A Comprehensive Report on the First Mpox Case in the Philippines: From Clinical Presentation to Shotgun Metagenomic Sequencing Analysis

Abstract

Abstract Background: With the World Health Organization’s declaration of the 2022 multi-country monkeypox outbreak as a Public Health Emergency of International Concern (PHEIC), we report the first confirmed case of monkeypox infection in a Filipino with clinical presentation different from the classic monkeypox cases previously reported in endemic countries of Central and West Africa before the 2022 outbreak. We describe monkeypox infection's gross and dermatopathological appearances on Southeast Asian brown skin. We also discuss the detailed process of monkeypox quantitative real-time polymerase chain reaction (qPCR) testing for diagnostic confirmation and the pioneering application of shotgun metagenomic sequencing to characterize the infecting virus. Case Presentation: This was a case of a 31-year-old male Filipino with a travel history to several European countries. He developed five non-tender, well-defined, umbilicated pustules with erythematous borders on the upper lip, the left gluteal area, bilateral knees, and the left ankle. Skin punch biopsy findings were suggestive of a viral infection. Monkeypox infection from Clade II (previously known as the West African clade) was confirmed by detecting and amplifying the G2R_G, G2R_WA, and C3L gene targets using qPCR. Shotgun metagenomic sequencing subsequently identified a monkeypox genome sequence belonging to B.1.3 lineage of Clade IIb, associated with the current multi-country outbreak. The serologic varicella IgM test was positive but varicella PCR of the skin lesion and metagenomic sequencing did not indicate the presence of the varicella virus. The patient was discharged and continued isolation at home until all scabs had completely fallen off. Conclusions: The presence of pustules among patients with risk factors such as possible close physical contact with infected individuals in areas with reported cases of monkeypox should raise suspicion for such an infection. Dermatopathological findings of the patient’s skin lesions were consistent with a viral infection but were non-specific for monkeypox infection. The establishment and optimization of the qPCR protocol were necessary to confirm monkeypox infection from Clade II. Metagenomic sequencing successfully characterized the etiologic agent of the first laboratory-confirmed monkeypox case in the Philippines belonging to Clade IIb which is mainly responsible for the 2022 monkeypox global outbreak.