9 Cases of Rat Lungworm Disease Confirmed in Hawaii

CNN/Stylemagazine.com Newswire | 4/11/2017, 8:53 a.m.
The Hawaii State Department of Health has confirmed six cases of rat lungworm disease on the island of Maui and ...

By Susan Scutti

CNN

(CNN) -- The Hawaii State Department of Health has confirmed six cases of rat lungworm disease on the island of Maui and three cases on the Big Island over the past three months, an official said Monday. No deaths have been reported.

Rat lungworm disease, a parasite officially known as Angiostrongylus cantonensis, affects the brain and the spinal cord, according to the Centers for Disease Control and Prevention.

Three possible cases on Maui are also under investigation along with one suspected case on Hawaii, said Janice Okubo, a spokeswoman for the Department of Health. The confirmed cases on Maui involve four residents and two visitors, and the confirmed cases on Hawaii involve residents only.

Typically, the state gets reports of one to nine cases of rat lungworm each year, with two related deaths since 2007, Okubo said.

"The investigation is fluid and the cluster of cases, though not all confirmed, are very concerning," Okubo wrote in an email.

The state cannot confirm how each person became infected, "but we do know that people can acquire the parasite by consuming raw or undercooked snails and slugs," she said.

Heather Stockdale Walden, an assistant professor in the department of infectious diseases and pathology at the University of Florida, said rat lungworm disease has "been endemic in Hawaii for at least 50 years, so it's been there for a while."

Most cases result from consuming, either accidentally or on purpose, raw or undercooked snails and slugs that are infected with the parasite. For example, poorly washed lettuce or other raw produce may contain an unnoticed snail or slug.

Transmission can also occur when people eat infected crabs, shrimp and frogs, though this is believed to be less common, Walden said. There may also be very rare cases of contamination through water.

"Angiostrongylus cantonensis can present differently in adults and children. So usually, in adults, one of the main things that you hear complaint of is a headache," Walden said. She added that adults commonly report neck stiffness, nausea and vomiting.

"In children, it's more the nausea and vomiting, not so much the headache," she said. Children will also run fevers and feel abdominal pain more than adults.

The illness usually lasts between two weeks and two months, and on average, the incubation period is one to three weeks. However, an infection can incubate in only a single day or in six weeks.

People do not become contagious, so they cannot transmit the infection to someone else.

Although the CDC is monitoring the situation in Hawaii, it cannot comment on the investigation, said Amy Rowland, a spokeswoman for the agency's Center for Global Health.

How infections begin

The parasite can fully mature in rats. Garden-variety slugs and snails, which eat rat feces, can serve as intermediate hosts, allowing the parasite to grow to a stage where it is capable of causing infection, though never to full adulthood (and so never capable of reproduction).

"What happens is that the parasite gets into humans -- humans are not the host that it can complete its life cycle in, as opposed to being in a rat -- so when it gets in a human, it can get lost, and it will go to the brain, and it'll stay there," Walden said.