Undercooked Meat Linked to Risk of Vision Loss, Retinal Scarring: Study

While the parasite toxoplasma gondii is usually associated with handling cats and cat litter, new research finds the parasite, linked to vision loss, is more commonly contracted from undercooked meat.

The findings of a new study suggest that there may be a risk of vision loss from eating certain raw or undercooked meat, due to a parasite that can cause a form of retinal scarring.

The parasite toxoplasma gondii can cause severe retinal damage and even blindness, and researchers indicate that individuals may be exposed through undercooked meat or spending time around cats with the infection, according to a press release detailing new research from Flinders University in Australia.

Researchers analyzed retina photographs of over 5,000 people living in the Busselton area in Western Australia. They used scans originally collected to evaluate the prevalence of glaucoma and age-related macular degeneration for a long-term healthy aging study. The scans were assessed for toxoplasmic retinochoroiditis and positive cases were confirmed with antibody blood levels.

The data indicates one in 150 Australians were positive for the parasite, which is also linked to cats via toxoplasmosis. Most people are aware pregnant women can contract toxoplasmosis after handling the litter box of a cat, but the findings of this study highlight the other ways humans can be infected with the parasite.

Many animals around the world are infected by the toxoplasma gondii parasite and often contract the parasite in environments soiled by infected cats or by consuming other infected animals.

Humans can become infected after coming in contact with domestic cat feces, but the most common method of infection appears to be consuming raw or undercooked meat from infected livestock.

While Australia has a substantial population of feral cats know to be infected with the parasite, other sources also play a role in infection of the eye disease, including farming and a diet rich in meat. This is also the case for Americans.

There is no cure or vaccine, and symptoms vary, including retinal inflammation and scarring or ocular toxoplasmosis. However, most people are asymptomatic.

Other studies from around the world indicate 30% to 50% of the global population is infected with toxoplasma gondii. However, the findings of the new study highlight the pervasiveness of the parasite and the related eye disease.

Furthermore, infection can cause retinal scarring, which can lead to reduced vision in more than 50% of the eye. It can also result in the retina detaching and can even lead to blindness in some patients.