Systemic avian poxvirus infections associated with the B1 subclade of canarypox virus.

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.

Snapshot of the Phylogenetic Relationships among Avian Poxviruses Circulating in Portugal between 2017 and 2023.

Avipoxvirus (APV), a linear dsDNA virus belonging to the subfamily Chordopoxvirinae of the family Poxviridae, infects more than 278 species of domestic and wild birds. It is responsible for causing avian pox disease, characterized by its cutaneous and diphtheric forms. With a high transmission capacity, it can cause high economic losses and damage to the ecosystem. Several diagnostic methods are available, and bird vaccination can be an effective preventive measure. Ten APV-positive samples were analyzed to update the molecular characterization and phylogenetic analysis of viruses isolated in Portugal between 2017 and 2023. A P4b gene fragment was amplified using a PCR, and the nucleotide sequence of the amplicons was determined using Sanger sequencing. The sequences obtained were aligned using ClustalW, and a maximum likelihood phylogenetic tree was constructed. With this study, it was possible to verify that the analyzed sequences are distributed in subclades A1, A2, B1, and B3. Since some of them are quite similar to others from different countries and obtained in different years, it is possible to conclude that there have been several viral introductions in Portugal. Finally, it was possible to successfully update the data on Avipoxviruses in Portugal.

Genomic characteristics of an avipoxvirus 282E4 strain.

Avipoxvirus 282E4 strain was extensively applied into recombinant vaccine vector to prevent other infectious diseases. However, little information on the genomic background, functional and genetic evolutionary of the isolate 282E4 strain was clarified. The results showed that the linear genome of avipoxvirus 282E4 was 308,826 bp, containing 313 open reading frames (ORFs) and 12 new predicted ORFs. The 282E4 strain appears to encode two novel thymidine kinase proteins and two TGF-beta-like proteins that may be associated with the suppression of the host's antiviral response. Avipoxvirus 282E4 also encodes 57 ankyrin repeat proteins and 5 variola B22R-like proteins, which composed 7% of the avipoxvirus 282E4 genome. GO and KEGG analysis further revealed that 12 ORFs participate in viral transcription process, 7 ORFs may function during DNA repair, replication and biological synthesis, and ORF 208 is involved in the process of virus life cycle. Interestingly, phylogenetic analysis based on concatenated sequences p4b and DNA polymerase of avipoxviruses gene demonstrates that avipoxvirus 282E4 strain is divergent from known FWPV isolates and is similar to shearwater poxvirus (SWPV-1) that belongs to the CNPV-like virus. Sequencing avipoxvirus 282E4 is a significant step to judge the genetic position of avipoxviruses within the larger Poxviridae phylogenetic tree and provide a new insight into the genetic background of avipoxvirus 282E4 and interspecies transmission of poxviruses, meanwhile, explanation of gene function provides theoretical foundation for vaccine design with 282E4 strain as skeleton.

A novel pathogenic avipoxvirus infecting oriental turtle dove (Streptopelia orientalis) in China shows a high genomic and evolutionary proximity with the pigeon avipoxviruses isolated globally.

Avipoxviruses are considered as significant viral pathogen infecting a wide range of domestic and wild bird species globally, yet the majority of avipoxviruses that infect the wild bird species remain uncharacterized and their genetic diversities remain unclear. In this study, we present a novel pathogenic avipoxvirus isolated from the cutaneous pox lesions of a wild oriental turtle dove (Streptopelia orientalis), tentatively named as turtle dovepox virus (TDPV). The avipoxvirus was isolated by using the chorioallantoic membranes of specific pathogen-free chicken embryos which showed characteristic focal pock lesions, followed by cytopathic effects in host cells infected with oriental turtle dovepox virus. An effort in sequencing the whole genome of the poxvirus using next-generation sequencing was given, and the first whole genome sequence of TDPV was obtained. The TDPV genome was 281,386 bp in length and contained 380 predicted open reading frames (ORFs). While 336 of the predicted ORFs showed homology to other characterized avipoxviruses, the other 44 ORFs were unique. Subsequent phylogenetic analyses showed that the novel TDPV shared the closest genetic evolutionary linkage with the avipoxviruses isolated from pigeon in South Africa and India, of which the TDPV genome had the highest sequence similarity (92.5%) with South African pigeonpox virus (FeP2). In conclusion, the sequenced TDPV is significantly different from any other avipoxviruses isolated from avian or other natural host species considering genomic architecture and observed sequence similarity index. Thus, it likely should be considered a separate species. IMPORTANCE Over the past few decades, avipoxviruses have been found in a number of wild bird species including the oriental turtle dove. However, there is no whole genome sequence information on avipoxviruses isolated from oriental turtle dove, leaving us unclear about the evolutionary linkage of avipoxviruses in oriental turtle dove and other wild bird species. Thus, we believe that our study makes a significant contribution because it is the first report of the whole genome sequence of TDPV isolated from a wild oriental turtle dove, which enriches the genomic information of the genus Avipoxvirus, furthermore, contributes to tracking the genetic evolution of avipoxviruses-infected oriental turtle dove species.

Vertebrate-tropism of a cressdnavirus lineage implicated by poxvirus gene capture.

Among cressdnaviruses, only the family Circoviridae is recognized to infect vertebrates, while many others have unknown hosts. Detection of virus-to-host horizontal gene transfer is useful for solving such virus-host relationships. Here, we extend this utility to an unusual case of virus-to-virus horizontal transfer, showing multiple ancient captures of cressdnavirus Rep genes by avipoxviruses-large dsDNA pathogens of birds and other saurians. As gene transfers must have occurred during virus coinfections, saurian hosts were implied for the cressdnavirus donor lineage. Surprisingly, phylogenetic analysis revealed that donors were not members of the vertebrate-infecting Circoviridae, instead belonging to a previously unclassified family that we name Draupnirviridae. While draupnirviruses still circulate today, we show that those in the genus Krikovirus infected saurian vertebrates at least 114 Mya, leaving endogenous viral elements inside snake, lizard, and turtle genomes throughout the Cretaceous Period. Endogenous krikovirus elements in some insect genomes and frequent detection in mosquitoes imply that spillover to vertebrates was arthropod mediated, while ancestral draupnirviruses likely infected protists before their emergence in animals. A modern krikovirus sampled from an avipoxvirus-induced lesion shows that their interaction with poxviruses is ongoing. Captured Rep genes in poxvirus genomes often have inactivated catalytic motifs, yet near-total presence across the Avipoxvirus genus, and evidence of both expression and purifying selection on them suggests currently unknown functions.

A Novel Pathogenic Avipoxvirus Infecting Vulnerable Cook's Petrel (Pterodroma cookii) in Australia Demonstrates a High Genomic and Evolutionary Proximity with South African Avipoxviruses.

Avipoxviruses are assumed to be restricted to avian hosts and are considered to be important viral pathogens that may impact the conservation of many vulnerable or endangered birds. Recent reports of avipoxvirus-like viruses from reptiles suggest that cross-species transmission may be possible within birds and other species. Most of the avipoxviruses in wild and sea birds remain uncharacterized, and their genetic variability is unclear. Here, cutaneous pox lesions were used to recover a novel, full-length Cook's petrelpox virus (CPPV) genome from a vulnerable Cook's petrel (Pterodroma cookii), and this was followed by the detection of immature virions using transmission electron microscopy (TEM). The CPPV genome was 314,065 bp in length and contained 357 predicted open-reading frames (ORFs). While 323 of the ORFs of the CPPV genome had the greatest similarity with the gene products of other avipoxviruses, a further 34 ORFs were novel. Subsequent phylogenetic analyses showed that the CPPV was most closely related to other avipoxviruses that were isolated mostly from South African bird species and demonstrated the highest sequence similarity with a recently isolated flamingopox virus (88.9%) in South Africa. Considering the sequence similarity observed between CPPV and other avipoxviruses, TEM evidence of poxvirus particles, and phylogenetic position, this study concluded that CPPV is a distinct candidate of avipoxviruses. IMPORTANCE Emerging viral disease is a significant concern with potential consequences for human, animal, and environmental health. Over the past several decades, multiple novel viruses have been found in wildlife species, including birds, and they can pose a threat to vulnerable and endangered species. Cook's petrel is currently listed as vulnerable. The threats to the species vary, but are, to a large degree, due to anthropogenic impacts, such as climate change, habitat loss, pollution, and other disturbances by humans. Knowledge of viral pathogens, including poxvirus of Cook's petrel is currently virtually nonexistent.

Unexpected Pathogen Diversity Detected in Australian Avifauna Highlights Potential Biosecurity Challenges.

Birds may act as hosts for numerous pathogens, including members of the family Chlamydiaceae, beak and feather disease virus (BFDV), avipoxviruses, Columbid alphaherpesvirus 1 (CoAHV1) and Psittacid alphaherpesvirus 1 (PsAHV1), all of which are a significant biosecurity concern in Australia. While Chlamydiaceae and BFDV have previously been detected in Australian avian taxa, the prevalence and host range of avipoxviruses, CoAHV1 and PsAHV1 in Australian birds remain undetermined. To better understand the occurrence of these pathogens, we screened 486 wild birds (kingfisher, parrot, pigeon and raptor species) presented to two wildlife hospitals between May 2019 and December 2021. Utilising various qPCR assays, we detected PsAHV1 for the first time in wild Australian birds (37/486; 7.61%), in addition to BFDV (163/468; 33.54%), Chlamydiaceae (98/468; 20.16%), avipoxviruses (46/486; 9.47%) and CoAHV1 (43/486; 8.85%). Phylogenetic analysis revealed that BFDV sequences detected from birds in this study cluster within two predominant superclades, infecting both psittacine and non-psittacine species. However, BFDV disease manifestation was only observed in psittacine species. All Avipoxvirus sequences clustered together and were identical to other global reference strains. Similarly, PsAHV1 sequences from this study were detected from a series of novel hosts (apart from psittacine species) and identical to sequences detected from Brazilian psittacine species, raising significant biosecurity concerns, particularly for endangered parrot recovery programs. Overall, these results highlight the high pathogen diversity in wild Australian birds, the ecology of these pathogens in potential natural reservoirs, and the spillover potential of these pathogens into novel host species in which these agents cause disease.

Intralesional application of ribavirin in two American flamingos (Phoenicopterus ruber) with poxvirus infection.

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.

Genome-wide identification and characterization of microsatellite markers within the Avipoxviruses.

Microsatellite markers or Simple Sequence Repeats (SSRs) are gaining importance for molecular characterization of the virus as well as estimation of evolution patterns due to its high-polymorphic nature. The Avipoxvirus is the causative agent of pox-like lesions in more than 300 birds and one of the major diseases for the extinction of endangered avian species. Therefore, we conducted a genome-wide analysis to decipher the type, distribution pattern of 14 complete genomes derived from the Avipoxvirus genus. The in-silico screening deciphered the existence of 917-2632 SSRs per strain. In the case of compound SSRs (cSSRs), the value was obtained 44-255 per genome. Our analysis indicates that the di-nucleotide repeats (52.74%) are the most abundant, followed by the mononucleotides (34.79), trinucleotides (11.57%), tetranucleotides (0.64%), pentanucleotides (0.12%) and hexanucleotides (0.15%) repeats. The specific parameters like Relative Abundance (RA) and Relative Density (RD) of microsatellites ranged within 5.5-8.12 and 33.08-53.58 bp/kb. The analysis of RA and RD value of compound microsatellites resulted between 0.25-0.82 and 4.64-15.12 bp/kb. The analysis of motif composition of cSSR revealed that most of the compound microsatellites were made up of two microsatellites, with some unique duplicated pattern of the motif like, (TA)-x-(TA), (TCA)-x-(TCA), etc. and self-complementary motifs, such as (TA)-x-(AT). Finally, we validated forty sets of compound microsatellite markers through an in-vitro approach utilizing clinical specimens and mapping the sequencing products with the database through comparative genomics approaches. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03169-4.

Outbreaks of Avipoxvirus Clade E in Vaccinated Broiler Breeders with Exacerbated Beak Injuries and Sex Differences in Severity.

Avipoxvirus affects chickens and wild birds, and it is characterized by lesions on the nonfeathered parts of the body (the cutaneous form), or necrotic lesions in the upper respiratory tract (the diphtheritic form). In poultry farming, avian pox is usually controlled by live attenuated vaccines. However, there have been many reports of outbreaks, even in flocks of vaccinated birds. In the present study, different outbreaks of the emerging clade E avipoxvirus were detected in commercial breeder flocks of chickens vaccinated against fowlpox virus in Southeast Brazil. Clinical manifestations of these outbreaks included a marked prevalence of moderate to severe progressive lesions in the beaks of affected birds, especially in roosters with increased mortality (up to 8.48%). Also, a reduced hatchability (up to 20.77% fewer hatching eggs) was observed in these flocks. Analysis of clinical samples through light and transmission electron microscopy revealed the presence of Bollinger bodies and poxvirus particles in epithelial cells and affecting chondrocytes. PCR, sequencing, and phylogenetic analysis of major core protein (P4b) and DNA polymerase (pol) genes identified this virus as clade E avipoxvirus. We also developed qPCR assays for open reading frames (ORFs) 49, 114, and 159 to detect and quantify this emergent virus. These results show the arrival and initial spread of this pathogen in the poultry industry, which was associated with harmful outbreaks and exacerbated clinical manifestations in vaccinated commercial breeder flocks. This study also highlights the relevance of permanent vigilance and the need to improve sanitary and vaccination programs.

Poxvirus infection in house finches (Haemorhous mexicanus): Genome sequence analysis and patterns of infection in wild birds.

Poxviruses (family: Poxviridae) infect many avian species, causing several disease outcomes, the most common of which are proliferative lesions on the legs, feet, and/or head. Few avian studies of poxvirus to date have combined molecular and ecological analyses to obtain a more comprehensive understanding of the identity and distribution of the disease in a population. Here, we describe patterns of poxvirus infection in an urban population of house finches (Haemorhous mexicanus) in Arizona (USA) and use high-throughput sequencing to determine the genome sequence of the virus. We found that poxvirus prevalence, based on visual identification of pox lesions, was 7.2% (17 infected birds out of a total of 235 sampled) in our population during summer 2021. Disease severity was low; 14 of the 17 infected birds had a single small lesion on the skin overlaying the eye, leg, and ear canal. All but two lesions were found on the feet; one bird had a lesion on the eye and the other in the ear opening. We also investigated possible temporal (i.e., date of capture) and biological correlates (e.g., age, sex, body condition, degree of infection with coccidian endoparasites) of poxvirus infection in urban-caught house finches during this time but found that none of these significantly correlated with poxvirus presence/absence. Two complete poxvirus genomes were determined from two infected birds. These genomes are ∼354,000 bp and share 99.7% similarity with each other, and 82% with a canarypox virus genome, the most closely related avipoxvirus. This novel finchpox virus is the first to be reported in house finches and has a similar genome organization to other avipoxviruses.

Molecular characterization of avipoxviruses circulating in Windhoek district, Namibia 2021.

Samples from eleven birds (chicken, dove and peacock) with symptoms of fowlpox, caused by the avipoxvirus (APV), were collected in seven different areas of the Windhoek district, Namibia between April and October 2021. A fragment of the 4b core protein and the DNA polymerase gene of APV were amplified by PCR from the DNA of the samples and sequenced. Phylogenetic analysis revealed that the viruses present in the chickens all belonged to clade A1 while the viruses in the doves and peacock were from subclade A3.1. This is the first report of subclade A3.1 avipoxvirus in peacock. In addition, all of the samples obtained from chickens were shown by PCR to be positive for the integration of reticuloendotheliosis virus while those from the doves and peacocks were negative. This study is the first characterization of avipoxvirus in Namibia and provides additional information on the presence of avipoxvirus in southern Africa.

Molecular Detection of Avipoxvirus in Wild Birds in Central Italy.

Avipoxviruses (APVs) are important pathogens of both domestic and wild birds. The associated disease is characterized by skin proliferative lesions in the cutaneous form or by lesions of the first digestive and respiratory tracts in the diphtheritic form. Previous studies investigated these infections in symptomatic wild birds worldwide, including Italy, but data about the circulation of APVs in healthy avian wildlife are not available. The present study tested spleen samples from 300 wild birds without typical lesions to detect Avipoxvirus DNA. Overall, 43.33% of the samples scored positive. Aquatic birds were more frequently infected (55.42%) than other animals (26.40%), and in Anseriformes, high positivity was found (52.87%). The obtained results suggest that wild birds could be asymptomatic carriers of Avipoxviruses, opening new possible epidemiological scenarios.

Evidence of a Possible Viral Host Switch Event in an Avipoxvirus Isolated from an Endangered Northern Royal Albatross (Diomedea sanfordi).

Avipoxviruses have been characterized from many avian species. Two recent studies have reported avipoxvirus-like viruses with varying pathogenicity in reptiles. Avipoxviruses are considered to be restricted to avian hosts. However, reports of avipoxvirus-like viruses from reptiles such as the green sea turtle (Chelonia mydas) and crocodile tegu (Crocodilurus amazonicus) suggest that cross-species transmission, within avian species and beyond, may be possible. Here we report evidence for a possible host switching event with a fowlpox-like virus recovered from an endangered northern royal albatross (Diomodea sanfordi)-a species of Procellariiformes, unrelated to Galliformes, not previously known to have been infected with fowlpox-like viruses. Complete genome sequencing of this virus, tentatively designated albatrosspox virus 2 (ALPV2), contained many fowlpox virus-like genes, but also 63 unique genes that are not reported in any other poxvirus. The ALPV2 genome contained 296 predicted genes homologous to different avipoxviruses, 260 of which were homologous to an American strain of fowlpox virus (FWPV). Subsequent phylogenetic analyses indicate that ALPV2 likely originated from a fowlpox virus-like progenitor. These findings highlight the importance of host-switching events where viruses cross species barriers with the risk of disease in close and distantly related host populations.

Genomic characterisation of a novel avipoxvirus, magpiepox virus 2, from an Australian magpie (Gymnorhina tibicen terraereginae).

Avipoxviruses are large, double-stranded DNA viruses and are considered significant pathogens that may impact on the conservation of numerous bird species. The vast majority of avipoxviruses in wild birds remain uncharacterised and their genetic variability is unclear. Here, we fully sequenced a novel avipoxvirus, magpiepox virus 2 (MPPV2), which was isolated 62 years ago (in 1956) from an Australian black-backed magpie. The MPPV2 genome was 298,392 bp in length and contained 419 predicted open-reading frames (ORFs). While 43 ORFs were novel, a further 24 ORFs were absent compared with another magpiepox virus (MPPV) characterised in 2018. The MPPV2 genome contained an additional ten genes that were homologs to shearwaterpox virus 2 (SWPV2). Subsequent phylogenetic analyses showed that the novel MPPV2 was most closely related to other avipoxviruses isolated from passerine and shearwater bird species, and demonstrated a high degree of sequence similarity (95.0%) with MPPV.

Genomic Characterisation of a Novel Avipoxvirus Isolated from an Endangered Northern Royal Albatross (Diomedea sanfordi).

Marine bird populations have been declining globally with the factors driving this decline not fully understood. Viral diseases, including those caused by poxviruses, are a concern for endangered seabird species. In this study we have characterised a novel avipoxvirus, tentatively designated albatrosspox virus (ALPV), isolated from a skin lesion of an endangered New Zealand northern royal albatross (Diomedea sanfordi). The ALPV genome was 351.9 kbp in length and contained 336 predicted genes, seven of which were determined to be unique. The highest number of genes (313) in the ALPV genome were homologs of those in shearwaterpox virus 2 (SWPV2), while a further 10 were homologs to canarypox virus (CNPV) and an additional six to shearwaterpox virus 1 (SWPV1). Phylogenetic analyses positioned the ALPV genome within a distinct subclade comprising recently isolated avipoxvirus genome sequences from shearwater, penguin and passerine bird species. This is the first reported genome sequence of ALPV from a northern royal albatross and will help to track the evolution of avipoxvirus infections in this endangered species.

Genomic Characterisation of a Novel Avipoxvirus Isolated from an Endangered Yellow-Eyed Penguin (Megadyptes antipodes).

Emerging viral diseases have become a significant concern due to their potential consequences for animal and environmental health. Over the past few decades, it has become clear that viruses emerging in wildlife may pose a major threat to vulnerable or endangered species. Diphtheritic stomatitis, likely to be caused by an avipoxvirus, has been recognised as a significant cause of mortality for the endangered yellow-eyed penguin (Megadyptes antipodes) in New Zealand. However, the avipoxvirus that infects yellow-eyed penguins has remained uncharacterised. Here, we report the complete genome of a novel avipoxvirus, penguinpox virus 2 (PEPV2), which was derived from a virus isolate obtained from a skin lesion of a yellow-eyed penguin. The PEPV2 genome is 349.8 kbp in length and contains 327 predicted genes; five of these genes were found to be unique, while a further two genes were absent compared to shearwaterpox virus 2 (SWPV2). In comparison with penguinpox virus (PEPV) isolated from an African penguin, there was a lack of conservation within the central region of the genome. Subsequent phylogenetic analyses of the PEPV2 genome positioned it within a distinct subclade comprising the recently isolated avipoxvirus genome sequences from shearwater, canary, and magpie bird species, and demonstrated a high degree of sequence similarity with SWPV2 (96.27%). This is the first reported genome sequence of PEPV2 from a yellow-eyed penguin and will help to track the evolution of avipoxvirus infections in this rare and endangered species.

Molecular characterisation of a novel pathogenic avipoxvirus from an Australian passerine bird, mudlark (Grallina cyanoleuca).

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%).

Avian disease surveillance on the island of San Cristóbal, Galápagos.

Endemic island species face unprecedented threats, with many populations in decline or at risk of extinction. One important threat is the introduction of novel and potentially devastating diseases, made more pressing due to accelerating global connectivity, urban development, and climatic changes. In the Galápagos archipelago two important wildlife diseases: avian pox (Avipoxvirus spp.) and avian malaria (Plasmodium spp. and related Haemosporidia) challenge endemic species. San Cristóbal island has seen a paucity of disease surveillance in avian populations, despite the island's connectedness to the continent and the wider archipelago. To survey prevalence and better understand the dynamics of these two diseases on San Cristóbal, we captured 1205 birds of 11 species on the island between 2016 and 2020. Study sites included urban and rural lowland localities as well as rural highland sites in 2019. Of 995 blood samples screened for avian haemosporidia, none tested positive for infection. In contrast, evidence of past and active pox infection was observed in 97 birds and identified as strains Gal1 and Gal2. Active pox prevalence differed significantly with contemporary climatic conditions, being highest during El Niño events (~11% in 2016 and in 2019 versus <1% in the La Niña year of 2018). Pox prevalence was also higher at urban sites than rural (11% to 4%, in 2019) and prevalence varied between host species, ranging from 12% in medium ground finches (Geospiza fortis) to 4% in Yellow Warblers (Setophaga petechial aureola). In the most common infected species (Small Ground Finch: Geospiza fuliginosa), birds recovered from pox had significantly longer wings, which may suggest a selective cost to infection. These results illustrate the threat future climate changes and urbanization may present in influencing disease dynamics in the Galápagos, while also highlighting unknowns regarding species-specific susceptibilities to avian pox and the transmission dynamics facilitating outbreaks within these iconic species.

Avipoxvirus detected in tumor-like lesions in a white-faced whistling duck (Dendrocygna viduata) / Avipoxvirus detectado em lesões tipo tumorais em uma marreca-irerê (Dendrocygna viduata)

Avipoxvirus is the etiological agent of the avian pox, a well-known disease of captive and wild birds, and it has been associated with tumor-like lesions in some avian species. A white-faced whistling duck (Dendrocygna viduata) raised in captivity was referred to a Veterinary Teaching Hospital in Northeast due to cutaneous nodules present in both wings. A few days after the clinical examination, the animal died naturally. Once submitted to necropsy, histopathological evaluation of the lesions revealed clusters of proliferating epithelial cells expanding toward the dermis. Some of these cells had round, well-defined, intracytoplasmic eosinophilic material suggestive of poxvirus inclusion (Bollinger bodies). PCR performed on the DNA extracted from tissue samples amplified a fragment of the 4b core protein gene (fpv167), which was purified and sequenced. This fragment of Avipoxvirus DNA present in these tumor-like lesions showed high genetic homology (100.0%) with other poxviruses detected in different avian species in several countries, but none of them were related to tumor-like lesions or squamous cell carcinoma. This is the first report of Avipoxvirus detected in tumor-like lesions of a white-faced whistling duck with phylogenetic analysis of the virus.(AU)

Avipoxvirus é o agente etiológico da varíola (bouba) aviária, uma doença bem descrita em aves de cativeiro e selvagens, tendo sido associada a lesões semelhantes a tumores em algumas dessas espécies. Uma marreca piadeira (Dendrocygna viduata), criada em cativeiro, foi atendida em um Hospital Veterinário na região nordeste devido à presença de nódulos cutâneos em ambas as asas. Alguns dias após o exame clínico, o animal veio a óbito naturalmente. A ave foi submetida à necropsia e coletados fragmentos das lesões para análise histopatológica, que revelou proliferação de células epiteliais expandindo para a derme. Algumas dessas células possuíam material eosinofílico intracitoplasmático e bem definido, sugestivo de inclusão de poxvírus (corpúsculos de Bollinger). A PCR realizada a partir do DNA extraído de amostras das lesões amplificou um fragmento do gene da proteína do núcleo 4b (fpv 167), que foi purificado e sequenciado. Esse fragmento de DNA de Avipoxvirus presente nas lesões relevou alta homologia genética (100,0%) com outros poxvírus detectados em diferentes espécies de aves em vários países, mas nenhum deles estava relacionado a lesões tumorais ou carcinoma espinocelular. Este é o primeiro relato de Avipoxvirus detectado em lesões semelhantes a tumores em uma marreca piadeira com caracterização molecular do vírus.(AU)