India, June 11 -- The honeydew tasted like a sugary potato. That was my first clue that something was wrong.

I pride myself on having a keen sense of smell (sometimes to my disadvantage in putrid places), but overall it has served me well. So, you can imagine my dismay when, just days after returning from Thailand last year, I temporarily lost my sense of smell. As the American saying goes, the best part of coffee is waking up to smell it.

Anosmia was the single indicator that I might've caught an infection. I immediately bought a smell training kit online with vials of lemon, clove, eucalyptus, and rose, and whiffed them regularly, morning and night. Fortunately, my sense of smell returned to normal within weeks, and I soon forgot abou...