[Investigation of human brucellosis cases in newly affected counties in Sichuan province, 2015-2017]

Objective: To understand the discovery of human brucellosis cases in new affected counties in Sichuan province, 2015-2017, and provide evidences for prevention and control of human brucellosis. Methods: The incidence data and outbreak data of human brucellosis in Sichuan were collected from Chinese Infectious Disease Surveillance Reporting System, and face to face interview, telephone interview and on-line survey were conducted to collect the case information, such as epidemiological characteristics, medical care seeking. Results: The incidence of human brucellosis in Sichuan has increased obviously since 2013, and 103 counties reported human brucellosis cases for the first time. A total of 23 cases of human brucellosis were investigated, and the common symptoms of the cases was fever, accounting for 91.30% (21/23). The cases mainly sought medical care in hospitals under county-level for the first time, accounting for 73.91% (17/23), and the misdiagnosis rate was 91.30% at the first diagnosis (21/23). The median interval between onset and diagnosis was 52 days, and the longest one was 142 days. Only 4.35% (1/23) cases knew human brucellosis, and when they contacted with suspected livestock, the use rate of protective clothing was 30.43% (7/23), the use rate of gloves was 8.70% (2/23), the use rate of mask was 4.35% (1/23), and the rate of washing hands with disinfectant after contact with livestock was 4.35% (1/23). Goat was suspected to be the infection source of all the cases, and 34.75% (8/23) of the cases were from Gansu, Qinghai and other provinces. The overall awareness rate of human brucellosis in the doctors was 34.58% (102/295), and the training rate was 58.31% (172/295). Only 33.33% (11/33) of the hospitals could perform laboratory diagnosis of human brucellosis and 34.78% (8/23) of county CDCs could carry out laboratory test of human brucellosis. Conclusions: The prevention and control of human brucellosis is facing challenge in Sichuan. The misdiagnosis rate was very high in newly affected counties, and the diagnosis were delayed obviously. The awareness of human brucellosis was low in the cases, and their awareness of self-protection was poor. The awareness rate about human brucellosis in doctors was low and they need more training; the capacity of brucellosis laboratory diagnosis in hospitals and CDCs at county-level should be improved.