Parasitic brain worm found in rats at Zoo Atlanta, CDC study says

ATLANTA, Ga. (Atlanta News First) - A parasite that often invades the brain in humans was located in wild brown rats found dead at Zoo Atlanta, according to a study from the Centers for Disease Control and Prevention (CDC).

The researchers found Angiostrongylus cantonensis, or “rat lungworm,” in several rats from 2019 to 2022, the study said. The find may “pose a possible threat to the health of humans and domestic, free-ranging, and captive animals,” according to the study.

The parasite can cause eosinophilic meningitis in humans, with symptoms of a stiff neck, tingling in the skin, nausea and vomiting. But the parasites can’t live long in humans and are rarely dangerous, the CDC said. Most people recover without treatment.

The adult form of the parasite is only found in rodents, according to the CDC — but the larvae live in snails and slugs, which humans can eat and get sick. Some raw produce like lettuce may also contain small snails that carry the parasite.

The parasite is often found in parts of Asia and the Pacific Islands, but cases have been identified in the United States as well. The study says the parasite was likely in Georgia before 2019, as it was found earlier in nearby Florida and Alabama. From 2011 to 2016, six suspected human cases were identified in Texas, Tennessee and Alabama, the study said.

In a statement, Vice President of Animal Health at Zoo Atlanta Sam Rivera said:

“This parasite is in Georgia, not limited to Atlanta. Zoo Atlanta is unique in the sense that our Veterinary Team regularly screens rats for infectious diseases, which is why data from the Zoo was able to be used to contribute to the University of Georgia’s study, which refers to the whole state. Zoo Atlanta has an extensive rodent control program in an attempt to eliminate contact between Zoo animals and rodents such as rats.
Additionally, like domestic animals, many animals here at the Zoo receive monthly anti-parasitic medication to help prevent infection by intestinal parasites and heartworms. This medication is also effective against the larvae of the rat lungworm.
The likelihood of humans contracting this parasite at the Zoo is almost zero. Humans cannot get this parasite directly from rats. Humans are infected by consuming undercooked meat from the parasite’s larvae hosts, which can include frogs, fish, crustaceans, snails, and slugs.”
Sam Rivera, DVM Animal Health at Zoo Atlanta

The parasite’s spread to the south is likely due to human disturbance and food web changes caused by climate shifts, according to the study.

The CDC says to contact your health provider if you suspect you may have ingested the parasite. Click here to learn more about Angiostrongylus cantonensis.