Dear Dr. Donohue: Recently my wife had her annual Pap smear. The doctor told her she has trichomoniasis, a sexually transmitted disease. Of course she asked me about this. I told her that the last time I was with another woman was more than 30 years ago. I am very certain that she has been faithful. Can you explain this to us? We are in our 60s. – B.T.

Dear B.T.: Trichomonas (TRICK-oh-MOAN-us) is a one-celled organism, like an amoeba. It is spread mostly through sex and is a common sexually transmitted infection. However, it can survive for several hours in a moist environment and can, therefore, potentially be spread in other ways. Being spread in nonsexual ways is rare.

Trichomonas can persist for a long time and not cause a single symptom, especially in men. A man can be a silent carrier, as can a woman.

Most females do have symptoms – a yellow-green, frothy and often malodorous vaginal discharge. The primary sign of male infection, when it occurs, is a penile discharge.

Your wife’s infection was discovered on a Pap smear. Pap smears frequently can be labeled mistakenly as being positive for trichomonas when there is no infection – a false positive. In this case, the Pap smear should not be used as definite proof of infection. Another test should be performed before declaring the woman infected. Two such tests are the RNA probe test and the nucleic acid amplification tests. There are others.

I don’t believe your wife ever had an infection. This situation pops up constantly and is a source of great domestic discord.

Dear Dr. Donohue: Nowadays there is such a to-do about gluten sensitivity and celiac disease. Which comes first? – F.G.

Dear F.G.: Gluten sensitivity and celiac disease are different names for the same condition. Gluten is a protein found in wheat, barley and rye. People with a sensitivity to gluten develop an inability to absorb nutrients, causing diarrhea and weight loss. Gluten acts like a poison to their digestive tracts. Treatment is avoidance of those grains and gluten.

Write to Paul Donohue, M.D. P.O. Box 536475, Orlando, FL 32853-6475.