Bingham J, Lunt R A, Green D J, Davies K R, Stevens V, Wong F Y K
CSIRO-Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia.
Aust Vet J. 2010 Jun;88(6):204-10. doi: 10.1111/j.1751-0813.2010.00582.x.
To study the potential role of an Australian corvid, the little raven (Corvus mellori), in the surveillance for exotic West Nile virus (WNV) in Australia.
In a series of trials, little ravens were infected with WNV (strain 4132 New York 1999) and Kunjin virus (strain K42886) by the intramuscular route. They were observed for 20 days during which blood and swab samples were taken for virus isolation. Tissue samples were taken from ravens humanely killed during the acute infection period, and at the termination of the trials, for virus isolation, histopathology and immunohistochemistry.
Ravens infected with WNV became mildly ill, but all recovered and seroconverted. Blood virus titres peaked around 3 to 4 days after inoculation at levels between 10(3.0) to 10(7.5) plaque forming units/mL. Virus or viral antigen was detected in spleen, liver, lung, kidney, intestine, testis and ovary by virus isolation and/or immunohistochemistry. WNV was detected in oral and cloacal swabs from 2 to 7 days post inoculation. The molecular and pathogenic characteristics of the inocula were consistent with them being of high virulence, as expected for this isolate. Ravens infected with Kunjin virus developed viraemia and seroconverted, although they did not develop disease.
Little ravens do not develop severe disease in response to virulent WNV infection and for this reason may not be important sentinel hosts in the event of an outbreak of WNV, as in North America. However, as they have relatively high viraemias, they may be able to support virus cycles.
研究澳大利亚一种鸦科鸟类——小嘴乌鸦（Corvus mellori）在澳大利亚外来西尼罗河病毒（WNV）监测中的潜在作用。
在一系列试验中，通过肌肉注射途径将WNV（1999年纽约4132株）和库京病毒（K42886株）感染小嘴乌鸦。对它们进行20天的观察，在此期间采集血液和拭子样本用于病毒分离。在急性感染期以及试验结束时，对人道处死的乌鸦采集组织样本，用于病毒分离、组织病理学和免疫组织化学检查。
感染WNV的乌鸦出现轻度疾病，但全部康复并产生血清转化。接种后约3至4天血液病毒滴度达到峰值，水平在10(3.0)至10(7.5) 蚀斑形成单位/毫升之间。通过病毒分离和/或免疫组织化学在脾脏、肝脏、肺、肾、肠、睾丸和卵巢中检测到病毒或病毒抗原。接种后2至7天在口腔和泄殖腔拭子中检测到WNV。接种物的分子和致病特征与预期的高毒力一致，符合该分离株的特性。感染库京病毒的乌鸦出现病毒血症并产生血清转化，尽管它们未发病。
小嘴乌鸦在感染强毒力WNV后不会出现严重疾病，因此在WNV暴发时，它们可能不像在北美那样是重要的哨兵宿主。然而，由于它们具有相对较高的病毒血症，它们可能能够支持病毒循环。
