A man who passed away in China's Yunnan Province tested positive for hantavirus, a rare type of virus transmitted from rodents to humans, and news reports about that event raised fears that a new disease outbreak was looming.
The reports came in late March 2020, as the world was reeling from the global COVID-19 pandemic caused by the spread of a novel coronavirus first detected in Wuhan, China, in the winter of 2019. Much of the hantavirus anxiety appears to have been sparked by a tweet from Global Times, an English-language publication based in China.
The tweet sparked viral memes and fears that, even as hundreds of thousands of COVID-19 cases are being reported worldwide and illnesses and deaths caused by the coronavirus continue to rise in the United States, a second disease outbreak was looming. Here is an example of a meme spreading on Twitter in late March (the user's name has been cropped out to protect privacy):
However, a single reported case of hantavirus in China does not an outbreak make, and hantaviruses are hardly new. They go back decades and aren't transmitted between humans like COVID-19. Instead, hantaviruses are spread from rodents to humans, and cases are extremely rare. The first strain of hantavirus was recorded during the Korean war, when it killed 190 American G.I.'s and sickened about 3,000.