Rat Lungworm Disease

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Rat lungworm, also known as Angiostrongylus Infection, is a disease caused by the ingestion of a parasite, often passed on from snails or slugs. The disease can affect the brain and spinal cord, and lead to severe headaches, neck stiffness, temporary paralysis and sometimes even death. Hawaii has seen cases of rat lungworm going back decades, but it received widespread attention in April 2017 with reports that a couple of California newlyweds who spent their honeymoon on Maui had returned home with the disease.


Number Of Cases

The Hawaii Department of Health said 76 cases of rat lungworm were reported in the state from 2007 to mid-April 2017. The department was able to confirm about half of those. The rest were considered probable cases of the disease. Despite a spike of reported cases in early 2017, state epidemiologist Dr. Sarah Park said the outbreak didn’t constitute an “epidemic.”

More than 2,800 cases of the disease were reported in about 30 countries as of 2015, according to the U.S. Centers for Disease Control and Prevention. Most of the cases were in Southeast Asia and the Pacific. In 2010, the CDC said “very few” cases of rat lungworm had appeared in the continental United States, but it noted one unusual case in Louisiana:

In 1993, a boy in New Orleans got infected by swallowing a raw snail “on a dare. ” The type of snail he swallowed isn’t known. He became ill a few weeks later, with muscle aches, headache, stiff neck, a slight fever, and vomiting. His symptoms went away in about 2 weeks, without treatment of the infection.


Some people infected by rat lungworm never show symptoms, according to the state health department. Others may experience a rare type of meningitis If symptoms appear, they can include:

  • Severe headaches
  • Neck stiffness
  • Tingling or pain in the skin and extremities
  • Fever
  • Nausea
  • Vomiting
  • Temporary paralysis in the face
  • Sensitivity to light

The symptoms normally last two to eight weeks and go away on their own, according to the Centers for Disease Control and Prevention. However, the CDC noted, severe cases “can rarely occur, leading to neurologic dysfunction or death.”

The CDC said you should speak to your health care provider if you think you may have been infected.

How People Catch It

Despite its name, rat lungworm is generally passed to people through snails or slugs. It can also be carried by other animals, including freshwater shrimp, land crabs and frogs, according to the state health department. These animals ingest the larvae of the parasitic worm, and it matures in their bodies. If a person eats one of the infected animals, either raw or undercooked, the worm can infect the person. It’s also possible to become infected by eating raw produce that contains a snail or slug. The parasite, however, can’t be transferred from person to person, according to the health department.

The name comes from the main carrier of the disease: rats, which, if infected, will drop the larvae in their feces. That larvae then is eventually ingested by the other animals.

In some of Hawaii’s 2017 cases, state health director Dr. Virginia Pressler said, people were infected by drinking a homemade kava brew, which was prepared in uncovered buckets. The people later found slugs at the bottom of the serving bowl, she said.

How To Avoid It

The state health department has some advice on how to avoid rat lungworm disease:

  • Avoid eating raw or undercooked snails and slugs
  • Wear gloves and wash your hands if you handle snails or slugs
  • Inspect and rinse produce, particularly leafy greens, before eating
  • Boil snails, slugs, freshwater prawns, crabs and frogs for at least three to five minutes
  • Get rid of snails, slugs and rats near your home or garden


Rat Lungworm Disease
Rat Lungworm Disease
Tad Bartimus: What You Need To Know About Rat Lungworm Disease Courtesy of Maui Invasive Species Committee via Dr. Robert Cowie

Tad Bartimus: What You Need To Know About Rat Lungworm Disease

With cases now confirmed on three islands, Hawaii residents should be taking precautions, especially against the “semi-slug.”

Tad Bartimus: Living With The Horrors Of Rat Lungworm Disease Courtesy of Tricia Mynar

Tad Bartimus: Living With The Horrors Of Rat Lungworm Disease

A Maui woman talks about her ordeal, which began with flu-like symptoms and morphed into a smorgasbord of pain.