The number of confirmed cases of the highly contagious norovirus at the Pyeongchang Winter Olympics jumped by 42 to 128, organisers said on Thursday, on the eve of the Games. No athletes are among those taken ill with the stomach bug, which causes diarrhoea and vomiting, and organisers say they are doing everything they can to keep it that way. Any illness spreading to the competitors -- particularly one of the star names -- would be a major embarrassment to hosts South Korea. Hundreds of soldiers have been drafted in to guard Olympic venues after 1,200 security staff were withdrawn and quarantined earlier this week over the outbreak.