3rd Biennial Maritime Tick and Ticks Vectored
Disease Research Conference:
Ticks and Lyme Disease
April 28, 2018
10:00 am to 3:00 pm
Mount Allison University
Barclay Building Room 02
Disease Research Conference:
Ticks and Lyme Disease
April 28, 2018
10:00 am to 3:00 pm
Mount Allison University
Barclay Building Room 02
Lily Dart, Michael Fox and Pamela Fowler
Citizen Science and Experimental Learning: Tick Education in New Brunswick Provincial Curriculum
The risk of contracting a tick-borne disease is growing in the Maritimes. Currently, New Brunswick does not educate youth about ticks, despite this demographic being at high risk for associated zoonotic diseases. This case study aimed to educate a group of high school students about ticks and tick-borne diseases, and increase interest in science using various pedagogical tools. To evaluate this approach, pre-program, and post-program tests were administered. The tick education program effectively educated the high school students about ticks and tick-borne diseases (p < 0.05), and following the active participation in scientific research, the students were more interested in science and indicated that they were more inclined to study science in post-secondary school (p < 0.05). Due to the success of this program, and the identified need for tick education in the province, the New Brunswick Department of Education and Early Childhood development has endorsed this curriculum and will be distributing it to schools in the coming year.
David Lieske, Vett Lloyd, Mount Allison University
New Brunswick’s Blacklegged Ticks: What We Know About their Current Distribution and a Forecast for the Future
The Blacklegged tick (Ixodes scapularis) is a species that completes its three-stage life cycle by feeding on a range of hosts, including humans. Known to carry the bacterium that causes Lyme disease (Borrelia burgdorferi), blacklegged ticks are currently undergoing northward range expansion in response to climate change. Given the dynamic and changing pattern of tick distribution, and the resulting changes in risk to human health, a detailed understanding of where this disease-causing organism occurs is vital. In order to assess current distributional information for the province of New Brunswick, three years of data on adult ticks, submitted during the springtime to Mount Allison University, were used to construct a species distribution model (SDM). The model focused on the following important broad-scale environmental and climatic factors: forest cover, forest structure (tree height), the presence of rivers and wetlands, mean annual precipitation, and cool temperatures (degree days ˂ 00C). Results showed that blacklegged ticks occur throughout the southern-most portion of the province, in close proximity to coastlines and major waterways, and that milder winter conditions are a strong predictor of tick occurrence. Using two different downscaled climate change projections, based on “stabilized” (RCP 4.5) and “business as usual” (RCP 8.5) carbon emissions scenarios, a very large proportion (roughly a quarter to a third) of the province is expected to be highly suitable for ticks by the 2080s. Comparison of model predictions with the distributional pattern of seropositive dogs indicates that ticks occur beyond the core of their current range. This suggests that long-range dispersal events (e.g., via migrating birds) convey ticks into northern portions of the province in sufficient numbers to infect dogs. We consider the implications of these findings for future surveillance and public communication efforts.
Joseph J. Nocera, University of New Brunswick
Determinants of Dispersal and Movement of Juvenile Moose (Alces alces) Infected with Winter Ticks (Dermacentor albipictus)
Mammals can experience altered movement patterns in stages of heavy infestation of ectoparasites. For instance, raccoon dogs (Nyctereutes procyonoides) heavily infested with ectoparasitic burrowing mites (Sarcoptes scabiei) showed sharp declines in home range size and daily movement length. Similarly wombats (Vombatus ursinus) spent much less time walking than their non-infected counterparts, presumably as an energy-saving strategy. We predict that a similar pattern will be seen in moose (Alces alces) heavily infested with winter ticks (Dermacentor albipictus). If movement is reduced, then this has major implications on their ability to acquire resources. It can cause them to be unable to reach seasonal resources (e.g., wetlands in the summer, uplands in the winter), or can cause them to sequester themselves at feeding sites which increases predation risk; all of which ultimately affects their fitness and survival.
We seek to determine if winter tick burden is extensive enough to cause changes in behavior and movement in moose. If an individual is compromised due to a tick infestation, we predict that its movements will be of shorter length and duration than those of a less infested individual. To test this, we have been monitoring tick load, survival, and movement patterns of moose through capture and deployment of GPS collars in New Brunswick. Moose capture has focussed on calves (as they are the most likely to show adverse health effects from environmental stressors). For each captured animal we conducted a tick survey, and outfit the animal with a GPS collar.
We will statistically examine such features of their movement as: path tortuosity, space use, home range, and gap crossing. To do so, we will test the prediction that path tortuosity will decrease in heavily infested animals (i.e., their paths will become more linear). Space use and home range size will be smaller in heavily infested animals. Lastly, because gap crossing can be risky (e.g., increased predation), we will test the prediction that heavily infested animals will cross fewer (and smaller) gaps.
N Faraone, NK Hillier, Biology Department, Acadia University, Wolfville (NS)
Olfactory basis of tick behavior and novel repellent development
The blacklegged tick (Ixodes scapularis) is the main vector of Borrelia burgdorferi, the etiological agent of Lyme disease. In Atlantic Canada, the spread of I. scapularis ticks and the high incidence of Lyme disease cases reported in recent years have raised concerns for public health. The threat of disease transmission has resulted in an increasing demand for effective, safe and environmentally-friendly repellent products. Plant-derived essential oils are natural products that exhibit insecticidal and repellant activities and represent a promising alternative to synthetic repellants. Preliminary bioassays suggest that certain essential oils (i.e. lemongrass) have shown potential in repelling I. scapularis. However, the mechanism by which ticks detect odor stimuli and how these stimuli are perceived as repellents is not completely understood, and this knowledge results critical for better selecting the appropriate chemicals and developing suitable formulations for protecting people against tick bites. Moreover, it is not clear if the presence of the bacterial infection may alter the response of ticks to odor stimuli. In this project, we want to explore tick response to stimulation with selected essential oils and their main components, comparing the responses to those of infected ticks, and using this information to develop new repellent products for personal protection.
Andrea Kirby, Vett Lloyd, Mount Allison University
Ticks in the Maritimes
Lyme disease is caused by the spirochete Borrelia sp. bacteria of the Lyme borreliosis group and is the most common vector borne disease in temperate regions of the world, including Canada. The main vector of this bacterium in the Maritimes is the Ixodes scapularis tick. The Tick Bank was created at Mount Allison University in 2012 to collect, document and test ticks collected by passive surveillance. Ticks are submitted by veterinary clinics and the general public, they are then identified, documented and tested for Borrelia sp. Testing was done using nested polymerase chain reaction and only ticks with amplification of two genes, outer surface protein A and flagellin B, were considered to be true positives. My research began in 2016 with analysis of 1052 ticks and ended in 2017 with 1380 ticks submitted and tested. A number of different species of ticks and ticks from 6 other provinces and 2 countries other than Canada were submitted. For New Brunswick 686 and 856 I. scapularis were submitted in 2016 and 2017, respectively. The province wide infection was 11% for 2016 and 10% for 2017 for New Brunswick. For Nova Scotia the infection incidence was calculated to be 24% over the two years. Continued analysis of ticks from the Maritimes will allow ongoing monitoring of tick and Borrelia distribution.
T. Caddell, A.El Nabbout, J. Kho, E. MacNutt-Burrows, Khadijah Carey, J. Piche, T. Rossoloimo. Dalhousie University
Update on the bacteria prevalence of I. scapularis and D. variabilis in Nova Scotia
Ticks are prominent reservoirs of bacterial agents including Lyme disease and Rocky Mountain spotted fever. However, the infection prevalence is not always constant and can vary from year to year or season to season. It is therefore important to conduct overall surveys on the prevalence of potential pathogenic bacteria in local ticks. In this ongoing study, we test local tick species commonly found in Nova Scotia, Ixodes scapularis and Dermacentor variabilis, for potentially pathogenic bacteria that these species are known to carry such as Borrelia burgdorferi and Rickettsia spp.. Genus or species specific primers and standard Polymerase Chain Reaction (PCR) were used to determine infection prevalence of sampled ticks. In this presentation, we will look at current results and how it compares to those from past years in order to examine the stability of bacteria infection in ticks of Nova Scotia. This study will surely provide a much needed broad-scale analysis on the under-studied ticks of Nova Scotia.
M. Curry, M. Rooney, M. Mitton, H. Johnston, J. Kho, H. Sleiman, T. Rossolimo Dalhousie University
Identification of ticks using morphological features.
With the advent of global warming, tick species are starting to be found outside of their previously recorded ranges. Recent studies have suggested that new morphs and hybrids of ticks have been emerging worldwide including in the East coast of Canada. This has led to difficulty in correctly identifying local ticks among other things. In this presentation, we will go over morphological features that can be used to identify tick species and possibly morphs/hybrids. While not a comprehensive lecture on taxonomy, we hope to improve scientists’ and the public’s skill in recognizing ticks, with minimal scientific equipment.
Douglas Munn[i], Jackie Badcock[ii], Robbin Lindsay[iii], and Joseph J. Nocerai[i]
Assessing blacklegged tick (Ixodes scapularis) range expansion in New Brunswick, Canada
Blacklegged ticks (Ixodes scapularis) are the primary vector of several infectious diseases in eastern North America, including Lyme Disease, Human Granulocytic Anaplasmosis (HGA), and Babesiosis, each of which can prove fatal if left untreated. The ticks were first detected in New Brunswick (NB) in 2008. Annual tick surveillance in NB has led to the discovery of breeding populations in five counties (Charlotte, Kings, Saint John, and most recently, Albert and Westmorland). Previous research suggests blacklegged tick breeding-population presence is limited by degree days (DD), which are a proxy for the number of days in a year above 0° Celsius. Areas with <2800DD are unable to harbor breeding populations of blacklegged ticks. Research also suggests that blacklegged tick densities and infection probabilities are a function of forest fragmentation. Increased patch isolation corresponds to greater infection probability, while decreased patch size corresponds to greater tick densities. Therefore, we will test these hypotheses on New Brunswick’s blacklegged tick populations. Sample sites are surveilled by dragging 1m2 fabric sheets along 2 km of sampling transects, at a rate of 3 hours per site. Each blacklegged tick specimen is tested for the suite of infectious bacteria using polymerase chain reaction methodology (PCR) at the Public Health Agency of Canada (PHAC) National Microbiology Laboratory. However, these measurements only predict an area’s habitability by breeding populations of blacklegged ticks. Their range expansion is NB is likely a function of more than these abiotic ecological predictors. Migratory birds are a major long-range transporter of blacklegged ticks, and are a significant factor in the tick’s range expansion. Comparatively little is known about localized range expansion and intermediary hosts. As such, we are examining the role of two non-migratory birds, Ruffed Grouse (Bonasa umbellus) and Spruce Grouse (Falcipennis canadensis), as potential intermediary vectors that influence local distribution of black-legged ticks in NB. To determine this, we are examining the rate of exposure to B. burgdorferi (and other spirochetes) in grouse, which we accomplish by testing for antibodies in the hearts of harvested birds. We expect that our sampling will detect presence of Borrelia spp. carrying blacklegged ticks in areas not yet discovered, as well as improve our understanding of their movement and localized range expansion.
[i] University of New Brunswick
[ii] NB Department of Health
[iii] Public Health Agency of Canada
Julie Lewis, Vett Lloyd, Mount Allison University
Identification of Borrelia bissettii in ticks from New Brunswick, Canada
Lyme disease is a tick-borne disease that is emerging in Canada. The disease is caused by spirochetes of the Borrelia burgdorferi sensu lato complex, which is expanding as new species are discovered. In Canada, Lyme disease risk has so far been assessed only by detection of Borrelia burgdorferi sensu stricto. From ticks collected between 2014-2016 in New Brunswick, Canada, 7 were shown to be infected with B. bissettii by nested PCR and sequencing of 5 Borrelia bissettii genes. As different Borrelia genospecies are associated with different clinical manifestations and are not detected with the same diagnostic tests, the identification of a previously undocumented or underreported pathogenic Borrelia species has important implications for public and veterinary medicine.
Alexandra Foley-Eby, Vett Lloyd, Mount Allison University
Lyme disease on PEI: estimating human risk using dogs as a sentinel species
Lyme disease, a spirochetosis caused by Borrelia burgdorferi and related bacteria, is the most commonly reported vector borne disease in North America. In 2016 there were 987 reported cases of Lyme in Canada. The first isolation of B. burgdorferi in Atlantic Canada was from in Prince Edward Island in 1992. Over the past 26 years there has been limited research on the state of Lyme on PEI, an Island with comparable climate to endemic and high risk areas in adjacent provinces, as well as several known reservoir species. Ixodes scapularis, one of the two tick vectors of B. burgdorferi in Canada has been reported on the Island since 1989. Despite this, between 2009-2015 there was only a single reported case of Lyme disease on Prince Edward Island. This study took a two-part approach at examining the risk of Lyme to Islanders, passive surveillance of Island ticks, and determining canine seroprevalence. Over a period of 15 months, 445 ticks were collected from 11 PEI veterinary clinics. Of these samples, 368 (83%) were found to have likely originated from the Island, 360 (98%) of which were identified as I. scapularis,. Using nested PCR to amplify the B. burgdorferi OspA and FlaB genes, 10.28% of tested ticks were found to carry B. burgdorferi. Over the course of this study, 199 canine serum samples were tested with C6 ELISA and immunoblot assays. Canine Borrelia seroprevalence was estimated at 3%. While canine Lyme incidence will clearly be higher than human disease incidence due to increased tick exposure of dogs versus humans, the presence of both Borrelia-infected ticks and canine Borrelia seropositive dogs does suggests the likelihood of undiagnosed human Lyme disease on Prince Edward Island.
Chris Zinck, Vett Lloyd, Mount Allison University
Borrelia infection and Presence in New Brunswick Wildlife
Borrelia burgdorferi, the causative agent of Lyme disease, and Borrelia miyamotoi, are zoonotic bacteria that pose significant health risks to humans and companion animals. To assess the risks of these bacteria wild animal tissue samples were collected and tested via PCR in 2016 and 2017. The levels of infection found in the wild, as well as the animals most commonly found infected, allow for predictions to be made on areas of risk for human infection. Further, by determining what tissues and organs carry the bacteria in the infected animals the spread of these Borrelia species can be assessed through the host and the ecosystem.
Louise Billings, Vett Lloyd,
Experiences of Lyme patients in New Brunswick
The complexities of diagnosis and the lived experiences of Lyme patients in New Brunswick will be discussed.
Laurabeth Gill, Vett Lloyd, Mount Allison University
Dichloroacetate- A novel antimicrobial active against Borrelia burgdorferi
Background: Lyme disease is a bacterial infection spread to humans and other mammals through tick bites, which can have serious health effects if left untreated. It is caused by spirochetal bacterial in the Lyme borreliosis family, which includes Borrelia burgdorferi, an increasingly significant pathogen in North America. Dichloroacetate (DCA) is a pyruvate analogue that has been used with some success to treat certain types of cancers by inhibiting the enzyme pyruvate dehydrogenase kinase.
Methods: Borrelia burgdorferi, strain B31 were exposed in vitro to concentrations of DCA within clinical dose guidelines.
Results: Exposed Borrelia burgdorferi, decreased in live cell count in a manner corresponding to increased concentration of DCA, and exhibited alternate morphologies suggesting bacterial metabolic stress. DCA demonstrated no effect on E.coli grown aerobically, but had an effect on E.coli grown anaerobically. Borrelia burgdorferi, strain B31 was also treated in vitro with doxycycline and subsequently treated with DCA, and the combination appeared to have an effect greater than antibiotic monotherapy.
Discussion: The data indicates that DCA has an adverse affect on Borrelia B31 metabolism and growth in vitro. Transcriptomic and proteomic analysis is underway to determine the mode of action of DCA on B. burgdorferi B31 cells.
Joseph Beaton, Vett Lloyd, Mount Allison University
Sex in the Lymelight - Investigating contact transmission of Lyme disease
Background: The causative agent of Lyme disease, Borrelia burgdorferi, is a bacterium in the Spirochaete phylum. Unlike most other Spirochaete bacteria, B. burgdorferi it is not known to transmit between hosts directly but rather utilizes a tick vector in its life cycle. Studies have shown that the spirochete can infect a mammalian host via oral inoculation, and viable B. burgdorferi is present in the urine of wildlife and agricultural animals. In humans, viable B. burgdorferi has been reported in vaginal and seminal fluids. These findings have led us to investigate the possibility of host-host transmission (contact transmission) between mammals in the absence of a tick vector, using a murine animal model.
Methods: Contact transmission was investigated in the context of sexual and nonsexual contact using mice. C3H/HenCrl and BALB/cAnNCrl mice were inoculated with 106 first-passage B31 B. burgdorferi spirochetes by subcutaneous injection and housed individually for a 10-day incubation period. Each infected mouse was then housed with a non-infected partner for three weeks. Each mouse was sacrificed and sample tissue collected at the time of euthanization for Borrelia-specific culturing, direct PCR testing, and for immunostaining and FISH molecular beacon staining.
Results: Results to date have defined the optimal mouse strain, infection route, and infection dosage leading the way to the test of contact transmission. The results for contact transmission are pending and will be presented at the conference.
Discussion: Understanding the potential for contact transmission between mice is important in estimating the rate, season and mode of Borrelia transmission in reservoir hosts. Although the results may be ecologically relevant only in socially grooming animals, so not translatable to humans, it may still be important to consider non-tick-vectored transmission to those working with bodily fluids of infected humans or animals.
Md. Hasibul Haque, Vett Lloyd, Mount Allison University
Molecular detection of Borrelia in human tissue
Background: Lyme borreliosis, commonly known as Lyme disease, is a complex multi-organ disease resulting from infection by the spirochete, Borrelia burgdorferi, and related species. If untreated, the Borrelia bacteria disseminate throughout the body causing debilitating as well as potentially fatal damage to nerve tracts, glia, connective tissues, the joints, the circulatory system and other vital organs, which can cause cardiac, neurological and musculoskeletal symptoms. Conventional testing for Lyme disease relies on assessing the exposure risk to ticks, the disease vector, as well as indirect serological detection of anti-Borrelia antibodies. In some circumstances, direct molecular detection can be a powerful tool for the detection of infection and can provide valuable new information about disease. Here we report a case study involving molecular analysis of autopsy tissues by nested PCR and fluorescent in situ hybridization (FISH) with a molecular beacon probe.
Methods: Upon the death of the patient, the family can request an autopsy and post-mortem analysis of tissue samples. The samples used here were submitted for testing by a pathologist at the request of the donor family. Information on tick exposure and disease was completed through a standard survey form. The pathologist was sent the lab protocol outlining tissues useful for detection of Borrelia and preservation requirements for molecular analysis. In this instance, we received ethanol-submerged tissues and paraffin embedded tissues from a variety of organs. Upon receipt of samples, DNA was extracted from the ethanol-submerged tissues. Tissue DNA samples were then tested for the presence of B. burgdorferi using nested PCR (nPCR) for three Borrelia genes, OspA, FlaB and 23S. Paraffin embedded tissues were used for FlaB molecular beacon FISH.
Results: The patient, a 70 years male Caucasian, lived in a tick endemic region, had a history of multiple tick bites, positive Canadian two-tier serology and symptoms consistent with Lyme disease, all factors which presumably lead to his diagnosis of Lyme disease. A short course of oral antibiotic treatment was conducted. The patient also had a history of coronary artery disease and extensive atherosclerosis, which were the direct cause of his death. Upon hospitalization for these and other conditions intravenous antibiotic therapy was initiated but the patient died before it was completed. Sample tissues from a variety of organs and tissues were tested. Samples from pericardium, endocardium aortic valve, aorta, liver, pancreas and cerebral cortex were found positive by nPCR. FISH further confirmed the presence of FlaB Borrelia DNA in the endocardium sample.
Discussion: These results highlight the value of direct molecular detection of Borrelia in human tissues. In this case, the molecular findings are completely consistent with tick exposure and serology. In other cases, however, this information may not be known and molecular detection offers the possibility of determining if Borrelia is present. Additionally, this approach offers the opportunity to address other research questions such as Borrelia tissue distribution and correlation with tissue damage.
Samantha MacPherson, Nicoletta Faraone, Neil Kirk Hillier
Biology Department, Acadia University, Wolfville (NS), Canada
Behavioural Investigation of Tick (Ixodes scapularis) Response to Essential Oil Compounds for the Development of New Repellant Products
The incidence of Lyme disease in Canada continues to increase as its primary vector, the blacklegged tick (Ixodes scapularis), maintains a growing population. The public has raised the need for safe and natural repellant products to be used in protection against harmful ticks. In this study, the repellency of two essential oil components (EO-A and EO-B) was investigated against I. scapularis nymphs using a horizontal filter paper bioassay. It was found that both EO-A and EO-B exhibit significant repellence against I. scapularis nymphs. These results will contribute to the development of EO-A and/or EO-B containing products in natural product-based tick repellant formulas for personal protection which ultimately aid in helping to prevent the spread of Lyme diseases through a bite from infected ticks.
1) Public Health Agency of Canada. https://www.canada.ca/en/public-health/services/diseases/lyme-disease/surveillance-lyme-disease.html.
2) Ogden, N.H., et al., 2008. Risk maps for range expansion of the Lyme disease vector, Ixodes scapularis, in Canada now and with climate change. BioMed Central 7(1): 24.
Jonathan Bradet-Legris and Isaiah Bishop
Modelling the effects of environmental conditions on the spread of Lyme disease in ticks and reservoir species
A simple interactive animation demonstrating how milder environmental conditions can lead to increases in established tick populations and lyme disease prevalence.