Research article - Peer-reviewed, 2020
Fate of Ascaris at various pH, temperature and moisture levels
Senecal-Smith, Jenna; Nordin, Annika; Vinnerås, BjörnAbstract
Soil-transmitted helminths (STH) are intestinal worms that infect 24% of the world's population. Stopping the spread of STH is difficult, as the eggs are resilient (can withstand high pH) and persistent (can remain viable in soils for several years). To ensure that new sanitation systems can inactivate STH, a better understanding of their resilience is required. This study assessed the inactivation ofAscariseggs under various conditions, in terms of moisture content (MC) (90%), temperature (20-50 degrees C) and pH (7-12.5). The results highlight that the exposure ofAscariseggs to elevated pH (10.5-12.5) at temperatures <= 27.5 degrees C for >70 days had no effect on egg viability. Compounding effects of alkaline pH (>= 10.5) or decreasing MC (<20%) was observed at 35 degrees C, with pH having more of an effect than decreasing MC. To accelerate the inactivation of STH, an increase in the treatment temperature is more effective than pH increase. Alkaline pH alone did not inactivate the eggs but can enhance the effect of ammonia, which is likely to be present in organic wastes.Keywords
disease transmission; helminths; nutrient recycling; sanitisation; STHPublished in
Journal of Water and Health2020, volume: 18, number: 3, pages: 375-382
Authors' information
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
UKÄ Subject classification
Public Health, Global Health, Social Medicine and Epidemiology
Soil Science
Publication Identifiers
DOI: https://doi.org/10.2166/wh.2020.264
URI (permanent link to this page)
https://res.slu.se/id/publ/105755