Syphilis in an Infant Acquired by Mouth-to-Mouth Transfer of Prechewed Food.

A 2-year-old infant boy presented with a large ulcerative lesion on his tongue. The grandmother who cared for the boy was in the habit of chewing food before giving it to the boy and had active syphilis. The infant was diagnosed with acquired early syphilis, which had been transmitted by prechewed food from his grandmother. Prechewing food is a custom in most parts of China. Prechewing an infant's food could be an avenue of disease transmission, although this is not fully recognized. No studies have been conducted to evaluate prechewed food as a disease transmission route.