Thousands of people in northwestern China have tested positive for brucellosis, a disease that commonly infects livestock, after a pharmaceutical factory accidentally vented bacteria into the air last year, officials say.
At least 3,245 people have contracted the disease in Lanzhou, the capital of Gansu province, according to a statement from the city’s health commission. More than 1,000 are suspected to have the disease. No fatalities have been reported since the problem was first identified last November.
The latest numbers are much higher than initially thought, the state-run Global Times reports.
Authorities have traced the leak back to the Zhongmu Lanzhou biological pharmaceutical factory, which was found to be using expired sanitizers and disinfectants. The factory accidentally vented an aerosolized version of Brucella, the bacteria that causes brucellosis, into the air last summer, causing it to spread across the surrounding area through the wind.
Brucellosis, also known as Malta, Mediterranean or undulant fever, is a bacterial disease typically found in cattle, pigs, goats, sheep and dogs, according to the World Health Organization. It’s also been found in humans, but it’s extremely rare to see human-to-human transmission.
The disease causes flu-like symptoms including fever, weakness, weight loss and malaise, the WHO says. It can also cause long-lasting issues such as arthritis and swelling in some organs, according to the U.S. Centers for Disease Control and Prevention (CDC).
The pharmaceutical factory was making brucellosis vaccines for animals when the leak happened in July and August of last year, the Lanzhou Health Commission says.
The first infections were reported at the Lanzhou Veterinary Research Institute in November and December, China’s state-run Xinhua News Agency reports.
Chinese authorities punished the pharmaceutical company by revoking permission for it to make various drugs.
Brucellosis can be treated with a multi-week course of antibiotics, according to the WHO.
The disease was fairly common in China until the 1980s, when vaccines and antibiotics helped the country rein it in. However, occasional outbreaks have been known to wreak havoc with livestock around the world.
Brucellosis has been effectively wiped out among livestock in Canada.