Contagious Conversations / Episode 49. On the Case with a Disease Detective
Transcript
Claire Stinson: Your first day at any new job is always a little stressful. But for Julia Petras, the day she started working at CDC was especially high stakes.
Julia Petras: The very first meeting on my calendar of that first day was a briefing with the FBI.
Claire Stinson: It was the summer of 2021, and the country was in the midst of the COVID pandemic, and also a dangerous but little known outbreak.
Newscaster: New warning from the Centers for Disease Control and Prevention and this morning about a deadly disease found in Georgia. Health experts say one person has died from melioidosis. It's been ...
Claire Stinson: A rare disease called melioidosis was making people sick. Some were even dying.
Julia Petras: The very first case was a 53-year-old female from Kansas. The patient had died in the hospital. And then a couple months later, we received the second notification.
Claire Stinson: This time, a four-year-old girl in Texas.
Julia Petras: This person had survived but had significant cognitive deficits.
Claire Stinson: Then came another.
Julia Petras: In Minnesota, a 53-year-old male with a very different presentation of symptoms. This patient had septic arthritis.
Claire Stinson: And another.
Julia Petras: July 24th we received that notification from the Laboratory Response Network in Georgia. And that was the five-year-old boy who had also, unfortunately, passed away.
Claire Stinson: Four patients in four months all sickened by the same mysterious bug, a bug that had no business being in North America in the first place.
Newscaster: Water and soil samples around the cases have turned up nothing.
Newscaster: They say testing shows there's a common source for those cases, and they most closely resemble strains found in South Asia.
Newscaster: The agency is still working to determine how all four people became infected.
Claire Stinson: The FBI and the public wanted answers, and it was Julia's job as an officer in CDC's Epidemic Intelligence Service to figure out how to stop it. This is Contagious Conversations, the podcast from the CDC Foundation, an independent nonprofit that builds partnerships to help the Centers for Disease Control and Prevention and the public health system save and improve more lives. I'm your host, Claire Stinson. Every episode, we hear from inspiring leaders and innovators who make the world healthier and safer for us all. Today, a look at the disease detectives tasked with identifying and stopping infectious threats to public health. CDC's Epidemic Intelligence Service, EIS for short, has been around for more than 70 years. It was started in 1951, just as the U.S. was entering the Korean War.
Newscaster: Tension runs high. Will the United States back down or act?
Dr. Eric Pevzner: At that point in time, there was considerable concern in the United States about threats of biological warfare.
Claire Stinson: That's Dr. Eric Pevzner, the current chief of the Epidemic Intelligence Service at CDC.
Dr. Eric Pevzner: There have been some of our troops getting sick and there had been concerns that the pathogen could be spread through food to our troops and to our people. And it could also potentially be aerosolized and could affect an entire community.
Claire Stinson: The threat inspired CDC's chief epidemiologist, Dr. Alexander Langmuir, to pitch a plan. Here he is being interviewed in 1979.
Dr. Alexander Langmuir: Biological warfare defense was a very hot issue. It was a major propaganda issue in the Korean War. And I argued that if there was anything to this, there was need for epidemiologists.
Claire Stinson: Dr. Langmuir asked for funds to create a training academy for epidemiologists at CDC. When Congress gave him a green light, he started with just four recruits–all men, all doctors.
Dr. Alexander Langmuir: We had the clear charge to recruit and train epidemiologists for civilian and military needs.
Interviewer: And that really was the Epidemic Intelligence Service.
Claire Stinson: Dr. Langmuir was a no-nonsense kind of guy, stern and rigorous. He trained his officers in data collection and analysis, taught them how to go out into the real world, talk to people, get their hands dirty– techniques known as shoe leather epidemiology.
Dr. Eric Pevzner: You got to be on your feet. You got to be out pounding the pavement, and you wear out your shoes doing so.
Claire Stinson: The logo for Dr. Langmuir's Disease Detective Training Service, a man's Oxford shoe with a hole in the sole. Seven decades later, the EIS program has graduated more than 4,000 officers. That's a lot of worn out footwear. Today, more than half of EIS officers are women, and they're not just doctors. These disease detectives come from a variety of backgrounds.
Dr. Eric Pevzner: We also bring in veterinarians. We bring in nurses, microbiologists, physician's assistants, pharmacists, immunologists, anthropologists, speech pathologists. We had a historian two years ago. So we have all these skill sets, these experiences, and incredible expertise so that we're able to respond to ever-increasing complex problems that we have to confront.
Claire Stinson: At every major disease outbreak of the last 70 years, EIS officers have been on the ground investigating AIDS, Ebola, Legionnaires'. When Julia Petras first heard about EIS, she was working as a nurse in a refugee camp in Bangladesh.
Julia Petras: At the time, there was a diphtheria outbreak. And I remember seeing this WHO epidemiologist leading the outbreak response and thinking to myself, "I want to be her one day. She has the coolest job."
Claire Stinson: Oh, and WHO is the World Health Organization. A colleague suggested Julia look into the EIS. Julia decided to go back to school for a master's in public health. A few years later, she applied to join the Epidemic Intelligence Service. But working in the EIS isn't for everyone.
Dr. Jennifer McQuiston: People on the outside might think, ‘Oh, they must be really, really smart scientists. And they must just really like to dig into the data and they want to hole up in their office and just churn out results.’ And that's not actually what defines a good EIS officer, necessarily.
Claire Stinson: Dr. Jennifer McQuiston, principal deputy director in CDC's Division of High-Consequence Pathogens and Pathology. As a former EIS officer herself, Dr. McQuiston has been involved in some of the most high-profile outbreak investigations of the last 25 years. She was also the division's senior lead for the melioidosis investigation.
Dr. Jennifer McQuiston: From my perspective, the best EIS officers I've worked with have wanted to get out and immerse themselves in the field experience. You've got to be really interested in talking to people and engaging with people and pulling the different threads of a puzzle to see where it leads.
Claire Stinson: Julia was accepted into the service in 2021. She moved to Atlanta and joined CDC's Bacterial Special Pathogens Branch. Right away, she was assigned to work on the melioidosis outbreak. It was a tough assignment. Melioidosis is a tricky disease, difficult to diagnose, and deadly.
Julia Petras: It's called the Great Mimicker because it can mimic numerous other diseases.
Claire Stinson: It can be fatal up to 90% of the time if untreated. It's caused by a bacterium called Burkholderia pseudomallei.
Julia Petras: There's still a lot we don't know about melioidosis and Burkholderia pseudomallei, but what we do know is that this bacteria can cross into the brain. It's rare, but it can cause neurological symptoms. It can infect the prostate, it can infect the spleen, the liver. It can literally infect any organ of the body.
Claire Stinson: B. pseudomallei lives in moist soil and freshwater in tropical regions around the world, places like Northern Australia, Thailand and Central America–places none of these four patients had ever been.
Julia Petras: We knew that they were all infected by the same clonal strain of Burkholderia pseudomallei. And we also knew at that point that none of them had traveled outside of the U.S. ever, and that that strain grouped closely to strains from South Asia. We also confirmed that these four patients did not know each other. They had no link of any kind.
Claire Stinson: How was a deadly pathogen from South Asia infecting four unrelated patients in the United States? In a conference room at CDC headquarters in Atlanta, Julia and members of her team tried to find out. The disease detectives didn't have much to go on, so they brainstormed as many possible sources for the infection that they could think of.
Julia Petras: We had a whole list of options that we kept coming back to. We wanted to rule out a hospital-acquired infection. Burkholderia pseudomallei, it's also listed as a tier one select agent in the United States, which means it has a potential to be used as a bioweapon.
Claire Stinson: That explains the call from the FBI.
Julia Petras: It's unusual for cases in four different states, no relation, no travel history. It raises a flag. Could this have been something malicious?
Claire Stinson: Another possibility: something in the environment was making them sick.
Julia Petras: At this point, we had never found the bacteria in the U.S. continental soil. But of course, we thought this could be the first time, so let's not assume anything.
Claire Stinson: Julia and her team did what Alexander Langmuir stressed officers should do when investigating an outbreak, they piled into a car and headed out to test the soil at the home of the most recent patient. They packed roadmaps, field manuals, hundreds of pages of notes, and a good pair of shoes.
Julia Petras: We dug about 30 centimeters down, a foot down, and we took various soil samples from the yard. And we tested them at the lab at CDC for Burkholderia pseudomallei, and none of those came up positive.
Claire Stinson: So the cause wasn't likely to be environmental. Move that down the list.
Julia Petras: We also ended up taking serology of family members of the patients. And we did see that some family members had antibodies against Burkholderia pseudomallei, so that told us that it likely was not a hospital-acquired infection.
Claire Stinson: Meanwhile, the clock was ticking.
Julia Petras: Just knowing that something was out there that was causing children to die was enough to motivate everyone. There was this very palpable sense of urgency to figure out what the cause was. Whatever it was, the source was still out there, not just for this family we were talking to, but for thousands of families potentially across the U.S.
Dr. Jennifer McQuiston: Julia was just really tenacious in this outbreak.
Claire Stinson: Dr. Jennifer McQuiston again.
Dr. Jennifer McQuiston: I remember I came in on a weekend to pick up some papers from my office, and she and her EIS supervisor were holed up in a conference room with a big whiteboard. And they were trying to connect the dots and figure out where to go next and what questions needed to be answered. And they were always trying to pursue getting an answer for that case. And so the tenacity that was required to solve it was really impressive.
Claire Stinson: From the beginning, the team's leading theory was that an imported product had been contaminated with the bacteria, but which product? So the team got in the car again, this time to take a closer look at items in the family's home. Because this bacteria thrives in wet or moist environments, the detectives focused their search there. And in this last patient, the bacteria had gotten into his brain, which led the investigators to suspect it might've been lurking in something he inhaled.
Julia Petras: On that second sampling investigation, we went in with that lens of, okay, let's make sure we get any product that's remaining in this house that could be aerosolized.
Claire Stinson: They rounded up bottles from under every sink and counter, from neem oil to lotions, and took them into CDC for testing.
Julia Petras: Think about what's in your house. It's hundreds of things, so you can imagine our lab team working around the clock testing these commercial products. And the fact that the local health department, the Georgia Health Department, the family, everyone was on board to have us go there and actually interview the family and do our very diligent, thorough investigation was essential and was what ultimately allowed us to identify that product. And it was the aromatherapy spray bottle.
Claire Stinson: Aromatherapy room spray, manufactured in a facility in India that had been contaminated with B. pseudomallei, then bottled, shipped across oceans, and sold through a big box retail store at dozens of sites around the country. Julia was at home when she got the email from the lab with the confirmation.
Julia Petras: ‘Hey, you're not going to believe it. We have a PCR positive confirmation from the aromatherapy spray. We just got the result.’ It was like a complete surprise and a huge relief. And from that moment on, it was high speed.
Claire Stinson: The disease detectives worked with health departments and the other states where infections had been reported. They needed to verify whether those patients had purchased the same room spray. That's when the story took a surprising turn.
Julia Petras: The Texas Health Department, while they were confirming with the family about the receipt of this product, the family mentioned that their pet had died of an unknown cause about a month before their little girl got sick.
Claire Stinson: The family had purchased the same spray. They said their pet cat had knocked the bottle over, spilling the liquid on the floor, and walking through the spilled contents. Days later, it developed neurological symptoms and died. The family buried it in their yard.
Julia Petras: The last thing we wanted was a decomposing animal carcass to somehow contaminate and seed the environment with a very deadly tropical bacteria.
Claire Stinson: Julia packed her bags again and flew to Texas, where she met up with a fellow in EIS's sister program, the Laboratory Leadership Service. A team had assembled there to exhume the pet's body with the family's permission.
Julia Petras: The LLS fellow, Maureen Ty. She was based in the Dallas Lab at the time. And we worked with the EPA, who was with us.
Claire Stinson: EPA. That's the Environmental Protection Agency.
Julia Petras: Our EPA colleagues had a backhoe, a huge machine that we used to actually dig this animal out.
Claire Stinson: Both the carcass and the soil would need to be tested for contamination. The crew worked carefully, sifting through layers of dense Texas clay looking for cat-sized remains.
Julia Petras: When we saw how large the animal was, we knew it was definitely not a cat. The paws were a big giveaway.
Claire Stinson: The family pet turned out to be a raccoon.
Dr. Eric Pevzner: And I was just kind of floored.
Claire Stinson: When the team called Dr. Pevzner back in Atlanta, he was surprised. You never know what's going to happen on any investigation.
Dr. Eric Pevzner: I love when I get those calls from officers that kind of knock me off my chair. It keeps me on my toes.
Claire Stinson: He says the incident highlights how important it is for officers to work closely with local and state health officials, all part of the network that makes up the public health system.
Dr. Eric Pevzner: The family felt comfort in saying, ‘Yeah, we know we weren't really supposed to have this pet raccoon, but our concern for the public is greater than that.’ That's about Julie and the state and local health department staff building that trust.
Claire Stinson: Luckily, the team found no evidence that the soil had been contaminated with the deadly bacteria, but lab tests soon confirmed the raccoon's cause of death.
Julia Petras: So we could safely say this was our fifth case and the first documented raccoon to have melioidosis.
Claire Stinson: Now that the product was identified, CDC and the Consumer Product Safety Commission work to get the room spray taken off store shelves.
Newscaster: An important consumer alert we want to bring you now. The Centers for Disease Control's investigation into a cluster of illnesses and deaths zeroing in on a $4 product, essential oil room spray.
Newscaster: A superstore is recalling room spray that may contain a rare and potentially deadly bacteria. If you have it at home, the CDC says you should immediately stop using it, keep it closed, and return it ...
Claire Stinson: It was the kind of moment that makes Dr. Pevzner proud to lead the program Dr. Langmuir founded all those years ago.
Dr. Eric Pevzner: That was what Alexander Langmuir was teaching EIS officers in 1951. Those basic interviewing skills, that descriptive epidemiology, asking comprehensive questions, and narrowing and shifting to try and figure out what that might be. That saved countless lives.
Claire Stinson: And that work continues. Right now, there are 135 EIS officers, disease detectives, investigating disease outbreaks across the United States. About a third of those are embedded with state and local health departments. The rest work at CDC's regional facilities or at the headquarters in Atlanta. After completing their two-year training, many graduates go on to distinguished careers in public health. Many become state epidemiologists, and four EIS alumni have become CDC directors. It's a job that Dr. Pevzner says isn't getting any easier.
Dr. Eric Pevzner: Being an EIS officer is more difficult than ever. The greater movement of people all around the world means that pathogens can also move much more quickly. There's much greater opportunity for things to spread. So the skill sets required of officers are far greater than it's ever been.
Claire Stinson: He says the officers of the future will include not just doctors, epidemiologists, and veterinarians, but also computer programmers and data engineers. Thanks to advances in computing and data collection, EIS officers can spot emerging health threats faster and better coordinate the response.
Dr. Eric Pevzner: As a disease detective, you get to go and figure out how can you help protect people so that you can give people the opportunity to have healthy lives. And there's nothing more rewarding than getting to do that as a disease detective at CDC.
Claire Stinson: Julia Petras finished her EIS rotation in 2023 and is now an epidemiologist with CDC's Global Influenza Branch.
Julia Petras: Welcome to my funky house.
Claire Stinson: At her home in Atlanta, she still keeps memories on her mantelpiece from her time as an officer.
Julia Petras: I won this award for the aromatherapy outbreak at EIS Conference.
Claire Stinson: An award from the EIS Alumni Association.
Julia Petras: And this is my EIS coin that they give ...
Claire Stinson: A ceremonial coin she got at her EIS graduation.
Julia Petras: Oh yeah. This is our New England Journal of Medicine paper ...
Claire Stinson: Two studies published in the New England Journal of Medicine, a once-in-a-lifetime accomplishment for most researchers. She says joining EIS was one of the best decisions she's made.
Julia Petras: It's made me a better epidemiologist. It's given me skills that I probably would've taken me decades to learn. This was definitely the largest impact that I've ever been able to have, for sure. I mean, we're talking about something that affects an entire country, potentially the world.
Claire Stinson: The threat from B. pseudomallei hasn't been eliminated completely. The bacteria has been found in other locations in the U.S. In fact, CDC continues to investigate cases in the Southeast. It shows that an epidemiologist's work is never done, but Alexander Langmuir's vision remains as vital as ever.
Julia Petras: There is no replacement for shoe leather epidemiology. You can have all of your advanced biostatistics, your sophisticated software, but it doesn't replace the importance of talking to real people, to being physically there doing some of that boots-on-the-ground detective work. There is no replacement for that.
Claire Stinson: Thanks to CDC's Julia Petras, Dr. Jennifer McQuiston, and Dr. Eric Pevzner for talking with us for this episode. Maya Kroth was the show's producer. And thanks for listening to Contagious Conversations, produced by the CDC Foundation and available wherever you get your podcasts. Be sure to visit cdcfoundation.org/conversations for show notes and photos from Julia's investigation. Up there, we'll also have a link to the full groovy 1979 interview with EIS Founder Alexander Langmuir.
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