Escherichia coli: the best biological drinking water indicator for public health protection.

Public health protection requires an indicator of fecal pollution. It is not necessary to analyse drinking water for all pathogens. Escherichia coli is found in all mammal faeces at concentrations of 10 log 9(-1), but it does not multiply appreciably in the environment. In the 1890s, it was chosen as the biological indicator of water treatment safety. Because of method deficiencies, E. coli surrogates such as the 'fecal coliform' and total coliforms tests were developed and became part of drinking water regulations. With the advent of the Defined Substrate Technology in the late 1980s, it became possible to analyse drinking water directly for E. coli (and, simultaneously, total coliforms) inexpensively and simply. Accordingly, E. coli was re-inserted in the drinking water regulations. E. coli survives in drinking water for between 4 and 12 weeks, depending on environmental conditions (temperature, microflora, etc.). Bacteria and viruses are approximately equally oxidant-sensitive, but parasites are less so. Under the conditions in distribution systems, E. coli will be much more long-lived. Therefore, under most circumstances it is possible to design a monitoring program that permits public health protection at a modest cost. Drinking water regulations currently require infrequent monitoring which may not adequately detect intermittent contamination events; however, it is cost-effective to markedly increase testing with E. coli to better protect the public's health. Comparison with other practical candidate fecal indicators shows that E. coli is far superior overall.

Health risks from contaminated water: do class and race matter?

The impact of contaminants in water on minorities and economically disadvantaged persons was reviewed. Environmental legislation governing water was summarized as background information against which relevant studies were evaluated. The majority of the available information was anecdotal or case study and did not lend itself to making quantitative comparisons or analyses. However, the data did present certain trends that led to the conclusion that inequities concerning exposure to contaminants in water may exist. The following recommendations were made: current data bases should be analyzed and new data bases created to facilitate assessments of exposure to waterborne contaminants to all populations; an analysis of populations not covered by the Safe Drinking Water Act should be undertaken; a survey should be conducted of the drinking water infrastructure and the results evaluated to identify any impacts to minorities and economically disadvantaged persons; the social, cultural and economic characteristics that influence human exposure to waterborne contaminants need to be identified; and better educational and community outreach programs need to be developed and implemented.

Waterborne disease in Colorado: three years' surveillance and 18 outbreaks.

The Colorado Department of Health conducted intensive surveillance for waterborne diseases during the three-year period July 1, 1980-June 30, 1983. Eighteen outbreaks of waterborne illness were investigated. Outbreaks involved from 15 to 1,500 ill persons. Giardia lamblia was confirmed or suspected as the agent in nine outbreaks, rotavirus in one, and no agent could be identified in eight. Seventeen outbreaks occurred on surface-water systems; none of these had adequate chemical pretreatment and filtration. Investigation of water systems exhibiting positive coliform results during the first year detected no outbreaks. Activities important to effective surveillance included educational outreach programs to local health agencies, physicians and the public, and the designation of one individual to whom all water-related public complaints and health department inquiries were directed.

Septic cavernous sinus thrombosis.

Septic cavernous sinus thrombosis remains a potentially lethal disease, although advances in therapy have lowered the morbidity and mortality substantially. Prevention, early diagnosis, and aggressive treatment offer the best hope for recovery.

A community waterborne gastroenteritis outbreak: evidence for rotavirus as the agent.

A community waterborne nonbacterial gastroenteritis outbreak occurred in Eagle-Vail, Colorado in March 1981. Illness (defined as vomiting and/or diarrhea) was statistically associated with water consumption (chi 2 for linear trend = 7.07, p less than .005). Five of seven persons associated with the outbreak were infected with rotavirus as shown by virus detection or serological methods. Bacterial pathogens, Giardia lamblia, and Norwalk virus were excluded as responsible agents. Rotavirus should be looked for as a cause of waterborne outbreaks.