There's hardly a contagious disease Abraham Verghese hasn't seen. Head of the Center for Medical Humanities and Ethics at the University of Texas Health Sciences Center in San Antonio, the infectious disease expert has authored My Own Country, about his work with AIDS patients, and The Tennis Partner.

Any summer "no-nos"?

I love to eat raw shellfish, but I can't think of anyone in infectious diseases who still does. So many places are polluted with sewage. Oysters are hazardous.

What about going abroad?

People can be casual about the effort involved. The combination of tremendous air pollution and high altitude in some cities can push you over the edge.

How do you eat overseas?

It's said travel expands the mind and loosens the bowels. Though I spent years in India, I eat moderately the first few days I'm there. I don't ever eat food that isn't fully cooked or that I can't peel, and I drink only bottled water. Nothing can ruin a trip like a bad gut.