The call to Angela Rasmussen came out of the blue and posed a troubling question. Had she heard the rumour that key data sets would be removed from the U.S. Centers for Disease Control and Prevention’s website the next day?

It’s something Rasmussen had thought could never happen.

“It had never really been thought of before that CDC would actually start deleting some of these crucial public health data sets,” said the University of Saskatchewan virologist. “These data are really, really important for everybody’s health — not just in the U.S. but around the world.”

The following day, Jan. 31, Rasmussen started to see data disappear. She knew she needed to take action.

Rasmussen reached out to a bioinformatician friend, who knew how to preserve data and make backup copies of websites. With others, they scrambled to preserve the data in case it was deleted.

“We set about archiving the entire CDC website,” said Rasmussen.

Since then, Rasmussen and her colleague have teamed up with others like American health-care data analyst Charles Gaba and turned their attention to other sites with health data, preserving information from departments and agencies like the Food and Drug Administration (FDA) and the Centers for Medicare & Medicaid Services.

Rasmussen said the publication of some studies, such as three that would shed light on H5N1 bird flu, also appear to be affected by the change of administration.

Rasmussen is just one of several Canadian residents who have joined what has become an international guerilla archiving effort to preserve copies of U.S. government web pages and data being rapidly taken offline by U.S. President Donald Trump’s administration.