Role of Protein VII in the Production of Infectious Bovine Adenovirus-3 Virion.

Bovine adenovirus (BAdV)-3 genome encodes a 26 kDa core protein designated as protein VII, which localizes to the nucleus/nucleolus. The requirement of a protein VII-complementing cell line for the replication of VII-deleted BAdV-3 suggests that protein VII is required for the production of infectious progeny virions. An analysis of the BAV.VIId+ virus (only phenotypically positive for protein VII) detected no noticeable differences in the expression and incorporation of viral proteins in the virions. Moreover, protein VII does not appear to be essential for the formation of mature BAV.VIId+. However, protein VII appeared to be required for the efficient assembly of mature BAV.VIId- virions. An analysis of the BAV.VIId- virus (genotypically and phenotypically negative for protein VII) in non-complementing cells detected the inefficient release of virions from endosomes, which affected the expression of viral proteins or DNA replication. Moreover, the absence of protein VII altered the proteolytic cleavage of protein VI of BAV.VIId-. Our results suggest that BAdV-3 protein VII appears to be required for efficient production of mature virions. Moreover, the absence of protein VII produces non-infectious BAdV-3 by altering the release of BAdV-3 from endosomes/vesicles.

A Novel Mastadenovirus from Nyctalus noctula Which Represents a Distinct Evolutionary Branch of Viruses from Bats in Europe.

Bats are natural hosts of a wide variety of viruses, including adenoviruses. European bats are known to carry mastadenoviruses categorized as species B (widespread in European Vespertilionidae bats) and whose taxonomy has not been clarified. We examined fecal samples from Vespertilionidae bats (five species) captured in central Russia and found that 2/12 (16%) were positive for mastadenoviruses. The partial genome of the mastadenovirus was assembled from Pipistrellus nathusii, representing the bat adenovirus species B. The complete genome (37,915 nt) of a novel mastadenovirus was assembled from Nyctalus noctula and named BatAdV/MOW15-Nn19/Quixote. Comparative studies showed significant divergence of the Quixote genome sequence from European bat mastadenoviruses, while the only known virus showing low similarity was the isolate WA3301 from an Australian bat, and together they formed a subclade that separated from other BatAdVs. Phylogenetic and comparative analysis of the protein-coding genes provided evidence that Quixote is related to a novel species within the genus Mastadenovirus, provisionally named "K" (as the next available letter for the species). Phylogenetic analyses revealed that some earlier viruses from Western European bats, for which only partial DNA polymerase genes are known, are most likely members of the tentatively named species "K". Thus, at least two species of mastadenovirus are circulating in bats throughout Europe, from western to eastern areas.

Regions of Bovine Adenovirus-3 Protein VII Involved in Interactions with Viral and Cellular Proteins.

The L 1 region of bovine adenovirus (BAdV)-3 encodes a multifunctional protein named protein VII. Anti-protein VII sera detected a protein of 26 kDa in transfected or BAdV-3-infected cells, which localizes to nucleus and nucleolus of infected/transfected cells. Analysis of mutant protein VII identified four redundant overlapping nuclear/nucleolar localization signals as deletion of all four potential nuclear/nucleolar localization signals localizes protein VII predominantly to the cytoplasm. The nuclear import of protein VII appears to use importin α (α-1), importin-ß (ß-1) and transportin-3 nuclear transport receptors. In addition, different nuclear transport receptors also require part of protein VII outside nuclear localization sequences for efficient interaction. Proteomic analysis of protein complexes purified from recombinant BAdV-3 expressing protein VII containing Strep Tag II identified potential viral and cellular proteins interacting with protein VII. Here, we confirm that protein VII interacts with IVa2 and protein VIII in BAdV-3-infected cells. Moreover, amino acids 91-101 and 126-137, parts of non-conserved region of protein VII, are required for interaction with IVa2 and protein VIII, respectively.

Whole genome analysis of Human Mastadenovirus D causing Keratoconjunctivitis in India - A multicentre study.

INTRODUCTION: Human mastadenovirus (HAdV) types 8, 37, 64 have been considered the major contributors in Epidemic keratoconjunctivitis (EKC) epidemics, but recent surveillance data have shown the involvement of emerging recombinants, including HAdV-53, HAdV-54, and HAdV-56. In our initial work, positive samples for adenovirus revealed that our strains were closer to HAdV-54 than HAdV-8. Hence, the current study aimed to use whole genome technology to identify the HAdV strain correctly. METHODOLOGY: Oxford Nanopore technique was used, wherein a Targeted sequencing approach using long-range PCR amplification was performed. Primers were designed using HAdV-54 (AB448770.2) and HAdV-8 (AB897885.1) as reference sequences. Amplicons were sequenced on the GridION sequencer. Sequences were annotated using Gatu software, and similarities with standard reference sequence was calculated using Bioedit software. The phylogenetic tree was built after alignment in MEGA v7.0 using Neighbour joining method for each of the genes: Penton, Hexon, and Fiber. The effect of novel amino acid changes was evaluated using the PROVEAN tool. The Recombination Detection Program (RDP) package Beta 4.1 was used to identify recombinant sequences. RESULTS: Of the five samples sequenced, OL450401, OL540403, and OL540406 showed nucleotide similarity to HAdV-54 in the penton region. Additionally, OL450401 showed a statistically significant recombination event with HAdV-54 as minor and HAdV-8 as major parents. This was further supported by phylogenetic analysis as well. CONCLUSIONS: In the present study, we have found evidence of a shift from HAdV-8 towards HAdV-54, thus stressing the need for surveillance of HAdVs and to stay updated on the rise of new recombinants.

Ovine adenoviruses infecting sheep and goats in Türkiye: detection and molecular characterization of three different types.

Adenoviruses (AdVs) have been detected in a wide variety of animals. To date, eight types of AdVs in sheep and two types in goats have been identified, which belong to two distinct genera, Mastadenovirus and Atadenovirus. Typically, the term pneumo-enteritis is used to describe adenovirus-induced disease in small ruminants, which has been associated with both enteric and respiratory symptoms of varying severity. The aim of this study was to detect and identify AdVs of small ruminants belonging to the genera Mastadenovirus and Atadenovirus. For this purpose, diagnostic samples (47 lung, 27 intestine, and two pooled tissue samples including intestine and lung) from 49 small ruminants (39 sheep and 10 goats) were used. Following the viral DNA extraction, PCR was carried out by using the primers targeting the hexon gene in order to detect both mast- and atadenoviruses. Sequencing the amplified fragments revealed the presence of three types of ovine adenovirus (OAdV): OAdV-3, OAdV-4, and OAdV-8. Specifically, OAdV-3 was detected in two sheep and a goat while OAdV-4 and OAdV-8 were found in only one sheep each. There is still limited data on the interaction between the viruses in different adenovirus genera and the detected disease, as well as the genetic diversity of adenoviruses, especially in small ruminants. In conclusion, the detection of AdVs in lung and intestinal tissues of small ruminants in this study suggests that these viruses may have contributed to the disease and/or predisposed to other agents.

Evaluation of Mastadenovirus and Rotavirus Presence in Phyllostomid, Vespertilionid, and Molossid Bats Captured in Rio Grande do Sul, Southern Brazil.

Bat-borne viruses may affect public health and the global economy. These mammals have a wide geographical distribution and unique biological, physiological, and immunogenic characteristics, allowing the dissemination of many known and unknown viruses. Enteric viruses, such as adeno (AdV) and rotaviruses, are recognized as the main causative agents of disease and outbreaks. In the present study, the presence of viruses from Adenoviridae and Reoviridae families was evaluated in molossid, phyllostomid, and vespertilionid bats captured in Rio Grande do Sul, Southern Brazil, between September 2021 and July 2022. Sixty bat rectal swabs were analyzed by PCR. Eight (13.3%) samples were positive for adenovirus and classified as human mastadenovirus C (HAdV-C) (three samples) and HAdV-E (five samples) by sequencing followed by phylogenetic analysis. All samples were negative in rotavirus specific RT-PCR. This is the first study to describe the presence of HAdV in samples of Glossophaga soricina, Eptesicus brasiliensis, and Histiotus velatus. Furthermore, the presence of HAdV-E in bats was reported, which is unusual and may suggest that other HAdV genotypes, in addition to HAdV-C, may also be harbored by wild animals. The data generated in the present study reinforces the importance of eco-surveillance of viral agents related to diseases in humans and wild animals. In addition, it is essential to identify possible new hosts or reservoirs that increase the risk of spillover and dissemination of infectious pathogens, helping to prevent and control zoonotic diseases.

Genomic Expedition: Deciphering Human Adenovirus Strains from the 2023 Outbreak in West Bengal, India: Insights into Viral Evolution and Molecular Epidemiology.

Understanding the genetic dynamics of circulating Human Adenovirus (HAdV) types is pivotal for effectively managing outbreaks and devising targeted interventions. During the West Bengal outbreak of 2022-2023, an investigation into the genetic characteristics and outbreak potential of circulating HAdV types was conducted. Twenty-four randomly selected samples underwent whole-genome sequencing. Analysis revealed a prevalent recombinant strain, merging type 3 and type 7 of human mastadenovirus B1 (HAd-B1) species, indicating the emergence of recent strains of species B in India. Furthermore, distinctions in VA-RNAs and the E3 region suggested that current circulating strains of human mastadenovirus B1 (HAd-B1) possess the capacity to evade host immunity, endure longer within hosts, and cause severe respiratory infections. This study underscores the significance of evaluating the complete genome sequence of HAdV isolates to glean insights into their outbreak potential and the severity of associated illnesses.

Genetic diversity of adenovirus in neotropical bats from Brazil.

Bats can harbor a diversity of viruses, such as adenovirus. Ten different species of bat adenoviruses (BtAdV A to J) have been previous described worlwide. In Brazil, BtAdV was described in three species of phyllostomid species: Artibeus lituratus, Desmodus rotundus, and Sturnira lilium. There are around 180 bat species in Brazil, with 67% inhabiting the Atlantic Forest, with few information about the circulation of BtAdV in this biome. We aimed to describe the molecular detection and the phylogenetic characterization and suggest a classification of BtAdVs circulating in bats from the Brazilian Atlantic Forest. We collected 382 oral and rectal swabs from 208 bats between 2014-2015 and 2020-2021 from São Paulo, Pernambuco, and Santa Catarina Brazilian states. The adenovirus detection was done by a nested PCR targeting the DNA polymerase gene, and all positive samples were sequenced by the Sanger method. The phylogenetic analyses were based on the amino acid sequences using the MEGA 7 and BEAST software. We obtained 16 positive animals (detection rate 7.7%) belonging to seven bat species: Artibeus lituratus, Carollia perspicillata, Sturnira lilium, Molossus molossus, and the first record of Phyllostomus discolor, Eptesicus diminutus, and Myotis riparius. The phylogenetic analysis based on partial amino acid sequences showed that all obtained AdV sequences belong to the Mastadenovirus genus. We observed a high genetic diversity of BtAdV and identified eleven potential BtAdV species circulating in Brazil (BtAdV K to U). Our results contribute to the epidemiological surveillance of adenovirus, increasing the knowledge about the viral diversity and the distribution of AdV in bats from the Atlantic Forest.

Deer mastadenovirus B pneumonia in a white-tailed deer fawn.

A 7-mo-old farmed white-tailed deer fawn (Odocoileus virginianus) died after several weeks of progressive deterioration associated with endoparasitism and respiratory signs. A field autopsy was performed, and lung tissue was submitted for histologic examination. The findings were consistent with necrosuppurative bronchointerstitial pneumonia with intranuclear viral inclusions. Immunofluorescence using fluorescently labeled polyclonal antibodies to bovine adenovirus 3 and 5 was positive. To rule out cross-reactivity with other adenoviruses, formalin-fixed, paraffin-embedded tissue sections were submitted for genome sequence analysis, which revealed a 99.6% match to Deer mastadenovirus B (formerly Odocoileus adenovirus 2, OdAdV2). To our knowledge, natural clinical disease associated with OdAdV2 has not been reported previously.

Detection and Phylogenetic Characterization of a Novel Adenovirus Found in Lesser Mouse-Eared Bat (Myotis blythii) in South Kazakhstan.

Bats are an important natural reservoir of various pathogenic microorganisms, and regular monitoring is necessary to track the situation of zoonotic infections. When examining samples from bats in South Kazakhstan, nucleotide sequences of putative novel bat adenovirus (AdV) species were found. Estimates of amino acid identities of the hexon protein have shown that potentially novel Bat mastadenovirus BatAdV-KZ01 shared higher similarity with monkey Rhesus adenovirus 59 (74.29%) than with Bat AdVs E and H (74.00%). Phylogenetically, BatAdV-KZ01 formed a separate clade, distant from Bat AdVs and other mammalian AdVs. Since adenoviruses are essential pathogens for many mammals, including humans and bats, this finding is of interest from both scientific and epidemiological points of view.

Characterization of monkey adenoviruses with three fiber genes.

Although the occurrence of three fiber genes in monkey adenoviruses had already been described, the relatedness of the "extra" fibers have not yet been discussed. Here we report the genome analysis of two simian adenovirus (SAdV) serotypes from Old World monkeys and the phylogenetic analysis of the multiple fiber genes found in these and related AdVs. One of the newly sequenced serotypes (SAdV-2), isolated from a rhesus macaque (Macaca mulatta), was classified into species Human mastadenovirus G (HAdV-G), while the other serotype (SAdV-17), originating from a grivet (Chlorocebus aethiops), classified to Simian mastadenovirus F (SAdV-F). We identified unique features in the gene content of these SAdVs compared to those typical for other members of the genus Mastadenovirus. Namely, in the E1B region of SAdV-2, the 19K gene was replaced by an ITR repetition and a copy of the E4 ORF1 gene. Among the 37 genes in both SAdVs, three genes of different lengths, predicted to code for the cellular attachment proteins (the fibers), were found. These proteins exhibit high diversity. Yet, phylogenetic calculations of their conserved parts could reveal the probable evolutionary steps leading to the multiple-fibered contemporary HAdV and SAdV species. Seemingly, there existed (a) common ancestor(s) with two fiber genes for the lineages of the AdVs in species SAdV-B, -E, -F and HAdV-F, alongside a double-fibered ancestor for today's SAdV-C and HAdV-G, which later diverged into descendants forming today's species. Additionally, some HAdV-G members picked up a third fiber gene either to the left-hand or to the in-between position from the existing two. A SAdV-F progenitor also obtained a third copy to the middle, as observed in SAdV-17. The existence of three fiber genes in these contemporary AdVs brings novel possibilities for the design of optimised AdV-based vectors with potential multiple target binding abilities.

First DNA sequence proof for the occurrence of bovine adenovirus types 10 and 11 in continental Europe.

Bovine adenoviruses (BAdV) are known to cause respiratory and/or intestinal disease in calves. Infection can manifest as acute outbreaks, but more often only sporadic cases occur. Here we describe the PCR detection and partial sequence characterization of several BAdVs found in sick or dead calves on different farms in Western Hungary. Intermittent diarrhoeal illnesses occurred after weaning among calves on several farms located up to 40 km apart. A high-sensitivity, broad-spectrum nested PCR, developed for the general detection of adenoviruses, gave positive results in four independent cases. Direct sequencing of PCR products showed clear results from only two samples, whereas sequences from the other two amplicons were mixed. Molecular cloning of these heterogeneous PCR products was performed to separate each DNA fragment therein. By sequencing several plasmid clones from both mixed samples, we were able to detect the simultaneous presence of two different BAdV types, namely types 6 and 10 classified into two separate (Atadenovirus and Mastadenovirus) genera. The sequence of one homogenous sample was identified as being derived also from BAdV-10, whereas the other sample contained a novel type, proposed to be BAdV-11. We demonstrated, for the very first time, the occurrence of the two latter virus types in continental Europe. Their appearance in Hungary marks a significant shift in the types of BAdVs actually circulating in the country. Considering the similarity of the pathological findings to those, attributed to BAdV-10 infections reported to date, the causative role of the viruses in these cases seems to be plausible. Phylogeny reconstruction further confirmed that BAdVs represent multiple genetic lineages.

Detection of human Mastadenovirus C in wild guinea pigs (Cavia aperea aperea) feces.

The Adenoviridae family is composed by a high diversity of viruses that are extremely resistant in environment and are frequently excreted in animal reservoir feces for long periods. The knowledge of adenovirus (AdV) diversity among wild species may be important for the understanding of the epidemiology of putative emerging diseases. Cavia aperea aperea, commonly known as wild guinea pigs, wild cavies, or preas, are small herbivorous rodents widely distributed throughout South America and classified in Caviidae family, as well as domestic guinea pigs and capybaras. In order to investigate their potential role as reservoir of zoonotic agents, the present study aimed to verify the presence of AdV in fecal samples of 14 preas from Northeast Brazil. When submitted to nested PCR, two out of 14 samples (14.28%) were positive for AdV and classified as human Mastadenovirus C (HAdV-C) using DNA sequencing and phylogenetic analysis. Wild guinea pigs are synanthropic rodents that live in close contact with humans. The investigation of viral agents in rodents is important due to their potential role as reservoirs of human and animal pathogens. Moreover, the present work presents the first known evidence of HAdV in wild guinea pig stool samples, which may represent both the impact of anthropogenic pollution to wild animals and an important knowledge in terms of human health.

Genome Analyses of Ten New Ape Adenoviruses with Similarity to Human Mastadenovirus C.

The adenoviruses (AdVs) isolated from humans are taxonomically grouped in seven different species in the Mastadenovirus genus (HAdV-A through G). AdVs isolated from apes are often included in one of the human AdV species. Here we describe the sequence analyses of ten new AdVs that are related to the HAdV-C species and that were isolated from healthy western lowland gorillas, bonobos, chimpanzees, and orangutans kept in Dutch zoos. We analyzed these viruses and compared their genome sequences to those of human- and ape-derived AdV sequences in the NCBI GenBank database. Our data demonstrated that the ape-derived viruses clustering to HAdV-C are markedly distinct from the human HAdV-C species in the size and nucleotide composition (%GC) of their genome, differ in the amino-acid sequence of AdV proteins, and have longer RGD-loops in their penton-base proteins. The viruses form three well-separated clades (the human, the gorilla, and the combined group of the bonobo and chimpanzee viruses), and we propose that these should each be given species-level ranks. The Ad-lumc005 AdV isolated from orangutans was found to be very similar to the gorilla AdVs, and bootstrap inference provided evidence of recombination between the orangutan AdV and the gorilla AdVs. This suggests that this virus may not be a genuine orangutan AdV but may have been transferred from a gorilla to an orangutan host.

Host diversification is concurrent with linear motif evolution in a Mastadenovirus hub protein.

Over one hundred Mastadenovirus types infect seven orders of mammals. Virus-host coevolution may involve cospeciation, duplication, host switch and partial extinction events. We reconstruct Mastadenovirus diversification, finding that while cospeciation is dominant, the other three events are also common in Mastadenovirus evolution. Linear motifs are fast-evolving protein functional elements and key mediators of virus-host interactions, thus likely to partake in adaptive viral evolution. We study the evolution of eleven linear motifs in the Mastadenovirus E1A protein, a hub of virus-host protein-protein interactions, in the context of host diversification. The reconstruction of linear motif gain and loss events shows fast linear motif turnover, corresponding a virus-host protein-protein interaction turnover orders of magnitude faster than in model host proteomes. Evolution of E1A linear motifs is coupled, indicating functional coordination at the protein scale, yet presents motif-specific patterns suggestive of convergent evolution. We report a pervasive association between Mastadenovirus host diversification events and the evolution of E1A linear motifs. Eight of 17 host switches associate with the gain of one linear motif and the loss of four different linear motifs, while five of nine partial extinctions associate with the loss of one linear motif. The specific changes in E1A linear motifs during a host switch or a partial extinction suggest that changes in the host molecular environment lead to modulation of the interactions with the retinoblastoma protein and host transcriptional regulators. Altogether, changes in the linear motif repertoire of a viral hub protein are associated with adaptive evolution events during Mastadenovirus evolution.

Sensitivity of Human Mastadenovirus, the Causal Agent of Pharyngoconjunctival Fever, Epidemic Keratoconjunctivitis, and Hemorrhagic Cystitis in Immunocompromised Individuals, to Brincidofovir.

Human mastadenovirus (HAdV), a linear double-stranded DNA (dsDNA) virus, is the causal agent of several diseases, including pharyngoconjunctival fever, epidemic keratoconjunctivitis, and hemorrhagic cystitis, in immunocompromised individuals. There are more than 100 reported types of adenoviruses, but the pathogenicity of many HAdVs remains unknown. Brincidofovir (BCV) is a hexadecyloxypropyl lipid conjugate of cidofovir (CDV) that is active against dsDNA viruses. Clinical effectiveness of BCV against certain HAdV species has been reported; however, its activity against novel HAdV types remains unknown. We investigated the half-maximal inhibitory concentration (IC50) values of BCV for novel HAdV types and found that the epidemic keratoconjunctivitis-associated HAdV-D54 prevalent in the Asian region was the most susceptible. The mean overall IC50 value of BCV was lower than that of CDV, indicating that BCV is effective against HAdVs, including the novel types. IMPORTANCE We investigated the IC50 values of BCV for novel HAdV types and found that the epidemic keratoconjunctivitis-associated HAdV-D54 prevalent in the Asian region was the most susceptible. In addition, the mean overall IC50 value of BCV was lower than that of CDV, indicating that BCV is effective against HAdVs.

Complete genome sequence of a novel bat mastadenovirus C strain isolated from Rhinolophus cornutus in Japan.

Here, we report a novel bat adenovirus strain isolated from apparently healthy bats of the species Rhinolophus cornutus in Japan. The genome of the isolate was 36,506 bp in length and encoded at least 33 proteins. Phylogenetic analysis of the DNA polymerase amino acid sequence, which provides one demarcation criterion for adenoviral species, indicated that the isolate belongs to the species Bat mastadenovirus C in the genus Mastadenovirus. Most of the encoded proteins shared high sequence similarity with those of known bat adenovirus C strains detected in different species of Rhinolophus, whereas the fiber protein and some E3- and E4-related proteins shared moderate similarity, and only the large E3 protein, which contains several host immune-suppression-related motifs, showed considerably lower similarity.

Genomic characteristics and pathogenicity of a new bat adenoviruses strains that was isolated in at sites along the southeastern coasts of the P. R. of China from 2015 to 2019.

Bats are important reservoirs for many kinds of emerging zoonotic viruses. In order to explore potential pathogens carried by bats and trace the source of adenovirus outbreaks on the southeastern coast of China, we took pharyngeal and anal swabs from a total of 552 bats (Rhinolophus pusillus) collected from various areas of Chinese southeastern coast. Adenoviruses were identified in 36 out of the 552 samples (6.5%) . Complete genome sequences of two adenovirus isolations from Vero E6 cells were obtained, which were further validated as identical strains via next-generation sequencing and were named Bat-Advcxc6. The cell culture inoculated with the two samples exhibited remarkable cytopathic changes. The full genome has 37,315 bp and owns 29 open reading frames. Phylogenetic analyses confirmed that Bat-Advcxc6 represented a novel bat adenovirus species in the genus Mastadenovirus. Transmission electron microgram showed clear virus particles. Bat-Advcxc6 shared similar characteristics of G + C contents with Bat mastadenovirus WIV11 (Bat mastadenovirus C) found in China in 2016, but differed from this serotype due to a <75% similarity with DNA polymerase amino acid sequences in WIV11. As it is a newly found adenovirus strain according to the international classification criteria, further analyses of virus dynamics, epithelial invasion, and immunization assays are required to explore its potential threats of cross-species transmission.

First Report on Detection and Molecular Characterization of Adenoviruses in the Small Indian Mongoose (Urva auropunctata).

Using a broad-range nested PCR assay targeting the DNA-dependent DNA polymerase (pol) gene, we detected adenoviruses in 17 (20.48%) out of 83 fecal samples from small Indian mongooses (Urva auropunctata) on the Caribbean island of St. Kitts. All 17 PCR amplicons were sequenced for the partial pol gene (~300 bp, hereafter referred to as Mon sequences). Fourteen of the 17 Mon sequences shared maximum homology (98.3-99.6% and 97-98.9% nucleotide (nt) and deduced amino acid (aa) sequence identities, respectively) with that of bovine adenovirus-6 (species Bovine atadenovirus E). Mongoose-associated adenovirus Mon-39 was most closely related (absolute nt and deduced aa identities) to an atadenovirus from a tropical screech owl. Mon-66 shared maximum nt and deduced aa identities of 69% and 71.4% with those of atadenoviruses from a spur-thighed tortoise and a brown anole lizard, respectively. Phylogenetically, Mon-39 and Mon-66 clustered within clades that were predominated by atadenoviruses from reptiles, indicating a reptilian origin of these viruses. Only a single mongoose-associated adenovirus, Mon-34, was related to the genus Mastadenovirus. However, phylogenetically, Mon-34 formed an isolated branch, distinct from other mastadenoviruses. Since the fecal samples were collected from apparently healthy mongooses, we could not determine whether the mongoose-associated adenoviruses infected the host. On the other hand, the phylogenetic clustering patterns of the mongoose-associated atadenoviruses pointed more towards a dietary origin of these viruses. Although the present study was based on partial pol sequences (~90 aa), sequence identities and phylogenetic analysis suggested that Mon-34, Mon-39, and Mon-66 might represent novel adenoviruses. To our knowledge, this is the first report on the detection and molecular characterization of adenoviruses from the mongoose.

A potential bat adenovirus-based oncolytic virus targeting canine cancers.

Although a canine adenovirus (CAdV)-based oncolytic virus (OV) candidate targeting canine tumors has been reported, its oncolytic effect could be attenuated by CAdV vaccine-induced neutralizing antibodies in dog patients. To circumvent this issue, we focused on the bat adenovirus (BtAdV) strain, which was previously isolated from healthy microbats. We previously showed that this virus replicated efficiently in canine cell lines and did not serologically cross-react with CAdVs, suggesting that it may offer the possibility of an OV candidate for canine tumors. Here, we tested the growth properties and cytotoxicity of the BtAdV Mm32 strain in a panel of canine tumor cells and found that its characteristics were equivalent to those of CAdVs. To produce an Mm32 construct with enhanced tumor specificity, we established a novel reverse genetics system for BtAdV based on bacterial artificial chromosomes, and generated a recombinant virus, Mm32-E1Ap + cTERTp, by inserting a tumor-specific canine telomerase reverse transcriptase promoter into its E1A regulatory region. The growth and cytotoxicity of this recombinant were superior to those of wild-type Mm32 in canine tumor cells, unlike in normal canine cells. These data suggest that Mm32-E1Ap + cTERTp could be a promising OV for alternative canine cancer therapies.