The annals of military history are full of examples in which insect-borne
disease has played a crucial role in the outcome of a battle or a war:
In 1346, an army of Tartars besieged the city of Caffa on the Black
Sea. When an outbreak of plague developed among the Tartars, they hurled
their dead over the city walls until the citizens surrendered.
In 1803, weakened by malaria and yellow fever, a French invasion force
led by Napolean's brother-in-law failed to suppress a native revolt on
the French colony of Haiti. This military fiasco, which resulted in Haiti's
independence, probably discouraged Napoleon from establishing more footholds
in the New World and may have even hastened his decision to sell the Louisiana
Territory to the United States.
In 1814, Napoleon's military objectives were again thwarted by insect-borne
disease when an outbreak of typhus stalled his troops as they attempted
to invade Russia. Over the course of a three-year campaign, 105,000 of
Napolean's men were casualties of war and 219,000 were victims of insect-borne
During the Crimean War (1853-55), an invading Russian army was overcome
by hemorrhagic fever as it marched through the fly-infested swamps of southeastern
Europe. The allied forces of England, France, Turkey, and Sardinia easily
defeated the weakened Russians and retained their military control over
the region south of the Black Sea.
Yellow fever was a decisive factor in the Spanish-American War. By the
time the United States finally invaded Cuba in 1898, much of the Spanish
occupation force was already debilitated by disease and unfit to fight.
Typhus (trench fever) plagued troops on both sides during World War
I. The disease was probably responsible for prolonging the war because
neither side was healthy enough to wage a decisive battle.
Malaria played a major role in the fitness of armies on both sides of
the American Civil War (1861-1865). By the end of the war, 1.2 million
cases had been treated and 8,000 soldiers had died. Malaria was also a
factor on the Macedonian front during World War I, in the Phillipines during
World War II, and again in the Viet-Nam War where 80,000 cases were reported
between 1965 and 1971.