Modeling the spatial distribution of African buffalo (Syncerus caffer) in the Kruger National Park, South Africa

The population density of wildlife reservoirs contributes to disease transmission risk for domestic animals. The objective of this study was to model the African buffalo distribution of the Kruger National Park. A secondary objective was to collect field data to evaluate models and determine environmental predictors of buffalo detection. Spatial distribution models were created using buffalo census information and archived data from previous research. Field data were collected during the dry (August 2012) and wet (January 2013) seasons using a random walk design. The fit of the prediction models were assessed descriptively and formally by calculating the root mean square error (rMSE) of deviations from field observations. Logistic regression was used to estimate the effects of environmental variables on the detection of buffalo herds and linear regression was used to identify predictors of larger herd sizes. A zero-inflated Poisson model produced distributions that were most consistent with expected buffalo behavior. Field data confirmed that environmental factors including season (P = 0.008), vegetation type (P = 0.002), and vegetation density (P = 0.010) were significant predictors of buffalo detection. Bachelor herds were more likely to be detected in dense vegetation (P = 0.005) and during the wet season (P = 0.022) compared to the larger mixed-sex herds. Static distribution models for African buffalo can produce biologically reasonable results but environmental factors have significant effects and therefore could be used to improve model performance. Accurate distribution models are critical for the evaluation of disease risk and to model disease transmission

تنظيم نقشه‌ جغرافيايی ميزان بروز سرطان روده بزرگ در ايران طی سال‌های 1386-1382 با استفاده از روش کريگيدن پواسنی منطقه به منطقه

زمينه و هدف : سرطان روده بزرگ دومين رتبه در بين سرطان‌های دستگاه گوارش و چهارمين سرطان شايع در کشور ايران است. مطالعه‌ی حاضر به هدف تبيين توزيع جغرافيايی سرطان روده بزرگ با روش دقيق کريگيدن پواسنی منطقه به منطقه در سطح کليه شهرستان‌های ايران و شناسايی مناطق پر خطر انجام گرفت. روش کار : اين مطالعه از نوع کاربردی/ بوم‌شناسی است و از داده‌های ثبت شده توسط اداره سرطان مرکز مديريت بيماری‌های غير واگير وزارت بهداشت درمان و آموزش پزشکی استفاده شد. داده‌هايی که در سطح 336 شهرستان و در طول سال‌های 1382 تا 1386 جمع‌آوری شده است، مورد تجزيه و تحليل قرار گرفت. نرم‌افزار Spacestat برای برآورد پارامترها و نرم‌افزار ArcGIS 9.3 برای نمايش برآوردها بر روی نقشه به کار گرفته شدند. يافته ‌ ها: ميانگين ميزان بروز براساس روش کريگيدن پواسنی منطقه به منطقه(90/1) و ميانگين واريانس ميزان بروز (25/0) برآورد شده است. بيشترين ميزان بروز (65/5) با واريانس (04/0) مربوط به شهرستان رشت وکمترين ميزان بروز (05/0) با واريانس (14/0)مربوط به شهرستان چابهار برآورد شده است. کمترين واريانس (01/0) مربوط به تهران با برآورد خطر(64/3) و بيشترين واريانس (51/2)مربوط به دير با برآورد خطر(15/1) برآورد شده‌ است. نتيجه ‌ گيری : با توجه به برازش مناسب روش کريگيدن پواسنی منطقه به منطقه در مناطق ناهمگن فضايی، استفاده از اين روش در نقشه‌بندی بيماری پيشنهاد می‌شود. اين مطالعه نشان داد که در شهرستان‌های استان‌های گيلان و مازندران ميزان بروز بيماری بيشتر است

The frequency of four common cancers in Kermanshah City, Iran, during the years 2004-2011

BACKGROUND: Cancer is one of the most prevalent diseases in today’s civilized world, with an increasing number of sufferers with each passing day. The aim of this study was to determine the prevalence of common cancers in Kermanshah City, Iran, in a period of eight years between 2004 and 2011.METHODS: This was a historic cohort study. Data were collected from Kermanshah Province Health Center (Cancer Registry). Data analysis was performed using SPSS software.RESULTS: 6,146 people were diagnosed with cancer in Kermanshah during these eight years. The prevalence of skin, stomach, breast, and bladder cancers, without considering the patients’ genders, was 35.24, 24.58, 23.73, and 16.45 percent, respectively. The highest frequency belonged to skin cancer with 309 persons in 2007.CONCLUSION: Considering the fact that cancer has increased in the city of Kermanshah, it is necessary to change the lifestyle of all the people in order to prevent and reduce different types of cancer. Managers, officials, and health professionals are the most suitable individuals that can start changing the lifestyle, habits, and the improper way of living in this community

The frequency of four common cancers in Kermanshah City, Iran, during the years 2004-2011

BACKGROUND: Cancer is one of the most prevalent diseases in today’s civilized world, with an increasing number of sufferers with each passing day. The aim of this study was to determine the prevalence of common cancers in Kermanshah City, Iran, in a period of eight years between 2004 and 2011. METHODS: This was a historic cohort study. Data were collected from Kermanshah Province Health Center (Cancer Registry). Data analysis was performed using SPSS software. RESULTS: 6,146 people were diagnosed with cancer in Kermanshah during these eight years. The prevalence of skin, stomach, breast, and bladder cancers, without considering the patients’ genders, was 35.24, 24.58, 23.73, and 16.45 percent, respectively. The highest frequency belonged to skin cancer with 309 persons in 2007. CONCLUSION: Considering the fact that cancer has increased in the city of Kermanshah, it is necessary to change the lifestyle of all the people in order to prevent and reduce different types of cancer. Managers, officials, and health professionals are the most suitable individuals that can start changing the lifestyle, habits, and the improper way of living in this community

Genetic responsiveness of African buffalo to environmental stressors : a role for epigenetics in balancing autosomal and sex chromosome interactions?

In the African buffalo (Syncerus caffer) population of the Kruger National Park (South Africa) a primary sex-ratio distorter and a primary sex-ratio suppressor have been shown to occur on the Y chromosome. A subsequent autosomal microsatellite study indicated that two types of deleterious alleles with a negative effect on male body condition, but a positive effect on relative fitness when averaged across sexes and generations, occur genome-wide and at high frequencies in the same population. One type negatively affects body condition of both sexes, while the other acts antagonistically: it negatively affects male but positively affects female body condition. Here we show that high frequencies of male-deleterious alleles are attributable to Y-chromosomal distorter-suppressor pair activity and that these alleles are suppressed in individuals born after three dry pre-birth years, likely through epigenetic modification. Epigenetic suppression was indicated by statistical interactions between pre-birth rainfall, a proxy for parental body condition, and the phenotypic effect of homozygosity/heterozygosity status of microsatellites linked to male-deleterious alleles, while a role for the Y-chromosomal distortersuppressor pair was indicated by between-sex genetic differences among pre-dispersal calves. We argue that suppression of male-deleterious alleles results in negative frequencydependent selection of the Y distorter and suppressor; a prerequisite for a stable polymorphism of the Y distorter-suppressor pair. The Y distorter seems to be responsible for positive selection of male-deleterious alleles during resource-rich periods and the Y suppressor for positive selection of these alleles during resource-poor periods. Male-deleterious alleles were also associated with susceptibility to bovine tuberculosis, indicating that Kruger buffalo are sensitive to stressors such as diseases and droughts. We anticipate that future genetic studies on African buffalo will provide important new insights into gene fitness and epigenetic modification in the context of sex-ratio distortion and infectious disease dynamics.S1 Fig. Map with locations of the rainfall stations and the sampled herds.S2 Fig. Regression between fraction HBC among BTB-negative females and BTB prevalence per herd.S1 Table. Logistic regression southern females with body condition status as dependent variable (highest ranking model).S2 Table. Logistic regression southern males with body condition status as dependent variable (highest ranking model).S3 Table. Logistic regression southern females with BTB status as dependent variable (highest ranking model).S4 Table. Logistic regression southern males with BTB status as dependent variable (highest ranking model).S5 Table. Logistic regression northern females with body condition status as dependent variable (highest ranking model).S6 Table. Logistic regression southern males with BTB status as dependent variable (Evidence Ratio = 1.9).S7 Table. Logistic regression northern males with body condition status as dependent variable (Evidence Ratio = 2.1).S8 Table. Significance of the genetic-measure by annual-rainfall interaction per single year.S9 Table. Logistic regression northern females with body condition status as dependent variable (Evidence Ratio = 1.8).S10 Table. Results Hedges' g analyses (group differences with respect to MDLmale and MDLfemale).S1 Text. Consistency of the model outcomes.Laboratory analyses were supported by US NIH/NSF Ecology of Infectious Disease Grant GM83863 awarded to WMG.http://www.plosone.orgam2018Mammal Research InstituteZoology and Entomolog

Piospheres in semi-arid rangeland: Consequences of spatially constrained plant-herbivore interactions

This thesis explains two aspects of animal spatial foraging behaviour arising as a direct consequence of animals' need to drink water: the concentration of animal impacts, and the response of animals to those impacts. In semi-arid rangelands, the foraging range of free-ranging large mammalian herbivores is constrained by the distribution of drinking water during the dry season. Animal impacts become concentrated around these watering sites according to the geometrical relationship between the available foraging area and the distance from water, and the spatial distribution of animal impacts becomes organised along a utilisation gradient termed a "piosphere". During the dry season the temporal distribution of the impacts is determined by the day-to-day foraging behaviour of the animals. The specific conditions under which these spatial foraging processes determine the piosphere pattern have been identified in this thesis. At the core of this investigation are questions about the response of animals to the heterogeneity of their resources. Aspects of spatial foraging are widely commented on whilst explaining the consequences of piosphere phenomena for individual animal intake, population dynamics, feeding strategies and management. Implicated are our notions of optimal foraging, scale in animal response, and resource matching. This thesis addressed each of these. In the specific context of piospheres, the role of energy balance in optimal foraging was also tested. Field experiments for this thesis showed a relationship between goat browsing activity and measures of spatial impact. As a preliminary step to investigating animal response to resource heterogeneity, the spatial pattern of foraging behaviour/impacts was described using spatial statistics. Browsing activity varied daily revealing animal assessment of the spatial heterogeneity of their resources and an energetic basis for foraging decisions. This foraging behaviour was shown to be determined by individual plants rather than at larger scales of plant aggregation. A further experiment investigated the claim that defoliation has limited impact on browser intake rate, suggesting that piospheres may have few consequences for browser intake. This experiment identified a constraining influence of browse characteristics at the small scale on goat foraging by relating animal intake rate to plant bite size and distribution. Computer simulation experiments for this thesis supported these empirical findings by showing that the distribution of spatial impacts was sensitive to the marginal value of forage resources, and identified plant bite size and distribution as the causal factors in limiting animal intake rate in the presence of a piosphere. As a further description of spatial pattern, piospheres were characterised by applying a contemporary ecological theory that ranks resource patches into a spatial hierarchy. Ecosystem dynamics emerge from the interactions between these patches, with piospheres being an emergent property of a natural plant-herbivore system under specific conditions of constrained foraging. The generation of a piosphere was shown to be a function of intake constraints and available foraging area, whilst piosphere extent was shown to be independent of daily energy balance including expenditure on travel costs. A threshold distance for animal foraging range arising from a hypothesised conflict between daily energy intake and expenditure was shown not to exist, whereas evidence for an intermediate distance from water as a focus for accumulated foraging activity was identified. Individual animal foraging efficiency in the computer model was shown to be sensitive to the piosphere, while animal population dynamics were found to be determined in the longer term by dry season key resources near watering points. Time lags were found to operate in the maintenance of the gradient, and the density dependent moderation of the animal population. The latter was a direct result of the inability of animal populations to match the distribution of their resources with the distribution of their foraging behaviour, because of their daily drinking requirements. The result is that animal forage intake was compromised by the low density of dry season forage in the vicinity of a water point. This thesis also proposes that piospheres exert selection pressures on traits to maximise energy gain from the spatial heterogeneity of dry season resources, and that these have played a role in the evolution of large mammalian herbivores

A new approach to adaptive monitoring

Invasive species are an increasing problem, costing several billion dollars to the global economy. Monitoring methods are needed to provide scientists the necessary information to control populations of invasive species. Adaptive monitoring means that, for each additional survey, the monitoring design is updated based on the information obtained during the previous surveys. In this thesis we introduce a new general framework for adaptive monitoring. This method focuses on increasing the detection rate of invasive species over consecutive surveys. Compared with the existing monitoring methods, the proposed algorithm aims to improve adaptive monitoring by the following three points: (1) The use of a spatially balanced sampling design to select a sample in each survey, (2) by using both spatial and ecological information to update the monitoring strategy, and (3) by incorporating an eradication strategy to an adaptive monitoring design. In Chapter 1, we emphasise the need for the development of adaptive monitoring methods for invasive species. In Chapter 2, we outline the algorithm of our proposed method for adaptive monitoring and discuss the use of spatially balanced sampling designs. In Chapter 3, several sampling designs are introduced and their use for (adaptive) monitoring is evaluated. We give special attention to a new spatially balanced sampling design, named Balanced Acceptance Sampling, and compare it with a selection of existing (spatially balanced) sampling designs such as Generalized Random Tessellation Stratified sampling. In Chapter 4, we illustrate how ecological information can be used to update the monitoring strategy, which is demonstrated using a case study on the Asian tiger mosquito. In addition, several practical issues with probability sampling are discussed. In Chapter 5, the Nearest Unit Tessellation methods are introduced. These methods can model the observed spatial information of the species to update the monitoring strategy. Finally, we demonstrate how to combine ecological and spatial information to adjust a monitoring strategy. Chapter 6 also explores the use of a method to incorporate an eradication strategy to an adaptive monitoring strategy, using the Great White Butterfly data

Investigation of the invasion dynamics of Asparagus asparagoides at the habitat level using spatial analytical techniques

This thesis reports on research that examines the early stage invasion process of Asparagus asparagoides (L.) W. Wight (bridal creeper), primarily a bird-dispersed weed, in a remnant vegetation patch. The study site is on Phillip Island, approximately 100 kilometres south east of Melbourne, Victoria. Asparagus asparagoides invasion of the remnant vegetation reserve is a relatively recent phenomenon. Landscape elements that affect bird dispersal and vegetation types that affect seedling establishment may be important factors that limit or enhance the spread of A. asparagoides. A systematic sampling strategy was adopted and data collected for a variety of landscape and vegetative variables including cover and abundance of A. asparagoides and the data were presented in a Geographic Information System (GIS). Preliminary results show that the distribution of A. asparagoides within a remnant vegetation patch is not random. It appears to have entered the reserve from two boundaries, spreading toward the centre, which to date remains sparsely colonised despite the capacity of this weed to spread rapidly over long distances by birds. A number of other outcomes are noted. Asparagus asparagoides establishment is prevented in pasture where sheep and cattle graze, and paddocks subjected to tillage practices. The exclusion of grazing in fenced off vegetation in pastures demonstrates rapid weed establishment and colonisation several hundred metres from main infestation. Field observation and visual inspection of temporal progress of invasion (using above ground weed density with tuber appearance to infer age) appear to suggest that invasion into remnant is associated with the track network. This age/density assumption is strengthened when spatial distribution is examined using a data set where low-density values for A. asparagoides are removed and compared with a data set using all A. asparagoides density values. The mapping of A. asparagoides in fenced off farm remnants suggests that velocity of spread at 191m/yr is a considerable underestimate. Subsequent analysis shows that the spatial distribution of A. asparagoides is not completely spatially random while intensity surface analysis highlights regions of low and high intensity located near track network. Mapping a density surface within GIS provided confirmatory evidence for the establishment of satellite clusters along the track network. The change in the intensity surface observed using the two data sets (lowdensity values and all density values) is also consistent with an expanding invasion occurring between two time periods. Spatial point pattern analysis using K-function statistics shows that xxii the clustering observed using GIS appears to be occurring at two scales or distances (130m- 160m and 195m-205m). The association between tracks and the invasion process observed in the initial stages of the study is examined. There is a change in density as a function of distance from a track where the density of A. asparagoides appears to reduce the further away from the track a site is and this relationship holds regardless of track width. The final stages of the study look at the development of a predictive model. Visual exploration of the data through mapping in a GIS and field observation made during data collection provide the starting point for the development of logistic models to estimate the probability of A. asparagoides presence. Finally the best overall logistic model is applied to a second independent site to determine the general applicability of the model. A number of variables that impact on the presence of A. asparagoides, particularly during the initial stages of the invasion process, are identified. While all the identified variables and the overall model are statistically significant, the model is found to correctly predict presence/absence in only 67% of cases overall. The model however could be expected to correctly predict the presence of A. asparagoides in 74% of cases and has a false positive rate of 40%. The model is applied at a second independent site and found to have an overall percent correct rate of 80% and correctly predicted A. asparagoides presence in 94% of cases. The variables identified as influential in the early stage of invasion are relatively easy to acquire by simple field survey that does not require specialist skills. When considering the model as a tool for the management of remnant vegetation communities, high false positive rates may lead to limited resources being spent on searching sites where there is no weed. However, a high false negative rate would have a larger impact on the management of the weed since the undetected infestations would form sources for new propagules. The model performs well from this point of view in that it provided low false negative rates at both sites. The value of the predictive model is its ability to provide managers with information regarding specific areas to target for weed eradication and management can use the model to assess the effectiveness of any control measures by going back to obtain new cover density data, then using the model to examine the changes over time. The model also provides a starting point for the development of a generic model of A. asparagoides invasion at sites outside of Phillip Island and could also provide the starting point for developing models that could be used for other bird-dispersed fleshy-fruited weed species

Éco-épidémiologie spatiale de la tique à pattes noires et de ses pathogènes dans un parc naturel du sud du Québec

Cette thèse est une investigation de l'écologie et de l'épidémiologie spatiale fine de la tique à pattes noires (Ixodes scapularis) et du risque associé aux pathogènes transmis par cette tique dans une forêt du sud du Québec, au Canada. Sous l’influence de changements climatiques et environnementaux, la répartition spatiale de cette tique s’étend actuellement à travers la province, et son abondance augmente dans la plupart des régions. Il en résulte une préoccupation croissante en matière de santé publique liée à l'émergence de maladies transmises par les tiques (MTT) dans la province. Ainsi, plusieurs besoins de recherche ont vu le jour, y compris l’amélioration de la compréhension des facteurs dictant où et quand le risque émergera, et l’identification des composantes sur lesquelles les autorités régionales, locales et les individus pourraient agir afin réduire ce risque. Le site d’étude pour ce projet était le parc National du Mont-Saint-Bruno. De 2016 à 2018, à 32 sites répartis dans les habitats forestiers du parc, les tiques ont été collectées par la technique de la flanelle, la communauté d’hôtes de la tique a été inventoriée (grands et petits mammifères, et oiseaux nicheurs) et les micro-habitats ont été caractérisés (en termes de structure, de composition et de conditions microclimatiques). La densité des tiques dans la zone d’étude était particulièrement élevée par rapport aux autres régions environnantes. Les analyses spatiales ont montré des patrons d’abondance des tiques, persistants sur trois ans, avec un effet significatif des conditions locales de températures et d’humidité relatives. Un effet significatif de la densité du stade de développement précédent lors de l’année précédente a également été noté, suggérant une dispersion lente des tiques par les hôtes et une dynamique d’invasion caractérisée par plusieurs évènements d’introduction et d’expansion opérant à une échelle locale. En 2017 et 2018, un dispositif d’échantillonnage plus extensif a visé la communauté d’hôtes des stades immatures d’I. scapularis, afin de documenter le rôle de ces espèces dans la circulation des agents pathogènes. 849 oiseaux nicheurs appartenant à 50 espèces et 694 petits mammifères appartenant à 4 espèces ont été examinés pour la présence des tiques et des pathogènes. Les souris à pattes blanches (Peromyscus leucopus) contribuaient à la majorité (80%) des cas d’infection des nymphes par Borrelia burgdorferi dans l’échantillon, alors que les 20% restants étaient attribuables à des oiseaux. Ce résultat confirme la proposition de certains auteurs à savoir que l’importance des hôtes alternatifs (autres que P. leucopus) aient été sous-estimée dans les études précédentes, et souligne l’importance de poursuivre les travaux pour documenter l’impact de ces hôtes dans l’épidémiologie des MTT. Finalement, la caractérisation des patrons de risque associés aux MTT dans la zone d’étude a été complétée par un échantillonnage de l’intensité d’utilisation des sentiers par les visiteurs du parc en 2017 et 2018. D’abord, les prélèvements de tiques dans l’environnement et sur les hôtes ont permis de détecter la présence de trois pathogènes représentant un risque de santé publique pour la population locale, soit en ordre du plus au moins prévalent : B. burgdorferi, Anaplasma phagocytophyllum et Borrelia miyamotoi. Ensuite, l’intégration des patrons spatiaux de l’utilisation du parc par les visiteurs a mis en évidence le rôle des facteurs comportementaux des utilisateurs et des attributs du paysage local dans la détermination des patrons de risque de contacts entre les visiteurs et les nymphes infectées par B. burgdorferi. Le risque de contact était associé à certaines périodes et zones de forte fréquentation du parc, mais pas aux indicateurs locaux de fragmentation de l'habitat, comme le suggèrent d'autres études. En outre, les zones où la densité de la couverture forestière et des points d'intérêt (infrastructures) étaient les plus élevés présentaient les niveaux de risque les plus élevés. Cette thèse contribue à l’avancement des connaissances fondamentales reliées à la biologie des tiques, aux relations écologiques entre ces ectoparasites et leurs hôtes et à l’écologie des pathogènes qu’elles transmettent. Ces connaissances trouveront de multiples applications concrètes, principalement dans le domaine de la santé publique où elles permettront notamment de parfaire les outils existants d’évaluation du risque et de prévention des MTT. En reliant l’écologie à la santé publique, cette thèse répond à un besoin de recherche et de développement d’expertise qui devient de plus en plus important dans le contexte actuel des changements climatiques et de l’émergence des maladies zoonotiques qui s’en trouvent facilitées au Canada.This thesis is an investigation of the ecology and fine-scale spatial epidemiology of the blacklegged tick (Ixodes scapularis) and the risk associated with pathogens transmitted by this tick in a forest of southern Quebec, Canada. Under the influence of climate and environmental changes, the spatial distribution of this tick is currently expanding across the province, and its abundance is increasing in most regions. This has resulted in a growing public health threat associated with the emergence of tick-borne diseases (TBDs) in the province. Thus, several research needs have emerged, including improving understanding of the factors determining where and when risk will arise, and identifying what regional and local health authorities and individuals can do to reduce that risk. The study site for this project was Mont-Saint-Bruno National Park. From 2016 to 2018, at 32 sites distributed in the park's forest habitats, ticks were collected by drag sampling, the host community was inventoried (large and small mammals, and nesting birds), and microhabitats were characterized (in terms of structure, composition, and microclimatic conditions). The density of ticks in the study area was particularly high compared to other surrounding areas. Spatial analyses showed patterns of tick abundance, persistent over three years, with a significant effect of local microclimatic conditions (relative temperature and humidity). A significant effect of the density of the previous developmental stage in the previous year was also noted, suggesting slow host dispersal of ticks and invasion dynamics characterized by several introduction and expansion events operating at a local scale. In 2017 and 2018, a more extensive sampling scheme targeted the host community of immature stages of I. scapularis, to document the role of these species in pathogen circulation. 849 breeding birds belonging to 50 species and 694 small mammals belonging to 4 species were examined for the presence of ticks and pathogens. White-footed mice (Peromyscus leucopus) contributed to the majority (80%) of Borrelia burgdorferi nymph infections in the sample, while the remaining 20% were attributable to birds. This result confirms the suggestion by some authors that the importance of alternative hosts (other than P. leucopus) may have been underestimated in previous studies and underscores the importance of further work to document the impact of these hosts in the epidemiology of TBDs. Finally, characterization of risk patterns associated with TBDs in the study area was completed by sampling trail use by park visitors in 2017 and 2018. First, the analysis of ticks collected from the environment and on hosts demonstrated the presence of three pathogens representing a public health risk to the local population, in order from the most to the least prevalent: B. burgdorferi, Anaplasma phagocytophyllum and Borrelia miyamotoi. Second, integration of spatial patterns of visitor use of the park highlighted the role of visitor behaviour and local landscape attributes in determining patterns of risk of contact between visitors and B. burgdorferi-infected nymphs. Risk was associated with certain times and areas of increased park use, but not with local indicators of habitat fragmentation, in contrast with the results of previous studies. In addition, areas with the highest densities of forest cover and points of interest (infrastructure) had the highest levels of risk. This thesis contributes to the advancement of fundamental knowledge related to the biology of ticks, the ecological relationships between these ectoparasites and their hosts, and the ecology of the pathogens they transmit. This knowledge will have multiple applications, mainly in the field of public health, where it will allow the refinement of existing tools for risk assessment and prevention of TBDs. By linking ecology to public health, this thesis responds to a need for research and development of expertise that is becoming increasingly important in the current context of climate change and the emergence of zoonotic diseases that it facilitates in Canada