SAN FRANCISCO — With the threat of the coronavirus growing, Aleksandra Kuzmanovic sat at her computer in Geneva on Monday and sent out an important public health email. She works for the World Health Organization and her aim was to assess and stop a global spread — not of the dangerous virus but of hazardous false information.

She wanted to halt what her colleagues at the health agency are calling an “infodemic.”

She emailed a contact at Pinterest, the image-sharing social media giant based here in San Francisco, to ask if the site could help the W.H.O. combat the blazing spread of misinformation, lies and rumors about the new virus.

Offer accepted. Starting Thursday afternoon, when Pinterest users search for coronavirus, they get a link to a page of coronavirus “mythbusters” from the W.H.O.

Since the virus hit, Ms. Kuzmanovic said she and her colleagues have been in regular contact with the world’s biggest and most powerful disseminators of information — including Facebook, Twitter and Google, as well as social media influencers around the globe.