An intimate 10 second kiss can transfer over 80 million microorganisms including  bacteria and viruses . Although most of the microorganisms are harmless but some can transmit infection from one person to another causing certain diseases including -

  1. KISSING DISEASE also known as infectious mononucleosis  is caused by Epstein -bar virus and presents with flu like symptoms including fever ,sore throat , fatigue ,muscle weakness and swollen lymph nodes. The age group most affected  is 15-30 years of age . Symptoms can last for some days and the disease is self-limiting with no cure as such.
  2. GUM DISEASE namely gingivitis and periodontitis is normally a slow progressing , rather painless disease leading to bleeding from gums , loosening of teeth ,bad odour and if left untreated eventual tooth loss . The bacteria associated with gum disease have the potential to infect a healthy mouth if transmitted through saliva of the diseased person.
  3. MENINGITIS is inflammation of the protective lining of the brain and spinal cord and can have fatal consequences if not treated properly and promptly . Meningitis can be caused by both bacteria or virus though bacterial infections are less severe
  4. COLD AND FLU is the most common infection affecting the populations worldwide . As it is a droplet air borne infection deep kissing can always transmit the disease .
  5. HERPES SIMPLEX OR COLD SORES OR FEVER BLISTERS is perhaps the most common viral disease affecting the human race ,with the exception of the viral respiratory infections . Painful blisters form inside and around the mouth and rupture and bleed also .Herpes simplex virus from active lesions can be transmitted to a healthy mouth through exchange of saliva during kissing . Oral sex can also transfer the virus to the genital organs causing genital herpes infection . Further once a person is infected though the disease cures itself in most individuals in some days or weeks ,the virus always remains within the body and does get reactivated under certain conditions