Phylogenetic analysis of papillomaviruses in dogs from southern Brazil: molecular epidemiology and investigation of mixed infections and spillover events

Papillomaviruses (PVs) have been identified in several animal species, including dogs (canine papillomaviruses, CPVs) and cattle (bovine papillomaviruses, BPVs). Although some BPVs may occasionally infect species other than cattle, to the best of our knowledge, BPVs have not been reported in dogs to date. Herein, we carried out a retrospective phylogenetic study of PVs circulating in dogs from southern Brazil between 2017 and 2022, also investigating possible mixed infections and spillover events. For this, we screened 32 canine papilloma samples by PCR using the degenerate primers FAP59/64 and/or MY09/11, which amplify different regions of the L1 gene; the genomic target often used for PV classification/typing. Out these, 23 PV DNA samples were successfully amplified and sequenced. All PVs amplified by FAP59/64 (n = 22) were classified as CPV-1. On the other hand, PVs amplified by MY09/11 (n = 4) were classified as putative BPV-1. Among these, three samples showed mixed infection by CPV-1 and putative BPV-1. One of the putative BPV-1 detected in co-infected samples had the L1 gene full-sequenced, confirming the gene identity. Furthermore, the phylogenetic classifications from the FAP59/64 and/or MY09/11 amplicons were supported by a careful in silico analysis, which demonstrated that the analysis based on them matches to the classification from the complete L1 gene. Overall, we described CPV-1 circulation in southern Brazil over the years and the potencial BPV infection in dogs (potential spillover event), as well as possible CPV/1/BPV-1 co-infections. Finally, we suggest the analysis of the complete genome of the putative BPVs detected in dogs in order to deepen the knowledge about the PV-host interactions.

Diagnosis and phylogenetic analysis of bovine papillomaviruses in cattle papillomatosis cases by different methods

Papillomaviruses, known as epitheliotropic, cause proliferation in the skin, mucosa, and different visceral organs. In this study, it was aimed to diagnose bovine papillomavirus (BPV) by using different methods in the lesion taken from twenty cattle with papillomas in different areas of the body and to reveal its molecular characterization. In our study, molecular, immunohistochemistry, and transmission electron microscopy (TEM) methods were used for virus identification. Additionally, sequencing analysis was used to ascertain the phylogenetic relationship between the obtained field strains and other isolates submitted to GenBank. Histopathological analyses of the collected samples were done in addition to diagnostic procedures. Intranuclear virus particles were detected when the papillomas were investigated with TEM. In PCR analyses using degenerate and type-specific primer sets, the presence of BPV nucleic acid was determined in 70% (14/20) and 90% (18/20) of the samples, respectively. No virus could be detected in PCR applications using MY 09/11 degenerate primer sets. Twenty animals of different ages, races, and genders included in the study by random sampling method from different herds were divided into 4 groups according to the body regions where the lesions were located. Sequence analysis was performed on a sample from each group that showed strong positivity in the PCR technique using FAP 59/64 degenerate primer set and type-specific primer set. Sequence analyses were performed using FAP 59/64 degenerate primers of amplicons for phylogenetic research. In these analyses, three of the isolated strains were identified as BPV-1, which is in the Deltapapillomavirus 4 genus, and one as BPV-2. As a result of the study, it was concluded that molecular and phylogenetic studies using type-specific primers are more beneficial in order to fully reveal the etiology of papillomatosis in cattle and it would be correct to determine BPV types before prophylactic (vaccine, etc.) applications.

Genotypes and morphologies of bovine papillomaviruses in Costa Rica

Bovine papillomaviruses (BPVs) infect the basal layer of the epithelium of bovines, where they persist asymptomatically or produce benign fibroepithelial hyperplasia in the skin or mucosa. The aim of the present study was to describe the genotypes of bovine papillomas at the macroscopic and microscopic level. A descriptive study was carried out using non-probabilistic convenience sampling. Ninety-nine papillomas from 63 animals were collected on 32 farms, as well as information about age, gender, breed, and productive use of the bovines. The location, type, and degree of epithelial invasion of the papillomas were recorded. The samples were subjected to molecular and histopathological analysis. Papillomas were found most frequently on dairy farms (75.0%), in females (95.0%), in cattle of the Holstein breed (45.0%), and in animals over 24 months of age (50.0%). Most of the positive animals had from 1 to 15 papillomas (31.6%) and only one type of papilloma (79.4%). Cauliflower-like papillomas were found in 48.5% of the cases, while atypical papillomas were found in 11.1% of the cases. Cauliflower-like papillomas were found mainly on the udder (14.4%), head (10.0%), and neck (10.0%) and were associated with five BPV genotypes (BPV1, BPV2, BPV6, BPV7, and BPV10), while BPV2 and BPV6 were found to be associated with all types of papillomas (cauliflower, flat, pedunculated, and atypical). The presence of BPV11 in flat papillomas and BPV6 in atypical papillomas is reported here for the first time. Morphology and histopathological findings did not allow differentiation of the BPV genotypes.

Phylogeny and amino acid analysis in single and mixed bovine papillomavirus infections in Southern Brazil, 2016-2020

Bovine papillomaviruses (BPVs) exhibit a high degree of genetic variability, and several viral types have been identified based on analysis of the L1 gene. The L1 is the main capsid protein and the main target for neutralizing antibodies. We performed a retrospective study on BPVs circulating in Rio Grande do Sul state, Southern Brazil, in 2016-2020. DNA from 43 bovine papilloma samples were amplified using two degenerate primer sets - FAP59/64 and MY09/11 - targeting the L1 region, and analyzed for phylogeny, mixed BPV infections (coinfections) and amino acid (aa) sequences. We also performed an in silico analysis with 114 BPV L1 sequences from the GenBank database to assess the agreement between the phylogeny obtained based on complete L1 sequences versus that based on the region amplified using the FAP59/64 and MY09/11 primer sets. Considering single and coinfections, we identified 31 BPV-1 (31/43; 72.1%), 27 BPV-2 (27/43; 62.8%) and 4 BPV-6 (4/43; 9.3%). Coinfections with BPV-1 and BPV-2 were observed in 61.3% of the samples. Our results are supported by in silico analyses that demonstrate that the classification using FAP59/64 or MY09/11 matches the complete L1 results, except for BPV-17 and -18, which may be mistakenly classified depending on the primers used. Furthermore, we found unique or rare amino acids in at least one L1 sequence of each BPV type identified in our study, some of which have been identified previously in papillomavirus epitopes, suggesting immune-mediated selection. Finally, our study provides an overview of BPVs circulating in Southern Brazil over the last five years and point to the combined use of primers FAP59/64 and MY09/11 for analysis of BPV coinfections and putative epitopes.

Detection of Equus caballus papillomavirus-2 in equine penile/preputial papillomas and squamous cell carcinomas in southern Brazil

For approximately one decade, a novel papillomavirus termed Equus caballus papillomavirus-2 (EcPV-2) has been associated with equine penile/preputial papillomas and squamous cell carcinomas (SCCs). It is currently believed that the virus has a carcinogenic activity, being able to induce such neoplastic lesions. After being first described, EcPV-2 has been detected in many countries from North America, Europe, and Asia; however, to date, it has not been reported in Brazil. The aim of this research was to investigate the presence of EcPV-2 in penile/preputial papillomas and SCCs of Brazilian horses. Forty samples diagnosed as equine penile and/or preputial papillomas, carcinomas in situ (CIS), or SCCs in two veterinary anatomic pathology services from southern Brazil were investigated. Histologic evaluation and immunohistochemistry (IHC) using a BPV-1 antibody were performed. Posteriorly, the samples were submitted to polymerase chain reaction using two broad-spectrum (MY09/11 and FAP) and one EcPV-2-specific primer sets. Positive samples were sequenced. PV antigen expression was detected in one papilloma, one CIS, and two SCCs by IHC. Five SCCs, one papilloma, and one CIS were PV-positive on PCR. Sequencing of the seven PCR products revealed homology with EcPV-2. This study confirms the occurrence of EcPV-2 infection in Brazilian horses. Moreover, the results presented here provide useful information concerning the phylogeny from the viruses detected in our samples. We hope to encourage further studies on this novel agent, contributing to its characterization, and, possibly, to the eventual development of preventive measurements, including a possible vaccine.

Metatranscriptomics Analysis Reveals Diverse Viral RNA in Cutaneous Papillomatous Lesions of Cattle

Bovine papillomavirus (BPV) is associated with bovine papillomatosis, a disease that forms benign warts in epithelial tissues, as well as malignant lesions. Previous studies have detected a co-infection between BPV and other viruses, making it likely that these co-infections could influence disease progression. Therefore, this study aimed to identify and annotate viral genes in cutaneous papillomatous lesions of cattle. Sequences were obtained from the GEO database, and an RNA-seq computational pipeline was used to analyze 3 libraries from bovine papillomatous lesions. In total, 25 viral families were identified, including Poxviridae, Retroviridae, and Herpesviridae. All libraries shared similarities in the viruses and genes found. The viral genes shared similarities with BPV genes, especially for functions as virion entry pathway, malignant progression by apoptosis suppression and immune system control. Therefore, this study presents relevant data extending the current knowledge regarding the viral microbiome in BPV lesions and how other viruses could affect this disease.

Electron microscopy and phylogenetic analysis of Bovine papillomavirus infection in cattle from four Egyptian governorates

Cutaneous warts are the common clinical feature of infection with Bovine papillomavirus (BPV), and it is commonly known as bovine papillomatosis. It causes significant economic losses, especially in the dairy sector. The aim of this study was surveillance of the circulating strains of BPV in four Egyptian governorates and characterization by electron microscopy. Warts skin lesions and whole blood from seventy-eight native breed cattle were obtained. Molecular detection using two different sets of primers, phylogenetic analysis, and electron microscopy were carried out. The obtained results showed that using FAP59/FAP64 primer set is more sensitive than the MY09/My11 primer set in the detection of the papilloma L1 gene either in the blood or in the skin lesion. Sequence analysis of the partially amplified L1 gene revealed 4 different strains belonging to Deltapapillomavirus 4. Only Alfayoum_Deltapapillomavirus_2018 (accession no: MW018705) was found to be closely related to the strain previously isolated in different Egyptian governorates in 2017, and 2 strains were closely related to an isolate of equine origin. Electron microscopy examination of the skin lesions showed the presence of negatively stained rounded, non-enveloped virus particles with a size of 60 nm in diameter. In conclusion, continuous surveillance and characterization of the circulating strains using multiple sets of primers are important. Efficient biosecurity measures must be applied to decrease transmission of papillomavirus between the different animal species, especially in the mixed management system.

Clinicopathological characteristics and papillomavirus types in cutaneous warts in bovine

Thirty-one bovine cutaneous warts were submitted to macroscopic and histological analyses and to molecular analyses to partial amplification and sequencing of the L1 gene of bovine papillomavirus (BPV). Viral types detected were BPV1 (52%), BPV2 (29%), BPV6 (16%) and BPV10 (3%). BPV2 had lower frequency in papilloma in comparison to that in fibropapilloma (p = 0.002).

Molecular detection and immunopathological examination of Deltapapillomavirus 4 in skin and udder of Egyptian cattle

Aim

Bovine papillomaviruses (BPVs) are the main cause of bovine papillomatosis resulting in cutaneous and/or mucosal benign tumors that could be transformed to malignant ones with marked economic importance, especially in the dairy farms. Molecular, pathological, and immunohistochemical (IHC) diagnosis of bovine papillomatosis cases was conducted to identify and characterize the circulating BPV genotype in some Egyptian governorates.

Materials and Methods

Wart-like lesions in skin, udder, and teats were collected from 123 infected cases in Giza, Beni Suef, and El Menoufia Governorates, Egypt, during 2016-2017. Pathological and IHC characterization, molecular identification, genotyping, and phylogenetic analysis based on the conserved late (L1) gene of the all samples were carried out.

Results

89 of the 123 collected samples (72.3%) were positively detected by polymerase chain reaction (PCR). The sequence analysis of the obtained PCR amplicons was identical revealing identification and genotyping of only one type (Deltapapillomavirus 4 isolate EGY 2017) with accession number (MG547343) which found to be closely related to the recently detected Deltapapillomavirus 4 isolate 04_asi_UK (accession no. MF384288.1) and isolate Deltapapillomavirus 4 isolate 25_equ_CH (accession no. MF384286.1) with 99% nucleotide sequence identity. Histopathological examination revealed severe hyperkeratosis in stratum corneum and acanthosis in most of the cases. These tissue changes were confirmed by the presence of golden brown stained proliferating cell nuclear antigen which was localized intranuclear and perinuclear in other cells using IHC Technique.

Conclusion

It is the first time to detect and genotype the BPVs in these areas with no record of previous genotyping in the whole country. The obtained results will highlight the importance of this disease.

A teat papillomatosis case in a Damascus goat (Shami goat) in Hatay province, Turkey: a new putative papillomavirus?

Papillomaviruses (PVs) are epitheliotropic viruses that cause benign proliferative lesions in the skin (warts or papillomas) and mucous membranes of their natural hosts. Recently, new PVs have been found in many animal species. The most common current approach for identifying novel PV types is based on PCR, using various consensus or degenerated primer (broad-range primers), designed on the basis of the multiple alignment of nucleotide or amino acid sequences of a large number of different human papillomaviruses (HPV). PVs have been classified according to the sequence similarity of one of their capsid proteins, L1, without taking into account other regions of the genome and without considering the phenotypic characteristics of the viral infection. In this study, we performed molecular detection and typing of a PV in a goat with teat papillomatosis. Firstly, PCR was performed using the FAP59/FAP64 and MY09/MY11 primer pairs for the L1 gene region. The PV DNA was found to be positive only with the FAP59/FAP64 primer pair. PV DNA was then tested with three primer sets in four different combinations (L2Bf/FAP64, L2Bf/L1Br, FAP59/FAP64, L1Bf/LCRBr) for the gene region encoding the L1, L2 and LCR proteins. The goat teat papilloma sample was amplified using FAP59/FAP64 primers and two primer pairs (L2Bf/FAP64 and L2Bf/L1Br). We obtained products matching approximately 604 bp of the L1 region of the virus. PV DNA was used for typing using sequence analysis/PCR with some type-specific primers for bovids, caprids and cervids. The results of the sequence analysis suggested one new putative PV type with sequence identity ranging from 46.45 to 80.09% to other known papillomaviruses, including Capra hircus papillomavirus (ChPV-2), bovine papillomavirus (BPV) 6, 7, 10, 11 and 12, Rangifer tarandus papillomavirus 3 (RtPV-3) and BPV-7Z (Alpine wild ruminant papillomavirus; Cervus elaphus papillomavirus). We therefore propose that this is the first identification of a new putative type, MG523274 (HTY-goat-TR2016), in a goat with teat papillomatosis. It is essential to identify PV types in different animal species and investigate their prevalence/distribution and clinical consequences in order to develop appropriate prophylactic and/or therapeutic procedures and to determine the interspecies transmission potential and evolution of PVs.

The genetic diversity of bovine papillomaviruses (BPV) from different papillomatosis cases in dairy cows in Turkey

Papillomaviruses (PVs) are epitheliotropic viruses that cause benign proliferative lesions in the skin (warts or papillomas) and mucous membranes of their natural hosts. In bovines specifically, 13 types of Bovine papillomaviruses (BPVs) are currently described in the literature, although the actual number may be greater than 20. BPV types are classified into four genera based on homology within the genomic regions of the L1 ORF, the most conserved sequence. This study conducted molecular typing of BPV in dairy cows with different papillomatosis cases and investigated the presence of co-infections across distinct BPV types in the same sample. After carrying out PCR using degenerate primers and type specific primers, 35 BPV suspected samples were detected as positive for BPV and these samples were used for typing using sequence analysis/PCR with type-specific primers. This analysis identified BPV-1, -2, -3, -4, -6, -7, -9 and -10, new putative types (BPV/BR/UEL6-like viruses) and the previously described putative type viruses (BAPV-6) in the 35 BPV-positive samples. In addition, co-infections across different BPV types were widely detected in the BPV-positive samples.  This study shows that PCR assays using degenerate primers to amplify partial fragments of the L1 gene followed by sequencing is useful for genotyping BPV. However, results need confirmation using type-specific primers in order to consider co-infections. In addition, this study identified a new putative type (in the same cluster as BPV/BR/UEL6-like viruses) and the previously described putative type viruses (BAPV-6) in teat papillomatosis of Turkish dairy cows. The study shows that it is essential to identify BPV types and their prevalence/distribution, and also to determine the clinical consequences of infection for the development of prophylactic and/or therapeutic procedures.

Molecular and histological characterization of bovine papillomavirus in North West Italy

Bovine papillomaviruses (BPVs) are group of worldwide-spread DNA virus that infect primarily cattle determining diseases of considerable economic relevance. Recently, research on BPVs, received a great impulse owing to the development of specific biomolecular analysis, mostly based on L1 gene sequencing, that resulted in the identification of new viral types. This work is aimed at the identification and molecular and histopathological characterization of BPVs circulating in North West Italy, one of the main national cattle breeding areas. In this study, 71 bioptic specimens were submitted both to histological examination and to PCR and sequencing analysis. Histopathology revealed various lesion types; however, no connections were demonstrated between involved viral types and histopathological findings. BPV DNA was demonstrated in all the analyzed samples and several viral types were detected. Particularly, molecular investigations revealed a broad diffusion of highly pathogenic BPV1 and 2 Deltapapillomavirus and presence of BPV3 and 9 Xipapillomavirus. Two cases of co-infection were also demonstrated. Phylogenetic analysis revealed presence of different clusters and therefore a noteworthy genetic variety among the analyzed viral types. This study provides information on the main BPVs types in North West Italy and our results demonstrate the complexity of viral epidemiology which is characterized by circulation of multiple viral types even inside single herds. Knowledge of the prevalence and of the variety of BPVs is a milestone for the development of appropriate prophylactic and therapeutic measures.

Caracterização molecular de DNA de Delta papillomavirus bovino (BPV1, 2 e 13) em sarcoides equinos

Resumo:Sarcoides são tumores fibroblásticos, considerados os tumores de pele mais comuns em pele de equinos e que raramente apresentam regressão espontânea. Papilomavírus bovino (BPV) tipos 1 e 2 são relacionados com a patogenia do sarcoide e, provavelmente, o BPV tipo 13 (BPV13), recentemente descrito, também pode estar associado com a formação dessa lesão. Neste estudo, 20 amostras de lesões cutâneas, sendo 12 constituídas por tecidos frescos e 8 amostras de tecido fixado em formalina e embebido em parafina, provenientes de 15 cavalos foram utilizadas para a identificação do DNA de BPV. A análise histopatológica (HE) confirmou todas as lesões como sarcoide. Para a amplificação do DNA de papilomavírus (PV) foram realizadas três reações de PCR. Como triagem, os primers IFNR2/IDNT2 foram utilizados para amplificar um fragmento da ORF L1 do PV. O segundo par de primersutilizado é complementar a sequência dos genes E5 e L2 de BPVs 1, 2 e 13. O terceiro par de primers(FAP59/FAP64) utilizado tem o gene L1 como alvo. A primeira e a segunda PCRs permitiram amplificar produtos em todas as amostras avaliadas. Entretanto, na terceira reação, na qual foram utilizados os primers FAP, foi possível amplificar produtos com tamanho molecular esperado somente nas amostras constituídas por tecidos frescos. O sequenciamento de nucleotídeos e as análises filogenéticas realizadas nos fragmentos E5L2 resultaram na identificação de BPV1, 2 e 13 em 14 (70%), 2 (10%) e em 4 (20%) amostras de sarcoides, respectivamente. As amostras de sarcoides de um dos animais continha somente o DNA de BPV1. Entretanto, nas amostras provenientes do segundo cavalo foi possível identificar o DNA de três tipos de Deltapapillomavirus bovino (BPV1, 2 e 13) em lesões distintas. Este estudo ratifica a presença do DNA de BPV1, 2 e 13 em lesões de sarcoides em equinos, além de identificar três tipos de BPVs em um mesmo animal e descrever pela primeira vez no Brasil a presença de BPV1 e 2 nesse tipo de lesão.

Mixed Nipple Infections Caused by Variant of BPV3 and a Putative New Subtype of BPV in Cattle

Bovine papilloma is a chronic and proliferative skin and mucosal wart caused by Bovine papillomavirus (BPV). In June, 2013, a leaf-and flat-shaped wart disease was observed on the nipple skins in a cattle farm in Xinjiang. To diagnose the disease, we collected the diseased skins for pathological biopsy and DNA analysis by PCR amplification using a pair of degenerate primers FAP59 and FAP64. Sequencing and phylogenetic analysis showed that the infection was caused by a variant of BPV3 and putatively a new subtype of BPV (BPV/CHI-SW1, belonging to the Xi papillomavirus genus). This is the first report of mixed infection caused by variant of BPV3 and BPV (putatively new subtype) in China, and would be of importance for the molecular epidemiological study of the disease.

Bovine Papillomavirus: New Insights into an Old Disease

Bovine papillomaviruses (BPVs) are small DNA tumoral viruses able to induce benign cutaneous and/or mucosal epithelial lesions. Generally, the benign tumours affecting the skin or mucosa spontaneously regress, but under special circumstances, the defence system may be overwhelmed, thus leading to cancer, especially in the presence of immunosuppressant and mutagen agents from bracken fern. To date, thirteen different BPV genotypes have been associated with skin and mucosal tumours in cattle, and out of these, only four types (BPV-1, -2, -5 and -13) cross-infect other species. Recent investigations in vivo have revealed new insights into the epidemiology and pathogenesis of this viral infection. This review briefly discusses viral epidemiology, will give data on BPV genome structure and viral genes and will describe the cellular events and new aspects of both cutaneous and mucosal tumours in large ruminants. Finally, some aspects of active immunization will be described.

Detection and typing of common human papillomaviruses among Jordanian patients

The epidemiology of human papillomaviruses (HPVs) genotype distribution of cutaneous warts in Jordanian patients were studied. A total of 200 samples were collected using skin swabs from patients with warts attending the dermatology clinic at the Jordan University Hospital over the period of June 2010 to October 2010. Another 100 control samples were taken from healthy Jordanian individuals with no current or previous history of warts. DNA extraction and sequencing was carried out using PCR with the FAP primer pair to detect HPV DNA, followed by multiple-type-specific (Multiplex) PCR combined with DNA sequencing. The prevalence of HPV among Jordanian patients tested with warts diagnosed clinically was 82% (157/192); of these 45% (87/192) were detected by FAP PCR method, and 37% (70/192) were detected by multiplex PCR method. Sequencing of the FAP positive samples shows that HPV 2 was associated with the highest prevalence (36%), followed by HPV 27 (28%) and HPV 57 (21%). A total of 6% of healthy persons were positive for HPV DNA. In conclusion, this study demonstrates that alpha HPV types (HPV 2, HPV 27, and HPV 57) are associated with the most prevalent cutaneous warts in Jordanian patients.

Bovine papillomavirus: opening new trends for comparative pathology

For many years, research on bovine papillomavirus (BPV) has contributed to the understanding of papillomavirus-induced pathology in humans and animals. The present review shows how recent studies on BPV keep providing evidence concerning key points in viral infection, such as the expression of viral proteins in lymphocytes and the occurrence of productive infections of the placenta. Studies on BPV-induced tumours also provide important information concerning the mechanisms of oncogenesis and immune evasion, as in the cases of connexin 43 down-regulation with loss of intercellular gap junctions and Toll-like receptor 4 (TLR4) down-regulation in equine sarcoids. The biological functions of viral proteins are also being further clarified, as in the case of E2, which was recently shown to load BPV genomes into host chromosomes during the S phase, a process mediated by the ChlR1 protein. In the near future, the ongoing efforts to characterize and classify additional emerging BPV types are likely to broaden even further the possibilities for research.

Bovine papillomavirus type 13 DNA in equine sarcoids

Equine sarcoids are locally aggressive fibroblastic neoplasms considered to be the most common skin tumors of horses worldwide. Bovine papillomavirus types 1 and 2 have typically been associated with sarcoids in equids. Investigations aiming to identify papillomavirus strains, aside from bovine papillomaviruses 1 and 2, which might be associated with sarcoid lesions, have been lacking. The aim of this article is to report the identification of a third bovine papillomavirus type, bovine papillomavirus 13, associated with equine sarcoids. Six sarcoid lesions were collected from diverse anatomical sites on two horses from southern Brazil. To detect a broad spectrum of papillomavirus strains, eight degenerate primer pairs designed to detect conserved regions on the L1 and E1 genes were tested on the DNA samples. Direct sequencing was then performed on the obtained amplicons, and sequence identities were compared with sequences from all bovine papillomavirus types. The FAP59/FAP64, MY09/MY11, and AR-E1F2/AR-E1R4 sequences generated from the sarcoids were shown to present 99 to 100% identity with bovine papillomavirus 13, a new bovine papillomavirus type previously described in cattle. The results from this study suggest that there is a need to identify bovine papillomavirus type 13 and other papillomavirus strains that might be associated with sarcoids in diverse geographical areas; such investigations might establish the frequency of occurrence of this viral type in these common tumors of equids.

The presence and gene expression of bovine papillomavirus in the peripheral blood and semen of healthy horses

Papillomavirus (PV) are double-stranded DNA viruses that can cause both benignant and malignant tumours in mammals. Twelve genotypes of bovine papillomavirus (BPV1-12) have been identified so far. The presence of BPV1 and 2 has been found in the body fluids of cattle and horses. The aim of this study is to investigate the presence of BPV DNA and the expression of viral genes in the blood and sperm cells of healthy horses using PCR and RT-PCR. BPV-1 or 2 was detected in 14 of 70 blood samples (20%) and in 11 of 31 semen samples (35%). In five of fourteen blood samples, the E5 expression tested positive, while no blood sample was positive for L1 expression. Four of 11 (36%) semen cell samples proved to be positive for E5 expression, while no gene expression in L1 could be detected. This is the first study that shows BPV1 gene expression in the blood and semen of healthy horses. Our data illustrate the need for a better understanding of the presence of BPV in non-epithelial tissues of horses and their role in the vertical and horizontal transmission of these viruses.