|Delousing plant. 1918 U.S. Army Hospital, France, WW I|
Body lice occur wherever people live in overcrowded, unsanitary conditions with no or few opportunities to wash themselves or their clothing. Epidemics have occurred throughout history, especially in times of war, extreme poverty and cold weather where people huddle together indoors.
The nineteenth century saw devastating epidemics of typhus. More soldiers died of typhus during Napolean's wars than did of injuries sustained in battle (300,000 from typhus versus 100,000 from battle wounds). Typhus decimated the Irish population in waves in 1816, 1821, 1836 and 1846. The year 1846 was particularly bad. The Irish were starving as a result of the potato famine. Forced into workhouses, an estimated 190,000 people died of the disease. The twentiety century saw typhus in the Civil War and both World Wars.
It wasn't until 1910 that the transmission of typhus by body lice was proven. A vaccine was developed during World War II. Today, typhus still occurs, not so much in America, but in Eastern Europe, the Middle East and Africa.
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