A toddler from East Hawaii is the fifth known victim this year of rat lungworm, a disease that is expected to continue to spread with climate change.

In May the Department of Health reported Oahu’s first case of rat lungworm disease in 2018 in a toddler from Central Oahu. There have been three confirmed pediatric cases so far this year. The DOH said the children likely contracted the disease by accidentally ingesting a slug or snail carrying the a roundworm parasite, which can move throughout the body and cause significant damage to the nerves, brain and spinal cord.

The toddler started exhibiting symptoms in late July and was taken to an emergency room last week and subsequently hospitalized and transferred to an Oahu facility, according to the Health Department, which is investigating possible sources of infection. The child was discharged after several days in the hospital.

The most common symptoms include severe headaches and stiffness in the neck, while the most serious cases can lead to neurological problems, severe pain and long-term disability.

“What we do know is that young children explore the world around them by putting things in their mouths as a natural part of their early development, and this is likely how they became ill,” said DOH spokeswoman Anna Koethe.

In 2017 there were 18 confirmed cases of rat lungworm. Most of them have been on the Big Island.

“There might be tons more, which is one of the reasons we think it’s so important to develop a blood-based diagnostic test,” said Susan Jarvi, a rat lungworm disease expert at the University of Hawaii at Hilo.

The disease is confirmed by a spinal tap, a hospital-based procedure performed by a doctor who draws spinal fluid to test it for the presence of the parasite or its DNA. Most patients are reluctant to have the procedure and therefore are considered probable when exhibiting symptoms of the illness, she said.

“It’s a major concern, especially when you talk to people that have had this disease for five years or more and they’re still suffering the long-term consequences of this infection and there’s really nobody helping them,” she said. “Some of these people have had symptoms for years.”

One victim she knows is still trying to recover from the disease, contracted in 2008, she said.

“We have some of the highest infection of rats and in slugs and snails and that needs to be addressed,” she added. “Nobody’s working on that right now, or not sufficiently.”

The toddler is the third case of rat lungworm disease contracted on the Big Island this year. Maui has had a single case while Oahu has had one toddler victim.

UH researchers said rat lungworm, first detected in Hawaii in 1960, is poised to expand throughout the tropics and mainland as temperatures warm in the future. The disease has been found on five of the six largest islands, where it occurred mostly in warmer and rainier areas.

Rats are the primary hosts, while snails and slugs are considered intermediate hosts that can hide in produce, water catchment systems and garden hoses unbeknownst to the victims who accidentally ingest them.

The Legislature last year granted the Health Department $1 million over two years to help control the spread of rat lungworm. Health officials are working with experts to develop guidelines for schools, farms, food establishments and physicians on how best to prevent the disease.

“The risk of rat lungworm disease exists statewide and we can work together to take steps to prevent it in our communities,” Aaron Ueno, Hawaii island district health officer, said in a news release.

To prevent the spread of rat lungworm, the DOH recommends controlling the population of snails, slugs and rats around homes, gardens and farms. The department also urges residents to use traps and baits and wear gloves when working outdoors. People should also carefully inspect and wash produce, especially leafy greens, and store them in sealed containers.