208190 Detection of viable Ascaris ova in ecological toilet biosolids in Bolivia

Tuesday, November 10, 2009

Scot Raymond Seitz , Center for Global Safe Water, Rollins School of Public Health, Emory University, Atlanta, GA
Lourdes Echalar , Instituto Boliviano de Biología de Altura, Universidad Mayor de San Andrés, La Paz, Bolivia
Ximena Rodriguez , Instituto Boliviano de Biología de Altura, Universidad Mayor de San Andrés, La Paz, Bolivia
Raul Silveti , Fundacion Sumaj Huasi, La Paz, Bolivia
Oscar Suntura , Fundacion Sumaj Huasi, La Paz, Bolivia
Juan Carlos Suntura , Fundacion Sumaj Huasi, La Paz, Bolivia
Christine L. Moe, PhD , Center for Global Safe Water, Rollins School of Public Health, Emory University, Atlanta, GA
Background: Sanitation in Bolivia needs to be substantially increased in order to meet the UN Millennium Development Goals. Ecological sanitation (EcoSan) is a dry sanitation strategy designed to contain human excreta, inactivate enteric pathogens, and produce agricultural fertilizer. However, EcoSan may facilitate fecal-oral transmission of some pathogens if the biosolids removed from the storage chamber still contain viable pathogens. We examined the viability of Ascaris lumbricoides, a robust enteric pathogen, in fecal biosolids from the storage chamber of double-vault, urine-diverting (DVUD) toilets in Bolivia.

Methods: Biosolids samples were collected from the closed-vault of 38 EcoSan toilets in 7 communities in 3 ecological zones in Bolivia. In addition to measuring pH, moisture content and temperature, the viability of Ascaris ova was determined using an adaptation of the USEPA “Methods for Detection, Enumeration, and Viability Determination of Ascaris Ova in Sludge.”

Results: Of the 38 biosolids samples, 24 (63%) contained Ascaris ova, and there was a greater occurrence of Ascaris ova in the biosolids samples from the valley (79%) and tropical (65%) zones compared to the highlands (29%). Only one Ascaris-positive sample, from the tropical zone, contained inactive Ascaris ova. The average storage time, pH, and temperature of the biosolids samples were 5.9 months, 8.9, and 16.0°C, respectively.

Conclusions: Our results indicate that the DVUD EcoSan toilet designs we evaluated are not effective at inactivating Ascaris ova in Bolivia. Innovative sanitation designs that effectively inactivate Ascaris ova and other pathogens under a range of climate conditions need to be developed.

Learning Objectives:
1) Evaluate the viability of Ascaris ova in ecological toilet biosolids in Bolivia; 2) Compare the viability and occurrence of Ascaris ova in ecological toilet biosolids collected from three different ecological zones in Bolivia.

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: As a research assistant in Christine Moe's laboratory, I lead the organization, implementation, and analysis of this project. In addition, I have researched infectious disease transmission for over 2.5 years. I have a thorough educational background in Biology and I have received several grants to conduct independent research in infectious disease transmission and immunology.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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