This commentary was written by Martin Nielsen, DVM, PhD, Dipl. ACVM, associate professor and Schlaikjer Professor of Equine Infectious Disease, at the University of Kentucky (UK) Gluck Equine Research Center.


This year, 2017, was a sad one for veterinary parasitology. Two of the world’s most recognized scientists in their field—Dr. Eugene T. Lyons (PhD) and Ms. Sharon C. Tolliver—recently passed away, marking the end of an era. The parasitology research program at UK celebrated its 70th anniversary in 2017. Of these 70 years, Gene Lyons and Sharon Tolliver worked here 56 and 52 years, respectively. In other words, they were the research program. And each remained active at the University of Kentucky until their death.

They influenced and were appreciated by colleagues around the world who had the opportunity to know and work with them—students, postdocs, visiting scientists, and countless other individuals in the equine and veterinary industries who worked and interacted with them over the decades.

They had a unique working relationship and did most things together, including farm visits to collect fecal samples, postmortem work with parasite specimen collection and identification, and writing manuscripts. Gene would draft the paper, and Sharon would proofread it and organize the references. During farm visits, Gene would go into the stall to collect a fecal sample from a horse, and Sharon would mark the sample off on the clipboard and keep all samples organized. They worked together in symbiosis.

Sharon was one of very few experts in the world on microscopic identification of helminth parasites and she co-authored more than 200 research publications. Her monograph describing morphological characteristics of equine small strongyle (cyathostomin) parasites in her own down-to-earth language remains as an incredible monument to her expertise and significance as a scientist.

What was really remarkable about Gene and Sharon was how they both loved interacting with students and young, aspiring researchers. The list of students, visiting scientists, and collaborators who had the opportunity to come and spend time with them is extremely long. I, myself, was one of probably several hundred who had the wonderful experience of being taken under their wings when I first came to the Gluck Center many years ago. Gene was my tour guide and drove me around the Bluegrass state, determined to show me how unique this area is, and he took me to well-selected local restaurants to make sure I got to taste the local Southern cuisine. Sharon took time to show me all of her small strongyle parasite specimens, and talked about how one particular species had features resembling “dangling duck feet” and how the male of another species was her favorite because he was “so handsome.” And then she would make sandwiches for us right there in the lab. I am sure that many people reading this article have very similar experiences with them. It felt like they welcomed me to a family.

It has always struck me how helpful they both were. They were never too busy to demonstrate a technique or show a particular parasite specimen from their valuable collections. Very typical for Gene, whenever asked a question, he might not come up with a useful answer right away, but within a day, he would bring a pile of papers or Internet links with useful information about the given topic. I happen to have one such stack right here on my desk, as I asked him a question just two days before his passing. The term “walking encyclopedia” is a cliché, but it describes Gene well. He was such a resource to our program. A go-to person. “Go ask Dr. Lyons,” was often my response to my students whenever they were struggling with a question. And, they would sit down and talk with him for hours.

One of my greatest pleasures of working with Gene was through the students we shared. I have enjoyed how many of these students, after completing a visit or graduating from the university and going elsewhere, have said that meeting and interacting with Dr. Lyons was the best of all the experiences they had here. These days, social media are loaded with pictures of Dr. Lyons with these young people. As I look at them, I see him smiling, laughing, and clearly enjoying himself in each and every one of them. Yes, Dr. Lyons was enjoying life. He had a passion for work—seven days a week, year-round, no vacations—but, he loved and cherished these interactions with people. Not just with students, but farm personnel, veterinarians, farm managers, and collaborators around the world. Dr. Lyons was a people person.

It is hard to adequately describe Gene’s and Sharon’s scientific contributions. Gene published more than 300 research papers, and he was working on new manuscripts and research ideas when he passed. Major milestones include the description of lactogenic transmission of the equine threadworm, Strongyloides westeri. For his PhD, he unraveled the life cycle of a hookworm parasite of sea lions and described how the pups were infected through the colostrum while suckling. Upon his arrival in Kentucky in 1963, he was determined to investigate the threadworm life cycle as he was suspicious that a similar mode of transmission could be in play for this parasite. It took him 10 years of hard work to document this. He would wait by the phone day and night to have farm managers call him whenever a mare had foaled, then drive out to the farm to get a colostrum sample in the middle of the night. For a long time he did not find a single parasite larva in those samples. At this point, most people would have rejected that hypothesis and focused their time on other projects. But, very typical for Dr. Lyons, he just kept going. Instead of focusing on the colostrum, he decided to get milk samples representing the first couple of months of lactation from a large number of mares, and one day he found the first parasitic larva. In 1973, he published a milestone paper describing these findings, which were unprecedented at the time. He received the Thomas Poe Cooper Award for this work in 1976.

Dr. Lyons made many more significant contributions together with Sharon, Dr. Harold Drudge (DVM, ScD), and their other long-time technician Sandra Collins. They described the life cycles of the eyeworm, Thelazia lacrymalis, and the bloodworm, Strongylus vulgaris. They tested and evaluated every single equine dewormer that ever made it to the market, and a lot of those that didn’t. They documented the presence and propagation of drug-resistant parasites, and they meticulously tracked and described changes in prevalence and abundance of important equine parasites across more than five decades.

In addition to this, Dr. Lyons is also a world authority on parasites infecting seals, sea lions, and other pinnipeds. He made strenuous field trips out in the wilderness to visit remote locations all over the world to study these animals and their parasites. He had a great passion for everything biological and these trips, however demanding, were near and dear to his heart. One great memory is when he decided to give a presentation to the entire department describing his sea mammal work. He gave a wonderful talk with beautiful images from all of his trips. He had sound clips and videos. It was just amazing how passionate he was, and we were all left in awe. He will forever serve as a role model for me and, I am sure, many others, as well.

Both Gene and Sharon were widely recognized across the world for their expertise. Sharon was inducted into the Pendleton County School System Wall of Fame in 2006. In addition to the Thomas Poe Cooper Award, Dr. Lyons was also co-recipient of the 1991 American Association of Veterinary Parasitologists Distinguished Veterinary Parasitologist Award together with his research companion, Dr. Harold Drudge. Last, but not least, Dr. Lyons was inducted into the Equine Research Hall of Fame in 2012.

Gene and Sharon were classical parasitologists par excellence, and their passings mark the end of an era. An era that gave us the biological information that we take for granted today, and an era which revolutionized how parasite control is approached today. It must have pleased them both to witness how classical deeds never went out of fashion. We may have nanotechnology, DNA and RNA sequencing, and bioinformatics, but at the end of the day someone has to be able to identify that parasite and describe how it develops within its host before we can apply all these new technologies. Gene and Sharon have passed these skills onto us, and we are forever thankful. It is now up to us, in the new era, to combine these disciplines in multidisciplinary projects to further advance our knowledge about parasites and provide and expand the tool set we need to adequately control them.

We have lost two extremely hard-working and very dedicated people. They were extremely skilled, passionate, and compassionate. They leave an incredible legacy and we are forever grateful to have known and worked with them. Their contributions will never be forgotten, and we are dedicated to continuing the parasitology research program that they founded and built so successfully. Dr. Lyons remained curious and enthusiastic to his last day. One statement often made by Dr. Lyons keeps resonating in my head, and let this statement be our mantra as we walk in his footsteps:

“You can always learn something new” Gene Lyons


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