A blog post by the U.S. Centers for Disease Control and Prevention that mentions a "zombie apocalypse" as a lighthearted way to get Americans to read about preparing for hurricanes drove so much traffic that it crashed the website, the agency said on Thursday.
The CDC is a U.S. federal government health agency based in Atlanta.
"There are all kinds of emergencies out there that we can prepare for," the blog post begins. "Take a zombie apocalypse for example. ... You may laugh now, but when it happens you'll be happy you read this, and hey, maybe you'll even learn a thing or two about how to prepare for a real emergency."
The blog appeared just days before May 21, when an evangelical broadcaster in California has predicted "Judgment Day" will mark the end of the world.
"If you prepare for the zombie apocalypse, you'll be prepared for all hazards," CDC spokesman Dave Daigle told Reuters on Thursday.
The word zombie comes from voodoo practice of spirit possession in which victims are stripped of consciousness.
Zombies became popular culture references after the success of George Romero's 1968 horror film "Night of the Living Dead" where flesh-eating zombies roam the eastern seaboard in the aftermath of radioactive contamination.
Daigle said that a typical CDC blog post might get between 1,000 and 3,000 hits. The most traffic on record had been a post that saw around 10,000 visits.
By the end of Wednesday, with servers down, the page had 60,000. By Thursday, it was a trending topic on Twitter.
The campaign was designed to reach a young, media-savvy demographic that the CDC had not been able to capture previously, Daigle said.
Increased traffic did not affect the main CDC website.