Neurological diseases in cattle caused by plants and mycotoxins in Santa Catarina state, Brazil / Enfermidades neurológicas em bovinos causadas por plantas e micotoxinas no estado de Santa Catarina

This study described the epidemiological and clinical-pathological aspects of 25 outbreaks of neurological diseases in cattle caused by plants and mycotoxins in Santa Catarina state. Six of them were due to Sida carpinifolia poisoning, five to Solanum fastigiatum, five to Phalaris angusta, three to Claviceps paspali, three to Claviceps purpurea, and three outbreaks were of unknown etiology. The clinical signs observed in the affected cattle were mild to severe and characterized by generalized muscle tremors, incoordination, hypermetria, wide-based stance, intentional head tremors, dull staring eyes, and frequent ear twitching, with convulsions in some cases. At necropsy, lesions were observed only for P. angusta poisoning, characterized by gray-greenish discoloration in thalamus and midbrain. Microscopically, rarefaction and/or disappearance of Purkinje neurons with substitution by Bergmann cells were observed for S. carpinifolia and S. fastigiatum poisoning. For P. angusta poisoning, thin granular brown-yellowish pigment was observed in the cytoplasm of some neurons. Gross and microscopic findings were not observed in three outbreaks of tremorgenic disease of unknown etiology. Experiments conducted with leaves, flowers and seeds of Ipomoea indivisa and Ipomoea triloba, as well as with maize and soybean residues contaminated with Ipomoea spp. did not reproduced clinical signs.(AU)

Descrevem-se os aspectos epidemiológicos e clinico-patológicos de 25 surtos de enfermidade neurológica em bovinos no estado de Santa Catarina causadas por plantas e micotoxinas. Destes, seis corresponderam a intoxicação por Sida carpinifolia, cinco por Solanum fastigiatum, cinco por Phalaris angusta, três por Claviceps paspali, três por Claviceps purpurea e três surtos de etiologia não definida. Os sinais clínicos observados nos bovinos afetados eram de intensidade leve a acentuada e caracterizados por tremores musculares generalizados, incoordenação, hipermetria, aumento da base de sustentação, balanço contínuo de cabeça, olhar atento e movimentos frequentes de orelhas, e em alguns surtos convulsões. Por meio de necropsia foram observadas alterações somente na intoxicação por P. angusta as quais caracterizaram por coloração cinza-esverdeada no tálamo e mesencéfalo. Na histologia, rarefação e/ou desaparecimento de neurônios de Purkinje com substituição por células de Bergmann foram observadas na intoxicação por S. carpinifolia e S. fastigiatum. Na intoxicação por P. angusta foi observado no citoplasma de alguns neurônios do tronco encefálico com pigmentação finamente granular marrom-amarelada. Nos três surtos de enfermidade tremorgênica com etiologia não definida não foram observadas lesões macroscópicas e microscópicas. Experimentos com folhas, flores e sementes de Ipomoea indivisa e Ipomoea triloba e resíduos de milho e soja contaminados com sementes destas duas plantas não produziram alterações clínicas.(AU)

Allergenicity of Gramineae bee-collected pollen is proportional to its mass but is highly variable and depends on the members of the Gramineae family

BACKGROUND: Gramineae bee-collected pollen is identified as being at the origin of allergic accidents but the biological potency of Gramineae bee-collected pollen is not well known. Cereal grasses (e.g., Zea) and European wild forage grasses (FG) are contained in bee-collected pollen. METHOD: In this experiment, Zea-mass and FG-mass were identified in bee pollen mass and the proportion of Zea and of FG was calculated using the bee pollen melissopalynology spectrum. Skin reactivity to Zea and to FG were assessed by measuring wheal diameters (W) from skin prick tests using three serial dilutions of bee-collected pollen on 10 allergic patients to Gramineae, in order to calculate the relationship between Zea mass (Masszea) or FG mass (MassFG) in bee pollen and skin reactivity. RESULTS: The linear function Log10(WFG) = 0.24(Log10(MassFG)) + 0.33 (R = 0.99) was established using a bee pollen sample with 0.168 mg of FG pollen per mg. The linear function Log10(Wzea) = 0.23(Log10(Masszea)) + 0.14 (R = 0.99) was established using a bee pollen sample with 0.983 mg of Zea pollen per mg. Gramineae allergens seem to be little altered by bee secretions. Gramineae bee pollen retains its allergenic capacity but it depends on the members of the Gramineae family. CONCLUSIONS: To our knowledge this is the first time it has been shown that skin reactivity to Gramineae is proportional to the absolute Gramineae mass contained in the bee-collected pollen and that it depends on the members of the Gramineae family

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[Yellow oat grass intoxication in horses: Pitfalls by producing hay from extensive landscapes? A case report]. / Goldhafer-Intoxikation bei Pferden: Wie sicher ist die Heuqualität von extensiven Standorten? Ein Fallbericht.

Vitamin-D intoxication by yellow oat grass is often reported under the syndrome of enzootic calcinosis in ruminants in the upper regions of the Alps. The intake of Trisetum flavescens in ruminants and horses induces calcification of soft tissue, including vessels, tendons and ligaments, lung, heart and kidneys. Clinical symptoms, including a reluctance to move, inappetence, body-weight loss and impaired organ function, are frequently observed. To date, there are only a very few case reports about yellow-oat-grass intoxication in horses. The present case report describes Vitamin-D intoxication by yellow oat grass in a riding stable in Thuringia, Germany. The horses, which were fed hay with a 50% contamination of Trisetum flavescens, displayed symptoms, including inappetence, body-weight loss, colic, polydipsia and polyuria. The hay, contaminated with Trisetum flavescens, was harvested from an extensively cultivated landscape according to the European Fauna-Flora-Habitat (FFH)-directive. The present case report demonstrates the pitfalls in producing hay from extensively used landscapes and indicates some peculiarities of Vitamin-D metabolism in horses.

[Fractional photothermolysis. Treatment of post-inflammatory hyperpigmentation following meadow grass dermatitis]. / Fraktionierte Photothermolyse. Behandlung der postinflammatorischen Hyperpigmentierung nach Wiesengräserdermatitis.

Postinflammatory hyperpigmentation (PIH) is a benign but cosmetically disturbing skin lesion, which is notoriously difficult to treat. Standard treatments include topical application of bleaching creams and gels. In this case report, we show that fractional photothermolysis might be a new successful option in the treatment of PIH. Its efficacy must be confirmed by further studies and balanced against possible side effects, but the initial results are promising.

The biogeochemistry of selenium in Sunan grassland, Gansu, Northwest China, casts doubt on the belief that Marco Polo reported selenosis for the first time in history.

In order to clarify the historic academic problem of whether or not livestock poisoning in ancient Suzhou of Northwest China, recorded by Marco Polo in 1295, was selenosis, this study deals with the biogeochemistry of selenium in Sunan County in the Hexi Corridor, which is part of ancient Suzhou in China. It was found that quite a number of farm animals had suffered from intoxication and died as a result of grazing poisonous grasses, mostly Oxytropis DC, Stellera chamaejasme, and Achnatheru inebrians. Toxic symptoms of livestock grazing on Oxytropis DC are similar to those of selenium toxicity, for instance, hair loss and hoof lesions as described by Marco Polo. Therefore, we thought that toxic grass, probably Oxytropis DC, led to the intoxication of livestock recorded by Marco Polo. Average Se concentrations in two members of this species were 0.112 +/- 0.038 mg/kg for the root of Oxytropis glabra, 0.102 +/- 0.027 mg/kg for the stem and leaf of Oxytropis glabra, and 0.066 +/- 0.009 mg/kg for Oxytropis ochrocephala. The average soil selenium concentration was 0.205 +/- 0.127 mg/kg on grassland producing Oxytropis glabra and 0.152 +/- 0.024 mg/kg on grassland producing Oxytropis ochrocephala. The average Se concentration in other plants was 0.076 mg/kg in the root of Ephedra monosperma Mey, 0.029 mg/kg in the root of Rheum palmatum, 0.031 mg/kg in the root of Stellera chamaejasme, 0.037 mg/kg in Achnatherum inebrians, and 0.067 mg/kg in forage grass (Achnatherum splendens ohwi). Selenium concentrations in soils and plants in Sunan County are far less than the thresholds causing selenium toxicity in livestock. As a result, this study concludes that the livestock poisoning recorded by Marco Polo in 1295 might not have been selenosis.

Nitrate-nitrite toxicity in cattle and sheep grazing Dactyloctenium radulans (button grass) in stockyards.

Hungry cattle and sheep introduced to stockyards containing a dominant or pure growth of Dactyloctenium radulans (button grass) suffered acute nitrate-nitrite toxicity in four incidents in inland Queensland between 1993 and 2001. Deaths ranged from 16 to 44%. Methaemoglobinaemia was noted at necropsies in all incidents. An aqueous humour sample from one dead steer contained 75 mg nitrate/L and from one dead sheep contained 100 mg nitrate and 50 mg nitrite/L (normal = ca 5 mg nitrate/L). Both lush and dry button grass were toxic. The nitrate content of button grass from within the stockyards ranged from 4.0 to 12.9% as potassium nitrate equivalent in dry matter and from outside the stockyards ranged from <0.2 to 0.4%. These data suggest that urine and faeces in stockyard soil may boost the nitrate content of button grass to a concentration hazardous to hungry ruminants.

Two cases of equine grass sickness with evidence for soil-borne origin involving botulinum neurotoxin.

Botulism is caused by different types of Clostridium botulinum, a soil bacterium. Equine grass sickness (equine dysautonomia) is suspected of being a clinical form of this disease. On a stud where this disease occurred twice within 8 months, grass and soil samples and necropsy specimens of one horse were tested for the presence of bacterial forms and toxin of C. botulinum. Different types and type mixtures (A-E) of C. botulinum and botulinum neurotoxin were found. For the first time, it has been shown that green grass blades contain botulinum toxin. The results support the hypothesis that equine grass sickness is a clinical form of botulism, a soil-borne disease.

Systemic concentrations of antioxidants and biomarkers of macromolecular oxidative damage in horses with grass sickness.

REASONS FOR PERFORMING STUDY: The aetiopathogenesis of equine grass sickness (EGS) is unknown. The role of free radical-mediated neuronal damage has not previously been investigated in this condition. OBJECTIVES: To investigate the potential contribution of oxidative damage and antioxidant status to neurodegeneration in EGS. METHODS: Systemic levels of surrogate biomarkers were determined in 10 horses with acute EGS and in 2 control populations; 10 healthy horses co-grazing with the 10 EGS horses at the onset of clinical disease, and 10 healthy mares grazing where EGS has not been reported. RESULTS: EGS horses had alterations in levels of several antioxidants, consistent with oxidative stress, the acute phase response and/or the secondary metabolic complications of EGS. EGS horses had elevated plasma dihydroxyphenylalanine (DOPA) levels. CONCLUSIONS: The elevated DOPA levels probably reflected a generalised disturbance of catecholamine metabolism rather than increased DOPA production via free radical-mediated oxidation of tyrosine. However, there was no evidence of systemic macromolecular oxidative damage. POTENTIAL CLINICAL RELEVANCE: Further work is required to determine whether macromolecular oxidative damage occurring at the neuronal level contributes to EGS.

Dicoumarol toxicity in neonatal calves associated with the feeding of sweet vernal (Anthoxanthum odoratum) hay.

Neonatal calves from a seasonal dairy herd in North Western Tasmania were presented for veterinary care due to mortalities and bleeding from multiple orifices. Necropsy examination revealed free blood throughout the parenchymatous organs, body cavities and connective tissues. There was no history of anticoagulant exposure, however, high quantities of dicoumarol were found in samples from hay fed to recently calved cows. No Australian cases of dicoumarol toxicity in neonatal calves have been previously documented, and dicoumarol toxicity in adult cattle would appear to be less common than in colder farming regions of the Northern Hemisphere.

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum).

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. Activated partial thromboplastin time Haemoglobin Packed cell volume Prothrombin time Red cell count

Systemic antibodies to Clostridium botulinum type C: do they protect horses from grass sickness (dysautonomia)?

The aetiology of equine grass sickness (EGS) is still unknown. There is increasing evidence that toxicoinfection with Clostridium botulinum type C is involved. Epidemiological evidence shows that resistance to EGS can occur in older horses and those that have been on a particular pasture for longer or have been in prior contact with the disease. This resistance may be in the form of an immune response to the aetiological agent. Levels of systemic antibodies to the surface antigens of C. botulinum type C (using the closely related and safe C. novyi type A as a phenotypic marker) and to the botulinum type C neurotoxin (BoNT/C) were investigated in horses with and without EGS. Horses with grass sickness were found to have significantly lower levels of systemic IgG to both surface antigens and BoNT/C. Horses with low levels of systemic immunity to these antigens may be more susceptible to developing EGS. There were no significant differences in antibody levels between the different categories of EGS, suggesting systemic immunity to C. botulinum type C does not play a significant role in influencing the severity of the disease. However, horses that had been in contact with EGS or that were grazing land where it had occurred frequently in the past had significantly higher antibody levels to these antigens. These horses may have been exposed to subclinical doses of C. botulinum type C and BoNT/C, resulting in the production of a protective immune response against the putative aetiological agent. This finding is of potential significance for the prospect of prevention of EGS by vaccination against C. botulinum type C.

A simple thin-layer chromatographic method for the detection of ergovaline in leaf sheaths of tall fescue (Festuca arundinacea) infected with Neotyphodium coenophialum.

A relatively simple and inexpensive thin-layer chromatographic (TLC) method is described for the detection and semiquantitative measurement of ergovaline in leaf sheaths of tall fescue (Festuca arundinacea). Samples were finely ground and extracted with methanol. The extracts were filtered and the methanol was evaporated. The aqueous residue was extracted with hexane, followed by chloroform at pH 9. The chloroform extract was concentrated and further purified on a preparative silica gel TLC plate, developed with toluene/ethyl acetate/acetonitrile (50:10:40). The ergovaline band was scraped and eluted with methanol. The eluant was concentrated and an aliquot was applied to a silica gel TLC plate. The plate was developed successively with chloroform/acetone/acetic acid (90:10:5) and chloroform/ethanol (9:1). Ergovaline was visualized with p-dimethylaminobenzaldehyde and sulfuric acid. Semiquantitation of ergovaline was achieved by comparison with a known standard of ergotamine, which was shown to have the same Rf as ergovaline in this system. Spike recovery of ergotamine averaged 60%, with a limit of detection of 200 microg/kg of dry tall fescue leaf sheaths. The method was applied to 15 tall fescue samples with varying degrees of fungal infection, and ergovaline was identified in all contaminated samples with endophyte infection above 15%. Thin-layer chromatography may be also applicable for tall fescue seed, where the ergovaline content is usually higher and the amount of interfering pigments is much lower.

A reduction in interstitial cells of Cajal in horses with equine dysautonomia (grass sickness).

Equine dysautonomia (grass sickness) is a common, frequently fatal disease of horses characterised by dysfunction of the gastrointestinal tract. Interstitial cells of Cajal are the c-Kit-immunoreactive cells responsible for the generation of pacemaker activity in gastrointestinal smooth muscle. Impairment of this pacemaker action has been implicated in several motility disorders in humans and laboratory mammals. The aim of this study was to test the hypothesis that changes in interstitial cells of Cajal may be involved in the pathophysiology of the intestinal dysfunction observed in equine grass sickness. Interstitial cells of Cajal were identified using immunohistochemical labelling with an anti-c-Kit antibody and their density was assessed using a semi-quantitative grading system. Segments of ileum were examined from 24 horses free from gastrointestinal disease and compared to tissues from 28 horses with grass sickness. Segments of the pelvic flexure region of the large colon were examined from 13 horses free from gastrointestinal disease and compared to tissues from 10 horses with grass sickness. In horses with grass sickness, interstitial cells of Cajal were significantly decreased in both the myenteric plexus and circular muscle regions of both ileum and pelvic flexure compared to normal animals. Therefore, it is possible that the decline in interstitial cells of Cajal may be an important factor in the development of intestinal dysmotility observed in grass sickness.

Epidemiology of equine grass sickness: a literature review (1909-1999).

The geographical spread of grass sickness between 1909 and 1999, particularly in England and Wales, is described, and the experimental investigations to identify a causal agent are summarised. The epidemiological techniques used to investigate grass sickness vary from clinical observations, to more advanced methods such as case-control studies using logistic regression analyses. Several risk factors for grass sickness have been reported consistently (age, time of year and recent movement to new pasture or premises) and several others have been reported for which the findings remain inconsistent (weather, pasture type, breed, supplementary feeding and use of anthelmintics).

Central neuropathology of equine grass sickness.

Equine grass sickness (EGS) is an acquired disease of unknown aetiology affecting horses kept at grass. The disease is characterised by postganglionic sympathetic and parasympathetic neuronal pathology and is categorised as a dysautonomia. This study undertook a systematic examination of brain stem cranial nerve nuclei in 59 cases of EGS. Pathology consisting of neuronal chromatolysis was most consistently noted in the lower motor neurons of the general visceral efferent nucleus of CN III and X and the general somatic efferent nuclei of CN III, V, VII and XII. The prevalence of chromatolysis differed significantly between the diagnostic categories and was inversely related to the age of the animal. Duration of disease had a small but significant negative effect on the proportion of nuclei with chromatolytic neurons in chronic cases. The distribution of chromatolytic neurons is unlike that reported in any other equine or human disease; however, it appears to be equivalent to that in other animals with primary dysautonomias. EGS should be classified as a multisystem disease.