Detection and Inactivation of Helminth eggs

Detection and Inactivation of Helminth eggs

Microscope image of Ascaris egg recovered from wastewater. Under favorable conditions in the environment, the single cell visible in the center matures into an embryo that can infect a new host if the egg is ingested.

About

Helminth infections, caused by intestinal worms, are ubiquitous in regions of the world with poor sanitation and warm, moist climates. It is estimated that over one billion people are infected, especially young children, who can suffer life-long impairment of cognitive development. We have developed detection methods to quantify helminth eggs in soil, wastewater, and sludge, using microscopy and PCR, including approaches to distinguish viable from non-viable eggs. Another research area is methods to inactivate Ascaris eggs, which are the most persistent in the environment.

Next Research Area →

Selected Publications

Steinbaum, L., L.H. Kwong, A. Ercumen, M.S. Negash, A.J. Lovely, S.M. Njenga, A.B. Boehm, A.J. Pickering, and K.L. Nelson. (2017) “Detecting and Enumerating Soil-Transmitted Helminth Eggs in Soil: New Method Development and Results from Field Testing in Kenya and Bangladesh.” PLOS Neglected Tropical Diseases 11(4). doi:10.1371/journal.pntd.0005522.

Fidjeland, J., Nordin, A., Pecson, B.M., Nelson, K.L., and B. Vinnerås (2015). ”Modeling the inactivation of Ascaris eggs as a function of ammonia concentration and temperature.” Water Research. 83:153-160.

Raynal, M., Villegas, E.N., and K.L. Nelson (2012). “Enumeration of viable and non-viable larvated Ascaris eggs with quantitative PCR.” Journal of Water and Health. 10(4):594-604.

Pecson, B.M., J.A. Barrios, B.E. Jimenez, and K.L. Nelson. (2007). “The effects of temperature, pH, and ammonia concentration on the inactivation of Ascaris eggs in sewage sludge.” Water Research, 41:2893-2902.

Pecson, B.M., J.A. Barrios, D.R. Johnson, and K.L. Nelson. (2006) “A real-time PCR method for quantifying viable Ascaris eggs using the first internally-transcribed spacer region of rDNA”. Applied and Environmental Microbiology, 72(12): 7864-7872.

Brownell, S.A., and K.L. Nelson (2006). “Inactivation of single-celled Ascaris suum eggs by low-pressure ultraviolet radiation.” Applied and Environmental Microbiology, 72(3): 2178-2184.

Pecson, B.M., and K.L. Nelson. (2005). “Inactivation of Ascaris suum eggs by ammonia.” Environmental Science & Technology, 39:7909-7914.

Nelson, K.L. (2003). “Concentrations and inactivation of Ascaris eggs and pathogen indicator organisms in wastewater stabilization pond sludge.” Water Science and Technology, 48(2):89-95.

Nelson, K.L., and J. L. Darby. (2002). “Determination of the inactivation rate of Ascaris eggs in wastewater stabilization pond sludge using dialysis chambers and sludge cores.” Water Environment Research, 74(4):362-369.

Nelson, K.L., and J. L. Darby. (2001). “Inactivation of viable Ascaris eggs by reagents during enumeration.” Applied and Environmental Microbiology, 67(12):5453-5459.