Quite accurate descriptions of scarlet fever have existed for over
three hundred years. One of the best of the early descriptions was
written by William Douglass, a doctor in Boston, at the time when the
first epidemic of this disease on this continent occurred in 1735-1736.
From the Atlantic Coast the disease gradually extended westward and
ever since has appeared at intervals in all parts of this country,
following the settlers into the new regions and often causing many
deaths among their children. A very striking peculiarity of scarlet
fever is the great variation in virulence at different times. Sometimes
it is so mild that scarcely any deaths are associated with it; at
other times it takes on such a high degree of virulence that it wipes
out whole families of children. In cities isolated cases are always
present, and at intervals of a few years epidemic outbreaks occur. For
many years in this country scarlet fever has gradually become less
severe and while the total cases of the disease have not been much
reduced, deaths have become much fewer. In recent years the proportion
of deaths in scarlet fever has varied from 1.5 to 10 per cent. The
death rate is highest in infancy and decreases with advancing age. Few
cases of scarlet fever occur in children under one year of age, the
largest number is observed in children up to 10 years. The disease is
not so infrequent in young adults, and occasional instances appear
in persons of quite advanced age. In these respects it resembles
diphtheria. The disease is most prevalent in late autumn and winter.