His Passion Was Contagious

Even as a young man, George Craig loved learning about mosquitoes. Over his lifetime he became a world-renowned entomologist whose dedication to fighting disease inspired a generation of scientists.

Author: Deanna Csomo McCool

During his lunch hour, George Craig, Notre Dame’s Clark Professor of Biology, wasn’t about to dine all alone in his office, wasting time. If he was going to eat, so were his research subjects.

Surrounded by books, journals and newspapers, Craig, a bear of a man with a round, expressive face framed with dark-rimmed glasses, ate with his forearms resting on stout, cylindrical, paper boxes topped with mesh. Inside, mosquitoes fed on his arms while he ate his own lunch.


“That was pretty amazing to see, walking into his office and there he was, feeding all the mosquitoes,” says Ronald Hellenthal, biology professor emeritus. “That’s a testament to his dedication. I don’t know how many people would have done that.”

Even though his mother wanted him to become a doctor, Craig had fallen in love with entomology while working on his master’s degree at the University of Illinois, guided by a prominent entomologist there, William Horsfall, who fostered Craig’s interest in mosquitoes. After earning his doctorate from Illinois in 1956, Craig was recruited to Notre Dame the following year by Rev. Theodore Hesburgh, CSC, who was seeking to position the University as a powerhouse in the sciences.

At the time, the universities of Illinois, Wisconsin and Florida were the main academic centers for entomological research, according to Craig’s daughter, Sarah Craig Pratt ’98MSA. Colleagues told him, “You’re cutting off your career; there’s no entomology there.” But, she says, he liked the campus lakes and the University’s proximity to the woods and beaches along Lake Michigan. “He ignored their comments and said, well, he’d just go and build his own thing at Notre Dame.”

Craig was an entomologist and vector biologist whose interest in mosquitoes and the diseases they transmit to people was as contagious as the pathogens themselves. Hesburgh could not have chosen a more driven faculty member. In his 38 years at Notre Dame, before he died in 1995 at an Entomology Society of America conference in Las Vegas, Craig cultivated a legacy in a field that was in its infancy.

His personality attracted even more people dedicated to eliminating mosquito-borne diseases, and the circle widened in unexpected ways. The Chicago native directed more than 40 doctoral students and mentored 38 postdoctoral researchers. He created Notre Dame’s Vector Biology Laboratory — vectors pass diseases from one organism to another — with a focus on the Aedes genus of mosquitoes. He became Notre Dame’s first member of the prestigious National Academy of Sciences (NAS). And he developed a program that has turned out hundreds of new field biologists who have gone onto careers in academia and public health.

“Most vector biologists can trace their path back to Notre Dame,” says Nora Besansky, the Gillen Professor of Biological Sciences, who says that assessing the importance of vector biology at Notre Dame is “like saying, ‘Why is football important at Notre Dame?’”

Besansky, who this year was inducted into the NAS for her own study of the evolutionary, ecological and functional genomics of malaria vectors, adds, “All you have to do is travel around the world — Kenya, Tanzania, Australasia — and look at the people who are placed now in high governmental positions in vector biology and epidemiology, who have often gotten their Ph.D.s at Notre Dame.”

“George had an infectious enthusiasm for learning and teaching which piqued the curiosity of anyone who crossed his path to ask the question, ‘why?’” says Carol Hank Hoffmann, a member of the Board of Trustees whose mother, Joyce Hank, grew up with Craig. “Once in his presence you would discover an interest in mosquito-borne illnesses you never knew you had before.”

The English translation of Aedes — Craig’s preferred genus of mosquito — from Greek is “unpleasant.” The description is appropriate for the raised, itchy welt many people experience after being bitten by a mosquito, but that relatively minor reaction fails to represent the potential danger that mosquito-borne diseases can transmit to people.

Of the more than 3,000 varieties of mosquitoes in the world, about 200 to 300 bite humans; of these, only a few carry deadly diseases. Two, Aedes aegypti and Aedes albopictus, transmit a variety of viral pathogens that cause human diseases, including dengue, Zika and chikungunya. (Another genus, Anopheles mosquitoes, transmits malaria and other potential killers.)

Only female mosquitoes, which can live for up to a month, do the biting. They seek the nutrients from blood, such as proteins and iron, to produce the approximately 300 eggs they’ll lay in their lifetimes. During the brief period when they bite, they visit multiple hosts: monkeys, chipmunks, horses, birds and others, as well as humans. When a mosquito bites a victim that harbors a virus or parasite, that pathogen can be taken up by the mosquito’s body. Rather than be digested and excreted, the pathogen will replicate and travel to the insect’s salivary glands, infecting them.

One of Craig’s first accomplishments was finding morphological traits — genetically determined physical characteristics — in mosquitoes and mapping them.

When the mosquito dips her proboscis — her biting mouth part — into the next victim’s skin, she injects some of her saliva, which contains compounds that counteract blood clotting and inflammation as well as the pathogen that can infect the new host. The saliva, and not the transfer of blood — as with a syringe — is what transmits the disease to a new victim, which is why mosquitoes don’t transmit blood diseases like HIV or, in most cases, hepatitis, although recent research indicates that hepatitis C cells may grow inside mosquito cells, too.

Craig liked working with Aedes mosquitoes because they were relatively easy to rear, historically prominent and docile enough for the laboratory. He pioneered the study of mosquito genetics so they could be adapted and controlled independent of repellents or insecticides, which remain important tools that save millions of lives each year. Despite being deadly pests, mosquitoes are important to the ecosystem. They’re excellent pollinators and serve as important food sources.

However, if researchers can alter the genes and manipulate populations of mosquitoes, the insects might not be able to transmit disease at all.

One of Craig’s first accomplishments was finding morphological traits — genetically determined physical characteristics — in mosquitoes and mapping them. “Very basic tools,” says Besansky. “We’re doing the same thing now, at a molecular level.”

By 1962 Craig and his students had described nine inherited factors that can cause the bodies of mosquitoes to be modified, according to Craig’s 1998 NAS biography. By 1967, with colleague W.A. Hickey, he identified 87 mutants based on inbreeding for recessive alleles (alternative forms of a gene that arise by mutation). Linkage maps generated by his lab revealed 28 mutations on three chromosome pairs. He energized the field of vector biology through his work on Aedes ecology, population genetics, genetic mapping and the use of morphological mutants. The World Health Organization entrusted Craig and Notre Dame with its “library” of medically important Aedes mosquitoes from around the world.

He later abandoned his genetic-control methods for multiple reasons, including political ones — Besansky cites the example of propaganda that created fear that the genetically modified mosquitoes were “Trojan horses” designed to kill people in India where the work was being tested. But Craig and others were at the forefront of approaches being considered in the fight against mosquito-borne diseases today. One, a type of genetic-engineering technology called “gene drive,” uses molecular tools to replace a natural gene with a new gene — more advanced technology than what was available to Craig — to alter the chances that a specific gene will pass down to mosquitoes’ offspring, diminishing their ability to transmit a pathogen to humans.

“Many of us have spent our entire careers building on and advancing Craig’s research and vision; it is reflected in the wide range of genetic tools being developed, or in actual field testing today,” says entomologist David Severson, biology professor emeritus at Notre Dame.

George Brownlee Craig Jr. was born in Chicago on July 8, 1930, the only child of George Brownlee Craig and Alice Madelaine Craig, who were part of the early environmental movement and members of the Prairie Club of Chicago. Craig’s mother, who was the family’s primary breadwinner, had an iron will and a hard-driving work ethic and became an educator in the Chicago Public Schools. She held school for her son — after he came home from school.


Craig Sr., in and out of work during the Great Depression, built a cottage in Harbert, Michigan, where the family spent its summers. The younger Craig met his lifelong friend, Joyce Hank, through their parents’ involvement in the Prairie Club, and they enjoyed spending time at each other’s cottages on Lake Michigan in later years. Hank’s mother was the principal of the high school where Alice Craig taught.

“He was an absolutely fantastic reader, and long before even the term ‘speed reading’ had evolved, in a sense, he was doing that,” recalls Hank, who graduated from Saint Mary’s College in 1952. “He knew what he read, too. It wasn’t just eyes moving over letters, but he could literally ingest what he was reading. It was just fascinating.”

Craig went on to the University of Chicago Laboratory School, located in Hyde Park, where he graduated from high school in three years at age 16. In 1951, he completed an undergraduate zoology degree at Indiana University, then did his graduate work at Illinois. Military service took him to Maryland—a tour with the U.S. Army Preventive Medicine Detachment at Fort Meade and work as a research entomologist at what was then the U.S. Army Chemical Center — before he landed at Notre Dame.

By the mid-1970s, Craig held one of Notre Dame’s first endowed professorships and was on his way toward his NAS nomination and other awards, including the National Institutes of Health Merit Award for the productivity of his research. Continually financed through grants, his professional life was running smoothly and intensely. He left household management and child-rearing duties to his wife, Betty, but he had a special relationship with one of his children, Mary, who was his “mini-me,” Sarah Craig Pratt recalls. Like their father, Mary was highly intelligent and on the pre-medical track at Notre Dame as a freshman.

Sick, but with the cause elusive, Mary Craig was taken to the University of Michigan, where she was diagnosed with neuroblastoma. The devastating childhood cancer starts in the nerve cells of the sympathetic nervous system, which directs the stress-response circuitry often called the fight-or-flight response. Even though Betty Craig shuttled her daughter to Ann Arbor for treatments for two years, Mary died on February 4, 1978, while South Bend was digging out from one of the worst blizzards in U.S. history.

Betty Craig responded to the death of her daughter by talking about Mary to anyone who would listen; George Craig did not. Some colleagues didn’t know that Mary died of cancer; most said Craig worked even harder after her death. “He buried himself in his work,” says Pratt, who was 15 at the time, even though “he was already unbelievably driven.” Her father, she says, “could never mention her name again, ever.”

The loss made Craig even more compassionate with others who may have lost loved ones to disease, says Edward “Ned” Walker, now a professor at Michigan State University, who was a postdoctoral researcher for Craig in the 1980s. He could empathize with them because he had experienced such loss himself.

At Notre Dame, Craig snapped up the skills of promising students — even undergraduates — to assist with his studies. In the early 1990s, he was investigating the transmission of La Crosse Encephalitis, a disease caused by the virus passed by Aedes triseriatus — tree hole mosquitoes — through chipmunks. People who contract the disease, most common in the upper Midwest, might be free of symptoms, but children may develop seizures or even go into comas. About 1 percent of La Crosse Encephalitis cases are fatal.

As an undergrad, John Grieco ’90, now a medical entomologist and associate research professor at Notre Dame, would schlep daily at 5 a.m. — snowstorm or sunshine — from his Fisher Hall room to Galvin Life Science Center to watch chipmunks in cages react to mosquitoes. “Dr. Craig wanted us to be there every day,” says Grieco. “He said that living organisms don’t take a day off, so you can’t take a day off, either. Nature doesn’t follow your same patterns, just because you went to a party the night before.”

Previous research had indicated that chipmunks don’t react to mosquitoes. However, chipmunks respond to human movement by freezing in place, which created observer bias in previously published research. Researchers in Craig’s lab built a remote-controlled chamber in a room so they could discreetly watch the chipmunks.

Of course the chipmunks reacted. And more than once, the students documented chipmunks eating the mosquitoes. “That was the first time anyone had documented that behavior,” says Grieco, who with his wife, Nicole Achee, a research professor at Notre Dame, landed a $33.7 million research award in 2019 to study spatial repellents to ward off mosquitoes. “The primary route for La Crosse would be through a bite,” he explains, but this discovery opened up another possible route: ingestion.

He also inspired students to change their own paths, and led them to some of the highest positions in their fields.

Craig was literally also the first in the country to signal the alarm that an Asian species of mosquito, Aedes albopictus, a black mosquito with a striped body and legs, had entered the country at the Port of Houston in a shipment of used tires. Research determined the mosquito was cold-hardy enough to spread to the Midwest.

Craig’s students, including John Gimnig ’91, now a research entomologist with the Division of Parasitic Diseases at the Centers for Disease Control and Prevention in Atlanta, helped manage the colonies of these mosquitoes, which like to breed in  wet habitats like rock pools and the tires. Craig appeared on the national news to make the appeal that the threat was grave. He even gave the insect a new moniker, the Asian Tiger Mosquito. “He wanted to scare people with that name; to put fear in peoples’ minds,” Pratt says.

Craig’s obituary in The New York Times would say he felt the federal government ignored his warnings about the Asian Tiger Mosquito. “Their position is to wait for an epidemic, then do something about it,” Craig reportedly said. “That’s like jumping out of the Empire State Building and saying you’re all right 99 percent of the way down.”

As usual, Craig wasn’t wrong. The species also transmits Zika as well as Eastern Equine Encephalitis (EEE), which has taken the lives of a dozen people and numerous horses, 90 percent of which die if infected.

In the 1980s Craig had become interested in EEE and its spread, advocating for better tracking. States provided little or no payment for farmers to have their deceased horses tested, and testing could be traumatic — it involved removing a horse’s head. But Craig felt so strongly about the issue that in 1995, a month before his death, he paid the $76 diagnostic fee for a horse that proved to be infected with EEE, then wrote a scathing letter to the State of Michigan, blaming officials for failing to take the disease seriously.

George Craig rarely shied away from disagreements, but his former colleagues and students recognize that his strong will was, in fact, a leading reason he and Notre Dame became so well known for vector biology. “If he thought you weren’t interested in insects, that wasn’t good,” James Elser ’81, now a member of the National Academy of the Sciences, says with a chuckle. “Then he might not have so much time for you. If you were interested in insects, then it was great.”

Craig could have a temper, leading to professional disagreements and a healthy fear of his wrath, Ned Walker recalls. “But he had a tender heart, and I got along with him, even when I sometimes didn’t meet his standards or expectations,” he says. “But his drive was one of his strongest qualities, and he had very good work habits that made other people work even harder.”

He also inspired students to change their own paths, and led them to some of the highest positions in their fields. Dr. Thomas Quinn ’69, ’71M.S. attended Notre Dame planning to become a practicing physician, but a parasitology class with Craig pointed him toward medical research. “He’d take charge of the class like no other professor I’ve ever experienced.”

Quinn became founder and director of the Johns Hopkins University Center for Global Health and the chief of the International HIV/STD Section of the National Institutes of Health. He was elected to the Institute of Medicine of the National Academy of Sciences and was one of the first researchers to investigate diseases that later were linked to the HIV epidemic. His work, which has ranged from malaria research to HIV/AIDS and now COVID-19, has earned him more than 20 major awards in his field.

After his first class with Craig, Quinn requested his advice on next steps for his career. The Vietnam War was raging, and even though Quinn wasn’t explicitly interested in mosquitoes, Craig suggested he complete a M.D./Ph.D. program at Northwestern University. Quinn began work on his dual degree in Craig’s lab. However, by spring 1970, he was called for duty in Vietnam. “I was freaking out. I wanted to go to medical school,” he says. He had already been accepted, and entering medical school immediately provided an exemption from serving — but meant he couldn’t finish the doctoral part of the program.

“I had to tell Dr. Craig that I wouldn’t be completing the Ph.D., and it was such a disappointment for him,” Quinn remembers. “I told him that either I’m drafted or I go to medical school.” Craig put him in touch with a researcher at Northwestern, which allowed Quinn to continue some laboratory research while he was in medical school. “That sort of completed the cycle and to this day, I still run a research lab,” Quinn says, and laughs. “I always loved tropical medicine, and it’s all George Craig’s fault.”

Besansky, Notre Dame’s newest member of the NAS, had only seen Craig once — from across the room at an Entomology Society of America meeting — but his larger-than-life presence still had a hand in her career. She applied to work with him in 1984, and he offered her a fellowship. In the end, she declined. Craig was more interested in mosquitoes’ physiology, ecology and development, while Besansky wanted to explore the use of molecular biology tools in mosquito research. 

Instead she went to Yale to work with Jeff Powell ’69, who was working with genetic tools to understand how Aedes aegypti was susceptible to yellow fever. When she arrived, she discovered that Powell had been one of Craig’s undergraduate researchers. Besansky eventually created one of the first genetic libraries of another mosquito, Anopheles gambiae.

Craig spent a lot of time with students at the University of Notre Dame Environmental Research Center (UNDERC) in Land O’ Lakes, Wisconsin, which is now 7,500 acres of forest and wetland property on both sides of the state line between Wisconsin and Michigan’s Upper Peninsula. Craig had begun using the property for teaching purposes in 1976.

Father Hesburgh also enjoyed the remoteness of the land and fishing its lakes for all species of north-woods fish, including his favorite, muskie. At first, the property was used almost exclusively by Holy Cross priests, but Hesburgh developed a new vision for it as a teaching and research station.

Hesburgh, ever the connector, knew Craig was close with Joyce Hank and her husband, Bernard J. “Jerry” Hank ’51, who were Notre Dame benefactors. Hesburgh eventually invited Jerry Hank to visit the property and get involved with a committee that helped manage it.

Though the property was pristine, living and working conditions there were not. Three or four students lived in each of four minimally appointed trailers parked on a hill. Classes met in a small boathouse building or in a log cabin behind the trailers, says James Elser, who developed his interest in field work during a four-week course at UNDERC after his sophomore year in 1979. “I remember a blue van that was used for transporting students, and we’d jump in the back and we didn’t even have seats,” he recalls.

Craig didn’t ride with the students, Elser says. Instead, he followed closely in his Saab. He’d get out of the car, wearing his “uniform” of a blue shirt and black or navy pants and waders, and tell students where to search for aquatic insects, like stoneflies, caddisflies and other entomological treasures. “He’d be pointing his cane — ‘Go over there! Go over there!’”

Craig had mapped the best spots. “The students would go charging across the field with their waders on and jump into the pond,” Elser remembers. “It wasn’t that different from being a 9-year-old again, discovering aquatic insects for the first time. It was pretty fun.”

A donation from the Hanks helped keep UNDERC pristine while adding a modern laboratory and improved living facilities, including Craig House, the faculty residence. Even before the improvements, UNDERC was “certainly the most important thing that happened to me at Notre Dame,” Elser says. Not only did it introduce him to a career studying lakes, but he also met his wife there, during that course after his sophomore year.

Craig knew how to step outside his campus laboratory and was a constant presence at Notre Dame athletic events. “I remember numerous times going to hockey games, and I would see Dr. Craig across the rink,” John Grieco says. “He’d be banging his cane across the glass. He was at every basketball game and every football game.”

Meanwhile, his research helped Hesburgh realize his vision of a scientifically prominent Notre Dame while garnering the highest honors in his discipline. Ron Hellenthal, who served as director of UNDERC from 1985 to 2000, adds that he and a colleague named a species of chewing louse for him — Geomydoecus craigi, found on a certain kind of pocket gopher.

Craig’s death of a heart attack at the 1995 conference stunned the entomology community, even as many suspected he’d had health issues because of his weight.

Ned Walker had brought his wife and 1-year-old daughter, Monica, to the conference that year, and remembers holding her during the last session of the day. He met Craig’s eyes from across the room, and Craig made a cradling motion with his arms and gave him a smile.

“That evening, we flew back to Michigan, and when I found out he died, I was crushed; I was in tears,” Walker says. “It was quite a shock, because he had been so vigorous. It was very unexpected.”

While taking one’s last breath at an entomology conference might sound appropriate for a career as storied as Craig’s, Grieco suspects his mentor would have preferred to depart this life from a place even more special in his heart. “He loved Notre Dame, and he loved the students,” Grieco says. “He was a true representative of a Notre Dame person, through and through.”

Deanna Csomo McCool is assistant director for marketing communications in the College of Science. Her essay “Total Eclipse” appears in Best American Science and Nature Writing 2020.