Pestilence in Philadelphia!

Let’s go to Philadelphia. It’s 1793: a busy marketplace bustles, full of the scent of West Indian stews and other temptations. Children run riot around boisterous chickens and ducks. The charcoal man sounds his horn to sell his wares. This is the world of Mattie Cook, a fourteen year old who helps run her family’s coffeehouse. The summer is hot, the mosquitoes are buzzing, and a new peril is about to enter Mattie’s life. I present to you ‘Fever 1793’, by Laurie Halse Anderson.



As we dive into Mattie’s world through the pages of her diary, we learn of the arrival of a dreaded new disease. Polly, the Cooks’ serving maid, falls ill suddenly and dies after a short fever. News soon begins to surface of more cases near the Philadelphia wharf, and the church bells begin their death toll. Soon, the bustling market becomes ghostly and abandoned as the Philadelphia inhabitants flee the city, barricade themselves up to wait for winter, or succumb to the grip of Yellow Fever.

The devastating effects of yellow fever are clearly described in Mattie’s diary, who contracts the disease herself along with family members and acquaintances. The symptoms of yellow fever are described fairly accurately: this tricky little flavivirus typically presents first with either an asymptomatic phase, or a ‘flu-like’ syndrome with fevers, chills, muscle and back aches, and nausea and vomiting. Although most people improve, a small proportion of about 15% will get better only to get worse again within hours, developing the toxic form of yellow fever. It is this serious form which is described vividly in ‘Fever 1793’, as liver failure causing the whites of the eyes to become yellow or jaundiced, and haemorrhage occurs causing vomiting of fresh or dark congealed blood. In fact, this is the story behind the Spanish name for the disease, vomito negro or ‘black vomit’.

At this time, bacteria and viruses were not known about, and so a variety of theories were expounded as to the cause of contagious diseases. Anderson hints at these through the conversations Mattie overhears in the coffeehouse. Mr Carris, a businessman, tells a captive audience that the “heap of rotting coffee beans on Ball’s wharf…it’s the source of a deadly miasma, a foul stench”; a government clerk interjects to suggest that the Santo Domingan refugees have come down with fever near the wharf. At the market, the German farmers Mr and Mrs Epler proclaim that the fever is a sign from God, to let sinners know they should have gone to church.

So what caused the yellow fever epidemic, and how did it spread so fast? Mr Carris’ miasma theory was a popular idea at the time. In fact until the mid 1800s, foul stenches from rotting matter were thought to be the root cause of epidemics: miasma translates as pollution from the ancient Greek. However, Anderson gives us readers clues as to the true reason for the spread of the disease, as Mattie swats away various irritating mosquitoes that have come out to swarm in the hot summer sun. These mosquitoes carry the yellow fever virus, inoculating it into humans and cause the spread of disease. The Aedes aegypti mosquito, pictured below, was and remains one of the main culprits for transmitting the yellow fever virus from human to human. During the summer months, these mosquitoes breed and multiply, but vanish with the winter frost, and as described in this book, so does the epidemic.

Aedes aegypti

Aedes aegypti mosquito biting human, author US Department of Agriculture. Image in public domain at:

Along with misconceptions about the true nature of yellow fever in the 1700s, the treatment options were limited, and often misguided. For example, Mattie’s mother Lucille contracts yellow fever, and is advised that “the pestilence boils within her blood and must be drained”. Ten ounces of blood are bled from Lucille, which with the gift of hindsight is likely to have caused far more harm than good as she has already vomited up a large amount of blood. In fact, the French doctors who have travelled to Philadelphia via the West Indies, with significant experience of yellow fever, hold this view. Later, Mattie is persuaded to avoid bleeding three small children in her charge who contract the fever, thereby most likely saving their lives.

Yellow fever persists today, although not in the United States. Travellers to certain places are required to have a yellow fever vaccine prior to entering certain areas in Africa and South America, for example. There are still no specific treatments apart from supportive therapies: rest, fluids, life-saving interventions in people who haemorrhage. But whereas the death toll during the 1793 Philadelphia epidemic was close to a staggering 10% of the population – 5000 of 50,000 died – the death rates nowadays tend to be much lower, with a total of 5100 deaths worldwide as reported in the Lancet Global Burden of Disease report from 2015.

‘Fever 1793’ by Laurie Halse Anderson does justice to a world yet to discover germ theory, at a time of limited understanding of public health interventions and specific medical therapy. Aimed at young adults, this book is definitely worth a read whatever age you are, to truly get to grips with this period of history.

Got a question or comment? Feeling blue about yellow fever?  Thinking of travelling somewhere exotic and making sure you’ve got your background research done? Get in contact with Infectious Reads below!


One thought on “Pestilence in Philadelphia!

  1. Pingback: The Microbe behind the Mask | Infectious Reads

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