The Investigation of the first confirmed Mpox clade Ib case in Chaiyaphum Province, Thailand — January 2025

Abstract

Background: On January 7, 2025, the Chaiyaphum Provincial Public Health Office identified one suspected case of Mpox. The patient had returned from Dubai, United Arab Emirates, and had a history of sexual contact with a man exhibiting symptoms similar to mpox. Consequently, a disease investigation was conducted to confirm the diagnosis, study the distribution of the disease by person, time, and place, identify risk factors, trace the source of infection, monitor close contacts, examine the Mpox surveillance system in Nong Bua Daeng Hospital and Chaieyaphum province, and propose appropriate disease control and prevention measures.

Methods: This descriptive epidemiological study involved a review of the patient's medical records, interviews with the patient, family members, physicians, and healthcare providers, and laboratory testing. Samples collected from the patient were analyzed for MPXV genetic material using Real-time PCR, and the virus strain was identified through DNA sequencing. Additionally, the Mpox surveillance and treatment system in Nong Bua Daeng District was evaluated.

Results: One confirmed case of the Mpox Clade Ib strain was identified. The patient was a 39-year-old Thai woman with no underlying medical conditions, working as a massage parlor employee. She had traveled from Dubai, UAE, and developed symptoms on December 24, 2024, including fever, headache, clear fluid-filled rashes in the genital area, swollen lymph nodes, and genital pain. Later, pustules appeared in the genital area and spread across the body. Genetic material of the Mpox virus was detected in the lesion swab, confirming the Clade Ib strain. Among 34 risk contacts monitored, no infections were found. This case was identified as an imported infection with no local transmission or outbreak in Chaiyaphum Province. The primary risk factor for infection was sexual contact with a man exhibiting Mpox-like symptoms. From the surveillance system assessment, it found that clinic staff were not aware of the reporting and referral channels when encountering a suspected Mpox case

Recommendations: Hospitals should review and update their disease and health threat surveillance systems to keep pace with current situations. Channels for coordinating and sharing information on suspected cases between private clinics and hospital epidemiology units should be enhanced. The surveillance of individuals returning from abroad, particularly those in high-risk occupations, should be strengthened. Additionally, public communication channels regarding risk awareness should be improved to reduce panic.