Case Report

First identification of Molluscum contagiosum poxvirus from human in Senegal

Fatou K. Top, Landry G. Boussiengui, Ndèye C. Sall, Martin Faye

Received: 29 July 2025; Accepted: 13 Nov. 2025; Published: 08 May 2026

Copyright: © 2026. The Authors. Licensee: AOSIS.
This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license (https://creativecommons.org/licenses/by/4.0/).

Abstract

Herein, we report on the first identification of a human case of Molluscum contagiosum virus (MOCV) in Senegal. In 2024, a male child living in Diamniadio, Dakar region, with no history of travel, tested positive for MOCV. The aetiology was identified using metagenomic sequencing in the framework of the ongoing preparedness activities for the 2024 mpox public health emergency of international concern (PHEIC). Given the overlapping clinical features of MOCV infection and mpox, further research on MOCV is warranted in the West African region, particularly in the current context of high mpox circulation.

Keywords: Molluscum contagiosum virus; Senegal; human infection; mpox surveillance; metagenomic sequencing.

Molluscum contagiosum virus (MOCV) is a double-stranded deoxyribonucleic acid (DNA) poxvirus¹ that causes a common skin condition that predominantly affects children between 2 years old and 5 years old; however, the infection was also reported in sexually active adolescents and adults with normal immune systems and in immunocompromised individuals of all ages.² Molluscum contagiosum virus presents a large genetic diversity with four distinct subtypes (MOCV1–MOCV4), which differ in their genomic composition, geographic distribution and host associations. Among these, MOCV1 is the most prevalent globally, whereas MOCV2 has been increasingly detected in adults, immunocompromised individuals and sexually transmitted infections.³ Molluscum contagiosum virus infection typically follows a benign and self-limiting clinical course. After an incubation period of 2 weeks to 7 weeks, patients develop small, dome-shaped, umbilicated papules that are usually painless and may appear singly or in clusters on the face, trunk and extremities. Lesions often persist for 6 months to 12 months but may occasionally last up to 4 years, particularly in immunocompromised individuals. Secondary bacterial infection or inflammation may occur when lesions rupture or are scratched. In most cases, spontaneous resolution occurs without scarring as host immunity develops, although treatment may be indicated for cosmetic, discomfort or transmission concerns.^1,2 Although MOCV has not triggered large outbreaks, it represents a common cause of infectious disease worldwide and has been regularly isolated from humans since the eradication of smallpox.^4,5

On 21 August 2024, a 5-year-old male living in Diamniadio district, Dakar region, presented to Popenguine healthcare centre with fever, pain and vesicular mucocutaneous rash on the neck. The patient had no history of travel or contact with a known case with pox-like syndrome, and no other systemic symptoms were reported. Oral consent was obtained from the patient’s guardian. Blood and lesion swab samples were collected on the same day and sent to Institut Pasteur de Dakar (IPD) for diagnosis of mpox. The sample tested negative for mpox by quantitative polymerase chain reaction (qPCR) using a multiplex differential assay including mpox, measles, rubella and herpesviruses. The patient was treated with cantharidin, salicylic acid and tretinoin and was discharged on 22 August 2024. The sample was later subjected to a shotgun metagenomic sequencing method, enabling a comprehensive and quantitative assessment of the aetiologies present in a sample.

Interestingly, de novo assembly of generated reads showed a MOCV genome with 80% of coverage (GenBank accession number, MN931752.1). Phylogenetic analysis showed that the newly characterised sequence belonged to subtype 2 MOCV and was closely related to isolates from Slovenia and the United States between 2017 and 2023 (93%) (Figure 1).

FIGURE 1: Maximum likelihood phylogenetic tree of the newly characterised Molluscum contagiosum virus from Senegal in 2024.

Clinically, there is a challenge in differentiating mpox from infection caused by other poxviruses, such as MOCV, particularly when lesions are multiple or atypical. Our data exhibit the crucial need for differential diagnosis for skin infections during the current mpox outbreak. Although diagnostic resources are limited in many countries in Africa, investment in healthcare and laboratory infrastructures and resources could be prioritised by stakeholders. Continuous clinician training on the potential co-circulation of other skin infections during the current mpox PHEIC and integration of metagenomic sequencing as a second-line testing method in screening of mpox-suspected cases are essential for accurate identification of causative aetiologies. In addition, there is a need for development of specific and affordable assays for the detection of MOCV and promoting more studies integrating genomics and focusing on the assessment of prevalence and dynamics of MOCV in West Africa, especially the subtype MOCV2.

Our data are noteworthy by providing new insights into the epidemiology of poxviruses in West Africa where knowledge on poxviruses is limited. In addition, the newly characterised MOCV2 sequence could be useful in the development of specific diagnostics and therapeutics and in future longitudinal surveillance and experimental studies focusing on understanding MOCV2 molecular epidemiology, pathogenesis and possible transmission dynamics.

Acknowledgements

We thank the Ministry of Health and Social Actions in Senegal and colleagues at the virology and public health departments at the Institut Pasteur de Dakar (IPD) in Senegal.

The author reported that they received funding from Institut Pasteur de Dakar, which may be affected by the research reported in the enclosed publication. The author has disclosed those interests fully and has implemented an approved plan for managing any potential conflicts arising from their involvement. The terms of these funding arrangements have been reviewed and approved by the affiliated institute in accordance with its policy on objectivity in research.

Fatou K. Top: Formal analysis, Methodology, Writing – original draft, Writing – review & editing. Landry G. Boussiengui: Investigation, Methodology, Writing – review & editing. Ndèye C. Sall: Investigation, Methodology, Writing – review & editing. Martin Faye: Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Resources, Software, Supervision, Visualisation, Writing – original draft, Writing – review & editing. All authors reviewed the article, contributed to the discussion of results, approved the final version for submission and publication and take responsibility for the integrity of its findings.

This study was conducted in accordance with the guidelines established by the Senegalese MoHSA and was regularly supervised by the authorities of the Senegalese MoHSA. The protocol including a minimal risk, was approved by the Senegalese National Ethical Board Committee at the Senegalese MoHSA. Participant was enrolled after obtaining clear and appropriate informed consent and received no incentives for participation to this study. All methods, including the use of human samples, were carried out in accordance with the Declaration of Helsinki. The sample was anonymised.

This study received no external funding and was only supported by the IPD’s internal funds.

The authors confirm that the data supporting the findings of this study are available within the article.

The views and opinions expressed in this article are those of the authors and are the product of professional research. It does not necessarily reflect the official policy or position of any affiliated institution, funder, agency or that of the publisher. The authors are responsible for this article’s results, findings and content.

References