Toward a Systems Approach to Enteric Pathogen Transmission: From Individual Independence to Community Interdependence

Abstract

Diarrheal disease is still a major cause of mortality and morbidity worldwide; thus a large body of research has been produced describing its risks. We review more than four decades of literature on diarrheal disease epidemiology. These studies detail a progression in the conceptual understanding of transmission of enteric pathogens and demonstrate that diarrheal disease is caused by many interdependent pathways. However, arguments by diarrheal disease researchers in favor of attending to interaction and interdependencies have only recently yielded more formal systems-level approaches. Therefore, interdependence has not yet been highlighted in significant new research initiatives or policy decisions. We argue for a systems-level framework that will contextualize transmission and inform prevention and control efforts so that they can integrate transmission pathways. These systems approaches should be employed to account for community effects (i.e., interactions among individuals and/or households).

Toilets Can Work: Short and Medium Run Health Impacts of Addressing Complementarities and Externalities in Water and Sanitation

“…The F-diagram is also useful in making clear the interdependence of different interventions and behaviors (Eisenberg et al 2012). In a community with a high load of fecal-oral pathogens and several modes of transmission, any intervention that blocks one transmission mechanism may have little effect on health on its own, but a combination of such interventions may be effective (PrussUstun et al 2004).…”

“…In a community with a high load of fecal-oral pathogens and several modes of transmission, any intervention that blocks one transmission mechanism may have little effect on health on its own, but a combination of such interventions may be effective (PrussUstun et al 2004). This is especially likely where levels of fecal-oral pathogens are high, since the relationship between dose and infection probability is likely to be relatively flat at high levels of exposure (Eisenberg et al 2012). Alternatively, the effects of interventions could be independent, especially in places with intermediate pathogen levels (where the relationship between pathogen levels and infection is believed to be roughly log-linear (VanDerslice and Briscoe 1995)), where the interventions operate on independent mechanisms (Cairncross and Valdmanis 2006) and without significant feedback between transmission mechanisms (Eisenberg, Scott, and Porco 2007).…”

Hand washing promotion for preventing diarrhoea

“…Also, hand washing may require infrastructural, cultural, and behavioural changes, which take time to develop, as well as substantial resources (for example, trained personnel, community organization, provision of water supply and soap) (Luby 2001a; UNICEF/WHO 2009). Consideration of the wide applicability and sustainability of hygiene interventions have recently come under critical review (Luby 2006 PAK; Ejemot-Nwadiaro 2008; Gould 2010; Curtis 2011; Huis 2012; Madhu 2012). For example, maintenance of the new hand washing behaviours that result from hand washing promotional interventions is vital in maximizing the associated potential health benefits.…”

Design and rationale of a matched cohort study to assess the effectiveness of a combined household-level piped water and sanitation intervention in rural Odisha, India

“…There is growing emphasis on assessing health risk from poor water and sanitation conditions not simply due to individual or even household-level risk factors, but also from conditions in the community environment. 17 There is evidence that even households without toilets, and households which do not filter drinking water, showed decreased health risk if they live in communities with high levels of coverage and use. [18][19][20] Moreover, the effectiveness of community interventions may be higher in communities with positive perceptions of their collective ability to come together to improve their conditions.…”