Herpesvirus, any of the family (Herpesviridae) of common DNA-containing viruses, many of which are associated with human disease. See cytomegalovirus; Epstein-Barr virus; herpes simplex; herpe...

Antiviral drug, any of several drugs used to treat viral infections. The drugs act by interfering with a virus's ability to enter a host cell and replicate itself with the host cell's DNA. Som...

Deafness, partial or total lack of hearing. It may be present at birth (congenital) or may be acquired at any age thereafter. A person who cannot detect sound at an amplitude of 20 decibels in...

Sexually transmitted disease (STD) or venereal disease, term for infections acquired mainly through sexual contact. Five diseases were traditionally known as venereal diseases: gonorrhea, syph...

AIDS or acquired immunodeficiency syndrome, fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, a...