Investigation and analysis of an outbreak of brucellosis in Guangdong rural areas in 2015

ObjectiveTo investigate a foodborne brucellosis outbreak in a county in Guangdong Province in 2015， which may provide suggestions for the prevention and control of similar incidents.

MethodsCase search was carried out by visiting cases， accessing the hospital medical record system， and collecting the registration information of rural health stations， and the results were described and analyzed.

ResultsA total of 169 cases were found， with an attack rate of 2.0‰ （169/85 000）. The onset time of the cases was from January 19 to June 2， 2015， showing a continuous and homogenous outbreak pattern. The clinical manifestations of the cases were fever （72%）， fatigue （40%）， hyperhidrosis （26%）， testicular enlargement （5.3%）， headache （2.4%）， and hepatomegaly （1.2%）. In addition， 54 cases of latent infection were found. A total of 13 strains of brucella ovis type 3 were cultured from the patients’ serum samples. After all sheep in the farm were sampled， 16 samples of serum test tube agglutination test were positive， with a positive rate of 37% （16/44）； after analysis， drinking fresh goat milk was a risk factor for brucellosis （OR=36.25， 95%CI： 4.68-280.73）， and there was a dose-response relationship between infection and milk drinking （χ²=27.00， P<0.05）.

ConclusionThe brucellosis outbreak was caused by patients who drank unboiled goat milk contaminated with Brucella ovine type 3. People are recommended to drink qualified and sterilized goat milk. Relevant government departments should strengthen the monitoring of goat selling and goat milk production.