Hindsight Is 20/20: Using History to Avoid Waterborne Disease Outbreaks

Abstract

Despite strenuous efforts to prevent them, waterborne disease outbreaks continue to occur from time to time in countries that have the knowledge and capability to prevent them. This article presents the concept that multiple adverse events or changes can often be associated with waterborne disease outbreaks. The information in this article is designed to encourage water treatment plant operators, water quality supervisors, and plant managers to maintain vigilance at all times so circumstances that might lead to a treatment failure and a disease outbreak can be avoided. The authors discuss the importance of water treatment plant personnel being alert at all times and remaining watchful for changes in source water quality, changes in treated water quality, or both to help minimize the likelihood of future waterborne disease outbreaks.

Published Case Studies of Waterborne Disease Outbreaks—Evidence of a Recurrent Threat

“…Conditions that create a pathogen challenge to the treatment process are often event‐driven (e.g., extreme weather and unusual operating conditions), meaning that such events should be recognized as potential triggers of trouble ( Rose et al, 2000 ). Multiple failures in a system typically must combine for disaster to occur, particularly as more barriers are made effective in seeking higher degrees of safety ( Logsdon et al, 2004 ). This reality also means that one or more barriers can fail or be ineffective without allowing an outbreak to occur, making the independent evaluation of treatment performance by measures such as turbidity or chlorine residual monitoring a necessary activity to assure that sufficient barriers remain intact.…”

“…Craun et al (2003) reviewed outbreaks in the United States from 1991 to 1998 providing extensive categorization of outbreaks into types and by cause. Logsdon et al (2004) considered the extensive literature on waterborne outbreaks and illustrated, with eight case studies, some of the recurring causes, including the alignment of multiple causal factors leading to an outbreak.…”

Development of a Water Quality Index (WQI) of an Artificial Aquatic Ecosystem in Mexico

“…However, from Figure 2(a) it is evident that values were higher in July and August, which may affect the physiology of some aquatic organisms [44]. Logsdon et al [52], Horvatincic et al [53] and Srivastava et al [17] have all noted that precipitation events increase pH levels in aquatic ecosystems due to the runoff of alkaline substances. On the other hand, low pH levels were noted in December (Figure 2(a)), which can be explained by the absence of agricultural activities in the region as well as reduced flows of water.…”

Drinking-water safety – challenges for community-managed systems

“…Rose et al (2000) also conducted a review of waterborne disease outbreaks and climate in the United States for the years 1971-1994. Outbreak occurrence was associated with months having total precipitation ranked in the highest 10%, highest 5% and highest 2.5% of monthly totals, or the months following those with high precipitation (Logsdon et al 2004). For surface water sources, the percentage of outbreaks occurring during the months in the highest 10% of precipitation totals, according to season, ranged from 25% in winter to 40% in spring and autumn.…”

“…The risk of heavy rainfall or snowmelt, and the associated runoff, is that they are key factors in the transportation of pathogenic microorganisms and can lead to a marked decline in water quality (Hunter 2003;Logsdon et al 2004). Another waterborne disease outbreak of cryptosporidiosis occurred in Northwest London and West Hertfordshire, UK in 1997 under similar conditions.…”