A gas leak at a Chinese research lab has infected over 3,000 people with a bacterial disease that can cause lifelong illness.

Staff working at China Animal Husbandry Lanzhou Biopharmaceutical Factory, which used the bacteria that cause brucellosis in animals as part of a vaccine, had used out-of-date disinfectant for cleaning.

This error allowed exhaust gases from the vaccine creation process to become contaminated with aerosolised Brucella bacteria.

The gas escaped from the state-owned plant and was blown towards the nearby Lanzhou Veterinary Research Institute, where over 180 people were infected in December last year.

Cases have now cropped up in Heilongjiang province, several thousand miles from the initial outbreak.

The authorities have tested 21,847 people out of Lanzhou 2.9 million population

Brucellosis,is also known as Malta fever or Mediterranean fever. Mainly affecting livestock, its symptoms in humans include headache, fever, joint pain, loss of appetite and fatigue.

The infection is usually eradicated after a long course of antibiotics, but in some cases it can return throughout a victim’s life. Longer-term effects include inflammation of the heart and severe arthritis.

Health officials in Lanzhou said that 3,245 people tested positive for brucellosis after the gas leak. Preliminary tests from a further 1,401 people have also been marked as positive.

Human-to-human transmission of the brucellosis bug is extremely rare

Eleven public hospitals have been earmarked to provide the infected patients with free and regular checkup and compensation payments will start in October.

The precise amount of compensation has not been made public.

Factory managers issued an official apology in February and the facility has had its brucellosis vaccine production licence removed.

Eight people who have been found responsible for the gas leak have reportedly been “severely punished.”

People at the nearby Lanzhou Veterinary Research Institute reported the first infections in November, and it quickly accelerated

According to the NHS, Brucellosis is extremely rare in the UK but there have been some outbreaks across the globe in the past few decades. An outbreak in Bosnia infected about 1,000 people in 2008, making it necessary to cull infected livestock.

In the US, brucellosis is quite widespread, and endemic in wild bison, leading to billions of dollars of losses for the farming industry.

Human-to-human transmission is extremely rare, according to the US Centre for Disease Control. Most people who become infected pick the disease up by eating contaminated meat or drinking raw milk.