Genetic diversity of bovine papillomavirus types, including two putative new types, in teat warts from dairy cattle herds

The genetic diversity of "papillomavirome" in bovine teat papilloma lesions

Background

Papillomaviruses are small nonenveloped, circular double-stranded DNA viruses that belong to the Papillomaviridae family. To date, 29 Bos taurus papillomavirus (BPV) types have been described. Studies involving mixed BPV infections have rarely been reported in contrast to human papillomavirus (HPV), which is commonly described in numerous studies showing coinfections. Moreover, previous studies had shown that HPV coinfections increase the risk of carcinogenesis. In the present study, we used rolling-circle amplification followed by a high-throughput sequencing (RCA-HTS) approach in 23 teat papillomas from southern Brazil.

Results

Eleven well-characterized BPV types and 14 putative new BPV types were genetically characterized into the Xi, Epsilon and Dyoxipapillomavirus genera according to phylogenetic analysis of the L1 gene, which expands the previous 29 BPV types to 43. Moreover, BPV coinfections were detected in the majority (56.3%) of the papilloma lesions analyzed, suggesting a genetic diverse “papillomavirome” in bovine teat warts.

Conclusions

The data generated in this study support the possibility that a wide range of BPV is probably underdetected by conventional molecular detection tools, and that BPV coinfections are underestimated and probably genetic diverse. Additionally, 14 new BPV types were characterized, increasing the knowledge regarding BPV genetic diversity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-021-00114-3.

Complete genome and phylogenetic analysis of bovine papillomavirus type 15 in Southern Xinjiang dairy cow

Background

Bovine papilloma is a neoplastic disease caused by bovine papillomaviruses (BPVs), which were recently divided into 5 genera and at least 24 genotypes.

Objectives

The complete genome sequence of BPV type 15 (BPV Aks-02), a novel putative BPV type from skin samples from infected cows in Southern Xinjiang China, was determined by collecting warty lesions, followed by DNA extraction and amplicon sequencing.

Methods

DNA was analyzed initially by polymerase chain reaction (PCR) using the degenerate primers FAP59 and FAP64. The complete genome sequences of the BPV Aks-02 were amplified by PCR using the amplification primers and sequencing primers. Sequence analysis and phylogenetic analysis were performed using bio-informatic software.

Results

The nucleotide sequence of the L1 open reading frame (ORF) of BPV Aks-02 was 75% identity to the L1 ORF of BPV-9 reference strain from GenBank. The complete genome consisted of 7,189 base pairs (G + C content of 42.50%) that encoded 5 early (E8, E7, E1, E2, and E4) and 2 late (L1 and L2) genes. The E7 protein contained a consensus CX₂CX₂₉CX₂C zinc-binding domain and a LxCxE motif. Among the different members of this group, the percentages of the complete genome and ORFs (including 5 early and 2 late ORFs) sequence identity of BPV Aks-02 were closer to the genus Xipapillomavirus 1 of the Xipapillomavirus genus. Phylogenetic analysis and sequence similarities based on the L1 ORF of BPV Aks-02 revealed the same cluster.

Conclusions

The results suggest that BPV type (BPV Aks-02) clustered with members of the Xipapillomavirus genus as BPV 15 and were closely related to Xipapillomavirus 1.

Molecular detection and genetic diversity of bovine papillomavirus in dairy cows in Xinjiang, China

Background

Bovine papillomatosis is a type of proliferative tumor disease of skin and mucosae caused by bovine papillomavirus (BPV). As a transboundary and emerging disease in cattle, it poses a potential threat to the dairy industry.

Objectives

The aim of this study is to detect and clarify the genetic diversity of BPV circulating in dairy cows in Xinjiang, China.

Methods

122 papilloma skin lesions from 8 intensive dairy farms located in different regions of Xinjiang, China were detected by polymerase chain reaction. The genetic evolution relationships of various types of BPVs were analyzed by examining this phylogenetic tree.

Results

Ten genotypes of BPV (BPV1, BPV2, BPV3, BPV6, BPV7, BPV8, BPV10, BPV11, BPV13, and BPV14) were detected and identified in dairy cows. These were the first reported detections of BPV13 and BPV14 in Xinjiang, Mixed infections were detected, and there were geographical differences in the distribution of the BPV genotypes. Notably, the BPV infection rate among young cattle (< 1-year-old) developed from the same supply of frozen sperm was higher than that of the other young cows naturally raised under the same environmental conditions.

Conclusions

Genotyping based on the L1 gene of BPV showed that BPVs circulating in Xinjiang China displayed substantial genetic diversity. This study provided valuable data at the molecular epidemiology level, which is conducive to developing deep insights into the genetic diversity and pathogenic characteristics of BPVs in dairy cows.

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.

Anogenital-Associated Papillomaviruses in Animals: Focusing on Bos taurus Papillomaviruses

In contrast to the diverse studies on human papillomaviruses (HPVs), information on animal PVs associated with anogenital lesions is limited. In the animal kingdom, papillomas occur more commonly in cattle than in any other animals, and diverse types of Bos taurus papillomaviruses (BPVs) exist, including the very recently discovered BPV type 29 (BPV29). From this perspective, we will review previous studies describing PV types associated with anogenitals in animals, with a focus on BPVs. To date, two classical BPV types, classified into Deltapapillomavirus (BPV1 and BPV2) and Dyokappapapillomavirus (BPV22), and two novel Xipapillomaviruses (BPV28 and BPV29) have been identified from anogenital lesions and tissues of the domestic cow. Due to the limited reports describing anogenital-associated PVs in animals, the relationships between their phylogenetic and pathogenetic properties are still undiscovered. Animal studies are valuable not only for the veterinary field but also for human medicine, as animal diseases have been shown to mimic human diseases. Studies of anogenital-associated PVs in animals have a positive impact on various research fields.

Development of immunogenic chimeric virus-like particles based on bovine papillomavirus type 6

Virus-like particles (VLPs) are considered useful tools for vaccine development because they induce an immune response and are safe. In addition, VLPs may be useful as a platform for the presentation of foreign antigens to elicit immune responses. In this study, we aimed to produce a chimeric VLP composed of L1 protein of bovine papillomavirus type 6 (BPV6-L1) that can display an entire foreign protein on its surface. Based on prediction of the conformational structure of VLP of BPV6-L1 (BPV6-VLP), candidate insertion sites for the foreign protein into BPV6-VLP were identified. Fusion proteins of BPV6-L1 and EGFP as a model foreign protein were constructed and produced. Only the fusion protein in which EGFP was inserted between amino acids 136 and 137 of BPV6-L1 self-assembled into VLPs and did not exhibit hindrance of the conformation of EGFP. Chimeric BPV6-VLP-immunized mice produced specific IgG against both BPV6 and EGFP. This is the first demonstration of the production of an immunogenic, bivalent, chimeric BPV6-VLP incorporating an entire protein for stable surface display. Thus, immunogenic chimeric BPV6-VLP may constitute a promising vaccine platform.

High Genotypic Diversity, Putative New Types and Intra-Genotype Variants of Bovine Papillomavirus in Northeast Brazil

Bovine papillomavirus (BPV) can cause damage to the epithelial and mucosal tissue and currently presents 28 known types. Not all BPV types are associated with the development of cancer in cattle. Studies have shown that variants of human papillomavirus types can present different pathogenic profiles. However, despite the similarity, it is not yet known whether variants of BPV types can also present varying degrees of pathogenicity. Thus, the aim of this study was to evaluate the genetic variability of BPV types and variants isolated in Northeastern Brazil. Samples were obtained from animals with papillomatous lesions. BPV DNA was detected by the amplification of the L1 gene and genotyping was performed by sequencing. Mutations were analyzed in a phylogenetic, structural and functional context. In total, 52 positive samples were obtained and 11 different BPV types were identified in the samples. Ten putative new BPV types were also identified. In addition, several non-synonymous mutations were identified and predicted to alter protein stability, having an impact on immune evasion. The study demonstrated a high genetic diversity of BPV in the region with a large number of mutations identified, serving as a basis for more efficient control measures to be adopted for bovine papillomatosis.

Production of immunogenic recombinant L1 protein of bovine papillomavirus type 9 causing teat papillomatosis

Bovine papillomavirus type 9 (BPV9) is a causative agent of severe teat papillomatosis. Considering the lack of efficient BPV culture methods, recombinant proteins such as virus-like particles developed through genetic engineering may serve as a useful tool for developing effective vaccines against BPV infection. In this study, we successfully produced immunogenic particles composed of recombinant L1 protein of BPV9 (rBPV9-L1), using a baculovirus expression system. rBPV9-L1-immunized mice produced BPV9-specific IgG, which did not cross-react with BPV type 6, which is another causative agent of teat papillomatosis. Hence, immunogenic rBPV9-L1 is potentially applicable as a vaccine candidate for teat papillomatosis.

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).

Genetic characterization of a putative new type of bovine papillomavirus in the Xipapillomavirus 1 species in a Brazilian dairy herd

Currently, bovine papillomavirus types are divided into five genera, namely, Deltapapillomavirus, Epsilonpapillomavirus, Xipapillomavirus, Dyoxipapillomavirus, and Dyokappapapillomavirus. In the recent decades, the characterization of numerous putative and novel bovine papillomavirus types from cattle in several geographic regions, has revealed the occurrence of a high viral diversity. In this study, we describe the identification and characterization of a putative new bovine papillomavirus type within species Xipapillomavirus 1 of Xipapillomavirus genus. The detection of the viral types identified in the skin warts was obtained by polymerase chain reaction assays targeting the L1 gene, followed by direct sequencing of the generated amplicons. The partial L1 sequences revealed that bovine papillomavirus types 6, 10, and 11, the putative new bovine papillomavirus type designated BPV/CHI-SW2, and an unreported putative new bovine papillomavirus type (named BPV/BR-UEL08) were associated with cutaneous papillomatosis in the cows from the dairy herd investigated. Phylogenetic reconstruction based on the L1 gene revealed that the BPV/BR-UEL08 isolate clustered with other bovine papillomaviruses classified in the Xipapillomavirus genus, being closely related to representatives of the species Xipapillomavirus 1. Investigations focusing on the molecular epidemiology of bovine papillomaviruses related to clinical outcomes in cattle are of fundamental importance to determine the actual genetic diversity and prevalent viral types to be included in vaccines for cattle.

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.

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.