1495
Christopher Columbus and his troops fight the battle of Vega Real in Hispaniola. Many combatants contract a disease that remains unknown.

1643
An illness called the coup de barre (roughly translated as "temporary but extreme fatigue") strikes the Caribbean island Guadeloupe.

1647
An outbreak -- possibly yellow fever -- hits Bridgetown, Barbados, killing scores of people.

1648
The first presumed case of yellow fever is recorded in the Yucatan. Accounts of symptoms and how the disease spread are similar to those of later confirmed outbreaks.

1649
Between May and October, a third of the residents of Havana, Cuba, die from a disease believed to be yellow fever.

1665
A British squadron seizes St. Lucia. Most of the 1,500 troops assigned to the island succumb to yellow fever. Other European colonists of the Caribbean also fall victim to the disease.

1693
Boston becomes the first British colony in North America to face an epidemic of yellow fever. Charleston and Philadelphia soon experience the disease.

1702
New York City loses ten percent of its population to yellow fever.

1737
This summer begins seven consecutive years of yellow fever epidemics in eastern seaports. After 1743, the disease will not return to the region until 1762.

1793
Yellow fever kills an estimated 5,000 people in Philadelphia. Thousands more city residents will die in subsequent outbreaks over the next decade.

1822
Yellow fever is apparently eradicated north of the Mason-Dixon line. Historians credit this breakthrough to improved sanitary conditions. The disease continues, however, to ravage the South.

1833
December 3: Carlos Juan Finlay is born in Cuba.

1851
September 13: Walter Reed is born in Gloucester County, Virginia.

1853
New Orleans, the U.S. city in which yellow fever was most prevalent, suffers its worse exposure to date, with 8,100 official deaths.

1855
After two seamen die of yellow fever during the voyage, the steamship Ben Franklin arrives outside Norfolk, Virginia. The port doctor, unaware of the deaths, allows the ship to dock for repairs. Ten thousand residents fall ill from the disease; two thousand die.

1861-1865
During the Civil War, the Union establishes blockades of southern ports, which reduces trade with the Caribbean and South America. Possibly as a result, yellow fever kills only 436 of the 233,786 Union soldiers who die of disease during the conflict.

1867
Large-scale instances of yellow fever return to New Orleans, costing 3,000 lives.

1875
July: Army physician George Sternberg, who is later instrumental in establishing the Army's Yellow Fever Board in Cuba, publishes his first medical paper, "An Inquiry into the Modus Operandi of the Yellow Fever Poison," in the New Orleans Medical and Surgical Journal.

1878
After an earlier outbreak in New Orleans, more than half of Memphis' 47,000 residents flee when yellow fever reaches their city.

April 29: President Rutherford B. Hayes signs the Quarantine Act of 1878 into law. It gives the Marine Hospital Service responsibility for stopping disease from entering the country through shipping.

December 18: The Committee of the Senate and House of Representatives on Epidemic Disease establishes the Board of Experts Authorized by Congress to Investigate the Yellow Fever Epidemic. Six weeks later, the board recommends a quarantine system to prevent yellow fever from entering the country.

1879
March 3: Responding to calls for a federal public health agency, Congress establishes the National Board of Health.

1881
August 14: At Havana's Academy of Sciences, Carlos Finlay reads his paper, "The Mosquito Hypothetically Considered as the Transmitting Agent of Yellow Fever." His presentation was met with silence, a precursor to the doubts his theory faced for the next two decades.

1885
In Havana, 7,000 people die from yellow fever.

1898
February 13: An explosion destroys the USS Mainewhile anchored in Havana, killing 268 U.S. sailors and Marines. The incident leads to the Spanish-American War, which will expose U.S. troops to yellow fever.

1900
May 23: George Sternberg, surgeon general of the U.S. Army, recommends that a board be established for scientific study of infectious diseases, particularly yellow fever, in Cuba. Sternberg will choose Major Walter Reed, a physician in the U.S. Army, to lead the board known as the United States Army Yellow Fever Board.

May 24: Four doctors are named to serve on the board that will study yellow fever: Walter Reed, James Carroll, Aristides Agramonte and Jesse Lazear.

July: The board begins studying the disease, taking blood cultures from yellow fever victims before and after their deaths. Board members visit Carlos Finlay at his home in old Havana, hearing his theory that female mosquitoes transmit the disease.

August: The board begins testing Finlay's theory, allowing mosquitoes to feed on volunteers. For the first nine subjects, the results are negative.

August 27: Board member James Carroll, who hadn't believed that mosquitoes transmitted the disease, volunteers to be exposed to a mosquito that had fed on an active case of yellow fever twelve days before. Carroll contracts the disease. He becomes seriously ill but recovers.

September 25: Jesse Lazear, likely bitten by a mosquito used in his experiments, dies of yellow fever.

October 23: Walter Reed presents a "Preliminary Note" about the board's findings to the annual meeting of the American Public Health Association in Indianapolis.

November 20: Camp Lazear, named in tribute to the sacrifice of Jesse Lazear, is established. The Yellow Fever Board pays volunteers to expose themselves to mosquito bites in order to show that the insect transmits the disease. Fourteen volunteers contract the disease; all recover.

1901
February 16: Walter Reed publishes a paper on the board's work in the Journal of the American Medical Association. An accompanying editorial agrees that the results of the board's experiments prove the mosquito theory of transmission.

Following Army efforts to eliminate breeding grounds for mosquitoes in Havana, no cases of yellow fever appear in the city from September 1901 to July 1902.

1902
November 23: After his appendix ruptures, Walter Reed develops peritonitis and dies.

1904
April: Major William Crawford Gorgas, who served as sanitation chief in Cuba during the U.S. occupation, is assigned to the Panama Canal Zone. He works to control the mosquito population in order to protect workers on the canal project from contracting yellow fever.

1905
Yellow fever again strikes New Orleans, causing more than 900 deaths in the state of Louisiana. Mosquito mitigation efforts control the disease, marking the final epidemic in the United States.

1909
May 1: The Walter Reed Army General Hospital opens in Washington, D.C.

1929
Congress awards a special gold medal to surviving volunteers from Camp Lazear and members of the U.S. Army Yellow Fever Board or their next of kin.

1931
Yellow Fever: An Epidemiological and Historical Study of its Place of Origin, written by former Assistant Surgeon General Henry Rose Carter, is published after his death in 1925.

1936
November: A yellow fever vaccine, developed by researchers, including Max Theiler, at the Rockefeller Foundation Yellow Fever Laboratory in New York City, is first tested and put into production. As the threat of a world war appears, production is accelerated. The human serum in the vaccine causes an increased incidence of hepatitis.

1942
Max Theiler develops a safer serum-free vaccine for yellow fever which replaces the earlier vaccine.

1951
September: The Army medical complex in Washington, D.C. is renamed the Walter Reed Army Medical Center on the 100th anniversary of his birth.

October 13: Max Theiler is selected to receive a Nobel Prize in Physiology or Medicine. In his work at the Rockefeller Foundation, he developed a safe, standardized vaccine for yellow fever. He had also identified the virus that served as the basis of the French yellow fever vaccine and pioneered the use of laboratory mice to study the disease.

1966
November 21: President Dwight Eisenhower unveils a bronze bust of Walter Reed on the grounds of the Walter Reed Army Medical Center.

1996
The Walter Reed Society, established to preserve Reed's legacy, is founded.

2002
March: A Texas man, who had recently returned from a fishing trip in Brazil, dies from yellow fever, the third victim of the disease in the United States since 1996. Previously, no one in the United States had died from the disease for seven decades.

2003
January: The World Health Organization reports new cases of yellow fever in West Africa and the Sudan that caused at least sixty deaths.