Aargh, no... We were so careful before we started the trek, because we know that Boliva and Peru are dirty countries, but we finally got food poisoning on the trail (we believe it was from water that wasn't properly boiled). Both of us more or less at the same time. It was quite bad, so for me it did not make sense to keep walking further, so I had to stop the trek and return to Lares. Petra noticed it a little bit later, so she had already started the day tour and therefore had to carry through (see next entry). The good thing is, she made it all the way up to 4600 and did really well. The bad thing is she had a hard time there.
For me, going back to Lares was a bit of an adventure. I was in no condition of moving, but I had to wait a few hours before I could return and then had to ride a horse for 3 hours. Man, this would have been OK with a healthy condition, but it was no fun in this case.
However, what really impressed me was the porter. While I was riding the horse, he walked next to it and carried all the luggage. I felt totally bad about this, and would have certainly packed differently if I had known he was gonna carry it all, but he seemed totally fine and was actually faster than the horse. There are rumors that 10 years ago he ran (!) the Inca trail within a time between 3 and 4 hours. Normally this is a 4-day tour, 45 km long, on roughly 4000 m height and with steep inclines. Completely crazy. They call him "Tiburon" (the shark). Well, that's a fitting name.