The illness caused the cancellation of Finland's training session on Wednesday afternoon at the Milano Rho Ice Hockey Arena, where they face champions Canada in their opening Group A game on Thursday.
Finland, who won bronze at the last two Olympics, will also meet the US, the Czech Republic and Switzerland in the preliminary round.
The Finns named Michelle Karvinen as captain on Wednesday. The 35-year-old forward plays for the Vancouver Goldeneyes in the Professional Women's Hockey League. Defenders Nelli Laitinen and Ronja Savolainen will serve as vice-captains.