Saturday September 10, 2005 1:16 AM

AP Photo TXDZ108

By JIM VERTUNO

Associated Press Writer

HOUSTON (AP) - Doctors at the complex housing thousands of Hurricane Katrina evacuees said Friday they have contained a viral outbreak that caused diarrhea and vomiting among hundreds of people.

About 700 people have been treated, with 40 still in isolation to contain the virus, said Dr. Hermenia Palacio, director of Harris County Public Health and Emergency Services.

The evacuees were sick with norovirus, the same easily spread bug that's made many cruise ship passengers sick. While the norovirus was relatively mild, doctors took the precaution of isolating some people to keep it from running rampant.

An estimated 3,000 refugees are still in the Astrodome using public restrooms, and cots are lined up in close rows.

The sick were quarantined until they had no symptoms for 48 hours.

Tom Skinner, spokesman for the Centers for Disease Control in Atlanta, said there have been reports of similar outbreaks at shelters around the country but norovirus does not appear to be a widespread problem.

``We're getting reports of clusters of cases of diarrheal illness,'' Skinner said. ``In these shelters, it's important for the medical professionals to pay close attention to hygiene.''

Palacio said the norovirus outbreak at the Astrodome and Reliant Center in Houston peaked on Monday. ``We've been seeing fewer and fewer cases,'' since then, she said.

Such an viral outbreak poses the most serious threat to the oldest and youngest in the refugee population, Palacio said.

Many of the Astrodome's residents spent much of last week in New Orleans' rancid Superdome without working toilets and little clean water.

She said the refugees here have made at least 7,000 clinic visits and that doctors took some simple precautions to help prevent the spread of the virus.

``There's been more washing of hands than I've ever seen,'' she said.