Celebrating World Field Epidemiology Day
Wait, what is a field epidemiologist?
I have two posts I need to write, one for world field epidemiology day, and one for public health lab appreciation month. Since I have a few more weeks left in September, I’ll start with the field epi and do the lab celebration next post. So lets jump into field epi appreciation!
What is a field epidemiologist?
We should start with the most basic question - what exactly is a field epidemiologist, and how is that different than any other type of epidemiologist? Field epidemiology can also be known as applied, or interventional epidemiology, and the hallmark of field epidemiology is that the focus is on response, action, and intervention. In contrast to academic epidemiology where studies can be carefully planned in advance, field epidemiology involves collecting data and drafting the study and analysis plans in the moment, and evolving these as needed to the changing situation data availability. Much of this post is inspired by the below paper - thanks to the authors for a great description of field epidemiology, and you should definitely go read the whole paper.
Field epidemiology in action
I showed up for my first day of work as a field epidemiologist full of knowledge gained through my MPH program, and also woefully unprepared for actually applying that knowledge in practice. My first job was as a district epidemiologist at a local health district, where I was the one infectious disease epidemiologist covering 7 counties. Despite the large number of counties and large area of land I covered, there were only about 112,000 people in the district - pretty rural!
I jumped right in on my first week with a call from a hospital about an invasive Group A Strep infection. It was a particularly severe necrotizing fasciitis case and after consulting our internal disease control guidelines as well as my “Control of Communicable Disease Manual” I contacted the family and did an assessment to determine whether any high-risk individuals might need antibiotic prophylaxis. This was my first experience of learning how to become an instant expert on communicable disease investigation and control, one disease at a time. The skill of learning how to learn quickly and tap into the right resources was a key one for me to learn early in my career.
Group A Strep came back again soon after, this time with a much more concerning event of an invasive infection in a long-term care facility. After assessing (along with a regional epidemiologist) and making recommendations for some changes in cleaning and infection control practices, we eventually made the decision to do screening swabs of residents and staff. This introduced me for the first time to one of the biggest challenges in field epidemiology: logistics. Not only did I have to coordinate with the facility to have nurses available, I had to coordinate with the labs (the local hospital lab did the initial culture, and then positive cultures went to the public health lab) to ensure we had the right specimen collection supplies, arrange specimen transport, and organize all the reported results. This lesson was reinforced again during the COVID-19 pandemic - logistics is the most important piece of field epidemiology that you aren’t taught in school! The investigation stretched on for many months, and I often spent time in a conference room surrounded by stacks of medical records to review. Another lesson I learned from this outbreak was the importance of building rapport - part of the reason I had excellent compliance from the facility on recommendations was because they saw me there working side-by-side with them, and grew to trust my advice.
Other outbreaks I worked in included Hand, Foot and Mouth Disease (HFMD) in a couple of universities - that was a fun one! I have to say that college students are my favorite to interview, they tend to be very candid and share exposures freely (“I kissed a person that I didn’t know in a closet at a party”). Kissing is a great way to spread HFMD! Food histories from students could also be interested: what did you have for breakfast? Beer. What did you have for lunch? Beer. What did you have for dinner? Beer. Hmm, I’m not sure how they got Salmonella, but some dietary changes are probably advisable.
Some of my favorite outbreaks involved working with the public health veterinarians. As part of one live poultry Salmonella investigation I tagged along to observe collections of swabs from some chickens and ducks. What I thought was observation quickly turned into a lesson, and the next thing I knew I was searching through a mass of feathers to find a chicken cloaca to swab. Those things are really hard to find! Maybe not for a vet, but for an epidemiologist it was a new experience!
I spent a lot of time working on foodborne outbreaks, and it’s not always straightforward to decide when evidence is strong enough to take action. One particularly memorable outbreak involved cucumbers. We were weighing evidence from the laboratory (that this cluster of cases was closely related to one another), from our patient interviews (most people ate cucumbers), and from product traceback information (cucumbers were tracing back to a particular farm). There is no SOP or statistical cutoff value that can define for you what combination of evidence is enough to take action (in this instance a press release about the outbreak). This unique skillset of bringing together different strands of evidence to make good decisions about public health action is critical for field epidemiologists to master in order to be effective.
While working at the interface between many specialties involved in addressing public health problems, we need to cherish our distinct macro-perspective and skills, to effectively synthesise wide-ranging pieces of evidence, as well as a pragmatic and flexible ‘can-do’ mindset and use of practicable methods inherent in field epidemiology.
Hahné Susan, Hammer Charlotte, Tostmann Alma, Whelan Jane, Williams Christopher. Field Epidemiology: Fit for the future. Euro Surveill. 2023;28(36):pii=2300347. https://doi.org/10.2807/1560-7917.ES.2023.28.36.2300347
Working as a field epidemiologist is exciting, interesting, and sometimes overwhelming. Though we don’t deal directly with tragedy the same way as clinical colleagues, there were many times where I had to work on really emotionally challenging cases and outbreaks. A woman who lost her pregnancy due to Listeria but took the time to help me collect all her food history information, a man who lost his wife to Legionella but helped me pinpoint possible exposure sites for investigation, a woman who lost her husband to SARS-CoV-2 and then watched her baby be hospitalized for the same thing. When you interview the patients and families, hear their stories, and invest yourself in solving the outbreak so that no others will have to go through the same pain, it is simultaneously rewarding and heartbreaking.
Field epidemiology into the future
I’m going circle back with another quote from the paper I’ve been referencing, as I think this summarizes one of the key points about field epidemiology looking forward.
Previously, we worked mostly with public health experts, clinicians, mathematical modellers, statisticians and behavioural experts. We now must expand our vocabulary, be comfortable with the terminology of a growing and diverse range of other disciplines, and leverage the expertise of data scientists, geneticists, bioinformaticians, infodemiologists, privacy experts, lawyers, artificial intelligence experts, IT-experts and software developers.
Hahné Susan, Hammer Charlotte, Tostmann Alma, Whelan Jane, Williams Christopher. Field Epidemiology: Fit for the future. Euro Surveill. 2023;28(36):pii=2300347. https://doi.org/10.2807/1560-7917.ES.2023.28.36.2300347
As the universe of data has expanded, so has the need for field epidemiologists to grow their networks and spheres of expertise. Incorporation of genomics into field epidemiology is my area of special focus, but the authors point out many other fields that are just as critical as well. All of this points to the growing need for well-trained field epidemiologists who are fully supported throughout their career, and able to access the continuing education and training needed to effectively fulfill their role as information integrators and practical decision-makers.
There is much to look forward to in the coming years for field epidemiology, and I hope my work helping field epidemiologists incorporate genomic data will contribute to the overall continued advancement of the field. Thanks for reading, and go thank a field epidemiologist today!