Swimmers in the Capital Region can breathe a little easier after an alarming study was released last week.

The Centres for Disease Control warned of a parasite that can survive in chlorinated water and cause cryptosporidiosis, a watery diarrhea that can last up to three weeks.

Young children and seniors or those with weak immune systems can get very sick from the disease.

But there's good news for anyone who frequents pools in Greater Victoria as most pools here don't rely on just chlorine to clean.

Commonwealth Pool in Saanich and Oak Bay and Esquimalt rec centres treat their water with ultraviolet radiation, which is effective in killing cryptosporidiosis.

Crystal Pool in Victoria in an exception as it relies primarily on chlorination. City officials say the pool does have filters that capture crypto spores.

Health officials advise anyone to avoid swimming in public pools if they or their kids or sick and say there are ways to avoid getting sick at recreation centres.

"That's why we've got the showers at the pools. Definitely recommend people shower before they go in the swimming pool, and then after, and also make sure you're washing your hands before you eat anything," said Island Health Medical Officer Dee Hoyano.

Infections from the parasite have gone up by about 13 per cent every year, and in Canada there have been 13,451 cases reported between 2000 and 2016.

In 2017 there were 88 cases of crypto reported in B.C. and eight on Vancouver Island.

With a report from CTV Vancouver Island's Brad MacLeod.