Molecular Epidemiological Study of a Human Brucellosis Outbreak - Weihai City, Shandong Province, China, 2022.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Brucellosis, mainly caused by Brucella melitensis (B. melitensis), is regarded as a significant zoonotic disease in China. In Weihai, located at the eastern end of the Shandong Peninsula, brucellosis has been in a low epidemic phase for the past five years.

WHAT IS ADDED BY THIS REPORT?: This was the initial report of a brucellosis outbreak in the last five years. Strains of B. melitensis bv. 3 from Weihai and other cities showed a close genetic relationship, suggesting a potential common ancestry.

WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Epidemiological investigations depend on standardized and effective molecular typing methods and analysis tools for public health laboratories to identify and trace outbreaks. Understanding the circulation patterns of livestock in free-range households in heavily affected areas is essential for controlling the spread of brucellosis.