Picture of Dr. Maarten Voordouw

Dr. Maarten Voordouw BSc, PhD Assistant Professor, Veterinary Microbiology

I am an assistant professor in the Department of Veterinary Microbiology at the WCVM as of July 2018. Our research group studies the ecology of ticks and tick-borne diseases in Canada.

Address
Western College of Veterinary Medicine, University of Saskatchewan 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4 Canada

Biography

My research interests include host-parasite interactions, vector-borne diseases, multiple-strain pathogens and the ecology of mixed infections, Lyme disease and other tick-borne infections. From 2011 to 2018, I was an assistant professor in the Institute of Biology at the University of Neuchâtel in Neuchâtel, Switzerland where my research was focussed on the ecology of Lyme disease. From 2009 to 2010, I was a postdoc in the lab of Dr Dustin Brisson at the University of Pennsylvania in Philadelphia, USA. This postdoctoral experience introduced me to the world of ticks and tick-borne diseases.

Education

BSc Biology, University of Victoria, Canada

PhD Biology, University of Victoria, Canada

eTick

This year, we are using eTick to monitor tick bites on people and their pets in Saskatchewan. This program allows Saskatchewan residents to use their smartphone to photograph their ticks and submit these photos using the online eTick system (https://www.etick.ca). Researchers at the University of Saskatchewan will then identify the tick species, which is important for knowing the risk of different tick-borne diseases (e.g. Lyme disease). For more information on the history of monitoring ticks in Saskatchewan, visit our site on tick surveillance (https://research-groups.usask.ca/ticks/).

Research Area(s)

Research Topics

 

Study system: My research is focussed on the ecology of Lyme disease. Lyme disease is the most common vector-borne disease in the northern hemisphere (~130,000 human cases per year). The causative agents of Lyme disease are spirochete bacteria that belong to the Borrelia burgdorferi sensu lato (sl) genospecies complex. Ticks in the genus Ixodes transmit these tick-borne pathogens between vertebrate hosts. The main reservoir hosts for B. burgdorferi sl include small mammals and birds whereas humans, companion animals, and livestock are accidental hosts. Below I describe current and past research topics of interest.

 

The factors that maintain strain diversity in pathogen populations (current and future research topic): Many pathogen populations consist of genetically diverse strains. A fundamental question is to understand the ecological factors that allow this strain diversity to persist. Lyme borreliosis (LB) is caused by a tick-borne spirochete bacterium. In areas where LB is endemic, the ecosystem often contains a dozen or more strains. Using a long-term field study in Neuchâtel Switzerland, we showed that the local population of ticks contained over 21 different strains of the most common LB pathogens (B. afzelii and B. garinii). Some strains are persistently common whereas other strains are persistently rare, and we want to understand why [1, 2]. There is substantial variation in transmission efficiency between strains of B. afzelii, which is related to their frequency in the field [2, 3]. Strain diversity in pathogen populations can have important implications for public health such as diagnostics and vaccine development. The study of this genetic diversity can help with the development of effective control strategies.

 

Strain-specific immune responses and strain diversity (current and future research topic): The immune response in the vertebrate host plays a critical role in mediating interactions between strains and in maintaining strain diversity. We are interested in using Borrelia burgdorferi pathogens as a model system to study how the strain-specific antibody responses of the vertebrate host maintain strain diversity in nature. We showed that female bank voles transmit strain-specific antibodies to their offspring that protect them against ticks that are infected with the same strain but not against ticks carrying a different strain [4]. This intergenerational transfer of strain-specific immunity could play an important role in reducing competition between strains and in maintaining strain diversity.

 

Interactions between pathogen strains in mixed infections (current and future research topic): Mixed infections or co-infections are when a host is infected with multiple pathogen strains. In mixed infections, interactions between strains can have important consequences for the transmission success and prevalence of individual strains. We used the tick-borne pathogen, Borrelia afzelii, as a model system to study interactions between strains in both the vertebrate host and the arthropod vector. We have shown that mixed infections are common in wild ticks [1, 5]. We used experimental infections to show that competition between strains reduces their host-to-tick transmission success and their abundance in the tick vector [6, 7]. We are investigating whether co-infection in the tick vector influences the strain transmission success from the tick to the host.

 

Co-feeding transmission (past research topic): Co-feeding transmission of vector-borne pathogens occurs when the vector is transferred directly between arthropod vectors that feed in close proximity to each other on the same host. This mode of transmission has been demonstrated in a number of vector-borne pathogens such as West Nile virus, tick-borne encephalitis virus, and LB pathogens [8]. Our research group has made a number of contributions to co-feeding transmission of LB pathogens [3, 8, 9, 10].

 

References

 

  1. Durand J, Jacquet M, Paillard L, Rais O, Gern L, Voordouwa MJ. Cross-immunity and community structure of a multiple-strain pathogen in the tick vector. Appl Environ Microbiol. 2015;81 22:7740-52.
  2. Durand J, Jacquet M, Rais O, Gern L, Voordouw MJ. Fitness estimates from experimental infections predict the long-term strain structure of a vector-borne pathogen in the field. Scientific Reports. 2017;7 1:1851.
  3. Tonetti N, Voordouw MJ, Durand J, Monnier S, Gern L. Genetic variation in transmission success of the Lyme borreliosis pathogen Borrelia afzelii. Ticks Tick Borne Dis. 2015;6 3:334-43.
  4. Gomez-Chamorro A, Heinrich V, Sarr A, Roethlisberger O, Genné D, Bregnard C, et al. Maternal antibodies provide strain-specific protection against infection with the Lyme disease pathogen in bank voles. Appl Environ Microbiol. 2019:AEM.01887-19.
  5. Durand J, Herrmann C, Genné D, Sarr A, Gern L, Voordouw MJ. Multistrain infections with Lyme borreliosis pathogens in the tick vector. Appl Environ Microbiol. 2017;83 3.
  6. Genné D, Sarr A, Gomez-Chamorro A, Durand J, Cayol C, Rais O, et al. Competition between strains of Borrelia afzelii inside the rodent host and the tick vector. P Roy Soc B-Biol Sci. 2018;285 1890.
  7. Genné D, Sarr A, Rais O, Voordouw MJ. Competition between strains of Borrelia afzelii in immature Ixodes ricinus ticks is not affected by season. Front Cell Infect Microbiol. 2019;9 431.
  8. Voordouw MJ. Co-feeding transmission in Lyme disease pathogens. Parasitology. 2015;142 2:290-302.
  9. Jacquet M, Durand J, Rais O, Voordouw MJ. Strain-specific antibodies reduce co-feeding transmission of the Lyme disease pathogen, Borrelia afzelii. Environ Microbiol. 2016;18 3:833-45.
  10. Belli A, Sarr A, Rais O, Rego ROM, Voordouw MJ. Ticks infected via co-feeding transmission can transmit Lyme borreliosis to vertebrate hosts. Scientific Reports. 2017;7 1:5006.

People

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Maarten, Cindy, and Dolores at the 15th International Congress on Lyme Borreliosis (ICLB15) and Other Tick-Borne Diseases, which was held from 11 to 14 September 2018 at the Centers for Disease Control and Prevention (CDC) at Emory University in Atlanta, Georgia.

Cindy Bregnard (doctoral student)

Cindy Bregnard is doing her PhD under the supervision of Maarten Voordouw. She is currently based at the University of Neuchatel in Neuchatel, Switzerland.

Cindy Bregnard is doing her PhD under the supervision of Maarten Voordouw. She is currently based at the University of Neuchatel in Neuchatel, Switzerland.

Biography of Cindy Bregnard: Cindy Bregnard is a doctoral student who started her PhD in August 2016 at the University of Neuchâtel under the supervision of Dr Maarten Voordouw. This became a long-distance supervisory relationship when Maarten moved to the University of Saskatchewan. While Maarten remains her main PhD thesis supervisor, Dr Jacob Koella is her co-supervisor at the University of Neuchâtel. Cindy did her BSc and MSc in Biology at the University of Neuchâtel. She did her MSc under the supervision of Maarten where she worked on a fungal pathogen, Batrachochytrium dendrobatidis (Bd), which causes an infectious disease named chytridiomycosis in amphibian hosts. Cindy’s salary is funded by the Canton of Neuchâtel and she is responsible for teaching practical classes in histology to medical students and biology students. Cindy’s website at the University of Neuchâtel is as follows: https://www.unine.ch/biologie/home/collaborateurs/laboratoire-decologie-et-evoluti/cindy-bregnard.html

Cindy’s PhD thesis topic: Lyme disease is caused by spirochete bacteria of the Borrelia burgdorferi sensu lato (sl) genospecies complex. In Europe, these tick-borne pathogens are transmitted among vertebrate hosts by the sheep tick (Ixodes ricinus). The purpose of my PhD is to investigate the ecological factors that determine the abundance of I. ricinus ticks and the risk of Lyme disease. I am analyzing a 15-year data set that surveyed the abundance of I. ricinus ticks each month at four different elevations on Chaumont Mountain, in Neuchatel, Switzerland. I have discovered that seed production events by beech trees drive the abundance of I. ricinus nymph 2 years later at our study location. In high years of beech seed production, the abundance of rodents increases the following year, which increases the feeding success of I. ricinus larvae, which moult into nymphs that become active 2 years after the masting event. The effect of tree masting on the abundance of Ixodes ticks was first shown in the USA, but our long-term study is one of the first studies to show this phenomenon for I. ricinus in Europe. We are now testing whether these masting events also influenced the abundance of ticks infected with B. burgdorferi sl, and hence the risk of Lyme disease.

Dolores Genné (doctoral student)

Dolores Genné is doing her PhD under the supervision of Maarten Voordouw. She is currently based at the University of Neuchatel in Neuchatel, Switzerland.

Dolores Genné successfully defended her PhD on 21 August 2020 at the University of Neuchatel in Neuchatel, Switzerland.

Biography of Dolores Genné: Dolores Genné is a doctoral student who started her PhD in September 2016 at the University of Neuchâtel under the supervision of Dr Maarten Voordouw. Dolores successfully defended her PhD on 21 August 2020 at the University of Neuchatel in Neuchatel, Switzerland.

She did her MSc under the supervision of Maarten where she investigated whether competition occurs between strains of Borrelia afzelii in the rodent host and the tick vector. She has continued to study this topic for her PhD thesis (see below). Dolores’s salary is funded by the Canton of Neuchâtel and she is responsible for teaching practical classes in histology to medical students and biology students. Dolores’s website at the University of Neuchâtel is as follows: https://www.unine.ch/biologie/home/collaborateurs/laboratoire-decologie-et-evoluti/dolores-genne-vizcardo.html

Dolores’s PhD thesis topic: 

Genetically variable pathogens often establish multiple-strain infections in the host (also known as mixed infections or co-infections). Co-infections in the host can result in interactions between strains that influence their transmission success and hence the strain composition of the pathogen population. I use the multi-strain tick-borne pathogen Borrelia afzelii as a model system to study how co-infection and competition influence the transmission success of the underlying strains.

I have shown using controlled experiments that co-infections in the rodent host reduce the transmission success of the B. afzelii strains to feeding ticks compared to when they are alone (Genné et al., 2018, Genné et al., 2019). I have shown that co-infection reduces the presence of the two strains in the tissues of the rodent hosts, which subsequently causes the reduced transmission from the co-infected mice to the feeding ticks. I also showed that B. afzelii strains have lower abundance in co-infected ticks compared to when they are alone in the tick (Genné et al., 2018, Genné et al., 2019). I am currently investigating whether co-infection in the tick influences the transmission success of the B. afzelii strains from the infected tick to the naïve host.

 

GENNÉ, D., SARR, A., GOMEZ-CHAMORRO, A., DURAND, J., CAYOL, C., RAIS, O. & VOORDOUW, M. J. 2018. Competition between strains of Borrelia afzelii inside the rodent host and the tick vector. Proceedings of the Royal Society B: Biological Sciences, 285.

GENNÉ, D., SARR, A., RAIS, O. & VOORDOUW, M. J. 2019. Competition between strains of Borrelia afzelii in immature Ixodes ricinus ticks is not affected by season. Frontiers in Cellular and Infection Microbiology, 9.

 

Christopher Zinck (doctoral student)

Chris Zinck is doing his PhD under the supervision of Maarten Voordouw. He is currently based at the University of Saskatchewan in Saskatoon, Canada.

Chris Zinck is doing his PhD under the supervision of Maarten Voordouw at the University of Saskatchewan in Saskatoon, Canada.

Biography of Christopher Zinck: Chris is a doctoral student who started his PhD in May 2019 at the Western College of Veterinary Medicine (WCVM), University of Saskatchewan under the supervision of Dr. Maarten Voordouw. Chris did his BSc and MSc in biology at Mount Allison University, in New Brunswick, Canada. His MSc was supervised by Dr. Vett Lloyd and investigated the infection prevalence of two tick-borne pathogens, Borrelia burgdorferi and Borrelia miyamotoi, in wildlife in Atlantic Canada, with a primary focus on New Brunswick. This research involved the collection of roadkill and other sources of deceased wildlife to assess the spread of Borreliathrough wildlife hosts, as this helps inform the potential for endemic tick populations to be exposed to the pathogens. Chris also worked as a lab technologist under Dr. Vett Lloyd investigating Leptospirosis seropositivity in New Brunswick canines, a project funded by the Public Health Agency of Canada. Chris’s stipend at the WCVM is funded by the Dean’s Scholarship awarded by the College of Graduate and Post-Graduate Studies (CGPS).

Chris’s PhD thesis topic: In North America, Lyme disease is caused by the bacterium Borrelia burgdorferi, which is vectored among vertebrate hosts by the blacklegged tick (Ixodes scapularis). Borrelia burgdorferi consists of many unique strains that vary in their potential infectivity, i.e. their likelihood of being transmitted from a tick to a reservoir, and vice-versa. This project will investigate variation in life history traits among Canadian strains of B. burgdorferi. Life history traits investigated include virulence (i.e. damage done to the host), abundance in host tissues, and host-to-tick transmission. We predict that strains that establish higher abundance in host tissues (especially the skin) will have higher host-to-tick transmission and induce more virulence in their host organism. This project will help our understanding of how natural selection shapes the life history strategy of this important tick-borne pathogen.

 

Alexandra Foley-Eby (doctoral student)

 

Alexandra Foley-Eby is doing her PhD under the supervision of Maarten Voordouw at the University of Saskatchewan in Saskatoon, Canada.

Biography of Alexandra Foley-Eby: Alex is starting her PhD in September 2020 at the Western College of Veterinary Medicine (WCVM), University of Saskatchewan under the supervision of Dr. Maarten Voordouw. Alex attained her Bachelor of Science, with Honours, at Dalhousie University in Halifax, Nova Scotia in 2016. Under the supervision of Dr. Tatiana Rossolimo, her Honours thesis was focussed on the prevalence of Rickettsia spp. and Bartonella spp. bacteria in Ctenocephalides felis (cat fleas) in the Halifax Regional Municipality. From 2016 to 2018 she completed her Master of Science, under the supervision of Dr. Vett Lloyd, at Mount Allison University in Sackville, New Brunswick. Her Masters project studied the infection prevalence of Borrelia burgdorferi in ticks and the seroprevalence of Borrelia exposure in dogs on Prince Edward Island. A summary of the results from Alexandra’s MSc work will be published in the Canadian Veterinary Journal in October 2020. Alex’s stipend at the WCVM is funded by the New Faculty Graduate Student Support Program graduate scholarship that is awarded by the College of Graduate and Post-Graduate Studies (CGPS).

Alex’s PhD thesis topic: To be determined.

Prasobh Raveendran Thampy (technician)

Prasobh Raveendran Thampy is working as a research technician in the Voordouw Tick & Lyme Lab at the University of Saskatchewan in Saskatoon, Canada.

Prasobh Raveendran Thampy is working as a research technician in the Voordouw Tick & Lyme Lab at the University of Saskatchewan in Saskatoon, Canada.

Biography of Prasobh Raveendran Thampy: Prasobh Thampy is a technician from “Gods own country Kerala”, India. He did his Master’s in Bioinformatics at Bharathidasan University, Trichy. Before moving to Saskatoon he worked as Project Trainee at Dr. Manoj’s Lab, Indian Institute of Technology, Madras. Prasobh did another Masters at the University of Saskatchewan with Dr. Jose Andres on genetic architecture of host-related adaptationsin the soapberry bugs. Prasobh started working with Dr. Neil Chilton from 2015 as Research Technician at the Department of Biology, U of S comparing the population genetics of Dermacentor andersoni and D. variabilis across the Canadian prairies. In April 2019, Prasobh started his job as a technician in the Voordouw Tick & Lyme lab.

 

Georgia Hurry (NSERC USRA)

 Georgia Hurry is working as an NSERC undergraduate student research associate (USRA) in the Voordouw Tick & Lyme Lab at the University of Saskatchewan in Saskatoon, Canada.

Georgia Hurry is working as an NSERC undergraduate summer research associate (USRA) in the Voordouw Tick & Lyme Lab at the University of Saskatchewan in Saskatoon, Canada.

Biography of Georgia Hurry: Georgia is an NSERC-USRA student that just completed her BSc in Biology at the University of Saskatchewan. Originally from Summerland, British Columbia, she moved to Saskatoon to play volleyball for the UofS Huskies and pursue her dream of studying veterinary medicine. Her main interests are mammalian anatomy and physiology, as well as parasitology and immunology. For the summer of 2020, she is working in Dr. Maarten Voordouw’s Tick & Lyme lab, helping analyze a data set and prepare a manuscript for publication. This project involves looking at the effects of the Lyme disease pathogen, Borrelia afzelli, on the life history traits of the tick vector.

Courses

Disease Ecology and Epidemiology (VTMC 238.2) to first-year veterinary students.

Publications

For a complete list of publications, please see my site on Google Scholar (https://scholar.google.ch/citations?user=49Ju1HIAAAAJ&hl=en).

 

Most of the pdf files of my publications are currently available on my ResearchGate website (https://www.researchgate.net/profile/Maarten_Voordouw).

PhD and MSc Opportunities

We currently do not have any open positions for graduate students or postdocs. However, anyone interested in doing an MSc, PhD, or postdoc in our lab is welcome to contact me.

 

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