Better intervention strategies are needed to reduce the risk of waterborne outbreaks.

Field investigation of 27 medium to small water systems in Ontario Province has revealed a pattern of deviations in operations that is similar to those reported in the United States over the past 25 years. In this recent Ontario survey of water utilities, the key findings were: (1) a need for full cost pricing of public water supply to consumers; (2) better understanding of water treatment train performance; and (3) a need for management driven accountability to search beyond regulatory minimum requirements for safe water quality. Much of the deteriorating state of operations was a reflection of limited financial base to support an effective management programme.

A community waterborne outbreak of salmonellosis and the effectiveness of a boil water order.

Objectives: A 1993 large water-borne outbreak of Salmonella typhimurium infections in Gideon, Mo, a city of 1100 with an unchlorinated community water supply, was investigated to determine the source of contamination and the effectiveness of an order to boil water.

Methods: A survey of household members in Gideon and the surrounding township produced information on diarrheal illness, water consumption, and compliance with the boil water order.

Results: More than 650 persons were ill; 15 were hospitalized, and 7 died.

A waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody diarrhea and death.

Objective: To describe and determine the source of a large outbreak of Escherichia coli O157:H7 (ECO157) infections in Missouri.

Design: A case-control study and a household survey.

Setting: A small city in a rural Missouri township that had an unchlorinated water supply.

Drinking water microbiology--new directions toward water quality enhancement.

Drinking water microbiology has emerged from decades of relative complacency to recognize there can be major concerns with potable water quality. Many of these issues are a result of an explosion of information on new waterborne agents, treatment problems with raw-source water qualities, biofilm development in some distribution systems and specialized requirements in water quality unique to hospitals and industries. Protozoan cyst survival after some disinfection practices involving surface water impoundments and virus occurrence in poorly protected groundwaters have provided reasons for expanding minimum treatment of surface waters and for requiring disinfection of all groundwaters unless there is a demonstrative data base to support exceptions in treatment requirements.

Nonphotosynthetic pigmented bacteria in a potable water treatment and distribution system.

The occurrence of pigmented bacteria in potable water, from raw source water through treatment to distribution water, including dead-end locations, was compared at sample sites in a large municipal water system. Media used to enumerate heterotrophic bacteria and differentiate pigmented colonies were standard method plate count (SPC), m-SPC, and R2A agars, incubated up to 7 days at 35 degrees C. The predominant pigmented bacteria at most sample locations were yellow and orange, with a small incidence of pink organisms at the flowing distribution site.