Epidemiology of molluscum contagiosum using genetic analysis of the viral DNA

Comprehensive analysis of 66 complete molluscum contagiosum virus (MOCV) genomes: characterization and functional annotation of 47 novel complete MOCV genomes, including the first genome of MOCV genotype 3, and a proposal for harmonized MOCV genotyping indexing

IMPORTANCE

Four molluscum contagiosum virus (MOCV) genotypes (MOCV1-4) and four subtype variants were partially characterized using restriction enzyme profiling in the 1980s/1990s, but complete genome sequences of only MOCV1 and MOCV2 are available. The evolutionary pathways whereby genotypes/subtype variants with unavailable sequences emerged and whether all MOCVs can be detected using current diagnostic approaches remain unclear. We fully characterized 47 novel complete MOCV genomes, including the first complete MOCV3 genome, expanding the number of fully characterized genomes to 66. For reliably classifying the novel non-MOCV1/2 genomes, we developed and validated a framework for matching sequence-derived restriction maps with those defining MOCV subtypes in pioneering studies. Six phylogenetic subgroups (PG1-6) were identified, PG5 representing a novel MOCV2 subtype. The phylogenetic subgroups diverged from the prototype lineages following large-scale recombination events and hinted at partial sequence content of MOCV4 and direction of recombinant transfer in the events spawning PG5 and yet undetected MOCV1vb variant.

Arctigenin inhibits prostate tumor growth in high-fat diet fed mice through dual actions on adipose tissue and tumor

This study investigated the inhibitory effect of arctigenin, a novel anti-inflammatory lignan, on prostate cancer in obese conditions both in vitro and in vivo. In vitro obese models were established by co-culture of mouse adipocytes 3T3-L1 with androgen-sensitive LNCaP human prostate cancer cells, or by culturing LNCaP cells in adipocytes-conditioned medium. Arctigenin significantly inhibited LNCaP proliferation, along with decreased androgen receptor (AR) and increased Nkx3.1 cellular expression. Male severe combined immunodeficiency mice were subcutaneously implanted with human prostate cancer LAPC-4 xenograft tumors for in vivo study. Mice were fed high-fat (HF) diet and orally given arctigenin at 50 mg/kg body weight daily or vehicle control for 6 weeks. Tumor bearing HF control mice showed a significant increase in serum free fatty acids (FFAs) and decrease in subcutaneous/peritoneal fat depots compared to non-tumor bearing control mice. Arctigenin intervention significantly reduced tumor growth by 45%, associated with decreased circulating FFAs and adipokines/cytokines including IGF-1, VEGF, and MCP-1, along with decreased AR, Ki67, and microvessel density and increased Nkx3.1 expression in tumors. These results indicate the strong ability of arctigenin to co-target obesity and tumor itself in inhibition of prostate tumor growth at a lower concentration compared to most phytochemicals.

Clinical, Histopathological, and Virological Evaluation of 203 Patients With a Clinical Diagnosis of Molluscum Contagiosum

Molluscum contagiosum (MC) manifests as small, umbilicated papules caused by the molluscum contagiosum virus (MCV). The extent of clinical misdiagnosis of MC is unknown. Combined clinical, histopathological, and virological evaluation of 203 consecutive patients with clinical diagnosis of MC treated at a university hospital during a 5-year period showed the correct clinical diagnosis in 188 of 203 (92.6%) patients. All 15 clinically misdiagnosed MC lesions were histopathologically and virologically confirmed as either common or anogenital warts caused by different human papillomaviruses. The MCV1/MCV2 subtypes ratio was 1.54:1, and the distribution of MCV subtypes differed across patients’ age and anatomical location of lesions.

New Insights into the Evolutionary and Genomic Landscape of Molluscum Contagiosum Virus (MCV) based on Nine MCV1 and Six MCV2 Complete Genome Sequences

Molluscum contagiosum virus (MCV) is the sole member of the Molluscipoxvirus genus and the causative agent of molluscum contagiosum (MC), a common skin disease. Although it is an important and frequent human pathogen, its genetic landscape and evolutionary history remain largely unknown. In this study, ten novel complete MCV genome sequences of the two most common MCV genotypes were determined (five MCV1 and five MCV2 sequences) and analyzed together with all MCV complete genomes previously deposited in freely accessible sequence repositories (four MCV1 and a single MCV2). In comparison to MCV1, a higher degree of nucleotide sequence conservation was observed among MCV2 genomes. Large-scale recombination events were identified in two newly assembled MCV1 genomes and one MCV2 genome. One recombination event was located in a newly identified recombinant region of the viral genome, and all previously described recombinant regions were re-identified in at least one novel MCV genome. MCV genes comprising the identified recombinant segments have been previously associated with viral interference with host T-cell and NK-cell immune responses. In conclusion, the two most common MCV genotypes emerged along divergent evolutionary pathways from a common ancestor, and the differences in the heterogeneity of MCV1 and MCV2 populations may be attributed to the strictness of the constraints imposed by the host immune response.

Periocular molluscum contagiosum: six different clinical presentations

PURPOSE

To describe the different clinical presentations of periocular molluscum contagiosum (MC) lesions and their epidemiological, clinical and histopathological features.

METHODS

Medical records and histopathological sections of all cases of periocular MC treated at the oculoplastic clinic of the Goldschleger Eye Institute, Sheba Medical Center, Israel, between 1995 and 2016 were retrospectively reviewed. The following data were extracted: gender, age at the time of MC diagnosis, immune competency, location of the periocular lesions, number of lesions, dimensions of the lesions, clinical presentation, histopathological features, suspected clinical diagnosis before histopathological diagnosis and treatment.

RESULTS

The series was composed of 41 patients (19 males, 22 females) whose mean age at presentation was 20.41  ±  21.10 years (range 1-71 years). Only one patient was immunosuppressed. The cases were classified into six proposed clinical presentations: 'umbilicated nodular', 'big/giant', 'conglomerated', 'erythematous', 'inflamed' and 'pedunculated'.

CONCLUSION

This is the first time that different clinical types of MC lesions are labelled. The current evidence also indicates that MC lesions should be suspected not only in children and in immunosuppressed adult patients but also in immunocompetent patients of all ages.

Recombination events and variability among full-length genomes of co-circulating molluscum contagiosum virus subtypes 1 and 2

Molluscum contagiosum virus (MCV) is the sole member of the Molluscipoxvirus genus and causes a highly prevalent human disease of the skin characterized by the formation of a variable number of lesions that can persist for prolonged periods of time. Two major genotypes, subtype 1 and subtype 2, are recognized, although currently only a single complete genomic sequence corresponding to MCV subtype 1 is available. Using next-generation sequencing techniques, we report the complete genomic sequence of four new MCV isolates, including the first one derived from a subtype 2. Comparisons suggest a relatively distant evolutionary split between both MCV subtypes. Further, our data illustrate concurrent circulation of distinct viruses within a population and reveal the existence of recombination events among them. These results help identify a set of MCV genes with potentially relevant roles in molluscum contagiosum epidemiology and pathogenesis.

Molluscum contagiosum: to treat or not to treat? Experience with 170 children in an outpatient clinic setting in the northeastern United States

Despite the high prevalence of molluscum contagiosum (MC) in children, epidemiologic data on this common self-limited viral infection is limited. In this report we review our experience with the demographic characteristics, clinical characteristics, management, and time to resolution of MC in 170 children. A retrospective medical chart review and telephone survey were conducted on children younger than 16 years of age evaluated for MC in the Division of Pediatric Dermatology at the Johns Hopkins Children's Center, Baltimore, Maryland, from January 1, 2008, to December 31, 2011. Of 170 children with MC, 51.8% were female and 77.1% were Caucasian. The median age at diagnosis was 5 years and 46.5% had a history of atopic dermatitis (AD). Children with AD had significantly more MC lesions than those without (p < 0.05); 72.9% of children did not receive any treatment. MC lesions completely cleared within 12 months in 45.6% of treated and 48.4% of untreated children and within 18 months in 69.5% of treated and 72.6% of untreated children. Treatment (if any), sex, race, diagnosing physician, number of lesions at diagnosis, number of anatomic locations, or history of AD did not predict time to resolution of MC lesions. MC lesions completely resolved in approximately 50% of children within 12 months and in 70% within 18 months. Treatment did not shorten the time to resolution.

Beetle juice: a guide for the use of cantharidin in the treatment of molluscum contagiosum

Molluscum contagiosum (MC) is an increasingly common cutaneous viral infection that primarily affects the pediatric population. MC lesions are benign, and most cases resolve within 6-9 months. Nonetheless, many patients and their parents seek active treatment of MC because of local pain, pruritus, embarrassment due to the lesions, or desire to reduce transmission to siblings. Individuals with atopic dermatitis are predisposed to severe and protracted MC, and immunocompromised patients may never clear the infection without treatment. Despite the availability of various therapies, no clear best treatment for MC has emerged. Cantharidin is a commonly used and effective therapy for MC that is generally well tolerated and has high rates of parental satisfaction. In this review, current literature regarding MC is summarized and particular focus is placed on the use of cantharidin for treating MC, including a review of the literature and detailed instructions for its use.

Molluscum contagiosum virus infection

Molluscum contagiosum virus is an important human skin pathogen: it can cause disfigurement and suffering in children, in adults it is less common and often sexually transmitted. Extensive and persistent skin infection with the virus can indicate underlying immunodeficiency. Traditional ablative therapies have not been compared directly with newer immune-modulating and specific antiviral therapies. Advances in research raise the prospect of new approaches to treatment informed by the biology of the virus; in human skin, the infection is localised in the epidermal layers, where it induces a typical, complex hyperproliferative lesion with an abundance of virus particles but a conspicuous absence of immune effectors. Functional studies of the viral genome have revealed effects on cellular pathways involved in the cell cycle, innate immunity, inflammation, and cell death. Extensive lesions caused by molluscum contagiosum can occur in patients with DOCK8 deficiency-a genetic disorder affecting migration of dendritic and specialised T cells in skin. Sudden disappearance of lesions is the consequence of a vigorous immune response in healthy people. Further study of the unique features of infection with molluscum contagiosum virus could give fundamental insight into the nature of skin immunity.

Rapid detection and typing of Molluscum contagiosum virus by FRET-based real-time PCR

A fluorescence resonance energy transfer (FRET)-based real-time PCR (RT-PCR) was developed for very sensitive and specific detection of Molluscum contagiosum virus (MCV), as well as reliable differentiation of the two MCV subtype genetic lineages, MCV1 and MCV2, in a single reaction. The assay employs modified primers specific for the viral MC021L gene and uses two novel FRET hybridization probes to detect polymorphisms specific for each of the two subtypes. The sensitivity of the assay at a 95% detection level for both MCV subtypes was 3.3 DNA copies/reaction and the dynamic range was nine orders of magnitude, discriminating 10-10(9) viral genome equivalents/reaction. Post-amplification probe-specific dissociation analysis differentiated the two viral subtypes reliably in all tested concentrations. Testing of 43 tissue specimens clinically diagnosed as MCV lesions showed complete agreement with the results obtained with previously described MCV specific MC080R Taqman RT-PCR and MC021L whole gene sequencing. The novel assay is simple, robust and easy to perform, and may be of great value for clinical and epidemiological studies of MCV infections and related conditions.

Clinical characteristics of molluscum contagiosum in children in a private dermatology practice in the greater Paris area, France: a prospective study in 661 patients

BACKGROUND

Series regarding the clinical characteristics of molluscum contagiosum (MC) are retrospective and concern small defined populations seen in a hospital setting.

METHODS

We prospectively studied patients under 15 years of age with MC seen in 25 private dermatology practices in the greater Paris area during 1 year.

RESULTS

Six hundred fifty patients were included. The mean age was 6 years. Of the patients, 30.5% had had MC in the past, 53% had 5-20 MC, 43% had a history of atopic dermatitis (AD), 5% were using topical steroids, 25.5% had coexistent AD, 13% had giant MC (>5 mm), 21% had inflammatory MC, and 19% had MC surrounded by eczema. Bathing with siblings was associated with a higher number of MC. A history of AD was associated with the presence of MC surrounded by eczema. The use of topical steroids was associated with a higher risk of relapse. There was no relation between environmental factors (MC in surrounding people, going to the swimming pool, sports practice) and the number of lesions or between environmental factors and the number of recurrences.

CONCLUSION

Atypical lesions are frequent. Bathing with siblings is associated with a higher number of MC. Topical steroid use increases the risk of relapses. AD prevalence is higher than in the general population.

Congenital molluscum contagiosum: report of four cases and review of the literature

Molluscum contagiosum is a viral infection of the skin and mucous membranes that is caused by infection with the molluscum contagiosum virus. Molluscum contagiosum can be acquired from skin to skin contact which may be during play, in a swimming pool, or through sexual contact. Sexually acquired molluscum is rare in younger children, but becomes quite common during adolescence and young adulthood, after the sexual debut. It has been long known that the human papillomavirus, which causes genital warts, i.e., condyloma accuminatum, can be vertically transmitted through an infected genital tract. Children may not manifest condyloma lesions for a few years. The entity of congenital molluscum has been debated in the literature and only three cases of suspected congenital molluscum have been reported. We report on four more infants with congenital molluscum, two children with congenital lesions, and two children with onset of lesions at 6 weeks of age. Two children had single cutaneous lesions on the extremities and two had lesions of the scalp consistent with the site of cervical pressure. Congenital molluscum appears to be a more common entity than previously reported. Vertical transmission of molluscum should be considered for all infantile cases of molluscum.

Fast and reliable diagnostic methods for the detection of human poxvirus infections

Although the most prominent poxvirus, Variola virus, was successfully eradicated in the last century, several other poxviruses cause zoonotic infections that, in the early stages, resemble Variola virus infections with varying pathogenicity in humans. Over recent decades, numerous diagnostic methods for the detection of poxviruses have been established. As a result of technical progress and the advancement in molecular techniques, only a small selection of these methods meet the demands of being rapid and reliable. This review briefly introduces human poxviruses, summarizes the methods available, discusses their pros and cons and provides recommendations for a ‘fast and reliable diagnostic approach.

The epidemiology of molluscum contagiosum in children

Molluscum contagiosum (MC) is a viral disorder of the skin and mucous membranes characterized by discrete single or multiple, flesh-colored papules. Although MC as a clinical entity is well defined and commonly observed, few data regarding its epidemiology in the pediatric population exist. Our purpose was to collect epidemiologic data on children with MC with regard to age, gender, ethnicity, degree of involvement, relation to pre-existing atopic dermatitis (AD), and immune status. A retrospective chart review was conducted. All subjects were seen at 3 tertiary pediatric dermatology referral centers with two of the sites based at a Children's Hospital. A total of 302 patient charts with the Current Procedural Terminology code diagnosis of MC seen over a 6- to 8-month period were reviewed. Approximately 80% of the patients were younger than 8 years old. The majority of patients (63%) had more than 15 lesions. All but one patient were otherwise healthy, as determined by history and clinical examination. Approximately 24% of the patients presented with a history of previous or active coexistent AD. However, children with AD were at risk for an increased number of lesions. These data provide valuable updated information on the demographics and clinical presentation of MC in pediatric patients in the United States. Limitations include that this was a retrospective study with a population limited to tertiary pediatric dermatology referral centers.

Molluscum contagiosum: the importance of early diagnosis and treatment

Molluscum contagiosum is a viral infection that is becoming an increasing problem in sexually active individuals and in patients with human immunodeficiency virus. Although molluscum contagiosum lesions are generally self-limiting, it may take 6 months to 5 years for lesions to disappear. Furthermore, patients with weakened immune systems have increased difficulty in clearing lesions; therefore lesions typically persist for prolonged periods. Although there has been continued debate about whether molluscum contagiosum lesions should be treated or allowed to resolve spontaneously, many clinicians recommend treatment of genital molluscum contagiosum lesions to reduce the risk of sexual transmission, prevent autoinoculation, and increase patient quality of life. Treatment options for molluscum contagiosum include physician-administered and patient-administered therapies. Novel patient-administered treatment options allow administration in the privacy of a patient's home, providing added convenience and reducing patient embarrassment or stress. With the novel treatment opportunities currently available or in development, physicians are able to improve patient quality of life while providing patients with a convenient, well-tolerated, easily administered treatment regimen. This review summarizes the clinical diagnosis of molluscum contagiosum and provides a critical assessment of several current and emerging treatment options.

An overview of poxviruses

The poxvirus family is a diverse and interesting group of viruses that affect both humans and animals. Poxviruses are epitheliotropic and therefore are of interest to the dermatologist. The genera of poxviruses known to affect humans are Orthopoxvirus, Parapoxvirus, Molluscipoxvirus, and Yatapoxvirus. The different poxviruses are reviewed, including their history, incidence, clinical presentation, and treatment.

The genome of molluscum contagiosum virus: analysis and comparison with other poxviruses

Analysis of the molluscum contagiosum virus (MCV) genome revealed that it encodes approximately 182 proteins, 105 of which have direct counterparts in orthopoxviruses (OPV). The corresponding OPV proteins comprise those known to be essential for replication as well as many that are still uncharacterized, including 2 of less than 60 amino acids that had not been previously noted. The OPV proteins most highly conserved in MCV are involved in transcription; the least conserved include membrane glycoproteins. Twenty of the MCV proteins with OPV counterparts also have cellular homologs and additional MCV proteins have conserved functional motifs. Of the 77 predicted MCV proteins without OPV counterparts, 10 have similarity to other MCV proteins and/or distant similarity to proteins of other poxviruses and 16 have cellular homologs including some predicted to antagonize host defenses. Clustering poxvirus proteins by sequence similarity revealed 3 unique MCV gene families and 8 families that are conserved in MCV and OPV. Two unique families contain putative membrane receptors; the third includes 2 proteins, each containing 2 DED apoptosis signal transduction domains. Additional families with conserved patterns of cysteines and putative redox active centers were identified. Promoters, transcription termination signals, and DNA concatemer resolution sequences are highly conserved in MCV and OPV. Phylogenetic analysis suggested that MCV, OPV, and leporipoxviruses radiated from a common poxvirus ancestor after the divergence of avipoxviruses. Despite the acquisition of unique genes for host interactions and changes in GC content, the physical order and regulation of essential ancestral poxvirus genes have been largely conserved in MCV and OPV.

Recent advances in molluscum contagiosum virus research

Molluscum contagiosum virus (MCV) and variola virus (VAR) are the only two poxviruses that are specific for man. MCV causes skin tumors in humans and primarily in children and immunocompromised individuals. MCV is unable to replicate in tissue culture cells or animals. Recently, the DNA sequence of the 190 kbp MCV genome was reported by Senkevich et al. MCV was predicted to encode 163 proteins of which 103 were clearly related to those of smallpox virus. In contrast, it was found that MCV lacks 83 genes of VAR, including those involved in the suppression of the host response to infection, nucleotide biosynthesis, and cell proliferation. However, MCV possesses 59 genes predicted to code for novel proteins including MHC-class I, chemokine and glutathione peroxidase homologs not found in other poxviruses. The MCV genomic data allow the investigation of novel host defense mechanisms and provide new possibilities for the development of therapeutics for treatment and prevention of the MCV infection.

Successful treatment of molluscum contagiosum in the immunosuppressed adult with topical injection of streptococcal preparation OK-432

A 37-year-old Japanese woman received an anticancer drug for 5 years following resection of mammary cancer and then developed widespread mollusca contagiosa, which we considered to be caused by immunosuppression induced by the chemotherapy. Because OK-432 (penicillin-treated and heat-treated lyophilized powder by a substrain of Streptococcus pyogenes A) was expected to be effective for immunosuppression, we tried its topical injection. The skin lesions disappeared almost completely within three months. OK-432 therapy is considered hopeful for treating viral skin diseases, even in immunosuppressed patients.

Molecular epidemiologic analysis of Japanese patients with molluscum contagiosum

BACKGROUND

Molluscum contagiosum virus (MCV) causes molluscum contagiosum (MC) in both children and adults. Recent studies have revealed that the DNA of MCV can be classified into two major types by restriction enzyme cleavage patterns; however, the relationship between MCV types and the clinical features has not been fully understood. Our study was conducted to examine whether there are geographic differences in the incidence of MCV types and whether a correlation exists between MCV types and the age, sex, and clinical status of the patients.

METHODS

Specimens were obtained from 171 Japanese patients. The total DNA was extracted and digested with the restriction enzymes, BamH I, Hind III, and Cla I, respectively. Specimens were then electrophoresed in agarose gels. The gels were stained with ethidium bromide and photographs were taken under transillumination.

RESULTS

Six different cleavage patterns were observed; they were classified into two major types, MCV 1 and MCV 2, consisting of two MCV 1-variants, and MCV 2 prototype, and three MCV 2-variants. The ratio of MCV 1 to MCV 2 was 13:1. MCV 1 was commonly detected in children (98%) and adult women (92%). MCV 2 was more frequently isolated from adult men (44%) and from patients with human immunodeficiency virus (HIV) infection (75%).

CONCLUSION

MCV types found in Japanese children and adult women were predominantly MCV 1 and less frequently MCV 2. This pattern is similar to that observed in European countries and Australia, suggesting a high frequency and world-wide distribution of MCV 1. The higher incidence of MCV 2 among adult men and HIV-positive patients may indicate that transmission routes of MCV 1 and MCV 2 is somewhat different, of which the latter may be in part by sexual contact.

Giant molluscum contagiosum in AIDS

A 31-year-old man, an intravenous drug user and in an advanced stage of acquired immune deficiency syndrome (AIDS), was admitted in our Department for the treatment of skin lesions that had been diagnosed as molluscum contagiosum (MC). The clinical examination revealed the presence of multiple nodular lesions, some of which were notably large and whose color resembled that of normal skin. These lesions were localized mainly to the face, and in particular on the forehead, glabellar, malar, beard, submandibular, and neck regions (Fig. 1). Smaller, crateriform lesions were detected on the hands and the upper limbs. The lymphocyte subsets ratio was 0.02, with a CD4+ T cell count of 13 cells per mm3 (1%) and a CD8+ T cell count of 624 per mm3 (48%). The patient also had leukopenia (1690 WBC per mm3), moderate macrocytic anemia, elevation of transaminases (SGOT 105 U/L, SGPT 114 U/L) and of immunoglobulins (IgG 2660 mg/dL), and a decrease of C3 (44.2 mg/dL) and C4 (16.6 mg/dL). Histologic examination revealed the presence of typical MC lesions. In addition to an important acanthosis, it was possible to detect pyriform lobules of perfectly delineated epidermal cells, radially separated by fibrous septa that merge towards the central crater. The characteristic MC eosinophil bodies were observed in infected cells (Fig. 2). The lesions were treated with cryosurgery by spray. Many courses of therapy were given with intervals of 2-3 weeks. Every session consisted of two cycles of rapid freezing followed by a slow thaw. Many lesions disappeared with this treatment, and others were reduced in size, but total destruction of all lesions was not achieved (Fig. 3).

Strategy for identifying the gene encoding the DNA polymerase of molluscum contagiosum virus type 1

Molluscum contagiosum virus (MCV) is a member of the family Poxviridae and pathogenic to humans. MCV causes benign epidermal tumors mainly in children and young adults and is a common pathogen in immunecompromised individuals. The viral DNA polymerase is the essential enzyme involved in the replication of the genome of DNA viruses. The identification and characterization of the gene encoding the DNA polymerase of molluscum contagiosum virus type 1 (MCV-1) was carried out by PCR technology and nucleotide sequence analysis. Computer-aided analysis of known amino acid sequences of DNA polymerases from two members of the poxvirus family revealed a high amino acid sequence homology of about 49.7% as detected between the DNA polymerases of vaccinia virus (genus Orthopoxvirus) and fowlpoxvirus (genus Avipoxvirus). Specific oligonucleotide primers were designed and synthesized according to the distinct conserved regions of amino acid sequences of the DNA polymerases in which the codon usage of the MCV-1 genome was considered. Using this technology a 228 bp DNA fragment was amplified and used as hybridization probe for identifying the corresponding gene of the MCV-1 genome. It was found that the PCR product was able to hybridize to the BamHI MCV-1 DNA fragment G (9.2 kbp, 0.284 to 0.332 map units). The nucleotide sequence of this particular region of the MCV-1 genome (7267 bp) between map coordinates 0.284 and 0.315 was determined. The analysis of the DNA sequences revealed the presence of 22 open reading frames (ORFs-1 to -22). ORF-13 (3012 bp; nucleotide positions 6624 to 3612) codes for a putative protein of a predicted size of 115 kDa (1004 aa) which shows 40.1% identity and 35% similarity to the amino acid sequences of the DNA polymerases of vaccinia, variola, and fowlpoxvirus. In addition significant homologies (30% to 55%) were found between the amino acid sequences of the ORFs 3, -5, -9, and -14 and the amino acid sequences of the E6R, E8R, E10R, and a 7.3 kDa protein of vaccinia and variola virus, respectively. Comparative analysis of the genomic positions of the loci of the detected viral genes including the DNA polymerases of MCV-1, vaccinia, and variola virus revealed a similar gene organization and arrangement.

Sequence analysis of a Molluscum contagiosum virus DNA region which includes the gene encoding protein kinase 2 and other genes with unique organization

The nucleotide sequence of a near left-terminal region from the genome of Molluscum contagiosum virus subtype I (MCVI) was determined. This region was contained within three adjacent BamHI fragments, designated L (2.4 kilobases (kb)), M (1.8 kb), and N (1.6 kb). BamHI cleavage of MCVI DNA produced another 1.6-kb fragment (N'), which had been mapped 30-50 kb from the L,M region. The MCVI restriction fragments were cloned and end-sequenced. The N fragment that maps at the L,M region was identified by the polymerase chain reaction, using primers devised from the sequence of each fragment. The results from this analysis led to establish the relative position of these fragments within the MCVI genome. The analysis of 3.6 kb of DNA sequence revealed the presence of ten open reading frames (ORFs). Comparison of the amino acid sequence of these ORFs to the amino acid sequence of vaccinia virus (VAC) proteins revealed that two complete MCVI ORFs, termed N1L and L1L, showed high degree of homology with VAC F9 and F10 genes, respectively. The F10 gene encodes a 52-kDa serine/threonine protein kinase (protein kinase 2), an essential protein involved in virus morphogenesis. The MCVI homologue (L1L) encoded a putative polypeptide of 443 aa, with a calculated molecular mass of 53 kDa, and 60.5/30.2% sequence identity/similarity to VAC F10. The MCV N1L (213 aa, 24 kDa) showed 42.6/40.6% amino acid sequence identity/similarity to VAC F9, a gene of unknown function encoding a 24-kDa protein with a hydrophobic C-terminal domain, which was conserved in MCVI. The genomic arrangement of MCVI N1L and L1L was equivalent to that of the vaccinia and variola virus homologues. However, the ORFs contained within MCVI fragment M (leftward) showed no homology, neither similarity in genetic organization, to the genes encoded by the corresponding regions of vaccinia and variola viruses.

Analysis of molluscum contagiosum virus genomes isolated in Japan

The genomes of 477 Japanese strains of molluscum contagiosum virus (MCV) were analyzed using an in-gel digestion method with the restriction enzyme BamHI, and classified into four types, including a newly detected type (MCV type 4). All type 1 (MCV-1) genomes examined so far in Japan showed a common difference from the genome of the MCV-1 prototype (MCV-1p), the type reported to be most prevalent in Europe. The common markers of the variants of MCV-1 were 24-kbp fusion fragments generated by the loss of a BamHI site between the D2 and F fragments of MCV-1p. These variants of MCV-1 were classified into three groups (MCV-1va, MCV-1vb, MCV-1vc), with the variability among them being due to additions and losses of BamHI sites located in the right terminus and around the E and I fragments of MCV-1va. The restriction map of MCV-4 was generated and lined up with those of the other types. Cross-hybridization analysis revealed that the organization of all types of MCV genomes were essentially colinear. Considerable numbers of BamHI restriction sites were conserved between MCV-2 and 4, indicating a close analogy between them. The overall prevalence of MCV, as shown by the ratios of MCV-1 (MCV-1p):MCV-2:MCV-3:MCV-4, was 436(0):13:24:4. Thus, the molecular epidemiology of MCV in Japan is characterized by the absence of the European prototype of MCV-1, the exclusive occurrence and abundance of variants of MCV-1, a greater prevalence of MCV-3 over MCV-2, and the presence of MCV-4.

Enzyme-linked immunosorbent assay for measurement of IgG antibody to Molluscum contagiosum virus and investigation of the serological relationship of the molecular types

An ELISA was developed for measuring levels of IgG antibodies to Molluscum contagiosum virus (MCV) using DNA typed purified virus as antigen. The assay was found to be specific and sensitive for antibodies to MCV as well as being economical in its use of antigen. A close relationship was found between antibody levels to the MCV molecular types 1, 1v and 2 by cross-testing sera on plates coated with the different molecular types of the virus as antigen (P < 0.001).

Characterisation by restriction mapping of three subtypes of molluscum contagiosum virus

DNA from Molluscum contagiosum virus (MCV) isolates was analysed by restriction endonuclease digestion, identifying three virus subtypes. The structural features of MCV DNA are typical of poxviral DNA. Physical maps of cleavage sites for BamHI, CIaI, and HindIII were constructed for single isolates of each subtype. These differ extensively, indicating the independence of the three subtypes. However, they are closely related, as determined by molecular hybridisation and nucleotide sequence analysis, and their genomes are essentially colinear. There is marked geographical variation in the relative incidence of MCV I and II, whilst MCV III is uniformly rare.

Molecular epidemiological study of molluscum contagiosum virus in two urban areas of western Japan by the in-gel endonuclease digestion method

The in-gel endonuclease digestion method was introduced for the molecular epidemiology of molluscum contagiosum virus (MCV). We obtained clear electrophoretic patterns from 90.3% of single lesions. The distribution of MCV types in Western Japan was revealed to be different from that in other countries.

Direct detection of Molluscum contagiosum virus in clinical specimens by in situ hybridization using biotinylated probe

Molluscum contagiosum virus (MCV) is an unclassified poxvirus which has recently become recognized as causing a major sexually transmitted disease. At present no assay is available for specific detection of MCV because the virus cannot be serially propagated in cell culture. Since MCV produces an abortive, limited growth with some cytopathic effect in certain cell lines, we were able to develop an in situ hybridization assay for detection of MCV genome in clinical specimens. Human fetal diploid lung cell monolayers were infected with clinical specimens, and after proper incubation and fixation in paraformaldehyde, hybridization was performed under full stringency conditions with a molecularly cloned biotinylated probe. Only MCV infected cells showed homology to the MCV probe with a purple-brown cytoplasmic staining. Additionally, we have described an in situ hybridization assay for direct detection of MCV genome in formalin-fixed, paraffin-embedded biopsies. Characteristic intracytoplasmic Molluscum bodies (Henderson-Paterson bodies) were detected in stratum spinosum cells of the epidermis. Striking staining similarities have been observed between in situ hybridization and haematoxylin-eosin cytostaining. These procedures are the first successful identification of MCV genome in clinical samples by molecular hybridization, with sensitivity and specificity equal to or greater than electron microscopy.

Direct detection of molluscum contagiosum virus in clinical specimens by dot blot hybridization

A dot blot hybridization protocol was developed for the direct detection of molluscum contagiosum virus (MCV) DNA in clinical specimens submitted for virus isolation. Samples were concentrated by high-speed centrifugation and treated with proteinase K; this was followed by a single phenol-chloroform extraction step. The DNA was denatured, and the entire volume was spotted onto a nitrocellulose membrane. A biotinylated DNA probe specific for the BamHI-C region of MCV type 1 was used for hybridization. Evidence of MCV DNA was visualized by using streptavidin alkaline phosphatase conjugate and 5-bromo-4-chloro-3-indolyl phosphate-nitroblue tetrazolium as the substrate. Results showed that nonspecific hybridization does not occur with herpes simplex virus- or orf virus-infected clinical specimens and that dot blotting is more sensitive and reproducible than electron microscopy.

Sexually transmitted diseases: viruses and ectoparasites. Committee on Sexually Transmitted Diseases of the American Academy of Dermatology

This review highlights recent developments in the epidemiology, pathogenesis, diagnosis, and treatment of nonbacterial sexually transmitted infections. Genital herpes simplex, anogenital human papillomavirus disease, molluscum contagiosum, pediculosis pubis, and scabies are discussed.

Characterization of a molluscum contagiosum virus homolog of the vaccinia virus p37K major envelope antigen

We present the first nucleotide sequence data for molluscum contagiosum virus (MCV), an unclassified poxvirus. A 2,276-bp XhoI fragment from a near left-terminal fragment of MCV subtype I (MCVI) and a 1,920-bp XhoI fragment from the corresponding locus of MCV subtype II (MCVII) were sequenced and analyzed for open reading frames (ORFs). A large, complete ORF of 1,167 bp was present in both fragments. The putative polypeptide has a calculated molecular mass of 43 kDa (p43K protein) and was shown to have a high degree of homology to the vaccinia virus p37K major envelope antigen (40% amino acid identity and 22% conservative changes). The nucleotide content of the MCV fragments sequenced was 66% G or C. The codon usage within the gene for p43K reflected this high G + C content, with position 3 of codons being predominantly G or C (82 and 87% for MCVI and MCVII, respectively). The MCV p43K-encoding gene has motifs immediately upstream which are similar to those required for vaccinia virus late gene expression. The location and direction of transcription of the MCV p43K-encoding gene were equivalent to those of the vaccinia virus p37K gene, revealing similarity in genetic organization between MCV and vaccinia virus. Another, incomplete ORF was identified downstream of the p43K-encoding gene in both MCVI and MCVII. The sequence immediately upstream of this ORF overlapped the termination codon of the p43K-encoding gene and contained a motif which had homology to the derived consensus sequence for vaccinia virus early gene promoters.

Stability of molluscum contagiosum virus DNA among 184 patient isolates: evidence for variability of sequences in the terminal inverted repeats

The stability of the Molluscum contagiosum virus Type 1 genome (188 kbp) was studied in 184 DNA isolates from 131 patients. Variability of up to 1.5 kbp at both ends of the genome symmetrically was observed using restriction analysis of the DNA isolates and by Southern Blot experiments using cloned and labeled HindIII terminal DNA fragments of MCV-1 prototype DNA. The variable sequences were mainly confined to the terminal fragments and parts of the MCV-1 terminal repeats. Labeled probes did not detect terminal sequences of MCV Type 2 under the applied stringency. A less marked instability of the central MCV-1 BamHI DNA fragment F was observed within the genome coordinates 0.431 to 0.454 mu. Reiteration of tandem repeats similar to those described for vaccinia virus might explain the variability of the terminal sequences and might be involved in viral replication.

Molecular epidemiology of Australian isolates of molluscum contagiosum

Molluscum contagiosum lesions obtained from 75 Australian patients, 22 (29%) of whom were HIV positive, were examined by restriction endonuclease analysis and Southern blot hybridisation using radiolabelled and digoxigenin-labelled MCV DNA probes. The isolates were classified (MCV 1, 1v, 2, and 2v) on the basis of these results, which were in turn correlated with the clinical features of each lesion. A total of 44 (59%) of the lesions contained MCV 1 or 1v, 24 (32%) contained MCV 2 or 2v, three (4%) contained multiple MCV types, whereas four (5%) of lesions submitted contained no detectable MCV DNA. The ratio of MCV 1/1v to MCV 2/2v was determined to be approximately 1.75:1. There were substantial differences between the distribution of MCV types 1 and 2 among patients of different age groups, but no significant relationship between MCV type and the sex of the patient was found. MCV 2 was more frequently detected in lesions from anogenital areas and in immunosuppressed (HIV-positive) patients, and MCV 1 was more commonly isolated from skin rather than genital lesions, but neither association was statistically significant. Fragment F (10 kbp) obtained from the genome of MCV 1 was capable of differentiating MCV 1 from MCV 2 when used as a probe in hybridisation experiments with BamHI cut samples and may be useful when small amounts of lesion prevents differentiation by direct visualisation of restriction endonuclease fragments.

Molluscum contagiosum associated with AIDS: a case report with ultrastructural study

The clinical features of perioral molluscum contagiosum in a patient with the acquired immunodeficiency syndrome are described. Light microscopy and thin section electron microscopy revealed epidermal cells in different stages of degeneration showing two types of cytoplasmic inclusions. The basement membrane exhibited discontinuities and multiple laminations which may be a response to viral-induced cytotoxic effects.

Genomic characterization of Molluscum contagiosum virus type 1: identification of the repetitive DNA sequences in the viral genome

The genomes (188 kbp) of the prototype Molluscum contagiosum virus type 1 (MCV-1) and a variant strain (MCV-1v) were characterized by construction of the physical maps of the viral DNA for the restriction enzymes BamHI, ClaI, EcoRI, and HindIII using a defined gene library harboring the DNA sequences of the MCV-1 genome and by DNA-DNA hybridizations. It was found that the genomes of both MCV strains are identical, with the exception of very few changes in the DNA fragmentation patterns of restriction endonuclease BamHI as a consequence of naturally occurring nucleotide exchanges in the genome of the variant strain. Detailed hybridization experiments revealed the existence of repetitive DNA sequences, which are located within the terminal regions of the viral genome at the map coordinates 0 to 0.027 and 0.973 to 1.