitis in chickens in Japan.

Neural signs (torticollis, drowsiness) and mortality were observed in five chickens of a native chicken flock (reared for meat) that included 450 male birds on a farm that had 2300 native chickens and 1120 layers. Histologic lesions were observed in the medulla oblongata, optic lobe, cerebellum, and spinal cord of the affected birds. The lesions, which were most severe in the medulla oblongata, were massive abscesses with rarefaction (demyelination and malacia) of the parenchyma with gram-positive bacteria. The degenerative and necrotic areas were characterized by fibrin thrombosis, hemorrhages, and congestion in the blood vessels. Immunohistochemically, the bacteria positive for L. monocytogenes antigen were observed in the medulla oblongata, cerebellum, and spinal cord. Ultrastructurally, the small rod-shaped and thin-cell-walled bacteria were observed in the parenchyma of the medulla oblongata. Listeria monocytogenes (serotype 4b) was isolated from the medulla oblongata and spinal cord. The pathogenesis of listerial encephalitis in chickens was discussed.

Investigation of a listeriosis epizootic in sheep in New York state

Abstract Objective To investigate potential sources of an epizootic of listerial encephalitis, using molecular diagnostic and typing methods. Sample Population A flock of about 655 sheep. Procedure An epizootiologic investigation was performed. Clinical, feed, and environmental samples were tested for Listeria monocytogenes, using polymerase chain reaction and culture methods; recovered isolates were “fingerprinted,” using an automated ribotyping system. Results Listeria monocytogenes was recovered from brain specimens of 7 sheep with clinical signs of listerial encephalitis. All clinical isolates had fingerprints identical to those of isolates from farm equipment used to transport silage. Corn silage, which was not fed to the sheep, also contained L monocytogenes of the same pattern type as defined by ribotyping. Listeria monocytogenes was not isolated from the stored haylage designated for feeding the sheep (the cut-off point for isolation being < 102 colony-forming units/g). Conclusions Corn silage was implicated as the source of a listeriosis epizootic. It appears to have cross-contaminated the haylage destined for the sheep during handling with a front-end loader. Suspension of silage feeding coincided with cessation of listeriosis cases. Clinical Relevance Use of advanced molecular techniques can help to identify the sources and restrict the scope of an epizootic. In epizootics, a single L monocytogenes strain can lead to infection of multiple animals, with rapid progression of the disease. (Am J Vet Res 1997;58:733–737)

Diagnosis and epidemiological association of Listeria monocytogenes strains in two outbreaks of listerial encephalitis in small ruminants.

Two outbreaks of epizootic listerial encephalitis, one in sheep and one in goats, were investigated through pathology, microbiology, and DNA amplification-based techniques. Efforts were made to survey the diversity of Listeria monocytogenes strains in the silage consumed by affected animals and to verify the causal relationship between silage and disease outbreak. In both outbreaks, L. monocytogenes was isolated from silage and brain tissue samples. Random amplified polymorphic DNA patterns revealed two distinct L. monocytogenes strains, one of which was identical to the sheep brain isolate, in the silage associated with the outbreak in sheep. Three brain isolates and one silage isolate, all of which had different random amplified polymorphic DNA patterns, were found in the outbreak involving goats. All isolates from both outbreaks were indistinguishable in an in vitro assay for cell-to-cell spread and growth in macrophages. All brain isolates from the goat outbreak had identical intracellular ActA patterns, which were different from the pattern for the silage isolate. While the sheep brain isolate had an ActA pattern different from that of the corresponding silage isolate, the patterns for the brain isolates from the two outbreaks were not identical. This survey demonstrates the diversity of L. monocytogenes in silage and suggests the existence of one or more selective processes by which certain strains are more prone to give rise to disease.

Ovine listerial encephalitis: analysis, hypothesis and synthesis.

Analysis of field data suggested that listerial encephalitis in sheep was most common in winter and early spring in the age groups of sheep which would be cutting, changing and possibly losing teeth. It was hypothesised that under these conditions ingested Listeria monocytogenes could reach the fine dental terminals of the trigeminal nerve causing an ascending neuritis and encephalitis. Experimental inoculation of organisms into the dental pulp demonstrated the feasibility of this route of infection. Histological encephalitis was evident six days after inoculation but the incubation period to clinical neurological disease was at least three weeks.