Worm that jumps from rats to human brains invades southeastern US

A worm parasite that is typically found in rats and slugs, but can jump to mammals, has become more widespread across the southeastern region of the US, a new study by the Centers for Disease Control and Prevention claims.

Scientists from various veterinary schools across the US studied 33 wild rats at a zoo in Atlanta between 2019 and 2022.

A. cantonensis, otherwise known as rat lungworm, was found often in their samples, with seven of the rats having lungworm infection.

The study said they are concerned about a “possible threat to the health of humans,” as well as domestic, free-ranging and captive animals, as they all can become accidental hosts to this parasite.

The worms live within the arteries around a rat’s lung, with larvae eventually bursting out of the lungs and going into their digestive system and out through their faeces.

Snails and slugs are likely to pick up the larvae through the softness of their bodies or by consuming the rat faeces.

Those gastropods could then be consumed by humans, either on purpose or by accidentally eating food or water that has been contaminated with slime.

Rat lungworm cannot be transmitted human-to-human.

When the parasite finds itself in a human, it could just cause some symptoms, such as nausea, vomiting, neck stiffness and headaches.

However, in rare cases, it can lead to nerve damage, paralysis, coma or death in rare cases, according to the CDC.

In humans, the parasite heads straight for the spinal cord and brain rather than the lungs.

According to the study, it is believed the worm can’t complete its life cycle in humans and will just lie in the brain before immune responses kill it off.

The illness is thought to last around two weeks to two months, but can be longer and also has similar symptoms to bacterial meningitis.

The parasite was initially reported in Hawaii, then later in Texas, Louisiana, Alabama, and Florida, likely due to infected rats and gastropods travelling on trading transport, such as on merchant ships, the study says.

The parasite is believed to have originated from parts of Asia, where most human cases developed thus far.

There is no specific treatment yet for the disease, however, Hawaiian officials, said that steroids and anti-parasitic drugs can help the inflammation that is caused by the dead worms in the body.

As of September 2023, there have only been 5 cases since 2022 in Hawaii. In the southeastern US, only a few sporadic cases have been recorded.