Wünschmann Arno, Shivers Jan, Bender Jeff, Carroll Larry, Fuller Susan, Saggese Miguel, van Wettere Arnaud, Redig Pat
Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, 1333 Gortner Avenue, St. Paul, MN 55108, USA.
Avian Dis. 2005 Jun;49(2):252-9. doi: 10.1637/7297-103104R.
The carcasses of 25 great horned owls and 12 goshawks were investigated for West Nile virus (WNV) infection by immunohistochemistry (IHC) performed on various organs, including brain, spinal cord, heart, kidney, eye, bone marrow, spleen, liver, lungs, pancreas, intestine, and proventriculus, using a WNV-antigen-specific monoclonal antibody and by WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR), performed on fresh brain tissue only. WNV infection was diagnosed by IHC in all owls and all goshawks. WNV-specific RT-PCR amplified WNV-RNA in the brain of all goshawks but only 12 owls (48%). Cachexia was a common macroscopic finding associated with WNV infection in owls (76%). Myocarditis was occasionally macroscopically evident in goshawks (33%). Microscopically, inflammatory lesions, including lymphoplasmacytic and histiocytic encephalitis, myocarditis, endophthalmitis, and pancreatitis were present in both species but were more common and more severe in goshawks than in owls. The most characteristic brain lesion in owls was the formation of glial nodules, in particular in the molecular layer of the cerebellum, while encephalitis affecting the periventricular parenchyma of the cerebral cortex was common in the goshawks. In owls, WNV-antigen-positive cells were present usually only in very small numbers per organ. Kidney (80%), heart (39%), and cerebellum (37%) were the organs that most commonly contained WNV antigen in owls. WNV antigen was frequently widely distributed in the organs of infected goshawks, with increased amounts of WNV antigen in the heart and the cerebrum. Spleen (75%), cerebellum (66%), heart (58%), cerebrum (58%), and eye (50%) were often WNV-antigen positive in goshawks. In contrast with the goshawks, WNV antigen was not present in cerebral and retinal neurons of owls. WNV infection appears to be capable of causing fatal disease in great horned owls and goshawks. However, the distribution and severity of histologic lesions, the antigen distribution in the various organs, and the amount of antigen varied among both species. Therefore, the diagnostician may choose organs for histology and immunohistochemistry as well as RT-PCR depending on the investigated species in order to avoid false-negative results.
对25只大角鸮和12只苍鹰的尸体进行了西尼罗河病毒（WNV）感染调查。通过免疫组织化学（IHC）对包括脑、脊髓、心脏、肾脏、眼睛、骨髓、脾脏、肝脏、肺、胰腺、肠道和前胃在内的各种器官进行检测，使用WNV抗原特异性单克隆抗体；同时通过仅对新鲜脑组织进行的WNV特异性逆转录聚合酶链反应（RT-PCR）进行检测。通过免疫组织化学在所有的鸮和所有的苍鹰中均诊断出WNV感染。WNV特异性RT-PCR在所有苍鹰的脑中扩增出了WNV-RNA，但在鸮中仅12只（48%）检测到。恶病质是与鸮的WNV感染相关的常见大体表现（76%）。苍鹰偶尔可见大体明显的心肌炎（33%）。显微镜下，两个物种均存在炎症性病变，包括淋巴细胞性和组织细胞性脑炎、心肌炎、眼内炎和胰腺炎，但苍鹰比鸮更常见且更严重。鸮中最具特征性的脑病变是胶质结节的形成，特别是在小脑分子层，而影响大脑皮质脑室周围实质的脑炎在苍鹰中很常见。在鸮中，每个器官中WNV抗原阳性细胞通常数量很少。肾脏（80%）、心脏（39%）和小脑（37%）是鸮中最常含有WNV抗原的器官。WNV抗原在感染的苍鹰器官中常广泛分布，心脏和大脑中WNV抗原量增加。脾脏（75%）、小脑（66%）、心脏（58%）、大脑（58%）和眼睛（50%）在苍鹰中常为WNV抗原阳性。与苍鹰不同，WNV抗原在鸮的脑和视网膜神经元中不存在。WNV感染似乎能够在大角鸮和苍鹰中引起致命疾病。然而，组织学病变的分布和严重程度、抗原在各个器官中的分布以及抗原量在两个物种之间存在差异。因此，诊断人员可根据所调查的物种选择用于组织学、免疫组织化学以及RT-PCR检测的器官，以避免假阴性结果。
