Exposure to sewage water and the development of allergic manifestations in Finnish children.

BACKGROUND: The hygiene hypothesis suggests that a decreased microbial load contributes to an increased risk of allergies. In the Finnish municipality of Nokia, sewage water was accidentally mixed with drinking water for 2 days. We studied the association between exposure and the emergence of allergies in children. METHODS: Children aged 2-5 years living in the accident area and an age-matched cohort from the control municipality were recruited. Based on the questionnaires, we identified 139 children exposed to the contaminated water and selected age- and sex-matched controls for them (mean age 16.59 months at the time of the accident). Allergic symptoms and diseases were recorded by ISAAC questionnaires and skin prick tests (SPTs) performed 2 and 5 years after the accident. RESULTS: SPT positivity at 5 years of follow-up was decreased in the children exposed to the sewage water below 1 year of age (OR 0.311, 95% CI 0.118-0.820; P = 0.019), particularly in children who did not develop gastroenteritis at exposure. In contrast, the children over 1 year of age at the exposure tended more likely to be SPT-positive at 5 years of follow-up (OR 1.997, 95% CI 0.963-4.143; P = 0.070). CONCLUSIONS: Sewage water exposure during the first year of life, but not later, decreased the risk of IgE sensitization emphasizing the importance of age as a modulator. The modulation of IgE sensitization by the presence of clinical gastroenteritis at the exposure suggests that the nature of microbial load may have importance or alternatively shared host defense mechanisms protect from infection and atopic sensitization.

Excess healthcare costs of a large waterborne outbreak in Finland.

BACKGROUND: The economic effects of waterborne outbreaks have rarely been reported. A large waterborne outbreak occurred in the town of Nokia in Finland in 2007 with half of the population in the contaminated area suffering from gastroenteritis. We studied the healthcare costs of this outbreak. METHODS: Healthcare costs were studied using register data from the Nokia Health Care Centre, data collected in the regional university hospital, and data from laboratory register on stool samples. RESULTS: Total excess healthcare costs were EUR 354,496, which is approximately EUR 10 per resident of Nokia. There were 2052 excess visits because of gastroenteritis in Nokia Health Care Centre, 403 excess episodes in the university hospital, and altogether over 2000 excess stool samples due to the outbreak. Care in the Nokia Health Care Centre accounted for 44% and care in the university hospital for 42% of the excess healthcare costs while stool samples accounted for only 10%. CONCLUSIONS: Despite the high morbidity, the total cost was low because most patients had a relatively mild illness. The situation would have been worse if the microbes involved had been more hazardous or if the financial situation of the community had been worse. Prevention of waterborne outbreaks is important, as there is a risk of severe short- and long-term health effects and substantial health-economic costs.

Joint symptoms after a large waterborne gastroenteritis outbreak--a controlled, population-based questionnaire study.

OBJECTIVES: Waterborne outbreaks offer an opportunity to study joint symptoms after a simultaneous exposure. In November 2007, a gastroenteritis outbreak due to faecal contamination of tap water took place in a Finnish town. The purpose of this study was to evaluate the occurrence of joint symptoms after the outbreak. METHODS: The authors conducted a controlled, population-based questionnaire survey to study the occurrence of joint symptoms within 8 weeks after the exposure. The survey covered three areas: contaminated and uncontaminated parts of the town and a control town. A total of 1000 residents were randomly selected from each area, and the joint symptoms were first analysed separately and thereafter categorized as arthritis-like if joint swelling, redness, warmth or pain in movement was reported. RESULTS: A total of 2123 responses could be evaluated. The overall prevalence of joint symptoms was 13.9% in the contaminated group, 4.3% in the uncontaminated group and 1.5% among the control group, and the frequency of arthritis-like symptoms in the groups was 6.7, 2.1 and 0.5%, respectively. Gastrointestinal symptoms predicted joint complaints, diarrhoea and blood in faeces being the most significant. Residing in the contaminated area was associated with any joint symptom [odds ratio (OR) = 4.0, 95% CI 1.8, 9.0] and joint pain (OR = 7.3, 95% CI 2.1, 24.8) without preceding gastroenteritis. CONCLUSION: The frequency of joint symptoms was high in the contaminated group and also increased in the uncontaminated group. Furthermore, the risk of joint symptoms was increased in the contaminated group even without gastroenteritis.

The duration of gastrointestinal and joint symptoms after a large waterborne outbreak of gastroenteritis in Finland in 2007--a questionnaire-based 15-month follow-up study.

An extensive drinking water-associated gastroenteritis outbreak took place in the town of Nokia in Southern Finland in 2007. 53% of the exposed came down with gastroenteritis and 7% had arthritis-like symptoms (joint swelling, redness, warmth or pain in movement) according to a population-based questionnaire study at 8 weeks after the incident. Campylobacter and norovirus were the main pathogens. A follow-up questionnaire study was carried out 15 months after the outbreak to evaluate the duration of gastrointestinal and joint symptoms. 323 residents of the original contaminated area were included. The response rate was 53%. Participants were inquired about having gastroenteritis during the outbreak and the duration of symptoms. Of those with gastroenteritis, 43% reported loose stools and abdominal pain or distension after the acute disease. The prevalence of symptoms declined promptly during the first 3 months but at 15 months, 11% reported continuing symptoms. 32% of the respondents with gastroenteritis reported subsequent arthritis-like symptoms. The disappearance of arthritis-like symptoms was more gradual and they levelled off only after 5 months. 19% showed symptoms at 15 months. Prolonged gastrointestinal symptoms correlated to prolonged arthritis-like symptoms. High proportion of respondents continued to have arthritis-like symptoms at 15 months after the epidemic. The gastrointestinal symptoms, instead, had declined to a low level.