Serological and molecular epidemiology of canine adenovirus type 1 in red foxes (Vulpes vulpes) in the United Kingdom

Canine Adenoviruses in Wildlife: Role in At-Risk Species Conservation and Interface with Domestic Animals

Canine adenovirus type 1 (CAdV-1) and type 2 (CAdV-2) are well known pathogens of domestic dogs but are little investigated in wild animals. The few available studies about CAdV-1 in wild animals show that it circulates in various species and that transmission of the virus in the interface between wildlife and domestic animals is a frequent event. Furthermore, wild animals are usually subject to asymptomatic infections, but cases of serious and fatal diseases have been documented, with possible effects on the conservation of the species. In contrast, CAdV-2 infection was reported only recently and sporadically in some wild animals, with few data regarding its pathogenic role in these species. However, the real prevalence of these viruses in wildlife is still uncertain due to the use of serological tests that are largely unable to distinguish antibodies against CAdV-1 and CAdV-2. This review, reporting all the data currently available on CAdV-1 and CAdV-2 infection in wild animals, highlights the importance of these pathogens for wildlife conservation and their role in the potential transmission of the infection to domestic dogs.

Complete Genome Characterization of Canine Adenovirus From Türkiye With Next-Generation Sequencing

BACKGROUND

Determining the complete genome sequence data of adenoviruses has recently become greatly important due to their use by scientists as vectors in cancer studies and other fields, including vaccine development. However, the GenBank database currently has few complete genome sequences of adenoviruses, which are known for their large genomes. To address this gap, we analysed next-generation sequencing data obtained from our previous study to provide the complete genome sequence of the canine adenovirus-2 strain.

METHODS

For the obtained canine adenovirus-2 strain (OQ596341), comparative genomics, recombination and phylogenetic analysis were conducted. This sequence was compared and phylogenetically analysed with the 20 complete genome sequences of canine adenovirus previously reported in GenBank worldwide, as well as partial E3 ORFA sequences obtained from Türkiye.

RESULTS

The nucleotide similarity rates of the sequence obtained from this study with other CAdV-2 whole genomes are over 99.04%. The gene alignment results reveal that the OQ596341 was found to be closely related to the AC000020 reference genome and LC557011. There are two recombination events related to the genome in this study. Comparisons with other complete genome sequences revealed several previously unseen mutations. These mutations include H34Y in the E1A gene; P55A in the E1B 55K gene; D13N and D202N in the IVa2 gene; K679R, V934I and K989N in the Pol gene; E205K in the pTP gene; T455A in the pIIIa gene; A310V in the V gene; G151R in the protease gene; E268K in the 100K gene; G66S and G141S in the 33K gene; T14A, E250K, D287N and I293T in the E3 ORFA gene; and L193F in the E434K gene. Moreover, a comparison with partial sequences obtained from Türkiye revealed the E250K mutation in the E3 ORFA gene, which we report for the first time in Türkiye.

CONCLUSIONS

The complete CAdV-2 genome sequence obtained in the present study is the first sequence from Europe. Comparative analysis with other genomes revealed some unique mutations. This study is the first to report the E250K amino acid change in the E3 ORFA gene in Türkiye. We anticipate that this data can be used in future CAdV-2 vaccine development studies. Further studies are recommended to evaluate the impact of these mutations on viral tropism and other host interactions.

Molecular Detection of Viral and Bacterial Pathogens in Red Foxes (Vulpes vulpes) from Italy

Animals, including wildlife, are part of One-Health concept since many infectious diseases can affect both humans and animals. In this study, 126 red foxes (Vulpes vulpes) from Northern Italy in 2022-2023 were tested by molecular assays for Protoparvovirus carnivoran 1 (PPVC-1), Canine adenovirus type 1 and 2 (CAdV-1 and CAdV-2), Circovirus canine (CanineCV), Canine distemper virus (CDV), and Leptospira spp. A total of 39 of 126 (30.9%) red foxes were infected with at least one pathogen and five of these were coinfected: 20/126 (15.9%) red foxes tested positive for PPVC-1, 3/126 (2.4%) for CAdV, 20/126 (15.9%) for CanineCV, and 2/126 (1.6%) for Leptospira spp. DNA. No foxes tested positive for CDV RNA. The pathogens identified were genetically analysed. New findings were reported such as a fox with multiple feline panleukopenia virus (FPV) and canine parvovirus type 2b (CPV-2b) infection associated with quasispecies dynamics, typical genetic characteristics of the identified CanineCV, and the first detection in red foxes of Leptospira ST198 related to L. interrogans serogroup Australis. Further studies are necessary to investigate the transmission between domestic animals and wildlife and to understand the role of red foxes in the maintenance of these pathogens not only in the wild but also in urban and peri-urban environments.

Five families of diverse DNA viruses comprehensively restructure the nucleus

Many viruses have evolved ways to restructure their host cell's nucleus profoundly and unexpectedly upon infection. In particular, DNA viruses that need to commandeer their host's cellular synthetic functions to produce their progeny can induce the condensation and margination of host chromatin during productive infection, a phenomenon known as virus-induced reorganization of cellular chromatin (ROCC). These ROCC-inducing DNA viruses belong to 5 families (herpesviruses, baculoviruses, adenoviruses, parvoviruses, and geminiviruses) that infect a wide range of hosts and are important for human and ecosystem health, as well as for biotechnology. Although the study of virus-induced ROCC is in its infancy, investigations are already raising important questions, such as why only some DNA viruses that replicate their genomes in the nucleus elicit ROCC. Studying the shared and distinct properties of ROCC-inducing viruses will provide valuable insights into viral reorganization of host chromatin that could have implications for future therapies that target the viral life cycle.

A One-Year Retrospective Analysis of Viral and Parasitological Agents in Wildlife Animals Admitted to a First Aid Hospital

This study aimed to provide information on the presence and frequency of viral and parasitic agents in wildlife presented to a Veterinary Teaching Hospital in 2020-2021. Serum and faecal samples were collected from 50 rescued animals (roe deer, fallow deer, foxes, badgers, pine martens, and porcupines) and examined by serological, molecular, and parasitological techniques. Transtracheal wash (TTW) was also collected post-mortem from roe deer. Overall, the results of the different techniques showed infections with the following viral and parasitic agents: Bovine Viral Diarrhea Virus, Small Ruminant Lentiviruses, Kobuvirus, Astrovirus, Canine Adenovirus 1, Bopivirus, gastrointestinal strongyles, Capillaria, Ancylostomatidae, Toxocara canis, Trichuris vulpis, Hymenolepis, Strongyloides, Eimeria, Isospora, Dictyocaulus, Angiostrongylus vasorum, Crenosoma, Dirofilaria immitis, Neospora caninum, Giardia duodenalis, and Cryptosporidium. Sequencing (Tpi locus) identified G. duodenalis sub-assemblages AI and BIV in one roe deer and one porcupine, respectively. Adult lungworms collected from the TTW were identified as Dictyocaulus capreolus (COX1 gene). This is the first molecular identification of G. duodenalis sub-assemblage AI and D. capreolus in roe deer in Italy. These results show a wide presence of pathogens in wild populations and provide an overview of environmental health surveillance.

Distribution and diversity of dog parvoviruses in wild, free-roaming and domestic canids of Newfoundland and Labrador, Canada

Some parvoviruses of carnivorans can infect multiple host species. Since many canine parvoviruses were only discovered recently, their host-range is still unexplored. We examined the host distribution and diversity of five dog parvoviruses in four canine populations from Newfoundland and Labrador, Canada, and investigated the potential for these viruses to cross the species barriers. Canine bocavirus 2 (CBoV-2) and the minute virus of canines were detected in stool from free-roaming dogs from Labrador (5/48 [10.4%] and 3/48 [6.3%], respectively) and two different CBoV-2 variants were identified. Canine bufavirus was identified in stool from free-roaming dogs (1/48, 2.1%) and foxes (3/80, 3.8%) from Labrador, but two different variants were observed in the two host species. The variant found in foxes was highly divergent from previously identified strains. Two cachavirus 1 variants, genetically similar to those circulating in other Canadian wildlife, were found in spleens from Newfoundland coyotes (3/87, 3.5%). Canine parvovirus type 2 (CPV-2) was found in stool from free-roaming dogs from Labrador (2/48, 4.2%) and in spleens from Newfoundland coyotes (3/87, 3.5%). Comparing CPV-2 sequences from these hosts to those retrieved from local symptomatic domestic dogs revealed the presence of a highly heterogeneous viral population as detected strains belonged to five different clades. The close relationship between CPV-2a strains from a dog and a coyote suggests the occurrence of viral transfer between wild and domestic canids. The identification of highly related strains with a similar molecular signature characteristic of older CPV-2 strains in free-roaming and domestic dogs suggests a probable common ancestry and that older CPV-2 strains, which have not been identified in dogs since the 1990s, persist in this part of Canada. Follow-up studies should evaluate samples from a larger number of animals and host species to extensively investigate the possible occurrence of cross-species transmission for recently discovered parvoviruses.

Adenovirus surveillance in wild carnivores from Brazil

Landscape transformation favors the spread of new pathogens that can be shared between domestic and wild animals. Certain adenoviruses (e.g., canine adenovirus 1 and 2, family Adenoviridae) can infect domestic and wild carnivores. In domestic canids, these viruses are associated with hepatic and respiratory diseases (among others). Nevertheless, information regarding adenovirus pathogenicity and molecular features in wild carnivores is still limited. Herein we surveyed adenovirus in free-ranging carnivores from Brazil. Total DNA was extracted from and subsequently tested by a nested panPCR in spleen and/or lung of 52 carnivores, representing species of the following families: Canidae (n = 4), Felidae (n = 3), Mustelidae (n = 2) and Procyonidae (n = 2). The obtained sequences were compared to others available at GenBank. Available tissue samples from the positive cases were evaluated histopathologically. One out of 52 (1.9%, CI 95%, 0.0-5.7%) carnivores was positive; a roadkilled ocelot (Leopardus pardalis). The obtained sequence presented a low deduced amino acid (78.1%) similarity with the closest adenovirus, identified in a pinniped from the United States of America. This fact and its detection in a novel host suggest it may be representative of a novel species and denominated ocelot adenovirus 1. None of the gross and microscopic findings of the positive case were associated with adenovirus. To the authors' knowledge, this is the first report of adenovirus in wild felids of South America and the second worldwide. Further studies are necessary to assess the epidemiology and potential pathogenicity of this agent in wild carnivores.

Detection and Genetic Characterization of Canine Adenoviruses, Circoviruses, and Novel Cycloviruses From Wild Carnivores in Italy

Wild carnivores are known to play a role in the epidemiology of several canine viruses, including canine adenoviruses types 1 (CAdV-1) and 2 (CAdV-2), canine circovirus (CanineCV) and canine distemper virus (CDV). In the present study, we report an epidemiological survey for these viruses in free ranging carnivores from Italy. A total of 262 wild carnivores, including red foxes (Vulpes vulpes), wolves (Canis lupus) and Eurasian badgers (Meles meles) were sampled. Viral nucleic acid was extracted and screened by real-time PCR assays (qPCR) for the presence of CAdVs and CanineCV DNA, as well as for CDV RNA. CAdV-1 DNA was detected only in red foxes (4/232, 1.7%) whilst the wolves (0/8, 0%) and Eurasian badgers (0/22, 0%) tested negative. CanineCV DNA was detected in 4 (18%) Eurasian badgers, 4 (50%) wolves and 0 (0%) red foxes. None of the animals tested positive for CDV or CAdV-2. By sequence and phylogenetic analyses, CAdV-1 and CanineCV sequences from wild carnivores were closely related to reference sequences from domestic dogs and wild carnivores. Surprisingly, two sequences from wolf intestines were identified as cycloviruses with one sequence (145.20-5432) displaying 68.6% nucleotide identity to a cyclovirus detected in a domestic cat, while the other (145.201329) was more closely related (79.4% nucleotide identity) to a cyclovirus sequence from bats. A continuous surveillance in wild carnivores should be carried out in order to monitor the circulation in wildlife of viruses pathogenic for domestic carnivores and endangered wild species.

Difference Analysis Between Canine Adenovirus Types 1 And 2

Canine adenoviruses (CAdVs) include type 1 (CAdV-1, virulent strain) and type 2 (CAdV-2, attenuated strain). In recent years, the incidences of CAdV infections are increasing. However, they are difficult to distinguish when the symptoms are untypical. It is pivotal to find the differences between the two virus types for scientific, epidemiological, and specific treatment. CAdV-1 (virulent strain) and CAdV-2 (attenuated strain) induced canine hepatitis (ICH) and tracheobronchitis (ITB), respectively, but the clinical symptom is not obvious. CAdV-1 and CAdV-2 have the same genome structure, diameter, morphological features, and cytopathic features, but the same character hinder the diagnose time of the serotypes. CAdV-1 and CAdV-2 have a difference in the genome sequence, coding proteins, viral activity, hemagglutination patterns. After infection, pathogenicity and transmission route are different between the two serotypes. Sequence alignment, PCR, Real time-PCR assay are useful methods to distinguish the two serotypes. The attenuated live CAdV-2 vaccine is currently used to protect against CAdV-1, but it also has a risk. The further research should focus on the pathogenicity mechanism and the useful vaccine for the two serotypes of canine adenovirus.

Integrated Use of Molecular Techniques to Detect and Genetically Characterise DNA Viruses in Italian Wolves (Canis lupus italicus)

Simple Summary

In our study, different quantitative and qualitative molecular techniques were used to detect and genetically characterise Carnivore protoparvovirus 1, Canine adenovirus type 1 and 2 (CAdV-1 and CAdV-2), and Canine circovirus (CanineCV) in Italian wolves (Canis lupus italicus) of the Italian Apennines. Carnivore protoparvoviruses were the most frequently detected viruses, followed by CanineCV and CAdV. All the wolves tested positive for at least one of the DNA viruses screened, and 47.8% of the subjects were coinfected with two or three viruses. From viral sequences analysis, close correlations emerged between the viruses identified in the wolves and those circulating in domestic dogs, suggesting that the same viruses infect wolves and domestic dogs. Further studies are needed to investigate if pathogens are transmitted between the two species.

Abstract

In this study, internal organs (tongue, intestine, and spleen) of 23 free-ranging Italian wolves (Canis lupus italicus) found dead between 2017 and 2019 were tested for Carnivore protoparvovirus 1, Canine adenovirus (CAdV), and Canine circovirus (CanineCV) using real-time PCR assays. Genetic characterisation of the identified viruses was carried out by amplification, sequencing, and analysis of the complete viral genome or informative viral genes. All the wolves tested positive for at least one of the DNA viruses screened, and 11/23 were coinfected. Carnivore protoparvoviruses were the most frequently detected viruses (21/23), followed by CanineCV (11/23) and CAdV (4/23). From the analysis of the partial VP2 gene of 13 carnivore protoparvoviruses, 12 were canine parvovirus type 2b, closely related to the strains detected in dogs and wild carnivores from Italy, and one was a feline panleukopenia-like virus. Of the four CAdV identified, two were CAdV-1 and two were CAdV-2. The complete genome of seven CanineCVs was sequenced and related to the CanineCV identified in dogs, wolves, and foxes worldwide. Close correlations emerged between the viruses identified in wolves and those circulating in domestic dogs. Further studies are needed to investigate if these pathogens may be potentially cross-transmitted between the two species.

Identification of Two Novel Linear Neutralizing Epitopes within the Hexon Protein of Canine Adenovirus Using Monoclonal Antibodies

Canine adenovirus (CAdV) has a high prevalence in canine populations. High affinity neutralizing antibodies against conserved epitopes can provide protective immunity against CAdV and protect against future outbreaks. In this study, we identified two CAdV-2-specific neutralizing monoclonal antibodies (mAbs), 2C1 and 7D7, which recognized two linear-dependent epitopes. MAb 2C1 potently neutralized CAdV-2 with a 50% neutralization titer (NT50) of 4096, and mAb 7D7 partially neutralized CAdV-2 with a 50% NT50 of 64. Immunoprecipitation, Western blot and protein spectral analysis indicated that both neutralizing mAbs recognized the hexon protein (Hex) of CAdV-2. Through a 12-mer random peptide phage display and synthetic peptides analysis, we finely mapped the neutralizing epitopes to two 10-amino acid (aa) peptides within the CAdV Hex: ⁶³⁴RIKQRETPAL⁶⁴³ located on the surface region; and ⁷³⁶PESYKDRMYS⁷⁴⁵ located in the inner region of the expected 3D structure of trimeric Hex. Importantly, the two epitopes are highly conserved among all CAdV isolates by sequence alignment analysis. Thus, these results provide insights into the interaction between virus and mAbs at the aa level and may have potential applications in the development of novel therapeutic or epitope-based vaccines, antibody therapeutics and a diagnostic method suitable for the rapid detection of all CAdVs.

Wolf (Canis lupus) as canine adenovirus type 1 (CAdV-1) sentinel for the endangered cantabrian brown bear (Ursus arctos arctos)

Canine adenovirus type 1 (CAdV-1) causes infectious canine hepatitis (ICH) and has recently been described as a cause of death among endangered populations of European brown bear (Ursus arctos arctos) in the Cantabrian mountain range in Asturias, Spain. Sympatric wild and domestic carnivores can act as reservoirs of the virus and likely spread it into the environment and subsequently transmit it to brown bears. The present work investigates the prevalence and geo-temporal distribution of CAdV-1 among free-ranging wolves (Canis lupus) in Asturias from 2009 to 2018, during which three fatal cases of ICH were reported among brown bears in the region. A total of 149 wolves were analysed in this study, of which 21 (14%) were found to have CAdV-1 DNA based on real-time polymerase chain reaction (RT-PCR) of spleen samples. Prevalence of the virus was similar between males and females. All but one of the 20 CAdV-1-positive animals of estimable age were younger than 2 years, and only one of the 46 adult animals (>2 years) tested positive. Prevalence was highest in the western area of Asturias and during 2010 and 2011. Our results confirm that CAdV-1 is circulating in Asturian free-ranging wolves, supporting their possible role as virus reservoirs and sentinels in the region of this emerging disease in brown bears.

The biological characteristics of the canine adenovirus type 1 from fox and the transcriptome analysis of the infected MDCK cell

Canine adenovirus type 1 (CAdV-1) is the etiologic agent of fox encephalitis, and a virus strain from fox encephalitis is isolated and related research are conducted. In this experiment, the results showed that the F1301 strain was confirmed to be the CAdV-1. The whole genome of the CAdV-1 F1301 strain isolated from fox was 30,535 bp and had higher homology to the other reported CAdV-1 strains. After 0, 12, and 36 h of CAdV-1 infection, the difference gene of the 592 long noncoding RNA and 11,215 microRNA were involved in cell responses to CAdV-1 infection through the PI3K-AKT, Wnt, Herpes simplex, hepatitis C, and Epstein-Barr virus infection pathway in Madin-Darby canine kidney cell line (MDCK). The results indicate that the biological characterization of the CAdV-1 and the MDCK cell-CAdV-1 interaction are clarified.

Novel Genotype Definition and the First Epidemiological Investigation of Canine Adenovirus Type 2 in Dogs in Central China

Infections caused by canine adenovirus (CAdV) type 1 have been reported worldwide in the past two decades. However, only few studies have specifically reported the prevalence of CAdV type 2 (CAdV-2). The present study investigated the persistent circulation of CAdV-2 in dogs with diarrhea in the Henan, Hubei, and Jiangsu provinces in central China from 2017 to 2019. We conducted polymerase chain reaction for detecting CAdV-2 and other related pathogens in 224 rectal swabs of pet dogs and the co-infection of canine diseases was also analyzed. In addition, the structural protein genes-Fiber, Hexon, and Penton-of the isolated CAdV-2 strains were sequenced and analyzed. The similarity between Hexon and Penton among the 19 strains was 97.4%, as revealed by sequence alignment. Multiple sequence alignment results showed that the Fiber gene sequences of these CAdV-2 strains shared 97.4-99.8% nucleotide and 94.1-99.3% amino acid identity with reference sequences and shared only 79.0-80.5% nucleotide and 77.3-80.5% amino acid identity with the vaccine strain CLL, indicating that Fiber harbored most of the variant sites. Furthermore, pairwise sequence comparisons of Hexon of CH-JS-1901 and CH-HN-1801 with that of India2006 revealed a novel genotype. Furthermore, protein model prediction showed that the amino acid mutation of fiber protein in 19 strains was located in the head region, that may cause structural changes on the surface of the fiber protein. These findings are of significance for monitoring the epidemiology of CAdV-2 infection and developing a novel vaccine which contribute to understanding genetic evolution of CAdV-2 in China.

Establishment of a Simple and Efficient Reverse Genetics System for Canine Adenoviruses Using Bacterial Artificial Chromosomes

Canine adenoviruses (CAdVs) are divided into pathotypes CAdV1 and CAdV2, which cause infectious hepatitis and laryngotracheitis in canid animals, respectively. They can be the backbones of viral vectors that could be applied in recombinant vaccines or for gene transfer in dogs and in serologically naïve humans. Although conventional plasmid-based reverse genetics systems can be used to construct CAdV vectors, their large genome size creates technical difficulties in gene cloning and manipulation. In this study, we established an improved reverse genetics system for CAdVs using bacterial artificial chromosomes (BACs), in which genetic modifications can be efficiently and simply made through BAC recombineering. To validate the utility of this system, we used it to generate CAdV2 with the early region 1 gene deleted. This mutant was robustly generated and attenuated in cell culture. The results suggest that our established BAC-based reverse genetics system for CAdVs would be a useful and powerful tool for basic and advanced practical studies with these viruses.

Development of an Immunochromatographic Strip for Rapid Detection of Canine Adenovirus

Although canine adenovirus (CAdV) is highly prevalent in dogs, there is currently a lack of a quick diagnostic method. In this study, we developed a rapid immunochromatographic strip (ICS) assay using colloidal gold coupled to CAdV-2-specific monoclonal antibodies (mAbs). BALB/c mice were immunized with a purified CAdV-2 suspension, and four mAbs (belonging to two different epitopes) were generated and designated as 2C1, 7D7, 10D1, and 4G1. Western blot and protein spectral analysis indicated that the hexon protein of CAdV-2 recognized all four mAbs. The colloidal gold-coupled 7D7 and 2C1 mAbs were chosen for inclusion in the rapid ICS assay. The optimal concentrations of the coating antibody (2C1), the capture antibody (7D7), and the goat anti-mouse antibody were 1.0 mg/ml, 10 μg/ml, and 2.0 mg/ml, respectively. The limit of detection was approximately 2.0 × 10² tissue culture infective dose (TCID₅₀)/ml. Other common canine viruses were tested to evaluate the specificity of the ICS, and positive results were observed for only CAdV-1 and CAdV-2. The ICS test was conducted on 360 samples to detect CAdV, and the results were compared with those of polymerase chain reaction (PCR) tests. The ICS test was found to be a sufficiently sensitive and specific detection method for the convenient and rapid detection of CAdV.

First detection and phylogenetic analysis of porcine circovirus type 2 in raccoon dogs

Background

Porcine circovirus type 2 (PCV2) is a major emerging virus of porcine circovirus-associated disease (PCVAD), which has brought huge economic losses to the global pig industry. Pigs are well known as the natural reservoir of PCV2. Recently, many researchers have revealed PCV2 could infect many other mammals like mice, calves, minks, dogs and goats. In 2018, our laboratory has admitted six cases of raccoon dogs from Qinhuangdao city of China, which were characterized by inappetence, lethargy, depression, abortion, and sterility.

Results

At last, six raccoon dog-origin PCV2 strains were isolated in this study. Pairwise-sequence comparisons demonstrated that the six raccoon dog-origin PCV2 strains shared a nucleotide similarity of 92.1–99.8% among 40 PCV2 representative strains. Phylogenetic analysis indicated these PCV2 isolates belonged to Chinese epidemic genotypes PCV2b and PCV2d. And aborted or sterile symptom was significantly associated with PCV2 infection in raccoon dogs by the chi-square test (χ² = 87.3, p < 0.001). The retrospective study revealed that raccoon dog-origin PCV2 strains shared 100% sequence similarity with the PCV2 stains isolated from pig farms around these raccoon dog farms, respectively.

Conclusion

In this study, the first supported evidence of PCV2 prevalence in raccoon dog farms of China was documented. PCV2 may be one of the most significant causative agents resulting in the reproductive failure of farmed raccoon dogs, implying that PCV2 could transmit from pigs to raccoon dogs. That indicated that PCV2 cross-species transmission will be a serious threat to China’s fur animal farming industry.

First detection and genetic analysis of fox-origin porcine circovirus type 2

Porcine circovirus type 2 (PCV2) is a causative agent of porcine circovirus-associated disease (PCVAD), which is a serious problem in the swine industry worldwide. In recent years, nonporcine-origin PCV2 has attracted more and more attention of the researchers. This study reported on the first identification of PCV2 in farmed foxes with reproductive failure. Three fox-origin PCV2 strains were successfully isolated, sequenced, and designated as FoxHB1, FoxHB2, and FoxHB3 respectively. Pairwise-sequence comparisons of the complete genomes revealed that three fox-origin PCV2 strains had nucleotide identities varied from 91.9% to 99.7% with representative strains of PCV2 different genotypes. Meanwhile, phylogenetic analysis based on complete genomes of 44 PCV2 strains indicated that the fox-origin PCV2 strains belonged to Chinese epidemic genotypes PCV2b and PCV2d. These results provided the first supported evidence that PCV2 could infect foxes, implying that the cross-species transmission of PCV2 would be a big threat to Chinese fur animal-bearing industry.

Sequential circulation of canine adenoviruses 1 and 2 in captive wild carnivores, France

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Two canine adenoviruses (CAdVs) were found to circulate sequentially in captive wild carnivores in France.

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CAdV-1 caused the death of a Eurasian wolf (Canis lupus lupus) with gross lesions and histopathological changes compatible with infectious canine hepatitis.

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CAdV-2 was subsequently found to circulate subclinically in other carnivores of the same zoological park.

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Analysis of the full-length genome of the wolf CAdV-1 strain showed a high genetic relatedness with an Italian strain detected in the same species.

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Future studies are needed to assess the CAdV ecology in endangered wild carnivores.

Scarce data are currently available about the ecology of canine adenoviruses (CAdVs) in wild carnivores. In this paper, the consecutive circulation of CAdV-1 and CAdV-2 in wild carnivores maintained in a French zoological park is reported. A fatal CAdV-1 infection was observed in a Eurasian wolf (Canis lupus lupus), which displayed gross lesions, histopathological changes and immunohistochemical findings suggestive of CAdV-1 infection. The virus was isolated on cell cultures and its genome was determined through next-generation sequencing, resulting genetically related to a recent Italian CAdV-1 strain detected in an Italian wolf. Subsequently, subclinical circulation of CAdV-2 was demonstrated by molecular methods in wild carnivores maintained in the same zoological park, some of which had been previously vaccinated with a CAdV-2 vaccine. Virus detection at a long distance from vaccination and by unvaccinated animals was suggestive of infection by a CAdV-2 field strain, although no data are available about the extent and duration of shedding of CAdV-2 modified-live virus in wild or domestic carnivores. The present paper provides new insights into the CAdV ecology in wildlife, although future studies are needed to fully understand the pathogenic potential of both CAdVs especially in endangered carnivore species.

Novel adenoviruses detected in British mustelids, including a unique Aviadenovirus in the tissues of pine martens (Martes martes)

Several adenoviruses are known to cause severe disease in veterinary species. Recent evidence suggests that canine adenovirus type 1 (CAV-1) persists in the tissues of healthy red foxes (Vulpes vulpes), which may be a source of infection for susceptible species. It was hypothesized that mustelids native to the UK, including pine martens (Martes martes) and Eurasian otters (Lutra lutra), may also be persistently infected with adenoviruses. Based on high-throughput sequencing and additional Sanger sequencing, a novel Aviadenovirus, tentatively named marten adenovirus type 1 (MAdV-1), was detected in pine marten tissues. The detection of an Aviadenovirus in mammalian tissue has not been reported previously. Two mastadenoviruses, tentatively designated marten adenovirus type 2 (MAdV-2) and lutrine adenovirus type 1 (LAdV-1), were also detected in tissues of pine martens and Eurasian otters, respectively. Apparently healthy free-ranging animals may be infected with uncharacterized adenoviruses with possible implications for translocation of wildlife.

SURVEILLANCE FOR ANTIBODIES AGAINST SIX CANINE VIRUSES IN WILD RACCOONS (PROCYON LOTOR) IN JAPAN

Raccoons (Procyon lotor) are found worldwide. They are frequently seen in crowded inner cities as well as in forests or wooded areas, often living in proximity to humans and their pets. We examined sera from 100 wild raccoons in Japan for antibodies to six canine viruses with veterinary significance to assess their potential as reservoirs. We also aimed to understand the distribution of potentially infected wildlife. We found that 7% of samples were seropositive for canine distemper virus (CDV), 10% for canine parvovirus type 2, 2% for canine adenovirus type 1, 6% for canine adenovirus type 2, and 7% for canine coronavirus. No samples were found to be seropositive for canine parainfluenza virus. Seropositivity rates for canine distemper virus and canine parvovirus type 2 were significantly different between areas, and younger raccoons (<1 yr old) were more frequently seropositive than older raccoons. Because raccoons belong to the suborder Caniformia, similar to dogs (Canis lupus familiaris), our results suggest that they can act as reservoirs for some of these important canine viruses and might be involved in viral transmission. Further study should include isolation and analysis of canine viruses in wild raccoons from a wider area.

Novel sequence variants of viral hexon and fibre genes in two dogs with canine adenovirus type 1-associated disease

There is little information on sequence variation of canine adenovirus type 1 (CAdV-1), the aetiological agent of infectious canine hepatitis (ICH). This study reports hexon and fibre gene sequence variants of CAdV-1 in a dog with systemic ICH and a dog with the ocular form of the disease ('blue eye') in Northern Italy in 2013. One of the sequence variants matched a CAdV-1 fox sequence previously detected in Italy.

A Novel Recombinant Canine Adenovirus Type 1 Detected from Acute Lethal Cases of Infectious Canine Hepatitis

In this study, canine adenoviruses (CAdVs) from two acute fatal cases of infectious canine hepatitis (ICH) were analyzed using molecular detection and sequencing of the pVIII, E3, and fiber protein genes. Pathological findings in affected dogs were typical for CAdV-1 associated disease, characterized by severe centrilobular to panlobular necrohemorrhagic hepatitis and the development of disseminated intravascular coagulation in the terminal stages of disease. Comparison of partial genome sequences revealed that although these newly detected viruses mainly had CAdV-1 genome characteristics, their pVIII gene was more similar to that of CAdV-2. This likely suggests that a recombination has occurred between CAdV-1 and CAdV-2, which possibly explains the cause of vaccine failure or increased virulence of the virus in the observed ICH cases.