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Utilização de imunohistoquímica e AgELISA para detecção de portadores do vírus da diarreia bovina viral em bovinos de engorda
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Autores
Resumo(s)
A Diarreia Bovina Viral é uma das doenças infecciosas dos bovinos de engorda com
maior impacto económico, afectando negativamente todas as fases de produção. Os
animais imunotolerantes, persistentemente infectados (PI) pelo BVDV constituem o
seu principal reservatório, e a sua detecção e eliminação é importante no controlo da
transmissão do vírus na manada. O objectivo deste estudo consistiu em utilizar
imunohistoquímica e AgELISA em amostras de biópsia de pele de bovinos de
engorda, para detectar infecções persistentes. Adicionalmente, procedeu-se à revisão
do conhecimento actual sobre a Diarreia Bovina Viral.
Foram testados 100 vitelos, entre as duas e as 84 semanas de idade. As amostras de
pele, fixadas em formol, foram marcadas para antigénios do BVDV por
imunohistoquímica, e os resultados comparados com os obtidos por AgELISA, em
amostras frescas de pele. Os resultados obtidos foram incompatíveis com infecções
persistentes, para todas as amostras, pelo que nenhum dos animais testados foi
classificado como PI. Contudo, doze animais que foram negativos ao AgELISA
exibiram padrões de marcação imunohistoquímica compatíveis com infecção aguda.
Uma vez que a prevalência elevada de animais persistentemente infectados pode
aumentar o número de infecções agudas, seria importante determinar a prevalência
nacional de infecções persistentes.
ABSTRACT - Using Immunohistochemistry and AgELISA to Detect Animals Persistently Infected with Bovine Viral Diarrhea Virus in Feedlot Cattle - Bovine viral diarrhea is one of the most economically significant infectious diseases of beef cattle, having a negative impact over all stages of production. Immunotolerant, persistently infected (PI) animals are the main reservoir for this virus, and their detection and elimination is important, in order to control its transmission in a herd. The objective of this study was to use immunohistochemical analysis and AgELISA on skin biopsy samples from beef calves, in order to detect persistent infections. Additionally, current knowledge on Bovine Viral Diarrhea was reviewed. One hundred 2 to 84 week-old calves were tested. Formalin-fixed skin biopsy samples were stained for BVDV antigens by immunohistochemistry, and the results were compared to those obtained by AgELISA, performed on fresh skin samples. The results obtained were incompatible with persistent infection, for all samples, so none of the calves tested was classified as a PI animal. However, twelve animals that tested negative with AgELISA exhibited immunohistochemical staining patterns compatible with acute infection. Since a high prevalence of persistently infected animals can increase the number of acute infections, it would be important to determine the national prevalence of persistent infection.
ABSTRACT - Using Immunohistochemistry and AgELISA to Detect Animals Persistently Infected with Bovine Viral Diarrhea Virus in Feedlot Cattle - Bovine viral diarrhea is one of the most economically significant infectious diseases of beef cattle, having a negative impact over all stages of production. Immunotolerant, persistently infected (PI) animals are the main reservoir for this virus, and their detection and elimination is important, in order to control its transmission in a herd. The objective of this study was to use immunohistochemical analysis and AgELISA on skin biopsy samples from beef calves, in order to detect persistent infections. Additionally, current knowledge on Bovine Viral Diarrhea was reviewed. One hundred 2 to 84 week-old calves were tested. Formalin-fixed skin biopsy samples were stained for BVDV antigens by immunohistochemistry, and the results were compared to those obtained by AgELISA, performed on fresh skin samples. The results obtained were incompatible with persistent infection, for all samples, so none of the calves tested was classified as a PI animal. However, twelve animals that tested negative with AgELISA exhibited immunohistochemical staining patterns compatible with acute infection. Since a high prevalence of persistently infected animals can increase the number of acute infections, it would be important to determine the national prevalence of persistent infection.
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
Diarreia Bovina Viral Imunohistoquímica AgELISA Infecção persistente Bovine Viral Diarrhea Imunohistochemistry Persistent infection
Contexto Educativo
Citação
Noiva, R.M.G. (2010). Utilização de imunohistoquímica e AgELISA para detecção de portadores do vírus da diarreia bovina viral em bovinos de engorda. Dissertação de Mestrado. Universidade Técnica de Lisboa, Faculdade de Medicina Veterinária, Lisboa.
Editora
Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária