Caused by virus:
1.Molluscum contagiosum. Caused by molluscum contagiosum virus (MCV). 
2.Acquired Immunodeficiency Syndrome. Caused by human immunodeficiency virus (HIV)
Caused by bacteria:
1.Gonorrhea. Caused by bacterium Nisseria Gonorrhoeae.
2.Syphilis. Caused by spirochaete bacterium called Treponema Pallidum.

Transmission of these diseases can be prevented by:
Bacterial by avoiding the use of clothes of infected person,by avoiding sexual intercourse,kissing or close body contact.
Viral by using condoms,by avoiding sharing of injection needles and by virtue of monogamy.

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