RESUMO
Partly due to climate change, and partly due to changes of human habitat occupation, the impact of tick-borne viruses is increasing. Nairobi sheep disease virus (NSDV) and Ganjam virus (GV) are two names for the same virus, which causes disease in sheep and goats and is currently known to be circulating in India and East Africa. The virus is transmitted by ixodid ticks and causes a severe hemorrhagic disease. We have developed a real-time PCR assay for the virus genome and validated it in a pilot study of the pathogenicity induced by two different isolates of NSDV/GV. One isolate was highly adapted to tissue culture, grew in most cell lines tested, and was essentially apathogenic in sheep. The second isolate appeared to be poorly adapted to cell culture and retained pathogenicity in sheep. The real-time PCR assay for virus easily detected 4 copies or less of the viral genome, and allowed a quantitative measure of the virus in whole blood. Measurement of the changes in cytokine mRNAs showed similar changes to those observed in humans infected by the closely related virus Crimean Congo hemorrhagic fever virus.
Assuntos
Citocinas/genética , Doenças das Cabras/genética , Doença dos Ovinos de Nairobi/genética , Vírus da Doença do Carneiro de Nairobi/patogenicidade , Reação em Cadeia da Polimerase em Tempo Real/métodos , Animais , Citocinas/metabolismo , Doenças das Cabras/imunologia , Doenças das Cabras/virologia , Cabras , Doença dos Ovinos de Nairobi/imunologia , Doença dos Ovinos de Nairobi/virologia , Vírus da Doença do Carneiro de Nairobi/classificação , Vírus da Doença do Carneiro de Nairobi/genética , Vírus da Doença do Carneiro de Nairobi/isolamento & purificação , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Ovinos , Virulência , Replicação ViralRESUMO
To determine whether transplacental transmission could explain overwintering of bluetongue virus in the United Kingdom, we studied calves born to dams naturally infected during pregnancy in 2007-08. Approximately 33% were infected transplacentally; some had compromised health. In all infected calves, viral load decreased after birth; no evidence of persistent infection was found.