Detection of Molluscum contagiosum Virus (MCV) Subtype I as a Single Dominant Virus Subtype in Molluscum Lesions from a Turkish Population

A novel digital PCR assay for detection and comprehensive characterization of Molluscum contagiosum virus genotypes MOCV1, MOCV2, and MOCV3 and recombinant lineages

Molluscum contagiosum virus (MOCV) is an important human pathogen causing a high disease burden worldwide. It is the last exclusively human-infecting poxvirus still circulating in its natural reservoir-a valuable model of poxviral evolution. Unfortunately, MOCV remains neglected, and little is known about its evolutionary history and circulating genomic variants, especially in non-privileged countries. The design weaknesses of available MOCV detection/genotyping assays surfaced with recent accumulation of abundant sequence information: all existing MOCV assays fail at accurate genotyping and capturing sub-genotype level diversity. Because complete MOCV genome characterization is an expensive and labor-intensive task, it makes sense to prioritize samples for whole-genome sequencing by diversity triage screening. To meet this demand, we developed a novel assay for accurate MOCV detection and genotyping, and comprehensive sub-genotype qualification to the level of phylogenetic groups (PGs). The assay included a novel set of oligonucleotide primers and probes, and it was implemented using digital polymerase chain reaction (dPCR). It offers sensitive, specific, and accurate detection, genotyping (MOCV1-MOCV3), and PG qualification (PG1-6) of MOCV DNA from clinical samples. The novel dPCR assay is suitable for MOCV diversity triage screening and prioritization of samples for complete MOCV genome characterization.

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

Four molluscum contagiosum virus (MOCV) genotypes (MOCV1-4) and four subtype variants (MOCV1p, MOCV1va, MOCV1vb, and MOCV1vc) were partially characterized using restriction enzyme profiling in the early 1980s/1990s. However, complete genome sequences of only MOCV1 and MOCV2 are available. The evolutionary pathways of MOCV genotypes and subtype variants with unavailable sequences remain unclear, and also whether all MOCV genotypes/subtype variants can be reliably detected and appropriately categorized using available PCR-based protocols. We de novo fully characterized and functionally annotated 47 complete MOCV genomes, including two putative non-MOCV1/2 isolates, expanding the number of fully characterized MOCV genomes to 66. To ascertain the placement of any putative novel MOCV sequence into the restriction profiling typing scheme, we developed an original framework for extracting complete MOCV genome sequence-based restriction profiles and matching them with reference restriction profiles. We confirmed that two putative non-MOCV1/2 isolates represent the first complete genomes of MOCV3. Comprehensive phylogenomic, recombination, and restriction enzyme recognition site analysis of all 66 currently available MOCV genomes showed that they can be agglomerated into six phylogenetic subgroups (PG1-6), corresponding to the subtype variants from the pioneering studies. PG5 was a novel subtype variant of MOCV2, but no PGs corresponded to the subtype variants MOCV1vb or MOCV4. We showed that the phylogenetic subgroups may have diverged from the prototype MOCV genotype lineages following large-scale recombination events and hinted at partial sequence content of MOCV4 and direction of recombinant transfer in the events that spawned PG5 and the yet undetected subtype variant MOCV1vb.IMPORTANCEFour 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.

British Association for Sexual Health and HIV national guideline for the management of Genital Molluscum in adults (2021)

This guideline offers recommendations on diagnosis, treatment regimens and health promotion principles needed for the effective management of genital molluscum, including management of the initial presentation and recurrences. The Primary focus of the guideline is on infection which affects the genital area and has a sexual mode of transmission. This is an update to the guideline previously published in this journal in 2014.

2020 European guideline on the management of genital molluscum contagiosum

Molluscum contagiosum is a benign viral epidermal infection associated with high risk of transmission. The guideline is focused on the sexually transmitted molluscum contagiosum. The diagnosis is clinical with characteristic individual lesions, termed 'mollusca', seen as dome-shaped, smooth-surfaced, pearly, firm, skin-coloured, pink, yellow or white papules, 2 - 5 mm in diameter with central umbilication. Dermoscopy may facilitate diagnosis. Therapeutic options are numerous, including physical treatments (cautery, curettage and cryotherapy), topical chemical treatments (e.g. podophyllotoxin and imiquimod) or waiting for spontaneous resolution in immunocompetent patients. In pregnancy, it is safe to use physical procedures (e.g. cryotherapy). Immunosuppressed patients develop severe and recalcitrant molluscum lesions that may require treatment with cidofovir, imiquimod or interferon. Patients with molluscum contagiosum infection should be offered to be screened for other sexually transmitted infections.

Molluscum contagiosum in pediatric patients: to treat or not to treat? Could a personalized imiquimod regimen be the answer to the dilemma?

Background: Although molluscum contagiosum virus (MCV) infection is a common disease widespread among children and young adults, there is no shared opinion on treatment that can be divided into physical, chemical, medical (immunomodulating or anti-viral). According to some authors, MCV is best left to clear by itself.Objectives: To assess the clearance of MCV lesions in a sample of pediatric patients. It compares outcomes in treated with Imiquimod cream, compared with non-treated patients.Methods: The sample consits of 48 pediatric patients affected by MVC clinically diagnosed. It was divided into two groups: Group I, treated with Imiquimod 5% cream once/day until the onset of a visible inflammatory reaction. Once the reaction was illicited, application was suspended until the irritation resolved. If the lesion was still present, drug was administered again using the same regimen. The cycle was repeated until complete clinical resolution. Group II, control, comprises non-treated patients. Follow up visits were carried out 12, 16, 20, 48, and 52 weeks from the beginning of treatment.Results: At week 20, all patients except one in the treated group were lesion free. Persistence of MCV lesions was documented in one patient only until week 48. In the control group all patients were still affected by MCV lesions during the follow-up period. Spontaneous clinical resolution of the infection was observed in only 2 patients at week 52. The results of the study show Imiquimod's significant efficacy.Conclusions: Our study is one of the few case-control studies in pediatric population carried out with such long-term follow-up. Efficacy of this personalized treatment, scarce recurrence, absence of cicatricial sequelae and lack of necessity for deep sedation, in the case of children with disseminated lesions, makes the use of Imiquimod the first line of treatment compared with other destructive treatments or with no-treatment at all.

Molecular Screening and Single Nucleotide Polymorphism Typing of Molluscum Contagiosum Virus (MCV) from Genital Specimens, between 2012 and 2015

Background:

The present study is the first comprehensive report of the Molluscum contagiosum virus (MCV) in Iran based on the molecular technique for differentiation and typing of the MCV1 and MCV2.

Methods:

Patients were diagnosed as having tumor-like genital warts less than 5 mm in diameter, and HIV seronegative samples were chosen for this cross-sectional study. TaqMan real-time PCR was used to identify MCV following clinical examination. Typing of the MCV-positive specimens was performed in the SNP A27451G region of MC021L gene.

Results:

Of 1470 samples, 114 (7.75%) samples were positive for the MCV. From MCV-positive samples, 71.05% sequences were found to be related to the MCV1 and 28.95% to the MCV2.

Conclusion:

This assay constitutes a reliable method for identification and typing of the MCV genomic variants that could be valuable for reviewing the pathogenesis, molecular epidemiology, and the natural history of MCV-related situations.

Langerhans Cell Hyperplasia From Molluscum Contagiosum

Langerhans cell histiocytosis (LCH) carries a prognosis, which ranges from benign to potentially fatal. There is currently little framework to decipher metrics, which predict the benign versus aggressive nature of LCH. We wanted to determine whether molluscum contagiosum virus (MCV) DNA could be isolated from a cutaneous lesion, demonstrating Langerhans cell hyperplasia resembling LCH in a patient with both. Polymerase chain reaction on biopsy-proven MCV and the hyperplastic lesion has been performed. Two specific regions within the MCV genome were detected from both biopsies. The authors report our findings and suggest that some MCV can produce histological lesions resembling LCH, similar to the literature on scabies mimicking LCH. Efforts to find a reactive "driver" in LCH may significantly inform the clinical scenario.

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.

Overview of molecular biological methods for the detection of pathogens causing sexually transmitted infections

We review here different state-of-the-art molecular methods currently used in the diagnosis of sexually transmitted infections.