The Chinese government has taken down Plague Inc., the pandemic simulator/real-time strategy game for mobile devices, from app stores in the country, perhaps reflecting the tension and sensitivity there over a coronavirus outbreak entering its fourth month.

Officially, developer Ndemic Creations said in a statement Thursday that it was told by the Cyberspace Administration of China that the game “includes content that is illegal in China.” The takedown notice did not specify what that content was.

Reached by Polygon for additional comment, James Vaughan, Plague Inc.’s creator, said that “everything is quite unclear currently,” and that he would provide more information when he had it.

Daniel Ahmad, an analyst for Niko Partners who covers the video game industry in China and Asia, speculated that Plague Inc. was removed because of its recent Fake News update, in which disinformation now factors into the simulated spread of disease in the game. But Clement Renaudin, the former news editor of PocketGamer’s U.K. edition, pointed out that the Fake News update launched Dec. 4, more than a month before the outbreak was first identified by the World Health Organization. It has since declared a public health emergency of worldwide concern.

The Fake News update introduces a scenario in which players may create a disinformation story and then “deceive the world using modern tools and psychological tricks.” In its tutorial, the disease always starts in China. (In the main game, it may start anywhere.) A December announcement said that Ndemic had developed the scenario with Full Fact, a U.K.-based independent fact-checking organization, as well as the American group PolitiFact.

“The Fake News update in Plague Inc. will reach millions more people, helping them to understand the real threat that bad information poses,” Will McCoy, Full Fact’s chief executive, said at the time. Vaughan added that “it was scary how many of our infection algorithms translated perfectly to the world of false facts, fake news and bad information.”

Plague Inc., according to Ahmad, surged to No. 1 on China’s list of paid iOS games in January. In Thursday’s statement on China’s removal of the app, Ndemic Creations noted that the 8-year-old game has more than 130 million players and said it has been “the most popular paid game in China for many years.

“We have a huge amount of respect for our Chinese players and are devastated that they are no longer able to access and play Plague Inc.,” Ndemic wrote. “It’s not clear to us if this removal is linked to the ongoing coronavirus outbreak that China is facing. However, Plague Inc.’s educational importance has been repeatedly recognized by organizations like the [Centers for Disease Control] and we are currently working with major global health organizations to determine how we can best support their efforts to contain and control COVID-19,” which is the specific strain of coronavirus in this outbreak.

In a statement in mid-January, Ndemic noted the surge in interest in its game because of the coronavirus. “Whenever there is an outbreak of disease, we see an increase in players, as people seek to find out more about how diseases spread and to understand the complexities of viral outbreaks,” the studio said at the time. Plague Inc. launched in 2012.

“We specifically designed the game to be realistic and informative, while not sensationalizing serious real-world issues,” Ndemic said. “However, please remember that Plague Inc. is a game, not a scientific model and that the current coronavirus outbreak is a very real situation which is impacting a huge number of people.”

The coronavirus outbreak has dominated the international news for two months, roiled financial markets worldwide, and has threatened, or even postponed, sporting events ranging from Formula One’s Chinese Grand Prix to the 2020 Olympic Games in Tokyo.

In the United States, Sony canceled plans to travel to Boston for PAX East 2020 this weekend because of the virus’ spread. Sony, Oculus, Kojima Productions, and Square Enix’s Final Fantasy 14 development team also pulled out of attending the 2020 Game Developers Conference in San Francisco next month for the same concerns. And on Thursday, Epic Games announced it would not be attending GDC 2020, either.

In addition to China, where more than 75,000 people have fallen ill and almost 3,000 have died, COVID-19 has spread to almost 40 other countries, principally South Korea, Italy, and Iran. The Washington Post reported Wednesday that a woman in Northern California had contracted the virus, the first U.S. case not linked to travel to an affected region or contact with someone known to have the infection.

The United States has 59 other cases among people who either traveled to Asia or have had close contact with someone who has. Most of them, 42 of the 59, come from the quarantine of a cruise ship away from a Japanese port.