The number of confirmed cases of E. coli in western Wyoming along the Idaho border reached nine on Monday, while another 32 people showed symptoms of infection, state health officials said.

"We have no indication that this is spreading across Wyoming," state epidemiologist Gayle Miller said. "We don't have other cases at this point in time that appear to be linked to that outbreak."Two people remained hospitalized, including a 2-year-old girl from Alpine listed in serious condition at a Jackson hospital. Miller said she was being watched closely for signs of kidney damage.

The other, an Alpine resident about 65 years old, was listed in good condition at an Afton hospital, she said.

The majority of infected people live in Alpine, and most became ill June 28 or 29, Miller said. At the height of the outbreak, which started last Monday, six people were hospitalized.

"Because of the very limited nature of this illness, . . . that definitely points to a single source as the item of contamination," she said.

That source, however, may never be identified, she said.

Alpine's water supply comes from two wells and a spring. It is being repeatedly tested, but none of the tests have indicated the presence of the bacteria.

"It's possible that a rain event or something like that could wash organisms through the system. It could be a very short-lived event," said Chuck Higgins, consumer health services manager for the state Agriculture Department.

Area lakes are also being tested.

Other possible sources being investigated include major social events, grocery stores and restaurants.

Alpine residents have been asked to boil drinking water until the source can be pinpointed or the water is deemed safe.