Ticks, hosts, habitats, and humans: A One Health approach for  investigating Lyme borreliosis risk in Ireland

Lyme borreliosis (or Lyme disease) is a zoonotic infection, transmitted to humans via the bite of a tick which is carrying a pathogenic genospecies of the Borrelia burgdorferi sensu lato bacterial complex. As a zoonotic disease, a One Health approach is necessary to fully understand Lyme disease risk. Furthermore, while the geographic range of both pathogen and vector is broad, differences in pathogen genospecies, vector species, habitats, and host assemblages between regions means that the drivers of Lyme borreliosis risk vary geographically. While Lyme borreliosis epidemiology, ecology, and risk may be better understood in some regions of Europe, significant knowledge gaps remain in relation to Lyme borreliosis in Ireland. These include the geographic and demographic variability in the epidemiology of Lyme borreliosis in Ireland; the effect of various host, habitat, and abiotic factors on ecological markers of disease risk; and the disease awareness and perceptions of at-risk groups. To address these knowledge gaps, a One Health, trans-disciplinary approach to examining Lyme disease in Ireland, incorporating methods from the disciplines of epidemiology, ecology, and social science have been adopted in this study. Using meta-analytic and field study techniques, the ecological markers of disease risk (nymphal tick abundance, nymphal tick infection prevalence, density of infected nymphs) have been defined for Ireland, and discussed in the context of data obtained from an epidemiological observational analysis. This work also assessed the drivers of the above markers of disease risk. Results suggest that woodland habitat factors (such as size and type) can affect nymphal infection prevalence. We have also found that nymphal abundance (and therefore bite risk) peaks in April, has an inverse and seasonal relationship with deer activity, and an inverse relationship with robin activity. Finally, a study of individuals whose occupation or recreational activities increase their exposure to Lyme borreliosis has generated information on risk perceptions, awareness, disease knowledge, and training levels amongst this cohort in Ireland. We have identified a lack of geographical variability in perceived risk, a lack of training amongst at-risk groups, and knowledge gaps in relation to risk habitats and disease symptoms. The abovementioned findings of this work have implications for the future study of human populations, ticks, wildlife hosts, and the Lyme borreliosis pathogen in Ireland. The findings also have implications for the design, timing, and implementation of future awareness campaigns aiming to decrease Lyme borreliosis risk in Ireland.

Publisher

University of Galway

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CC BY-NC-ND

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University of Galway Theses (PhD Theses)