Search

Avian poxvirus infections typically manifest as 2 forms: cutaneous ("dry") pox, characterized by proliferative nodules on the skin, and diphtheritic ("wet") pox, characterized by plaques of caseous exudate in the oropharynx and upper respiratory and gastrointestinal tracts. Systemic spread of virus to visceral organs beyond the skin and mucous membranes is rarely reported. Out of 151 cases diagnosed with avian poxvirus over a 20-year period at a zoological institution, 22 were characterized as having systemic involvement based on histopathology and molecular findings. Gross lesions in systemic cases included soft white nodules scattered throughout the liver, spleen, and kidneys. Two histopathologic patterns emerged: (1) widespread histiocytic inflammation in visceral organs with intrahistiocytic viral inclusions and (2) severe, localized dry or wet pox lesions with poxvirus-like inclusions within dermal and subepithelial histiocytes. In situ hybridization targeting the core P4b protein gene confirmed the presence of poxvirus DNA within histiocytes in both patterns. Polymerase chain reaction was performed targeting the reticuloendothelial virus long terminal repeat (REV LTR) flanking region and the core P4b protein gene. Sequences of the REV LTR flanking region from all systemic pox cases were identical to a previously described condorpox virus isolated from an Andean condor with systemic pox. Sequences of the core P4b protein gene from all systemic pox cases grouped into cluster 2 of the B1 subclade of canarypox viruses. Systemic involvement of avian poxvirus likely occurs as a result of infection with certain strain variations in combination with various possible host and environmental factors., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

We report the successful treatment of poxvirus lesions in two juvenile American flamingos (Phoenicopterus ruber) with experimental low-dose intralesional ribavirin injection. In the first flamingo, the size and location of a beak verrucosity interfered with feeding, and after multiple surgical interventions, an experimental therapy of low-dose intralesional ribavirin was implemented with close blood parameter monitoring to minimize any potential side effects due to systemic antiviral administration. The second flamingo had a poxvirus lesion on the tibiotarsus, which recurred after unsuccessful conservative medical treatment and surgical intervention and a course of intralesional ribavirin therapy was implemented. Regression of the lesions in both flamingos commenced within 3 days of ribavirin treatment resulting in complete resolution within 6 weeks of onset of ribavirin treatment., (Published by Elsevier Ltd.)

Avipoxviruses have been recognised as significant pathogens in the conservation of numerous bird species. However, the vast majority of the avipoxviruses that infect wild birds remain uncharacterised. Here, we characterise a novel avipoxvirus, mudlarkpox virus (MLPV) isolated from an Australian passerine bird, mudlark (Grallina cyanoleuca). In this study, tissues with histopathologically confirmed lesions consistent with avian pox were used for transmission electron microscopy, and showed characteristic ovoid to brick-shaped virions, indicative of infectious particles. The MLPV genome was >342.7 Kbp in length and contained six predicted novel genes and a further six genes were missing compared to shearwaterpox virus-2 (SWPV-2). Subsequent phylogenetic analyses of the MLPV genome positioned the virus within a distinct subclade also containing recently characterised avipoxvirus genomes from shearwater, canary and magpie bird species, and demonstrated a high degree of sequence similarity with SWPV-2 (94.92%)., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Cormorant fishing is a traditional Japanese fishing method using captive Japanese cormorants (Phalacrocorax capillatus). Between June and July 2017, an avian pox outbreak was reported in captive cormorant populations throughout several distant cities in Japan. We examined the lesions obtained from two such affected cormorants, which were raised in distant cities. The affected cormorants were grossly characterized by the development of cutaneous nodules around the base of the beak. Histopathologically, these nodules consisted of marked epidermal hyperplasia with ballooning degeneration of spinous cells and eosinophilic intracytoplasmic inclusions (Bollinger bodies). The lesions displayed 4b core protein (P4b) of Avipoxvirus (APV) and DNA polymerase genes, which were detected by PCR. Moreover, the nucleotide sequences detected from both cormorants were found to be identical. No identical sequence was found in any international database. These findings suggest that both examined cormorants were infected with an identical APV, which has never been previously reported. According to the phylogenetic analysis, the detected sequences were observed to cluster in subclade A3, which consists mainly of the sequences detected from several marine birds, including other cormorant species. This observation suggests that the viruses might be maintained in Japanese cormorants in nature.

This study reports an outbreak of avian pox in a quarantine of canaries imported from Europe, with a mortality of 30% and clinical signs of dyspnea and blepharoconjunctivitis. During necropsy, beak cyanosis, serous blepharitis, caseous sinusitis, oropharyngitis, tracheitis, pulmonary edema, pneumonia, fibrinous airsacculitis, and splenomegaly were observed. Microscopically, edema, epithelial hyperplasia, hydropic degeneration, and vacuolated eosinophilic intracytoplasmic inclusion bodies were found; similar lesions were observed in the thymus, spleen, and other organs. The virus was isolated in chicken embryos, and it was identified and characterized using a sequence of 913 nucleotides of the DNA polymerase gene. Pathologic characteristics and molecular biology indicate the systemic presence of avian pox associated with an avipoxvirus of the B1 subgroup. Additionally, other lesions associated with Aspergillus sp., Macrorhabdus ornithogaster, and Isospora sp. were found, which could contribute to the high mortality. Canarypox virus should be considered a differential diagnosis in cases of dyspnea and high mortality in canary flocks.

Pigeons ( Columba livia ) are used in biomedical research for studies of vision, cognition, neuronal pathways, and spatial orientation. Because there are few commercial laboratory sources, research pigeons are typically acquired from local fancier breeders or bred onsite. For acquired pigeons, the health and vaccine status is often unknown. A juvenile pigeon, born onsite and living in an enclosed outdoor loft, presented with small, bleeding, wart-like lesions on the medial aspects of digits 1 and 4. Topical treatment was initiated. Within a week, 4 fledglings were reported for small, dark papular lesions on the face, head, neck, and beak, and shortly thereafter, 2 additional juvenile pigeons developed similar lesions. The fledglings were euthanized, and histologic examination revealed numerous intralesional eosinophilic cytoplasmic viral inclusions (Bollinger bodies) confirming a diagnosis of poxvirus infection, likely pigeon pox. Although usually self-limiting, pigeon pox can cause moderate to severe lesions in fledgling and juvenile birds. Vaccination with a modified live poxvirus labeled for chickens was used to create herd immunity to pigeon poxvirus. Since vaccination of our entire flock and implementation of more stringent health protocols, all lesions have resolved, and no new lesions have been noted.

A severely emaciated adult Steller's sea eagle (Haliaeetus pelagicus) was found dead with electrocution-induced severe wing laceration, and with multiple cutaneous pock nodules at the periocular regions of both sides nearby the medial canthi and rhamphotheca. Histopathological examination of the nodules revealed hyperplasia of the epidermis with vacuolar degeneration and intracytoplasmic inclusion bodies (Bollinger bodies). The proventriculus was severely affected by nematodes and was ulcerated. Nucleotide sequencing of a PCR-amplified product of Avipoxvirus 4b core gene revealed 100% identity to the sequence of Avipoxvirus derived from other eagle species. This report describes the first detection of Avipoxvirus clade A from a Steller's sea eagle.

Poxvirus infections have been reported in domestic, captive, and wild avian hosts including many raptor species. A wild Common Buzzard ( Buteo buteo) admitted to a wildlife veterinary clinic in Sardinia, Italy, showed multiple, wart-like proliferative cutaneous lesions on both legs. Histologically, there was ballooning degeneration and large intracytoplasmic inclusion bodies consistent with avipoxvirus (APV) infection. Diagnosis was confirmed by PCR detecting APV genes: P4b (locus fpv167), P35 (locus fpv140), and partial DNA polymerase. Phylogenetic analyses were performed to compare the detected virus with a panel of selected APVs. Analyses of P4b and DNA polymerase assigned the virus to clade A (fowlpox virus), subclade A7, grouping with many other APVs previously isolated in birds of prey. Further research should highlight the diversity of avian pox viral strains circulating among Common Buzzards as well as the phylogenetic role of locus fpv140 (P35) in comparison with the more-conserved P4b and DNA polymerase genes.

Poxvirus was the causative agent of two unusual outbreaks of proliferative glossitis in canary ( Serinus canaria forma domestica) breeders in the Northern Italy. A total of 45, 7-9-mo-old canaries were submitted in fair postmortem conditions to the Istituto Zooprofilattico Sperimentale delle Venezie at the beginning of November 2005 for diagnostic investigation. Birds belonged to two unrelated and geographically distant aviaries in northern Italy, herein identified as Aviary A and Aviary B. The two breeder flocks had both attended the same bird exposition held at the beginning of October and started experiencing an onset of high mortality 3 wk after the show. Twelve red factor-melanin canaries from Aviary A (Mantua) and 33 dominant white and recessive white canaries from Aviary B (Vicenza) were submitted for laboratory investigations. Clinical signs were unspecific and consisted of depression, ruffling of the feathers, epistaxis, and anorexia due to decreased feed and water intake. Postmortem findings revealed a severe increase in volume, thickening, and hardening of the tongue, which had turned pinkish to dark brown. No apparent gross lesions were noticed in integumentary, respiratory, and digestive systems or other internal organs. Histopathologic evaluation of the tongue revealed severe proliferation of the stratified squamous epithelium containing numerous large eosinophilic intracytoplasmic inclusion bodies (Bollinger bodies) displacing the nuclei of the cells peripherally. Severe ulceration of the surface epithelium, fibrinoheterophilic plaque formation, and moderate basal lymphoplasmacytic infiltrations were also associated with the proliferative lesion. Poxvirus was successfully isolated from the lesions in tissue cultures but not in specific-pathogen-free chicken embryonated eggs. Typical large, brick-shaped viral particles of 300-450 nm were also observed in affected tongues by transmission electron microscopy. This is the first report of multiple outbreaks of "poxvirus glossitis" in canaries.

The Waved Albatross (Phoebastria irrorata) is a critically endangered seabird in a rapidly shrinking population in the Galápagos Islands, Ecuador. The introduction of novel pathogens and parasites poses a threat to population persistence. Monitoring disease prevalence and guarding against the spread of such agents in endemic taxa are conservation priorities for the Galápagos, where recent increases in the prevalence of avian pox may have contributed to population declines and range contractions in other bird species. During November 2013-January 2014, we identified 14 Waved Albatross nestlings at our study site on Española Island with avian pox-like lesions and clinical signs. Other seabirds, landbirds, and adult Waved Albatrosses were apparently unaffected. Histopathology of tissue samples from five infected nestlings revealed inclusion bodies in all samples, consistent with avipoxvirus infection. We documented higher mortality (6 of 14 nestlings) in affected nestlings than in unaffected young in this small outbreak of avian pox, the first report of its kind in the world's only tropical albatross.

A total of 600 wild birds were analyzed for the causes of mortality in the Republic of Korea (ROK) from 2011 to 2013. Avian poxvirus (APV) infections were identified as the primary cause of mortality in 39% (29/74) Oriental Turtle Doves (Streptopelia orientalis). At necropsy, all 29 S. orientalis birds, of which, 76% (22/29) were juveniles, had severe diphtheritic lesions in their oral and nasal cavities and on their eyelids, which were the lesions of APV that resulted in mortality. We detected APV infection by chorioallantoic membrane inoculation and molecular study of the partial region of the P4b gene. All isolates belonged to the same APV strain and were identical to strains isolated from several different pigeon species in South Africa. Phylogenetically, the APV strain identified in S. orientalis belonged to subclade A2, which includes isolates from several species of pigeons from different parts of the world, including the United Kingdom, Germany, India, Egypt, Hawaii, Georgia, Hungary, South Africa, Tanzania, and the ROK. This identity indicated that this diphtheritic APV strain may be a potential pathogen of other pigeon species in the ROK and neighboring countries throughout the range of S. orientalis. However, reticuloendotheliosis virus insertion into the APV genome was not detected by PCR in any of the 29 APV infections. An identical strain of APV observed in S. orientalis was also detected in Culicoides arakawae (biting midge), with annual peak populations corresponding to the presence of APV in S. orientalis. Culicoides arakawae may be a primary vector of APV in S. orientalis. Active surveillance of APVs in wild birds and C. arakawae is needed to better understand the epidemiology of APVs, host-vector relationships, and its ecological effects on S. orientalis in the ROK.

Avian poxviruses (APV) are very large viruses spread worldwide in a variety of hosts. They are responsible for a disease usually referred to as pox, mainly characterized by nodular lesions on feather-free regions of the body. On May 2010, a young American flamingo (Phoenicopterus ruber) of the Lisbon Zoo (Portugal) developed a nodular lesion suggestive of poxvirus infection on its right foot. Avipoxvirus was isolated from the lesion and a fragment of the P4b-encoding gene was amplified by polymerase chain reaction. The nucleotide sequence of the amplicon was determined and analyzed. A close relationship (100% identity) was observed between the flamingo poxvirus and isolates from great bustard (Hungary 2005), house sparrow (Morocco 2009), MacQueen's bustard (Morocco 2011), and Houbara bustard (Morocco 2010 and 2011), suggesting interspecies transmission as a possible source of infection. To strengthen the investigation, the 5' and 3' ends of genes cnpv186 and cnpv 187, respectively, were also analyzed. The cnpv186-187 fragment exhibited 100% identity with MacQueen's bustard and Houbara bustard isolates, both from Morocco 2011. Phylogenetic analyses based in both fragments grouped the flamingo isolate consistently within clade B2 of canarypox. However, the phylogenetic relationships among the different representatives of avian poxviruses were more comprehensive in the tree based on the concatenated coding sequences of the cnpv186-187 fragment, rather than on the P4b-coding gene. The clearer displacement and distribution of the isolates regarding their host species in this last tree suggests the potential usefulness of this genomic region to refine avian poxvirus classification.

A flightless wild juvenile rock pigeon (Columba guinea) with pox-like lesions was picked up on the premises of the Faculty of Veterinary Science, University of Pretoria, Onderstepoort. The pigeon was housed overnight for possible treatment the following day but died before any other intervention could be instituted. At necropsy, coalescing masses of yellowish nodular cutaneous tumour-like lesions principally on the featherless areas were noticed on the dead pigeon's head as well as the beak. Histological examination of the sampled skin lesions revealed multifocal areas of hypertrophic and hyperplastic epidermal epithelial cells with eosinophilic intracytoplasmic inclusion bodies (Bollinger bodies). Extract from the lesion was processed and inoculated on the chorioallantoic membranes (CAM) of 11-day-old embryonated chicken eggs and this produced pocks on one of the CAM at day 7 post-inoculation. Electron microscopy confirmed the presence of poxvirus in the CAM with the pock lesions.

Globally, Avipoxvirus species affect over 230 species of wild birds and can significantly impair survival. During banding of nine grassland songbird species (n=346 individuals) in southwestern Wisconsin, USA, we noted species with a 2-6% prevalence of pox-like lesions (possible evidence of current infection) and 4-10% missing digits (potential evidence of past infection). These prevalences approach those recorded among island endemic birds (4-9% and 9-20% for the Galapagos and Hawaii, respectively) for which Avipoxvirus species have been implicated as contributing to dramatic population declines. Henslow's Sparrow Ammodramus henslowii (n=165 individuals) had the highest prevalence of lesions (6.1%) and missing digits (9.7%). Among a subset of 26 Henslow's Sparrows from which blood samples were obtained, none had detectable antibody reactive to fowlpox virus antigen. However, four samples (18%) had antibody to canarypox virus antigen with test sample and negative control ratios (P/N values) ranging from 2.4 to 6.5 (median 4.3). Of four antibody-positive birds, two had lesions recorded (one was also missing a digit), one had digits missing, and one had no signs. Additionally, the birds with lesions or missing digits had higher P/N values than did the antibody-positive bird without missing digits or recorded lesions. This study represents an impetus for considering the impacts and dynamics of disease caused by Avipoxvirus among North American grassland bird species.

A novel avipoxvirus caused diphtheritic lesions in the oesophagus of five and in the bronchioli of four Magellanic penguins (Spheniscus magellanicus) and also cutaneous lesions in eight Magellanic penguins housed in outdoor enclosures in a Rehabilitation Centre at Florianópolis, Santa Catarina State, Brazil. At the same time, another avipoxvirus strain caused cutaneous lesions in three Magellanic penguins at a geographically distinct Rehabilitation Centre localized at Vila Velha, Espírito Santo State, Brazil. Diagnosis was based on clinical signs, histopathology and use of the polymerase chain reaction (PCR). Clinical signs in the penguins included cutaneous papules and nodules around eyelids and beaks, depression and restriction in weight gain. The most common gross lesions were severely congested and haemorrhagic lungs, splenomegaly and cardiomegaly. Histological examination revealed Bollinger inclusion bodies in cutaneous lesions, mild to severe bronchopneumonia, moderate periportal lymphocytic hepatitis, splenic lymphopenia and lymphocytolysis. Other frequent findings included necrotizing splenitis, enteritis, oesophagitis, dermatitis and airsacculitis. Cytoplasmic inclusion bodies were seen within oesophageal epithelial cells in five birds and in epithelial cells of the bronchioli in four penguins. DNA from all samples was amplified from skin tissue by PCR using P4b-targeting primers already described in the literature for avipoxvirus. The sequences showed two different virus strains belonging to the genus Avipoxvirus of the Chordopoxvirinae subfamily, one being divergent from the penguinpox and avipoxviruses already described in Magellanic penguins in Patagonia, but segregating within a clade of canarypox-like viruses implicated in diphtheritic and respiratory disease.

Thirteen novel avipoxviruses were isolated from birds from different regions of South Africa. These viruses could be divided into six groups, according to gross pathology and pock appearance on chick chorioallantoic membranes (CAMs). Histopathology revealed distinct differences in epidermal and mesodermal cell proliferation, as well as immune cell infiltration, caused by the different avipoxviruses, even within groups of viruses causing similar CAM gross pathology. In order to determine the genetic relationships among the viruses, several conserved poxvirus genetic regions, corresponding to vaccinia virus (VACV) A3L (fpv167 locus, VACV P4b), G8R (fpv126 locus, VLTF-1), H3L (fpv140 locus, VACV H3L) and A11R-A12L (fpv175-176 locus) were analysed phylogenetically. The South African avipoxvirus isolates in this study all grouped in clade A, in either subclade A2 or A3 of the genus Avipoxvirus and differ from the commercial fowlpox vaccines (subclade A1) in use in the South African poultry industry. Analysis of different loci resulted in different branching patterns. There was no correlation between gross morphology, histopathology, pock morphology and phylogenetic grouping. There was also no correlation between geographical distribution and virus phenotype or genotype.

Poxviral infection was identified in a crimson rosella presented to the Australian Wildlife Health Centre (Victoria) in 2002, and from a second crimson rosella in 2008. Both cases were characterized by proliferative lesions on non-feathered skin. Routine histopathology identified intra-lesional epidermal changes consistent with those caused by poxvirus. Electron microscopy confirmed the presence of poxvirus in inclusions in the first case, and genetic analysis of DNA extracted from both cases found an identical viral genome that differs from all other known poxviruses. We conclude that this infection in crimson rosellas is caused by a previously unrecognized avian poxvirus endemic to this region of Australia, and with low virulence.

Case History: Nodular lesions were found on the skin of two immature brown kiwi (Apteryx mantelli) less than 6 months of age living freely on Ponui Island off the North Island of New Zealand. The lesions were observed during routine external examination undertaken as a part of the management of other research projects, one in 2006 and the other in 2011. Apart from the skin lesions, both birds showed no signs of illness and the lesions resolved spontaneously over a 2-month period., Pathological Findings: The first case showed several 3-mm diameter firm, brown nodules located on the skin below the hock of both legs. The second case had a single multinodular mass that measured 7×20 mm, on the base of the bill. A portion of the mass and scab samples were collected for diagnosis. Histological examination of the nodules revealed severe ballooning degeneration of keratinocytes and epithelial hyperplasia. Round eosinophilic structures resembling avipoxvirus (APV) intracytoplasmic inclusion bodies (Bollinger bodies) were observed in the layers of keratinocytes. In deeper layers of the epidermis, there was evidence of secondary bacterial growth and inflammation., Diagnosis: DNA was extracted from tissue samples and subjected to PCR analysis. Avipoxvirus 4b core protein gene was detected in both samples by PCR. Bootstrap analysis of APV 4b core protein gene revealed that APV isolates from two kiwi comprised two different subclades. One isolate displayed 100% sequence homology to subclade B1, and the other presented 100% sequence homology to subclade A3., Clinical Relevance: This study confirmed that kiwi are susceptible to APV infection and that at least two different strains of APV are present in the population examined. Since there is no information on the origin, virulence, or prevalence of APV in kiwi, a seroprevalence study would be useful to elucidate the degree of exposure and immune response to the disease. This would allow a more informed approach to risk management of the disease in wild and captive populations.

Avian pox is a viral disease with a wide host range. In Great Britain, avian pox in birds of the Paridae family was first diagnosed in a great tit (Parus major) from south-east England in 2006. An increasing number of avian pox incidents in Paridae have been reported each year since, indicative of an emergent infection. Here, we utilise a database of opportunistic reports of garden bird mortality and morbidity to analyse spatial and temporal patterns of suspected avian pox throughout Great Britain, 2006-2010. Reports of affected Paridae (211 incidents) outnumbered reports in non-Paridae (91 incidents). The majority (90%) of Paridae incidents involved great tits. Paridae pox incidents were more likely to involve multiple individuals (77.3%) than were incidents in non-Paridae hosts (31.9%). Unlike the small wart-like lesions usually seen in non-Paridae with avian pox in Great Britain, lesions in Paridae were frequently large, often with an ulcerated surface and caseous core. Spatial analyses revealed strong clustering of suspected avian pox incidents involving Paridae hosts, but only weak, inconsistent clustering of incidents involving non-Paridae hosts. There was no spatial association between Paridae and non-Paridae incidents. We documented significant spatial spread of Paridae pox from an origin in south-east England; no spatial spread was evident for non-Paridae pox. For both host clades, there was an annual peak of reports in August/September. Sequencing of the avian poxvirus 4b core protein produced an identical viral sequence from each of 20 great tits tested from Great Britain. This sequence was identical to that from great tits from central Europe and Scandinavia. In contrast, sequence variation was evident amongst virus tested from 17 non-Paridae hosts of 5 species. Our findings show Paridae pox to be an emerging infectious disease in wild birds in Great Britain, apparently originating from viral incursion from central Europe or Scandinavia.

Avian pox has a worldwide distribution, but prior to this investigation has not been reported in free-ranging flamingo populations. During observations of the first successful breeding of Lesser Flamingos on a purpose-built island, at Kamfers Dam near Kimberley, South Africa, multiple small, raised, crusted plaques on the legs and facial area were noticed on 30% of the fledgling flamingos. A diagnosis of avipoxvirus infection was made on the basis of the macroscopic, histologic, and electron microscopic features, and was further confirmed by DNA sequence analysis. The avipoxvirus detected was very similar to that previously detected in albatross and falcons.

Proliferative growth, consistent with poxvirus infection, encapsulated plastic beak-bits and covered the dorsal portion of the upper beak and nares of adult male and female captive-raised Hungarian partridges. Three representative birds were submitted to the Wisconsin Veterinary Diagnostic Laboratory for necropsy. Lesions in the necropsied birds extended through the nares, where the plastic bit ends are designed to rest. The lesions also variably extended caudally into the oropharynx and cranially within the beak epithelium, and included palate deformity and beak necrosis. Poxvirus was diagnosed in all of the birds examined based on histopathology, electron microscopy, and polymerase chain reaction amplification and sequencing. This report is the first to describe avian pox lesions associated with the application of beak-bits and the resulting beak and oral pathology.

The American crow (Corvus brachyrhynchos) is a common urban and rural inhabitant of the Northeast and Midwest United States that is commonly infected with West Nile virus (WNV). The current study was initiated to determine non-WNV-associated causes of mortality in the American crow. All animals (40/40) tested negative for WNV infection via polymerase chain reaction and had no evidence of infection based on immunohistochemistry. Common gross necropsy findings included external trauma (6/40), hepatosplenomegaly (6/40), poxviral dermatitis (5/40), and pneumonia (3/40). Common histologic findings included endoparasitism (32/40), multifocal hepatic and splenic necrosis (7/40), pigment accumulation in the spleen (5/40), and disseminated bacterial infection (3/40). The most significant and debilitating diseases included fungal pneumonia and poxvirus-associated lesions. The present report increases the knowledge of diseases present in the American crow population.

Fifteen strains of Avipoxvirus from different avian species were isolated and molecular biologically characterized. Most strains did not produce evident pocks on the chorioallantoic membranes of commercial and specific-pathogen free embryonated chicken eggs where, on the contrary, microscopic signs of viral growth were always detected. Polymerase chain reaction of highly conserved P4b gene was positive for all cases confirming to be a reliable diagnostic method for Avipoxvirus. Sequencing of these amplicons confirmed most strains clustered either with Fowlpox virus or with Canarypox virus whereas a possible new clade could be hypothesized for one strain from Japanese quail. Classification of Avipoxvirus strains by amplification of the newly identified locus fpv140 revealed major limitations as only five samples were positive. These results underline the importance to undertake similar studies on higher numbers of Avipoxvirus isolates and on wider genomic regions of this large viral group.

An adult female white-tailed sea eagle (Haliaeetus albicilla), over 12 years old, was found moribund and sent to the Wildlife Rescue Center in Kushiro, Japan. Grossly, the bird had multifocal yellow to black nodules in the beak, tongue, mucosa of the oral cavity, eyelids, and legs. Histologically, the cutaneous nodules revealed severe epidermal hyperplasia. The thickened epithelium, from prickle cell layer to horny layer, consisted of swollen keratinocytes containing frequent eosinophilic intra-cytoplasmic inclusions, Bollinger bodies. Ultrastructurally, the epidermal cells had cytoplasmic viral particles with characteristics of poxvirus. Furthermore, the 4b core gene sequence of an avian poxvirus was detected in a DNA sample prepared from the nodular lesions by polymerase chain reaction. The nucleotide sequence of the polymerase chain reaction product showed 78 to 95% similarities to the sequences of other avian poxviruses. Phylogenetic analysis showed that the sequence is clustered in clade A but distant from all the subclades previously reported. The results imply that it is a novel avian poxvirus. To our knowledge this is the first report of avian poxvirus infection in white-tailed sea eagles.

The present study was carried out to investigate the epidemiology and lesions of avian pox in captive peafowl chicks. Overall values of morbidity, mortality and case fatality were 45.2%, 27.1% and 60.0%, respectively. The chicks of 9 to 12 weeks of age showed a significantly (P<0.001) higher prevalence rate than other age groups. The morbidity and mortality due to avian pox in peafowl chicks was significantly (P<0.001) reduced when kept in mosquito-proof cages and hatched under broody chicken hens. Morbidity due to poxvirus infection on the peafowl farm was 82%, 26% and 12% in successive years. This reduction might have been the result of the introduction of mosquito-proof nets after year 1, although this was not the subject of a controlled experiment. All of the peafowl chicks suffering from dry pox showed pustular and nodular lesions on eye lids, beak, legs and toes. Distribution of lesions in different body parts varied significantly (P<0.023). Lesion diameters were less than 1 cm (59.73%), 1 to 2 cm (23.75%) and more than 2 cm (16.87%). Histopathological studies revealed extensive proliferation of subdermal connective tissue and infiltration of heterophils and macrophages. The keratinocytes showed degenerative changes in the form of cytoplasmic vacuolation, ballooning and hyper-chromatic nuclei. Eosinophilic intracytoplasmic inclusions (Bollinger bodies) in keratinocytes were consistently present. It was concluded that avian pox rendered high morbidity, mortality and case fatality in peafowl chicks.

The prevalence, cutaneous manifestations and concurrent clinical signs of avipoxvirus infection in 3706 falcons in two Middle Eastern countries are reported. Diagnosis was based on evidence of typical 'dry' skin lesions on featherless parts of the body and microscopic detection of Bollinger bodies in epithelial cells. Avipoxvirus was isolated from one representative case. Overall prevalence of cutaneous changes due to avipoxvirus infection did not differ significantly between Kuwait (2.7%) and Dubai (2.3%), although pox lesions were more prevalent on the feet of birds from Kuwait (67.4% vs. 50%) and more common on the eyelids of birds from Dubai (45.6% vs. 30.4%). Foot lesions were always present in birds with multiple infection sites. Some birds from Dubai had severe infection associated with weight loss, anorexia, lethargy, vomiting, central nervous system involvement and ultimately death.

We determined prevalence and altitudinal distribution of introduced avian malarial infections (Plasmodium relictum) and pox-like lesions (Avipoxvirus) in forest birds from Kipahulu Valley, Haleakalā National Park, on the island of Maui, and we identified primary larval habitat for the mosquito vector of this disease. This intensively managed wilderness area and scientific reserve is one of the most pristine areas of native forest remaining in the state of Hawai'i, and it will become increasingly important as a site for restoration and recovery of endangered forest birds. Overall prevalence of malarial infections in the valley was 8% (11/133) in native species and 4% (4/101) in nonnative passerines; prevalence was lower than reported for comparable elevations and habitats elsewhere in the state. Infections occurred primarily in 'Apapane (Himatione sanguinea) and Hawai'i 'Amakihi (Hemignathus virens) at elevations below 1,400 m. Pox-like lesions were detected in only two Hawai'i 'Amakihi (2%; 2/94) at elevations below 950 m. We did not detect malaria or pox in birds caught at 1,400 m in upper reaches of the valley. Adult mosquitoes (Culex quinquefasciatus) were captured at four sites at elevations of 640, 760, 915, and 975 m, respectively. Culex quinquefasciatus larvae were found only in rock holes along intermittent tributaries of the two largest streams in the valley, but not in standing surface water, pig wallows, ground pools, tree cavities, and tree fern cavities. Mosquito populations in the valley are low, and they are probably influenced by periods of high rainfall that flush stream systems.

Six common buzzards from a bird rescue centre showed wart-like lesions on their toes. The lesions consisted of multiple crusty and proliferative nodules surrounded by skin swelling. Histologically, epithelial cell hypertrophy and hyperplasia with ballooning degeneration and large intracytoplasmic inclusion bodies consistent with avipoxvirus infection were seen. The virus was isolated in embryonated chicken eggs. Positive chorioallantoic membranes and samples of skin lesions were submitted for polymerase chain reaction. Molecular characterization based on the 4b core protein indicates a 100% homology of the isolated poxvirus with avian poxviruses belonging to subclade A2. However, analysis of fpv139 locus does not reveal similarities of the isolate with other avian poxviruses.

An adult mourning dove (Zenaidura macroura) was presented with dyspnea, poor body condition, and poor flight endurance. Nodular lesions were visible on the cere, both feet, and skin covering the pectoral region. Histopathological examination revealed epithelial hyperplasia with eosinophilic intracytoplasmic inclusion bodies consistent with Avipoxvirus infection.

Pox lesions involving feathered and unfeathered skin, the oral cavity and the uropygial gland were found in Chinese jungle mynahs. Characteristic intracytoplasmic inclusions were detected in the proliferative cells of all lesions. Ultrastructurally, the virus particles consisted of a convoluted outer membrane enclosing lateral bodies and a biconcave central core, typical for poxvirus. The nucleotide sequences of the amplicon obtained with a set of primers for the 4b core protein of fowl poxvirus revealed that the mynah poxvirus was phylogenetically related to wood pigeon poxvirus. This is the first report of poxvirus infection affecting the uropygial gland.

An adult American crow (Corvus brachyrhynchos) from Virginia, USA, was diagnosed with combined infection of avian poxvirus and the skin fluke Collyriclum faba. The flukes and viral inclusions were combined in a large (4 x 4 cm) multilobulated proliferative mass on the ventrum just cranial to the cloaca. The flukes were identified using light microscopy of organisms obtained by antemortem wedge biopsy. Intraepithelial cytoplasmic inclusions consistent with poxvirus infection were seen on histopathologic examination of the mass.

Between January 2002 and November 2003, 50% (n = 395) of short-toed larks (Calandrella rufescens) and 28% (n = 139) of Berthelot's pipits (Anthus berthelotti) examined on the islands of Fuerteventura and Lanzarote, Canary Islands, had gross lesions compatible with avian pox. However, Spanish sparrows (Passer hispaniolensis, n = 128) and trumpeter finches (Bucanetes githagineus, n = 228), which inhabit the same steppe habitats associated with goat husbandry, did not have poxlike lesions. Histopathology and electron microscopy confirmed poxvirus in the lesions, whereas serology using standard, fowl poxvirus-and pigeon poxvirus-based diagnostic agar gel immunodiffusion techniques was negative, likely because of the limited (74.6% pipit; 74.9% lark) similarity between the viruses in our species and fowlpox virus on which the serologic tests rely. On the basis of polymerase chain reaction analyses, the virus isolated from dried lesions of C. rufescens has 80.5% similarity with the virus isolated from A. berthelotti and 91.3% similarity with canarypox, whereas A. berthelotti poxvirus has only 80% similarity with canarypox. We have two distinct and possibly new avian poxviruses. Both poultry and the wild birds on the farms were heavily infested by fleas, which may have acted as vectors in transmission of poxvirus. Disease prevalence in these Canary Island passerines is higher than that described in song birds in Hawaii that are now threatened, endangered, or extinct. Environmental and biological factors contributing to increased disease susceptibility of these isolated populations must be investigated.

Two diseased young white-tailed laurel-pigeons (Columba junoniae), an endemic and endangered species of the Canary Islands (Spain), were found in La Palma. They were very depressed and had severe cutaneous yellowish nodular lesions in feathered and unfeathered areas on the bodies of both birds. Necropsy and histopathologic analyses were conducted. The presence of epidermal hypertrophy and hyperplasia in cutaneous lesions, as well as several acidophilic intracytoplasmic inclusions in affected epithelial cells (Bollinger bodies), confirmed avian poxvirus infection. This is the first report of avian pox in whitetailed laurel-pigeons or in any other free-ranging bird in the Canaries, and it might indicate that other threatened birds of the Canarian Archipelago may be affected by this viral disease.

Avipoxviruses from different geographic regions of the world have been characterized to study their genetic and biological properties, but so far, no such work has been performed on Norwegian isolates. Lesions suggestive of avian pox, found on a Norwegian wild sparrow (Passer domesticus) and wood pigeon (Palumbus palumbus), were obtained in 1972 and 1996, respectively. Histologically, these lesions were demonstrated to be characteristic of poxvirus infections and the poxvirus was observed using an electron microscope. The resulting viruses were propagated in chicken embryo fibroblast cells. Restriction fragment length polymorphism of genomes from 2 Norwegian isolates and fowl pox vaccine strain, generated by BamHI, revealed a high degree of heterogeneity among the isolates. The profiles of avipoxviruses isolated from wild birds were clearly distinct from each other and also to the fowl poxvirus strain. Furthermore, chickens experimentally infected with pigeon poxvirus had higher antibody titers and extensive lesions compared to other isolates. This may suggest that pigeon poxvirus is more virulent than the other isolates.

Members of a wild-caught colony of 16 gray-crowned rosy finches (Leucosticte tephrocotis) were presented with dermal and mucosal lesions, anorexia, emaciation, lethargy, and sudden death. Lesions included dermatitis, conjunctivitis, and glossitis. Skin scrapings from and bacterial culture of dermal lesions yielded Staphylococcus aureus and Candida albicans. Necropsy and histologic examination revealed characteristic epidermal and mucosal pox lesions, with the presence of characteristic Bollinger body intracellular inclusions. Electron microscopy (EM) provided confirmation of pox virus infection. This epornitic resulted in the death or euthanasia of 12 birds (75% morbidity and associated mortality) and was brought to conclusion through culling of affected birds. The source of infection remains unknown, although multiple modes of introduction exist. Similar epornitics may be prevented through indoor, species-specific housing, and quarantine. Vaccination and antiparasitic treatment may reduce the risk of disease spread.

The diagnosis and pathology of an avian pox outbreak in free-living red-legged partridges in Cádiz, Southern Spain, is described. Diagnosis of the disease was based on histopathology, ultrastructural examination of, and virus isolation from lesions of necropsied animals. Lesions were present mainly in juvenile partridges (41%), and were observed primarily on the dorsal part of the digits or on the hock joint. The lesions ranged from small wartlike nodules to large tumor-like lesions. The presence of acute lesions of any grade as opposed to absence of lesions or healed lesions adversely affected body condition of the partridges (P <.01). Further investigations on the epidemiology of the disease and on the relation of the isolated strains to other avian poxviruses are under way.

Avian poxvirus was isolated from nodules on the heads and conjunctiva of two 3-to-4-wk-old ostrich chicks. The ostriches from which poxvirus was isolated had been placed on premises where turkeys that had shown evidence of poxvirus infection had been raised earlier. Microscopically, the nodules from the ostriches were composed of proliferating and hypertrophic epithelial cells that formed large fronds. Most of the hypertrophic epithelial cells contained large eosinophilic intracytoplasmic inclusion bodies characteristic of poxvirus. Characterization of the avian poxvirus isolated from the cutaneous lesions in ostriches was based on western blotting of virus antigen, restriction fragment length polymorphism of genomic DNA, pathogenesis, and cross-protection studies in chickens. Antigenic and genetic studies did not reveal any significant difference between the poxvirus isolated from ostriches (PVO) and fowl poxvirus (FPV). Further, susceptible chickens immunized with the PVO were protected when challenged with a virulent strain of FPV. Thus, the poxvirus isolated from ostriches had similar antigenic, genetic, and biological properties to FPV.

Asian pox was diagnosed in three sanderlings (Calidris alba) on Sanibel Island, Florida (USA) in February 1997. All three cases had large tumor-like lesions which contributed significantly to their mortality. Poxvirus infection was confirmed by cytology, histopathology, and electron microscopy. This is the first report of poxvirus infection in sanderlings.

During the spring of 1995, 1996 and 1997 following tests on six peregrine falcons (Falco peregrinus) and two gyr falcons (Falco rusticolus), Salmonella typhimurium was isolated from liver, spleen and small intestines. Four of the falcons (two peregrines and two gyrs) had also contracted Chlamydia infection, three peregrines a pox infection and one peregrine a Herpesvirus infection. It is believed that this dual infection was fatal for these birds. The disease was marked by anorexia, dehydration and green-coloured droppings. Necropsy of all falcons revealed discolouration of the liver and enlargement of liver and spleen. Miliary necrosis was detected in all livers. A total of 12 salmonella serovars, including S. typhimurium, were cultured from faeces of 48 falcons which showed no clinical signs.

Avian pox was diagnosed in two eastern screech owls (Otus asio) and two barred owls (Strix, varia) living in different regions of Florida (USA) between November 1994 and October 1995. Avian poxvirus infection was confirmed by the presence of eosinophilic intracytoplasmic epidermal inclusions (Bollinger bodies) on light microscopy of tissue from all four owls. Additionally, typical poxvirus particles were demonstrated by electron microscopy of a lesion from one of the eastern screech owls. These are the first published case reports of avian pox in eastern screech owls and barred owls.

Natural pox infection occurred in a free-living rough-legged hawk (Buteo lagopus) in northeastern North Dakota. Gross, histological and electron microscopic findings were typical of pox infection, and characteristic lesions developed in red-tailed hawks (Buteo jamaicensis) but not in great horned owls (Bubo virginianus) following inoculation with case material. Death of the rough-legged hawk was attributed to starvation rsulting from inability to capture prey and to blood loss from foot lesions.

Prevalences of poxvirus-like lesions were determined for 177 northern bobwhites (Colinus virginianus) and 24 scaled quail (Callipepla squamata) trapped in southern Texas from 1976 to 1979 and for 190 northern bobwhites and 105 scaled quail shot at five locations in southern Texas from 1980 to 1981. None of the northern bobwhites trapped in 1976-1977 was infected, but 54% of the trapped scaled quail were infected; 17% of the northern bobwhites and 34% of the scaled quail shot in 1980-1981 had pox lesions, primarily on the wings. Prevalence was unrelated to sex or age of birds. For both species, prevalence was greatest during late spring and early summer. Histologic and electron microscopic examination confirmed poxvirus in two scaled quail, which constituted the first report of poxvirus in this species.

In an aviary housing 200 six-month-old canaries, 165 became ill and 145 died over a 6-week period from a disease initially characterized by lethargy, ruffled feathers, open-mouth breathing, and death in 2 to 3 days. Proliferative "pox-like" lesions around the eyes and mouth were not seen until the 4th week. At necropsy, initially affected birds had cloudy air sacs and patchy pneumonia. Histologically, the lungs had proliferative necrotizing bronchitis. Birds necropsied later had proliferative skin lesions and intracytoplasmic inclusions typical of poxvirus in the epidermis and airway epithelium. A virus was isolated from an organ pool of lung, air sac, liver, and skin of affected birds and was identified by electron microscopy as poxvirus.

Lesions, grossly and histologically typical of pox infection, occurred in a white-backed magpie from Melbourne, Australia. Electron microscopic examination revealed typical poxvirus particles in lesion material. The disease was experimentally transmitted to other magpies, but chickens, turkeys, pigeons, and canaries were refractory to experimental infection with magpie poxvirus. The epidemiology of magpie pox and the probable occurrence of pox-like disease in other native Australian birds are discussed.