Organism that causes vision loss detected across NSW coast

A new study detected the microorganism Acanthamoeba at coastal sites, which can cause an extremely rare but potentially sight-threatening eye infection.

The condition, Acanthamoeba keratitis (AK), can lead to vision loss with around one quarter of infected patients ending up with less than 25 per cent of vision or becoming blind.

Swimmers should take off contact lenses before entering the water to avoid picking up the infection, according to the researchers.

This is because the organism can get trapped between the contact lens and the eye, leading to infection.

"Wearing contact lenses is the leading risk factor, particularly if people mix their contact lenses with contaminated water," lead author Binod Rayamajhee, who is completing a PhD focused on Acanthamoeba, said.

The condition is estimated to estimated to affect 10 to 40 Australians per year.

Previous studies suggested that nearly 20 per cent of patients acquired AK after swimming in seawater or fresh water with their contact lenses.

Researchers from the University of NSW previously found that around one third of the tap water in bathroom sinks in greater Sydney contains Acanthamoeba.

They found that washing contact lenses in tap water is a major risk factor for AK.

The coastal sites, which are used for swimming and kayaking, varied in prevalence of Acanthamoeba depending on their proximity to urban areas.

For the most highly urbanised site, more than 50 per cent of the samples tested positive. In contrast, for the least urbanised site, 32 per cent of the samples contained Acanthamoeba.

"The contaminated water allows the Acanthamoeba to flourish, as it feeds on the nutrients and a wide range of bacteria," Mr Rayamajhee said.

"When we look at global data, there are more AK cases during summer, when recreational activities are likely to be at their highest."

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With rising global temperatures and increased stormwater runoff, urbanised coastal waterways may become an ideal habitat for the microorganism, posing an increased public health risk.

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