Yellow fever was a constant blight for eastern American cities -- especially southeastern cities -- in the 18th and 19th centuries. Most outbreaks occurred in the summer months, but some summers would pass without incident. Severe outbreaks occurred mostly in the south, especially along the Gulf Coast.

But increased mobility in the period after the Civil War enabled the disease -- through infected carriers -- to travel farther inland. Health officials offered different theories about the nature of the disease and its transmission, but it wasn't until a Cuban doctor presented his observations on the transmission of the disease by mosquitoes to a board of American Army doctors that an understanding of the disease was mastered.

Yellow Fever hospital, Cuba

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