Several thousand people in northwest China have tested positive for a bacterial disease in an outbreak caused by a leak at a biopharmaceutical company last year, according to a CNN report.

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

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