The complex association between drinking water consumption and endemic gastrointestinal illness as shown by Swedish cohort studies.

It is well known that municipal drinking water may be the cause of gastrointestinal illness (GII) outbreaks, but it is still unclear to what extent drinking water contributes to endemic GII. To explore this, we conducted a prospective cohort study among 6,955 adults in five municipalities in Sweden, collecting monthly GII episodes and mean daily cold drinking water consumption through SMS (Short Message Service). When the association between drinking water consumption and GII (all symptoms) and acute gastrointestinal illness (AGI, vomiting and/or three loose stools during a 24-h period) were assessed, there were indications that the association departed from linearity, following a unimodal shape.

Bacterial composition in Swedish raw drinking water reveals three major interacting ubiquitous metacommunities.

Background: Surface raw water used as a source for drinking water production is a critical resource, sensitive to contamination. We conducted a study on Swedish raw water sources, aiming to identify mutually co-occurring metacommunities of bacteria, and environmental factors driving such patterns.

Methods: The water sources were different regarding nutrient composition, water quality, and climate characteristics, and displayed various degrees of anthropogenic impact.

Drinking Water Disinfection by-Products and Congenital Malformations: A Nationwide Register-Based Prospective Study.

Background: Drinking water chlorination by-products have been associated with adverse reproductive outcomes, although the findings for congenital malformations are still inconclusive.

Objective: We conducted a nationwide register-based prospective study to assess whether first trimester maternal exposure to the four most common trihalomethanes [total trihalomethanes (TTHM)] via municipal drinking water was associated with risk of congenital malformation among newborns.

Methods: We included all births during 2005-2015 (live and stillbirths) of mothers residing in Swedish localities having inhabitants, two or fewer operating water works, and sufficient municipal TTHM monitoring data.

Exposure to Drinking Water Chlorination by-Products and Fetal Growth and Prematurity: A Nationwide Register-Based Prospective Study.

Background: Chlorination is globally used to produce of safe drinking water. Chlorination by-products are easily formed, and there are indications that these are associated with adverse reproductive outcomes.

Objectives: We conducted a nationwide register-based prospective study to assess whether gestational exposure to the four most common chlorination by-products [total trihalomethanes (TTHMs)] via tap water was associated with risk of small for gestational age (SGA), preterm delivery, and very preterm delivery.

Endemic gastrointestinal illness and change in raw water source and drinking water production - A population-based prospective study.

There are indications that drinking water may contribute to endemic gastrointestinal illness (GII) even when the drinking water quality meets current standards, but the knowledge is limited. In this population-based prospective study, we assessed if changes in municipal drinking water production affected the GII incidence, by collecting self-reported GII episodes among the population in two municipalities during calendar time-specific inter-annual periods. About 2600 adults in central Sweden and 2600 adults (including 700 households with children aged 0-9 years) in Southwest Sweden, were followed during a baseline and a follow-up period in 2012-2016.

Assessment of drinking water quality at the tap using fluorescence spectroscopy.

Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively, inexpensively and potentially on-line via fluorescence and absorbance spectroscopy. Detecting elevated DOM requires potential contamination events to be distinguished from natural fluctuations in the system, but how much natural variation to expect in a stable distribution system is unknown.

Gastrointestinal illness linked to incidents in drinking water distribution networks in Sweden.

During recent years, knowledge gaps on drinking water-related gastrointestinal illness have been identified, especially for non-epidemic cases. Pathogen contamination of drinking water during distribution has been suggested to contribute to these cases, but the risk factors are not yet fully understood. During 2014-2015, we conducted an epidemiological study in five municipalities in Sweden, to assess whether incidents in the drinking water distribution system influence the risk of gastrointestinal illness.

Drinking water consumption patterns among adults-SMS as a novel tool for collection of repeated self-reported water consumption.

Studies have shown that the average drinking water consumption ranges between 0.075 and 3 L/day for adults with both national and regional differences. For exposure assessment of drinking water hazards, country-specific drinking water consumption data including sources of the consumed water may therefore be warranted.

Measuring sporadic gastrointestinal illness associated with drinking water - an overview of methodologies.

There is an increasing awareness that drinking water contributes to sporadic gastrointestinal illness (GI) in high income countries of the northern hemisphere. A literature search was conducted in order to review: (1) methods used for investigating the effects of public drinking water on GI; (2) evidence of possible dose-response relationship between sporadic GI and drinking water consumption; and (3) association between sporadic GI and factors affecting drinking water quality. Seventy-four articles were selected, key findings and information gaps were identified.

Efficacy of water treatment processes and endemic gastrointestinal illness - A multi-city study in Sweden.

Outbreaks of acute gastrointestinal illnesses (AGI) have been linked to insufficient drinking water treatment on numerous occasions in the industrialized world, but it is largely unknown to what extent public drinking water influences the endemic level of AGI. This paper aimed to examine endemic AGI and the relationship with pathogen elimination efficacy in public drinking water treatment processes. For this reason, time series data of all telephone calls to the Swedish National Healthcare Guide between November 2007 and February 2014 from twenty Swedish cities were obtained.

Public health burden due to infections by verocytotoxin-producing Escherichia coli (VTEC) and Campylobacter spp. as estimated by cost of illness and different approaches to model disability-adjusted life years.

Aims: To estimate disability-adjusted life years (DALY) and cost of illness (COI) associated with the gastrointestinal bacterial pathogens Campylobacter and verocytotoxin-producing Escherichia coli (VTEC) in Sweden and to investigate the impact of variability in health outcomes, data availability, and different assumptions about underreporting on DALY.

Methods: Data from the Swedish notification system, public databases, and the literature were used to estimate COI and DALY. DALY was modelled using a deterministic and a stochastic approach, the latter describing variation in health outcomes between individuals.

Modeling gene associations for virulence classification of verocytotoxin-producing E. coli (VTEC) from patients and beef.

An evaluation of 22 EHEC genes was carried out for virulence classification of VTEC. The data consisted of 116 patient isolates and 42 beef isolates. The symptoms among patients ranged from mild (diarrhea) to severe (bloody diarrhea and HUS).

Influence of arbuscular mycorrhizal mycelial exudates on soil bacterial growth and community structure.

Plant root systems colonized by arbuscular mycorrhizal (AM) fungi have previously been shown to influence soil bacterial populations; however, the direct influence of the AM extraradical mycelium itself on bacterial growth and community composition is not well understood. In this study, we investigated the effects of exudates produced by AM extraradical mycelia on the growth and development of an extracted soil bacterial community in vitro. The chemical composition of the mycelial exudates was analysed using proton nuclear magnetic resonance spectrometry.

Species composition of an ectomycorrhizal fungal community along a local nutrient gradient in a boreal forest.

Soil abiotic factors are considered to be important in determining the distribution of ectomycorrhizal (ECM) fungal species; however, there are few field data to support this. Here, we relate ECM species distributions to changes in soil chemistry along a short (90-m), natural nutrient gradient. The ECM community was characterized, using morphological and molecular techniques, in soil samples collected at 10-m intervals.

Attachment of different soil bacteria to arbuscular mycorrhizal fungal extraradical hyphae is determined by hyphal vitality and fungal species.

Attachment of certain bacteria to living arbuscular mycorrhizal fungal extraradical hyphae may be an important prerequisite for interactions between these microorganisms, with implications for nutrient supply and plant health. The attachment of five different strains of gfp-tagged soil bacteria (Paenibacillus brasilensis PB177 (pnf8), Bacillus cereus VA1 (pnf8), Pseudomonas fluorescens SBW25 :: gfp/lux, Arthrobacter chlorophenolicus A6G, and Paenibacillus peoriae BD62 (pnf8)) to vital and nonvital extraradical hyphae of the arbuscular mycorrhizal fungi Glomus sp. MUCL 43205 and Glomus intraradices MUCL 43194 was examined.