Several people in China's northwest region have tested positive for bacterial disease in an outbreak which was caused by a leak at a biopharmaceutical company in 2019, said local authorities on Tuesday, September 15.

In Lanzhou, the capital city of Gansu province, the Health Commission confirmed that 3,245 local residents had contracted a disease called brucellosis—a highly contagious infection that spread from animals to people, mostly by unpasteurized dairy products.

A New Outbreak in China

As per the local health officials another 1,401 people have tested as preliminarily positive, but as of now no fatalities reported in the region. So far, the authorities have tested 21,847 people out of the city's 2.9 million population.

This disease can also cause symptoms including headaches, muscle pain, fever, and fatigue—some symptoms can become chronic and never go away, like swelling in certain organs, as per the US' Centers for Disease Control and Prevention (CDC).

brucellosis
Brucellosis infection European Centre for Disease Prevention and Control

CDC said that in this case, human-to-human transmission is extremely rare, but most of the people get infected by eating contaminated food or breathing in bacteria, which appears to be the case in the Chinese city. The outbreak started with a leak at the Zhongmu Lanzhou biological pharmaceutical factory.

The incident took place between late July to late August in 2019, said Lanzhou's Health Commission. While producing brucella vaccines for animals, the factory used expired disinfectants as well as sanitizers and that means not all bacteria were eradicated in the waste gas—it formed aerosols that contained the bacteria. The contaminated waste gas leaked into the air, and with the wind, it went to the Lanzhou Veterinary Research Institute, where the outbreak first hit.

As reported by Xinhua, people at the research facility began reporting infections in November last year, and it quickly accelerated. At the end of December 2019, when the Wuhan reported Coronavirus cases, at least 181 people at the institute had been infected with brucellosis in Lanzhou. Later, the outbreak spread to the Heilongjiang province.

In February 2020, the factory in question issued a public apology and said that it had "severely punished" eight people who were found to be responsible for the incident. On Tuesday, The Lanzhou Health Commission also announced that 11 public hospitals would provide free and regular checkups for infected patients.