Isolamento, avaliação do comportamento de amostras de vírus ectima contagioso e melhoramento de técnicas de diagnóstico e de cultivo in vitro

• Autor(a) principal: SANTANA, Rosana Léo de
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5838
• topic: Ectima contagioso; Parapoxvírus; Caprino; Doença; Contagious ecthyma; Orf; CIENCIAS AGRARIAS::MEDICINA VETERINARIA

Contagious ecthyma is a severe and proliferative viral disease affecting ovine and caprine species, and eventually men, caused by the contagious ecthyma virus (ECV) of the Parapoxvirus genus. The disease is spread worldwide, including in Brazil, where in the state of Pernambuco, due to its endemicity, can be mistaken by other vesicular diseases such as the Foot and mouth Disease, which requires its diagnostic differentiation. Meanwhile, the control of the infection in endemic regions is limited due to the difficulties in replicating the virus in cell cultures, for the development of vaccines. The purpose of this work is to evaluate the behavior of ECV samples in primary cultures of fetal caprine cornea cells, and also to establish an efficient molecular diagnostic method for field samples, and to analyze the phylogenetic profile of the virus samples studied. Crust samples from twenty-two sheep and seven goats from the states of Pernambuco, Bahia, Sergipe and Paraiba presenting the clinical symptoms of EC were inoculated in cell monolayers, during seven consecutive passages at weekly intervals. During all passages, starting at 24 hours post-infection was observed a cytopathic effect (CE) characterized by cell rounding, cell fusion with the formation of small syncytia, cytoplasmic inclusion and vacuolization. The intensity of cell detachment from the layers ranged from 25% to 100% which varied according to the viral sample. We concluded that the primary cultures of the fetal caprine cornea cell appeared highly permissible to replication of ECV and the isolated samples of ECV seemed to adapt to the utilized culture with a slight variation among samples, and the identification by PCR showed to be an applicable method to the differential diagnosis of vesicular diseases, especially to support the actions of PNEFA, where goats and sheep are considered sentinel animals. The phylogenetic analysis showed that ORFV sequences from the northeastern of Brazil are highly correlated showing identical sequences up to 99%. In addition, they present more than 80% sequence identity with other isolates of ORFV worldwide.