An infant with congenital syphilis may be born without any symptoms, but will develop them within the first few weeks of life if not treated immediately. Early manifestations may include enlarged liver, enlarged spleen, swollen lymph glands, skin and mouth sores, inflammation of bones, and anemia. Individuals can be considered non-infectious after the resolution of open lesions with appropriate antibiotic therapy. Congenitally infected newborns can be rendered non-infectious once appropriate antibiotic therapy has been administered for at least 24 hours. It can be transmitted from pregnant women to the babies they are carrying.
Transmission can also occur through transfusion of unscreened blood or direct inoculation.