Richie Porte abandoned last year’s race as mechanical misfortune and a crash saw him tumble down the GC and later succumb to his injuries.
And on their latest Giro blow, Brailsford said: “Mikel was ill overnight but we spoke this morning and he started today’s stage with the hope of being able to pull through.
“It was pretty clear that the illness had badly affected him and that he wasn’t going to be able to continue.
“We are really disappointed for Mikel, who was riding well and looking forward to attacking in the mountains and animating the race.
“However we came here as a team and we’ll continue as a team. There is a long way still to go and, although our focus was on Mikel, there’s plenty of time for us to still make an impact at this Giro”
Team doctor Inigo Sarriegui confirmed Landa was suffering abdominal pains, likely to be caused by gastroenteritis, and will undergo further assessment in the team hotel in order to establish the best treatment.
Landa is the second Team Sky rider to leave the Giro d’Italia, after Elia Viviani was outside the time limit on stage eight.
Prior to stage ten, Nicolas Roche was Team Sky’s second-best placed rider, sitting 28th overall – 6’47” behind race leader Gianluca Brambilla.