Aim 1&2/Clinical study: The primary outcome will be the safety of an escalating 30-week gluten challenge in hookworm naïve or hookworm infected people with CeD following a low or medium-dose hookworm infection, assessed by the change of duodenal villous height to crypt depth ratio (V:C) between pre-trial (week -2) and post-challenge (week 42). This will be a binary variable defined as safe if gluten challenge is completed and V:C ratio >2.0 and there is <20% change in its value from baseline or fail if drop out occurs prior to the completion of the gluten challenge or V:C ratio is <2.0 or its change from baseline is >20%.