Epidemiological investigation of a brucellosis outbreak in a county in Guangdong

ObjectiveTo investigate and verify a food-borne outbreak of brucellosis caused by drinking raw goat milk in a county of Guangdong province, and provide suggestions for the prevention and control of similar outbreaks.

MethodsThe case finding was conducted through case investigation and hospital information system retrieval, the screening and confirmation of Brucella infection was conducted, and descriptive and analytical epidemiological methods were used to analysis.

ResultsA total of 30 cases and 6 latent infection cases were found. The cases occurred during 10^th July-18^th August in 2019 in this outbreak represented a homologous infection source. The main clinical manifestations of the cases were fever (70.00%), muscle and joint pain (46.67%), fatigue (43.33%), etc. A total of 21 Brucella strains were isolated from the blood samples of the people surveyed, all the strains were B.melitensis type 3. According to the analysis, the only definite risk factor was drinking raw goat milk from H's farm compared with drinking no H's milk ［RR＝16.91 (2.38−119.96)］ and compared with drinking boiled milk ［RR＝36.36 (5.07−260.58)］. Besides, the Brucella infection was related to goat milk drinking in a dose-response manner (χ²＝4.437, P＝0.035) and associated with drinking time.

ConclusionThis was an outbreak of brucellosis caused by drinking raw goat milk contaminated by B. melitensis type 3.