A frightening new chapter was just added to the coronavirus saga, and it could dramatically complicate the fight against the outbreak. A new case study of one specific coronavirus patient reveals the virus’s extremely scary ability to spread even without producing symptoms in those it infects. That means an individual infected with the coronavirus could potentially spread the virus to people over the course of days or even weeks without even realizing he or she is infected with the virus in the first place.

The study, which was published in JAMA, focuses on a 20-year-old Chinese woman who was confirmed to have a coronavirus infection. It is believed that the virus spread from her to several of her family members, but what makes this case particularly interesting and potentially frightening is that the woman never developed any of the telltale symptoms.

The capability of a virus to spread without immediately producing symptoms makes it more difficult to detect and treat. Additionally, it could mean that the statistics and estimates regarding the number of infected individuals in China and abroad are wildly incorrect. That is, if the woman’s case isn’t an isolated anomaly.

The incubation period — the time it takes between when a person is infected with a virus and when they begin to show symptoms — can vary wildly depending on the person and the disease. We already know that the new coronavirus, COVID-19, is capable of hopping from person to person even during the incubation period.

The 20-year-old asymptomatic woman remained symptom-free and infectious for at least 19 days. Reports out of China suggest that the incubation period of the virus could stretch to nearly a month in some cases. Needless to say, this makes the already difficult task of containing the spread of the virus even more daunting, since people have likely been spreading it without even having the slightest idea that they were sick.

At this point, the total number of infected individuals is steadily approaching 100,000, worldwide, while the death toll sits at around 2,200. It has already infected far more people than SARS, and health officials around the world are waging a war against the spread of the disease as we speak.

Mike Wehner has reported on technology and video games for the past decade, covering breaking news and trends in VR, wearables, smartphones, and future tech. Most recently, Mike served as Tech Editor at The Daily Dot, and has been featured in USA Today, Time.com, and countless other web and print outlets. His love of reporting is second only to his gaming addiction.