A tremorgenic mycotoxicosis of cattle caused by maize sprouts infested with Aspergillus clavatus

An outbreak of disease affecting a herd of 16 dairy cattle which were fed mouldy, sprouted maize is described. Eight of the cattle were affected, 5 of which died. The clinical signs included muscular tremors, hypersensitivity, ataxia, anorexia and salivation. Aspergillus clavatus was the only fungus isolated from the sprouts. Clinical signs that were indistinguishable from those in the field outbreak were reproduced by dosing the mouldy maize sprouts to a steer and a sheep, and by dosing another sheep with maize inoculated with a pure culture of A. clavatus isolated from the mouldy maize on the farm. Light microscopical examination revealed neuronal degeneration and necrosis in the midbrain, medulla oblongata and spinal cord of all 3 of these animals. The disease is clinically and pathologically indistinguishable from the disease caused by the ingestion of sorghum beer residue, and in certain respects it is similar to toxicoses caused by the ingestion of wheat sprouts and malt sprouts infested with A. clavatus.     

A fodder mycotoxicosis of ruminants caused by contamination of a distillery by-product with Aspergillus clavatus

Cattle and sheep, grazed successively on the same pasture and given the same supplementary feeding, developed ataxia and several animals became recumbent. Three cattle died within two weeks and the worst affected sheep were killed for laboratory examination. The supplementary diet which consisted largely of a distillery by-product, malt culms, was submitted for mycological examination and fed to two housed lambs. Aspergillus clavatus was cultured from the culms, and both the affected sheep and the housed lambs showed cerebrospinal degenerative changes. The clinical signs and neuropathology were closely similar to a mycotoxicosis, attributed to A clavatus, which is seen infrequently in cattle in France, Bulgaria, South Africa and China.     

Spinal muscular atrophy in Braunvieh calves]

Clinical, neurophysiological and histopathological findings of sixteen cases of spinal muscular atrophy in calves are described. The first clinical signs usually were noticed at 2-6 weeks of age. The animals showed weakness in the hindquarters, trembling and ultimate recumbency. There was a marked muscular atrophy in all four extremities. In addition, secondary bronchopneumonia was evident in 11 cases. Histopathological lesions consisted of degenerative changes in the neurons of the ventral horns and the axons of the spinal cord as well as degeneration of nerve axons in the extremities. Neurophysiological measurements revealed spontaneous activity in the muscles of the limbs. The conditions is autosomal recessive. So far 11 bulls have been identified and excluded from breeding.     

A survey of more than 11 years of neurologic diseases of ruminants with special reference to transmissible spongiform encephalopathies (TSEs) in Greece

The first cases of scrapie were detected in Greece in a flock of sheep in October 1986. All the animals of the affected flock and all sheep in two flocks that were in contact were killed and buried. A systematic investigation of all available cases with signs indicating a neurological disease started in sheep and goats in late 1986, as well as in cattle in 1989. The investigation was based on clinical examination, necropsy or macroscopical examination of the brain and viscera, and histological examination of the brain in all animals except those with coenurosis. Histological examinations of specimens from the spinal cord and other tissues, and if considered necessary bacteriological, toxicological and serological examinations were also carried out. In October 1997, scrapie was diagnosed in sheep of a second flock (a mixed flock of sheep and goats), grazing in a pasture close to the place where scrapie was initially detected. All animals of the second flock were also killed and buried. Diagnosis in the first flock was based on clinical signs and histological lesions, and in the second immunoblotting was also used. Distinctive lesions of scrapie were found in the brain and/or the spinal cord of eight sheep with clinical signs from the two flocks. The lesions were revealed in the brain stem and/or in the cervical spinal cord, and tended to be symmetrical. In one sheep, severe lesions in the cortex of cerebral hemispheres and of the cerebellum were also found. In the brain of two sheep from the second flock the pathological isoform of PrP protein was detected. Despite the eradication scheme applied, scrapie in sheep reappeared after 11 years in a place close to where it occurred initially. This may indicate that the effectiveness of the eradication scheme implemented was not adequate and additional approaches may be needed.     

Tremorgenic syndrome in a cattle herd after feeding silage contaminated with A. clavatus

The clinical signs, pathological and laboratory findings of cattle suffering from a tremorgenic syndrome are described. Animals on a farm with a total of 22 cows, 18 heifers and 9 calves were fed mouldy grass and spent malt-grain silage. Five heifers were affected with muscular tremor, hyperexcitability and hypersensitivity. They were ataxic or in sternal recumbency, while their appetite remained normal. Haematology and blood chemistry in two heifers as well as cerebrospinal fluid from one sick animal were unremarkable. The pathological examination of one animal brought no macroscopic changes to light. Histological examination, however, revealed the degeneration of motor neurones in the midbrain, brain stem and spinal cord. Analysis of a silage sample provided evidence of the presence of Aspergillus clavatus, a mould capable of producing neurotoxic tremorgenic mycotoxins. Epidemiology, clinical findings, pathology and microbiological examination suggest that the five cattle were suffering from neuromycotoxicosis.     

Ataxia and weakness associated with fourth ventricle vascular anomalies in two horses

Two adult horses with progressive neurologic signs were examined clinically and at necropsy. Both horses had signs of progressive ataxia and weakness, clinically diagnosed as spinal cord in origin. Differential diagnoses for cervical spinal ataxia in horses included cervical vertebral malformation, equine degenerative myeloencephalopathy, equine herpes-virus-I myeloencephalopathy, and equine protozoal myeloencephalopathy. Necropsy findings in both horses were similar and consisted of a large hematoma in the fourth ventricle, with upward compression of the cerebellum and downward compression of the pons and rostral portion of the medulla.     

Intramedullary spinal cord damage associated with intervertebral disk material in a dog

Intervertebral disk extrusions into the spinal cord are rarely reported in veterinary medicine, and only necropsy findings are described in previous reports. It is hypothesized that a disk lesion results in forceful injection of disk material into the spinal cord. In the 3-year-old Miniature Doberman Pinscher of our report, acute clinical signs and results of magnetic resonance imaging were consistent with this disease and helped determine the extent and character of the lesions. Alteration in the appearance of the nucleus pulposus was important in determining that intervertebral disk disease may have been present in this dog. However, a definitive diagnosis of intramedullary disk extrusion can be made only via histologic examination of a biopsy specimen or at necropsy. The dog improved substantially after surgical decompression of the spinal cord, and histologic findings in a biopsy specimen of material found within the spinal cord were consistent with mature degenerate intervertebral disk material.     

Degenerative spinal disease in large felids.

Degenerative spinal disorders, including intervertebral disc disease and spondylosis, seldom occur in domestic cats. In contrast, a retrospective study of 13 lions (Panthera leo), 16 tigers (Panthera tigris), 4 leopards (Panthera pardis), 1 snow leopard (Panthera uncia), and 3 jaguars (Panthera onca) from the Knoxville Zoo that died or were euthanatized from 1976 to 1996 indicated that degenerative spinal disease is an important problem in large nondomestic felids. The medical record, radiographic data, and the necropsy report of each animal were examined for evidence of intervertebral disc disease or spondylosis. Eight (three lions, four tigers, and one leopard) animals were diagnosed with degenerative spinal disease. Clinical signs included progressively decreased activity, moderate to severe rear limb muscle atrophy, chronic intermittent rear limb paresis, and ataxia. The age at onset of clinical signs was 10-19 yr (median = 18 yr). Radiographic evaluation of the spinal column was useful in assessing the severity of spinal lesions, and results were correlated with necropsy findings. Lesions were frequently multifocal, included intervertebral disc mineralization or herniation with collapsed intervertebral disc spaces, and were most common in the lumbar area but also involved cervical and thoracic vertebrae. Marked spondylosis was present in the cats with intervertebral disc disease, presumably subsequent to vertebral instability. Six of the animals' spinal cords were examined histologically, and five had acute or chronic damage to the spinal cord secondary to disc protrusion. Spinal disease should be suspected in geriatric large felids with decreased appetite or activity. Radiographic evaluation of the spinal column is the most useful method to assess the type and severity of spinal lesions.     

Degenerative myelopathy in a German shepherd

A 9-year-old male German Shepherd had marked stumbling, staggering and weakness in both rear limbs. Pelvic radiographs revealed only mild hip dysplasia, while survey spinal radiographs and a myelogram revealed only areas of possible pachymeningitis. Results of CSF analysis were normal. Degenerative myelopathy was suspected, but a mitogen response assay failed to confirm this diagnosis. Another mitogen response assay, performed several months later, again failed to indicate degenerative myelopathy as the cause of clinical signs. The dog's condition worsened and the animal was euthanized. At necropsy, classic histopathologic lesions of degenerative myelopathy were noted in the thoracic spinal cord.     

MAGNETIC RESONANCE IMAGING APPEARANCE OF SUSPECTED ISCHEMIC MYELOPATHY IN DOGS

Ischemia and infarction of the spinal cord is a known cause of acute spinal injury in dogs. Currently, the diagnosis of spinal cord infarction in small animals is based on history, clinical signs, and the exclusion of other differentials with radiography and myelography. It is a diagnosis only confirmed through necropsy examination of the spinal cord. The aim of this paper is to describe the Magnetic resonance imaging (MRI) findings of the spinal cord of dogs with suspected spinal cord infarcts to utilize this technology for antemortem support of this diagnosis. This retrospective study evaluated the spinal MR examinations of 11 dogs with acute onset of asymmetric nonpainful myelopathies. All patients except one (imaged at 2 months) were imaged within 1 week of clinical signs and managed conservatively with minimal medical and no surgical intervention. They were followed clinically for a minimum of 4 months after discharge. MR findings in all dogs were characterized by focal, intramedullary, hyperintense lesions on T2-weighted images with variable contrast enhancement similar to what is reported in humans. Though it could not be used to diagnose spinal cord infarction definitively, MRI was useful in excluding extramedullary spinal lesions and supporting intramedullary infarction as a cause of the acute neurologic signs. Together with the history and clinical examination findings, MRI is supportive of a diagnosis of spinal cord infarction.     

Lesions in bovine progressive degenerative myeloencephalopathy ("Weaver") of Brown Swiss cattle

Gross changes and other necropsy findings in 36 purebred Brown Swiss cattle affected with bovine progressive degenerative myeloencephalopathy were nonspecific. Primary microscopic lesions were confined to the central nervous system, specifically the white matter of the spinal cord, axons in some brainstem nuclei, and Purkinje cells of the cerebellar cortex. Spinal cord lesions involved only the white matter and consisted of axonal degeneration, loss of axons and myelin, and status spongiosus. Axonal degeneration was characterized by swelling and fragmentation of the axoplasm or formation of large, discontinuous swellings referred to as spheroids. Lesions were qualitatively similar at all levels, but quantitatively dissimilar in the same funiculi at different levels. Both ascending and descending fibers were involved but correlation to specific fasciculi was not evident. Lesions always were most severe in thoracic spinal cord segments. Little or no astroglial response, no inflammatory response, and no involvement of gray matter were observed in the spinal cord. Cerebellar lesions were limited to selective degeneration and loss of Purkinje cells and occasional swelling of Purkinje cell axons (torpedos) in the granular layer of the cerebellar cortex. Brainstem lesions were inconsistent and limited to occasional axonal swelling in brainstem nuclei. The pathogenesis of bovine progressive degenerative myeloencephalopathy is unknown and possible mechanisms were discussed. The disease exhibits a familial pattern in Brown Swiss cattle and may be hereditary. Extraneural lesions were considered secondary to central nervous system lesions.     

Fibrocartilaginous embolism and ischemic myelopathy in a four month old German shepherd dog.

Clinical signs and postmortem findings are described in a four month old German Shepherd dog with fibrocartilaginous embolism of the spinal cord. Ischemic myelopathy involved spinal cord segments C7 to L1. No evidence of degeneration or herniation of intervertebral discs was found at necropsy.     

METRIZAMIDE MYELOGRAPHY IN FIVE DOGS AND TWO CATS WITH SUSPECTED SPINAL CORD NEOPLASMS

Metrizamide myelography was used in five dogs and two cats with signs of spinal cord disease. The history, clinical signs, cerebrospinal fluid examination, and myelography supported a presumptive diagnosis of spinal cord neoplasia in all seven animals. Myelography demonstrated a deviation of the subarachnoid space in each of them. Five of the animals had an expansile intramedullary spinal cord lesion causing thinning and peripheral deviation of the subarachnoid space. Two had extramedullary lesions causing a central deviation of the subarachnoid space. Spinal cord tumors in six of the seven animals were confirmed by necropsy or surgical excision and histopathologic examination. In the seventh animal, a spinal cord fungal grapuloma was diagnosed by necropsy.     

Neospora caninum associated with epidemic abortions in dairy cattle: The first clinical neosporosis report in Turkey

Neospora caninum, a protozoan parasite, has been considered as one of the most important etiological agents responsible for abortion in dairy cattle throughout the world since it was first identified in dogs in 1988. In this report, characteristics of neosporosis, detected in a dairy cow ranch having epidemic abortions as high as 18.4%, were described. Blood samples were collected from 25 infertile or aborted dairy cattle, 6 calves born in 2006 and 40 heifers that were born in 2005 and raised in the same ranch. Necropsy was conducted in a 20-day-old Simmental calf that exhibited neurological signs including incoordination, head shaking, hyperextension in forelimbs and hindlimbs and tremor. The seroprevalance in aborted or infertile dairy cattle, heifers, and calves was 60%, 40%, and 33.3%, respectively. The mothers of seropositive two calves including clinically affected calf and its dam were N. caninum seropositive. In immunoperoxidase examinations, N. caninum antigen immunopositivity was observed in the degenerative and necrotic neurons in the brain, cerebellum as well as neurons in dorsal root ganglia of the cervical and thoracic regions of the spinal cord. In the heart, myocytes and Purkinje cells exhibited granular and linear patterns of immunoreactivity. Striated myofibers around the eyeball also showed immunolocalization for N. caninum antigen. Ultrastructurally, tachyzoites with typical apical complex, rhoptries and double-layered parasitic membrane were detected in the brain and heart sections. In conclusion, this report described clinical neosporosis for the first time in Turkey with tissue localization of the causative agents. This scientific communication also discusses the possible impact of cattle neosporosis by clinical, serologic and pathologic evidences collected from the survey of calves born in two successive generations in a ranch.     

Congenital tremor in Holstein Friesian-cattle.

In a female family line of Holstein-Friesian cattle a series of trembling calves was born within a period of ten years. All trembling animals were male; female calves appeared normal. At necropsy of one calf severe degenerative lesions of spinal cord and brain white matter were observed. Both myelin and axons were lost and some macrophages occurred within digestion chambers. Obviously degenerated neurones were not found. The lesion was interpreted as a single recessive sex-linked hereditary trait.     

Are ovine fenugreek (Trigonella foenum‐graecum) staggers and kangaroo gait of lactating ewes two clinically and pathologically similar nervous disorders?

Fenugreek staggers has occurred in sheep in Victoria, as both an acute and a chronic syndrome. Signs included quadraparesis, a high stepping fore limb gait and a 'bunny-hopping' hind limb gait. Changes consistent with acute oedema were found in the brain and spinal cord of acute cases, and Wallerian degeneration in the peripheral nerves of chronic cases. Kangaroo gait occurred in ewes in New South Wales, and the clinical signs and microscopic changes were remarkably similar to those of fenugreek staggers. Although the diet associated with each is different the causal agent may be the same.     

Progressive encephalomyelopathy and cerebellar degeneration in 10 captive-bred cheetahs

Progressive ataxia, with head tremor, developed in 10 captive-born cheetah cubs under six months of age. The condition was usually preceded by coryza and an ocular discharge. Initially the ataxia and weakness affected the hindquarters, then the forelegs, and head tremor developed later. Significant pathological changes were confined to the central nervous system. There was widespread Wallerian degeneration in the funiculi of the spinal cord (except those in the dorsal columns), in the medulla and in the cerebellum. In the cerebellum there was degeneration of Purkinje cells and of the molecular and granular cell layers. There was chromatolysis in the Purkinje cells, the ventral horn cells of the spinal cord and in the neurons of the lateral vestibular nucleus. The olivary nucleus was necrotic. There were foci of inflammatory cells in the molecular layer of the cerebellum and in the medulla. The cause of the disease remains unknown.     

A retrospective study of spinal cord lesions in goats submitted to 3 veterinary diagnostic laboratories

A retrospective study of spinal cord lesions in goats was conducted to identify the range of lesions and diseases recognized and to make recommendations regarding the best tissues to examine and tests to conduct in order to maximize the likelihood of arriving at a definitive etiologic diagnosis in goats with clinical signs referable to the spinal cord. Twenty-seven goats with a spinal cord lesion were identified. The most common lesion recognized, in 13 of 27 goats, was degenerative myelopathy. Eight goats with degenerative myelopathy were diagnosed with copper deficiency. Non-suppurative inflammation due to caprine arthritis encephalitis virus, necrosis due to parasite larvae migration, and neoplasia were each diagnosed 3 times. Based on these findings, it is recommended that, in addition to careful handling and histologic examination of the spinal cord, samples of other tissues, including the brain, liver, and serum, be collected for ancillary testing if warranted.     

Intraspinal epidermoid cyst in a dog

A 2-year-old female Rottweiler was examined because of progressive gait deficits consistent with transverse myelopathy between the T2 and L3 spinal cord segments. Myelography confirmed an intramedullary spinal cord lesion between T13 and L1, so the dog was euthanatized. At necropsy, an intramedullary epidermoid cyst was confirmed in the T13 and L1 spinal cord segments. The epidermoid cyst probably resulted from a congenital cause.     

Congenital tremor in Holstein Friesian‐cattle

Summary

In a female family line of Holstein‐Friesian cattle a series of trembling calves was born within a period of ten years. All trembling animals were male; female calves appeared normal At necropsy of one calf severe degenerative lesions of spinal cord and brain white matter were observed Both myelin and axons were lost and some macrophages occurred within digestion chambers. Obviously degenerated neurones were not found The lesion was interpreted as a single recessive sex‐linked hereditary trait.