Subject Matter Expert Q&A: Epidemiology with Dr. Michele Jay-Russell
PMA’s Chief Science & Technology Officer, Dr. Bob Whitaker interviewed epidemiology expert, Dr. Michele Jay-Russell to introduce her to PMA members and provide a snapshot of her background and her passion for epidemiology.
BW: What drew you into epidemiology?
MJR: My interest in epidemiology probably started as a kid. I was always curious about animals and nature. I did my own little epi-investigation as a kid into die off of tadpoles in our neighborhood pond. After doing interviews, I discovered it was because a neighbor was putting gasoline and doing some dumping in the pond. So that was stopped. I always had a curiosity, and going into my education I was very interested in applying to veterinary school, but I didn’t take the traditional route as an undergrad. I went through medical entomology and theater as well as focusing on writing. Eventually I went into vet school and at UC Davis they have a combined program in preventive medicine and epidemiology, so I signed up for the duel degree program and knew that I would ultimately end up having a role in public health and doing epidemiologic investigation.
BW: What do you think is most misunderstood about the role of epidemiology in public health and the combination of art and science that makes up its practice? You did a great job writing these two companion papers, but what do you see most often as industry misperception of what epidemiology does?
MJR: I think the misperception relates to the strength of the association and the understanding of how statistics can be used. Having the science of epidemiology isn’t as straight forward as having for example a laboratory test. Not that all microbiology test are unambiguous but it is a lot easier to understand that you cultured E. coli O157:H7 out of a food or you didn’t versus discussing the nuances of an epidemiology investigation where you have outliers and statistical criteria. You have people that ate the contaminated food and didn’t become ill, and people who appeared not to have eaten the food and are part of the community and had an exposure. So the level of uncertainty in epidemiology is much greater than what you typically find in a standard microbiological test. Also, along that line, there is an expectation by some in the industry that you are always going to truly prove the cause of a foodborne outbreak. Sometimes that is just not possible because of the perishability of our products and the sampling limitations for testing for pathogen presence. You have to rely on epidemiology and not having that laboratory result should not ever be an excuse not to protect public health if your epidemiology is strong. Where things get difficult is that not all epidemiology investigations are the same. Some are stronger than others, some have weakness and uncertainty.
BW: Is there anything that makes fruits and vegetables more difficult when doing epidemiological studies versus another food group? I know that you have been involved across the board in different food groups. Is there anything about produce that is particularly different or any key learnings that you have gained over the years in cases where fruits and vegetables have been involved?
MJR: The difficulty can be when you have an emerging vehicle or any food product that has not been seen before with a certain bacterial pathogen. For example, when strawberries were implicated with E coli. O157 earlier this year, that was not an expected vehicle. Also early on with sprouts, it took a number of repeated epidemiological studies before sprouts were actually linked to outbreaks. Some of that work was done in California by some of my colleagues, and one of their major clues was having a disproportionate number of women that were eating that produce item. The other part relates to what I was saying about having laboratory evidence. With milk, dairy, produce, and those items by time you identify the outbreak and start interviewing people that product can be long gone. And because contamination can be intermittent or in a short period of time, not ongoing, you may never isolate the implicated strain out of the food product.
BW: Ok switching gears, you just recently completed a PhD at UC Davis correct?
MJR: Yes, I did.
BW: Can you describe to PMA members what your current research interests are and how does that relate to some of the work you have done recently in the epidemiological field?
MJR: Well currently I am working as the project director in the Western Center for Food Safety at UC-Davis. I have been in this position for a little over 3 years now. The center was created with FDA to be what they call a “center for excellence” and is funded by CFSAN. Our center focuses on the interface with animal and plant agriculture as well as the environment. We in particular focus on pre-harvest food safety with an emphasis on produce. There is some dairy but the dairy component relates more towards manure management. So we do have strong produce research effort right now. Because I am a veterinarian, with a background in epidemiology, I am doing studies that primarily look at domestic and wild animals, and whether or not they are carries of foodborne pathogens, and what potential risks and mitigation strategies are available to prevent direct transmission of pathogens onto produce plants out in the field or to protect watershed from contamination by animals.
BW: Thanks Michelle. Also, thank you for preparing two excellent papers on epidemiology. These papers can be found on pma.com in the “Information” section of the Food Safety Resource Center.