It is a 
sexually transmitted bacterial infection, caused by the bacteria Treponema pallidum.
                                It is spread by direct contact with a syphilitic sore through skin and mucous membranes such
                                as lips, mouth, vagina, anus or rectum. Usually, this occurs during oral, anal, or vaginal
                                sexual activity. Rarely, syphilis can spread due to kissing too.
                                It can also spread from mother to baby during pregnancy which may lead to stillbirth or low
                                birth weight baby. And if it is left untreated, infant with syphilis can develop cataracts,
                                deafness, or seizures. In some cases, infants may die from the disease.