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The atypical porcine pestivirus (APPV) belongs to the species Pestivirus K of the genus Pestivirus and the family Flaviviridae, and it has been associated with congenital tremor (CT) type A-II in newborn piglets. Although APPV was discovered in 2015, evidence shows that APPV has circulated in pig herds for many years, at least since 1986. Due to the frequently reported outbreaks of CT on different continents, the importance of this virus for global pig production is notable. Since 2015, several studies have been conducted to clarify the association between APPV and CT. However, some findings regarding APPV infection and the measures taken to control and prevent the spread of this virus need to be contextualized to understand the infection better. This review attempts to highlight advances in the understanding of APPV associated with type A-II CT, such as etiology, epidemiology, diagnosis, and control and prevention measures, and also describes the pathophysiology of the infection and its consequences for pig production. Further research still needs to be conducted to elucidate the host's immune response to APPV infection, the control and prevention of this infection, and the possible development of vaccines.

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The present study describes the spontaneous and experimental poisoning of goats by Festuca argentina in Argentine Patagonia. In April 2017, eight seven-month-old Creole male goats were accidentally introduced into a paddock that contained F. argentina. After four days, two of the goats were found dead and four out of the six remaining goats were clinically affected. Two of the latter had to be later euthanized in extremis. The main clinical signs were progressive nervous signs, starting with moderate muscle tremors, wide-based stance and ataxia. Postmortem examination was performed on the two euthanized goats. Epidermal fragments of F. argentina were found in the rumen samples from the necropsied goats and the fecal samples from the four affected goats. For the experimental poisoning, fresh sheaths of F. argentina collected from the paddock were offered to two goats at 10 g/kg body weight for 3 days. After 24-36 h, both animals exhibited severe muscle tremors, reluctance to move, tetanic convulsions, and opisthotonus. In both the spontaneously and experimentally poisoned goats, gross lesions were similar and consisted of dehydration, petechial hemorrhages in the epicardium and congestion. The main microscopic findings consisted of degeneration and loss of Purkinje cells and torpedoes in the granular layer of the cerebellum. The F. argentina sheaths collected from the pasture were found to contain tremorgenic indole-diterpene alkaloids. Taken together, the results of the present study suggest that the tremorgenic syndrome observed in the spontaneously poisoned goats was due to poisoning by F. argentina.

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Poisonous plants are a significant cause of death among adult cattle in Brazil. Plants that affect the central nervous system are widely spread throughout the Brazilian territory and comprise over 30 toxic species, including the genus Ipomoea, commonly associated with a lysosomal storage disease and a tremorgenic syndrome in livestock. We describe natural and experimental Ipomoea pes caprae poisoning in cattle from a herd in the Northside of Rio de Janeiro, Brazil. Affected cattle presented episodes of severe ataxia, abnormal posture followed by falling, muscular tremor, contraction, and spasticity, more prominent in the limbs, intensified by movement and forthcoming, and recumbence. Grossly, a substantial amount of leaves and petioles were found in the rumen. Histopathological examination showed degenerative neuronal changes, mostly in cerebellar Purkinje cells, which were confirmed with Bielschowsky silver. The characteristic clinical changes and mild histological lesion strongly suggested a tremorgenic syndrome. Lectin- immunohistochemistry evaluation reinforced this hypothesis; all lectins tested failed to react with affect neurons and Purkinje cells, which ruled out an underlying lysosomal storage disease. One calf given I. pes caprae leaves experimentally developed clinical signs similar to natural cases. On the 28th day of the experiment, the plant administration was suspended, and the calf recovered within four days. I. pes caprae's spontaneous tremorgenic syndrome in cattle is conditioned to exclusive feeding for several months. We were able to experimentally reproduce toxic clinical signs 12 days following the ingestion.(AU)

A intoxicação por plantas tóxicas está entre as três causas de morte mais importantes em bovinos adultos no Brasil. O grupo das plantas que causam alterações neurológicas, muito bem representada no país, encerra mais de trinta espécies tóxicas, entre as quais do gênero Ipomoea, amplamente distribuídas no território brasileiro. As plantas tóxicas desse gênero podem causar doenças do armazenamento ou síndrome tremorgênica. Descrevem-se a intoxicação natural e reprodução experimental por Ipomoea pes caprae em bovinos, verificada no norte do Estado do Rio de Janeiro. Foram observados episódios de intensa ataxia locomotora, postura anormal seguida de queda, incapacidade de levantar-se, tremores, contrações, espasticidades musculares nos membros, intensificados após estimulação ou a simples aproximação e decúbito. Nos bovinos afetados há mais de 6 meses, os sinais clínicos tornavam-se permanentes. À necropsia havia apenas significativa quantidade de folhas e pecíolos da planta no rúmen. O estudo histopatológico evidenciou lesões neuronais degenerativas principalmente nos neurônios de Purkinje. A impregnação argêntica pela técnica de Bielschowsky ratificou esses achados microscópicos. As lesões histológicas sutis associadas ao quadro clínico indicam que trata-se de intoxicação tremorgênica. O fato de não haver nenhum armazenamento intracitoplasmático, confirmado pelo resultado do estudo lectino-histoquímico (não houve afinidade das lectinas Con-A, WGA e sWGA e de outras lectinas empregadas aos neurônios de Purkinje e outros neurônios afetados), é suficiente para descartar a possibilidade de tratar-se de doença do armazenamento. No bezerro intoxicado experimentalmente verificaram-se sinais clínicos semelhantes, entretanto, com a interrupção do fornecimento da planta no 28º dia, os sinais clínicos desapareceram após quatro dias. I. pes caprae causa síndrome tremorgênica espontânea em bovinos, quando ingerida como alimentação exclusiva durante períodos prolongados (muitos meses). Experimentalmente, os primeiros sinais clínicos da intoxicação foram reproduzidos após 12 dias de ingestão da planta.(AU)

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RESUMO

Poisonous plants are a significant cause of death among adult cattle in Brazil. Plants that affect the central nervous system are widely spread throughout the Brazilian territory and comprise over 30 toxic species, including the genus Ipomoea, commonly associated with a lysosomal storage disease and a tremorgenic syndrome in livestock. We describe natural and experimental Ipomoea pes caprae poisoning in cattle from a herd in the Northside of Rio de Janeiro, Brazil. Affected cattle presented episodes of severe ataxia, abnormal posture followed by falling, muscular tremor, contraction, and spasticity, more prominent in the limbs, intensified by movement and forthcoming, and recumbence. Grossly, a substantial amount of leaves and petioles were found in the rumen. Histopathological examination showed degenerative neuronal changes, mostly in cerebellar Purkinje cells, which were confirmed with Bielschowsky silver. The characteristic clinical changes and mild histological lesion strongly suggested a tremorgenic syndrome. Lectin- immunohistochemistry evaluation reinforced this hypothesis; all lectins tested failed to react with affect neurons and Purkinje cells, which ruled out an underlying lysosomal storage disease. One calf given I. pes caprae leaves experimentally developed clinical signs similar to natural cases. On the 28th day of the experiment, the plant administration was suspended, and the calf recovered within four days. I. pes caprae's spontaneous tremorgenic syndrome in cattle is conditioned to exclusive feeding for several months. We were able to experimentally reproduce toxic clinical signs 12 days following the ingestion.(AU)

A intoxicação por plantas tóxicas está entre as três causas de morte mais importantes em bovinos adultos no Brasil. O grupo das plantas que causam alterações neurológicas, muito bem representada no país, encerra mais de trinta espécies tóxicas, entre as quais do gênero Ipomoea, amplamente distribuídas no território brasileiro. As plantas tóxicas desse gênero podem causar doenças do armazenamento ou síndrome tremorgênica. Descrevem-se a intoxicação natural e reprodução experimental por Ipomoea pes caprae em bovinos, verificada no norte do Estado do Rio de Janeiro. Foram observados episódios de intensa ataxia locomotora, postura anormal seguida de queda, incapacidade de levantar-se, tremores, contrações, espasticidades musculares nos membros, intensificados após estimulação ou a simples aproximação e decúbito. Nos bovinos afetados há mais de 6 meses, os sinais clínicos tornavam-se permanentes. À necropsia havia apenas significativa quantidade de folhas e pecíolos da planta no rúmen. O estudo histopatológico evidenciou lesões neuronais degenerativas principalmente nos neurônios de Purkinje. A impregnação argêntica pela técnica de Bielschowsky ratificou esses achados microscópicos. As lesões histológicas sutis associadas ao quadro clínico indicam que trata-se de intoxicação tremorgênica. O fato de não haver nenhum armazenamento intracitoplasmático, confirmado pelo resultado do estudo lectino-histoquímico (não houve afinidade das lectinas Con-A, WGA e sWGA e de outras lectinas empregadas aos neurônios de Purkinje e outros neurônios afetados), é suficiente para descartar a possibilidade de tratar-se de doença do armazenamento. No bezerro intoxicado experimentalmente verificaram-se sinais clínicos semelhantes, entretanto, com a interrupção do fornecimento da planta no 28º dia, os sinais clínicos desapareceram após quatro dias. I. pes caprae causa síndrome tremorgênica espontânea em bovinos, quando ingerida como alimentação exclusiva durante períodos prolongados (muitos meses). Experimentalmente, os primeiros sinais clínicos da intoxicação foram reproduzidos após 12 dias de ingestão da planta.(AU)

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O tremor de cabeça idiopático, também conhecido como tremor de cabeça episódico, ou head bobbing se trata de distúrbio paroxístico de base hereditária, sendo considerado uma condição benigna que se manifesta com tremores descontrolados da cabeça, de início e término espontâneos. Este relato apresenta um caso de head bobbing em um bulldog francês fêmea de 1 ano e 7 meses. A paciente apresentava histórico de tremor restrito à região de cabeça, principalmente quando estava em repouso, e durante os episódios se mantinha consciente e responsiva a estímulos externos. Os exames clínico geral e neurológico foram realizados e não evidenciaram nenhuma alteração aparente. Hemograma e exames bioquímicos não apresentaram alterações significativas. Foi realizada também a coleta de líquido cefalorraquidiano (LCR), que estava dentro dos parâmetros normais. O diagnóstico clínico foi obtido por meio do histórico, raça, idade, ausência de outros sinais clínicos associados e descartando outras possíveis causas de tremores.

The idiopathic head tremor, also known as episodic head tremor, or head bobbing is an inherited paroxysmal disorder and is considered a benign condition manifested by spontaneous uncontrolled tremors. This report presents a head bobbing in a 1 year and 7 months old female French Bulldog. The patient had a history of tremor restrict to the head region, especially when at rest, during episodes remained conscious and responsive to external stimulation. General clinical and neurological examination were performed and showed no apparent alteration. Blood count and biochemistry evidenced no significant changes. CSF collection was also performed, which was within normal parameters. The clinical diagnosis was obtained by history, race, age, absence of others clinical signs and ruling out other possible causes of tremors.

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RESUMO

O tremor de cabeça idiopático, também conhecido como tremor de cabeça episódico, ou head bobbing se trata de distúrbio paroxístico de base hereditária, sendo considerado uma condição benigna que se manifesta com tremores descontrolados da cabeça, de início e término espontâneos. Este relato apresenta um caso de head bobbing em um bulldog francês fêmea de 1 ano e 7 meses. A paciente apresentava histórico de tremor restrito à região de cabeça, principalmente quando estava em repouso, e durante os episódios se mantinha consciente e responsiva a estímulos externos. Os exames clínico geral e neurológico foram realizados e não evidenciaram nenhuma alteração aparente. Hemograma e exames bioquímicos não apresentaram alterações significativas. Foi realizada também a coleta de líquido cefalorraquidiano (LCR), que estava dentro dos parâmetros normais. O diagnóstico clínico foi obtido por meio do histórico, raça, idade, ausência de outros sinais clínicos associados e descartando outras possíveis causas de tremores.(AU)

The idiopathic head tremor, also known as episodic head tremor, or head bobbing is an inherited paroxysmal disorder and is considered a benign condition manifested by spontaneous uncontrolled tremors. This report presents a head bobbing in a 1 year and 7 months old female French Bulldog. The patient had a history of tremor restrict to the head region, especially when at rest, during episodes remained conscious and responsive to external stimulation. General clinical and neurological examination were performed and showed no apparent alteration. Blood count and biochemistry evidenced no significant changes. CSF collection was also performed, which was within normal parameters. The clinical diagnosis was obtained by history, race, age, absence of others clinical signs and ruling out other possible causes of tremors.(AU)

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The aim of this study was to describe the clinical, pathological and epidemiological aspects of an outbreak of tremorgenic syndrome in suckling lambs associated to Ipomoea asarifolia poisoning occurred in the metropolitan region of Recife, northeastern Brazil. Eight suckling Dorper lambs presented clinical signs after their mothers being kept in pasture invaded by I. asarifolia. Sixty percent of adult sheep, including lactating ewe, only exhibited engorged episcleral vessels. The suckling lambs exhibited neurological signs, such as head and neck tremors, dysmetria, wide-based stance, uncoordinated gait, unusual standing and imbalance followed by falls. These signs became more evident when the animals were forced to move. No gross lesions were found in a necropsied lamb that had died spontaneously. The histological findings were axonal spheroids in the cerebellum granular layer and numerous necrotic neurons in the cerebral cortex and cerebellum molecular layer. This study demonstrates that Ipomoea asarifolia causes tremorgenic syndrome. The toxin is eliminated through milk and suckling lambs exhibit a greater susceptibility compared to adult animals.

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The aim of this study was to describe the clinical, pathological and epidemiological aspects of an outbreak of tremorgenic syndrome in suckling lambs associated to Ipomoea asarifolia poisoning occurred in the metropolitan region of Recife, northeastern Brazil. Eight suckling Dorper lambs presented clinical signs after their mothers being kept in pasture invaded by I. asarifolia. Sixty percent of adult sheep, including lactating ewe, only exhibited engorged episcleral vessels. The suckling lambs exhibited neurological signs, such as head and neck tremors, dysmetria, wide-based stance, uncoordinated gait, unusual standing and imbalance followed by falls. These signs became more evident when the animals were forced to move. No gross lesions were found in a necropsied lamb that had died spontaneously. The histological findings were axonal spheroids in the cerebellum granular layer and numerous necrotic neurons in the cerebral cortex and cerebellum molecular layer. This study demonstrates that Ipomoea asarifolia causes tremorgenic syndrome. The toxin is eliminated through milk and suckling lambs exhibit a greater susceptibility compared to adult animals.(AU)

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The indolizidine alkaloid swainsonine, found in some Astragalus and Oxytropis (i.e., locoweed) species, is a potent cellular glycosidase inhibitor that often poisons livestock. Other toxic genera such as some Ipomoea species also contain swainsonine as well as calystegines which are similar polyhydroxy alkaloids. The toxicity of calystegines is poorly characterized; however, they are also potent glycoside inhibitors capable of intestinal and cellular glycoside dysfunction. The objective of this study was to directly compare A. lentiginosus and I. carnea poisoning in goats to better characterize the role of the calystegines. Three groups of four goats each were treated with ground alfalfa (control), I. carnea or A. lentiginosus to obtain daily doses of 0.0, 1.5, and 1.5 mg swainsonine/kg bw per day, respectively, for 45 days. Animals were observed daily and weekly body weights, serum enzyme activities, and serum swainsonine concentrations were determined. At day 45 all animals were euthanized and necropsied. Goats treated with A. lentiginosus and I. carnea developed clinical disease characterized by mild intention tremors and proprioceptive deficits. Goats treated with A. lentiginosus developed clinical disease sooner and with greater consistency. No differences in body weight, serum swainsonine concentrations and serum enzyme activity were observed between goats treated with A. lentiginosus and I. carnea. Additionally, there were no differences in the microscopic and histochemical studies of the visceral and neurologic lesions observed between goats treated with A. lentiginosus and I. carnea. These findings suggest that I. carnea-induced clinical signs and lesions are due to swainsonine and that calystegines contribute little or nothing to toxicity in goats in the presence of swainsonine.

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