Avian Pox Research Articles

Molecular and pathological screening of the current circulation of fowlpox and pigeon pox virus in backyard birds

Avian pox is a disease that has devastating impacts on both poultry and wild bird species. Avian pox is caused by various strains of avipoxviruses (APV). Nevertheless, the virus has been detected in pigeons and chickens that are raised in backyard areas, leading to substantial financial damage for small-scale producers. There is a lack of comprehensive information regarding the transmission of APV among birds in the backyards and residential areas. Hence, the present investigation closely monitored and observed APV in domesticated birds residing in backyard areas, with the aim of impeding the transmission of the virus to nearby poultry farms. In 2023, a total of fifty backyard flocks were surveyed for the presence of avian pox disease. Sixteen backyards (14 pigeons and 2 chickens) exhibited warty nodular lesions on their heads and nonfeathered body parts. APV was confirmed in nodular lesions by polymerase chain reaction (PCR) amplification and genetic sequencing. All samples from the lesions showed successful amplification of the p4b locus (core protein p4b). Four confirmed samples were tested for pathogenicity on the chicken embryo chorioallantoic membrane (CAM). Histopathological examination revealed ballooning degeneration and numerous intracytoplasmic inclusion bodies (Bollinger bodies) in the ectoderm of the infected CAM. Phylogenetic analysis revealed that the strains clustered into main clade A, with 11 in subclade A2 and 5 in subclade A1. Amino acid identity showed 100% similarity between the vaccine (fowlpox/VSVRI/Egypt) and some detected strains (PP537574 and PP537575). In addition, the PP537576.1 to PP537580.1 and PP537582.1 to PP537585.1 had 2-point mutations compared to the fowlpox/VSVRI/Egypt vaccine. The overall finding of low biosecurity levels in the investigated backyard birds emphasizes the significance of establishing sanitary measures and control vectors to reduce virus transmission routes and disease severity. In conclusion, it is necessary to emphasize the tracking of APV in backyard birds. Concurrently, we advised enhancing hygiene protocols, vector management, and subsequent vaccination to restrict the occurrence of APV outbreaks and prevent their transmission to neighboring poultry farms. Furthermore, it is crucial to incorporate molecular studies in order to enhance the vaccine seeds for disease management.

Complete genome sequence analysis of Reticuloendotheliosis virus integrated in nonhomologous Avipoxvirus

Integration of nucleic acid sequences of Reticuloendotheliosis virus (REV) in Avipoxvirus（APV） has become commonplace. In this study, 4 strains of suspected Fowlpox virus (FPV) and 1 strain of suspected Pigeonpox virus (PPV) collected in Taiyuan, Shanxi Province were cultured in chicken embryos, and the 4b core protein gene was amplified by PCR, and the identity and genome similarity were determined by sequence analysis. The sequences between the end of ORF201 and the beginning of ORF203 of FPV and PPV were then amplified, sequenced, and subjected to sequence comparison to determine genome similarity. The results showed that the isolates were 4 strains of FPV and 1 strain of PPV. The 4 isolated strains of FPV belong to type A1 virus, with 100 % identity to each other and to the FWPV-09-Jilin strain isolated in Jilin, China, and the lowest identity to the type B2 virus TNPV5/NZL/2009, which is only 74 %. PPV belongs to type A2 virus, and its identity with local strain of fowlpox virus was 90.1 %, with the highest identity of 100 % with PPLH and ROPI/W370/ON/2012 and ow_2017_3 strains, which also belong to type A2 pigeonpox virus, and the lowest identity of 73.7 % with TNPV5/NZL/2009, a type B2 virus. The complete genome of REV sequences integrated into FPV and PPV were amplified, and 5 REV nucleic acid sequences were obtained after sequencing and concatenation, with lengths ranging from 7942 to 8005 bp. The identity analysis results indicate that it has high identity with isolates from Northeast China, Guangdong, and Guangxi regions in China. Based on its gp90 protein gene, the REV integrated into the poxvirus belong to type III, with the highest identity of 99.9% with strains such as APC-566 and CY1111, and the lowest identity with REV-Anhui1, at 95.4 %. The length of the pol gene varies among different strains of REV, and its encoded amino acid changes significantly after position 675, with deletions and alterations. This study indicates that all fowlpox viruses isolated in Taiyuan, Shanxi Province have integrated the entire REV gene sequence, with high identity between them. At the same time, it indicates that the pigeonpox virus isolate has also integrated the entire REV gene sequence, and has the highest identity with the integrated REV gene sequence in fowlpox virus.

The effect of the Stevia rebaudiana Morita II on the warts caused by fowl pox in Meleagris gallopavo as model study

O Objective: to evaluate the effect of leaves of Stevia rebaudiana Morita II on swelling caused by fowl pox in backyard turkeys of the Meleagris gallopavo species. Design/methodology/approach: Different percentages of ground stevia leaves (5.5, 15, 20 and 25%) combined with ground corn were evaluated and the reduction of avian pox in turkeys was evaluated. Results: The diet with 5% stevia leaves with corn was the most accepted combination by the turkeys; it also leads to immunomodulation to eliminate avian pox in a period of 30 days. Limitations on study/implications: One of the main limitations is the production of stevia matter, however, due to the required amount, it has the possibility of being applied in the feeding of these animals, this study has applications in animal health and food safety in turkeys. Findings/conclusions: The use of stevia in combination with corn could represent a natural alternative for the treatment of fowl pox and be profitable enough to prevent the death of turkeys.

Molecular Detection of Avian Poxvirus in Chickens and Pigeons of Diyala Province in Iraq

Fowlpox is an infectious viral disease affecting domestic and wild birds. The current study was conducted using PCR-based molecular detection to determine the avian pox virus (APV) and its genetic sequence. A total of 40 pigeons and 40 chickens suspected of APV were obtained from different bird markets. Following euthanasia, tissue samples were taken from the vents, eyes, wings, and beaks for molecular analysis. DNA extraction was focused on the core protein gene region (pb4). PCR results confirmed the presence of APV in all samples, generating specific cDNA bands of 329 bp. Four GenBank accession codes (OR670580, OR670581, OR670582, and OR670583) represented pigeon pox samples, whereas two GenBank accession numbers (OR619724 and OR619725) represented samples of fowlpox. A significant similarity of 99% was found by genetic analysis between the reference target sequences and the sequenced samples. In viral samples of fowlpox and avipoxvirus, nucleic acid variants (205 C > G and 204 T > C) were found with missense and silent effects on particular proteins (p.101Leu>Val and p.108Pro). Phylogenetic analysis organized the samples into clades representing fowlpox and pigeon pox viruses, showing close relationships with strains from different geographical regions. This study unequivocally demonstrates the susceptibility of both domestic and wild birds to avian pox, highlighting the pivotal role of phylogenetic analysis and molecular detection in elucidating novel perspectives on the genetic landscape of these viruses. Keywords: Fowl pox, Gene, Pigeon pox, Polymerase Chain Reaction

Development of a Multiplex PCR Assay for Rapid Differentiation of Fowlpox and Pigeonpox Viruses.

The aim of this study was to develop a multiplex PCR assay capable of rapidly differentiating two major Avipoxvirus (APV) species, Fowlpox virus (FWPV) and Pigeonpox virus (PGPV), which cause disease in bird species. Despite the importance of a rapid differentiation assay, no such assay exists that can differentiate the APV species without sequencing. To achieve this, species-specific target DNA fragments were selected from the fpv122 gene of FWPV and the HM89_gp120 gene of PGPV, which are unique to each genome. Nine samples collected from unvaccinated chickens, pigeons, and a turkey with typical pox lesions were genetically identified as FWPV and PGPV. The designed primers and target DNA fragments were validated using in silico analyses with the nucleotide Basic Local Alignment Search Tool. The multiplex PCR assay consisted of species-specific primers and previously described PanAPV primers (genus-specific) and was able to differentiate FWPV and PGPV, consistent with the phylogenetic outputs. This study represents the first successful differentiation of FWPV and PGPV genomes using a conventional multiplex PCR test. This assay has the potential to facilitate the rapid diagnosis and control of APV infections.

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.

Avipox: Morphology, Host Spectrum, Epidemiology, Symptoms, Diagnosis, Prevention and Treatment

Avian pox is an infectious, slow-spreading, highly contagious viral disease that has been reported in numerous number of species of birds. These affect domesticated and free-ranging birds, resulting in economic losses in the poultry industry. They are thought to be highly host-specific but certain factors have changed this specificity pattern. In recent times, the emergence of avian pox infection has drastically increased involving new species as well. Infection is commonly observed in anatomical locations where feathers are absent, such as the toes, legs, or head, as well as in the mucous membranes of the oral cavity and upper respiratory tract. Quails and hawks are usually unaffected, but chickens, turkeys, canaries, and pigeons are highly susceptible to infection. While death can occur in severely affected birds, the disease more commonly results in weight loss, stunted growth, and decreased egg production. It is interesting to observe that the ailment was initially recorded in feathered creatures in the seventeenth century. In our review, we conducted a comprehensive literature search to collect relevant data. This search was primarily carried out using reputable academic databases, including PubMed and Google Scholar. The specific search terms and keywords employed in these databases are Avipox and Fowl pox. Additionally, the references have been precisely cited to ensure transparency and provide readers with access to the sources used in our study. This article contains all the details of the Avipox virus-like morphology, host, prevention, and treatment

Fatal avian pox in a backyard flock of domestic ducks in Bangladesh

AbstractThis case study describes a fatal avian pox outbreak in a backyard flock of domestic ducks (Anas platyrhynchos domesticus) in Bangladesh. A total of six ducks of varying ages were affected and presented with solid tumour‐like masses on the legs. A 6.5‐month‐old female duck was presented for clinical examination, and a 2 cm3 solid, nodular mass was surgically excised from the left leg. Histopathological examination of the tumour mass revealed marked epidermal hyperplasia with ballooning degeneration and eosinophilic intracytoplasmic inclusion bodies, as well as severe proliferation and necrotising dermatitis, with marked heterophilic and histiocytic infiltration. Electron microscopy revealed numerous dumbbell‐shaped virus particles within the intracytoplasmic inclusion bodies on degenerating keratinocytes, confirming Avipoxvirus infection. This is the first case report of avian pox in ducks in Bangladesh.

Cell culture adaptation of Avipox viruses isolated from different species of birds

Avianpox (AP) is an infectious, slow spreading viral disease that has been reported to affect numerous species of birds including poultry. There is very limited information available regarding the molecular and biological characteristics of the avipox viruses (APVs) circulating in India. In the present study, APVs from fowl [FP/As- K(R)], pigeon [P2/ As- K9(R)] and duck [D2/ As- N] origin isolated from natural outbreaks of the disease in different areas of Assam were selected for adaptation in different cell culture. All the three isolates were propagated in chicken embryo fibroblast (CEF) primary cell culture and Vero cell line and their propagation was confirmed by observing virus specific cytopathic effects (CPE) and by performing PCR targeting the 4b gene of APV. All three isolates were adapted in the CEF primary culture with production of virus specific CPE. However, a high degree of CPE was observed in the cultures infected with the fowl isolate from an earlier passage (P-11) in comparison to the other two isolates. Even the time required for completion of CPE was considerably less in case of the fowl isolate. The log TCID50 of the fowl isolate was found to be 4.18 ± 0.11, 5.29 ± 0.06 and 6.29 ± 0.13, respectively in the 5th, 15th and 20th passage, which was higher in comparison to the other two isolates. Interestingly, none of the isolates showed any virus specific CPE in vero cell line on propagation till the 10th passage. Moreover, all the passages were found to be negative by PCR.

Cuteneous and diphtheritic forms of avian pox infections in a juvenile ostrich

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Avian Pox in New World Vultures: An Unnoticeable or Overlooked Infectious Disease?

Avian Pox in New World Vultures: An Unnoticeable or Overlooked Infectious Disease?

First report of Psittacid Avipoxvirus in Agapornis in Mexico

A postmortem study was performed on two lovebirds (Agapornis fischeri and Agapornis personatus) that had scabs in the periocular region and on the eyelid, as well as serous blepharitis. Microscopically, the eyelids showed ulcers, necrosis and serocellular crusts, severe hyperplasia of keratinocytes with eosinophilic intracytoplasmic inclusion bodies (Bollinger's bodies), bacterial colonies of gram-positive coccoid morphology and PAS-positive septate and 45° branching hyphae. The microbiological study identified the colonies as Staphylococcus spp. and Aspergillus fumigatus, respectively. Using molecular techniques, avian pox clade C was identified on the eyelid. This is the first report in Mexico of a case of avian pox in parrots associated with clade C Avipoxvirus

Improved status of the conservation reliant Oahu Elepaio through effective management and natural adaptation

AbstractThe Oahu Elepaio (Chasiempis ibidis) is an endangered forest bird endemic to the Hawaiian island of Oahu. The two most serious threats to the Oahu Elepaio are nest predation by nonnative black rats (Rattus rattus) and avian pox (Avipoxvirus spp.), a disease carried by nonnative mosquitoes. The Oahu Elepaio is conservation reliant because its continued existence depends on rat control. We used 27 years of data from 1995 to 2021 on pox prevalence, nest success, and fecundity with versus without rat control to reexamine the severity of these threats. Prevalence of avian pox declined over time. From 1995 to 2004, pox prevalence averaged 21% ± 4% per year and was positively related to annual rainfall. From 2005 to 2021, pox prevalence was only 2% ± 0.1% and despite several wet years there was no relationship with rainfall. The Oahu Elepaio appears to have evolved resistance to the pox variant currently in Hawaii. Elepaio nest success was higher with rat control (58% ± 1%) than without rat control (42% ± 6%). Nest success did not differ significantly between native tree species (52% ± 6%) and nonnative tree species (58% ± 6%) or between fruiting tree species (58% ± 1%) and nonfruiting species (61% ± 6%). Elepaio annual fecundity was higher with rat control (0.78 ± 0.02) than without rat control (0.48 ± 0.04) and varied among sites and years. The two primary threats to the species have been ameliorated through a combination of effective management and natural adaptation. The species' status should continue to improve if management is maintained, and someday, if patterns of natural adaptation continue, it could break free from conservation reliance.

Genetic characteristics and pathogenicity of avian pox virus for a new host, Cherry Valley breeder ducks in China

ABSTRACT Cherry Valley breeder ducks in Shandong province in northern China have experienced swollen eyes, lachrymation, pox scabs on glabrous or glabrous skin, depression and dysentery since 2021. The spread of this infectious disease has seriously affected the breeder ducks in major Cherry Valley duck farms in China. The virus causing clinical signs in Cherry Valley breeder ducks was isolated by chicken embryo inoculation. We successfully isolated a strain of duck pox virus from diseased breeder ducks by virus replication. We have also successfully conducted experiments for duck pox disease using the isolated strains to infect ducklings. By comparison with 22 pox viruses already published in GenBank, the virus strain obtained in this study was most homologous (about 99.7%) to the strain isolated from infected domestic ducks in Guangxi, China in 2014 (KJ192189), and belonged to the same A5 subtype. Since there were no previous cases of avian pox virus infecting white or Cherry Valley duck breeds, this study identified a new host for avian pox virus infection and provided theoretical support and data for the development of avian pox virus research. RESEARCH HIGHLIGHTS Avian pox virus can infect a new host type – Cherry Valley breeder ducks. The avian pox virus isolated from Cherry Valley breeder ducks showed highest identity with Guangxi hemp duck-derived avian pox virus. Cherry Valley breeder ducks were infected with avian pox virus of subtype A5.

Infecções fúngicas cutâneas secundárias à varíola aviária no Nordeste do Brasil

ABSTRACT: This study describes the epidemiological and clinical-pathological aspects of outbreaks of avian pox diagnosed in poultry associated with fungal co-infections. A retrospective study was carried out, and cases of avian pox with suspected associated fungal infection were selected. The slides were subjected to routine and special histochemical staining in cases of suspected fungal infection, in addition to performing the immunohistochemical technique. Macroscopically, there were nodular lesions with crust formation, and histologically, the lesions were characterized by hyperplasia of the spinous layer associated with multiple eosinophilic intracytoplasmic inclusions. In seven cases, morphologically compatible structures with fungi were verified through black impregnation with GMS and strongly stained in pink with PAS. The morphotintorial aspects were suggestive of fungi belonging to the genus Aspergillus sp. and Candida sp. The diagnosis of fungal co-infections was confirmed through immunohistochemistry, with positive immunostaining for fungi of the genus Aspergillus sp. (five cases) and Candida sp. (two cases). It is concluded that the occurrence of fungal co-infections secondary to the cutaneous lesions of avian pox represents a complicating factor of the disease, favoring the weakness of these animals and death. Therefore, the investigation of associated secondary agents is necessary.

Recombination of Goose Parvovirus VP3 Gene and Goose Interferon Ɣ Gene from Fowlpox Virus Immune Protection and Its Mechanism

Gosling plague (GP) is caused by goose parvovirus (GPV) gosling acute, subacute, and septic infectious diseases, commonly known as gosling plague. At present, the prevention and control of GP at home and abroad mainly adopts the method of immunizing female geese with attenuated vaccine. Goslings can be immunized, but there are still the phenomenon of dispersive virus and virulence reverse. It, therefore, is urgent to develop a new safe and effective vaccine. The recombinant avian pox virus vaccines rFPV-GoIFNγ, rFPV-GPV-VP3 and rFPV-GoIFNγ-VP3 were used to monitor their antibody levels and evaluate the protective mechanism of the vaccine in this study. This study lays a foundation for further in vivo testing of recombinant avian pox virus vaccine for goose parvovirus and provides a reference for the development of recombinant avian pox virus vaccine for other avian infectious diseases.

MORBIDITY AND MORTALITY OF HAWAIIAN GEESE (BRANTA SANDVICENSIS) AND LAYSAN ALBATROSS (PHOEBASTRIA IMMUTABILIS) ASSOCIATED WITH RETICULOENDOTHELIOSIS VIRUS.

Only one virus, Avipox, has been documented previously in wild birds in Hawaii. Using immunohistochemistry and PCR, we found that two native threatened Hawaiian Geese (Branta sandvicensis), one with multicentric histiocytoma and the other with toxoplasmosis, and one Laysan Albatross (Phoebastria immutabilis) with avian pox were infected with reticuloendotheliosis virus (REV). The virus was isolated from one of the geese by cell culture. Surveys of other Hawaiian geese with various pathologies, avian pox cases, and pox viral isolates using PCR failed to reveal REV, suggesting that the virus is uncommon, at least in samples examined. The full genome of the Gag, Pol, and Env genes were sequenced for all three infected birds and revealed geographic divergence of the Pol gene, suggesting it to be under strong selective pressure. Our finding of REV in Hawaii makes this only the second virus documented in native Hawaiian birds associated with pathology. Moreover, the presence of REV in a pelagic seabird is unusual. Future surveys should seek the reservoir of the virus in efforts to trace its origins.

Transcriptomic responses of Galápagos finches to avian poxvirus infection.

Emerging pathogens can have devastating effects on naïve hosts, but disease outcomes often vary among host species. Comparing the cellular response of different hosts to infection can provide insight into mechanisms of host defence. Here, we used RNA-seq to characterize the transcriptomic response of Darwin's finches to avian poxvirus, a disease of concern in the Galápagos Islands. We tested whether gene expression differs between infected and uninfected birds, and whether transcriptomic differences were related either to known antiviral mechanisms and/or the co-option of the host cellular environment by the virus. We compared two species, the medium ground finch (Geospiza fortis) and the vegetarian finch (Platyspiza crassirostris), to determine whether endemic Galápagos species differ in their response to pox. We found that medium ground finches had a strong transcriptomic response to infection, upregulating genes involved in the innate immune response including interferon production, inflammation, and other immune signalling pathways. In contrast, vegetarian finches had a more limited response, and some changes in this species were consistent with viral manipulation of the host's cellular function and metabolism. Many of the transcriptomic changes mirrored responses documented in model and in vitro studies of poxviruses. Our results thus indicate that many pathways of host defence against poxviruses are conserved among vertebrates and present even in hosts without a long evolutionary history with the virus. At the same time, the differences we observed between closely related species suggests that some endemic species of Galápagos finch could be more susceptible to avian pox than others.

Evaluation of minimally invasive sampling methods for detecting Avipoxvirus: Hummingbirds as a case example.

Avian pox is a common avian virus that in its cutaneous form can cause characteristic lesions on a bird's dermal surfaces. Detection of avian pox in free-ranging birds historically relied on observations of visual lesions and/or histopathology, both which can underestimate avian pox prevalence. We compared traditional visual observation methods for avian pox with molecular methods that utilize minimally invasive samples (blood, toenail clipping, feathers, and dermal swabs) in an ecologically important group of birds, hummingbirds. Specifically, avian pox prevalence in several species of hummingbirds were examined across multiple locations using three different methods: (1) visual inspection of hummingbirds for pox-like lesions from a long-term banding data set, (2) qPCR assay of samples from hummingbird carcasses from wildlife rehabilitation centers, and (3) qPCR assay of samples from live-caught hummingbirds. A stark difference in prevalences among these three methods was identified, with an avian pox prevalence of 1.5% from banding data, 20.4% from hummingbird carcasses, and 32.5% from live-caught hummingbirds in California. This difference in detection rates underlines the necessity of a molecular method to survey for avian pox, and this study establishes one such method that could be applied to other wild bird species. Across all three methods, Anna's hummingbirds harbored significantly higher avian pox prevalence than other species examined, as did males compared with females and birds caught in Southern California compared with Northern California. After hatch-year hummingbirds also harbored higher avian pox prevalences than hatch-year hummingbirds in the California banding data set and the carcass data set. This is the first study to estimate the prevalence of avian pox in hummingbirds and address the ecology of this hummingbird-specific strain of avian pox virus, providing vital information to inform future studies on this charismatic and ecologically important group of birds.

Detection and molecular characterization of Avipoxvirus in Culex spp. (Culicidae) captured in domestic areas in Rio de Janeiro, Brazil

Avian pox is a highly contagious poultry disease that causes significant economic losses. Mosquitoes belonging to the genus Culex (Diptera: Culicidae) have a fundamental role in disseminating Avipoxvirus (Poxviridae). This study proposes investigating the presence of Avipoxvirus (APV) DNA in Culex spp. from Rio de Janeiro to determine its frequency and perform a phylogenetic analysis based on the core like the 4b protein (p4b) gene. The detection of APVs was conducted individually on four hundred Culex spp. mosquitoes. A total of 12.23% (47/384) of the Culex spp. were positive in the PCR. Sequencing the p4b gene revealed that this study’s sequences displayed 98.8–99% identity with Fowlpoxvirus (FWPW) sequences available in GenBank. In the phylogenetic analysis, these APVs were clustered in the A1 subclade together with FWPW sequences from several countries. The evolutionary distance of the p4b gene was 0.61 ± 0.21% in rural areas and 0.38 ± 0.16% in peri-urban areas. The current investigation is the first study to report the detection of APVs in field-caught mosquitoes. Moreover, a high frequency of APV DNA was observed in Culex spp. captured in domestic areas, where backyard poultry is present. This data demonstrates the importance of implementing control measures for Culex spp. to mitigate the transmission of APVs in backyard poultry in Rio de Janeiro.