title: Pathology and immunohistochemical findings of west nile virus infection in psittaciformes.
abstract: West Nile virus (WNV) infection was diagnosed in 38 psittacine birds based on histology, immunohistochemistry, and reverse transcriptase polymerase chain reaction (RT-PCR). Rosellas (Platycercus spp, n = 13), conures (Enicognathus, Aratinga, and Nandayus spp, n = 6), and lorikeets (Trichoglossus spp, n = 6) represented the most commonly affected species. Clinical signs ranged from lethargy, ruffled feathers, anorexia, and weight loss in most birds to sudden death in others. Except for mild to moderate enlargement of liver and spleen, there were no significant gross lesions at necropsy. Histopathologic findings included lymphoplasmacytic and histiocytic hepatitis, interstitial nephritis, myocarditis, splenitis, enteritis, pancreatitis, and occasionally, encephalitis. Viral antigen was detected by immunohistochemistry in 34 of 35 hearts (97.1%), 29 of 32 pancreata (90.6%), 33 of 37 kidneys (89.2%), 31 of 35 intestines (88.6%), 27 of 33 gizzards (81.8%), 8 of 10 ovaries (80%), 27 of 34 spleens (79.4%), 30 of 38 livers (78.9%), 23 of 32 lungs (71.9%), 21 of 31 proventriculi (67.7%), 14 of 21 adrenals (66.7%), 10 of 16 testes (62.5%), 17 of 30 brains (56.7%), 15 of 27 skins (55.5%), 3 of 6 oviducts (50%), 15 of 34 skeletal muscles (44.1%), 11 of 27 crop or esophagus (40.7%), and 1 of 6 thymuses (16.7%). Kidney was positive for WNV by RT-PCR in all the cases tested. In conclusion, Psittaciformes are susceptible to West Nile virus infection, and WNV infections are often associated with nonspecific clinical signs and widespread viral distribution in this order of birds.
authors.affiliation: Veterinary Pathology Division, Faculty of Veterinary Medicine, Teramo University, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Palmieri
authors.forename: M
authors.initials: M
authors.lastname: Franca
authors.forename: F
authors.initials: F
authors.lastname: Uzal
authors.forename: M
authors.initials: M
authors.lastname: Anderson
authors.forename: B
authors.initials: B
authors.lastname: Barr
authors.forename: L
authors.initials: L
authors.lastname: Woods
authors.forename: J
authors.initials: J
authors.lastname: Moore
authors.forename: P
authors.initials: P
authors.lastname: Woolcock
authors.forename: H L
authors.initials: HL
authors.lastname: Shivaprasad
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D001681:Biological Assay / Q000662:veterinary; D001715:Bird Diseases / Q000473:pathology / Q000821:virology*; D002642:Chick Embryo; D007150:Immunohistochemistry / Q000662:veterinary; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D011563:Psittaciformes; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms; D014901:West Nile Fever / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000956:Antigens, Viral; D012367:RNA, Viral