I am reading “The Mississippi Valley’s Great Yellow Fever Epidemic of 1878” by Khaled J. Bloom, and as you can imagine I have yellow fever on the brain. The confusion that initially surrounded Yellow Jack—the name for yellow fever at the time—was deeply entrenched in the medical community. Some health officials believed that filth and dirty water were the causes of yellow fever. Others believed that there was something inherent in the atmosphere of cities that bred disease. And others believed that it had something to do with moist, warm air. All these theories were close to some type of truth, but they were muddled with panic and confusion. It makes sense that the people of Southern United States couldn’t wrap their minds around this disease because the virus nearly decimated certain states. In 1853 in New Orleans, Louisiana there were 40,000 cases with 11,000 deaths. Memphis was hit so bad that when the disease returned in 1879, the federal government was considering destroying the entire city of Memphis. The disease quickly became known as the King of Terrors. Although the scientific community didn’t know much about yellow fever it did loosely understand that yellow fever was a disease intertwined not only with people but also with the environment.
Mosquito vector-borne diseases are tough for several reasons. Firstly, the life cycles of mosquitos are complicated and include several stages with their own identities and properties. Secondly, the ecology and preferred environment of mosquitos play a big part in mosquito-vector diseases. Lastly, these guys can fly. Recently diseases such as yellow fever, dengue, and malaria have come up in the discussion of climate change (global warming!). As temperatures increases and climates shift, the range of habitat for insect vectors also shifts. Although there is merit to this idea, it seems to me like the histories of mosquito vector diseases have more to do with human activities and their effect on ecology than climate change do. Several articles also suggest human factors as a major driving point for the spread of the mosquito. Clearing forests, development into mosquito habitat, and everyday behavior play a large role in modifying the range of a mosquito.
When I mention the developed world, the specific area that I envision is Palo Alto, California. And surprise surprise the yellow fever mosquito has almost made its way here to Palo Alto, the land of bike lanes and bistros. In 2014 the San Mateo County Mosquito and Vector Control District found Aedes aegypti mosquitos at thirteen locations. The first location was in Menlo Park at the Holy Cross Cemetery. Furthermore this was the third mosquito in the Aedes genus that was found in Los Angeles, which isn’t too far away from Palo Alto. Although there was no disease associated with these mosquitos, I think the Ebola epidemic suggests how easy viruses can move in this day and age. Unlike Ebola where an infected individual would have to cross an ocean to reach the US, an individual infected with yellow fever would have to travel up from any country in Southern America to reach the US. No matter how improbable it seems like this would happen, it is possible, and that is what matters.