Epidemiological investigation and emergency response of the first confirmed case of mpox in Yunnan province, 2023

Objective To describe the illness course, epidemiological characteristics and response process of the first confirmed case of mpox in Yunnan province in 2023, and provide evidence for the prevention and control of mpox.

Methods An epidemiological investigation of the first case of mpox was conducted. Throat swabs, papular surface swabs, herpes fluid and other samples were collected from the case and close contacts for the detection of mpox virus by real-time fluorescence quantitative polymerase chain reaction and sequence analysis.

Results The case had high-risk behavior exposure outside Yunnan on June 16, 2023. On 22 June, the case showed genital itching with rash, fatigue, and muscle soreness. The case's throat swab, anal swab, urethral discharge and herpes fluid were all positive for the nucleic acid of mpox virus. The genetic sequencing results showed that the mpox virus isolated from the case belonged to the B.1.3 branch of the West African strain. In the 6 close contacts of the case, 1 was positive for nucleic acid of mpox virus, who once had homosexual intercourse. Six environmental samples, including case's bed sheets, duvet covers, and bathroom towels, were collected, in which one bedroom bed sheet was positive.

Conclusion Based on the comprehensive epidemiological investigation and laboratory results, the confirmed case of mpox was caused by domestic infection. It is necessary to monitor the trend of the mpox epidemic, strengthen health education. Meanwhile, the establishment of surveillance and early warning system should be strengthened for the better prevention and control of mpox.