Parasite found
in isle snails

The public is warned to wash
all vegetables thoroughly after
six meningitis cases arise

Six cases of diagnosed or suspected meningitis caused by a parasite in snails and slugs have prompted state health warnings to wash vegetables thoroughly and avoid eating raw mollusks.

Dr. Sarah Park, deputy chief of the Health Department's Disease Outbreak Control Division, said four cases of infection have been reported on the Big Island, and two cases are pending diagnosis on Oahu.

All of the people affected were seen by doctors and treated but not necessarily hospitalized, she said. One Oahu case was severe, she said.

Two of the Big Island patients are organic farmers, and the third was an adult visiting them, she said: "The visitor knew she bit into a slug in the salad she was eating."

The fourth Big Island victim was a 10-month-old child who was hospitalized on Oahu and discharged, she said.

Parents should be particularly careful that infants do not put a snail or slug in their mouth, Park said.

She said the severe Oahu case probably is meningoencephalitis, a combination of meningitis and encephalitis.

It is not known what the patient was eating, but "rumors are that he was eating snail poke," she said, adding that further investigation is being done.

The worm causing the eosinophilic meningitis infection is called anglostrongylus. It has been documented here in snails and slugs since the 1960s, but doctors have not been required to report the disease, so there is little data on it, Park said.

She said the Health Department began hearing about the recent cases in November. The latest ones were a couple of weeks ago.

"The larva probably causes a spectrum of illness from mild to moderate to severe," she said. "I wouldn't be surprised if milder diseases were occurring we don't hear about."

The Health Department alerted doctors to the recent cases Monday and asked them to report any cases of eosinophilic meningitis.

"The bottom line is we know it's in our snails and slugs, and the best way to prevent getting infected is to wash vegetables -- actually wash and separate each leaf," Park said.

A common theme among cases, she said, is the patients did not wash the vegetables well enough and chopped up a snail into the salad.

Careful washing of vegetables also is important because of exposure to chemicals from pesticides and bacteria from farm animals and implements.

Mollusks such as snails or slugs should be cooked thoroughly to kill the parasites if they are used in any recipe, and people should not eat raw snails or slugs, the Health Department says.

Park said the symptoms can vary and that the infection can be fatal if it is severe enough, but treatments can calm the inflammation.

"The worm tends to like to go to the central nervous system," Park said. "A lot of symptoms would be associated with that."

But it is not something people should be frightened of if they use common sense and wash all their vegetables, she said: "It's not preventative just for parasites. It's for any infectious disease."