Monday, April 6, 1998 | 10:20 a.m.
The Metropolitan Water District of Southern California has given Southern Nevada water officials an extra $80,000 to study cryptosporidium, a one-celled organism that killed 43 people in Las Vegas during 1994.
The Southern Nevada Water Authority is participating in an international study to find the best ways to kill the cells that cause watery diarrhea. In people with weakened immune systems, the organism can cause death.
The Las Vegas Valley outbreak affected 132 people who suffered for up to three weeks from watery diarrhea, fever and severe abdominal cramps. Another 43 died, according to the Centers for Disease Control and Prevention in Atlanta, which investigated the local outbreak following one in Milwaukee during 1993.
Although no cells were ever found in Southern Nevada's treated water, the CDC suspected tap water from the Colorado River spread the cryptosporidiosis throughout the Las Vegas Valley.
Southern California and Southern Nevada water officials plan to install ozone treatment plants that the Southern Nevada Water Authority estimates will cost up to $17 million to build by 2000, SNWA spokeswoman Stephanie Stallworth said.
The Metropolitan Water District, which serves Colorado River water to thirsty Southern Californians, is interested in how well ozone kills the organism, said Mark Beuhler, MWD's director of water quality.
Chlorine doesn't stop crypto, Beuhler said. Only microscopic filters can keep it out of the water or there is ozone.
But if too little ozone is used or there is too much crypto in the water, some can get into the drinking supply.
More than 300 cases of cryptosporidiosis were confirmed in Great Britain during 1997 in a drinking supply system using groundwater treated with ozone and granulated active carbon filters.
Such outbreaks prompted Metropolitan to ask for more time and more testing, Beuhler said.
Montgomery Watson of Pasadena, Calif., will conduct the testing.
Results are expected in time for the international report prepared with the help of the American Water Works Association Research Foundation by Jan. 1.
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