By Richard Levine
I recently had an email discussion with Trevor Burt, co-editor of the newsletter for the Entomological Society of Ontario, about the field of medical entomology.
“I feel that medical entomology is not featured enough or discussed enough in the society meetings and conferences,” he wrote. “It has been overlooked in favor of taxonomy and physiology, and I think it’s time to broaden our scope and introduce a fresh perspective.”
This was news to me, and I volunteered to help out. As we’ve written before at Entomology Today, diseases vectored by insects have historically killed more people than bombs or bullets, and medical entomologists are trying to do something about it.
Dr. Fiona Hunter, a medical and veterinary entomologist at Brock University, was nice enough to answer my questions about medical entomology, especially about how it is practiced in Ontario, Canada. My interview with her follows.
Richard Levine: How does a medical entomologist differ from others as far as education is concerned?
Fiona Hunter: A medical and veterinary entomologist is someone who studies insects (and arachnids) that can potentially harm or transmit diseases to humans and animals. This includes both domestic and wild animals. In Canada, where there are very few remaining entomology departments, it is exceedingly difficult to get formal training in medical entomology. In the U.S., one can actually get a degree in medical Entomology!
I was fortunate to have studied at a variety of different universities in order to gain all of the training that I needed, but it took many years. My BSc was in zoology from the University of Toronto, where I got a solid grounding in whole organism biology, invertebrate biology, entomology, evolution, and ecology.
I also did an MSc at their Botany Department so that I could work on black fly cytotaxonomy and systematics under the late Dr. Klaus Rothfels. He was a terrific mentor and arranged for me to spend a year at the Tropical Medicine Institute at the University of Tübingen in Germany, where I took parasitology and worked in a lab with a World Health Organization black fly research group that studied the role of black flies in the transmission of onchocerciasis (also known as river blindness).
I completed my PhD in biology at Queen’s University under the co-supervision of Dr. Jim Sutcliffe, a black fly physiologist, and the late Dr. A. E. R. Downe, a mosquito physiologist. Essentially, I had to cobble together my own credentials. Today, it is even more difficult for aspiring medical and veterinary entomologists to get the training they need without traveling to the U.S. for their studies.
Richard Levine: So a degree in medicine is not required?
Fiona Hunter: No, it’s absolutely unnecessary. We collaborate with medical experts, but I really find it far more challenging to study the insects and the diseases they transmit from the insect’s perspective.
Richard Levine: You wrote to me that “taxonomy is still the cornerstone of our research — morphological, chromosomal and/or molecular.” That surprised me a bit because I pictured medical entomologists as being more involved with actual medicine. Can you tell us a bit more about this?
Fiona Hunter: Often people — including many medical doctors — think that a mosquito is just a mosquito, but that is the farthest from the truth! In Canada, for instance, there are 82 different mosquito species, and each one has its own life history traits. One species never takes a bloodmeal and spends its entire life associated with pitcher plants. Another species preferentially feeds on amphibians, and although it may have enormous larval populations, would never harass humans, nor present a danger of disease transmission to humans.
Because there are so many different species of biting insects, it is essential that we are able to identify them correctly to determine whether they present a threat or not. That is why taxonomy is the cornerstone of our research. My preference is for good, old-fashioned methods of identification based on structural traits. However, the number of trained taxonomists is also dwindling in Canada — there used to be several entomologists in Ottawa at the National Collection who were experts in biting flies, but as these people retired, they were not replaced. Therefore, we participate in establishing molecular tools for identifying the insects so that other researchers can ensure that their identifications are correct.
Richard Levine: To be called a medical entomologist, must you work on insect-borne diseases, or is it enough to simply conduct research on insects that are considered to be medically important, like mosquitoes and flies?
Fiona Hunter: For many years I worked in Algonquin Park and did not really concentrate on any important diseases, except a bird malaria that is transmitted to waterfowl by bird-biting black flies. My students and I were able to study nematodes that infect black flies and even cause feminization of behaviors in infected male black flies. We also studied sugar-feeding preferences of mosquitoes, deer flies, horse flies, no-see-ums (to determine where they get their flight energy from), and so forth. In the lab, we studied rodent malaria transmitted by a species of Anopheles mosquito that isn’t even found in Canada.
All of this research is what I would call “baseline” research. It wasn’t until West Nile virus hit Ontario that we swung into full gear looking at a disease that was actually affecting people here in Canada. Without all of the previous baseline research that my lab had been doing, it would have been impossible to do the “applied” research to determine which species of mosquitoes were carrying West Nile virus.
Richard Levine: I read that you have a level 3 containment lab in order to study mosquitoes infected with West Nile virus. Was it difficult to build such a facility, and what’s it like to work in it?
Fiona Hunter: I asked Brock University if it would be possible to build a level 3 lab back in 2002, and it took just over a decade to get the funding in place and to get the facility built, certified, and up and running. We are the only CL3 with an insectary outside of the National Microbiology Lab in Winnipeg, so we are very fortunate to have this facility. I currently have five students who work in the CL3 on West Nile virus. The really exciting thing is that we are now prepared to tackle the next emerging vector-borne disease to hit Ontario — and, of course, it is just a matter of time before that happens!
Richard Levine: You mentioned that one of your students is “barcoding” an invasive ceratopogonid species. What does that entail exactly, and how is it useful?
Fiona Hunter: Another graduate student of mine has the skills (and patience) required to do morphological taxonomy on Ceratopogonidae (or “no-see-ums”). In the first year of his studies, he discovered that there was a species in Ontario that is of veterinary importance. This species was not supposed to be as far north as Ontario, so he is working on a number of different molecular tools to be able to differentiate it from local ceratopogonids so that others can use his toolkit to conduct surveillance for this species.
Richard Levine: You also mentioned working on malaria in Ecuador. Were you in a lab or out in the field, and what kind of things were you researching?
Fiona Hunter: I had a graduate student (now graduated) who did three summers’ worth of field research in Ecuador to determine the distribution of malaria mosquitoes in that country. Again, morphological and molecular tools were used, and she was also a whiz at GIS, so she was able to map everything beautifully.
Richard Levine: I read an article that said you were “one of the few remaining medical entomologists in Canada.” Is that true, and if so, why are there so few?
Fiona Hunter: I think it’s because we don’t really have training in Canada, and as old medical entomologists at universities retired or died, they were not replaced. Also, the CNC did not replace its experts in biting flies. There used to be a Biting Fly Centre in Winnipeg, but its doors were closed decades ago. It’s as if the “powers-that-be” decided that Canada no longer had a biting fly problem, or that there was nothing new to learn about them. That was very short-sighted.
Richard Levine: Is medical entomology in Canada (or in Ontario in particular) in any way different than in the United States?
I think there actually are quite substantial differences in Ontario vs. the U.S. For instance, we do not really have public support here for using adulticides to kill vector mosquitoes. In the U.S., it has been quite a common practice over the years to use aerial insecticides to kill nuisance mosquitoes, and there are many mosquito control districts in the U.S. Thus, when there are West Nile virus scares, it doesn’t take much for aerial insecticides to be used.
In Canada — the exception being in Winnipeg, where they’ve had nuisance mosquito control for decades — the public is not used to aerial insecticides being used. As a result, even in the 2002 and 2012 West Nile epidemics in Ontario, no adulticiding was done.
Overall, medical entomologists in the U.S. are far more involved in making mosquito control recommendations than we are here in Canada. For the record, I don’t think the Canadian situation is a bad thing. Let people with proper training and research experience in pest control make those recommendations!
Read more about Dr. Hunter at:
Richard Levine is Communications Program Manager at the Entomological Society of America and editor of the Entomology Today Blog.