Application of a salivary immunoassay in a prospective community study of waterborne infections. (1st October 2018)

• Record Type: Journal Article
• Authors: Egorov, Andrey I.; Griffin, Shannon M.; Ward, Honorine D.; Reilly, Kevin; Fout, G. Shay; Wade, Timothy J.
• Is Part Of: Water research. Volume 142(2018)
• Page Start: 289
• Page End: 300
• Publication Date: 2018-10-01
• Subjects: Waterborne infections -- Cryptosporidium -- Noroviruses -- Immunoassay -- Prospective study; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2018.05.030
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: 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 (7480 samples from 1170 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. Highlights: Antibodies in saliva were measured to detect immunoconversions in a community study. Episodes of diarrhea and vomiting were linked with immunoconversions to noroviruses. Episodes of gastroenteritis were linked with immunoconversions to Cryptosporidium . Swimming in pools was linked with immunoconversions to Cryptosporidium . Improved drinking water treatment is linked with reduced Cryptosporidium infections.