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Herpes virus. Illustration of a virus belonging to the Herpesvirus group. This group includes the viruses that cause chickenpox, shingles, glandular fever and cold sores. At the viral center (green) is the icosahedral (20-sided) protein shell of the virus, the capsid. This encloses the coiled nucleoprotein (genetic material). The capsid is surrounded by a lipoprotein membrane, the envelope (white). The envelope is acquired on release from host cells and is partly made from the host cell membrane. It is studded with peplomers (projections, blue) which form an irregular surface fringe surrounding the virus. Credit: Bo Veisland, MI&I / Photo Researchers, Inc.	AIDS virus. Colored transmission electron micrograph (TEM) of an AIDS virus (red/green) budding from the surface of a T-lymphocyte white blood cell. AIDS (acquired immune deficiency syndrome) is a fatal disease caused by HIV (human immunodeficiency virus). The virus particles attack T-lymphocytes, stealing their genetic machinery, thereby forcing them to produce more copies of the virus. The new virus particles then erupt from the cell to infect other T-lymphocytes. As these are a vital part of the immune system, the disease severely weakens immunity, making victims susceptible to seemingly harmless infections. Credit: Eye of Science / Photo Researchers, Inc.
Herpesvirus. Colored transmission electron micrograph (TEM) of a herpesvirus virus particle (virion). The herpesvirus group includes the viruses that cause chickenpox, shingles, herpes and cold sores. The protein coat of the virus, the capsid (red), encloses the genetic material (not seen). The capsid is surrounded by an irregular lipoprotein envelope (yellow). Herpesviruses cause vesicular eruptions, after which they may become dormant in the nervous system, often becoming reactivated at a later date. Magnification unknown. Credit: Dr. Linda Stannard, UCT / Photo Researchers, Inc.	Illustration of the AIDS virus (HIV) budding from the human T-cell cytoplasm. Credit: Chris Bjornberg / Photo Researchers, Inc.
Herpes simplex virus. Colored transmission electron micrograph (TEM) showing a cross section of a herpes simplex virus which belongs to the herpes virus group. It is a round virus with a diameter of about 150 nanometers. The core of the virus consists of double-stranded DNA surrounded by a protein coat, the nucleocapsid, (red at center) which has icosahedral symmetry. The nucleocapsid is surrounded by an envelope whose outer surface contains many small spikes. Herpes simplex causes common and troublesome infections characterized by the appearance of small, fluid-filled blisters. Magnification: x150,000 at 6x4.5cm size. Credit: A. Pasieka / Photo Researchers, Inc.	Color enhanced transmission electron micrograph of HIV Viruses infecting a T-4 lymphocyte. Human Immunodeficiency virus (HIV) is the causative agent of AIDS. HIV is spread through intimate contact with an infected person (sexual contact, shared intravenous needles). HIV invades the T-lymphocyte cells of the immune system, and reprograms the cells to produce HIV. AIDS develops as the bodies' immune system is destroyed and the number of T cells dwindles. Without T cells, AIDS patients have little defense against infection. 120,000x 70 mm. Credit: Chris Bjornberg / Photo Researchers, Inc.
Herpes simplex virus. Colored transmission electron micrograph (TEM) of a herpes simplex type I virus. The virus has an icosahedral capsid (protein coat, yellow) surrounding a core of DNA (deoxyribonucleic acid) genetic material. Herpes simplex type I is associated with oral cold sores. Herpes simplex is one of the most common viral parasites in humans. They cause small, fluid-filled blisters which may persist for weeks and, if touched, can spread the virus. Antiviral drugs may be helpful. Negatively stained. Magnification unknown. Credit: Dr. Linda Stannard, UCT / Photo Researchers, Inc.	Representation of the AIDS virus. Credit: James Cavallini / Photo Researchers, Inc.