STEM Tuesday — Spooky and Scary Science– Interview with Gail Jarrow

Welcome to STEM Tuesday: Author Interview, a repeating feature for the last Tuesday of every month. Go Science-Tech-Engineering-Math!

Happy Spooky Season! What better way to celebrate this deliciously horrific month than with a book that’s TERRIFYING?!

American Murderer: The Parasite That Haunted the South is a riveting tale of an unwelcome guest that wreaked havoc in the 19th and early 20th centuries by boring into unsuspecting bodies through the skin and leaving its human hosts with wrecked bodies and brains.

Horrifying! Let’s dig in with Gail Jarrow!


American Murderer

Included on NPR’s 2022 “Books We Love” List Finalist, 2023 YALSA Award for Excellence in Nonfiction ALSC Notable Children’s Book

Andi Diehn: My first question feels a tad obvious, but why did you devote a whole book to hookworms?!   

Gail Jarrow: Gross and disgusting appeals to many  in my audience of ages 10+. You can’t beat a vampire creature that clings to the inside of your intestine wall with its suction-cup mouth and sucks your blood until you get sick or  die. And what’s more disgusting than a discussion of leaky outhouses? But beyond that, my account of hookworm disease in the U.S. is a little-known story showing  the  changes in medicine and public health that occurred in the early 1900s. I also was drawn to the subject because it dramatically illustrates how  researchers used the scientific method to make medical discoveries.

AD: Arthur Looss and his accidental discovery of how hookworms entered the body – wow! What does this tell you about the courage of scientists (or at least that particular scientist!)? 

GJ: You have to admire them!  Looss made a dangerous lab error that he recognized as an opportunity. In  research for my books, I’ve encountered several scientists who have intentionally put themselves at risk. Sometimes they’re so sure of themselves that they don’t consider their experiment to be reckless. But in other less certain situations,  they decide that being a human guinea pig is the only way to test a hypothesis. In Bubonic Panic, I tell how Waldemar Haffkine injected himself with the first plague vaccine in 1897, keeping records of his physical reaction. In Red Madness, Joseph Goldberger swallowed a “pill” made of feces, urine, blood, and saliva from pellagra victims to prove that the disease wasn’t contagious. His 1916 experiment put the infectious theory to rest. (Pellagra is a vitamin deficiency disease.) In 1984, Barry Marshall successfully tested his hypothesis that a bacterium caused stomach ulcers by swallowing a beaker full of the microbe. He did get an ulcer, which he cured with antibiotics, but he also received the 2005 Nobel Prize in Physiology or Medicine for the discovery.hookworm

AD: Stiles’s name for his newly discovered hookworm – the American Murderer – is chilling! Why do you think he gave it such a chilling moniker?

GJ: Stiles wasn’t a subtle man. He knew this human hookworm killed people, and he gave it a name to communicate that fact. The name certainly brought attention to the parasite, and it gave me a good book title.

AD: Your descriptions of how people with hookworm were treated – even by medical professionals – is heartbreaking. What’s the lesson here? How can we use that moment in American history to improve current medical practices?hookworm victims

GJ: Having written a few books about the history of medicine, I’ve learned that  “accepted” theories can be wrong. Patients suffer when the mantra is “everyone agrees that. . ..”  As part of my research for American Murderer, I read medical books from the late 19th/early 20th centuries. According to the experts, human hookworm disease didn’t exist in the U.S. except in recent migrants. But Charles Stiles proved that was incorrect and that millions of southerners were infected, probably for generations. He had studied in Europe, where the disease was recognized and easily treated. The American medical establishment, particularly in the South, was slow to go along because Stiles was a parasitologist, not a physician. They also didn’t want to admit that, because of their ignorance, they’d misdiagnosed and failed to treat their patients for years. The sick people were dismissed by  their communities as lazy and stupid. And because victims were usually infected by hookworms at home,  it appeared as if these undesirable character traits simply ran in the family.  The lesson for today is that the medical community must be open to new ideas, knowledge, and approaches and should not dismiss them for the wrong reasons.hookworm education

AD: The cotton mills and Stiles’s narrow focus on hookworms – how might history have been different if Stiles had entertained the idea that other issues affected the mill workers?

GJ: Perhaps that  would have sped up reforms, especially concerning child labor. Still, just a few years later, in 1916, Joseph Goldberger and the U.S. Public Health Service investigated the health of mill workers and identified poor nutrition as a pervasive problem. These studies, as well as Lewis Hine’s photographs of child laborers, helped to bring reforms.

AD: The story of the hookworm is the story of public health – what did we learn from that era that we’ve put to use in more recent times, like with covid?

GJ: The hookworm campaign that started in 1909 demonstrated that in order to reduce or eliminate a disease,  it’s important to educate people about prevention and treatment. The information must be explained clearly and accurately without being condescending. In the early 1900s, newspapers were key to disseminating that information.The articles were written by Stiles, the Public Health Service, and doctors. Today we see similar efforts to transmit facts about COVID, influenza, prenatal care, vaccines, and other health concerns. But times have changed. People no longer have just one reliable source to keep them informed, such as their local newspaper. While additional kinds of media are available to educate the public today,  more unvetted, confusing, and false information is readily available, too.

before and after hookworm victim

A before and after image of a boy cured of hookworms

The hookworm campaign also showed that people are more likely to accept and act on information when they hear it from someone they trust. That meant keeping the  campaign local, at the county or state level and even in the schools and churches. The strategy was to reach people where they were, no matter who they were in terms of socio-economic status or race. The clinics  were staffed by local doctors and community volunteers known by the visitors. Today we see a decline in trust of public health institutions like the CDC and FDA–for many reasons. That’s proving to be a problem.

AD: It’s wonderful to see the before and after photos of victims who were cured, but I also worry about longterm effects on their mental/emotional health – did officials do anything to support individuals once they’d been cured of hookworm? 

GJ: Judging from the personal testimonies I read, I’d say that people who had been cured felt so much better physically that they were  happier and more positive about their lives. With energy to work and learn, they could support and care for their families. Rather than focusing on emotional support (an approach which is more of our time than theirs),  the campaign’s follow-up plan was to stop reinfection by educating hookworm victims about how the parasites spread and helping to install effective waste disposal systems at homes. State education departments added hookworm to the curriculum so that students learned about the disease’s cause, prevention, and treatment. Laws  in southern states required well-maintained outhouses in schools. Eventually, sewers were built in most towns and cities, which stopped the spread of hookworm and other intestinal diseases. But even today, many rural homes like mine are not hooked up to a municipal sewer, and it’s up to the homeowner to have a safe system. newspaper clippings

AD: Why was it important to you to bring readers to the present time to see what the worm situation is like today?

GJ: I always aim to convey hope in my endings.  Hookworm infections were significantly reduced in the United States. Research brought better treatments. The recognized importance of proper waste management spurred  infrastructure improvements.  At the same time, I tried to get young readers to think about what happens when they flush  a toilet and how their health can be affected by tiny parasites. I even included some advice about wearing proper footwear on our southeastern beaches to avoid infection by dog hookworms. 

I also wanted young readers to be aware that at least 1.5 billion people worldwide are still afflicted with soil-transmitted worms, including hookworms. These infections negatively impact a country’s economy and political stability.  It’s essential to know what’s going on in the world beyond. Sooner or later, these things affect all of us.


Gail Jarror headshot

Gail Jarrow is the author of nonfiction books and novels for ages 8-18.

Her books for young readers have earned the Winner of the Excellence in Nonfiction Award from YALSA-ALA; the Robert F. Sibert Honor Book Award; Orbis Pictus Honor; Children’s Book Guild Nonfiction Award; the Jefferson Cup; Grateful American Book Prize Honor; Golden Kite Honor for NF for Older Readers; Eureka! Gold Award; ALA Notable Book; Notable Social Studies Trade Book; the National Science Teaching Association Outstanding Science Trade Book and Best STEM Book, Best Books awards from Kirkus Reviews, School Library Journal, Booklist, Bulletin of the Center for Children’s Books, Bank Street College of Education, New York Public Library, Chicago Public Library, and NPR. She has received additional awards and recognition from the American Booksellers Association, American Library Association, Public Library Association, the Society of School Librarians International, and Junior Library Guild.


Andi DiehnAndi Diehn grew up near the ocean chatting with horseshoe crabs and now lives in the mountains surrounded by dogs, cats, lizards, chickens, ducks, moose, deer, and bobcats, some of which help themselves to whatever she manages to grow in the garden. You are most likely to find her reading a book, talking about books, writing a book, or discussing politics with her sons. She has 20 children’s books published or forthcoming.

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