Several people from the Yanchangbao neighborhood around the Lanzhou Biopharmaceutical Plant told Caixin they started showing unexplained symptoms, including low fever and joint pain around September 2019.
Officials said at the briefing that as of Dec. 25, 181 of 671 blood samples tested positive for brucellosis antibodies among staff members and students at the Lanzhou Veterinary Research Institute in the neighborhood where the disease was first detected.
The government in late December arranged free blood tests and health consultations for residents in the Yanchangbao district, but no test results were made public.
Officials insisted that the contaminated exhaust contained low levels of bacteria and wouldn't damage people's health, even when tests detected antibodies.
A doctor told Gao in March that she had missed the best opportunity to treat brucellosis, and her disease developed into chronic brucellosis requiring long-term drug treatment.