The Health Commission of Lanzhou, the capital of Gansu province, confirmed that 3,245 people had contracted the disease brucellosis, often caused by exposure to livestock carrying the bacterium Brucella.
Another 1,401 people have tested positive in the foregoing, although no fatal reports have been reported, the city’s Health Commission said. In total, authorities have tested 21,847 people out of the city’s 2.9 million population.
According to the CDC, human-to-human transmission is extremely rare. Instead, most people are infected by eating contaminated food or breathing bacteria – which is the case in Lanzhou.
The outbreak stems from a leak at the Zhongmu Lanzhou biological medicine factory, which according to the city’s Health Commission takes place from late July to late August. When producing Brucella vaccines for animal use, disinfectants and sanitizers are used from time to time in the factory – meaning that not all bacteria were depleted in waste gas.
This contaminated waste gas formed aerosols that contained bacteria – and leaked into the air, reaching Lanzhou Veterinary Research Institute from the air, where the outbreak first struck.
Other infected patients included Lanzhou University students and faculty members; The outbreak also spread to Heilongjiang province, located at the most northeastern tip of the country, where 13 positive cases worked at the veterinary institute in August, Xinhua reported.
A total of seven veterinary product approval numbers were also canceled at the factory.
In February, the factory issued a public apology, saying it had “severely punished” eight people who were responsible for the incident. It said it would cooperate with local authorities in response and cleanup efforts, and would contribute to a compensation program for the affected people.
The Lanzhou Health Commission also announced in its report on Tuesday that 11 public hospitals would provide free and regular screening for infected patients. The report does not provide additional details on the compensation of patients, except that it will be launched in batches starting from October.