Bovine Papillomavirus Research Articles

Molecular and pathological characterization of teat papillomatosis in dairy cows in southern Brazil.

Teat papillomatosis is caused by different bovine papillomavirus (BPV) types and is especially important for dairy cows, because it results in severe damage to the health and structure of the mammary gland. This work describes the molecular and pathological aspects of teat papillomatosis in dairy cows in southern Brazil. Samples of teat papillomas were collect from 73 slaughtered dairy cows. Fragments of the lesions were collected in individual pools per animal and subjected to PCR using the FAP primer pair and sequencing of the amplification products. Teats with the remaining lesions were fixed in 10% neutral buffered formalin, routinely processed for histopathology, and stained with hematoxylin and eosin (H&E). Papillomatous lesions were characterized by three macroscopic patterns, namely exophytic (5 [6.9%]), flat (29 [39.7%]), and mixed (39 [53.4%]). Histologically, all samples were identified as squamous papillomas. Partial sequencing of the L1 gene resulted in the detection of 8 classical BPV types (BPVs 4, 6, 7, 8, 9, 10, 11, and 12) in 27 samples, 6 previously reported putative BPV types in 17 samples, and 10 putative new BPV types in 15 samples. Four sequences could not be classified, and 10 were negative in the PCR. There was no correlation between the gross pattern and the BPV type identified, and all the samples were characterized by squamous papillomas under histological examination. However, 24 different BPV types were identified, demonstrating high genetic diversity among BPVs associated with teat papillomatosis in dairy cows in southern Brazil.

Equine and bovine papillomaviruses from Turkish brood horses: a molecular identification and immunohistochemical study

Equine and bovine papillomaviruses from Turkish brood horses: a molecular identification and immunohistochemical study

Detection and whole genomic characterization of <em>Bovine Papillomavirus</em> type 1 associated with severe mammary cutaneous warts in Turkey

Papilloma viruses (PVs) induce epithelial tumors in their natural hosts. These tumors are located on the mammary gland of cattle; therefore, PVs are considered viral agents with significant effects, both economical and on the animals’ health. Also, knowing the diversity of bovine PV (BPV) and its prevalence in countries worldwide is important to develop optimal diagnostic methods, as well as methods to fight this infection.The aim of the present study was to characterize the full-length genome of BPV 1 as the dominant type circulating among cattle in Turkey. It is the authors’ opinion that the results of this work provide useful information for further studies on the preventative steps that can be taken against BPV infection.

Bovine papillomavirus load in equine sarcoids and normal equine skin

Bovine papillomavirus load in equine sarcoids and normal equine skin

Mitophagy mediated by BNIP3 and BNIP3L/NIX in urothelial cells of the urinary bladder of cattle harbouring bovine papillomavirus infection

Autophagy is a powerful tool that host cells use to defend against viral infection. Mitophagy, the selective autophagic removal of dysfunctional mitochondria was upregulated in urothelial cancer cells harbouring bovine papillomavirus (BPV) infection, as detected by the expression of BPV E5 protein, the major oncoprotein of bovine Deltapapillomavirus genus. HIF-1α-induced mitophagy receptors, BNIP3 and BNIP3L/Nix, were found to be overexpressed in these cells. The BNIP3 and BNIP3L/Nix receptors were amplified, and amplicon sequencing showed homology between bovine BNPI3 and BNIP3L/Nix sequences deposited in GenBank (accession number: NM_001076366.1 and NM_001034614.2, respectively). The transcripts and protein levels of BNIP3 and BNIP3L/Nix were significantly overexpressed in hypoxic neoplastic cells relative to healthy, non-neoplastic cells. BNIP3 and BNIP3L/Nix interacted with the LC3 protein, a marker of autophagosome (mitophagosome) membrane, ERAS, a small GTPase, and p62, known to be a specific autophagy receptor protein, that plays a role in mitochondrial priming for mitophagy and subsequent elimination. ERAS also interacted with the BPV E5 oncoprotein at mitochondrial level. Furthermore, in anti-Bag3 mitochondrial immunoprecipitates, a complex composed of the Hsc70/Hsp70 chaperone, CHIP co-chaperone, Synpo2, ERAS, LC3, p62, BNPI3, and BNIP3L/Nix was also detected. Bag3 may play a role in mitophagosome formation together with the Synpo2 protein and may be involved in the degradation of Hsc70/Hsp70-bound CHIP-ubiquitinated cargo, in association with its chaperone. ERAS may be involved in mitophagosome maturation via the PI3K signalling pathway. Ultrastructural findings revealed the presence of mitochondria exhibiting severe fragmentation and loss of cristae, as well as numerous mitochondria-containing autophagosomes.

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.

Integrated mRNA and miRNA profiling in NIH/3T3 cells in response to bovine papillomavirus E6 gene expression.

Delta bovine papillomaviruses (δBPVs) mainly infect cattle and cause fibropapillomas. δBPVs encode three oncogenes, E5, E6 and E7. The effect of E6 on microRNA (miRNA) and mRNA expression profiles is not well characterized. In this study, RNA sequencing and small RNA sequencing were used to explore alterations in mRNAs and miRNAs in E6 over-expressing NIH/3T3 cells (NH-E6) compared with control cells (NH-GFP). We found that 350 genes (181 upregulated and 169 downregulated) and 54 miRNAs (26 upregulated and 28 downregulated) were differentially expressed (DE) following E6 expression. The top 20 significantly enriched GO terms in “biological process” included inflammatory response, innate immune response, immune response, immune system process, positive regulation of apoptotic process, cell adhesion, and angiogenesis. We constructed a potential miRNA-gene regulatory network from the differentially expressed genes (DEGs) and DE miRNAs. Finally, we selected 19 immune-response related DEGs and 11 DE miRNAs for qPCR validation. Of these, upregulation of 12 genes, Ccl2, Ccl7, Cxcl1, Cxcl5, Tlr2, Nfkbia, Fas, Il1rl1, Ltbp1, Rab32, and Zc3h12a, Dclk1 and downregulation of four genes, Agtr2, Ptx3, Sfrp1, and Thbs1 were confirmed. Ccl2, Ccl7, Cxcl1 and Cxcl5 were upregulated more than ten-fold in NH-E6 compared with NH-GFP. Also, upregulation of three miRNAs, mmu-miR-129-2-3p, mmu-miR-149-5p-R-2 and mmu-miR-222-3p, and downregulation of five miRNAs, mmu-miR-582-3p-R+1, mmu-miR-582-5p, mmu-miR-708-3p, mmu-miR-708-5p and mmu-miR-1197-3p, were confirmed. Our study describes changes in both mRNA and miRNA profiles in response to BPV E6 expression, providing new insights into BPV E6 oncogene functions.

The structure of the extended E2 DNA-binding domain of the bovine papillomavirus-1.

Bovine papillomavirus proteins were extensively studied as a prototype for the human papillomavirus. Here, the crystal structure of the extended E2 DNA-binding domain of the dominant transcription regulator from the bovine papillomavirus strain 1 is described in the space group P31 21. We found two protein functional dimers packed in the asymmetric unit. This new protein arrangement inside the crystal led to the reduction of the mobility of a previously unobserved loop directly involved in the protein-DNA interaction, which was then modeled for the first time.

Detection and genomic characterization of Bovine papillomavirus isolated from Chinese native cattle.

Bovine papillomaviruses (BPV) are small circular DNA viruses which can be widely spread in herd, inducing cattle tumours, therefore, leading economic losses in dairy and beef production industries. BPV-leads symptoms include cutaneous papillomas, fibropapillomas, urinary bladder and oesophageal carcinoma. As one of the most important producers of beef in the world, China has not provided systematic research to prevent the harm of BPV, particularly in papillomavirus molecular characterization which presents among Chinese native cattle which was known to have higher disease resistance. In this study, skin papilloma was observed and samples were collected following by histopathological analysis. We analysed all neoplasms samples and reviewed their degrees in acanthosis and/or hyperkeratosis. Full-length genomic sequencing was applied for all four isolated strains (JX180408, LA150909, HX160815, and BS160810) to exploring the molecular reason why BPV currently prevalent in Chinese native cattle. As a result, we identified that these four isolates were classified as BPV-1 and clustered into the Deltapapillomavirus genera. Our study also identified that BPV 1 isolates from Chinese indigenous cattle breeds belong to subtypes A which has a closer genetic background compare with their common ancestor and suggest it can be a more ancestral species. European isolates more recently diverged group (group B) contained almost exclusively European samples. In this study, we analysed the similarity of ORF between Chinese isolated BPV 1 and BPV 1 reference strains and listed results. This study provides the complete genomic characterization of BPVs circulating in Chinese native cattle breeds for the first time, which provide a detailed description of how diverse strains may cause skin tumour among Chinese local breed cattle therefore critical for further epidemiological study of relevant diseases.

Detectie van runderpapillomavirus in een paardencellijn als contaminant

Boviene papillomavirussen (BPV) behoren tot de familie van Papillomaviridae. Papillomavirussen zijn meestal soortspecifiek en epitheliotroop. Delta-BPVs vormen een uitzondering op deze regel omdat ze ook fibroblasten en niet-boviene hoefdieren kunnen infecteren. Celcultuur is essentieel voor het uitvoeren van in-vitrostudies, analyse van virusbiologie, vaccinproductie, weefselmanipulatie en toxiciteitstesten. In deze context vormt cellulaire contaminatie een aanzienlijk probleem. In de voorliggende studie werden verscheidene cellijnen (n = 27) beoordeeld op mogelijke BPV-besmetting. Voor dit doel werd DNA geëxtraheerd uit een celcultuur en vervolgens gescreend op de aanwezigheid van papillomavirus L1-capsidegen DNA met behulp van een consensus-polymerasekettingreactie (PCR)- systeem. Immunofluorescentiekleuring (IF) werd gebruikt voor de detectie van virale eiwitten. Opmerkelijk was dat één cellijn afgeleid van paardendermis positief testte met PCR en met de daaropvolgende IF-kleuring voor L1. Amplicon-sequenering gevolgd door L1-DNA-sequentievergelijking leidde tot de identificatie van een vermoedelijk nieuw BPV-type dat de grootste gelijkenissen met Delta-BPV-typen 1 (76%) en 2 (73%) vertoonde. Volgens de auteurs is dit het eerste rapport over de aanwezigheid van een vermeende BPV als een virale contaminant in celculturen die mogelijk een tot nu toe onbekende Delta-BPV vertegenwoordigt.

The Presence and Prevalence of Bovine Parainfluenza 3 (BPIV-3), Bovine Papillomaviruses (BPV), Bovine Herpesvirus 1 (BHV-1) in Subclinical Mastitis in Cattle

In general, bacterial pathogens are the focus of mastitis studies. Symptoms of mastitis may be absent in cases of viral infection, because other clinical symptoms are more dominant. Subclinical mastitis cases cannot be generally diagnosed and as a consequence, they are not investigated very well. This may lead to the inability of viral agents to be predicted in bovine subclinical cases. There are many viral agents associated with bovine mastitis and which may cause subclinical mastitis in dairy cattle. However, since viral infections have not been much investigated in mastitis studies, strategies developed against subclinical mastitis may be inadequate. Bovine Parainfluenza 3 (BPIV-3), Bovine Papillomaviruses (BPV), Bovine Herpesvirus 1 (BHV-1) could cause clinical and subclinical mastitis. The aim of the present study was to investigate the presence and prevalence of BPIV-3, BPV, and BHV-1 viral agents in subclinical mastitis case in Erzurum province. For this purpose, 120 bovine mammary tissues with no macroscopic lesions were collected and these tissues were examined with histopathology and immunofluorescence methods. Thereafter, all viruses were identified with qRT-PCR in mammary tissues. The end of histopathologic process 78 of 120 cases (56 chronic subclinic mastitis, 22 acut mastitis) was found severity of inflammatory changes. According to the results of immunofluorescence staining for all sections. The immun positive signs for BPIV-3 BPV, and BHV-1 was determined in 50 out of 120 cases. qRT-PCR results which compatible with immunofluorescence results showed that BPIV-3 agent was detected by the qRT-PCR in 26/120 samples, BPV-2 agent in 8/120 samples, BHV-1 agent in 16/120 samples, and BPV-1 agent in 7/120 samples (only by qRT-PCR). Coinfection with BPIV-3 and BHV-1 was detected in 5/120 samples, BPIV-3, and BPV-1 in 3/120 samples, BHV-1, and BPV-2 in 2/120 samples. According to our results, although the role of viral agents in mastitis disease has not been clearly elucidated, we have found that viral agents are common in mammary tissues with subclinical mastitis.

Bovine papillomavirus E5 oncoprotein expression and its association with an interactor network in aggresome-autophagy pathway

E5 protein, the major oncoprotein of bovine Deltapapillomavirus (BPV), was found to be expressed in 18 of 21 examined urothelial cancers of cattle. E5 oncoprotein was found to interact with p62 which was degraded through the autophagosome-lysosome pathway as well as LC3-II and appeared to be involved in the phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α). Autophagy was morphologically documented by transmission electron microscope (TEM) through the detection of double-membrane autophagosomes and autolysosomes. Overexpression of Bag3 known to mediate selective autophagy was also demonstrated. Furthermore, Bag3 and BPV E5 oncoprotein were seen to co-localize with dynein and 14-3-3γ, which suggested that Bag3 could be involved in inducing the retrograde transport of BPV E5 along microtubules to aggresomes, perinuclear sites with high autophagic flux. Electron dense perinuclear structures consistent with aggresomes were also documented by TEM in urothelial cancer cells. Finally, Bag3 was found to also interact with synaptopodin 2 (Synpo2), which would seem to contribute to cargo degradation as it has been shown to facilitate autophagosome formation. This study provides mechanistic insights into the potential role(s) of autophagy in BPV disease, which can help to develop future treatment and control measures for BPV infection. Activation of autophagy correlates positively with BPV infection and may play a role in biological behavior of bladder cancer as urothelial carcinomas of cattle are known to be characterized by a relatively low rate of metastasis.

A retrospective study of viral skin diseases of cattle, sheep and goats in Plateau State, Nigeria

Viral skin diseases namely lumpy skin disease (LSD), bovine papilloma (BP), goat pox (GTP) and contagious ecthyma (CE) have been reported in Plateau State, but our search through literatures did not reveal any documented prevalence rates of these diseases. A retrospective study of LSD, BP, GTP and CE was carried out based on Jos abattoir (2005-2016) and laboratory records of National Veterinary Research Institute, Vom, Nigeria (2010-2016). Based on the Jos Abattoir records, the prevalence rates were as follows LSD: 0.13% and BP 0.5% in Cattle. The prevalence of CE was 4.2%in sheep and 3.6% in goats. While LSD was diagnosed only in 2005, 2008 and 2016, BP was diagnosed every year except 2013, 2015 and 2016. Comparatively, CE was diagnosed in every year and month of the period reviewed. The analysis of records revealed that 11 samples were submitted for lab confirmation from suspected cases of LSD, 45.4% of which were positive by PCR. Additionally, 10 samples submitted for lab confirmation from suspected cases of GTP and 40% of the samples analyzed were positive by PCR. Of the 11 samples submitted for lab confirmation of CE, 36.4% of samples were confirmed to be CE by PCR. The laboratory results validate the Jos abattoir records which confirm that LSD, GTP and CE occur in Plateau State, Nigeria. Keywords : Abattoir, Plateau State, Prevalence, Retrospective, Viral skin diseases

Phylogenetic tree analysis study of bovine papillomaviruses type 1 based on L1 gene in Al-Qadisiyah governorate, Iraq

Bovine fibropapilloma and papilloma occur in different parts of the skin of animals. Bovine Papillomavirus (BPV) is an oncogenic virus making benign tumor lesion of together mucosal and cutaneous tissue in cattle. In order to confirm the clinical diagnosis; the study planned to make the molecular detection of BPV (DNA) using Polymerase Chain Reaction (PCR) from skin lesions and the phylogenetic analysis. Thirty-eight samples of skin lesions were collected from cattle clinically suspected to be infected with bovine papilloma virus from herds in Al-Qadisiyah Governorate in 2016, the primary clinical diagnosis depended on the morphological appearance and features of the lesion. Deoxyribonucleic Acid (DNA) was extracted from skin lesions; the DNA was examined by PCR technique using specific primer to BPV-1 /L gene-1. Twenty-two samples out of 38 (57,9%), which were collected from different regions in Al-Qadisiyah Governorate, were positive. The sequences of four positive samples of DNA product amplification of (BPV) type-1, L1 gene confirmed the PCR results. These samples had the DNA presented in four accession numbers KY662042-1, KY662043-1, KY662040-1 and KY662041-1. This study proofed that cutaneous bovine papillomatosis related with BPV-1 infection in the cattle herds has affinity to solid skin rather than other epithelial and mucosal tissue.

Molecular Detection of Bovine Papillomavirus DNA in the Placenta and Blood of Healthy Mares and Respective Foals.

Despite the characteristic species specificity of Papillomaviruses (PVs), the bovine papillomavirus (BPV) types 1, 2, and—more rarely—13, can cross-infect equids, where they are involved in the pathogenesis of sarcoid neoplasms. Sarcoids are locally invasive fibroblastic skin tumors that represent the most common skin neoplasms in horses worldwide. The transmission mechanism of BPV is still controversial in horses. Thus far, direct and indirect routes have been implicated, while vertical transmission has been suggested after the detection of viral DNA in the semen of healthy stallions. Testing of the blood and placenta of non-sarcoid baring mares and their respective foals revealed that the equine placenta can harbor BPV DNA, leading us to speculate a possible prenatal vertical DNA transmission in equids.

No evidence of bovine papillomavirus type 1 or 2 infection in healthy equids.

There is a large body of evidence supporting bovine papillomavirus types 1 and 2 (BPV1; BPV2) as aetiological agents of equine sarcoids. However, there is conflicting data regarding BPV1/2 infection in sarcoid-free equids. Data obtained between 2007 and 2017 by BPV1/2 screening of sarcoids and nonsarcoid tumours vs. samples from healthy equids are presented to help clarify this issue. Cross-sectional study. Tumour material obtained from horses, donkeys and mules with confirmed sarcoids (n=130), suspected sarcoids (n=120), or nonsarcoid lesions (n=70), skin biopsies from 102 tumour-free horses and dandruff/hair roots from 35 tumour-free donkeys and mules were screened for BPV1/2 infection. Sample DNA was extracted and validated by equine β-actin PCR. BPV1/2 screening was performed by BPV1/2 E5-specific PCR allowing for the detection of less than 10 viral DNA molecules. Twenty-six amplicons were bidirectionally sequenced and compared to known E5 variants using BLAST program. BPV1/2 E5 PCR scored positive for 130/130 diagnosed sarcoids, 63/120 suspected sarcoids and 13/70 nonsarcoid lesions, whereas 137/137 DNA aliquots derived from tumour-free equids tested negative. On predicted E5 protein level, six different BPV1 E5 variants were identified. The diagnosis of equine sarcoid was not confirmed in 120 lesions. Lack of BPV1/2 E5 DNA in tumour-free equids and the prevalence of sarcoid disease in young adult individuals suggest that the time span between initial infection and sarcoid development is short. This contrasts with the long phase of virus latency characterising infection of humans by carcinogenic papillomaviruses. Presence of BPV1/2 DNA in several cases of poor wound healing/hypergranulation and dermatitis points to these skin disorders being possibly co-induced by BPV1/2. PCR screening of tumour tissue/scrapings for BPV1/2 DNA represents a reliable tool for the rapid validation of a clinical diagnosis of equine sarcoid.

Congenital papillomavirus infection in cattle: Evidence for transplacental transmission

Vertical transmission of bovine papillomavirus (BPV) infection was investigated on livers and kidneys of four foetuses from cows suffering from BPV-2-associated urothelial cancers of the urinary bladder. PCR analysis revealed the presence of BPV-2 E5 DNA in the livers and kidneys of two foetuses. Amplified DNA fragments, composed of 502 bp, showed a 100% homology with BPV-2 sequences (GenBank accession number: M20219.1). BPV-2 was found to be transcriptionally active. Indeed, reverse transcriptase (RT)-PCR showed BPV-2 E5 transcripts. Sequencing of amplified cDNA, composed of 154 bp, showed a 100% identity with BPV-2 E5 sequences (GenBank accession number: M20219.1). Western blot analysis revealed the presence of dimers of E5 oncoprotein. Furthermore, a statistically significant increase of the phosphorylated (activated) form of the platelet-derived growth factor ß receptor (PDGFßR) was also detected in the fetal tissues. PDGFßR is believed to form the most important interaction with the E5 oncoprotein, thus regulating biological activity of virus protein. The strong concordance between virus found in fetal organs with virus detected in infected mothers provides evidence that BPV-2 can spread through blood and vertical infection occurs via transplacental transmission. Finally, molecular findings of this study raise unsolved questions about the potential role of BPVs in reproductive disorders. The presence of E5 oncoprotein, as in adult organs, may also activate the constitutive receptor PDGFßR in foetal organs, which plays a pivotal role in angiogenesis and embryonic development. Therefore, abnormal phosphorylation of PDGFßR may be involved in vascular and organogenesis abnormalities other than cancer.

Expression of the feline leukemia virus subgroup C receptors in normal and neoplastic urothelium of the urinary bladder of cattle associated with bovine papillomavirus infection

The feline leukemia virus subgroup C receptors (FLVCRs) were originally cloned as virus receptors, but are now believed to function also as heme transporters and are expressed in a broad range of tissues in a wide range of mammalian species. Expression of FLVCR1 and FLVCR2 was investigated in 19 bovine papillomavirus-associated urinary bladder cancers and in 15 non-neoplastic samples of bladder from cattle. E5 oncoprotein of bovine Deltapapillomaviruses (δPVs) was detected in 17 of the 19 bladder cancers. Flvcr1 and Flvcr2 were amplified and sequenced both in neoplastic and non-neoplastic samples showing a 100% identity with bovine Flvcr1 and Flvcr2 mRNA sequences present in GenBank database (accession numbers: NM_001206019.1 and NM_001192143.1, respectively). Reverse transcription (RT)-PCR showed that Flvcr1 and Flvcr2 were overexpressed in 4 and 5 out of 19 urothelial cancers, respectively, but in none of the non-neoplastic samples. In addition, western blot analysis detected higher levels of FLVCR1 and FLVCR2 in samples in which transcripts were not increased, suggesting post-translational changes to these proteins. Increased FLCVR1 and FLVCR2 was also observed immunohistochemically in the neoplastic cells. Immunolabeling for FLVCR1 was seen in the cytoplasm and plasm membrane of urothelial cancer cells, wheras immunolabeling for FLVCR2 was present within the nucleus. This is the first time that FLVCR expression has been investigated in bovine tissues and the first to suggest that expression could be increased in cancers. Additional studies are required to define the role, if any, of FLVCR in papillomavirus-associated cancer cells.

Bovine Papillomavirus Type 1 in Brains of Cattle with a Neurological Syndrome: Pathological and Molecular Study

Bovine papillomavirus (BPV) infection is endemic in Brazilian herds. Papillomaviruses are oncogenic, with a trophic response in squamous epithelial and mucosal tissues, and are associated with asymptomatic infections, proliferative benign skin lesions (papillomas), and malignant epithelial lesions (carcinomas). The presence and expression of BPV in the blood of healthy and papillomatosis-affected cattle has been demonstrated. Experimental inoculation of Bovine papillomavirus (BPV) into calf meninges can result in meningiomas and papillomatosis, but it´s not known if its natural infection causes neoplasia and neurological syndrome in cattle. We assessed the frequency of BPV in 300 Central Nervous System (CNS) samples from cattle with neurological syndrome from several Brazilian regions obtained from surveillance of neurological syndrome. Samples were negative for rabies, Neospora caninum, BoHV-1 and BoHV-5, bovine leukemia virus, and catarrhal malignant fever (PCR). Samples were fixed in 10% buffered formalin and submitted to macroscopic examination. For histological analysis, slides were submitted to a staining protocol using hematoxylin and eosin. PCR for BPV detection was applied in CNS frozen samples using generic primers FAP59 and FAP64 (L1 gene). Thirteen (4.3%) samples were positive for BPV by PCR, with 11 of these showing no pathological changes in microscopy, and two exhibiting nonspecific non-purulent meningoencephalitis. No CNS samples showed neoplasia. Nine of the 13 BPV positive samples (69.2%) came from females and four (30.8%) from males. The 13 positive animals were age 5 to 168 months with seven over 36 months (53.8%). Five were dairy cattle, four crossbred, and three beef cattle. Only one of the 13 positive samples provided sufficient BPV DNA for sequencing, which emonstrated 99% identity to samples of BPV-1 obtained from cutaneous papillomas in cattle in Brazil. The small quantity of BPV DNA in the CNS and the low number of PCR-positive samples may be associated with low neurotropism, unspecific inflammation, or BPV-infected lymphocytes in CNS tissues or bloodstream. Natural BPV-1 infection was not associated with cerebral neoplasia or neurological syndrome.