In a follow-up on the Angiostrongyliasis, or rat lungworm situation in Hawaii, state health officials say for the past three months they have been investigating a cluster on the island of Maui.

rat lungworm
Angiostrongylus cantonensis life cycle/CDC

According to Janice Okubo, Communications Director for the Hawaii State Department of Health (DOH) in an email to Outbreak News Today, in 2017 the Department has confirmed four (4) Maui resident cases of rat lungworm infection and two (2) non-resident cases (out-of-state visitors who travelled to Maui).

In addition this year, there have also been three (3) confirmed Hawaii Island resident cases.

DOH is currently investigating three (3) reported cases of possible rat lungworm infection on Maui and at least one (1) possible case on Hawaii Island.  These cases are under investigation and have not been laboratory confirmed.

Okubo says the investigation is fluid and the cluster of cases, though not all confirmed, are very concerning.

Last year in 2016, there were 11 reported confirmed cases, all on Hawaii Island.  The recent cluster of cases this year on Maui suggests that something may have changed on Maui to increase the risk there similar to the Big Island.

Hawaii typically sees reports of 1-9 cases of rat lungworm each year. Since 2007, there have been two (2) related deaths.  It is not always clear how each case became infected. Testing for the disease is challenging and requires spinal fluid from the sick person.

Angiostrongyliasis, also known as rat lungworm, is a disease that affects the brain and spinal cord. It is caused by a parasitic nematode (roundworm parasite) called Angiostrongylus cantonensis.

The adult form of A. cantonensis is only found in rodents. However, infected rodents can pass larvae of the worm in their feces. Snails, slugs, and certain other animals (including freshwater shrimp, land crabs, and frogs) can become infected by ingesting this larvae; these are considered intermediate hosts. Humans can become infected with A. cantonensis if they eat (intentionally or otherwise) a raw or undercooked infected intermediate host, thereby ingesting the parasite.

Sometimes people can become infected by eating raw produce that contains a small infected snail or slug, or part of one. It is not known for certain whether the slime left by infected snails and slugs are able to cause infection. Angiostrongyliasis is not spread person-to-person.

Slug/Hawaii DOH
Slug/Hawaii DOH

Symptoms of angiostrongyliasis may include severe headache, stiffness of the neck and back, skin tingling, pain and sensitivity, sensitivity to light, hallucinations, nausea, vomiting and sometimes coma and death.

There is no medication or specific treatment for the infection.

The DOH is focusing on educating the community to prevent the spread of this serious and rare illness.  A community meeting was held last week on Maui and the department is working with the Maui Invasive Species Committee and the County of Maui on sharing information with the community.  Wider statewide public education efforts are also being planned since cases have been confirmed over the past several years throughout the state.

Health officials stress prevention methods to avoid contracting this serious parasitic infection. It’s important to appropriately store, inspect, and wash produce, especially leafy greens.  Be sure young children are watched while playing outdoors to prevent them from accidentally putting a snail/slug in their mouth, and take precautions to try to control slug/snails as well as rats around properties, especially if one maintains a home garden.


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