In an update on the rat lungworm cluster in Hawaii, an additional case was reported on Hawaii Island, bringing the cluster total to 15 this year, according to a HawaiiNewsNow report.

slugThis brings the tally in the state to nine Big Island residents, four in Maui residents and two visitors from San Francisco who stayed in the Hana area of Maui.

The most recent case has been hospitalized and released, according to health officials.

In 2016, there were 11 reported confirmed cases, all on Hawaii Island.

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.

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.