If you ever wondered why a large number of your ancestors seemed to
disappear during a certain period in history, it may have been due to an epidemic. 

Epidemics have always had a great influence on people and therefore the genealogists 
trying to trace them. Many cases of people disappearing from records can be attributed 
to people dying during an epidemic or moving away from the affected area.

Some of the major epidemics in the United States are listed below

1657 -    Boston: Measles

1687 -    Boston: Measles

1690 -    New York: Yellow Fever

1713 -    Boston: Measles

1729 -    Boston: Measles

1732-33 - Worldwide: Influenza

1738 -    South Carolina: Smallpox

1739-40 - Boston: Measles

1747 -    Connecticut, New York, Pennsylvania & South Carolina: Measles

1759 -    North America (areas inhabited by white people): Measles

1761-61 - North America & West Indies: Influenza

1772 -    North America: Measles

1775 -    North America (especially hard in New England): Epidemic (unknown)

1775-76 - Worldwide: Influenza

1781-82 - Worldwide: Influenza (one of worst flu epidemics)

1788 -    Philadelphia & New York: Measles

1793 -    Vermont: Influenza and a "putrid fever"

1793 -    Virginia: Influenza (kills 500 people in 5 counties in 4 weeks)

1793 -    Philadelphia: Yellow fever (one of worst)

1783 -    Delaware (Dover): "extremely fatal" bilious disorder

1793 -    Pennsylvania (Harrisburg & Middletown): many unexplained deaths

1794 -    Philadelphia: Yellow fever

1796-97 - Philadelphia: Yellow Fever

1798 -    Philadelphia: Yellow Fever (one of worst)

1803 -    New York: Yellow Fever

1820-23 - Nationwide: "fever" (starts on Schuylkill River, PA & spreads

1831-32 - Nationwide: Asiatic Cholera (brought by English emigrants)

1832 -    New York & other major cities: Cholera

1837 -    Philadelphia: Typhus

1841 -    Nationwide: Yellow Fever (especially severe in South)

1847 -    New Orleans: Yellow Fever

1847-48 - Worldwide: Influenza

1848-49 - North America: Cholera

1850 -    Nationwide: Yellow Fever

1850-51 - North America: Influenza

1852 -    Nationwide: Yellow Fever (New Orleans: 8,000 die in summer)

1855 -    Nationwide (many parts): Yellow Fever

1857-59 - Worldwide: Influenza (one of disease's greatest epidemics)

1860-61 - Pennsylvania: Smallpox

1865-73 - Philadelphia, New York, Boston, New Orleans, Baltimore, Memphis, & Washington D.C.: a series of 
          recurring epidemics of Smallpox, Cholera, Typhus, Typhoid, Scarlet Fever & Yellow Fever

1873-75 - North America & Europe: Influenza

1878 -    New Orleans: Yellow Fever (last great epidemic of disease)

1885 -    Plymouth, PA: Typhoid

1886 -    Jacksonville, Fl: Yellow Fever

1918 -    Worldwide: Influenza (high point year) More people hospitalized
          in World War I more died from Influenza than wounds. US Army training camps
          became death camps --with 80 percent death rate in some camps

Finally, these specific instances of cholera were mentioned:

1833 -    Columbus, Ohio
1834 -    New York City
1849 -    New York
1851 -    Coles Co., Illinois
1851 -    The Great Plains
1851 -    Missouri

Other epidemics in the US - mostly in "big" east coast cities:

1813: "spotted fever" which we know as cerebral spinal meningitis--6,000 died.

1813 to ?: tuberculosis also called "consumption" was on the rise.

1842-43: erysipelas [strep infection of skin and mucous membranes