Dozens of residents of Wuhan, the capital city of the Hubei province in China, haven hospitalized with an unidentified virus that is causing pneumonia-like symptoms. Chinese health officials have no idea how the virus is spreading or where it originated, but experts are tracking the progress of the outbreak in an attempt to halt its spread.

As the South China Morning Post reports, the sickness is being referred to as “unknown pneumonia,” though that doesn’t exactly offer much in the way of details. It seems that many of those who have been infected with the virus worked in the seafood industry and ran stalls at the Huanan seafood market, according to reports.

The illness has left at least seven people in serious condition, which needless to say is a bit scary. Thankfully, the unidentified virus has yet to claim a life. According to the Wuhan health department, at least a couple of hospitalized individuals saw their conditions improve enough to be discharged, pending a quarantine hold and further testing.

Based on what Chinese health officials have been able to figure out, none of the infections were the result of spread from one person to another. None of the doctors of hospital staff treating the patients has come down with a similar illness, and all of this suggests that the infected individuals came into contact with the virus at their place of work.

Officials are still working on getting to the bottom of the small-scale outbreak, though at the moment it would seem that they have a pretty good idea of where to look. Identifying the virus itself is a top priority, and tests are currently being run to narrow the list down, according to reports.