Parasite causing vision loss found in Aussie supermarket meat

Millions of Australians are infected with a potentially-blinding parasite, but researchers say many are unaware the most common cause of infection is from what's served up on your dinner plate.

While transmission of the toxoplasma parasite is often associated with cats and their faeces, its most common route into humans is from the consumption of meat.

"Grazing livestock can catch the parasite from poop from cats and in rural Australia many of those are feral cats," Professor Justine Smith from Flinders University's College of Medicine and Public Health told Yahoo News Australia.

That means the meat you buy from the supermarket, whether it be red or white, is at risk of carrying the parasite.

Prof Smith, whose research focuses on the effects of viruses and parasites on the eye, released new research on Thursday that indicates roughly one in 150 people have suffered from scarring to their eyes as a result of the eye disease ocular toxoplasmosis.

An eye scan showing ocular toxoplasmosis. Source: Supplied
An eye scan showing ocular toxoplasmosis. Source: Supplied

The research was the first time the rate of ocular toxoplasmosis has been quantified in Australia, with researchers unaware of just how common it is.

Such scarring on the retina can lead to a loss in vision for those affected, and in extreme cases, blindness. Prof Smith says it's a misconception young, health adults are immune to such damage.

She said over half of the people who had come to the eye clinic with the eye disease had suffered a loss of vision below the legal driving level.

How to prevent toxoplasma infection

Prof Smith says there is a major lack of awareness of preventative measures, the main being cooking meat sufficiently enough to kill the parasite.

"On cooking TV shows they often promote hardly cooking your red meat... and even things like chicken sashimi are starting to become popular," she told Yahoo.

"Years ago people used to cook their meat quite well because they knew there were a number of diseases in meat and as times evolved and we have less and less concerns about infections, this point has been lost."

Rare steak, which could be increasing our risk of ocular toxoplasma.
Rare steak is popular among Australians – but could it be increasing our risk of ocular toxoplasma? Source: Getty, file.

Prof Smith says your meat doesn't have to be "like leather" and simply needs to be to cooked an internal temperature of 66C to "what is effectively medium". Freezing meat before eating it can also kill the parasite.

Prof Smith said she would support a push to have advisories about cooking meat placed on meat packaging.

She said education about toxoplasma in schools would also be beneficial to raising awareness.

At least 30 per cent of the Australian population is believed to be infected by toxoplasma, however a study in Western Australia found the community that was studied had an infection rate as high as 66 per cent.

Prof Smith noted while organic meats are hailed as a healthier and more sustainable alternative, they may be more prone to toxoplasma due to the livestock often being allowed to roam freely.

Lamb is understood to be the most common carrier of toxoplasma, but it is found in all meats, including kangaroo.

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