Context: Amid pandemic, thousands of people in northwest China tested positive for a bacterial disease called Brucellosis after a leak at a biopharmaceutical company in 2019. This was informed by authorities on September 15, 2020.  

• The Health Commission of Lanzhou, the capital of Gansu province, confirmed that 3,245 people have contracted the disease. The bacterial disease is generally caused by contact with livestock carrying the bacteria called Brucella. 
• Another 1,401 people have also tested as preliminarily positive. No fatalities have been reported as of now, as per the city's Health Commission. Overall, the authorities had tested about 21,847 people out of the city's 2.9 million population. 

What is Brucellosis disease? 

• The Brucellosis, also known as Mediterranean fever or Malta fever can result in symptoms such as fever, fatigue, headaches and muscle pain.  
• While some of the symptoms go away quickly, some of the chronic ones never go away like arthritis or swelling in certain organs, according to the US Center for Disease Control and Prevention (CDC) 

Can Brucellosis be transmitted from human-to-human? 

• The human-to-human transmission of the bacterial disease is extremely rare as per CDC.

How do people generally contract Brucellosis? 

• People generally contract Brucellosis by eating contaminated food or breathing in the bacteria.

What happened in Lanzhou? 

• In Lanzhou, as per researchers, the bacterial infection has been spread due to the leak in the biopharmaceutical company. People reportedly were infected by breathing in the bacteria.  

How did Brucellosis outbreak happen? 

• The Brucellosis outbreak in Lanzhou is being traced to a leak at the Zhongmu Lanzhou biological pharmaceutical factory, which occurred between late July and late August 2019. The factory used expired disinfectants and sanitizers while producing Brucella vaccines for animal use. This means that not all bacteria were eradicated in the waste gas. 
• The contaminated waste gas formed aerosols, which contained the bacteria and were leaked into the air, carried by the wind down to the Lanzhou Veterinary Research Institute, where the outbreak first hit.