Every day, people from around the world visit Vancouver, and many spend time enjoying the city's beautiful beaches.

But cooling off in the waves this week could get them sick thanks to high levels of E. coli, a bacteria associated with human and animal feces.

Locals told CTV News they feel bad for visitors who arrive in the city only to learn some of its most popular swimming spots are off-limits, and for disgusting reasons.

"It's kind of embarrassing that we're not taking care of the water better," one jogger said. "When you come to a major city like this, you want to go into the water."

One group of tourists who travelled all the way from Spain told CTV News they hoped to feel the Pacific Ocean. Unfortunately, they were at Sunset Beach, one of four areas in the city currently marked by E. coli warning signs.

Health officials issued new swimming advisories at Sunset, English Bay and Jericho Beach over the weekend due to concerns about gastrointestinal illness. Trout Lake has been closed for weeks for the same reason.

And it's not just swimmers who need to watch out – any activity that can result in water splashing into your mouth is ill-advised when bacteria levels are high.

Dr. James Lu from Vancouver Coastal Health said the water can even pose a potential risk to people's pets.

"If a dog drinks the water and if the water is contaminated, it's not very good for the dog," he told reporters Monday.

Symptoms of E. coli infection include nausea, vomiting, diarrhea, headaches, mild fevers and stomach cramps. The symptoms appear within one and 10 days of exposure, and usually end within another 10 days.

Officials still don't know for sure what caused the E. coli levels to spike, but Dr. Lu said he suspects there are a range of factors, including an increase in boating activity and more people bringing their dogs to the beach.

Hotter weather brought on by climate change also likely plays a role, according to Lu.

"With hot weather bacteria does grow, and it could be as simple as that," he said.

It's unclear how long it could take for the bacteria levels to subside. Another round of E. coli test results are expected to be released on Tuesday.

With files from CTV Vancouver's Shannon Paterson