A popular children's play area at Hamilton's Parana Park has been linked to 11 cases of gastrointestinal disease in the last three weeks.
Hamilton City Council and the Waikato District Health Board's public health unit have been monitoring cases of cryptosporidiosis associated with the park's water feature since February 5, when a member of the public alerted the council to the issue.
Cryptosporidiosis, a parasite found in the guts of birds, animals and humans, can be linked to recreational water use, and in particular, faecal contamination of swimming pools.
Common symptoms include diarrhoea, stomach cramps and abdominal pain.
Dr Anita Bell, medical officer of health at the Waikato DHB, said measures to deal with the public health threat, including emptying and cleaning of the water feature twice, were put in place immediately after they were made aware of the problem.
"At the moment I think we've done what we need to do to minimise the risk. It looks like it is enough, but we probably won't see that for another week or so."
Dr Bell confirmed shutting down the feature, which was part of a $435,000 upgrade to the park last year, had been discussed by the council and DHB.
Sally Sheedy, manager for parks and open spaces at the Hamilton City Council, said the council was taking all the right steps to address the issue.
"We have taken the concerns raised extremely seriously, as the health of the public using the park is very important to us."
Along with emptying and cleaning of the feature, new signage reminding parents that the water feature was in a natural environment went up yesterday, Dr Bell said.
Ms Sheedy admitted that before the incident there had not been appropriate warnings about the possible health risks associated with the feature.
"We have responded quickly with the installation of signage and some clear messaging to parents whose children are using the water feature," she said.
The council was relying on parents to contact them if their children "toilet" in the water feature, so the council could close it and treat the water.
"Our message to parents with young children is to ensure their children do not put their heads under the water."
Although the exact cause of the contamination is uncertain, Dr Bell said there were two likely scenarios: the natural environment of the park, and faecal accidents in the pond. However, she said anecdotal evidence suggested a number of faecal accidents had occurred.
"You have to say, it has been in use for quite a long time, and this is the first time we have seen anything like this."
Although cryptosporidiosis is present year round, Dr Bell said there were
typically large increases in spring, because of farming, and summer, as a result of higher public pool use. Ms Sheedy said the particularly hot summer had seen high usage.
The children's play area on Memorial Drive in Hamilton East was reopened in April last year after a $435,000 upgrade, paid for by the council and several sponsors. Along with new paths, sculptures and viewing platform looking over the Waikato River, the existing water feature was extended and the water pump and filtration system replaced.
Monitoring of the water feature by the DHB is ongoing.
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