A microorganism that can cause a potentially blinding eye infection has been detected at four popular swimming spots in NSW.
Australian and Scottish researchers made the discovery during a world first study to find if the microorganism was present in Australian seawater.
It was found in seawater at all four coastal lagoons on the NSW central coast – Wamberal, Terrigal, Avoca and Cockrone – tested between July 2019 and August 2020.
The microorganism called Acanthamoeba can cause an extremely rare but potentially sight-threatening eye infection that attacks the clear outer layer at the front of the eye, called the cornea.
It feeds on bacteria and corneal cells leading to inflammation and potentially serious damage of the cornea.
More than a quarter of patients have lost more than 75 per cent of vision or at worst become blind.
There are currently no drugs that can kill the Acanthamoeba infection.
Swimmers are being warned the leading risk factor of contracting the infection is wearing contact lenses into the water.
“Wearing contact lenses is the leading risk factor, particularly if people mix their contact lenses with contaminated water,” UNSW PhD candidate Binod Rayamajhee and co-author of the research said.
Swimmers have being urged to take off contact lenses before entering the water to avoid picking up an infection.
While the infection is considered to be very rare with less than 40 Australians impacted every year, the risk appears to be higher for people swimming in sea or freshwater.
“There have been two previous studies, one in Sydney and another in Melbourne, suggesting that nearly 20 per cent of patients acquired AK after swimming in seawater or freshwater with their contact lenses,” Mr Rayamajhee said.
The Risk to contact wearers is also not confined to swimming spots, with previous research indicating the infection causing microorganism has been found in tap water across Sydney.
About one third of the tap water in bathroom sinks across Greater Sydney is estimated to contain Acanthamoeba, UNSW research from 2019 suggests.
Contact wearers are advised to avoid washing the lenses in tap water, showering with them in and always dry hands before touching the lenses.
Avoiding the infection
- Contact lens wearers should not panic or avoid swimming altogether, but they should be careful.
- They should monitor for early symptoms such as eye pain and redness, blurred vision, light sensitivity and excessive tearing.
The research found that urban coastal sites are an ideal environment for Acanthamoeba to flourish due to presence of human created contaminants like sewage.
They also found it was more prevalent in the water during the summer months, when recreational activities are likely to be at their highest.
The new research is a collaboration between UNSW Sydney, University of Technology Sydney (UTS) and the University of the West of Scotland.