A Successful Cross-Agency Model for Collaborative Response to Imported Infectious Disease: Investigation and Management of the First Confirmed Clade Ia Mpox Case in Shanghai, China.

INTRODUCTION

Historically, human infections with clade Ia monkeypox virus (MPXV) primarily occurred through zoonotic transmission with limited secondary human-to-human transmission. Recent studies suggest increasing evidence of human-to-human transmission of some clade Ia lineages. This report documents the first imported clade Ia mpox case in Shanghai, representing the second documented case in China.

METHODS

Patient demographics, clinical profiles, epidemiological history, and close contacts were obtained through interviews with the patient and attending physicians. Clinical specimens were collected for real-time fluorescent quantitative polymerase chain reaction (qPCR) and whole-genome sequencing. Contact tracing was implemented, involving a 21-day health monitoring of close contacts.

RESULTS

The patient presented with moderate symptoms, including fever, rash, and respiratory manifestations. Genome sequencing identified the virus as clade Ia, showing 99.96% nucleotide identity to a strain from the Democratic Republic of Congo (DRC). Eight close contacts were identified with no secondary infection reported.

CONCLUSIONS

This case was confirmed as an imported clade Ia mpox case originating in the DRC. The "four JOINTs" cross-agency collaborative mechanism between the CDC and customs played a significant role in effectively stopping local transmission. Challenges in remote investigation highlight the need for stronger international collaboration. Establishing an integrated "early warning-control-tracking" system, coupled with public health intervention, is crucial for reducing importation risks and safeguarding national health security.