Measles is the most contagious disease known to man. The measles virus is an RNA paramyxovirus of the Morbillivirus genus.  It is also known as rubeola.  There have been references to this virus as far back as the 7th century.  It is spread by respiratory droplets too small to be seen by the human eye.  Once these droplets are inhaled, the virus attaches to the lining of the airways and begins to multiply, which causes the disease. (4)

Measles is characterized by fever, coryza, coughs, and conjunctivitis.  In the developing world, this virus is the leading cause of infant mortality.  Measles (rubeola) has even been a significant health problem in the United States. In the period between 1989 and 1990, the incidence of measles increased sharply, reaching a peak in 1990 of over 27,000 cases. In 1992, after concerted national efforts to increase immunization, the incidence of measles had decreased to 2200 cases. Recent outbreaks have primarily affected two populations: nonvaccinated preschool-age children and previously vaccinated school-age children. Outbreaks affecting the latter are due to vaccine failure, waning immunity with age, and erroneous documentation of previous vaccination. Death, usually caused by pneumonia or encephalitis, occurs in 1-2 per 1000 reported cases.  (1)