Two people in Los Angeles have been infected with a raccoon-borne parasite that can burrow into the brain and cause blindness.
The individuals, who have not been identified, live in the South Bay region and have been diagnosed with Baylisascaris procyonis, or raccoon roundworm.
Raccoon roundworm is a common parasitic infection among raccoons, where a worm infects their intestines and its eggs are passed in their feces.
But infection is rare in humans and county officials say the risk to the public is currently “low.”
However, they are warning the public about the raccoon-borne parasite following a spike in rabid raccoons earlier this year and because the animals are increasingly being seen in neighborhoods where people are at higher risk of coming into contact with them.
Raccoons are increasingly appearing in neighborhoods, increasing the risk of people coming into contact with them and becoming infected (stock)
No further details about the patients, including their ages, genders and symptoms they had suffered, were disclosed.
However, symptoms of infection with the parasite include mild fever, fatigue or nausea, but can quickly progress to neurological symptoms.
In severe cases, organ damage can be so severe that patients die from the disease.
A county spokesperson said: ‘The confirmed cases of this rare infection are an important reminder for everyone in Los Angeles County to take precautions to prevent the spread of disease from animals to people.
‘While (raccoon roundworm) is rare in people… it is concerning because a large number of raccoons live near people and the infection rate in raccoons is likely high.’
To date, only 23 cases of raccoon roundworm in humans have been recorded in the medical literature, of which six patients (26 percent) died from the disease, but doctors say the number of cases is likely a vast undercount because the infection is often misdiagnosed.
Other patients have been left with lifelong disabilities, including blindness and brain damage.
Previous cases in the United States include that of a teenager from Brooklyn, New York, who was left blind in one eye in 2009, and that of a baby who suffered brain damage after contracting the disease.
In 2021, a one-year-old boy in Canada became infected after eating raccoon feces from a garden pot. He was quickly treated and suffered no long-term effects.
The graphic above, from the CDC, shows the life cycle of the raccoon roundworm.
It is estimated that between 40 and 60 percent of raccoons are infected with the raccoon roundworm parasite.
It does not cause symptoms in animals, but they can shed it in their feces (and humans then pick up the eggs if they come into contact with them).
In rare cases, dogs can serve as hosts for Baylisascaris procyonis.
After a person accidentally ingests the eggs, the parasites hatch in their intestines and migrate into the bloodstream.
From there, they travel to organs such as the liver, lungs, eyes and brain and tunnel into them, causing inflammation and damage to the surrounding area.
Symptoms may appear between one week and one month after infection.
Raccoon roundworm is diagnosed by testing to rule out other diseases. There is no specific test available for raccoon roundworm.
Treatment should be prompt and includes taking the antiparasitic drug Albendazole. If administered promptly, patients may not experience any side effects.