Selección de las Variables del Experimento

Traditionally public health research, policy, and practice focused on environmental and societal issues separately. Public health research that explored the parameters of the social determinants of health often came to the conclusion that health inequities were a significant part of ill health which appeared to exemplify the social determinants of health as the root cause. Very little

consideration was given to the physical, environmental, and ecological systems when conducting public health research (Mikkonen and Raphael 2010; Parkes 2010).

As a result, public health research was conducted through a lens which focused on the biomedical or social determinants of health model solely (Ruderman 2013). The biomedical model can inform population health indicators that public health is concerned with; however, unlike the medical model, population based models take a much extensive view of population health over a lifespan span. According to Fielding et al 2012, the ecological health model ―…emphasizes the importance of the social and physical environments that strongly shape patterns of disease and injury as well as our responses to them over the entire life cycle,‖ (Fielding et al 2012, page 175).

Research in public health that focused solely on environmental conditions that had the potential to affect human health in terms of increased morbidity or mortality was skewed heavily towards environmental health. For example, toxic chemicals or contaminants that could be present in our food, water or in the soil were at the foreground of this research. The goal of this research was to determine effective mitigation measures to reduce the impact of environmental contaminants from the soil, from water or from food (Parkes et al 2003). According to Parkes (2010), this traditionally held view overlooked the societal processes that had the potential to augment health impacts and to prompt environmental change (Parkes 2010). Greenwood and de Leeuw (2009) believed that the simplification reduced the understanding of the synergistic effect of both the environmental and social factors that can have an impact on health (Greenwood and de Leeuw 2009).

From the fields of human development and psychology is the foundation of the ecological health model, exploring in research the link between the individual and the environment in human behaviour in the 1980s (Fielding et al 2012; Ruderman 2013). Theories within public health research also began to shift at the same time, from individual-based theories such as the health belief model and the trans-theoretical model to the multi-layered ecological health model (Ruderman 2013). The individual factors, for example age, were still integral to understanding disease from a public health standpoint; however, with the ecological health model, broader social, ecological and environmental issues are part of the landscape that has the potential to affect health outcomes (Fielding et al 2012; Frieden 2010).

Public health research, policy, and practice currently aim to address the established divide between environmental and social views on health (Bircher et al 2014). This is to highlight the connection between ecosystems, equity, and health (Parkes 2010, CSDH, 2008). There has been a recognition of the combination of environmental /ecological and social determinants of health as interconnected determinants of health (Parkes 2003; Ruderman 2013) The ecological health model is what many in public health believe to be the original intent of the Ottawa Charter for health promotion a more integrative approach to public health (Fielding et al 2012; De Plaen and Kilelu 2004). This is a systemic progression from traditional concepts that places health

inequities with regards to social and environmental conditions at the forefront (Fielding et al 2012; De Plaen and Kilelu 2004).

Dean et al (2013) and Watt (2002) also suggest that implementing any action on social determinants of health requires the understanding of the behavioural and environmental / ecological determinants of health. The ecological health model has evolved from health knowledge that has begun to understand the multiple interconnections that exist, and include

both the social and the biophysical determinants of health and their disparities. As a result, public health researchers are beginning to revise their conceptual framework models and adjust their research methods (Arredondo and Orozco 2012; Barkin and Schlundt 2011; Bircher et al 2014). Nowhere is this more pertinent in public health research than in the study of infectious diseases. The majority of infectious diseases, especially those belonging to the neglected tropical diseases, have a component of the risk of transmission that includes social and ecological/ environmental components. As a result, public health researchers into dengue are beginning to revise their conceptual framework models and adjust their research methods (Arredondo and Orozco 2012; De Mattos 2007; Hagenlocher et al 2013; IDRC 2010).

In the past public health researchers found that studies into mitigation measures, such as

integrated vector management and routine interventions against the larval stages of the mosquito, can reduce the mosquito vector and thereby reduce the transmission risk to the population but it is not an always an effective approach (Murray et al 2013). In fact, standalone interventions often have short-lived success (Hagenlocher et al 2013). This is due to the fact that the variables that influence vector breeding of the Aedes aegypti mosquito can be quite complex and can be due to several different factors (Aruncachalam et al 2014). The ecological health model is essentially a systems approach to uncover vulnerabilities to disease within a population. Its fundamental premise is to be inclusive by analysing these components based on the intersection of these three elements. The benefit for research of generating interventions and health program based on the evidence under the ecological health model is to provide a more cost-effective and preventative public health intervention (Arredondo 2012; Aruncachalam et al 2014; Bircher et al 2014).