Mpox virus genomic surveillance and typing in Sri Lanka, 2022-2025

Introduction: Mpox, a rare viral zoonotic disease attracted global attention in year 2022, with the global epidemic that occurred across non-endemic regions. This study aimed to determine the Mpox situation in Sri Lanka, with viral characterization, transmission dynamics and clinical profiles, within the context of the recent global epidemic.
Methods: This retrospective study utilized all samples of swabs from the lesions of suspected patients with mpox infection received by the National mpox laboratory, from May, 2022 to May, 2025. Commercially validated real time polymerase chain reaction was utilized to detect the mpox virus, followed by Oxford nanopore based whole genome sequencing for clade identification and phylogenetic analysis. Socio demographic and clinical characteristics were extracted from accompanied request forms.
Results: Five (11.36%) out of 44 samples tested detected the mpox virus. Four out of five positive samples were from patients aged between 15 to 45 years and male gender. One case was detected in a neonate. Four cases exhibited vescicular/pustular skin lesions and myalgia, while three and two cases experienced fever and lymphadenopathy respectively. Complicated disease with bronchopneumonia was present in the neonate. All cases reported a history of recent overseas travel. Genetic sequencing identified mpox clade IIb in all positive samples.
Conclusion: The study revealed all cases of mpox detected in Sri Lanka to be of clade IIb, on a par with the global outbreak which was primarily driven by the same. Chain transmission of Mpox infection was not observed within the country, with zero endogenous cases.