The association of drinking water treatment and distribution network disturbances with Health Call Centre contacts for gastrointestinal illness symptoms

There are relatively few studies on the association between disturbances in drinking waterservices and symptoms of gastrointestinal (GI) illness. Health Call Centres data concerningGI illness may be a useful source of information. This study investigates if there is anincreased frequency of contacts with the Health Call Centre (HCC) concerning gastrointestinal symptoms at times when there is a risk of impaired water quality due to disturbances at water works or the distribution network. The study was conducted inGothenburg, a Swedish city with 0.5 million inhabitants with a surface water source ofdrinking water and two water works. All HCC contacts due to GI symptoms (diarrhoea,vomiting or abdominal pain) were recorded for a three-year period, including also sex, age,and geocoded location of residence. The number of contacts with the HCC in the affectedgeographical areas were recorded during eight periods of disturbances in the water works(e.g. short stops of chlorine dosing), six periods of large disturbances in the distributionnetwork (e.g. pumping station failure or pipe breaks with major consequences), and 818pipe break and leak repairs over a three-year period. For each period of disturbance theobserved number of calls was compared with the number of calls during a control periodwithout disturbances in the same geographical area. In total about 55, 000 calls to the HCCdue to GI symptoms were recorded over the three-year period, 35 per 1000 inhabitants andyear, but much higher (>200) for childre