"It is very unlikely, but possible. Some people, for example, are born with HIV, which they can pass to other people later in life when they start having sex. People can also pick up herpes through casual kissing — even from friends and family. Their herpes infections can then be passed on sexually. The chances of this happening are rare, so it’s not something to spend time worrying about. On the other hand, it’s another one of the many good reasons to always use condoms when you have sexual intercourse."
"No, the amount of virus transmitted through saliva in a kiss, is too little to infect someone else with HIV. BUT; if there are open sores in both mouths and blood is coming out, then there is a chance of HIV transmission."
"Yes. Syphilis is a sexually transmitted disease. A person with syphilis can spread the infection during the first two stages of the disease. If you come in contact with an open sore (first stage) or skin rash (second stage), you can pick up the bacteria that cause the infection. If the bacteria enter your body through an opening such as the penis, anus, vagina, mouth, or broken skin, you can get syphilis. If a person has had syphilis for more than two years, it's unlikely that he or she can spread the disease. Don't take a chance. Use a lubricated…"