Papers by Catherine Bouchard
Pathogens
Lyme disease (LD) is a tick-borne disease which has been emerging in temperate areas in North Ame... more Lyme disease (LD) is a tick-borne disease which has been emerging in temperate areas in North America, Europe, and Asia. In Quebec, Canada, the number of human LD cases is increasing rapidly and thus surveillance of LD risk is a public health priority. In this study, we aimed to evaluate the ability of active sentinel surveillance to track spatiotemporal trends in LD risk. Using drag flannel data from 2015–2019, we calculated density of nymphal ticks (DON), an index of enzootic hazard, across the study region (southern Quebec). A Poisson regression model was used to explore the association between the enzootic hazard and LD risk (annual number of human cases) at the municipal level. Predictions from models were able to track both spatial and interannual variation in risk. Furthermore, a risk map produced by using model predictions closely matched the official risk map published by provincial public health authorities, which requires the use of complex criteria-based risk assessment....
PLOS ONE, 2022
The incidence of Lyme disease is increasing in Québec and is closely linked to the distribution o... more The incidence of Lyme disease is increasing in Québec and is closely linked to the distribution ofIxodes scapularisticks. A time-to-establishment model developed in 2012 by Leighton and colleagues predicted the year of tick population establishment for each municipality in eastern Canada. To validate if this model correctly predicted tick distribution in Québec, predicted tick establishment was compared to field data from active tick surveillance (2010–2018) using two criteria: i) the detection of at least one tick and ii) the detection of the three questing stages of the tick. The speed of tick establishment and the increase in the exposed human population by 2100 were predicted with the time-to-establishment model. Field observations were consistent with model predictions. Ticks were detected on average 3 years after the predicted year. The probability of tick detection is significantly higher after the predicted year than before (61% vs 27% of collections). The trend was similar ...
The Canadian veterinary journal. La revue vétérinaire canadienne, 2015
There is an increasing risk of Lyme disease in Canada due to range expansion of the tick vector, ... more There is an increasing risk of Lyme disease in Canada due to range expansion of the tick vector, Ixodes scapularis. The objectives of this article are to i) raise public awareness with the help of veterinarians on the emerging and expanding risk of Lyme disease across Canada, ii) review the key clinical features of Lyme disease in dogs, and iii) provide recommendations for veterinarians on the management of Lyme disease in dogs.
Canadian Journal of Public Health
Objective In 2021, a first outbreak of anaplasmosis occurred in animals and humans in southern Qu... more Objective In 2021, a first outbreak of anaplasmosis occurred in animals and humans in southern Québec, with 64% of confirmed human cases located in Bromont municipality. Ixodes scapularis ticks and Peromyscus mouse ear biopsies collected in Bromont from 2019 to 2021 were analyzed for Anaplasma phagocytophilum (Ap) with the objective of determining whether an early environmental signal could have been detected before the outbreak. Methods Samples were collected for a concurrent study aiming to reduce Lyme disease risk. Between 2019 and 2021, up to 14 experimental sites were sampled for ticks and capture of small mammals took place on three sites in 2021. Samples were screened for Ap using multiplex real-time PCR, and genetic strains were identified using a single-nucleotide polymorphism assay. Results Analyses showed an increase of 5.7% in Ap prevalence in ticks (CI95: 1.5–9.9) between 2019 and 2020, i.e., one year before the outbreak. A majority of Ap-positive ticks were infected wi...
Frontiers in Public Health
ObjectivesWith vector-borne diseases emerging across the globe, precipitated by climate change an... more ObjectivesWith vector-borne diseases emerging across the globe, precipitated by climate change and other anthropogenic changes, it is critical for public health authorities to have well-designed surveillance strategies in place. Sentinel surveillance has been proposed as a cost-effective approach to surveillance in this context. However, spatial design of sentinel surveillance system has important impacts on surveillance outcomes, and careful selection of sentinel unit locations is therefore an essential component of planning.MethodsA review of the available literature, based on the realist approach, was used to identify key decision issues for sentinel surveillance planning. Outcomes of the review were used to develop a decision tool, which was subsequently validated by experts in the field.ResultsThe resulting decision tool provides a list of criteria which can be used to select sentinel unit locations. We illustrate its application using the case example of designing a national s...
Theoretical landscapes;Allee effect;Input parameters;Calibration analysis;Sensitivity analysis
Additional file 1. Questionnaire.pdf. Questionnaire on Individual Adaptation to Lyme Disease. Des... more Additional file 1. Questionnaire.pdf. Questionnaire on Individual Adaptation to Lyme Disease. Description of data: English language version of the questionnaire developed and used for this study.
l'utilisation des cerfs à titre de sentinelles pour le vecteur et les agents pathogènes. D'après ... more l'utilisation des cerfs à titre de sentinelles pour le vecteur et les agents pathogènes. D'après nos résultats, bien qu'ils soient des sentinelles efficaces pour détecter Anaplasma phagocytophilum, les cerfs semblent des sentinelles inefficaces pour détecter les zones d'établissement du complexe I. scapularis-B. burgdorferi. Enfin, une analyse de l'impact de la diversité des hôtes et de l'habitat sur l'abondance de la tique I. scapularis et la prévalence de B. burgdorferi a été effectuée et ce, en tenant compte d'autres facteurs environnementaux. Ces analyses ont permis de déterminer les facteurs critiques pour l'établissement du complexe I. scapularis-B. burgdorferi et d'explorer la contribution relative de diverses espèces d'hôtes. D'après nos études, la diversité de la communauté d'hôte et la diversité de l'habitat influencent le complexe I. scapularis-B. burgdorferi. De plus, le climat (la température et les précipitations) joue un rôle significatif dans l'établissement, la survie et le développement des populations d'I. scapularis. Ce projet de recherche a permis d'explorer et d'identifier divers facteurs environnementaux biotiques et abiotiques influençant l'établissement du complexe I. scapularis-B. burgdorferi dans le Sud-Ouest du Québec. Ceux-ci pourraient être utilisés à titre d'indicateurs environnementaux du risque de la maladie de Lyme au Québec et possiblement ailleurs au Canada.
Remote Sensing, 2021
Climate change is facilitating the geographic range expansion of populations of the tick vector o... more Climate change is facilitating the geographic range expansion of populations of the tick vector of Lyme disease Ixodes scapularis in Canada. Here, we characterize and map the spatio-temporal variability of environments suitable for I. scapularis using Earth observation (EO) data. A simple algorithm for I. scapularis occurrence (cumulative degree-days and forest: CSDF) was developed by combining cumulative annual surface degree-days above 0 °C and forest cover. To map the environmental risk of I. scapularis (risk of I. scapularis: RIS) in central and eastern Canada from 2000 to 2015, CSDF was adjusted using data from an I. scapularis population model. CSDF was validated using cumulative annual degree days >0 °C (CADD) from meteorological stations, and CSDF was strongly associated with CADD (n = 52, R2 > 0.86, p < 0.001). Data on field surveillance for I. scapularis ticks (2008 to 2018) were used to validate the risk maps. The presence of I. scapularis ticks was significantly...
Canada Communicable Disease Report, 2020
Background: Lyme disease is an emerging vector-borne zoonotic disease of increasing public health... more Background: Lyme disease is an emerging vector-borne zoonotic disease of increasing public health importance in Canada. As part of its mandate, the Canadian Lyme Disease Research Network (CLyDRN) launched a pan-Canadian sentinel surveillance initiative, the Canadian Lyme Sentinel Network (CaLSeN), in 2019. Objectives: To create a standardized, national sentinel surveillance network providing a real-time portrait of the evolving environmental risk of Lyme disease in each province. Methods: A multicriteria decision analysis (MCDA) approach was used in the selection of sentinel regions. Within each sentinel region, a systematic drag sampling protocol was performed in selected sampling sites. Ticks collected during these active surveillance visits were identified to species, and Ixodes spp. ticks were tested for infection with Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, Babesia microti and Powassan virus Results: In 2019, a total of 567 Ixodes spp. ticks (I. scapularis [n=550]; I. pacificus [n=10]; and I. angustus [n=7]) were collected in seven provinces:
Ticks and Tick-borne Diseases, 2021
The tick vector of Lyme disease, Ixodes scapularis, is currently expanding its geographical distr... more The tick vector of Lyme disease, Ixodes scapularis, is currently expanding its geographical distribution northward into southern Canada driving emergence of Lyme disease in the region. Despite large-scale studies that attributed different factors such as climate change and changes in land use to the geographical expansion of the tick, a comprehensive understanding of local patterns of tick abundance is still lacking in that region. Using a newly endemic periurban nature park located in Quebec (Canada) as a model, we explored intra-habitat patterns in tick distribution and their relationship with biotic and abiotic factors. We verified the hypotheses that (1) there is spatial heterogeneity in tick densities at the scale of the park and (2) these patterns can be explained by host availability, habitat characteristics and microclimatic conditions. During tick activity season in three consecutive years, tick, deer, rodent and bird abundance, as well as habitat characteristics and microclimatic conditions, were estimated at thirty-two sites. Patterns of tick distribution and abundance were investigated by spatial analysis. Generalised additive mixed models were constructed for each developmental stage of the tick and the relative importance of significant drivers on tick abundance were derived from final models. We found fine-scale spatial heterogeneity in densities of all tick stages across the park, with interannual variability in the location of hotspots. For all stages, the local density was related to the density of the previous stage in the previous season, in keeping with the tick's life cycle. Adult tick density was highest where drainage was moderate (neither waterlogged nor dry). Microclimatic conditions influenced the densities of immature ticks, through the effects of weather at the time of tick sampling (ambient temperature and relative humidity) and of the seasonal microclimate at the site level (degree-days and number of tick adverse moisture events). Seasonal phenology patterns were generally consistent with expected curves for the region, with exceptions in some years that may be attributable to founder events. This study highlights fine scale patterns of tick population dynamics thus providing fundamental knowledge in Lyme disease ecology and information applicable to the development of well-targeted prevention and control strategies for public natural areas affected by this growing problem in southern Canada.
BMC Public Health, 2020
Background Recent evidence suggests that climate change and other factors are leading to the emer... more Background Recent evidence suggests that climate change and other factors are leading to the emergence of Lyme disease in the province of Quebec, where it previously did not exist. As risk areas expand further north, the population can adopt specific preventive behaviors to limit chances of infection. The objectives of this study were to (1) create an index of Lyme disease prevention behaviors (LDPB), and (2) use the theory of planned behavior (TPB) to explain the decision-making process of people who choose to adopt LDPB. Methods A sample of 1959 adults living in a Lyme disease risk area completed a questionnaire by phone (n = 1003) or on the Web (n = 956). The questionnaire measured whether they did or did not adopt the LDPB proposed by public health officials. It also measured some TPB variables, including their attitude or perceived social norms regarding LDPB. Results Our findings led to the creation of a Lyme disease prevention index consisting of 10 behaviors, down from the 1...
BMC Medical Research Methodology, 2020
Background To monitor the adoption of climate change adaptive behaviors in the population, public... more Background To monitor the adoption of climate change adaptive behaviors in the population, public health authorities have to conduct national surveys, which can help them target vulnerable subpopulations. To ensure reliable estimates of the adoption of these preventive behaviors, many data collection methods are offered by polling firms. The aim of this study was to compare a telephone survey with a web survey on Lyme disease with regard to their representativeness. Methods The data comes from a cross-sectional study conducted in the Province of Québec (Canada). In total, 1003 people completed the questionnaire by telephone and 956 filled in a web questionnaire. We compared the data obtained from both survey modes with the census data in regard to various demographic characteristics. We then compared the data from both samples in terms of self-reported Lyme disease preventive behaviors and other theoretically associated constructs. We also assessed the measurement invariance (equiva...
Parasites & Vectors, 2020
Background Lyme disease (LD) is an increasing public health threat in temperate zones of the nort... more Background Lyme disease (LD) is an increasing public health threat in temperate zones of the northern hemisphere, yet relatively few methods exist for reducing LD risk in endemic areas. Disrupting the LD transmission cycle in nature is a promising avenue for risk reduction. This experimental study evaluated the efficacy of fluralaner, a recent oral acaricide with a long duration of effect in dogs, for killing Ixodes scapularis ticks in Peromyscus maniculatus mice, a known wildlife reservoir for Borrelia burgdorferi in nature. Methods We assigned 87 mice to 3 fluralaner treatment groups (50 mg/kg, 12.5 mg/kg and untreated control) administered as a single oral treatment. Mice were then infested with 20 Ixodes scapularis larvae at 2, 28 and 45 days post-treatment and we measured efficacy as the proportion of infesting larvae that died within 48 h. At each infestation, blood from 3 mice in each treatment group was tested to obtain fluralaner plasma concentrations (Cp). Results Treatmen...
Frontiers in Veterinary Science, 2019
International Journal of Environmental Research and Public Health, 2019
The aim of this study is to document climate change adaptation interventions targeting Lyme disea... more The aim of this study is to document climate change adaptation interventions targeting Lyme disease at the municipal level in the province of Quebec (Canada). This exploratory study relies on the theory of planned behavior and certain constructs from the health belief model to identify the factors leading municipal authorities to implement preventive interventions for Lyme disease (PILD). Data were obtained from an online survey sent, during the summer of 2018, to municipal officers in 820 municipalities in Quebec, in all health regions where the population is at risk of contracting Lyme disease (response rate = 36%). The questionnaire was used to measure the implementation of PILD, the intention to implement these interventions, attitudes, perceived social pressure, perceived control (levers and barriers) over interventions, perceived effectiveness of preventive measures, risk, and perceived vulnerability. Results of structural equation analyses showed that attitudes were significa...
Environmental Health Perspectives, 2018
BACKGROUND: The risk of contracting Lyme disease (LD) can vary spatially because of spatial heter... more BACKGROUND: The risk of contracting Lyme disease (LD) can vary spatially because of spatial heterogeneity in risk factors such as social-behavior and exposure to ecological risk factors. Integrating these risk factors to inform decision-making should therefore increase the effectiveness of mitigation interventions. OBJECTIVES: The objective of this study was to develop an integrated social-behavioral and ecological risk-mapping approach to identify priority areas for LD interventions. METHODS: The study was conducted in the Montérégie region of Southern Quebec, Canada, where LD is a newly endemic disease. Spatial variation in LD knowledge, risk perceptions, and behaviors in the population were measured using web survey data collected in 2012. These data were used as a proxy for the social-behavioral component of risk. Tick vector population densities were measured in the environment during field surveillance from 2007 to 2012 to provide an index of the ecological component of risk. Social-behavioral and ecological components of risk were combined with human population density to create integrated risk maps. Map predictions were validated by testing the association between high-risk areas and the current spatial distribution of human LD cases. RESULTS: Social-behavioral and ecological components of LD risk had markedly different distributions within the study region, suggesting that both factors should be considered for locally adapted interventions. The occurrence of human LD cases in a municipality was positively associated with tick density (p < 0:01) but was not significantly associated with social-behavioral risk. CONCLUSION: This study is an applied demonstration of how integrated social-behavioral and ecological risk maps can be created to assist decisionmaking. Social survey data are a valuable but underutilized source of information for understanding regional variation in LD exposure, and integrating this information into risk maps provides a novel approach for prioritizing and adapting interventions to the local characteristics of target populations.
PLOS ONE, 2018
Climate change is driving emergence and establishment of Ixodes scapularis, the main vector of Ly... more Climate change is driving emergence and establishment of Ixodes scapularis, the main vector of Lyme disease in Québec, Canada. As for the black-legged tick, I. scapularis Say, global warming may also favor northward expansion of other species of medically important ticks. The aims of this study were to determine (1) current diversity and abundance of ticks of public health significance other than I. scapularis, (2) sex and age of the human population bitten by these ticks (3), and the seasonal and geographic pattern of their occurrence. From 2007 to 2015, twelve tick species other than I. scapularis were submitted in the Québec passive tick surveillance program. Of these 9243 ticks, 91.2% were Ixodes cookei, 4.1% were Dermacentor variabilis, 4.0% were Rhipicephalus sanguineus and 0.7% were Amblyomma americanum. The combined annual proportion of submitted I. cookei, D. variabilis, R. sanguineus and A. americanum ticks in passive surveillance rose from 6.1% in 2007 to 16.0% in 2015 and an annual growing trend was observed for each tick species. The number of municipalities where I. cookei ticks were acquired rose from 104 to 197 during the same period. Of the 862 people bitten by these ticks, 43.3% were I. cookei ticks removed from children aged < 10 years. These findings demonstrate the need for surveillance of all the tick species of medical importance in Québec, particularly because climate may increase their abundance and geographic ranges, increasing the risk to the public of the diseases they transmit.
Ticks and Tick-borne Diseases, 2016
Lyme disease (LD) is emerging in Canada. A key preventive strategy is promoting the adoption by t... more Lyme disease (LD) is emerging in Canada. A key preventive strategy is promoting the adoption by the general public of personal preventive behaviors regarding tick bites. The aim of this study was to measure the changes in public awareness toward ticks and LD before and after the launch of a national communication campaign in Canada using data from two surveys conducted in March and December 2014. The results show a significant increase in awareness of LD after compared to before the campaign, but also suggest that the importance of this increase is not equal amongst Canadian regions. Moreover, respondents whose level of awareness increased most significantly were those who lived in regions with low entomologic risk. The findings underline the importance of risk communications for emerging diseases and reinforce the need to understand the specific characteristics of the targeted populations before the implementation of communication campaigns to increase their efficacy.
Journal of Medical Entomology, 2013
Due to recent establishment of the blacklegged tick, Ixodes scapularis Say, in southeastern Canad... more Due to recent establishment of the blacklegged tick, Ixodes scapularis Say, in southeastern Canada, tick-borne zoonoses (Lyme disease, human granulocytotropic anaplasmosis, and babesiosis) are of growing concern for public health. Using white-tailed deer (Odocoileus virginianus) culled in southwestern Quebec during 2007Ð2008, we investigated whether hunter-killed deer could act as sentinels for early establishing tick populations and for tick-borne pathogens. Accounting for environmental characteristics of culling sites, and age and sex of deer, we investigated whether their tick infestation levels could identify locations of known tick populations detected in active surveillance, presumed tick populations detected by passive surveillance, or both. We also used spatial cluster analyses to identify spatial patterns of tick infestation and occurrence of tick-borne zoonoses infection in ticks collected from the deer. Adult ticks were found on 15% of the 583 deer examined. Adult male deer had the greatest number (Ϸ90%) of adult ticks. Overall, 3, 15, and 0% of the ticks collected were polymerase chain reaction (PCR)-positive for Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti, respectively. Our statistical analyses suggest that sex and age of deer, temperature, precipitation, and an index of tick dispersion by migratory birds were signiÞcantly associated with tick infestation levels. Cluster analysis identiÞed signiÞcant clusters of deer carrying ticks PCR-positive for A. phagocytophilum, and for deer carrying two or more I. scapularis. Our study suggests that hunterkilled deer may be effective as sentinels for emerging areas of tick-borne anaplasmosis. They may have limited use as sentinels for early emerging I. scapularis tick populations and emerging Lyme disease risk. KEY WORDS Ixodes scapularis, Anaplasma phagocytophilum, Borrelia burgdorferi, white-tailed deer, environmental factor The blacklegged tick, Ixodes scapularis Say, is the vector of several tick-borne zoonoses, including Borrelia burgdorferi sensu stricto (Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner); Anaplasma phagocytophilum Dumler, Barbet, Bekker, Dasch, Palmer, Rikihisa & Rurangirwa; and Babesia microti Franca that cause Lyme disease, human granu-locytotropic anaplasmosis, and human babesiosis, respectively (Thompson et al. 2001). I. scapularis ticks are expanding their geographic range northward into southeastern and south central Canada (Ogden et al. 2009, 2010; Bouchard et al. 2011; Leighton et al. 2012), and the diseases transmitted by I. scapularis represent a dynamic and emerging public health challenge in Canada (Ogden et al. 2005). I. scapularis is a host generalist parasitizing several species, such as rodents, birds, medium-and large-sized mammals, and reptiles (Tsao 2009). However, the positive correlation between I. scapularis abundance and white-tailed deer (Odocoileus virginianus) density is well documented in eastern
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Papers by Catherine Bouchard