Common DNA viruses are: (1) Hepadnaviruses, e.g. hepatitis B virus (HBV). It enters the body via hypodermic needles, blood transfusion, or sexual relations. (2)Herpesviridae: there are about 100 forms of herpes viruses, e.g. Herpes Simplex Virus Type 1 (HSV-1) causes encephalitis and enters the body thru lesions in the lip, skin, or eyes. HSV-2 is sexually transmitted and infects the genital and lip area which can lead to carcinomas. Varicella-Zoster virus (VZV) causes acute chicken pox and latent shingles. Cytomegalovirus (CMV) is dangerous if the immune system is compromised. It can be fatal to infants whose immune systems are not fully developed. (3) Papovaviridae: e.g. human papilloma virus (HPV) causes warts and tumors. (4) Poxviridae: e.g. smallpox. (5) Adenoviridae causes the common cold. Reference: Microbiology Demystified, by Dr Tom Betsy and Jim Keogh.