Growth and metabolic characterization of Macrorhabdus ornithogaster. J Vet Diagn Invest 19:256–265 (2007). Macrorhabdus ornithogaster (M. ornithogaster) is an anamorphic ascomycetous yeast found only in the stomach of birds. Infection is often benign but has also been associated with disease in some species of birds under some circumstances. has been associated with a chronic wasting disease in budgerigars, canaries, and finches and an acute hemorrhagic gastritis in budgerigars and parrotlets. A stunting syndrome was noted in chickens naturally infected with M. ornithogaster, but these birds were also affected by a number of other pathogens.
Toxinotypes of Clostridium perfringens isolated from sick and healthy avian species. J Vet Diagn Invest 19:329–333 (2007). All C. perfringensisolates were classified as type A regardless of species or disease history. Although many isolates (from all avian groups) had the gene encoding the C. perfirngens beta2 toxin, only 54% produced the toxin in vitro when measured using Western blot analysis. Surprisingly, a large number of healthy birds (90%) carried CPB2-producing isolates, whereas over half of the cpb2-positive isolates from diseased birds failed to produce CPB2. These data from this investigation do not suggest a causal relationship between beta2 toxin and necrotic enteritis in birds.
Application of polymerase chain reaction fingerprinting to differentiate Ornithobacterium rhinotracheale isolates. J Vet Diagn Invest 19:417–420 (2007). Ornithobacterium rhinotracheale (ORT) is an infectious respiratory pathogen of chickens, turkeys, and wild birds. The disease caused by ORT is characterized by tracheitis, airsacculitis, and fibrinous pneumonia in severely affected birds.
Sarcocystis sp.-associated meningoencephalitis in a bald eagle (Haliaeetus leucocephalus). J Vet Diagn Invest 19:564–568 (2007). Protozoal meningoencephalitis -The predominant histologic lesion was lymphoplasmacytic and histiocytic meningoencephalitis involving the cerebrum and cerebellum. There was a marked segmental loss of granular cells and Purkinje cells, as well as segmental atrophy of the molecular layer in the cerebellum. Protozoal merozoites and schizonts were observed in the gray matter of the cerebellum. Ultrastructurally, the merozoites were classified as a species of Sarcocystis due to the lack of rhoptries. Immunohistochemistry of the agent revealed a positive reaction for Sarcocystis neurona, while sections were negative for Toxoplasma gondii and Neospora caninum.
Respiratory herpesvirus infection in two Indian Ringneck parakeets. J Vet Diagn Invest 20:235–238 (2008). Diffuse consolidation and red discoloration of the lungs, as well as thickened, congested air sacs. multifocal, necrotizing bronchitis, parabronchitis, and interstitial pneumonia. large syncytial cells with up to 15 nuclei. The nuclei of these syncytial cells often contained large, eosinophilic inclusion bodies, consistent with herpesvirus. Recently, a novel Psittacid herpesvirus strain was isolated from the mucosal papillomas of neotropical parrots and from cloacal and cutaneous papillomas of African grey parrots. However, there have been reports of a different herpesvirus of parakeets that has tropism for the lower respiratory tract, with no hepatic or significant upper-respiratory-tract involvement. One was from the United States, in a Bourke’s parakeet, and the other was from Japan. This virus is referred to as ‘‘respiratory herpesvirus of parakeets’’ and represents an unusual manifestation of herpesvirus- induced disease in parakeets. In these 2 parakeets, the herpes-like inclusion bodies were identified within epithelial cells and syncytial cells of the trachea, bronchi, parabronchi, air capillaries, and air sacs. Herpesvirus subfamilies include alpha-herpesviruses, beta-herpesviruses, and gamma-herpesviruses. Alpha-herpesviruses are associated with rapid viral replication, host cell lysis, and the ability to establish latent infection.5 An example of avian alpha-herpesvirus is Gallid herpesvirus 1 (family Herpesviridae, subfamily Alphaherpesvirinae, genus Iltovirus), commonly known as Infectious laryngotracheitis virus (ILTV) of chickens, which causes upper-respiratorytract infection manifested as necrotizing pharyngitis, laryngitis, tracheitis, and, occasionally, mild pneumonia.23. In Psittaciformes, there are several recognized diseases associated with avian alpha-herpesviruses. Infection with Psittacid herpesvirus 1 (PsHV-1), formerly known as Pacheco’s disease (PD), is characterized by massive hepatic necrosis with formation of syncytial cells.18 Amazon tracheitis virus (ATV) is a cause of upper-respiratory-tract lesions similar to ILTV in chickens.18 There are several other herpesviruses associated with more chronic, non–lifethreatening skin and/or mucosal lesions. It is speculated that the feather abnormalities referred to as ‘‘feather dusters’’ in European Budgerigars are caused by a herpesvirus.
Hepatic hemorrhage, hemocoelom, and sudden death due to Haemoproteus infection in passerine birds: eleven cases. J Vet Diagn Invest 20:304–313 (2008). A promiscuous genotype of Haemoproteus capable of undergoing host switching on a familial level was identified. This protozoan caused severe disease with high mortality in 6 species of exotic passerine birds housed in California at the San Diego Zoo. Necropsy findings consisted of hemocoelom and irregularly scattered areas of hemorrhage and hepatocellular necrosis. Affected areas of liver contained solitary protozoal megaloschizonts in varied states of degeneration and peripheral nonsuppurative inflammation. No other parasite life stages were found in parenchymal organs or blood smears.
Interaction of ionophore and vitamin E in knockdown syndrome of turkeys. J Vet Diagn Invest 20:472–476 (2008). Turkeys with knockdown syndromehad myopathy of skeletal muscles, but no lesions in the myocardium. Generally, concentration of monensin in serum was highest in turkeys diagnosed with knockdown syndrome given more than 90 mg/kg of monensin in the diet. Vitamin E concentrations in the livers were statistically higher in healthy turkeys fed a diet free of monensin than in the livers of birds from the 3 groups exposed to monensin. This suggests that the concentration of monensin in serum positively correlates to the severity of clinical signs and pathology and to the amount of monensin in the feed. The current study also suggests that monensin in the feed could induce lower concentrations of vitamin E in the liver of turkeys and can predispose the turkeys to knockdown syndrome.
Diffuse intestinal T-cell lymphosarcoma in a yellow-naped Amazon parrot (Amazona ochrocephala auropalliata). J Vet Diagn Invest 20:656–660 (2008). Lymphosarcoma (LSA) is the most commonly reported lymphoid neoplasm in parrots.
Pathology of Natural Infections by H5N1 Highly Pathogenic Avian Influenza Virus in Mute (Cygnus olor) and Whooper (Cygnus cygnus) Swans. Vet Pathol 44:137–143 (2007). multifocal hemorrhagic necrosis in the pancreas, pulmonary congestion and edema, and subepicardial hemorrhages. Major histologic lesions were acute pancreatic necrosis, multifocal necrotizing hepatitis, and lymphoplasmacytic encephalitis with neuronal necrosis. Adrenals displayed consistently scattered cortical and medullary necrosis. In spleen and Peyer’s patches, mild lymphocyte necrosis was present. In the brain, a large number of neurons and glial cells, especially Purkinje cells, showed immunostaining.
Pathology and Virus Tissue Distribution of Turkey Origin Reoviruses in Experimentally Infected Turkey Poults. Vet Pathol 44:185–195 (2007). bursal atrophy characterized by lymphoid depletion and increased fibroplasia between the bursal follicles. Both IHC and ISH revealed viral antigen and RNA in the surface epithelial cells of the bursa, in macrophages in the interstitium of the bursa and, to lesser degree, in splenic red pulp macrophages and intestinal epithelial cells. The lymphoid depletion observed in the bursa appears to be the effect of an indirectly induced apoptosis and would most likely result in immune dysfunction in poults infected with TRV.
Pathologic Findings of Highly Pathogenic Avian Influenza Virus A/Duck/Vietnam/12/05 (H5N1) in Experimentally Infected Pekin Ducks, Based on Immunohistochemistry and In Situ Hybridization. Vet Pathol 44:635–642 (2007). Clinical signs – conjunctivitis and slight depression, severe neurologic signs consisting of torticollis, incoordination, tremors, and seizures. Gross lesions- hemorrhages in the duodenum, ceca, proventriculus, ventriculus, trachea, pancreas, and brain. Histologic lesions, as well as immunohistochemistry positivity, were recorded in the pancreas and brain.
Fatal Coxiellosis in Swainson’s Blue Mountain Rainbow Lorikeets Vet Path 2008 Mar: Clinical signs = head pressing, hemiparesis, seizures, obtunded mentation. Grossly= hepatomegaly, splenomegaly; Histo= disseminated microgranulomas in the liver, spleen, and brain, and lymphohistocytic perivascular encephalitis and cephalic vasculitis. Bacteria were Gimenez and PAS positive.
Feather-picking Psittacines: Histopathology and Species Trends Vet Path 2008 May: Inflammatory skin disease was diagnosed in 210 birds, and traumatic skin disease was diagnosed in 198 birds. The inflammatory cells associated with the lesions were typically lymphocytes and occasionally plasma cells, histiocytes, and granulocytes. The pattern and the cellular constitu- ents of the inflammation are most suggestive of cutaneous delayed type hypersensitivity.
Cutaneous Pythiosis in a Nestling White-faced Ibis. Vet Pathol 45:538–541 (2008). multifocal skin ulceration. cutaneous infection by the oomycete Pythium insidiosum. The microscopic features of the disease, including intense, necrotizing eosinophilic and granulomatous inflammation, are similar to those previously described in mammals. oomycete hyphae that are blunt to sinuous, pauciseptate, and range from 3 to 7 um in diameter.
Naturally Occurring Multiple Perineuriomas in a Chicken (Gallus domesticus). Vet Pathol 45:685–689 (2008). Nerves of the lumbosacral plexus, brachial plexus, and spinal ganglia. Diffuse proliferations of spindle cells with characteristic onion bulb–like structures around residual axons. The spindle cells were immunohistochemically positive for glucose transporter 1 (GLUT1) and negative for S-100 a/b protein. Neoplasms that originate from the perineurium (perineuriomas) are classified into 2 types, intraneural perineurioma and extraneural/soft tissue perineurioma. Schwannomas consist of tumors composed of Schwann cells that are arranged in streams of elongated spindle cells. Neurofibromas are characterized by proliferation of fibroblasts or perineurial cells in addition to Schwann cells.
Ganglioneuroma of the Brachial Plexus in Two Cockatiels (Nymphicus hollandicus). Vet Pathol 45:690–692 (2008). Ganglioneuroma involving the brachial plexus, paraspinal ganglia, and cervical-thoracic spinal cord. unilateral, firm, gelatinous white to tan multilobular mass at the thoracic inlet expanding and partially obliterating the brachial plexus and cervical spinal cord. Histologically, the masses were characterized by a locally infiltrative neoplasm comprised of spindyloid cells forming streams and sheets with interspersed distinct neuron cell bodies consistent with ganglion cells. Ganglioneuromas are composed of both mature ganglion cells and nerve fascicles with axons, Schwann cells, fibroblasts, and other connective tissue elements.
Pathologic and Immunohistochemical Studies of Newcastle Disease (ND) in Broiler Chickens Vaccinated with ND: Severe Nonpurulent Encephalitis and Necrotizing Pancreatitis. Vet Pathol 45:928–933 (2008). Macroscopically, bursal atrophy, white spots on the pancreas, and discoloration and enlargement of kidneys and spleen were observed in the broilers. Histologically, perivascular cuffing, neuronal degeneration and necrosis, and glial proliferation were present in the cerebrum, cerebellum, and medulla oblongata. There was extensive rarefaction and malacia in the parenchyma of severely affected brains. There were extensive degeneration, necrosis, and depletion of acinar cells in the pancreas. ND virus isolated from the present cases did not cause encephalitis or pancreatitis in specific-pathogen- free chickens, but it induced mortality with hepatocytic sinusoidal thrombi, splenic necrosis, lymphoid necrosis and depletion, and conjunctival hemorrhage. (Vaccine attenuated the infection making it not as lethal and altering the tropism.)
Sarcocystis falcatula–associated encephalitis in a free-ranging great horned owl (Bubo virginianus). J Vet Diagn Invest 21:283–287 (2009). Markedgranulomatous encephalitis with focal brainstem malacia was detected microscopically. The brainstem was the most severely affected brain location and the only place in which schizonts and merozoites, morphologically compatible with Sarcocystis spp., were detected. Immunohistochemistry with the use of polyclonal antisera indicated the presence of Sarcocystis falcatula. The species identification of the protozoa as S. falcatula was confirmed by polymerase chain reaction.
Evidence for Clostridium septicum as a primary cause of cellulitis in commercial turkeys. J Vet Diagn Invest 21:374–377 (2009). Turkey cellulitis is an acute diffuse infection of the dermis and subcutaneous tissue with edema and moderate diffuse heterophil infiltration of the subcutis. Clostridium septicum > Clostridium perfringens > Clostridium sordelli.
Selective Vulnerability of Peripheral Nerves in Avian Riboflavin Deficiency Demyelinating Polyneuropathy: Riboflavin deficiency in young, rapidly growing chickens produces selective injury to peripheral nerve trunks, with relative sparing of spinal nerve roots and distal nerve branches to muscle and skin.
Bilateral Nocardial Endophthalmitis in a Prothonotary Warbler (Protonotaria citrea): severe pyogranulomatous endophthalmitis with retinal necrosis and detachment with intralesionalbranching, gram-positive, beaded, filamentous bacteria formed a thick mat attached to the retinal pigmented epithelium and extending into the pecten.
Subgroup J Avian Leukosis Virus–Induced Histiocytic Sarcomatosis Occurs Only in Persistently Viremic but Not Immunotolerized Meat-type Chickens: histiocytic sarcomatosis was observed only in persistently viremic, meat-type chickens that were inoculated at hatch, but not in immunotolerized (persistently viremic, with no antibodies), in ovo inoculated chickens. However, the immunotolerized, in ovo inoculated chickens developed a high incidence of myeloid tumors. Spleen was consistently in all cases of ALV-J induced HS, other organs involved were lung, liver, bone marrow and kidney.
Oligoastrocytoma of the Brain in a Hooded Crane: The tumor was composed of 2 discrete components that resembled oligodendroglioma and astrocytoma. Oligodendrogliomatous cells were partially immunoreactive for vimentin and myelin basic protein, and the astrogliomatous component were vimentin, S-100, GFAP positive.
Adenoviral gizzard erosions in Italian chicken flocks. Veterinary Record (2009) 164, 54-56. Gross Lesions: gizzards- erosions variable in size, brown to black colour . Histolopath: Multifocal loss or degeneration of the cuticle of the koilin layer, ulcers or sloughing/flattening of glandular epithelium of the gizzards, associated with heterophils, macrophages, lymphocytes and plasma cells. Large intranuclear basophilic inclusion bodies in the enlarged nuclei of degenerating epithelial cells . Intranuclear and perinuclear positive immunolabelling for fAdV-1. fAV-2 is Marble Spleen Disease of pheasants and related to Hemorrhagic enteritis of turkeys
Pathogenesis of Newcastle disease (ND) in commercial & specific pathogen-free (SPF) turkeys experimentally infected with isolates of different virulence. pp168-78. March 2006 COVER JTP
– NCD < Avian paramyxovirus type 1 (Avulavirus)
– fusion protein major determinant of virulence; hemagglutinin-neuraminidase also contributes
– lentogenic (low virulence): no CS
– mesogenic (moderate virulence): depression in some birds; some SPF w/mild myocarditis
– velogenic (hi virulence, neurotropic or viscerotropic): severe depression + neuro signs
– lesions mostly in lymphoid, intestinal, & CNS tissues
– dz in turkeys less severe than in chickens
lentogenic = mild or inapparent respiratory infection
mesogenic = low mortality, acute respiratory dz, neuro signs in some
NVND = respiratory & neuro signs w/hi mortality
VVND = acute lethal, necrohemorrhagic lesions esp. in GIT
– IHC positive cells: lymphocytes, monocytes, myocytes, air sac epithelium,
Dendrites of Purkinje cells and glial cells in the molecular layer of the cerebellum
Cerebellar hypoplasia associated w/an avian leukosis virus inducing fowl glioma. pp294-301. May 2006 AR
· Fowl glioma-inducing virus (FGV) (in ALV subgroup A)® astrocytoma, perineurioma
· Chickens inoculated w/FGV via yolk sac on day 7 incubation® cerebellar hypoplasia
· Apoptotic granular cells were frequently observed in external granular layer and molecular layer
· Cell loss induced obstruction of granular cell migration and disarrangement of Bergmann’s fibers in the molecular layer
Mycotic pododermatitis and mycotic pneumonia in commercial turkey poults in northern California. J Vet Diagn Invest 21:554–557 (2009). The unique feature of this case was the colonization of footpad epidermis and subcutis by fungal hyphae in commercial turkey species. Cryptococcus saitoi and Cladosporium and Cudoniella species were identified. The fungi identified from lungs were Aspergillus species, most closely matching Aspergillus flavus and Arxiozyma telluris.
An Epizootic of Avian Pox in Endemic Short-toed Larks (Calandrella rufescens) and Berthelot’s Pipits (Anthus berthelotti) in the Canary Islands, Spain: The most common cutaneous form of avian pox involves the unfeathered parts of the body: legs, feet, face at the base of the beak, and eyelids. Lesions consist of epithelial hyperplasia of the epidermis resulting in proliferative, wartlike projections. With the diphtheritic form, caseous, necrotic lesions develop in the mucous membranes of the upper respiratory tract, mouth and pharynx. Light microscopic evaluation of affected tissues can confirm the presence of the typical large, solid or ringlike, eosinophilic intra-cytoplasmic inclusions known as Bollinger bodies.
Multiple Perineuriomas in Chicken: multiple enlargements of PNs in 11 chickens inoculated with an avian leukosis virus (ALV) causing so-called fowl glioma. All chickens clinically exhibited progressive leg paralysis. Lumbosacral plexus, brachial plexus, and/or spinal ganglion were commonly affected, and these nerves contained a diffuse proliferation of spindle cells arranged concentrically in characteristic onion bulb–like structures surrounded by residual axons and myelin sheaths. IHC negative for S-100/ß protein. EM: cells have short bipolar cytoplasmic processes, occasional cytoplasmic pinocytotic vesicles, and discontinuous basal laminae. 73% birds were positive with ALV with PCR.
Pathology of Highly Pathogenic Avian Influenza Virus (H5N1) Infection in Canada Geese (Branta canadensis): Preliminary Studies. Vet Pathol 46:966–970 (2009). Immunohistochemistry was used to locate influenza A virus nucleoprotein in brain, spinal cord, respiratory and digestive systems, pancreas, heart, and peripheral and parasympathetic nervous systems. HPAI virus replicates in endothelial cells throughout the vascular system during initial infection in chickens. Penetration of the blood-brain barrier by virus is followed by infection of neurons and glial cells, and concurrently virus is able to infect a wide variety of parenchymal cells in other organs. focal neuronal pycnosis and mild edema, usually near or surrounding a capillary (Fig. 1). Purkinje cell necrosis and gliosis was prominent in the cerebellum. Ependymal cells lining the ventricles of the brain and spinal canal (Fig. 2) were surrounded by a mild glial reaction, and focal gliosis w as present in some gray matter horns of the spinal cord. Significant viral damage also occurred in many other organs, including the heart, trachea, and pancreas.
Pathology and Virus Distribution in Chickens Naturally Infected with Highly Pathogenic Avian Influenza A Virus (H7N7) During the 2003 Outbreak in The Netherlands. Vet Pathol 46:971–976 (2009). Influenza virus antigen occurred in endothelial cells and mononuclear cells, parenchymal cells of heart, lung, kidney, pancreas, and trachea, often associated with multifocal inflammation and necrosis. edematous wattle skin. Virus histochemistry showed that this H7N7 virus attached to more endothelial cells in wattle skin than in other vascular beds.
West Nile virus detection in nonvascular feathers from avian carcasses. J Vet Diagn Invest 21:616–622 (2009). Feathers of corvid passeriforms had the highest sensitivity of detection (64%), followed by noncorvid passeriforms (43%), columbiforms (33%), and falconiforms (31%). Storing feathers for 1 year at 220uC or at ambient room temperature resulted in detection rates of infectious WNV of 16% and zero, respectively, but had no effect on detection rates of WNV RNA in a subset of matched feather pairs (47% for both storage temperatures). The efficacy of WNV detection in nonvascular feathers is greatly enhanced by testing multiple feathers.
Pathology of natural highly pathogenic avian influenza H5N1 infection in wild tufted ducks (Aythya fuligula). J Vet Diagn Invest 21:579–587 (2009).Gross: The most prominent gross lesions were mildly to moderately congested lungs , red-brown mottling of the pancreas, and moderately enlarged spleens The main histologic lesions associated with the presence of avian influenza antigen were found in the brain, pancreas, and upper respiratory tract. nonsuppurative encephalitis or meningo-encephalitis. There were multifocal areas of gliosis, neuronophagia, and occasional lymphocytes, as well as mild-to-moderate perivascular cuffs, with a predominance of macrophages and lymphocytes in both the gray and white matter. Neurons within these areas had degeneration or necrosis. In the nasal mucosa, a mild intraepithelial infiltration of heterophils, especially in the lamina propria and deeper parts of the epithelium. The lungs had marked congestion and hemorrhages. Fibrin thrombi were occasionally observed in smaller vessels and capillaries. Inflammatory changes were observed in the lungs of more than half of the cases (11/17) and ranged from mild infiltration of heterophils in parabronchi to severe inflammation, with necrofibrinous exudate and sloughed necrotic epithelial cells. Pancreatic lesions were dominated by severe, acute, multifocal-to-coalescing coagulative necrosis of the acini.
Histologic, Immunohistochemical, and Electron Microscopic Features of a Unique Pulmonary Tumor in Cockatiels (Nymphicus hollandicus): Six Cases. Vet Pathol 46:1100–1108 (2009). compact sheets of anaplastic round to polygonal cells. All tumors had a high mitotic index, and had occasional large clear to slightly basophilic intranuclear inclusions (cytoplasmic invaginations). Neoplastic cells stained positive for vimentin, lysozyme, and in 1 bird, pan cytokeratin. All 6 pulmonary neoplasms were negative for avian polyomavirus. may be poorly differentiated carcinomas of pulmonary or thymic origin.
Severe Histiolymphocytic and Heterophilic Bronchopneumonia as a Reaction to In Ovo Fowlpox Vaccination in Broiler Chicks. Veterinary Pathology 47(1) 177-180. Broiler chickens – neurological signs and mortality in chicks between 3 days and 10 days of age – use of a fowlpox-vectored infectious laryngotracheitis virus vaccine in ovo. Gross lesions -the lungs contained numerous tan or gray, opaque to translucent, 0.5- to 2.0-mm nodules in the parenchyma. Microscopic lesions – multifocal severe lymphohistiocytic and heterophilic bronchopneumonia. Immunohistochemistry was positive for fowlpox virus in macrophages and lymphocytes, and polymerase chain reaction on paraffin-embedded lung tissues was positive for a fowlpox vector virus commonly used as a vaccine. The cause of the neurological signs was not determined.
Intracellular yeasts in endothelial cells of a great blue heron (Ardea herodias). J Vet Diagn Invest 22:131–134 (2010). Intracellular organisms in the endothelial cells of several organs of an adult great blue heron (Ardea herodias) were identified as a yeast in the family accharomycetales based on ultrastructural morphology and sequence data from the ribosomal RNA operon. Morphologically similar organisms of
unknown identity have been described previously in Muscovy (Cairina moschata) and domestic (Anas platyrhynchos domestica) ducks. At
necropsy, the lungs were edematous and coelomic effusion,
pericardial effusion, and fibrin tags were present. pulmonary edema, expansion of interlobular septa with edema and inflammatory cells, and
distention of endothelial cells with many 1–2-mm basophilic organisms. Fewer intracellular organisms were variably present in endothelial cells in the liver, spleen, intestine, kidney, heart, and brain. ultrastructural studies, which showed budding of the organism and positive staining with periodic
acid–Schiff reaction (PAS).6 Attempts at fungal culture resulted in a sparse growth of a yeast-like organism; however, subcultures were not viable.