The disease remains rare; however, what concerns health policy makers is that the number of cases of rat lungworm disease have tripled over the course of the past decade (a seventh case involving a Maui woman who believes she contracted the parasite on the Big Island is under review). The disease is caused by Angiostrongylus cantonensis, a parasitic nematode (or roundworm). The roundworm causes the disease angiostrongyliasis. This is a cause meningitis and untreated the disease can cause permanent damage to the central nervous system or death, according to the U.S. Centers for Disease Control and Prevention.
The common name for the disease (“rat lungworm disease”) is because the nematode commonly resides in the pulmonary arteries of rats. Aside from rats, snails are the a common intermediate host; in snails, larvae develop until they become infective. People primarily become infected through the ingestion of larvae in raw or undercooked snails or other vectors, or from contaminated water and vegetables. The transmission in Hawaii appears to be (according to The Atlantic):
Rats host the worm and pass larvae through their feces, which are eaten by slugs. Humans are then infected after eating raw fruits and vegetables contaminated by the slug.
According to Hawaii’s state official epidemiologist Dr. Sarah Park the disease is nasty. She told Stat News: “If you could imagine, it’s like having a slow-moving bullet go through your brain and there’s no rhyme or reason why it’s going to hang out in this part of the brain or that part of the brain.”
The island of Maui is the second-largest of the Hawaiian Islands at 727.2 square miles and is the 17th-largest island in the U.S. The island is popular with tourists and Maui is a leading whale-watching center in the Hawaiian Islands due to Humpback whales wintering in the sheltered.
Combating the disease is likely to prove difficult due to the multiple vectors, remoteness of the island and dense undergrowth. However, good practices should safeguard people according to sanitation official Peter Oshiro, who told Hawaii News Now: “All our rules we have in place now, if followed, are more than adequate, and we’re very confident that it can prevent the occurrence of any more rat lungworm diseases from any of our regulated establishments.”