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Publication
A Pitomicotoxicose (eczema facial) em ruminantes
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Advisor(s)
Abstract(s)
A pitomicotoxicose, mais conhecida como eczema facial, é uma doença que afeta os
ruminantes particularmente em regime de pastoreio, estando descrita em várias regiões húmidas e
clima temperado, nomeadamente na Nova Zelândia, Austrália, Açores e País Basco. Esta doença devese à presença da micotoxina esporidesmina, que é produzida pelo fungo Pithomyces chartarum. A
disponibilidade deste fungo é maior no final do verão e no início do outono, quando estão reunidas as
condições favoráveis ao seu crescimento (temperaturas mínimas de 12ºC e humidade relativa de 80 %,
durante pelo menos três dias consecutivos).
A esporidesmina ingerida é absorvida e transportada pelo sistema porta ao fígado, originando
pericolangiohepatite, fibrose hepática e colestase. A colestase leva à acumulação de fitoeritrina, um
fotopigmento, que resulta no quadro de fotossensibilização. Além deste, ocorrem sinais inespecíficos,
como disorexia e diarreia transitória, diminuição da produção leiteira, diminuição dos ganhos de peso
vivo e infertilidade, que contribuem para o grande impacto económico desta doença.
As várias medidas de controlo incluem a identificação dos períodos de risco, com a
implementação de sistema de alerta e contagem dos esporos por grama de erva, a gestão do pastoreio
e a suplementação de zinco. Para uma gestão a longo prazo, a seleção genética para a tolerância dos
animais à esporidesmina apresenta-se como um método promissor.
Pitomycotoxicosis, better known as facial eczema, is a disease that affects ruminants particularly in grazing systems, being described in several humid regions and temperate climate, as New Zealand, Australia, Azores and Basque Country. It is due to the presence of the mycotoxin sporidesmin, which is produced by the fungus Pithomyces chartarum. The availability of this fungus is greater in late summer and early autumn, when favorable conditions to its growth are met (minimum temperatures of 12ºC and relative humidity of 80 %, for at least three consecutive days). Ingested sporidesmin is absorbed and transported through the portal system to the liver, causing pericolangiohepatitis, hepatic fibrosis and cholestasis. Cholestasis leads to the accumulation of phytoerythrin, a photopigment, which results in photosensibility. In addition to this, nonspecific signs occur, such as dysorexia and transient diarrhoea, decreasing milk production, impacting live weight gain and infertility, which contribute to the great economic impact of this disease. The various control measures include the identification of risk periods, the implementation of an alert system and spore counts per gram of grass, grazing management and zinc supplementation. For long-term management, genetic selection for the tolerance of animals to sporidesmin is promising method.
Pitomycotoxicosis, better known as facial eczema, is a disease that affects ruminants particularly in grazing systems, being described in several humid regions and temperate climate, as New Zealand, Australia, Azores and Basque Country. It is due to the presence of the mycotoxin sporidesmin, which is produced by the fungus Pithomyces chartarum. The availability of this fungus is greater in late summer and early autumn, when favorable conditions to its growth are met (minimum temperatures of 12ºC and relative humidity of 80 %, for at least three consecutive days). Ingested sporidesmin is absorbed and transported through the portal system to the liver, causing pericolangiohepatitis, hepatic fibrosis and cholestasis. Cholestasis leads to the accumulation of phytoerythrin, a photopigment, which results in photosensibility. In addition to this, nonspecific signs occur, such as dysorexia and transient diarrhoea, decreasing milk production, impacting live weight gain and infertility, which contribute to the great economic impact of this disease. The various control measures include the identification of risk periods, the implementation of an alert system and spore counts per gram of grass, grazing management and zinc supplementation. For long-term management, genetic selection for the tolerance of animals to sporidesmin is promising method.
Description
Keywords
Eczema facial Esporidesmina Hepatotoxina Pithomyces chartarum Pitomicotoxicose Prevenção Facial eczema Hepatotoxin Pitomycotoxicosis Pithomyces chartarum Prevention Sporidesmin