Lipid storage disease in 4 sibling superb birds-of-paradise (Lophorina superba).

Pedigree analysis, clinical, gross, microscopic, ultrastructural, and lipidomic findings in 4 female superb bird-of-paradise (SBOP, Lophorina superba) siblings led to the diagnosis of a primary inherited glycerolipid storage disease. These birds were the offspring of a related breeding pair (inbreeding coefficient = 0.1797) and are the only known SBOPs to display this constellation of lesions. The birds ranged from 0.75 to 4.3 years of age at the time of death. Two birds were euthanized and 1 died naturally due to the disease, and 1 died of head trauma with no prior clinical signs. Macroscopic findings included hepatomegaly and pallor (4/4), cardiac and renal pallor (2/4), and coelomic effusion (1/4). Microscopic examination found marked tissue distortion due to cytoplasmic lipid vacuoles in hepatocytes (4/4), cardiomyocytes (4/4), renal tubular epithelial cells (4/4), parathyroid gland principal cells (2/2), exocrine pancreatic cells (3/3), and the glandular cells of the ventriculus and proventriculus (3/3). Ultrastructurally, the lipids were deposited in single to coalescing or fused droplets lined by an inconspicuous or discontinuous monolayer membrane. Lipidomic profiling found that the cytoplasmic lipid deposits were primarily composed of triacylglycerols. Future work, including sequencing of the SBOP genome and genotyping, will be required to definitively determine the underlying genetic mechanism of this disease.

Retrospective and prospective studies of transmissible viral proventriculitis in broiler chickens in Brazil.

We investigated the occurrence and pathologic findings of transmissible viral proventriculitis (TVP) associated with the chicken proventricular necrosis virus (CPNV) in commercial broiler chickens in southeastern Brazil. Seventy-three broilers, 25-36 d old, with a history of reduced growth, were referred to our veterinary pathology services from 2013 to 2017. Broilers were clinically examined, weighed, and euthanized for postmortem examination. Broilers of different ages with proventricular histologic lesions were positive for CPNV by RT-PCR; however, the intensity of histologic lesions was higher among 33-d-old animals, and viral RNA detection was more frequent among those that were 28 d old. In the proventriculi of 35 of 73 (48%) broilers, lesions were characterized by glandular epithelial necrosis, lymphoplasmacytic and histiocytic infiltrates, and metaplasia of glandular epithelium to ductal epithelium. In 24 of 73 (36%) broilers with histologic TVP-compatible lesions, CPNV was detected by RT-PCR for the viral protein 1 (VP1) gene. Broilers with histologic lesions were lighter than expected compared to the Cobb 500 standard weight. TVP has not been reported previously in broiler chickens in Brazil, to our knowledge.

First Documentation of Nematode Dispharynx sp. in Scaled Quail.

Quail populations in the United States have been declining for several decades, and the role that parasites may be playing in this decline is not well understood. The goal of this study was to document novel parasites that inhabited the scaled quail, Callipepla squamata, of the Trans-Pecos ecoregion of Texas. To do this, quail were collected by hunter-harvest, night-netting, and funnel-trapping and were necropsied in the laboratory to determine the parasites they hosted. After analyzing 386 birds, we identified Dispharynx sp. in one of the samples. This specimen is the first to be officially documented in scaled quail.

Update on Avian Bornavirus and Proventricular Dilatation Disease: Diagnostics, Pathology, Prevalence, and Control.

Avian bornavirus (ABV) is a neurotropic virus that can cause gastrointestinal and/or neurologic signs of disease in birds. The disease process is called proventricular dilatation disease (PDD). The characteristic lesions observed in birds include encephalitis and gross dilatation of the proventriculus. ABV is widely distributed in captive and wild bird populations. Most birds infected do not show clinical signs of disease. This article is an update of the Veterinary Clinics of North America article from 2013: Avian Bornavirus and Proventricular Dilatation Disease: Diagnostics, Pathology, Prevalence, and Control.

Atrophic Proventriculitis Associated with Gravid Females of Tetrameres sp. (Nematoda: Tetrameridae) in the Magellanic Penguin (Spheniscus magellanicus) on the Coast of Brazil.

The present study offers the first description of proventriculitis associated with the presence of gravid female nematodes of the genus Tetrameres (Nematoda: Tetrameridae) in 3 juvenile Magellanic penguins (Spheniscus magellanicus) found dead on the coast of Brazil. This study broadens knowledge on parasites associated with these hosts and the real impact of this association.

Retrospective study on transmissible viral proventriculitis and chicken proventricular necrosis virus (CPNV) in the UK.

Chicken proventricular necrosis virus (CPNV) is a recently described birnavirus, which has been proposed to be the cause of transmissible viral proventriculitis (TVP). The understanding of the epidemiology of both the virus and the disease is very limited. A retrospective investigation on TVP and CPNV in broiler chicken submissions from the UK from between 1994 and 2015 was performed with the aims of assessing the longitudinal temporal evolution of TVP and CPNV, and to review the histological proventricular lesions in the studied chickens. Ninety-nine of the 135 included submissions (73.3%) fulfilled the TVP-diagnostic criteria, while the remaining 36 submissions (26.7%) displayed only lymphocytic proventriculitis (LP). The first detection of CPNV by PCR dated from 2009. Results showed a rise in the number of both TVP and positive CPNV RT-PCR submissions from 2009 with a peak in 2013, suggesting that they may be an emerging or re-emerging disease and pathogen, respectively. Twenty-two out of the 99 submissions displaying TVP lesions (22%) and four out of the 36 (11%) submissions with LP gave positive CPNV RT-PCR results, further supporting the association between CPNV and TVP and confirming that CPNV is present in a low proportion of proventriculi that do not fulfil the TVP-diagnostic criteria. In addition, intranuclear inclusion bodies were observed in 22 of the submissions with TVP. The vast majority of these cases (21 of 22, 96%) gave negative CPNV RT-PCR results, raising the question of whether a virus other than CPNV is responsible for some of these TVP-affected cases.RESEARCH HIGHLIGHTSTVP and CPNV have been present in British broilers since at least 1994 and 2009, respectively.TVP and CPNV seem to be an emerging and re-emerging disease and pathogen, respectively.CPNV was detected in proventriculi with both TVP and LP-lesions.Viruses other than CPNV may be responsible for some TVP-affected cases.

Morphological and Molecular Characterization of Larval and Adult Stages of Eustrongylides excisus (Nematoda: Dioctophymatoidea) with Histopathological Observations.

The genus Eustrongylides includes nematodes known as the etiological agent of the "big red worm disease." The aim of this work was to identify Eustrongylides spp. larvae from fish and adults from great cormorant (Phalacrocorax carbo) sampled at Lake Trasimeno, Italy, by morphological and molecular analysis. Histopathological description of the lesions in birds was also provided. We described adults of Eustrongylides excisus for the first time in Italy, and we also linked larval stages 3 and 4 to adults. The use of molecular tools combined with the traditional taxonomy will help the identification of the species, including species inquirendae. Moreover, molecular analysis can also help to investigate the role of intermediate and paratenic hosts, to deepen the knowledge about geographical distribution of the different Eustrongylides spp. and to define the zoonotic potential of E. excisus, which has not yet been identified as causal agent of human cases.

Emaciation and Sporadic Mortality in Older Laying Hens Caused by Intussusception of the Proventriculus.

Laying hens (n = 2267) ranging in age from 2 to 4 yr in a study evaluating ovarian cancer prevention were necropsied. Those that died or were culled during the 2-yr study (n = 1591) were necropsied weekly to determine the most probable cause of death or culling and cancer status. Hens surviving until the end of the study (n = 676) were euthanized and necropsied. Hens necropsied before and after a hen with proventricular intussusception served as cohorts (n = 38). Nineteen hens (13 dead, 6 culled) had intussusceptions of the proventriculus into the ventriculus. Mean age of affected hens was 154 wk (range 110-204 wk). None of the hens in the study had an intestinal intussusception, and none of the hens euthanized at the end of the study had a proventricular intussusception. Hens with proventricular intussusceptions were severely emaciated; mean body weights were 1040 and 1736 g for affected and cohort hens, respectively. Necropsy findings included prominent keel, marked muscle atrophy, generalized serous atrophy of fat, no visible proventriculus, esophagus directly entering the ventriculus, and an enlarged, spherical, firm ventriculus, which contained an invaginated, swollen, diffusely ulcerated proventriculus. Eighteen affected hens were anovulatory (94.7%) compared to 27 cohorts (71.1%). Severe, diffuse necrosis and ulceration of the proventricular mucosa was confirmed microscopically, but no etiologic agent was identified. In conclusion, proventricular intussusception of undetermined etiology was identified as a cause of sporadic emaciation, culling, and mortality in older laying hens.

Reporte de caso- Emaciación y mortalidad esporádica causadas por intususcepción del proventrículo en gallinas de postura maduras. Se realizaron necropsias de gallinas ponedoras (n=2267) de dos a cuatro años de edad en un estudio que evaluó la prevención del cáncer de ovario. Las aves que fueron eliminadas semanalmente durante el estudio de dos años (n=1591) se sometieron a la necropsia para determinar la causa más probable de muerte o de desecho y el estado de cáncer. Las gallinas que sobrevivieron hasta el final del estudio (n=676) se sacrificaron y se les realizó la necropsia. Las gallinas a las que se les practicó la necropsia antes y después de la intususcepción proventricular sirvieron como cohortes (n=38). Diecinueve gallinas (13 muertas y seis sacrificadas) tuvieron intususcepciones del proventrículo dentro de la molleja. La edad media de las gallinas afectadas fue de 154 semanas (con un rango de 110 a 204 semanas). Ninguna de las gallinas en el estudio mostró una intususcepción intestinal y ninguna de las gallinas sometidas a eutanasia al final del estudio tuvo una intususcepción proventricular. Las gallinas con intususcepciones proventriculares estaban severamente emaciadas; los pesos corporales medios fueron 1040 g y 1736 g para las gallinas afectadas y para las gallinas cohorte, respectivamente. Los hallazgos de la necropsia incluyeron la quilla de la pechuga prominente, atrofia muscular marcada, atrofia serosa de la grasa generalizada, no proventrículo visible, esófago entrando directamente en la molleja y una molleja esférica y firme, que contenía un proventrículo, invaginado, abultado y difusamente ulcerado. Dieciocho gallinas afectadas fueron anovulatorias (94.7%) en comparación con 27 cohortes (71.1%). La necrosis y la ulceración severas y generalizadas de la mucosa proventricular se confirmaron microscópicamente, pero no se identificó ningún agente etiológico. En conclusión, la intususcepción proventricular de etiología indeterminada se identificó como una causa de emaciación esporádica, sacrificio y mortalidad en gallinas ponedoras maduras.

Anatomopathological changes, quantification and distribution of Libyostrongylus spp. in regions of the proventriculus and ventriculus of naturally- and experimentally-infected ostriches.

Nematodes of the genus Libyostrongylus parasitize ostriches, causing high mortality rates. These nematodes are found in the proventriculus and ventriculus of ostriches, but little is known about their distribution and the possible anatomopathological changes they cause in the various regions of these organs. This paper describes the distribution and quantification of Libyostrongylus and pathological changes found in regions of the proventriculus and ventriculus of ostriches with high and low levels of both natural and experimental infection. Ostriches were necropsied and tissue samples from the distinct regions of both organs were analysed based on nematode counts and histopathology after staining with haematoxylin and eosin, Masson's trichrome or Alcian blue/PAS. The cranial and glandular regions of the proventriculus were the most parasitized. The ventriculus contained more nematodes in the caudal region. No macro- or microscopic pathological changes were observed in either of these organs of experimentally-infected birds. However, naturally-infected birds with high levels of infection presented proventriculus with macroscopic lesions and heterophilic infiltrates surrounding nematodes. In the glandular region of this organ, nematodes were located in the adenomeres of the secretory ducts, causing altered architecture and erosions and ulcerative lesions with damaged epithelium. Nematode eggs were found in the koilin layer of the middle and caudal regions of the ventriculus only of these birds. The pH of the regions assessed by Alcian blue/PAS staining changed from acidic in the proventriculus to more alkaline in the caudal region of the ventriculus. These data add knowledge to the biology of Libyostrongylus. RESEARCH HIGHLIGHTS The most parasitized areas were the cranial and glandular regions of the proventriculus. Naturally-infected birds with high levels of infection presented macro lesions in the proventriculus and damaged epithelium. Nematode eggs were found in the ventriculus. The proventriculus had an acidic pH, which turned alkaline towards the ventriculus.

Macrorhabdus ornithogaster Infection and Spontaneous Proventricular Adenocarcinoma in Budgerigars ( Melopsittacus undulatus).

Proventricular infection with the anamorphic, ascomycetous yeast Macrorhabdus ornithogaster and disease associated with infection (macrorhabdiosis) have been widely reported in budgerigars ( Melopsittacus undulatus). Proventricular adenocarcinoma has also been previously reported in this species. In a retrospective archival search of clinical cases submitted to a zoo animal and exotic pet pathology service between 1998 and 2013, a total of 28 128 avian submissions were identified, which included 1006 budgerigars kept in zoos or aviaries or as pets. Of these budgerigars, 177 were identified histologically as infected with M. orthithogaster at the time of necropsy. Histologic examination of tissues from budgerigars infected with M. orthithogaster identified an apparent continuum in the development of proventricular isthmus lesions associated with M. ornithogaster that included inflammation, mucosal hyperplasia, glandular dysplasia, and adenocarcinoma. Proventricular adenocarcinoma was identified histologically in 21 budgerigars. Budgerigars with proventricular adenocarcinoma were significantly more likely to have macrorhabdiosis than budgerigars without proventricular adenocarcinoma. Based on odds ratios for archival data, budgerigars were 41 times (95% confidence interval [CI], 33-52) more likely to have macrorhabdiosis than other avian species and 19 times (95% CI, 11-33) more likely to have proventricular adenocarcinoma than other birds. Budgerigars were 323 times (95% CI, 42-2490) more likely to be affected by both diseases simultaneously compared with other avian species. These findings suggest that macrorhabdiosis may be an associated factor for proventricular adenocarcinoma, although the explanation for this statistically significant correlation remains unknown and further investigation is warranted.

Characterization of an Unusual Mesenchymal Tumor in the Proventriculus of a Free-ranging Red-tailed Hawk (Buteo jamaicensis).

An adult, female red-tailed hawk (Buteo jamaicensis) was presented for examination after being found unable to fly on a private citizen's property. Further diagnostic testing revealed a vascular, soft tissue mass arising from the serosal surface of the proximal proventriculus. Postmortem histological and immunohistochemical examination of the mass revealed an unusual mesenchymal tumor with features consistent with a leiomyoma or low-grade gastrointestinal stromal tumor.

T-cell Thymic Lymphoma With Proventricular Metastasis in a Florida Scrub Jay ( Aphelocoma coerulescens).

An adult, wild-caught, female Florida scrub jay ( Aphelocoma coerulescens) was evaluated because of an observable mass on the ventral neck. Initial physical examination and diagnostic tests were performed, which revealed a subcutaneous mass. Surgical removal of the mass was attempted, but the bird died during surgery. Results of necropsy and histopathologic evaluation identified the mass as thymic lymphoma with proventricular metastasis. Immunohistochemical staining revealed strong cytoplasmic immunoreactivity for CD3 in the thymic mass and within the predominant lymphoid population in the serosal proventricular masses, which confirmed metastasis of T-cell lymphoma. To our knowledge, this is the first report of T-cell thymic lymphoma in a wild Florida scrub jay.

Proventricular dilatation disease (PDD) outbreak in blue-and-gold macaws (Ara ararauna) in the State of Santa Catarina, southern Brazil / Surto de doença da dilatação proventricular em araras-canindé (Ara ararauna) no estado de Santa Catarina, sul do Brasil

Proventricular dilatation disease (PDD) is a lethal and important disease of captive psittacine birds, and affects a wide range of species, including endangered ones, and lacks an effective treatment. This report describes PDD in three blue-and-gold macaws (Ara ararauna) in southern Brazil. All three macaws originated from the same aviary and presented similar clinical signs including anorexia, apathy, emaciation and prostration. At necropsy, one of the macaws presented an enlarged proventriculus. Histologically, lymphoplasmacytic infiltrates was observed in the ganglia and nerves of the esophagus, crop, proventriculus, ventriculus, heart, adrenal glands, and adrenal medulla of all three cases. Two macaws had meningoencephalomyelitis and one had myocarditis. Immunohistochemistry identified PaBV antigen in the brain, proventricular, ventricular ganglia, and epicardial ganglia, and cardiomyocytes of all three macaws.(AU)

A doença da dilatação proventricular (PDD) e uma importante e fatal doença de psitacídeos de cativeiro, que afeta uma grande variedade de espécies e não tem um tratamento efetivo até o momento. Este relato descreve PDD em três araras canindé (Ara ararauna) no sul do Brasil. Todas as três araras eram provenientes do mesmo criatório e apresentaram sinais clínicos semelhantes incluindo anorexia, apatia, emaciação e prostração. Na necropsia, uma das araras apresentou proventrículo dilatado. No exame histopatológico, infiltrados linfoplasmacitários foram observados em gânglios e nervos do esôfago, inglúvio, proventrículo, moela, coração, glândulas adrenais e rins de todos os casos. Adicionalmente, meningoencefalomielite foi observada em duas araras e miocardite em uma. A imuno-histoquímica identificou antígenos de PaBV no encéfalo, coração, proventrículo e moela de todos os casos.(AU)

Identification of Transmissible Viral Proventriculitis (TVP) in broiler chickens in Poland.

The aim of the study was to investigate the possibility of Transmissible Viral Proventriculitis (TVP) occurrence in broiler chickens in Poland. In march 2016 proventriculi samples were collected from broiler chickens showing poor uniformity and decreased body weight, accompanied by enlarged proventriculi. Histopathological examination of affected proventriculi revealed typical lesions associated with TVP (vacuolar degeneration and necrosis of glandular epithelium, replacement of glandular epithelium by hyperplastic ductal epithelium and moderate to severe lymphocytic infiltration). To our best knowledge, up to date there is no report indicating the presence of TVP in Poland nor in Central and Eastern Europe.

Proventriculitis Associated with Cryptosporidium baileyi in a Snowy Owl (Bubo scandiacus) and Its Epidemiological Investigation.

We describe an unusual case of proventriculitis associated with Cryptosporidium baileyi in a 7-wk-old snowy owl (Bubo scandiacus) chick kept at a zoo. Necropsy of this animal revealed diffuse mucosal thickening of the proventriculus. Subsequent histopathological examinations of the proventriculus showed marked ductal epithelial hyperplasia with intestinal metaplasia and severe inflammatory cell infiltration in the lamina propria and submucosa. These lesions were associated with numerous periodic-acid-Schiff-positive cryptosporidia-like protozoan parasites. Moreover, oocysts found within the lamina propria had a noticeably thicker wall and displayed Ziehl-Neelsen-positive test results. PCR sequencing analyses of the 18S rDNA, actin, and 70 kDa heat shock protein gene loci identified the protozoan to be C. baileyi, of which two novel sets of primers were designed for use with formalin-fixed paraffin-embedded tissue. An epidemiological survey was carried out at the zoo to investigate the source of infection, but all owl species surveyed proved negative for cryptosporidiosis. It is most likely that small animal vectors such as wild birds or rodents were responsible for this particular lethal case. This is the first report of C. baileyi associated with proventriculitis and also the first report of cryptosporidiosis in a raptor species in Asia.

Evaluation of gastroscopy and biopsy of the proventriculus and ventriculus in pigeons (Columba livia).

OBJECTIVE To evaluate the efficacy and safety of gastroscopy and biopsy of the proventriculus and ventriculus in pigeons (Columba livia). ANIMALS 15 adult pigeons. PROCEDURES Each pigeon was anesthetized, and the upper gastrointestinal tract (from the cervical portion of the esophagus to the ventriculus) was endoscopically evaluated by use of a rigid endoscope inserted orally. Saline (0.9% NaCl) solution was orally infused to achieve lumen dilation and visibility. Two mucosal biopsy specimens were collected from each of the proventriculus and ventriculus, histologically evaluated, and graded for crush artifacts and depth. Pigeons were monitored for adverse effects for 3 to 6 days after the procedure, after which they were euthanized for necropsy. RESULTS Gastroscopy via the oral approach provided excellent visibility of the lumen and mucosal surfaces of the proventriculus and cranial portion of the ventriculus and was safe provided that appropriate precautions were taken. Two intraoperative deaths occurred at the beginning of the study; following procedure refinement, no additional deaths occurred. No major adverse effects of the procedure were detected in the remaining 13 pigeons during the postoperative monitoring period or at necropsy. Diagnostic quality of proventriculus specimens was adequate for 10 of 13 pigeons. Eight of 13 ventriculus specimens were of inadequate quality, and only 3 were of adequate quality. CONCLUSIONS AND CLINICAL RELEVANCE Gastroscopy was useful for evaluating the lumen and mucosal surface of the proventriculus and ventriculus in pigeons, and biopsy of those organs was safely performed with the appropriate technique. Further evaluation of these techniques is needed in birds with clinical disease and birds of other species.

Detection of transmissible viral proventriculitis and chicken proventricular necrosis virus in the UK.

Increasing evidence suggests that a new birnavirus, named chicken proventricular necrosis virus (CPNV), is the aetiological agent of transmissible viral proventriculitis (TVP). The present work aimed to explore the possible presence of both TVP and CPNV in the UK. Forty-four chickens showing TVP-compatible gross lesions were classified into three groups based on the histological lesions: (i) TVP-affected chickens: lymphocytic infiltration and glandular necrosis (n = 15); (ii) lymphocytic proventriculitis (LP)-affected chickens: lymphocytic infiltration without necrosis (n = 18); and (iii) without proventriculitis (WP): no lymphocytic infiltration or necrosis (n = 11). Nine proventriculi (seven out of 15 corresponding to TVP, and two out of 11 corresponding to LP) were positive for CPNV by reverse transcriptase polymerase chain reaction (RT-PCR). These results support the previously suggested idea of CPNV as causative agent of TVP. Moreover, these data show that CPNV can also be detected in a number of cases with LP, which do not fulfil the histological TVP criteria. Phylogenetic analysis of partial sequences of gene VP1 showed that British CPNV sequences were closer to other European CPNV sequences and might constitute a different lineage from the American CPNV. TVP cases with negative CPNV PCR results may be due to chronic stages of the disease or to the reduced PCR sensitivity on formalin-fixed paraffin-embedded tissues. However, involvement of other agents in some of the cases cannot totally be ruled out. As far as the authors are aware, this is the first peer-reviewed report of TVP as well as of CPNV in the UK, and the first exploratory CPNV phylogenetic study.

Parrot Bornavirus (PaBV)-2 isolate causes different disease patterns in cockatiels than PaBV-4.

Psittaciform 1 bornavirus (PaBV) has already been shown to be the aetiologic agent of proventricular dilatation disease, a significant disease of birds. However, the pathogenesis of PaBV infection has not yet been resolved and valid data regarding the pathogenicity of different PaBV species are lacking. Thus, the present study was aimed to characterize the influence of two different PaBV species on the course of disease. Eighteen cockatiels were inoculated intracerebrally (i.c.) or intravenously (i.v.) with a PaBV-2 isolate under the same conditions as in a previous study using PaBV-4. Birds were surveyed and sampled for 33 weeks to analyse the course of infection and disease in comparison to that of PaBV-4. Similar to PaBV-4, PaBV-2 induced a persistent infection with seroconversion (from day 6 p.i. onwards) and shedding of viral RNA (from day 27 p.i. onwards). However, in contrast to PaBV-4, more birds displayed clinical signs and disease progression was more severe. After PaBV-2 infection, 12 birds exhibited clinical signs and 10 birds revealed a dilated proventriculus in necropsy. After PaBV-4 infection only four birds revealed clinical signs and seven birds showed a dilatation of the proventriculus. Clinically, different courses of disease were observed after PaBV-2 infection, mainly affecting the gastrointestinal tract. This had not been detected after PaBV-4 infection where more neurological signs were noted. The results provide evidence for different disease patterns according to different PaBV species, allowing the comparison between the infection with two PaBV species, and thus underlining the role of viral and individual host factors for disease outcome.

Runting Stunting Syndrome Associated with Transmissible Viral Proventriculitis in Broiler Chickens.

This report describes an outbreak of transmissible viral proventriculitis (TVP) associated with runting stunting syndrome (RSS) in 25- and 28-day-old broiler chickens, in which chicken proventricular necrosis virus (CNPV) was detected. Clinical signs included poor uniformity, very small birds for their age, increased mortality, and culling of smaller birds. Almost all birds necropsied exhibited moderate to severely enlarged proventriculi with diffusely pale serosa and thickened walls. Microscopically the proventriculi had lesions of degeneration and necrosis of the epithelium of the proventricular glands, accompanied by lymphocytic inflammation and glandular hyperplasia, with occasional formation of lymphoid nodules within the glandular parenchyma. Immunohistochemistry staining for CPNV was positive. Positive staining was generally found in the cytoplasm of glandular epithelial cells in the form of finely granular brown pigment. CPNV RNA was detected in the proventriculi by reverse transcriptase-PCR (RT-PCR). Other findings included mild enteritis in a few birds and small bursa of Fabricius. Direct electron microscopy performed on the intestinal samples was negative for viral particles. RT-PCR analysis of bursae was positive for infectious bursal disease virus (IBDV). In conclusion, this report associates TVP with RSS by describing an outbreak in which TVP attributable to CPNV was the most commonly found lesionin chickens with a clinical history compatible with RSS. Therefore, TVP should be considered as a possible differential diagnosis in cases compatible with RSS.