Ocular toxoplasmosis found to be common among Australians

Ocular toxoplasmosis has been found to be common in Australians

One in 150 Australians has retinal scars caused by the Toxoplasma parasite, according to a new Flinders University analysis.

An eye scan showing ocular toxoplasmosis. Photo: João M. Furtado

With a condition that puts people at risk of more attacks of toxoplasmosis that can progressively damage the retina and lead to vision loss, experts are calling for greater awareness of the dangers of eating raw and undercooked meat.

Closely related to cats, tOxoplasma It is a parasite that causes the infectious disease known as toxoplasmosis. Many animals around the world become infected, and they usually become ill in environments contaminated with infected cats or by consuming other infected animals.

For humans, while domestic cat feces can be carriers, the most common method of infection is by eating undercooked or raw meat obtained from infected livestock.

Given the large number of wild cats in Australia known to be infected, along with high levels of farming and meat-rich diets, it is essential that we understand the disease’s spread across the country,”

Professor Justin Smith, first author of the study, strategic professor of eye health and vision, Flinders University.

“While there is no cure or vaccine, the symptoms of toxoplasmosis vary depending on the age, health, and genetics of the affected individual. Many people do not have symptoms, but the most common disease we see in the clinic is retinitis and scarring known as ocular toxoplasmosis.”

“Studies around the world show that 30% to 50% of the world’s population is infected with toxoplasmosis, but despite knowing this, what we didn’t know was how common the associated eye disease is.”

In the study published in the journal, Ophthalmology RetinaProfessor Smith and her team analyzed retinal images of more than 5,000 people living in the Busselton region of Western Australia, which were previously collected to assess the prevalence of glaucoma and age-related macular degeneration for the long-term study of healthy aging.

Three specialist ophthalmologists, including Professor Smith, evaluated screening tests for toxoplasmic choroidal retinitis, with positive cases confirmed by antibody blood tests.

“Out of 5,000 subjects, we found 8 participants with blood-test-confirmed toxoplasmic retinal scars. Add to this that about three-quarters of retinal lesions would be invisible on these particular images, we were able to estimate the prevalence of ocular toxoplasmosis to be 1 in 149 people. , “ Professor Smith says.

The work represents the first effort to determine the rate of ocular toxoplasmosis in Australia, with findings indicating that the condition can be considered common.

With previous research showing that infection can lead to double vision in more than 50% of eyes and even blindness, the authors say it’s important for people to understand toxoplasmosis risk factors and ways to avoid them.

“While people are often aware of pregnant women who need to avoid cat litter trays, we also need everyone to know that meat preparation is an important risk factor,” Professor Smith says.

Research conducted by Professor Smith in 2019 highlighted the high prevalence of Toxoplasma in Australian lamb sold in supermarkets.

Add to this that it is now common to prepare meat in and out of restaurants to be thoroughly cooked or raw, and people are more likely to contract toxoplasmosis.

“We need people to realize that this disease exists, so they can make informed decisions about how to prepare and eat their encounters. The parasite can be easily killed by cooking meat to an internal temperature of 66°C (or medium) or by freezing it before cooking”.

The research follows a series of papers recently published by Professor Smith and his team on the condition, including one that uses a new retinal imaging technology to show changes that occur in ocular toxoplasmosis at the tissue level, and one that highlights better clinical outcomes. Exercise for disease management.

“Prevalence of toxoplasmic retinitis in the Australian adult population: a community study” by Lecia P Ferreira, Joao M. Furtado, Jason Charing, Maria Franchina, Janet M. Matthews, Aus Al Mullan, Michael Hunter, David A. McKee and Justin R. Smith in the magazine Ophthalmology Retina. DOI is coming.

The paper’s co-authors are from the University of São Paulo Brazil, the University of Western Australia, Edith Cowan University, PathWest Laboratory Medicine WA and the Queensland Eye Institute.


Journal reference:

Ferreira, L.B., et al. (2022) Prevalence of toxoplasmic retinitis in the Australian adult population: a community study. Ophthalmology Retina. doi.org/10.1016/j.oret.2022.04.022.

2022-05-16 04:56:00

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