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Application of a salivary immunoassay in a prospective community study of waterborne infections
Citation:
Egorov, A., S. Griffin, H. Ward, K. Reilly, G. Fout, AND Tim Wade. Application of a salivary immunoassay in a prospective community study of waterborne infections. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 142:289-300, (2018). https://doi.org/10.1016/j.watres.2018.05.030
Impact/Purpose:
This research project was conducted under the ORD Accountability initiative intended to demonstrate health benefits of EPA regulations in specific communities. This project applied a newly developed multiplexed salivary antibody assay in a prospective community study of Cryptosporidium and noroivirus before and after the introduction of improved drinking water treatment in Lawrence, MA. The new water treatment plant was designed to comply with the new EPA surface water treatment rule LT2ESWTR. The result showed that an effect of non-boiled tap water consumption on Cryptosporidium infections declined significantly in the 2nd phase of the study. Swimming in public pools and local surface water bodies were also risk factors for Cryptosporidium infections.
Description:
Quantifying sporadic waterborne infections in community settings can be challenging. Salivary antibody immunoassays are a promising non-invasive tool that can be used in prospective studies of common infections, especially those involving children. This study was conducted in a Massachusetts city, which uses a microbiologically contaminated river as its water source, during summer-early winter periods before and after construction of a new drinking water treatment plant. Monthly saliva samples (7,480 samples from 1,170 children and 816 adults) were analyzed for immunoglobulin G (IgG) responses to recombinant proteins of Cryptosporidium, one genogroup I (GI) and two GII noroviruses. Immunoconversion was defined as at least four-fold increase in specific antibody responses between two monthly samples with a post-conversion response above a flexible age-dependent cut-off. Episodes of gastroenteritis (diarrhea or vomiting or cramps) were associated with 3.2 (95% confidence limits 1.1; 9.5) adjusted odds ratio (aOR) of immunoconversion to Cryptosporidium; episodes of combined diarrhea and vomiting symptoms were associated with 3.5 (0.8; 15.0) and 4.6 (1.7; 12.6) aORs of an immunoconversion to GI and GII noroviruses respectively. Swimming in natural water bodies or chlorinated pools was associated with 2.3 (0.4; 15.4) and 4.9 (1.6; 15.5) aORs of immunoconversion to Cryptosporidium, respectively. In a subset of study participants who did not use home water filters, consumption of at least some amount of non-boiled tap water reported in a monthly recall survey was associated with 11.1 (1.2; 100.0) and 0.6 (0.1; 2.5) aORs of immunoconversion to Cryptosporidium before and after the new water treatment plant construction, respectively. Among individuals who used home water filters, associations between non-boiled tap water consumption and Cryptosporidium immunoconversion were not significant before and after new plant construction with aORs of 0.8 (0.2; 3.3) and 0.3 (0.1; 1.6), respectively. The interaction effect of study phase and non-boiled tap water consumption on Cryptosporidium immunoconversions was statistically significant in the entire study population with aOR of 5.4 (1.1; 25.6). This was the first study that has used a salivary antibody immunoassay to demonstrate significant associations between gastrointestinal symptoms and Cryptosporidium and norovirus infections, and between water-related exposures and Cryptosporidium infections.
URLs/Downloads:
DOI: Application of a salivary immunoassay in a prospective community study of waterborne infections