china Coronavirus

Residents wearing face masks and pyjamas are seen on a street in Shanghai, China, as the country is hit by an outbreak of the novel coronavirus, February 14, 2020.Reuters

As the world is still reeling under the Coronavirus pandemic, several thousand people in north-east China have tested positive for bacterial disease in an outbreak caused by a leak at a biopharmaceutical company last year. 

The Health Commission of Lanzhou, the capital city of Gansu province, announced that 3,245 people had contracted the disease brucellosis. The disease is often caused by contact with livestock carrying the bacteria brucella, CNN reported.

How did it originate? 

This outbreak began from a leak at the Zhongmu Lanzhou biological pharmaceutical factory, which occurred between late July to late August last year, according to the city's Health Commission.

Another 1,1401 people have also tested positive of the disease but there have been no fatalities 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.

What are the symptoms? 

The disease, also known as Malta fever or Mediterranean fever, can cause symptoms including headaches, muscle pain, fever and fatigue.

While some symptoms can become chronic or never go away, like arthritis or swelling in certain organs, according to the United States' Centers for Disease Control and Prevention (CDC).

Virus bacteria

REPRESENTATIONAL PICTURE: Researcher Clara Ocampo, PhD, Leader and Coordinator of Research in Biology and Vector Control of the International Training and Medical Research Center (CIDEIM) looks through a microscope eggs of Aedes Aegypti mosquitos on January 25, 2016, in Cali, Colombia.LUIS ROBAYO/AFP/Getty Images

Human-to-human transmission is extremely rare, according to the CDC. Instead, most people are infected by eating contaminated food or breathing in the bacteria -- which seems to be the case in Lanzhou.

While producing Brucella vaccines for animal use, the factory used expired disinfectants and sanitizers -- meaning not all bacteria were eradicated in the waste gas.

This contaminated waste gas formed aerosols that contained the bacteria -- and leaked into the air, carried by the wind down to the Lanzhou Veterinary Research Institute, where the outbreak first hit.

In the months after the outbreak, provincial and municipal officials launched an investigation into the leak at the factory, according to the Lanzhou Health Commission. By January, authorities had 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 cancelled in the factory.
In February, the factory issued a public apology and said it had "severely punished" eight people who were determined as responsible for the incident. It added.