Environmental transmission of diarrheal pathogens in low and middle income countries

Abstract

Every year, more than half a million children die due to diarrheal diseases. Recent studies have identified the most important etiologies of diarrheal disease are enterotoxigenic and enteropathogenic E. coli, Shigella spp., rotavirus, norovirus and Cryptosporidium spp. These etiologies are unsurprisingly characterized by a combination of high shedding, high infectivity, and transmissibility through multiple environmental reservoirs. The relative importance of the transmission routes is likely site-specific. So the impact of interventions, which typically target only one or two environmental reservoirs, is likely also site-specific. The factors influencing the transmission routes most important for diarrheal disease are complex, including - at a minimum - etiology of endemic disease; and water, sanitation, and hygiene infrastructure and practices. The site-specific nature - and complexity of transmission - helps explain the observed variation in impacts of water, sanitation, and hygiene interventions. It may also render efforts to estimate or quantify global means for interventions' impacts irrelevant. The theme of this Perspective is that greater reductions in diarrheal disease transmission in LMICs can be achieved by designing interventions to interrupt the most important environmental transmission pathways. Intervention choice should be informed by site-specific conditions, most notably: diarrheal etiology and existing water, sanitation, and hygiene infrastructure and practices. The theme is discussed through the lens of the characteristics of the most important diarrheal diseases (shedding, infectivity, growth, and persistence) and the general characteristics of environmental reservoirs (exposure pathways and fecal contamination). The discussion highlights when interventions - and combinations of interventions - will be most effective at reducing diarrheal disease burden.

Environmental and spatial determinants of enteric pathogen infection in rural Lao People’s Democratic Republic: A cross-sectional study

“…As a result, viral pathogens spread easily from person to person and via fomites [57,60,61]. Evidence suggests that improvements in sanitation alone are not sufficient to prevent enteric virus transmission [62], especially rotavirus which is highly infectious and extremely persistent in the environment [63]. Our results are consistent with research from India which reported an increased risk (though not significantly) of previous viral infection among urban households with toilets [64].…”

Rotavirus and Astrovirus

“…RVA affect children of all social classes, indicating that, unlike other enteric pathogens of fecal-oral transmission, improvements in basic sanitation and hygiene procedures seems to be not sufficient to control the virus infection (Barreto et al, 2006). RVA is persistent in environment and extremely infectious (ID50 is ~ 6 viral units) (Julian, 2016). Therefore, the most effective approach to control RVA infections is by vaccination (Estes & Greenberg, 2013).…”

Synthesis and characterization of microwave‐assisted biologically active triazole silanes

“…Intestinal protozoan parasites are a major global health burden; giardiasis is an important parasitic cause and is accompanied by diarrhea …”

“…Intestinal protozoan parasites [4] are a major global health burden; giardiasis [5] is an important parasitic cause and is accompanied by diarrhea. [6][7][8] According to WHO, this insidious disease is the second-leading cause of death in child mortality and morbidity, a global urgency that cannot be overlooked.…”