Thousands of people in China have contracted an infectious disease following a leak from a plant that makes animal vaccines.

Health officials in Lanzhou said 3,245 people tested positive for brucellosis, a bacterial disease often caused by close contact with infected animals or animal products.

Brucellosis, which is also known as Malta fever or Mediterranean fever, can cause symptoms including fever, headaches, muscle pain and fatigue.

According to the US Centers for Disease Control and Prevention (CDC), some signs and symptoms may persist for long periods of time while others may never go away or reoccur such as arthritis or swelling in certain organs.

A further 1,401 people tested as an early positive for the disease after the authorities screened nearly 22,000 residents in the city with a population of 2.9million, Mail Online reports.

Brucellosis is also known as Malta fever or Mediterranean fever

Officials said there have been no reported deaths or person-to-person transmissions and the CDC said it would be 'rare'.

Chinese authorities found China Animal Husbandry Lanzhou Biopharmaceutical Factory, a state-owned biopharmaceutical plant, had used expired disinfectant in its production of Brucella vaccines for animals between July and August last year.

This meant the bacteria was not eradicated in its factory exhaust so contaminated gas formed aerosols containing the germ around the factory.

The wind blew the gas to the Lanzhou Veterinary Research Institute where nearly 200 people were infected in December last year.

Thousands of people were tested for brucellosis

According to Xinhua news agency, more than 20 students and faculty members of Lanzhou University, some of whom had been to the institute, also tested positive.

The Lanzhou authorities said the factory - which apologised earlier this year - has had its brucellosis vaccine production licence removed.

On Friday Lanzhou's health commission said that sheep, cattle and pigs were most commonly involved in the spread of the bacteria.

Health chiefs have designated 11 public hospitals which will provide the infected patients with free and regular checkup and compensation payments will start next month.

Brucellosis is not unknown in China but it has declined since the 1980s due to improved vaccines and better disease prevention and control.

According to the NHS, it is extremely rare in the UK but there have been some outbreaks across the globe in the past few decades.

An outbreak in Bosnia in 2008 infected about 1,000 people and resulted in sheep and other infected livestock having to be culled.