Sexually transmitted diseases are infections that can be transmitted through sexual contact and passed from one person to another. Some of these diseases are: 

1. HIV/AIDS: People infected with the human immunodeficiency virus (HIV) have a weakened immune system and can eventually develop acquired immunodeficiency syndrome (AIDS). HIV can be transmitted through sexual contact, blood transfusions, shared needles or from mother to baby.
2. Hepatitis B and C: Hepatitis B and C viruses cause liver infections. These viruses can be passed through sexual contact, blood transfusions, contaminated needles or from mother to baby.
3. Genital Herpes Genital herpes is a viral infection caused by the herpes simplex virus. It is usually characterized by painful sores and lesions and is transmitted through sexual contact.
4. HPV (Human Papilloma Virus): HPV can cause genital warts and some types of cancer. It is transmitted through sexual contact.
5. Gonorrhea (Gonorrhea): Gonorrhea is a bacterial infection caused by the bacteria Neisseria gonorrhoeae. It can often cause urinary tract infections, vaginal discharge and, in certain cases, joint infections.

Regular screenings, use of contraception (e.g. condoms), sex education and reduction of risk factors are important to prevent these diseases. In addition, when symptoms of sexually transmitted diseases are recognized, a health professional should be consulted immediately and appropriate treatment should be sought.