Another 1,401 people have tested as preliminarily positive, the city’s Health Commission said. In total, authorities have tested 21,847 people out of the city’s 2.9 million population. No deaths have been reported.
According to the Centers for Disease Control and Prevention (CDC), the disease can cause symptoms including headaches, muscle pain, fever and fatigue. While these may subside, some symptoms can become chronic or never go away, like arthritis or swelling in certain organs.
State-run media reported the problem in December 2019, saying that “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.”
In a joint report, the provincial health and agricultural authorities and the municipal government of Lanzhou said 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 of 2019.
Apparently, expired disinfectants and sanitizers were used – meaning not all the bacteria were eradicated in the waste gas that was expelled through the factory’s exhaust system. (The report said the factory involved had suspended production pending investigation and overhaul).
Officials have since revoked vaccine production licenses for the plant, and withdrew product approval numbers for its two Brucellosis vaccines. A total of seven veterinary drug product approval numbers were also canceled in the factory.
In the US, brucellosis has cost the federal government and livestock industry billions of dollars. About 60 percent of female bison at Yellowstone National Park carry the bacteria, according to national park authorities.