Out of the pool! Parasites linked to illness outbreaks

Some icky news just in time for pool season: Reports of diarrhea outbreaks linked to cryptosporidiosis parasites in pools and water parks increased at least twofold in two years, federal health officials reported Thursday.

The parasite, called crypto for short and spread through human feces, caused at least 32 outbreaks in 24 states in 2016, compared with 16 nationwide in 2014, according to the federal Centers for Disease Control and Prevention. Final numbers for 2016, along with 2015 numbers, will come in a later report, but “we expect them to go up,” said Michele Hlavsa, head of CDC’s healthy swimming program.

It is possible the increase is linked to better reporting, but it also is possible the problem is becoming more common, Hlavsa said.

Total cases reported to CDC have in- creased from about 1 in 100,000 in the early 1990s to about four in 100,000 in recent years, she said. That means an average of 8,000 people a year suffer through as many as three weeks of watery diarrhea, stomach cramps, nausea and sometimes vomiting — most often because they swallowed contaminated pool water.

Big outbreaks in 2016 included one in Arizona that sickened a Little League team and a cluster of outbreaks in Ohio that started in a water park and spread to nearby pools, contributing to nearly 2,000 cases statewide, adding to details published in CDC’s Morbidity and Mortality Weekly Report.

But do not be too quick to blame pool operators, Hlavsa said. Unlike other bugs that sometimes spread in pools, crypto can survive for up to 10 days, even in well- treated pools.

“This is a really tough bug to kill once it gets in the water,” Hlavsa said. When an outbreak is detected, operators have to close their pools and treat them with levels of chlorine that would not be safe for swimmers.