Spinal Cord and Peripheral Nerve Abnormalities of the Ruminant

Findings Related to Cerebrospinal Fluid and Central Nervous System Disorders in Small Ruminants-A Retrospective Study on Sheep and Goats

BACKGROUND

Small ruminants often suffer from central nervous system (CNS) disorders, and cerebrospinal fluid (CSF) analysis can be used as a diagnostic tool in this regard. In small animals and cattle, specific CSF patterns have been defined for specific disease categories. No data exist regarding CSF results obtained from small ruminants and their association with certain CNS diseases.

OBJECTIVES

The objective of this study was to retrospectively investigate CSF findings obtained from sheep and goats and to identify possible CSF patterns associated with disease categories.

METHODS

CSF samples and medical records from 44 sheep and 27 goats were included in this study. All animals were presented to the Veterinary Teaching Hospital Zurich of the Veterinary Teaching Hospital Zurich of the Vetsuisse Faculty of the University of Zurich between 2003 and 2016 and had either a confirmed CNS diagnosis or showed CSF changes without a specific CNS diagnosis.

RESULTS

Mixed mononuclear pleocytosis was the most common CSF pattern in sheep (25%), followed by monocytic pleocytosis (21%). Lymphocytic pleocytosis was most frequently found in goats (37%). In 75% of sheep and 56% of goats, infectious CNS diseases were diagnosed, with listeriosis being the most common infectious disease in both species, followed by parasitic disorders (nematodiasis and coenurosis).

CONCLUSIONS

The cytologic CSF patterns in small ruminants are mainly based on the increased presence of monocytic and lymphocytic cells with variable quantitative expression, whereas neutrophilic pleocytosis and cytoalbuminologic dissociation were rare findings. Infectious diseases of bacterial origin were the most common underlying causes for CSF alterations in sheep and goats, followed by parasitic disorders. The pleocytosis type is not helpful for differentiating disease types.

Pathologic features and molecular identification of parelaphostrongylosis in a sitatunga (Tragelaphus spekii)

We report the pathologic features, local inflammatory response immunophenotype, and molecular identification results of cerebral nematodiasis in a young sitatunga (Tragelaphus spekii) from Texas. To the authors' knowledge, this is the first report of cerebral nematodiasis by Parelaphostrongylus tenuis in a sitatunga, a bovid species introduced into the USA, and the first characterization of the local inflammatory response immunoprofile in this condition. A molecular identification method based on formalin-fixed and paraffin-embedded-polymerase chain reaction was described. These results contribute to knowledge on geographical distribution and host spectrum of P. tenuis, and highlight the relevance of this nematodiasis in naïve translocated or introduced bovid species into endemic areas.

Branquinho M, Sousa AC, Zen F, Maurina M, Raimondo S, Mendonça C, Atayde L, Geuna S, Varejão AS, Maurício AC. Establishment of a Sheep Model for Hind Limb Peripheral Nerve Injury: Common Peroneal Nerve

Thousands of people worldwide suffer from peripheral nerve injuries and must deal daily with the resulting physiological and functional deficits. Recent advances in this field are still insufficient to guarantee adequate outcomes, and the development of new and compelling therapeutic options require the use of valid preclinical models that effectively replicate the characteristics and challenges associated with these injuries in humans. In this study, we established a sheep model for common peroneal nerve injuries that can be applied in preclinical research with the advantages associated with the use of large animal models. The anatomy of the common peroneal nerve and topographically related nerves, the functional consequences of its injury and a neurological examination directed at this nerve have been described. Furthermore, the surgical protocol for accessing the common peroneal nerve, the induction of different types of nerve damage and the application of possible therapeutic options were described. Finally, a preliminary morphological and stereological study was carried out to establish control values for the healthy common peroneal nerves regarding this animal model and to identify preliminary differences between therapeutic methods. This study allowed to define the described lateral incision as the best to access the common peroneal nerve, besides establishing 12 and 24 weeks as the minimum periods to study lesions of axonotmesis and neurotmesis, respectively, in this specie. The post-mortem evaluation of the harvested nerves allowed to register stereological values for healthy common peroneal nerves to be used as controls in future studies, and to establish preliminary values associated with the therapeutic performance of the different applied options, although limited by a small sample size, thus requiring further validation studies. Finally, this study demonstrated that the sheep is a valid model of peripheral nerve injury to be used in pre-clinical and translational works and to evaluate the efficacy and safety of nerve injury therapeutic options before its clinical application in humans and veterinary patients.

Cerebrospinal nematodosis caused by Parelaphostrongylus species in an adult bull

A 2-y-old Brahman bull was presented with progressive hindlimb ataxia and paraparesis that led to recumbency. Postmortem examination revealed scattered pinpoint, red-brown foci within the brainstem and gray matter of the spinal cord, and a larger lesion within the spinal cord at the level of T13. Histology of the section of T13 contained cross-sections of nematodes consistent with Parelaphostrongylus tenuis. Evidence of inflammation was present in other affected areas of the spinal cord and brain. DNA extraction and nested PCR were performed, which demonstrated 98% identity and 100% coverage to both P. tenuis and P. andersoni. Our case highlights the utility of DNA sequencing in parasite identification.

Clinical findings from 104 cases of calving paralysis in dairy cows from Gippsland, Australia

Case History: Dairy cows recumbent following calving on farms in South Gippsland, Australia were examined during two 3-month seasonal calving periods in 2011 and 2012 as part of a larger study of 218 recumbent cows. A cohort of 104 cows diagnosed with calving paralysis following dystocia was derived from the larger group, which were examined with 3 days of becoming recumbent. A thorough medical and musculoskeletal clinical examination was performed on each cow including flexor-withdrawal and patellar reflex tests, and postural assessment in the lifted position, unless the facilities were not available. Cows were diagnosed with one or more neurological syndromes: sciatic, tibial paresis, obturator or femoral, based on clinical findings consistent with damage to these peripheral nerves or their nerve roots. Clinical Findings: Evidence of sciatic syndrome was found in 100/104 (96.2%) cows and 146/172 (84.9%) affected hind limbs either as the sole neuropathy or in combination with tibial paresis, obturator or femoral syndromes. Pelvic damage was also present in 3/104 (2.8%) cows. Obturator syndrome was diagnosed in 30/104 (29%) cows and 45/172 (26.2%) affected hind limbs but not apparently as the sole reason for the recumbency. Femoral syndrome occurred in 16/104 (15.4%) cows and 21/172 (12.2%) affected hind limbs and was the only syndrome recorded in one cow. Clinical Relevance: Sciatic syndrome was the most common neurological syndrome observed in cows with calving paralysis. The other major nerves arising from the lumbo-sacral plexus were also affected and the various syndromes associated with damage to these nerves or their ventral nerve roots occurred in many combinations. Calving paralysis should be thought of as a paresis or paralysis resulting from damage to the ventral nerve roots of the lumbo-sacral plexus as any of the nerves originating from this plexus can be damaged during dystocia either individually or in combination with other nerves from the plexus.

Survival associated with cerebrospinal fluid analysis in downer adult dairy cows: A retrospective study (2006-2014)

Background

Threshold values for total nucleated cell count (TNCC) and protein concentration in cerebrospinal fluid (CSF) of downer dairy cows suggestive of a spinal cord lesion were recently published.

Objectives

Determine short‐ and long‐term survival of downer cows that underwent CSF analysis using the reported threshold values. Evaluate the prognostic value of these threshold values to predict short‐ and long‐term survival.

Animals

Two hundred and fourteen downer adult dairy cows that underwent CSF analysis during hospitalization at the Centre Hospitalier Universitaire Vétérinaire (CHUV) of the Université de Montréal.

Methods

Retrospective study. Medical records of downer adult dairy cows presented to the hospital between January 2006 and October 2014 for which CSF analysis results were available were studied. Short‐term (discharge from hospital) and long‐term (completion of lactation) survival were determined and compared in accordance with CSF TNCC and protein concentration, using a Chi‐square test.

Results

Cows with CSF TNCC and/or protein concentration above the threshold values had a significantly lower short‐term survival rate (P = .02). The odds of nonsurvival of cows with one or both CSF values above the threshold values was 2.16 times higher than the odds for cows with values under the threshold values. CSF TNCC >4.5 cells/μL had sensitivity and specificity of 17.3% (95% CI: 10.7%‐25.7%) and 92.3% (95% CI: 85.4%‐96.6%), respectively, for predicting short‐term nonsurvival. CSF protein concentration >0.39 g/L had sensitivity and specificity of 20.9% (95% CI: 13.7%‐29.7%) and 91.4% (95% CI: 84.2%‐96.0%), respectively.

Conclusions

CSF analysis above threshold values used in this study is associated with increased odds of short‐term nonsurvival.