Are you planning a summer holiday in Croatia? Warning for hotspot to visit after health chiefs spot a spike in travelers falling ill from a diarrhea-causing parasite lurking in swimming pools

Holidaymakers in Croatia have been hit by a wave of diarrhoea-causing parasitic infections.

Nearly twenty Germans who traveled to Croatia in 2023 were affected by cryptosporidium.

German health chiefs were shocked by the unusually high disease rates.

Typically, fewer than five infections can be traced back to the popular Balkan destination each year.

Officials investigating the surge of cases, located in Istria, a region on the Adriatic coast in northern Croatia, believe they all contracted the disease by swimming in contaminated pools.

Cryptosporidium, which can cause vomiting, stomach pain and fever, can survive in swimming pools for up to a week.

The chlorine-resistant parasite is spread through infected feces that end up in the mouth, for example while swimming.

Traces of dried feces can wash off an infected person’s anus.

According to the U.S. Centers for Disease Control and Prevention (CDC), infected people can shed up to 100 million cryptosporidium germs in one bowel movement. Swallowing just ten is enough to make you sick.

All 23 cases occurred between July 31 and October 1, according to an investigation by a team from the Heidelberg Institute of Global Health and the Robert Koch Institute.

They all had a ‘potential exposure’ in Croatia, but the exact cause cannot be proven.

But officials did not investigate whether the increase was due to more tourists from Germany visiting Croatia than in previous years.

Additionally, better testing in the wake of the pandemic may have detected more cases.

Yet increases in travelers becoming ill from cryptosporidium in other popular holiday destinations, such as France, Greece and Italy, have not been as sharp.

Writing in the diary Euro supervisionresearchers said: ‘The chance of exposure in Southern Europe — France, Greece, ItalyPortugal and Spain — were also increased, but to a much smaller magnitude, indicating an effect specific to exposure in Croatia rather than a general trend.”

Information about the locations of ‘potential exposure’ in the country was available in 21 cases.

Holidaymakers had stayed at 10 several camping resorts, nine of which were on the Istrian peninsula.

A survey distributed by health officials to help determine the cause of the outbreak – to which 15 of the 23 tourists responded – found that 14 of them had used swimming pools at their camping resorts.

Only two cases reported that they also swam in other pools or fresh water during their stay.

“The only case without pool exposure reported contact with a symptomatic individual within 14 days before illness onset,” health officials said.

While they acknowledged that heavy rain in early August could have caused water pollution, more than a quarter of cases had “already experienced symptoms” before the weather change, they added.

Biweekly analyzes and monitoring of seawater quality on Croatian beaches also reported ‘excellent water quality’ in Istria during the summer of 2023.

The number of cases of the diarrhea-causing parasite also rose “significantly” in Germany, researchers noted, from between 600 and 750 cases in 2018 and 2019 to 1,001 in 2023.

For most people, cryptosporidiosis – the technical name for the infection – is mild.

It usually goes away on its own, without any treatment, within a few days or weeks.

However, it can be more serious for vulnerable people, such as those with weakened immune systems and the elderly or patients undergoing cancer treatment.

Due to its highly contagious nature, people with symptoms such as diarrhea and vomiting are told not to stay at work or school until they have been free of these symptoms for at least 48 hours.

Last year one overview of worldwide parasite outbreaks found in water, swimming pools were found to be responsible for 92 percent of waterborne cryptosporidiosis outbreaks studied.

In October, officials from Britain’s Health Security Agency also said Britain was hit by an “unprecedented” outbreak of the diarrhea-causing parasite.

Officials investigating the unusual cluster of cryptosporidium cases believed it could be linked to holidays abroad as dozens of affected Britons had traveled to Spain and other Mediterranean countries.

Between August 14 and October 1, 2,411 cases were recorded in the UK.

The number of weekly reports peaked at 450 at the end of September – three times as many as normally expected.