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Tim Wade   Dr.  Senior Scientist or Principal Investigator 
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Tim Wade published an article in October 2018.
Top co-authors See all
X. Chris Le

286 shared publications

Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2G3, Canada

Quanlin Li

52 shared publications

Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, CA, United States

Charles Poole

51 shared publications

Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, USA

Richard A Haugland

42 shared publications

U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH, USA

Andrew J. Ghio

40 shared publications

The National Health and Environmental Effects Research Laboratory, Environmental Protection Agency, Chapel Hill, NC, USA

Publication Record
Distribution of Articles published per year 
(2010 - 2018)
Total number of journals
published in
Publications See all
Article 0 Reads 1 Citation Application of a salivary immunoassay in a prospective community study of waterborne infections Andrey I. Egorov, Shannon M. Griffin, Honorine D. Ward, Kevi... Published: 01 October 2018
Water Research, doi: 10.1016/j.watres.2018.05.030
DOI See at publisher website
Article 0 Reads 0 Citations Environmental risk factors for Toxoplasma gondii infections and the impact of latent infections on allostatic load in re... Andrey I. Egorov, Reagan Converse, Shannon M. Griffin, Jenni... Published: 23 August 2018
BMC Infectious Diseases, doi: 10.1186/s12879-018-3343-y
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Toxoplasma gondii infection can be acquired through ingestion of infectious tissue cysts in undercooked meat or environmental oocysts excreted by cats. This cross-sectional study assessed environmental risk factors for T. gondii infections and an association between latent infections and a measure of physiologic dysregulation known as allostatic load. Serum samples from 206 adults in the Durham-Chapel Hill, North Carolina area were tested for immunoglobulin (IgG) responses to T. gondii using commercial ELISA kits. Allostatic load was estimated as a sum of 15 serum biomarkers of metabolic, neuroendocrine and immune functions dichotomized at distribution-based cutoffs. Vegetated land cover within 500 m of residences was estimated using 1 m resolution data from US EPA’s EnviroAtlas. Handling soil with bare hands at least weekly and currently owning a cat were associated with 5.3 (95% confidence limits 1.4; 20.7) and 10.0 (2.0; 50.6) adjusted odds ratios (aOR) of T. gondii seropositivity, respectively. There was also a significant positive interaction effect of handling soil and owning cats on seropositivity. An interquartile range increase in weighted mean vegetated land cover within 500 m of residence was associated with 3.7 (1.5; 9.1) aOR of T. gondii seropositivity. Greater age and consumption of undercooked pork were other significant predictors of seropositivity. In turn, T. gondii seropositivity was associated with 61% (13%; 130%) greater adjusted mean allostatic load compared to seronegative individuals. In contrast, greater vegetated land cover around residence was associated with significantly reduced allostatic load in both seronegative (p < 0.0001) and seropositive (p = 0.004) individuals. Residents of greener areas may be at a higher risk of acquiring T. gondii infections through inadvertent ingestion of soil contaminated with cat feces. T. gondii infections may partially offset health benefits of exposure to the natural living environment.
Article 6 Reads 1 Citation Asymptomatic norovirus infection associated with swimming at a tropical beach: A prospective cohort study Timothy J. Wade, Swinburne A. J. Augustine, Shannon M. Griff... Published: 28 March 2018
PLOS ONE, doi: 10.1371/journal.pone.0195056
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Swimming in fecally-contaminated waterbodies can result in gastrointestinal infections. However, the pathogenic microorganisms responsible are not well understood because sporadic cases of illness are not reported completely, exposure information is often not collected, and epidemiology studies rely on self-reported symptoms. Noroviruses are considered a likely cause because they are found in high densities in sewage, resistant to wastewater treatment and survive in the environment. In this study, saliva samples were collected from subjects at a beach in Puerto Rico and tested for evidence of norovirus-specific IgG responses as an indicator of incident norovirus infection. Saliva samples were collected from 1298 participants using an oral swab. Samples were collected on the day of the beach visit (S1); after 10–12 days (S2); and after three weeks (S3). Saliva was tested for IgG responses to GI.1 and GII.4 noroviruses using a microsphere based multiplex salivary immunoassay. Immunoconversion was defined as a four-fold increase in median fluorescence intensity (MFI) from S1 to S2 with the S3 sample at least three times above the S1 MFI. Thirty-four subjects (2.6%) immunoconverted to GI.1 or GII.4 norovirus. Swimmers who immersed their head in water had a higher rate of immunoconversion (3.4%), compared to either non-swimmers (0.0%, p = 0.003) or waders and non-swimmers combined (0.4%, Odds Ratio: 5.07, 95% Confidence Interval:1.48–17.00). Immunoconversion was not associated with gastrointestinal symptoms. This is the first study to demonstrate an association between swimming at a beach impacted by fecal contamination and asymptomatic norovirus infection. The findings implicate recreational water as potentially important transmission pathway for norovirus infection.
Article 4 Reads 0 Citations Extreme precipitation and emergency room visits for influenza in Massachusetts: a case-crossover analysis Genee S. Smith, Kyle P. Messier, James L. Crooks, Timothy J.... Published: 17 October 2017
Environmental Health, doi: 10.1186/s12940-017-0312-7
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Influenza peaks during the wintertime in temperate regions and during the annual rainy season in tropical regions – however reasons for the observed differences in disease ecology are poorly understood. We hypothesize that episodes of extreme precipitation also result in increased influenza in the Northeastern United States, but this association is not readily apparent, as no defined ‘rainy season’ occurs. Our objective was to evaluate the association between extreme precipitation (≥ 99th percentile) events and risk of emergency room (ER) visit for influenza in Massachusetts during 2002–2008. A case-crossover analysis of extreme precipitation events and influenza ER visits was conducted using hospital administrative data including patient town of residence, date of visit, age, sex, and associated diagnostic codes. Daily precipitation estimates were generated for each town based upon data from the National Oceanic and Atmospheric Administration. Odds ratio (OR) and 95% confidence intervals (CI) for associations between extreme precipitation and ER visits for influenza were estimated using conditional logistic regression. Extreme precipitation events were associated with an OR = 1.23 (95%CI: 1.16, 1.30) for ER visits for influenza at lag days 0–6. There was significant effect modification by race, with the strongest association observed among Blacks (OR = 1.48 (1.30, 1.68)). We observed a positive association between extreme precipitation events and ER visits for influenza, particularly among Blacks. Our results suggest that influenza is associated with extreme precipitation in a temperate area; this association could be a result of disease ecology, behavioral changes such as indoor crowding, or both. Extreme precipitation events are expected to increase in the Northeastern United States as climate change progresses. Additional research exploring the basis of this association can inform potential interventions for extreme weather events and influenza transmission.
Article 3 Reads 1 Citation Exposure to human-associated fecal indicators and self-reported illness among swimmers at recreational beaches: a cohort... Melanie D. Napier, Richard Haugland, Charles Poole, Alfred P... Published: 02 October 2017
Environmental Health, doi: 10.1186/s12940-017-0308-3
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Fecal indicator bacteria used to assess illness risks in recreational waters (e.g., Escherichia coli, Enterococci) cannot discriminate among pollution sources. To address this limitation, human-associated Bacteroides markers have been proposed, but the risk of illness associated with the presence of these markers in recreational waters is unclear. Our objective was to estimate associations between human-associated Bacteroides markers in water and self-reported illness among swimmers at 6 U.S. beaches spanning 2003–2007. We used data from a prospectively-enrolled cohort of 12,060 swimmers surveyed about beach activities and water exposure on the day of their beach visit. Ten to twelve days later, participants reported gastroinestinal, diarrheal, and respiratory illnesses experienced since the visit. Daily water samples were analyzed for the presence of human-associated Bacteroides genetic markers: HF183, BsteriF1, BuniF2, HumM2. We used model-based standardization to estimate risk differences (RD) and 95% confidence intervals (CI). We assessed whether the presence of Bacteroides markers were modifiers of the association between general Enterococcus and illness among swimmers using interaction contrast. Overall we observed inconsistent associations between the presence of Bacteroides markers and illness. There was a pattern of increased risks of gastrointestinal (RD = 1.9%; 95% CI: 0.1%, 3.7%), diarrheal (RD = 1.3%; 95% CI: -0.2%, 2.7%), and respiratory illnesses (RD = 1.1%; 95% CI: -0.2%, 2.5%) associated with BsteriF1. There was no evidence that Bacteroides markers acted as modifiers of Enterococcus and illness. Patterns were similar when stratified by water matrix. Quantitative measures of fecal pollution using Bacteroides, rather than presence-absence indicators, may be necessary to accurately assess human risk specific to the presence of human fecal pollution. The online version of this article (10.1186/s12940-017-0308-3) contains supplementary material, which is available to authorized users.
Article 6 Reads 4 Citations Vegetated Land Cover Near Residence is Associated with Reduced Allostatic Load and Improved Biomarkers of Neuroendocrine... Andrey I. Egorov, Shannon M. Griffin, Reagan R. Converse, Je... Published: 11 July 2017
Environmental Research, doi: 10.1016/j.envres.2017.07.009
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Greater exposure to urban green spaces has been linked to reduced risks of depression, cardiovascular disease, diabetes and premature death. Alleviation of chronic stress is a hypothesized pathway to improved health. Previous studies linked chronic stress with a biomarker-based composite measure of physiological dysregulation known as allostatic load. This study’s objective was to assess the relationship between vegetated land cover near residences and allostatic load. This cross-sectional population-based study involved 206 adult residents of the Durham-Chapel Hill, North Carolina metropolitan area. Exposure was quantified using high-resolution metrics of trees and herbaceous vegetation within 500 m of each residence derived from the U.S. Environmental Protection Agency’s EnviroAtlas land cover dataset. Eighteen biomarkers of immune, neuroendocrine, and metabolic functions were measured in serum or saliva samples. Allostatic load was defined as a sum of potentially unhealthy biomarker values dichotomized at 10th or 90th percentile of sample distribution. Regression analysis was conducted using generalized additive models with two-dimensional spline smoothing function of geographic coordinates, weighted measures of vegetated land cover allowing decay of effects with distance, and geographic and demographic covariates. An inter-quartile range increase in distance-weighted vegetated land cover was associated with 37% (95% Confidence Limits 46%; 27%) reduced allostatic load; significantly reduced adjusted odds of having low level of norepinephrine, dopamine, and dehydroepiandrosterone, and high level of epinephrine, fibrinogen, vascular cell adhesion molecule-1, and interleukin-8 in serum, and α-amylase in saliva; and reduced odds of previously diagnosed depression. The observed effects of vegetated land cover on allostatic load and individual biomarkers are consistent with prevention of depression, cardiovascular disease and premature mortality.