Nowadays yellow fever is considered a disease of urban tropical areas, but it in fact accounted for the largest number of individual epidemic outbreaks of any disease in the nineteenth century, and the outbreaks were no respecters of climate or environment. There were many of them throughout the colonial period up and down the United States, including in Texas.
Yellow Fever was known by various different names in different localities: Bronze John, Dock Fever (reflecting how it often spread from landing places), Stranger’s Fever and Yellowjacket. Not only did it cause thousands of deaths, but it also gave rise to large movements of people away from afflicted areas. Those who stayed where they were during epidemics would avoid other people by shutting themselves in their houses, away from all contact, including their work. The disease thus had a huge economic impact on the areas that it hit as businesses came to a halt. The death rate was in any case usually so high that people had to work both day and night to bury the dead.
The disease began with a headache, backache and muscle pains. Soon a fever developed, making the patient feel very sick, and by the third day there was a yellow colour to the skin, believed to be the origin of the name of the disease. Then there was bleeding in the eyes and mouth, and vomiting with blood. By the end of the first week, the patient was either dead or recovering.
It was observed that the disease was spread in the cargo of ships, or by infected people or their clothing, but it wasn’t discovered straight away that the cause was mosquito bites. This was a further refinement which was to be made by Walter Reed, an Army Medical Officer who had spent part of his career in remote frontier locations including in Arizona and Nebraska. In Havana in 1900, the US Army Yellow Fever Board on which he sat had a breakthrough: they concluded that mosquitoes were the transmitting agent for Yellow Fever. Reed was delighted that he had at last been able to do something to alleviate human suffering.
We know now that the female mosquito, once infected by biting an infected person or (more usually) other primate, is a carrier of the disease for life, having several thousand infective doses on board. At its most basic, control of the disease is through keeping numbers of mosquitoes to a minimum and by using mosquito netting. Vaccination against yellow fever is also routine for anyone visiting locations where there is the possibility of contracting the disease.