Can laughter be infectious? A YouTube video featuring a Scottish grandmother reading The Wonky Donkey to her four-month-old grandson—in between irrepressible fits of giggles—seems to have had a contagious effect, sparking sales of the 2009 picture book from New Zealand, written by Craig Smith and illustrated by Katz Cowley.

Based on Smith’s song of the same name, the book features a cumulative rhyming text starring a three-legged donkey. As the story unfolds, the narrator introduces new details about the animal, concluding with the description of a “spunky, hanky-panky, cranky, stinky, dinky, lanky, honky-tonky, winky wonky donkey.”

The video, which was released on August 30 by Janice Clark (aka “The Scottish Granny”), has drawn close to half a million views. Smith told the Guardian in a recent interview, “The video is gold. Watching Janice read and laugh was just delightful, and like many, her infectious laugh had me laughing too. I’ve always wondered why sales had not taken off so much in the U.K. and U.S., but that looks like that’s about to change.”

Sales of The Wonky Donkey are indeed on the rise; the book currently sits at #1 on the Barnes & Noble bestsellers list, ahead of Bob Woodward’s Fear: Trump in the White House, and in second place on Amazon’s list.

Scholastic is responding to the surge in demand across all channels by bringing the book back into print. The Wonky Donkey will return to press in the U.S. with a print run of 50,000 copies (increased from the 20,000 copies initially planned). Scholastic first published The Wonky Donkey as an original paperback in 2010, with a modest print run, following its success with Scholastic Australia/New Zealand. To date, 75,000 copies are in print in the U.S.) The publisher expects the book to be back in stock in early October.