Phylogenetic and structural studies of a novel equine papillomavirus identified from aural plaques

Papillomaviruses (PVs) infect a wide range of animal species and show great genetic diversity. To date, excluding equine sarcoids, only three species of PVs were identified associated with lesions in horses: Equus caballus papillomavirus 1 (EcPV1-cutaneous), EcPV2 (genital) and EcPV3 (aural plaques). In this study, we identified a novel equine PV from aural plaques, which we designated EcPV4. Cutaneous samples from horses with lesions that were microscopically diagnosed as aural plaques were subjected to DNA extraction, amplification and sequencing. Rolling circle amplification and inverse PCR with specific primers confirmed the presence of an approximately 8 kb circular genome. The full-length EcPV4 L1 major capsid protein sequence has 1488 nucleotides (495 amino acids). EcPV4 had a sequence identity of only 53.3%, 60.2% and 51.7% when compared with the published sequences for EcPV1, EcPV2 and EcPV3, respectively. A Bayesian phylogenetic analysis indicated that EcPV4 clusters with EcPV2, but not with EcPV1 and EcPV3. Using the current PV classification system that is based on the nucleotide sequence of L1, we could not define the genus of the newly identified virus. Therefore, a structural analysis of the L1 protein was carried out to aid in this classification because EcPV4 cause lesion similar to the lesion caused by EcPV3. A comparison of the superficial loops demonstrated a distinct amino acid conservation pattern between EcPV4/EcPV2 and EcPV4/EcPV3. These results demonstrate the presence of a new equine PV species and that structural studies could be useful in the classification of PVs.     

EcPV2 DNA in equine genital squamous cell carcinomas and normal genital mucosa

Squamous cell carcinoma (SCC) represents the most common genital malignant tumor in horses. Similar to humans, papillomaviruses (PVs) have been proposed as etiological agents and recently Equine papillomavirus type 2 (EcPV2) has been identified in a subset of genital SCCs. The goals of this study were (1) to determine the prevalence of EcPV2 DNA in tissue samples from equine genital SCCs, penile intraepithelial neoplasia (PIN) and penile papillomas, using EcPV2-specific PCR, (2) to examine the prevalence of latent EcPV2 infection in healthy genital mucosa and (3) to determine genetic variability within EcPV2 and to disentangle phylogenetic relationships of EcPV2 among PVs. EcPV2 DNA was detected in all but one penile SCC (15/16), in all PIN lesions (8/8) and penile papillomas (4/4). Additionally, EcPV2 DNA was demonstrated in one of two metastasized lymph nodes, one contact metastasis in the mouth, two vaginal and one anal lesion. In healthy horses, EcPV2 DNA was detected in 10% (4/39) of penile swabs but in none of vulvovaginal swabs (0/20). This study confirms the presence of EcPV2 DNA in equine genital SCCs and shows its involvement in anal lesions, a lymph node and contact metastases. Latent EcPV2 presence was also shown in normal male genital mucosa. We found that different EcPV2 variants cocirculate among horses and that EcPV2 is related to the Delta+Zeta PVs and is only a very distant relative of high-risk human PVs causing genital cancer. Thus, similar viral tropism and similar malignant outcome of the infection do not imply close evolutionary relationship.     

Novel betapapillomavirus associated with hand and foot papillomas in a cynomolgus macaque

Betapapillomavirus is a genus of papillomaviruses (PVs) commonly found in human skin and associated with both benign and malignant skin lesions. Only 2 previous beta-PVs have been fully characterized in nonhuman species. This report describes a novel beta-PV, named Macaca fascicularis PV type 2 (MfPV2), isolated from exophytic skin papillomas on the hands and feet of a 2-year-old male cynomolgus monkey (M. fascicularis). On histology the papillomas were composed of diffusely thickened epidermis with superficial foci of cytomegaly, cytoplasmic pallor, marginalized chromatin, and rare eosinophilic intranuclear inclusion bodies. Positive immunostaining for p16 and the proliferation marker Ki67 was present multifocally within affected epidermis, most prominently within basal-type cells. Complete sequence identity (100%) was noted between PV genomes fully sequenced from hand and foot lesions. The MfPV2 genome was 7632 base pairs in length and included putative open reading frames (ORFs) for E1, E2, E4, E6, E7, L1, and L2 genes, similar to other PVs. The closest relatives to MfPV2 based on the L1 ORF sequence were all beta-PVs. These included human PV (HPV) 9, HPV115, HPV76, HPV75, and MfPV1 (60-70% pairwise identity for all), the latter of which was also isolated from hand and foot papillomas in a cynomolgus macaque. Phylogenetic analysis placed MfPV2 in a new species group (beta-6), distinct from HPVs (beta-1 to beta-5) and MfPV1 (beta-1). These findings characterize a new nonhuman beta-PV and provide additional support for the idea that tissue tropism among ancestral primate PVs developed prior to divergence of certain Old World primate lineages.     

Evaluation of equine papillomas, aural plaques, and sarcoids for the presence of Equine papillomavirus DNA and Papillomavirus antigen

Immunohistochemical (IHC) testing and electron microscopy have implicated Papillomavirus (PV) as the etiologic agent for equine papillomas and aural plaques, but Equine papillomavirus (EPV) DNA has yet to be demonstrated in these lesions by polymerase chain reaction (PCR). The purpose of this study was to evaluate formalin-fixed, paraffin-embedded tissues from naturally occurring cases of equine papillomas, aural plaques, and sarcoids for the presence of EPV DNA by means of PCR and for the presence of PV antigen by means of IHC testing. We used EPV-specific primers that amplified a region of 384 base pairs (bp) spanning the E4 and L2 genes of the EPV genome and consensus PV primers that amplified a 102-bp region of the L1 gene. Group-specific PV structural antigens were detected with the use of a streptavidin-biotin-alkaline phosphatase IHC stain. With IHC testing, 23 of 38 papillomas, 4 of 9 aural plaques, and 0 of 10 sarcoids were positive for PV antigen; EPV DNA was found in 20 of the 38 papillomas and 1 of the 10 sarcoids but 0 of the 9 aural plaques. The consensus primers did not amplify novel PV DNA in any of the tissues. Nucleotide sequencing of viral DNA from 7 papillomas amplified with EPV-specific primers revealed DNA fragments that were 96% to 99% identical to known EPV sequences. Some samples had nucleotide substitutions in common, which suggests infection with related strains. Together, EPV DNA or PV antigen (or both) was demonstrated in 26 (68%) of the 38 equine papillomas. Although aural plaques contained PV antigen, they were negative for EPV DNA; therefore, we hypothesize that aural plaques contain a PV distinct from EPV.     

Co-occurrence of papillomas related to Equus caballus papillomavirus type 2 and cutaneous habronemiasis

The present report describes a case of cutaneous papillomatosis related to equine papillomavirus type 2 (EcPV2) with concomitant cutaneous habronemiasis. A 2-year-old female Pura Raza Española horse was referred for a dermatological evaluation because of the onset of cutaneous multifocal, nodular lesions on the face characterised by a warty and partially ulcerated overlying epidermis. Multiple biopsies were taken from these lesions, and cutaneous viral papillomas with a concomitant severe focal eosinophilic dermatitis with intralesional Habronematidae nematode larvae were diagnosed. Immunohistochemistry revealed papillomaviral capsid protein L1 in the epidermal proliferative lesion, confirming the presence of a productive infection. Rt-qPCR confirmed the presence of EcPV type 2. To the authors’ knowledge, this is the first report of EcPV2-related papillomas with concurrent habronemiasis.     

Equus caballus papillomavirus‐2 (EcPV‐2): An infectious cause for equine genital cancer?

Reasons for performing study: The aetiology of genital squamous cell carcinoma (SCC) in horses remains unknown, but the similarity to the disease in man, for which papillomavirus infection has been shown to be a causal factor, requires to be investigated in horses. Hypothesis: One or more novel papillomaviruses cause equine genital SCC and its associated premalignant lesions. Methods: DNA was extracted from samples of equine genital SCC and performed rolling circle amplification, in order to identify closed circular DNA viral genomes within the samples. The amplified DNA was subcloned and sequenced and the DNA sequence compared to that of other papillomavirus genomes. Using PCR primers developed from these genomic DNA sequences, studies were then carried out in order to identify the frequency at which the viral DNA could be identified in equine genital cancer samples from horses in both the UK, Australia and Austria. Finally, in situ hybridisation using specific probes developed from this DNA sequence were used to confirm the presence of the viral RNA sequences in the neoplastic cells in these lesions. Results: The full length genome of a novel papillomavirus species was characterised from the equine genital SCC tissue and termed Equus caballus papillomavirus‐2 (EcPV‐2). Viral DNA and RNA was identified in the genital tumour samples, but not in the adjacent histologically normal tissue. EcPV‐2 DNA could not be identified in equine ocular or nasal carcinomas or within the scrotal skin or in most smegma samples obtained from tumour‐free horses. Sequencing of amplicons, generated from the archived equine genital tumours, identified variations within E1 and E6 on DNA and predicted protein level. Conclusions: A novel papillomavirus, EcPV‐2, is likely to play a causal role in the pathogenesis of equine genital epithelial tumours. Potential relevance: Identification of a papillomavirus causal for genital carcinomas in horses may lead to development of a vaccine that could be used to prevent this serious disease in horses. This would be analogous to man, where vaccination against oncogenic papillomavirus species is currently being used to help prevent cervical cancer.     

Novel papillomavirus isolated from the oral mucosa of a polar bear does not cluster with other papillomaviruses of carnivores

Papillomatosis has been documented in several carnivores, and papillomavirus (PV) types have been characterized from lesions in a number of carnivore species: the canine oral PV (COPV), the Felis domesticus PV type 1 (FdPV-1) isolated from a Persian cat, the Procyon lotor PV type 1 (PlPV-1) isolated from a raccoon, the canine PV type 2 (CPV-2) from a dog's foot pad lesion and the canine PV type 3 (CPV-3) associated with a canine epidermodysplasia verruciformis - like disease. A tissue sample was taken from a papillomatous lesion on the oral mucosa of a polar bear (Ursus maritimus). Extracted DNA was used as a template for multiply primed rolling-circle amplification (RCA), and restriction enzyme analysis of the RCA product indicated the presence of papillomaviral DNA. The genome of this PV was cloned and the complete genomic sequence was determined. The Ursus maritimus PV type 1 (UmPV-1) genome counts 7582 basepairs and is smaller than that of other papillomaviruses from carnivore species. UmPV-1 contains the typical noncoding region NCR1, but unlike the carnivore PVs of the Lambda genus, UmPV-1 does not possess a second noncoding region NCR2. Phylogenetic analysis based on a nucleotide sequence alignment of the L1 ORF of UmPV-1 and 51 other PV types indicates that UmPV-1 does not cluster with any of the other carnivore PVs, but branches off near the root of the common branch of the genus Alphapapillomavirus.     

Feline papillomas and papillomaviruses

Papillomaviruses (PVs) are highly species- and site-specific pathogens of stratified squamous epithelium. Although PV infections in the various Felidae are rarely reported, we identified productive infections in six cat species. PV-induced proliferative skin or mucous membrane lesions were confirmed by immunohistochemical screening for papillomavirus-specific capsid antigens. Seven monoclonal antibodies, each of which reacts with an immunodominant antigenic determinant of the bovine papillomavirus L1 gene product, revealed that feline PV capsid epitopes were conserved to various degrees. This battery of monoclonal antibodies established differential expression patterns among cutaneous and oral PVs of snow leopards and domestic cats, suggesting that they represent distinct viruses. Clinically, the lesions in all species and anatomic sites were locally extensive and frequently multiple. Histologically, the areas of epidermal hyperplasia were flat with a similarity to benign tumors induced by cutaneotropic, carcinogenic PVs in immunosuppressed human patients. Limited restriction endonuclease analyses of viral genomic DNA confirmed the variability among three viral genomes recovered from available frozen tissue. Because most previous PV isolates have been species specific, these studies suggest that at least eight different cat papillomaviruses infect the oral cavity (tentative designations: Asian lion, Panthera leo, P1PV; snow leopard, Panthera uncia, PuPV-1; bobcat, Felis rufus, FrPV; Florida panther, Felis concolor, FcPV; clouded leopard, Neofelis nebulosa, NnPV; and domestic cat, Felis domesticus, FdPV-2) or skin (domestic cat, F. domesticus, FdPV-1; and snow leopard, P. uncia, PuPV-2).     

Canine inverted papillomas associated with DNA of four different papillomaviruses

Inverted papillomas are uncommon papillomavirus (PV)‐induced canine skin lesions. They consist of cup‐ to dome‐shaped dermal nodules with a central pore filled with keratin. Histologically they are characterized by endophytic projections of the epidermis extending into dermis. Cytopathic effects of PVs infection include the presence of clumped keratohyalin granules, koilocytes and intranuclear inclusion bodies. Different DNA hybridization studies carried out with a canine oral papillomavirus (COPV) probe suggested that a different PV than COPV might cause these lesions. Canine papillomavirus 2 (CPV2) was discovered a few years ago in inverted papillomas of immunosuppressed beagles. Two other cases, presenting with distinct clinical and histological features have also been described. This study was carried out on four dogs with clinical and histological signs of inverted papillomas. Molecular biological analyses confirmed that PV DNA was present in all four lesions but demonstrated that the sequences in each case were different. One corresponded to COPV, the second to CPV2, and the third and fourth to unknown PVs. These findings suggest that inverted papillomas are not caused by one single PV type. Similar observations have also been made in human medicine.     

Genetic characterization of the first chiropteran papillomavirus, isolated from a basosquamous carcinoma in an Egyptian fruit bat: the Rousettus aegyptiacus papillomavirus type 1

The complete genomic DNA of a novel papillomavirus (PV) was isolated from a basosquamous carcinoma on the wing of an Egyptian fruit bat (Rousettus aegyptiacus). Initial short sequences of the E1 and L1 genes of this virus were retrieved by PCR with degenerate papillomavirus-specific primers, and the entire R. aegyptiacus papillomavirus type 1 (RaPV-1) DNA was then amplified by long template PCR, cloned and sequenced with a transposon insertion method. The RaPV-1 genome counts 7970 basepairs and contains the typical papillomavirus open reading frames (ORF) (E1, E2, E4, E6, E7, L1 and L2). Based on a concatenated alignment of the E1, E2, L1 and L2 open reading frames of RaPV-1 and 46 other human and animal papillomavirus type species, a neighbor-joining phylogenetic tree was constructed. This phylogenetic analysis shows that RaPV-1 has a close-to-root position in the papillomavirus evolutionary tree. Since RaPV-1 is only distantly related to other papillomaviruses (with maximally 50% nucleotide sequence identity across the L1 open reading frame), it cannot be assigned to one of the existing papillomavirus genera and therefore represents the first member of a novel, as yet unnamed, close-to-root papillomavirus genus. This is the first time a papillomavirus has been isolated and characterized from a member of the Chiroptera order.     

牛乳头瘤病毒基因1型广西GX01流行株全基因组克隆及序列分析

为了解牛乳头瘤病毒1型（bovine papillomavirus genotype 1,BPV-1）广西GX01株全基因组序列、结构特征及遗传变异情况,同时了解该毒株引起宿主产生的病理组织学变化情况,本研究选取广西贺州市患病牛皮肤肿瘤样物制作石蜡切片后镜检观察,提取病料DNA,以乳头瘤病毒L1基因的简并引物FAP59/FAP64进行PCR扩增以确定此病毒的基因型,根据GenBank中BPV参考株设计嵌套引物,对GX01株进行全基因组扩增、克隆测序及序列分析。病理组织学检查结果显示,可在病变部位发现表皮细胞增生、肿胀,角质过度及挖空细胞等乳头瘤病毒感染的特征性病变。序列分析结果表明,GX01株为BPV-1,其全基因组长为7 945 bp,包含E1、E2、E4、E5、E6、E7、L1、L2 8个开放阅读框,符合BPV-1型基因组的结构特征;GX01与BPV-1参考株全基因组核苷酸序列同源性为98.6%~99.6%,与BPV-2型参考株（M20219.1）、BPV-13型参考株（JQ798171.1）同源性分别为86.9%和87.2%。GX01株为广西地区首次经检测确认并测定全基因组序列的牛乳头瘤病毒。本研究为广西地区乃至全国的牛乳头状瘤的病原鉴定、流行规律、遗传变异、疫源追溯及科学防控提供了基础数据。     

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

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

Detection of papillomavirus-DNA in mesenchymal tumour cells and not in the hyperplastic epithelium of feline sarcoids

Abstract We examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (PV) DNA using touchdown polymerase chain recation (PCR), DNA sequencing and nonradioactive in situ hybridization. Nine of the tumours contained a 102-bp PCR product demonstrated using consensus PV primers that amplify a portion of the L1 gene. The nucleotide sequences are closely related, but not identical to that of ovine PV type 2, rabbit oral PV and reindeer PV. The deduced amino acid sequences had strong homologies with the major capsid protein L1 of deer PV, bovine papillomavirus (BPV) 1 and BPV 2, and European elk PV. Although PV antigens were not detected in any of the tumours by immunohistochemistry, PV DNA was demonstrated in individual mesenchymal cells or cell nests of 4/12 tumours by in situ hybridization. A nonproductive infection of mesenchymal fibroblast-like tumour cells with a papillomavirus would explain the lack of PV antigen expression and the absence of PV DNA in the hyperplastic epithelium. Because these tumours and their pathogenesis are similar to equine sarcoids, we suggest that they should be reclassified as 'feline sarcoids' instead of fibropapillomas.     

Detection of canine oral papillomavirus-DNA in canine oral squamous cell carcinomas and p53 overexpressing skin papillomas of the dog using the polymerase chain reaction and non-radioactive in situ hybridization

Nineteen cutaneous and mucocutaneous papillomas, as well as 29 oral and 25 non-oral squamous cell carcinomas of dogs were analyzed immunohistologically for the presence of papillomavirus (PV)-antigens. Canine oral papillomavirus (COPV)-DNA was detected in formalin-fixed, paraffin-embedded tissues by polymerase chain reaction (PCR) and non-radioactive in situ hybridization (ISH). Furthermore, the expression of the tumor suppressor protein p53 was investigated. PV-antigens were detectable in more than 50% of the oral and cutaneous papillomas, while no PV-antigens could be demonstrated in venereal papillomas. One squamous cell carcinoma was PV-antigen positive. Only two cutaneous papillomas of the head showed a strong p53-specific immunostaining, while overexpressed p53 was detectable in approximately 35% of all squamous cell carcinomas. It was possible to amplify fragments of the E6, E7 and L1 gene by polymerase chain reaction (PCR) from five of eight oral and from five of eight cutaneous papillomas as well as from three oral squamous cell carcinomas. Nine of 10 papillomas showed a strong nucleus-associated hybridization signal typical for COPV-DNA. In three squamous cell carcinomas COPV-DNA was located in nests of the epithelial tumor cells surrounding ‘horn pearls' or disseminated in the carcinoma tissue. These observations support the view that COPV may also induce non-oral papillomas in the dog and confirm the opinion that a progression of viral papillomas into carcinomas in dogs may occur.     

Investigation of parrot papillomavirus in cloacal and oral papillomas of psittacine birds

Cloacal and oral papillomas from 27 psittacine birds of various species were examined for the presence of parrot papillomavirus by DNA in situ hybridization, DNA in situ polymerase chain reaction, and nested polymerase chain reaction. Parrot papillomavirus was detected in one oral papilloma from an African grey parrot by all three techniques. In addition, rare basophilic intranuclear inclusions were observed by light microscopy in tissue sections of the oral papilloma from this parrot. The remaining lesions were negative for parrot papillomavirus DNA. This study suggests that parrot papillomavirus may be involved in the development of papillomas in African grey parrots, but apparently is not responsible for development of similar lesions in unrelated species of psittacine birds.     

Detection of novel papillomaviruses in canine mucosal, cutaneous and in situ squamous cell carcinomas

Papillomavirus (PV) DNA is frequently uncovered in samples of human skin squamous cell carcinomas (SCC). However, the role of these viruses in the development of such cancers in canine species remains controversial. While approximately 100 human PVs are known, only one single canine oral PV (COPV) has been identified and studied extensively. Therefore, we applied a narrow-range polymerase chain reaction (PCR) suitable for the detection of classical canine and feline PVs, as well as a broad-range PCR, which has been used for the detection of various novel PVs in humans, in order to analyse 42 paraffin-embedded samples, representing three different forms of canine SCCs. Ten samples of skin tissues with various non-neoplastic conditions served as controls. While none of the negative controls reacted positively, PV DNA was discovered in 21% of the tested SCC samples. Interestingly, the classical COPV was amplified from only one sample, while the other positive cases were associated with a variety of thus far unknown PVs. This study suggests that a fraction of canine SCC is infected with PVs and that a genetic variety of canine PVs exists. Therefore, these results will facilitate the future study of the role of PVs in the development of canine skin cancers.     

Detection of novel papillomaviruslike sequences in paraffin-embedded specimens of invasive and in situ squamous cell carcinomas from cats

OBJECTIVE: To detect and partially characterize papillomavirus (PV) DNA in squamous cell carcinoma (SCC) tumor specimens from cats. SAMPLE POPULATION: 54 formalin-fixed paraffinembedded skin biopsy specimens were examined. Specimens originated from Bowenoid in situ SCC (BISC; n = 21), invasive SCC (22), and skin affected by miscellaneous nonneoplastic conditions (11). PROCEDURES: Samples from each tissue block underwent DNA extraction after deparaffinization, and PCR assays were performed. Two sets of primers derived from PV E1 were used. The first set of primers was designed for the narrow-range PCR assay and was able to generate amplification products of feline PV (FePV), canine oral PV, or closely related PVs. The second set of primers was selected for the broad-range PCR assay because of its ability to amplify DNA from 64 human PVs. Sequence analysis of each amplified DNA was performed. RESULTS: 1 of the 21 specimens of BISC was positive for PV DNA on the basis of narrow-range PCR assay results, whereas all the other specimens (BISC, invasive SCC, and controls) had negative results for PV DNA. In contrast, 5 of 21 BISC specimens and 4 of 22 invasive SCC specimens were positive for PV DNA on the basis of broad-range PCR assay results. Sequence analysis revealed that only 1 specimen was infected by a virus closely related to classic FePV. In the 8 other specimens positive for PV DNA, DNA of unknown PVs was uncovered. CONCLUSIONS AND CLINICAL RELEVANCE: Bowenoid in situ SCC and invasive SCC of cats may be associated with PVs of genetic diversity.     

Detection of papillomaviral DNA sequences in a feline oral squamous cell carcinoma

Oral squamous cell carcinomas (OSCCs) are common and often fatal feline neoplasms. Factors that predispose to neoplasm development in cats are poorly defined. Around 25% of human OSCCs are caused by papillomaviruses (PVs). To determine if PVs are associated with OSCCs in cats, three sets of consensus primers were used to evaluate 20 feline OSCCs and 20 non-neoplastic feline oral lesions for the presence of PV DNA. Papillomaviral sequences were detected within one OSCC, but no non-neoplastic lesion. Sequencing of the amplified DNA revealed a previously unreported PV that was most similar to human PV type 76. This is the first time PV DNA has been amplified from the oral cavity of a cat. However, while these results suggest that feline gingival epithelial cells can be infected by PVs, they do not support a causal association between viral infection and the development of feline OSCCs.     

猪繁殖与呼吸综合征病毒国内分离经典株与变异株的全基因组序列分析

通过分段设计引物,对猪繁殖与呼吸综合征病毒(PRRSV)LX、JX株基因组进行RT-PCR扩增,对各片段cDNA进行克隆和序列测定,拼接后获得全基因组序列。结果,PRRSV LX株全基因组序列长度为15 412 bp(不包括PolyA尾),PRRSV JX株全基因组序列长度为15 320 bp(不包括PolyA尾)。序列分析表明,JX株全基因组核苷酸序列与LX株、JXA1、VR2332、CH-1a、BJ-4、LV同源性分别为91.1%、98.6%、91.0%、94.6%、90.9%、61.7%;LX株全基因组核苷酸序列与JX株、JXA1、VR2332、CH-1a、BJ-4、LV同源性分别为91.1%、89.7%、99.7%、91.5%、99.7%、62.2%。对不同分离株的5′-UTR、Nsp2进行了序列比较,并根据5′-UTR、Nsp2、ORF5的基因序列和氨基酸序列,对国内外分离株进行了系统进化分析。根据5′-UTR核苷酸序列,可将PRRSV美洲型毒株分为4个亚群,LX株和JX株分别属于经典美洲型和"高热病"变异型。根据Nsp2氨基酸序列分析了不同分离株的分子进化关系,表明依据Nsp2序列美洲型分离株可初步划分为5个亚群,JX株独立于其他毒株,独自处于一个分支。依据ORF5序列也可将美洲型分离株划分为5个亚群。本研究为探讨PRRSV的分子进化奠定了基础。     

Cloacal papillomas in psittacines

Papilloma-like masses affecting the cloaca of 19 Amazons, 16 macaws, 3 parrots, 1 conure, and 1 parakeet were examined. Papillomatous lesions were characterized by proliferation of the lining epithelium on thin fibrovascular stalks. Carcinoma in situ was diagnosed in the cloaca of a macaw in addition to the other 16 macaws with papillomas. Papillomavirus group-specific antigens were not detected in any of the 41 lesions, using the peroxidase-antiperoxidase technique. The DNA extracts from 6 different frozen papillomas did not contain papillomavirus genomes detectable by Southern blot hybridization, using an African gray parrot cutaneous papillomavirus as a probe. Evidence of an infective agent was not found by electron microscopic examination of 8 of the papillomas. Inoculations of partially purified homogenates of a cloacal papilloma from a yellow-crowned Amazon did not induce lesion formation on cloacal mucosa of an adult yellow-crowned Amazon, green and yellow macaw, sulphur-crested cockatoo, or mollucan cockatoo.