The Centers for Disease Control (CDC) and Prevention has released a report that shows fewer Americans became sick from drinking tap water in 2001-2002 than in the previous two-year period.

Just published in the agency's Morbidity and Mortality Weekly Report, the study was conducted by Brian G. Blackburn, a CDC researcher, and other CDC and USEPA personnel who looked at 31 waterborne disease outbreaks (WBDOs) that were reported in 19 states during the study period.

According to the report, during 2001-2002, a total of 31 WBDOs associated with drinking water were reported by 19 states. These 31 outbreaks caused illness among an estimated 1,020 persons and were linked to seven deaths. The microbe or chemical that caused the outbreak was identified for 24 (77.4 percent) of the 31 outbreaks. Of the 24 identified outbreaks, 19 (79.2 percent) were associated with pathogens, and five (20.8 percent) were associated with acute chemical poisonings.

Five outbreaks were caused by norovirus, five by parasites and three by non-Legionella bacteria. All seven outbreaks involving acute gastrointestinal illness of unknown etiology were suspected of having an infectious cause. For the first time, the report included drinking water-associated outbreaks of Legionnaires disease, with six such outbreaks occurring during 2001-2002. Of the 25 non-Legionella associated outbreaks, 23 (92.0 percent) were reported in systems that used groundwater sources; nine (39.1 percent) of these 23 groundwater outbreaks were associated with private noncommunity wells that were not regulated by USEPA.

The total number of drinking-water associated outbreaks decreased from 1999-2000, a 20.5 percent decrease overall.