PORTLAND, Ore. (KOIN) — Vancouver Lake is closed to swimming and wading until further notice as health officials confirmed the presence of E. Coli first detected about one week ago.

A warning was issued to park-goers on June 2 when officials said routine testing showed “elevated” levels of E. Coli in the water, which can cause serious illness if swallowed.

On Friday, follow up tests confirmed the results with four of six samples showing high levels of the bacteria, Clark County Public Health said.

Health officials are also monitoring a “harmful” algae bloom at Vancouver Lake, but said toxin levels haven’t reached high enough to warrant an advisory. Regardless, changing weather and lake conditions can alter toxin levels during a bloom.

While those wishing to enter the water are prohibited, anglers are advised to avoid contact with the lake and “thoroughly clean all fish and equipment.” Pet owners are also being told to keep their furry friends away from the water.

More testing is scheduled for Monday, officials said, and the lake will stay closed to swimming until samples show E. Coli levels have returned below state and federal guidelines.

As long as the algae bloom persists, however, everyone using the lake should “avoid floating areas of scum when recreating in the water,” health officials said.

Vancouver Lake Regional Park is still open. Clark County Public Health said water in the park’s restrooms and shelters is not affected and is safe to drink.