Teat papillomatosis in dairy herds: First detection of bovine papillomavirus type 10 in China

Phylogenetic analysis and searching bovine papillomaviruses in teat papillomatosis cases in cattle by performing histopathology, immunohistochemistry, and transmission electron microscopy

Papillomaviruses are epitheliotropic in nature and cause proliferation in the skin, mucosa, and various internal organs of various animal species. The lesions they cause, specifically in cattle teats, lead to significant economic losses in the milk industry. In this study, we identified the bovine papillomaviruses (BPVs) responsible for teat papillomas in cattle. The tissue damage caused by the virus was examined histopathologically using immunohistochemical, transmission electron microscopy (TEM), and molecular methods. Additionally, sequence analyses were performed on the isolated field strains to better understand their genetic and phylogenetic relationships with previously reported isolates. Teat papillomatosis was confirmed in the collected samples by histopathological and immunohistochemical methods, which were followed by other diagnostic methods. Intranuclear virus particles were found in the epithelial cells during a TEM examination of teat lesions. BPV was detected in seven samples by performing PCR using degenerate primers and specific primers. The positive samples were used for typing through sequence analysis/PCR with type-specific primers. Three isolates from teat tissues with BPV infection were identified as BPV-6, two as BPV-10, one as BPV-2, and one as BPV-8. The five isolates identified through sequence analysis of positive samples belonged to the Xipapillomavirus 1 genus (one), the Epsilonpapillomavirus 1 genus (one), and the Deltapapillomavirus genus (one) (three). Furthermore, type-specific primers were found to be useful for molecular diagnosis of BPV, which occurs in the etiology of teat papillomas, followed by genotyping and primer generation during characterization. The detection of BPV types and their prevalence, biosafety measures in animal breeding, and the importance of vaccine research are all important.

Molecular characterization and pathological identification of a novel strain of delta papillomavirus-4 (bovine papillomavirus-2) in Egypt

Background and Aim:

Bovine papillomaviruses (BPV) are a heterogeneous group of oncoviruses, distributed globally, which produce major economic losses. In the current study, we compared the results of different diagnostic approaches and compared the strains identified in this study with previously characterized strains at local and international levels.

Materials and Methods:

Samples of skin warts were collected from five bovines with generalized papillomatosis from two Egyptian provinces, Menya and Ismailia, in 2020. Electron microscopy, molecular characterization, histopathological, and immunohistochemical examination were performed.

Results:

BPV was detected using electron microscopy in the collected samples. Using molecular characterization, BPV-2 was successfully identified for 1^st time in Egypt. The strain has 99.6% identity with the BPV-2 reference strains obtained from GenBank. These results were supported by histopathology and immunohistochemistry examination. Partial nucleotide sequences of the L1 gene were submitted to GenBank with accession numbers MW289843 and MW289844.

Conclusion:

BPV-2 was reported for 1^st time in the current study. The strain was identified grossly, microscopically, and pathologically and confirmed using molecular approaches. All results were consistent. The sequence analysis revealed that this strain has high sequence similarity to the reference Deltapapillomavirus-4, BPV-2 strains from Brazil and China.

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.

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.