The prevalence of gastrointestinal and arthritis-like symptoms in the contaminated group within fifteen months from the outbreak.

<p>The proportions were counted as dividing the number of subjects with symptoms by the number of subjects having fallen ill with gastroenteritis at the time of the outbreak (N = 174). The curves represent the proportion of subjects with symptoms and the vertical lines are the 95% confident intervals.</p

The prevalence of arthritis-like symptoms among participants with and without gastrointestinal symptoms (loose stools and abdominal pain or distension) at 3 and 15 months after the water contamination.

<p>The prevalence of arthritis-like symptoms among participants with and without gastrointestinal symptoms (loose stools and abdominal pain or distension) at 3 and 15 months after the water contamination.</p

a–b. Monthly incidence (/10 000 inhabitants) of microbiological stool specimens (Fig. 2a) and positive findings (Fig. 2b).

<p>Black bars represent the town of Nokia and white bars the control municipality. The arrows indicate the outbreak month, December 2007. Only findings of <i>Campylobacter</i> and <i>Giardia</i> from January 2007 to December 2009 were counted.</p

Evolution of the study groups in the follow-up study.

<p>Study groups were based on the original population samples that were used in the first survey. The study groups became step-wise smaller because of lack of response to the first survey, denying further contact, and lack of response to the follow-up survey.</p

Categorized distance and proportion of cases within those groups in a waterborne outbreak in Vuorela, July 2012.

<p>Categorized distance and proportion of cases within those groups in a waterborne outbreak in Vuorela, July 2012.</p

The Univariate and multivariate results for individual risk factors and the generalized additive model risk ratios with the spatial term of a waterborne outbreak in Vuorela, July 2012.

<p>The Univariate and multivariate results for individual risk factors and the generalized additive model risk ratios with the spatial term of a waterborne outbreak in Vuorela, July 2012.</p

Epidemic curve of a waterborne outbreak in Vuorela, July 2012 based on the reported onset date of illness of the cases, and <i>E. coli</i> bacteria counts and chlorine levels in the point 7 (See Fig. 1) of the water distribution network.

<p>Epidemic curve of a waterborne outbreak in Vuorela, July 2012 based on the reported onset date of illness of the cases, and <i>E. coli</i> bacteria counts and chlorine levels in the point 7 (See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104713#pone-0104713-g001" target="_blank">Fig. 1</a>) of the water distribution network.</p

Microbiological results of faecal samples from symptomatic patients of a waterborne outbreak in Vuorela, July 2012.

<p>Methods used were cultivation¹, PCR/RT-PCR² (polymerase chain reaction/reverse transcripition-PCR), EM³ (electron microscopy) and/or EIA⁴ (Enzyme Immunoassay). ⁵<i>Campylobacter jejuni</i> and ⁶EHEC O157:H7 (from one sample) and ⁷sapovirus GII.P3 were isolated from the samples.</p

Phylogenetic relationships among OTUs (•) of the genus <i>Arcobacter</i> in a waterborne outbreak in Vuorela, July 2012.

<p>The tree was inferred from a maximum likelihood analysis of aligned 16S rRNA gene sequence (≈255 bp) and nodes with a bootstrap value ≥50% of 1 000 replicates are identified. <i>Sulfurospirillum deleyianum</i> (NR_074378) and <i>Campylobacter fetus</i> (L04314) were used as outgroup. Number in bracket represents the total amount of DNA/RNA reads identified in samples from A) the upper storage reservoir before cleaning, B) tap water during contamination and C) the upper storage reservoir after cleaning. *<i>A. butzleri</i>, <i>A. cryaerophilus</i> and <i>A. skirrowii</i> have been associated with gastrointestinal diseases <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104713#pone.0104713-Collado1" target="_blank">[76]</a>.</p