Citation:

Egorov, A., S. Griffin, Shay Fout, H. Ward, AND Tim Wade. Application of a salivary immunoassay to assess waterborne Cryptosporidium infections in a prospective community study. Water and Health Conference, Chapel Hill, North Carolina, October 16 - 20, 2017.

Impact/Purpose:

Objectives of this research project were to pilot test a newly developed salivary antibody assay in a field study and to assess potential effects of improved water treatment in compliance with the new EPA surface water treatment rule LT2ESWTR on waterborne transmission of Cryptosporidium. This prospective panel study was conducted before and after the introduction of new water treatment in Lawrence, MA. It is the first study to demonstrate that improved water treatment was associated with a reduction of Cryptosporidium transmission through drinking water in a specific community.

Description:

Background: Salivary antibody is a promising non-invasive biomarker of specific infections. This exploratory study used an in-house salivary immunoassay to assess waterborne transmission of Cryptosporidium. Methods: Families with children were followed during summer-early winter periods in a Massachusetts city using a microbiologically contaminated river as its only source, before and after construction of a new water treatment plant. Monthly saliva samples (7,754 samples from 2,178 individuals) were analyzed for immunoglobulin (Ig) G responses to the recombinant protein gp15 protein of Cryptosporidium hominis using an in-house Luminex immunoassay. Immunoconversion was defined as at least four-fold increase in a ratio of anti-pathogen IgG response and total IgG with post-conversion response above the upper 90% prediction limit of spline function of age. Results: Self-reported gastrointestinal illness during the previous month was associated with 2.9 (95% confidence limits 1.0; 8.5) adjusted odds ratio (aOR) of immunoconversion to Cryptosporidium. Swimming in natural water bodies or chlorinated pools during previous month was associated with 3.7 (1.2; 11.5) and 4.2 (1.4; 13.0) aORs of immunoconversion respectively. Analysis of interaction effect of self-reported non-boiled tap water consumption (dichotomized) and study phase demonstrated that drinking water from the municipal system was associated with 6.5 (1.4; 30.3) lower adjusted odds of Cryptosporidium immunoconversion after the introduction of new water treatment than before it. Conclusion: Improved treatment of drinking water was associated with a significant reduction of transmission of Cryptosporidium through consumption of non-boiled tap water. Disclaimer: This abstract does not necessarily reflect EPA policy.

Record Details: