In the summer-fall of 1878 an epidemic of yellow fever destroyed the city of Memphis, Tennessee. Likely introduced into the Caribbean by trade from the West Coast of Africa and later brought up the Mississippi River by a steamer ship (the Emily B. Souder) with sick and dying sailors, yellow fever killed an estimated 5,000 Memphis residents, almost one-third of its population who did not flee the city that August . According to Molly Caldwell Crosby in her detailed account, the summer-fall 1878 yellow fever epidemic in the Mississippi Valley was possibly “the worst urban disaster in American history” .
Among the factors responsible for the 1878 tragedy were an unusually warm winter and spring that year, which helped Aedes aegypti mosquitoes to flourish in the Mississippi Valley, together with a lack of adequate urban drainage and a functioning sewer system, and a susceptible (non-immunized) population – the yellow fever vaccine would not be developed for another 50 years.
We need to seriously evaluate the risks of the major southern cities of the US, including Houston, but also New Orleans, Tampa, and Miami for their vulnerability to Aedes-transmitted arbovirus infections, such as yellow fever. As we have pointed out, cities such as Houston have emerged as important endemic zones for neglected tropical diseases. While we are aware that US urban areas may not be as vulnerable to yellow fever as Memphis was more than a century ago, there is still an important risk that needs to be considered as part of our national emergency preparedness, particularly in light of an emerging dengue problem (i.e., another Ae. Aegypti mosquito transmitted virus infection) in Houston and other southern coastal US areas.