Rubella. Rubella (German measles) is a viral disease of numerous organs caused by an RNA virus and accompanied by a mild skin rash called an exanthem. First appearing on the body trunk, the rash spreads to other areas. Pregnant women may transmit the virus across the placenta to the developing embryo or fetus, and congenital rubella syndrome may develop in the newborn. Damage to the eyes, ears, and heart often result. Immunity can be rendered by an injection of attenuated rubella virus in the MMR vaccine.
Measles. Measles is also called rubeola. It is caused by an RNA virus normally transmitted by respiratory droplets during the coughing stage. Red spots with white centers occur on the cheeks, gums, and lips and are a diagnostic sign for the disease. These spots are called Koplik spots. The measles skin rash appears as a blush first on the forehead, then on the upper extremities, trunk, and lower extremities. Prevention is rendered by inoculation with attenuated measles viruses in the MMR vaccine. Complications of the disease may include measles encephalitis or subacute sclerosing panencephalitis (SSPE).
Chickenpox. Chickenpox is also called varicella. The disease is closely related to an adult disease called herpes zoster (shingles). The responsible virus is a DNA‐containing virus of the herpesvirus group. It is also known as the VZ virus.
Chickenpox is a highly contagious disease. Transmitted primarily by respiratory droplets, the disease is accompanied by teardropshaped lesions filled with fluid. The lesions begin on the scalp and trunk and then spread to the face and limbs. Prevention is possible with injections of inactivated VZ virus in the chickenpox vaccine.
Shingles occurs in adults and is believed to be a recurrence of infection by the virus that causes chickenpox. Presumably, the virus has remained latent in ganglia of the nervous system until it is reactivated. The disease is characterized by painful lesions surrounding the body trunk. The disease is highly contagious. Acyclovir may be recommended for therapy.
Smallpox. Smallpox is a viral disease caused by a large, boxlike, DNA‐containing virus having a complex shape. At one time, smallpox was a major cause of death in the world. It was accompanied by pus‐filled lesions covering the body surface, and usually it resulted in death. Immunity was rendered by an injection of cowpox (vaccinia) viruses, as first recommended by Edward Jenner in 1798. Smallpox has apparently been eradicated on the earth and has not appeared in humans since October 26, 1977. It is the first infectious disease ever to be eradicated.
Cowpox. Cowpox, also known as vaccinia, is caused by a DNA virus similar in shape to the smallpox virus. In barnyard animals, the virus causes a disease accompanied by lesions of the skin. These lessons also occur when humans are infected. Immunizations with cowpox viruses for smallpox protection are no longer given.
Molluscum contagiosum. Molluscum contagiosum is a skin disease caused by a DNA‐containing poxvirus. The disease is accompanied by flesh‐colored, painless lesions scattered over the skin surface. The disease is transmitted by skin contact.
Warts. Warts are considered an infectious disease caused by a number of papilloma viruses, which contain DNA. Warts vary in appearance, and are generally benign. However, certain types of warts can be forerunners of malignancies. Cases of genital warts are very widespread, and certain strains of virus are related to cervical cancers. Genital warts are transmitted by sexual skin contact. Other kinds of warts, such as dermal warts, occur in the epithelial cells of the skin tissues.