Hikers and joggers use garments made of merino wool in summer too because of the excellent insulating and regulating qualities:
http://shop.ibex.com/the-art-of-wool/why-merino-wool-in-the-summer
These garments are expensive!
On a different continent, the liner for a sleeping bag plus the woollen underwear would not have put him out of place as a pilgrim on the Camino de Santiago in Northern Spain.
And they can be worn for a longer period between washes, if need be.
http://www.outdoorgearlab.com/Travel-Underwear-Reviews
Travel clothing companies have addressed this issue by using special fabrics or anti-bacterial coatings. The keratin protein structure of merino wool is naturally resistant to bacteria. The wool of these soft sheep barely absorbs odors and clothing made from it, like the Smartwool and Icebreaker offerings, can last a long time between washes without getting stinky.
Thanks for the information. I rarely go hardcore hiking or sleeping in the outdoors anymore (damned dicky knees). Should we be looking closely at men from Europe, North America or NZ, who were travelling when they went missing? The police seem to have assumed he was a 'hippie' or Hare Krishna. Could he have been a backpacker? Also, contrary to popular belief, older people do stay in backpacker's/hostels; not just 20-somethings.