Water outage increases the risk of gastroenteritis and eyes and skin diseases

Water supply is essential to the maintenance of proper sanitation and personal hygiene. Inadequate water supply increases the risks of diarrhea, other infectious diseases, and related complaints. Natural disasters, such as floods or droughts, contribute to inadequate water supply and may lead to the outbreak of water-borne and water-washed diseases, including gastroenteritis and respiratory tract and skin infections [1-7.] Huge diarrhea outbreaks cause cholera and Escherichia coli infections after a flood [8, 9]. The diarrhea outbreak in Milwaukee, which was caused by cryptosporidium oocysts and which affected 403,000 victims, was caused by a filtration system that malfunctioned after a heavy storm [10–12]. The risk of waterborne gastrointestinal illness also has been associated with drinking water turbidity under current water treatment practices even without heavy precipitation [13, 14].

Water outage is another public and personal hygiene concern because it means the lack of water for use in laundry, kitchen, and restroom maintenance. Water outage following a power outage has always been a major problem in communities and in hospitals. Inadequate water services for home usage increased the risks of pneumonia and influenza infections among families in rural Alaska [15]. Surprisingly, information on diseases related to water supply shortage has not been well investigated and reported in short-term water outages in communities. This is certainly a drawback in the prevention of diseases because of the lack of water.

Taiwan is an island located in the western part of the Pacific Ocean that frequently receives undistributed rainfall. In fact, water treatment plants may shut down if water turbidity resulting from heavy precipitation during typhoons is too high to treat. Water outage may also occur for other reasons, such as during constructions or when water supply pipes are broken. No information has been reported on health effects during water outage intervals. Therefore, we used water supply records, weather monitoring data, and national insurance claims to assess whether or not water outages caused by constructions or broken water supply pipes lead to increased incidences of infectious diseases. We placed particular focus on gastroenteritis and skin and eye complaints.

Public water supply rates of the areas studied ranged from 77.05%-99.59% (average of 92.73%). In all, there were 193 island-wide water outages in 2004-2006, and 168 events (112 caused by broken pipes and 56 caused by constructions) occurred in the study areas. The average duration of water outages was 15.7 (95% CI 6.7-36.3) hours for these areas.

To the best of our knowledge, this is the first study that provides information on gastroenteritis and on complaints related to skin and eye diseases during and after water outages for the population of a subtropical island. We found that incidences of gastroenteritis, skin diseases, and eye diseases among outpatient visits are higher during water outage periods than during normal periods. Medical services are availed of relatively more for gastroenteritis and skin infections than for eye infections, including both outpatient visits and measures of EICC.

Water outages were usually short, with an average of 15.7 (95% CI 6.7-36.3) hours. However, they still caused a significant effect on personal hygiene in the communities affected. Our observations revealed that medical service utilization for these diseases during water outages was approximately elevated from 23% to 48% among age groups compared with that during normal water supply periods.

Several studies have reported an association between heavy precipitation and water-borne diseases [1, 10–12, 16]. Although the people in Taiwan have experienced many floods before, they have not yet experienced a cryptosporidiosis outbreak, such as that which occurred in Milwaukee [12]. This difference may have to do with water utilization behavior, given that the people in Taiwan are used to drinking boiled water. Boiling contaminated water during water outages makes it safe to drink. However, people may still become infected when unboiled contaminated water containing microorganisms come into contact with food, the eyes and cuts on the skin. People may have to wash less often and because of water scarcity. Coincidentally, inadequate personal hygiene practices could increase potential risks for gastrointestinal disorders, and skin and eye infections or allergies. In the present study, we clarified this pathway of infection by analyzing the water supply quality reported during the study periods. No significant differences were found. Hence, we believe that the lack of water access is the main cause of increased occurrences of infectious diseases associated with water shortages in Taiwan.

The present study further examined whether risks of infections were associated with water quality. Water quality test results showed that the unqualified rates were alike during water outages and lag periods, but were slightly higher than the normal period (0.7% vs. 0.2%, p = 0.31). Although this difference is not statistically significant, the effects of outages still lead to higher infection risks. Turbidity threshold for action, if any, should perhaps be questioned.

In the present study, we also found that the risks of skin and eye diseases, and gastroenteritis increases as temperature increases during water outages (Table 3). This demonstrates a dose-response relationship between increased contact with microorganisms and temperatures, i.e., when it is warmer, there is greater risk of contracting infections. Pathogens are generally associated with temperature [17]. The effects of temperature on gastroenteritis vary among countries and between seasons because temperature acts on both medical search and exposure routes. Checkley et al. found that, in Peruvian children, the RR of daily hospital admissions for diarrheal diseases ranges from 1.04-1.12 as ambient temperature increases to 1°C. Hashizume et al. also found a linear association between daily non-cholera diarrhea and average temperature increase in Bangladesh [18]. Even the seasonality of enterovirus isolation is observed in both clinical cases [19, 20] and environmental water samples, which are higher during warmer months [19–23]. The weather in Norway is much colder than in Taiwan. Nygård et al. found that households exposed to breaks and maintenance works in the water distribution system are 1.58-fold more likely to suffer from gastrointestinal illnesses than unexposed households [24].

Aside from public water supply, the usage of underground and well water may increase risks of infections. For instance, the outbreak of E. coli O157:H7 in New York in 1999 was linked to contaminated well water [23]. Curriero et al. reviewed 548 water-borne disease outbreaks and found that 36% of such outbreaks were caused by underground water contamination associated with extreme precipitation [1]. However, approximately only 8.4% of the population in Taiwan used water sources other than the public water supply, and most of them resided in suburban areas (3.8%). This was a minor part in our study areas. Thus, we were unable to determine whether people using underground or well water suffered from increased infection risks as well. The other limitation of our study is the fact that some patients may not seek health care and, thus, may not file insurance claims. However, the underestimated case pattern should not be significantly different between normal water supply days and outage days.

The strength of the present study is the fact that the daily data of both water supply records and weather monitoring results were available and can be linked to the reimbursement claims data on health insurance. The claims data reduced self-reported bias, making it possible to observe individuals who were more likely affected by water outages. With daily average temperatures linked to incidences of diseases, observing the effects of weather on the relationship between water outages and the use of medical services is also possible. To the best of our knowledge, this is the first study that provides a link to the aforementioned data sets.

The present study demonstrates that a short water outage may increase risks of gastroenteritis and infections of the eyes and skin. These results also demonstrate that infection prevention measures should be heightened during warm days. In Taiwan, almost all buildings and households are equipped with water storage facilities. Water supply companies should inform the community in advance before any water-related construction is conducted and urge residents to fill their storage facilities with enough water. In case of broken pipes, water supply companies are obliged to traffic enough water to an affected community. Residents should be informed in advance as to where they can procure safe water for drinking, cooking, and personal hygiene use, including bottled, boiled, or treated water. At the same time, the local health department should make specific recommendations for boiling or treating water in areas affected by water outages.