LANZHOU, Dec. 26 (Xinhua) -- Contaminated factory exhaust was blamed for the 181 human cases of brucella infection in a veterinary research institute in Lanzhou, northwest China's Gansu Province, local authorities said Thursday.
The provincial health and agricultural authorities and the municipal government of Lanzhou said in a joint report that the infections were caused by the use of expired disinfectant at a nearby factory that produces animal brucellosis vaccines between July 24 and Aug. 20.
The failed disinfections resulted in the bacteria entering the exhaust emitted by the factory, which infected students and faculty members of the Lanzhou Veterinary Research Institute of the Chinese Academy of Agricultural Sciences, said the report.
As of Wednesday, a total of 181 people from the institute were confirmed antibody-positive. Only one of them showed symptoms, though.
Brucella, transmitted by contact with infected livestock including cattle and sheep or by eating unpasteurized dairy products, can cause brucellosis, also known as the Mediterranean fever. It is characterized by fever, malaise and headaches. The risk of human-to-human transmission is said to be minimal.
The report said the factory involved had suspended production pending investigation and overhaul.
Since December, 22 students and faculty members of Lanzhou University have tested positive for brucella antibody, among whom six had been to the institute. Another 13 cases in Heilongjiang Province also worked in the institute in August.