Clinic for Zoo Animals, Exotic Pets and Wildlife, University of Zurich, Zurich, Switzerland.
Vet Microbiol. 2011 Mar 24;148(2-4):207-12. doi: 10.1016/j.vetmic.2010.09.018. Epub 2010 Sep 29.
In late summer 2006 considerable mortality in wild and captive Passeriformes and Strigiformes was observed in Zurich, Switzerland. All animals were found in a range of 2 km(2). Observed clinical signs involved depression, ruffled plumage, incoordination, seizures and peracute death. Nutritional status was generally moderate to poor in wild birds, and variable in captive animals. Necropsy showed marked splenomegaly, a mild hepatomegaly, and pulmonary hyperemia in most animals. Histopathologic lesions were very discrete and consisted mainly of neuronal necrosis, leucocytolysis in and around the brain blood vessels, and miliary liver necrosis. The diagnosis Usutu virus (USUV) infection was established by USUV-specific immunohistochemistry and reverse transcription-polymerase chain reaction. Partial nucleotide sequence comparisons revealed>99% identity between the viruses that emerged in Zurich in 2006, in Vienna in 2001, and in Budapest in 2005. Since 2008 a significantly lower mortality was observed in wild Passeriformes, but USUV infection was confirmed for the first time beyond Zurich city limits. Indoor housing and regular treatment against ectoparasites are likely to have prevented acute USUV disease in captive Strigiformes. USUV is a mosquito-borne flavivirus causing fatalities in various avian species. After the initial European outbreaks in Austria in 2001 it appears that the virus has extended its range in Central Europe and has established a transmission cycle between local bird and mosquito species. Further episodes of increased avian mortality in the forthcoming years, with impact on wild and captive bird populations, predominantly Passeriformes and Strigiformes, can be anticipated. Furthermore, the possibility of broader dispersal of USUV in Europe during the next mosquito seasons must be considered and an increased mortality in Passeriformes and Strigiformes must be expected until protective "flock immunity" is established. Collections of valuable and endangered Passeriformes and Strigiformes, especially young of the year, should therefore be housed indoors or treated against ectoparasites at acceptable intervals between July and September each year.
2006 年夏末，瑞士苏黎世的野生和圈养雀形目和鸮形目鸟类大量死亡。所有动物都在 2 公里范围内被发现。观察到的临床症状包括抑郁、羽毛蓬乱、不协调、癫痫发作和急性死亡。野生鸟类的营养状况一般为中等至较差，而圈养动物的营养状况则不同。剖检显示大多数动物的脾脏肿大明显，肝脏肿大轻微，肺部充血。组织病理学病变非常离散，主要包括神经元坏死、脑血管周围的白细胞溶解和粟粒状肝坏死。通过针对乌图病毒（USUV）的特异性免疫组织化学和逆转录-聚合酶链反应确定了 USUV 感染的诊断。部分核苷酸序列比较显示，2006 年在苏黎世、2001 年在维也纳和 2005 年在布达佩斯出现的病毒之间的同一性超过 99%。自 2008 年以来，野生雀形目鸟类的死亡率明显降低，但首次在苏黎世市界之外证实了 USUV 感染。室内饲养和定期防治外寄生虫可能防止了圈养鸮形目鸟类的急性 USUV 疾病。USUV 是一种蚊媒黄病毒，可导致各种鸟类死亡。2001 年奥地利首次爆发后，该病毒似乎已在中欧地区扩大了范围，并在当地鸟类和蚊子之间建立了传播循环。未来几年，预计候鸟死亡率会增加，这将对野生和圈养鸟类种群（主要是雀形目和鸮形目）产生影响。此外，在接下来的蚊子季节，USUV 在欧洲的传播范围可能会扩大，必须考虑到这一点，并且预计在建立保护性“群体免疫”之前，雀形目和鸮形目鸟类的死亡率会增加。因此，应将收集的有价值和濒危的雀形目和鸮形目鸟类，特别是幼鸟，放在室内饲养，或每年 7 月至 9 月期间以可接受的间隔时间进行除虫。
