Avian Pox Research Articles

Occurrence of Avian Pox Outbreaks in Wild and Canary Commercial Breedings. Diagnosis through Electron Transmission Microscopy and Histopathology Techniques

Occurrence of Avian Pox Outbreaks in Wild and Canary Commercial Breedings. Diagnosis through Electron Transmission Microscopy and Histopathology Techniques

Active and passive disease surveillance in wild turkeys (Meleagris gallopavo) from 2008 to 2018 in Pennsylvania, USA

AbstractThere are increasing concerns about the effects of disease on wild turkeys (Meleagris gallopavo). Yet, many management agencies lack adequate data on wild turkey diseases and pathogens to address this concern. Toward that end, the Pennsylvania Game Commission increased surveillance efforts on wild turkeys beginning in 2013 (referred to hereafter as the enhanced surveillance period). From 2008–2018, 121 wild turkeys from Pennsylvania were submitted for necropsy, with 102/121 (84.3%) submitted during the enhanced surveillance period (2013–2018). We examined cases to determine causes of morbidity/mortality through gross and microscopic examinations and ancillary tests. The most common causes of morbidity/mortality in the examined wild turkeys were avian pox (66/121; 54.5%), chronic dermatitis (15/121; 12.4%), and trauma (10/121; 8.3%). We diagnosed additional diseases for the first time or more frequently during the enhanced surveillance period, including histomoniasis (7/121; 5.7%) and infectious sinusitis (1/121; 0.8%). Skin lesions were the most common cause of submission (94/121; 77.7%) and were most often attributed to avian pox (66/94, 70.2%), chronic dermatitis (15/94; 16.0%), or lymphoproliferative disease (3/94; 3.2%). During 2013–2018, tissues and sera were collected from any diagnostic cases and hunter‐harvested turkeys to create a tissue repository. We used these samples to test for infection or exposure to specific pathogens. We found that 75.3% (61/81) of wild turkeys were positive for lymphoproliferative disease virus, 61.9% (52/84) for Heterakis gallinarum, 28.6% (10/35) for Toxoplasma gondii, and 15.6% (15/32) for Borrelia burgdorferi. We detected antibodies (indicating exposure) to avian paramyxovirus‐1 in 34.9% (22/63) of the wild turkeys and West Nile virus in 21% (13/62), but none were seropositive to influenza A viruses (0/62; 0%). The presence of diseases and pathogens in wild turkeys in Pennsylvania are being defined through active and passive surveillance approaches. Such data can begin to address the broader questions of disease impacts on wild turkey populations.

Genomic associations with poxvirus across divergent island populations in Berthelot's pipit

Understanding the mechanisms and genes that enable animal populations to adapt to pathogens is important from an evolutionary, health and conservation perspective. Berthelot's pipit (Anthus berthelotii) experiences extensive and consistent spatial heterogeneity in avian pox infection pressure across its range of island populations, thus providing an excellent system with which to examine how pathogen‐mediated selection drives spatial variation in immunogenetic diversity. Here, we test for evidence of genetic variation associated with avian pox at both an individual and population‐level. At the individual level, we find no evidence that variation in MHC class I and TLR4 (both known to be important in recognising viral infection) was associated with pox infection within two separate populations. However, using genotype‐environment association (Bayenv) in conjunction with genome‐wide (ddRAD‐seq) data, we detected strong associations between population‐level avian pox prevalence and allele frequencies of single nucleotide polymorphisms (SNPs) at a number of sites across the genome. These sites were located within genes involved in cellular stress signalling and immune responses, many of which have previously been associated with responses to viral infection in humans and other animals. Consequently, our analyses indicate that pathogen‐mediated selection may play a role in shaping genomic variation among relatively recently colonised island bird populations and highlight the utility of genotype‐environment associations for identifying candidate genes potentially involved in host‐pathogen interactions.

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.

RETROSPECTIVE MORTALITY REVIEW OF TUFTED PUFFINS (FRATERCULA CIRRHATA) AT A SINGLE INSTITUTION (1982-2017).

Tufted puffins (Fratercula cirrhata) are commonly exhibited in zoologic institutions across the world, yet there is a paucity of information on causes of mortality in managed populations. This retrospective review reports the pathologic findings associated with 91 tufted puffins at a single institution over 35 years from 1982 to 2017. Common pathologic findings were evaluated by age at death, sex, year, and season. With the exception of neonates, the leading pathologic finding across all age classes was aspergillosis, particularly in adults. Hemoparasitism, predation, and trauma were also frequent causes of mortality. Neonatal mortality was common and primarily caused by omphalitis, yolk sac disease, and bacterial septicemia, with most cultures revealing Escherichia coli. This study also provides documentation of mortality in tufted puffins secondary to avian pox and suspected toxoplasmosis. Understanding morbidity and mortality trends within a population allows institutions to form management plans and implement practices to improve outcomes and survival.

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.

Isolation and Molecular Characterization of Turkey Pox Virus from Maharashtra, India

Avian pox diseases are contagious and slow spreading viral infections in birds. The present study was aim to, isolate and molecular characterization of turkeypox virus from a clinical case. Ten out of the twelve scab lesions sample collected from clinically suspected cases were positive for avian pox viurs (APV) based on virus isolation and polymerase chain reaction. We conducted genetic characterization of the APV strain. The phylogenetic analyses of P4b gene APV genome indicated that, avian poxviruses fragments sequenced in this study clustered along the A clade of avipoxviruses, genetically related to Indian fowl pox virus isolated from chicken, showing 99% homology.

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.

In ovo inhibition of avian pox virus replication by mangosteen rind and red ginger ethanolic extracts.

Background and Aim:Avian pox is a contagious disease caused by the avian pox virus (APV). Mangostin and γ-mangostin in mangosteen rind (MR) and gingerol in red ginger (RG) exhibit antiviral activity. In this study, we evaluated the effect of MR and RG ethanolic extracts on APV based on pock lesions on the chorioallantoic membrane (CAM) of specific pathogen-free (SPF) embryonated chicken eggs (ECEs).Materials and Methods:Three APVs from chicken isolates (C1, C2, and C3), one APV from a pigeon isolate (P), 1.5% and 3% MR ethanolic extract, 5% and 10% RG ethanolic extract, and a combination of 1.5% MR and 5% RG at 0.1 mL/egg were inoculated in ovo (7th day incubation, chorioallantoic route) in SPF ECEs. A control group inoculated in ovo with APV alone was also established. Each treatment consisted of three replicates. Parameters including embryo survival, CAM lesions, and average number of pock lesions were determined.Results:In ovo inoculation of MR and RG ethanolic extracts was not harmful to the ECEs and did not induce CAM lesions. The average number of pock lesions in the control group (C1, C2, C3, and P) was 35, 14, 10, and 17, respectively, whereas in all treatment groups, the number was 0, except in the 5% RG group of C1, which had a value of 10.Conclusion:In ovo inoculation of 1.5% and 3% MR, 5% and 10% RG, and the combination of 1.5% MR plus 5% RG ethanolic extracts at 0.1 mL/egg inhibit APV by reducing the number of pock lesions on the CAM of the ECE.

Characterization of Avian Pox in a Ruffed Grouse (Bonasa umbellus) from Pennsylvania.

A free-ranging, adult male ruffed grouse (Bonasa umbellus) was harvested by a hunter during November 2019 in Forest County, PA. The bird was submitted for necropsy due to a skin mass on its left leg. Upon necropsy, two proliferative skin masses were grossly visible, one on the left leg and one on the cere. An additional mass was present on the oropharyngeal mucosa covering the hard palate. These masses were diagnosed as avian pox based on histopathologic and cytologic findings, including marked epithelial hypertrophy, hyperplasia, vacuolar degeneration with eosinophilic stippling, and intracytoplasmic inclusion bodies. An avipoxvirus was detected using PCR and was identified as fowlpox virus through sequencing of the 4b core gene segment. The avipoxvirus from this case showed genetic similarity to isolates from Eastern wild turkeys (Meleagris gallopavo silvestris).

Pathogenic microorganisms associated with gulls and terns (Laridae)

The monograph reviews viruses, bacteria, microfungi and protozoa pathogenic to homeotherm vertebrates (including humans) associated with birds of the family Laridae (larids, for short). The survey also presents a review of larid microbial diseases worldwide: a total of 569 determined microbial morbidity and mortality events in larids have been reported. The dominating disease is avian botulism (in fact, microbial toxicosis) representing 38% of all recorded microbial disease events. Additional relatively frequent and important diseases in larids are salmonellosis (10% of all recorded microbial events), aspergillosis (9%), avian cholera (9%), Newcastle disease (5%) and ornithosis (5%), while other microbial diseases have occurred in < 5% of the reported events: West Nile virus disease, haemosporidiosis, avian influenza, avian tuberculosis, toxoplasmosis, coccidiosis, avian pox, tick-borne virus diseases, circovirus infection, avian papilloma, erysipelas, candidosis, staphylococcosis, sarcosporidiosis, cryptosporidiosis, necrotic clostridial enteritis, colibacillosis, babesiosis, calicivirus and avian bornavirus infections. However, many observations indicate that some microbial diseases of larids have remained unidentified and additional investigations about infectious morbidity and mortality in them is warranted.

A Review on the Prevalence of Poxvirus Disease in Free-Living and Captive Wild Birds

Avian pox is a widespread infection in birds caused by genus Avipoxvirus pathogens. It is a noteworthy, potentially lethal disease to wild and domestic hosts. It can produce two different conditions: cutaneous pox, and diphtheritic pox. Here, we carry out an exhaustive review of all cases of avian pox reported from wild birds to analyze the effect and distribution in different avian species. Avian poxvirus strains have been detected in at least 374 wild bird species, a 60% increase on a 1999 review on avian pox hosts. We also analyze epizootic cases and if this disease contributes to wild bird population declines. We frequently observe very high prevalence in wild birds in remote island groups, e.g., Hawaii, Galapagos, etc., representing a major risk for the conservation of their unique endemic avifauna. However, the difference in prevalence between islands and continents is not significant given the few available studies. Morbidity and mortality can also be very high in captive birds, due to high population densities. However, despite the importance of the disease, the current detection rate of new Avipoxvirus strains suggests that diversity is incomplete for this group, and more research is needed to clarify its real extent, particularly in wild birds.

Detection of Laryngotracheitis Virus in Poultry Flocks with Respiratory Disorders in Slovenia.

Infectious laryngotracheitis (ILT) is an acute, highly contagious infectious disease of the upper respiratory tract in chickens and other poultry species that causes significant economic losses in countries worldwide. Between 2017 and 2019, seven outbreaks of mild to severe respiratory disorders with high suspicion of ILT occurred in commercial and backyard poultry flocks in Slovenia. In all submissions, infection with ILT virus (ILTV) was confirmed by PCR, which is the first report of ILT in Slovenia. Circulating ILT strains were characterized by the sequence and phylogenetic analysis of two fragments of the ICP4 gene. Four strains—three detected in non-vaccinated flocks and one in a flock vaccinated against ILT—were identical or very similar to the chicken embryo–origin live virus vaccines, and the other three were closely related to Russian, Chinese, Australian, and American field strains and to tissue culture origin vaccine strains. As in other diseases, coinfections with other respiratory pathogens in confirmed ILT cases may cause a more severe condition and prolong the course of the disease. In our study, coinfections with Mycoplasma synoviae (7/7 tested flocks), infectious bronchitis virus (5/5 tested flocks), Mycoplasma gallisepticum (4/7 tested flocks), Ornithobacterium rhinotracheale (3/4 tested flocks), and avian pox virus (1/2 tested flocks) were confirmed, indicating the importance of these pathogens in the occurrence of ILT infections.

Inclusive Review on Common emerging viral infections affecting quail

Nowadays, the quails are documented as alternative species over other poultry species. The rapid growth rate, low feed necessities, high nutritional value of meat & eggs, and short production periods are all advantages of the quail. Quail are being held in greater numbers and varieties for food production, research, and other purposes. However, there are some challenges facing the quail industry as quails are susceptible to some viral diseases that have harmful effects as quail bronchitis, avian influenza, Newcastle disease, coronavirus infection, avian encephalomyelitis, Marek's disease, lymphoid leukosis, reticuloendotheliosis tumors, and avian pox. These viral diseases are causing significant financial losses due to poor feed conversion, decreased hatchability, and increased mortality in the quail industry, and so on. Therefore, the aim of the existing manuscript is intended to present a review about the extremely vital emergent viral infections upsetting quails all over the world accompanied by information on their prevention and control.

A Case Report of Outbreak Avian Pox Virus from Layer Chickens and a Pigeon in Yogyakarta, Indonesia

A Case Report of Outbreak Avian Pox Virus from Layer Chickens and a Pigeon in Yogyakarta, Indonesia

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%).

Attenuation of a Turkeypoxvirus field strain as an alternative to heterologous vaccination in turkeys

Avian pox can severely impact turkey production systems. Vaccination programs in Mexico use commercially available Fowlpoxvirus vaccines, that are used across different bird species. Nonetheless, there are reports of sporadic disease outbreaks among vaccinated turkeys, which suggest that heterologous vaccines may provide limited immunity, presenting the need to develop homologous vaccines that can better protect turkeys. This study compared the protection granted to turkey chicks by a commercial Fowlpoxvirus vaccine and by a live attenuated Turkeypoxvirus vaccine after a challenge with a field isolated Turkeypoxvirus virus. Histopathology, polymerase chain reaction, and sequencing of DNA were used for viral identification. A Turkeypoxvirus strain was first isolated in chicken embryo lesions, and subsequently adapted through serial passes in chorioallantoic membrane to produce the homologous vaccine. The attenuated virus was used as a vaccine when a 104.4 embryo ID50/mL titre was reached. Three groups of three-week-old turkey chicks were used for challenge experiments. Subjects in Group 1 were immunized with the attenuated Turkeypoxvirus vaccine (homologous vaccine). Chicks in Group 2 were vaccinated with the commercially available heterologous vaccine (Fowlpoxvirus). Subjects in Group 3 were not vaccinated and received only saline solution (control group). Two weeks after vaccination, animals from Group 1 reached a 97.7 ND50 seroneutralization titre, while levels reached in Group 2 birds and in control chicks were 11.7 ND50 (Group 2) and zero, respectively. At this time, all groups were challenged with a suspension of a field-isolated Turkeypox virus. The homologous vaccine afforded 100% protection in Group 1 (10/10 individuals), while only 10% (1/10) of individuals in Group 2 were protected by the commercial heterologous Fowlpoxvirus vaccine. None of the non-immunized birds in Group 3 were protected (0/10). These results show that the homologous vaccine afforded a greater protection against a Turkeypox virus infection than that observed for the heterologous vaccine, and that a homologous vaccine can be efficiently produced by isolating and attenuating the virus from turkeypox lesions, through chorioallantoic membrane serial passes.

Avipoxvirus detected in tumor-like lesions in a white-faced whistling duck (Dendrocygna viduata)

ABSTRACT: 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.

Plasmodium relictum

Plasmodium relictum is a widespread haemosporidian parasite infecting over 300 bird species from all continents except Antarctica. Based on sequences of the cytochrome b gene, that has become the barcoding region for avian haemosporidians, five different mitochondrial haplotypes (lineages) have been linked to P. relictum (SGS1, GRW04, GRW11, LZFUS01, and PHCOL01). Culex mosquitoes are the main vectors in P. relictum transmission, while other potential vectors include Aedes, Lutzia, Culiseta, and Anopheles species. Introduction of the lineage GRW04 to Hawaii in the first half of the 20th century, where Culex vectors were previously introduced – in synergy with anthropogenic impacts and infections of other pathogens (i.e., avian pox virus) – resulted in dramatic population declines of native bird species. As a result of this and other invasion events, P. relictum is nowadays catalogued as one of the 100 world’s worst invasive species.

TaqMan quantitative real-time PCR for detecting Avipoxvirus DNA in various sample types from hummingbirds.

BackgroundAvian pox is a viral disease documented in a wide range of bird species. Disease-related detrimental effects can cause dyspnea and dysphagia, and birds with high metabolic requirements, such as hummingbirds, are thus especially vulnerable to the pathogen. Hummingbirds have a strong presence in California, especially in urban environments. However, little is understood regarding the impact of pox virus on hummingbird populations. Currently, diagnosing a pox infection relies on obtaining a tissue biopsy, which poses significant risks to birds and challenges in the field. Understanding the ecology of hummingbird pox viral infections could be advanced by a minimally invasive ante-mortem diagnostic method. Our aim was to address whether pox infections can be diagnosed using integumentary system samples besides tissue biopsies. To meet this goal, we tested multiple integumentary sample types using a quantitative real-time PCR assay. A secondary study goal was to determine which sample types (ranging from minimally to highly invasive sampling) were optimal for identifying infected birds.Methodology and principal findingsPox-like lesion tissue, pectoral muscle, feathers, toenail clippings, blood, and swabs (both pox-like lesion tissue and non pox-like lesion tissue) were taken from live birds and carcasses of two species of hummingbirds found in California. To maximize successful diagnosis, especially for samples with low viral load, a real-time quantitative PCR assay was developed for detecting the hummingbird-specific Avipoxvirus 4b core protein gene. Avipoxvirus DNA was successfully amplified from all sample types obtained from 27 individuals. These results were compared to those of conventional PCR and comparisons were also made among sample types, utilizing lesion tissue samples as the gold standard.Conclusions and significanceHummingbird avian pox can be diagnosed without relying on tissue biopsies. We identify that feather samples, of which contour feathers yielded the best results, can be used for diagnosing infected birds, thus reducing sampling risk. In sum, the real-time PCR assay detected viral DNA in various integumentary system sample types and will be useful in future studies of hummingbird disease ecology.