When, where and how the H5N1 bird flu virus may evolve and its capacity to spark a pandemic is hard to predict — in part, some researchers say, because of federal restrictions on gain-of-function research.

Public health officials have just reported the first known “severe” case of bird flu in the United States. There are now 61 confirmed cases across eight states. This week, the Centers for Disease Control and Prevention (CDC) announced that a person had been hospitalized with a “severe case” of bird flu.

The CDC has declared the first “severe” case of H5N1 bird flu in the U.S., according to a press release published Wednesday. The good news? The person who contracted the virus appears to have gotten it from backyard poultry,