ABSTRACT
Objective To analyze the epidemiological characteristics of an outbreak caused by human brucellosis in a farm in Yantai City,to explore the causes and transmission routes,and to provide evidence for prevention and control of brucellosis in Yantai City.Methods In 2014,an on-site investigation was conducted in a farm where brucellosis occurred in Yantai City,and case searches were conducted on exposed populations in the farm.According to the investigation questionnaire on epidemiology of brucellosis in Shandong Province,general information,clinical manifestation and high-risk behavior exposure information of the cases were collected;blood samples were collected and tested by tiger red plate agglutination test (RBPT) and tube agglutination test (SAT).Brucellosis was diagnosed according to the "Diagnostic Criteria for Brucellosis" (WS 269-2007).Results The first case was male,58 years old,farm worker.A total of 38 suspected cases were found.Eleven patients with positive RBPT and SAT≥1:100 (++) were confirmed cases.The confirmed cases were all male,with a median age of 52 years,ranging from 40 to 60 years old;5 farm workers and 6 construction workers;the onset time was mainly in June and July,a total of 7 cases;clinical manifestations mainly included excessive sweating,muscle and joint pain,fatigue,testicular swelling,etc.Of the 147 sheep in the farm,47 were positive by laboratory tests,accounting for 31.97％,which were the main sources of infection.High-risk exposures for farm workers included hand-delivered births (5 cases) and breeding for livestock (1 case);high-risk exposures for construction workers included entry and exit of sheep houses (6 cases) and handling of supplies in sheep houses (6 cases).Conclusions The epidemic is caused by direct contact with Brucella-infected sheep or caused by respiratory contact with brucellosis contaminated environment.It is necessary to strengthen the health education for prevention and control of the disease in key populations and improve the awareness of the disease.