HISTORICAL POPULATION HEALTH: SPATIOTEMPORAL MORTALITY PATTERNS OF HAMILTON, ONTARIO 1880–1882 AND 1910–1912

This dissertation empirically investigates multifaceted causes of health inequity by exploring historical connections between shifting economic activity, urban development, population change, and mortality. The purpose is to reveal the impact of changing socioeconomics on population structure and urban development, and the association of this impact on spatiotemporal mortality patterns. This research advances knowledge on the complex ecological interplay of population, behaviour, habitat, and subsequent health inequities, revealing a link between health disparities and economic transitions. Examining Hamilton, Ontario, at two cross-sections (1880–1882 and 1910–1912), using purposive working-age and infant samples provides a snapshot of life and death before and during heavy industrial activity. Mixed-methods use data from census and death records, health reports, photographs, and maps to construct a profile of demography, epidemiology, and the urban environment (physical, built, and social). Two major findings are identified: 1) industrialization played a major role in emerging human health ecology risks correlating to the mortality patterns; and 2) industrialization tended to increase health inequities amongst the population and across the city. The onset of predominately industrial economic activity caused further class divide, uneven urban development, and inequitable health outcomes. Statistical inquiry (multiple logistic regression) of the working-age mortality sample revealed an increased association between age at death and dying of tuberculosis, and an increased association between accidental death with biological sex, age at death, and birthplace. The infant mortality sample revealed a temporal shift with an increased association between diarrhoeal mortality and infant age, and between infectious respiratory mortality and infant age. Results from Historical GIS inquiry indicate residential working-class sections were more unhealthy environments than other areas of the city. Historical documentation and photographs supported these results, presenting the likelihood of a social disparity to health outcomes. The interplay between population, environment, and behaviour manifests into a spatiotemporal pattern of stressors related to socioeconomic status, urban development, and health disparity. Industrialization brought new stressors to Hamilton creating unequal opportunities for the rapidly growing working classes. Thus, without careful planning in urban development, concentrations of health risks lead to inequitable population health outcomes, especially those undergoing an economic transition, such as industrialization

Ultrasensitive detection of toxocara canis excretory-secretory antigens by a nanobody electrochemical magnetosensor assay.

peer reviewedHuman Toxocariasis (HT) is a zoonotic disease caused by the migration of the larval stage of the roundworm Toxocara canis in the human host. Despite of being the most cosmopolitan helminthiasis worldwide, its diagnosis is elusive. Currently, the detection of specific immunoglobulins IgG against the Toxocara Excretory-Secretory Antigens (TES), combined with clinical and epidemiological criteria is the only strategy to diagnose HT. Cross-reactivity with other parasites and the inability to distinguish between past and active infections are the main limitations of this approach. Here, we present a sensitive and specific novel strategy to detect and quantify TES, aiming to identify active cases of HT. High specificity is achieved by making use of nanobodies (Nbs), recombinant single variable domain antibodies obtained from camelids, that due to their small molecular size (15kDa) can recognize hidden epitopes not accessible to conventional antibodies. High sensitivity is attained by the design of an electrochemical magnetosensor with an amperometric readout with all components of the assay mixed in one single step. Through this strategy, 10-fold higher sensitivity than a conventional sandwich ELISA was achieved. The assay reached a limit of detection of 2 and15 pg/ml in PBST20 0.05% or serum, spiked with TES, respectively. These limits of detection are sufficient to detect clinically relevant toxocaral infections. Furthermore, our nanobodies showed no cross-reactivity with antigens from Ascaris lumbricoides or Ascaris suum. This is to our knowledge, the most sensitive method to detect and quantify TES so far, and has great potential to significantly improve diagnosis of HT. Moreover, the characteristics of our electrochemical assay are promising for the development of point of care diagnostic systems using nanobodies as a versatile and innovative alternative to antibodies. The next step will be the validation of the assay in clinical and epidemiological contexts