Detection of papillomavirus DNA in precancerous lesions of the ears of sheep

Vertical Intrauterine Bovine and Ovine Papillomavirus Coinfection in Pregnant Cows

There is very little information available about transplacental infections by the papillomavirus in ruminants. However, recent evidence has emerged of the first report of vertical infections of bovine papillomavirus (BPV) in fetuses from naturally infected, pregnant cows. This study reports the coinfection of BPV and ovine papillomavirus (OaPV) in bovine fetuses from infected pregnant cows suffering from bladder tumors caused by simultaneous, persistent viral infections. Some molecular mechanisms involving the binary complex composed of Eras and platelet-derived growth factor β receptor (PDGFβR), by which BPVs and OaPVs contribute to reproductive disorders, have been investigated. A droplet digital polymerase chain reaction (ddPCR) was used to detect and quantify the nucleic acids of the BPVs of the Deltapapillomavirus genus (BPV1, BPV2, BPV13, and BPV14) and OaPVs belonging to the Deltapapillomavirus (OaPV1, OaPV2, and OaPV4) and Dyokappapapillomavirus (OaPV3) genera in the placenta and fetal organs (heart, lung, liver, and kidneys) of four bovine fetuses from four pregnant cows with neoplasia of the urinary bladder. A papillomaviral evaluation was also performed on the bladder tumors and peripheral blood of these pregnant cows. In all fetal and maternal samples, the genotype distribution of BPVs and OaPVs were evaluated using both their DNA and RNA. A BPV and OaPV coinfection was seen in bladder tumors, whereas only BPV infection was found in peripheral blood. The genotype distribution of both the BPVs and OaPVs detected in placentas and fetal organs indicated a stronger concordance with the viral genotypes detected in bladder tumors rather than in peripheral blood. This suggests that the viruses found in placentas and fetuses may have originated from infected bladders. Our study highlights the likelihood of vertical infections with BPVs and OaPVs and emphasizes the importance of gaining further insights into the mechanisms and consequences of this exposure. This study warrants further research as adverse pregnancy outcomes are a major source of economic losses in cattle breeding.

Ovine papillomaviruses: Diversity, pathogenicity, and evolution

The family Papillomaviridae includes a plethora of viral species infecting virtually all vertebrates excluding amphibians, with astonishing impact on human and animal health. Although more than 250 species have been described in humans, the total number of papillomaviruses (PVs) discovered in animals does not reach up to this number. In animals, PV infections are mostly asymptomatic or can cause variable clinical conditions ranging from self-limiting papillomas and other cutaneous and mucosal benign lesions to cancer. Most of animal PV types have been discovered in cattle, dogs, horses, and cats with other farm host species remaining overlooked. In particular, the number of PV types so far identified in sheep is limited. This paper comprehensively reviews ovine PVs features, including viral taxonomy and evolution; genome organization; viral tropism and pathogenesis; macroscopical features and histopathological patterns, as well as available diagnostics tools. Data are critically presented and discussed in terms of impact on veterinary and public health. The development of future dedicated research is also discussed.

Possible etiological association of ovine papillomaviruses with bladder tumors in cattle

INTRODUCTION

Bladder tumors of cattle are very uncommon accounting from 0.1% to 0.01% of all bovine malignancies. Bladder tumors are common in cattle grazing on bracken fern-infested pasturelands. Bovine papillomaviruses have a crucial role in tumors of bovine urinary bladder.

AIM OF THE STUDY

To investigate the potential association of ovine papillomavirus (OaPV) infection with bladder carcinogenesis of cattle.

METHODS

Droplet digital PCR was used to detect and quantify the nucleic acids of OaPVs in bladder tumors of cattle that were collected at public and private slaughterhouses.

RESULTS

OaPV DNA and RNA were detected and quantified in 10 bladder tumors of cattle that were tested negative for bovine papillomaviruses. The most prevalent genotypes were OaPV1 and OaPV2. OaPV4 was rarely observed. Furthermore, we detected a significant overexpression and hyperphosphorylation of pRb and a significant overexpression and activation of the calpain-1 as well as a significant overexpression of E2F3 and of phosphorylated (activated) PDGFβR in neoplastic bladders in comparison with healthy bladders, which suggests that E2F3 and PDGFβR may play an important role in OaPV-mediated molecular pathways that lead to bladder carcinogenesis.

CONCLUSION

In all tumors, OaPV RNA could explain the causality of the disease of the urinary bladder. Therefore, persistent infections by OaPVs could be involved in bladder carcinogenesis. Our data showed that there is a possible etiologic association of OaPVs with bladder tumors of cattle.

Molecular Epidemiology of Ovine Papillomavirus Infections Among Sheep in Southern Italy

Ovine papillomaviruses (OaPVs) were detected and quantified, for the first time, using droplet digital polymerase chain reaction (ddPCR) and real-time quantitative PCR (qPCR) via blood samples of 165 clinically healthy sheep. OaPV DNA was detected in 126 blood samples (~76.4%). DdPCR detected OaPV DNA in 124 samples; in only two additional samples positive for real-time qPCR, ddPCR failed to detect the presence of any OaPVs. In 70 of the positive samples (~55.6%), a single OaPV infection was observed, 12 of which were caused by OaPV1 (~17.1%) and 14 by OaPV2 (20%). OaPV3 was responsible for 19 single infections (~27.1%), and OaPV4 for 25 single infections (~35.7%). Multiple OaPV coinfections were observed in 56 (~44.4%) positive samples. OaPV coinfections caused by two genotypes were observed in 31 positive samples (~55.4%), with dual OaPV3/OaPV4 infection being the most prevalent as seen in 11 blood samples. In addition, five OaPV1/OaPV4, four OaPV1/OaPV2, four OaPV2/OaPV3, four OaPV1/OaPV3, and three OaPV2/OaPV4 dual coinfections were also detected. OaPV coinfections by triple and quadruple genotypes were detected in 24 (~42.8%) and only one (~1.8%) of coinfected blood samples, respectively. Multiple infections caused by OaPV1/OaPV3/OaPV4 genotypes were the most prevalent, as observed in 12 (50%) blood samples harboring triple OaPV infections. This study showed that ddPCR is the most sensitive and accurate assay for OaPV detection and quantification thus outperforming real-time qPCR in terms of sensitivity and specificity. Therefore, ddPCR may represent the molecular diagnostic tool of choice, ultimately providing useful insights into OaPV molecular epidemiology and field surveillance.

First detection of bovine papillomavirus type 2 in cutaneous wart lesions from ovines

This study diagnosed cutaneous wart lesions excised from three rams from a sheep farm in São Paulo State, Brazil. Histopathologically, these cases were diagnosed as papilloma. The amplification by PCR, sequencing and bioinformatics analysis showed that all the lesions presented DNA sequences of bovine papillomavirus type 2. This is the first report confirming the detection of BPV2 in papilloma warts from ovines.

Detection of bovine Deltapapillomavirus DNA in peripheral blood of healthy sheep (Ovis aries)

Blood samples from 65 sheep were tested for the presence of bovine Deltapapillomavirus (δPVs) DNA. The sheep were divided into three groups. Sheep in groups 1 and 2 were from Sardinia and Campania, respectively, and were in contact with cattle and grazed on lands contaminated with bracken fern. Sheep in Group 3 lived in closed pens and had no contact with cattle. These sheep were fed hay that did not contain bracken fern. Bovine δPV E5 DNA was detected in blood from 24 of 27 (89%) sheep in Group 1. A single bovine δPV type was detected in the blood from nine (33%) sheep, including the detection of bovine δPV-1 DNA in four sheep, bovine δPV-2 in four and δPV-13 in one sheep. Two δPV types were detected in 33% of the sheep, and three bovine δPV types were detected in 22% of the sheep. Bovine δPVs were detected in 17 of 20 (85%) sheep from Group 2. The detection rate by a single δPV type was 40% with just δPV-1 DNA amplified from two, just δPV-2 DNA from four, and just δPV-13 DNA from two sheep. Two and three δPVs were detected in 30% and 15%, respectively. All sequenced amplicons showed a 100% identity with papillomaviral E5 DNA deposited in GenBank. Bovine δPV-14 DNA sequences were not detected from any sheep. No bovine δPV DNA was revealed in blood samples from sheep in Group 3. The detection of bovine δPV DNA in the blood of sheep means that sheep may be able to be infected by these PVs. This suggests that bovine δPVs could potentially be a previously unrecognized cause of disease in sheep. Furthermore, it is possible that sheep could act as a reservoir for these viruses.

In vitro and Animal Models for Antiviral Therapy in Papillomavirus Infections

The need for antiviral therapies for papillomavirus infections is well recognized but the difficulties of reproducing the infectious cycle of papillomaviruses in vitro has hindered our understanding of virus-cell interactions and the regulation of viral gene expression during permissive growth. Recent advances in understanding the temporal expression and function of papillomavirus proteins has enabled consideration of a targeted approach to papillomavirus chemotherapy and in particular the inhibition of viral replication by targeting the E1 and E2 proteins. There are in vitro culture systems available for the screening of new chemotherapeutic agents, since significant advances have been made with culture systems which promote epithelial differentiation in vitro. However, to date, there are no published data which show that virions generated in vitro can infect keratinocytes and initiate another round of replication in vitro. In vivo animal models are therefore necessary to assess the efficacy of antivirals in preventing and treating viral infection, particularly for the low-risk genital viruses which are on the whole refractory to culture in vitro. Although papillomaviruses affect a wide variety of hosts in a species-specific manner, the animals most useful for modelling papillomavirus infections include the rabbit, ox, mouse, dog, horse, primate and sheep. The ideal animal model should be widely available, easy to house and handle, be large enough to allow for adequate tissue sampling, develop lesions on anatomical sites comparable with those in human diseases and these lesions should be readily accessible for monitoring and ideally should yield large amounts of infectious virus particles for use in both in vivo and in vitro studies. The relative merits of the various papillomavirus animal models available in relation to these criteria are discussed.

Squamous cell carcinoma of the vagina and cervix in sheep - case report

This report describes the clinical and histopathological characteristics of a squamous cell carcinoma infiltrating the cervix and the vaginal wall, producing reproductive symptoms and subnormal fertility in an adult ewe. Necropsy showed a large (15-cm-long) neoplastic mass infiltrating the vaginal wall and the cervix. Histopathological examination revealed atypical squamous epithelial cords invading the basal membrane and dermis, round anaplastic cells, focal areas of necrosis, keratinisation of isolated cells, and pronounced infiltration by mononuclear cells around the cords. No squamous cell carcinoma of such localisation has been reported from sheep before. In humans, this tumour is the most common gynaecological malignancy in the world.

Presence of papillomavirus-like DNA sequences in cutaneous fibropapillomas of the goat udder

Papillomatous lesions were isolated from the mammary skin of goats and examined for evidence of papillomavirus (PV) infection by various criteria, including gross morphology, histology and DNA hybridization. Although some lesions showed gross papillomatous morphological and histological features similar to those caused by papillomavirus in other species, no viral particles were detected. Reverse slot hybridization revealed cross-hybridization between DNA extracted from goat mammary papillomas and human papillomaviruses (HPV). Southern blot, using ovine papillomavirus (OPV) and bovine papillomavirus type 5 (BPV 5) DNA probes under conditions of reduced stringency (Tm -40 degrees C), detected homologous sequences in 40% of the biopsies. DNA fragments corresponding probably to a monomeric form (7000-8000 bp) of an unknown papillomavirus genome were detected. This study provides evidence for the existence of papillomavirus-like sequences in caprine mammary papillomas and suggests that a papillomavirus is likely to be involved in the development of precancerous lesions of goat mammary skin.

Detection of papillomaviral-like DNA sequences in premalignant and malignant perineal lesions of sheep

Small hyperkeratotic and ulcerated lesions and clinical cancers were isolated from the perineal region of sheep and examined for evidence of papillomavirus infection by various criteria including gross morphology, histology, immunohistochemistry and DNA hybridisation. No specific diagnostic features of papillomaviral infection by immunohistochemistry were found, although some lesions showed gross morphological and histological features similar to papillomaviral effect in other species. DNA hybridisation analysis, using human papillomaviral type 11, 13, 16 and 18 DNA probes under conditions of reduced stringency (Tm-40 degrees C), detected homologous sequences in two thirds of the biopsies examined. These homologous sequences occurred in benign hyperkeratosis as well as invasive squamous cell carcinomas but were much more frequently isolated from carcinomas. This finding suggests that a papillomavirus is associated with the development of squamous cell carcinomas of the perineum of sheep.