Franny Brewer, program manager at the Big Island Invasive Species Committee, has been actively educating the community about the dangers of rat lungworm, a tropical parasite that can cause serious health issues in humans.
The parasite, known scientifically as Angiostrongylus cantonensis, primarily resides in the pulmonary arteries of rats, from where it can be shed in their feces.
When these feces are ingested by slugs or snails, the parasite’s larvae hatch and can enter the food chain, ultimately posing a risk to humans.
Recent research has revealed that a variety of species, including 32 types of freshwater prawns, crayfish, crabs, flatworms, fish, and even certain reptiles and mammals can carry the rat lungworm parasite.
This study, conducted by the University of Hawaiʻi at Mānoa and the University of London, demonstrated that multiple animals can contribute to the spread of this concerning disease.
Though the East side of the Big Island has seen a higher prevalence of infections, cases have been documented throughout Hawaiʻi, emphasizing the need for comprehensive awareness among both residents and visitors.
“Every resident and visitor should be aware of rat lungworm and know the basics of protecting themselves from it,” Brewer emphasized, highlighting the importance of community education in mitigating risks.
To effectively control the populations of pests that facilitate the rat lungworm life cycle, measures such as deploying poisonous bait, trapping, and using repellents are essential.
Brewer recommends an innovative method she calls “slug jugs,” a mixture of six parts water to one part salt, which can kill slugs and snails along with the parasites they may carry.
She suggests dedicating time during the rainy season to actively hunt for slugs at night, using gloves and chopsticks or tongs to collect them and dispose of them in the slug jug.
Another critical preventative step is ensuring that all raw vegetables and fruits are thoroughly cleaned before consumption.
Inadvertently consuming slugs or snails hidden in leafy greens can lead to infection, which starts with nonspecific symptoms.
Individuals who contract the parasite may initially experience nausea, vomiting, and abdominal pain, which can evolve into severe headaches and neurological issues over time.
The most severe consequence of the infection is eosinophilic meningitis, as the larvae migrate into the central nervous system, and in rare cases, it can lead to coma or death.
Children infected with the parasite may show signs of irritability, along with fever and developmental regression.
In an effort to promote awareness and explore solutions, Dr. Susan Jarvi established the Hawaiʻi Island Rat Lungworm Working Group, which conducts research and educational initiatives.
With funding from the Hawaiʻi Community Foundation, the group has created an educational program sanctioned by the Department of Education to train teachers and educate students on the risks associated with rat lungworm.
As the group explores different methodologies, including a potential “veggie wash” to minimize infection risks, Jarvi advises the use of potable water while cooking vegetables for safety.
While research continues, Brewer emphasizes the importance of adhering to preventative measures for everyone’s safety.
She recommends keeping commonly available over-the-counter pinworm medicine, specifically pyrantel pamoate, at home as it may reduce the risk of serious disease if taken shortly after accidental ingestion.
Despite limited data regarding the medication’s efficacy, Hilo Medical Center has recommended its use along with albendazole, an anti-worm drug.
“If there are no parasites in the body, the medicine causes no harm, so I always try to encourage people to keep a box at home just in case,” Brewer advised.
She encourages individuals to advocate for themselves when seeking medical attention, especially given the novelty of rat lungworm disease among some healthcare professionals less familiar with tropical illnesses.
The Hawaiʻi Department of Health issued a medical advisory on July 15, urging increased vigilance among clinicians due to the disease’s nonspecific early symptoms, which could develop into severe conditions over time.
In 2024, there were seven laboratory-confirmed cases of rat lungworm, primarily in Hawaiʻi County, with a further case reported in 2025.
Experts believe that the actual number of infections may be higher, as diagnosing the disease poses challenges.
As an illustrative case, a visitor contracted rat lungworm late in 2024 after consuming unwashed greens during a hike on the Big Island, which led to a prolonged hospital stay.
“This isn’t just a local issue; visitors are at equal risk statewide,” said Dr. Lorrin Pang, an epidemiologist with the Department of Health.
The health department stresses the importance of simple precautions like thoroughly washing produce and avoiding raw slugs or snails to prevent infections.
A new RT-PCR test implemented at the Hawaiʻi State Laboratories Division enables quicker detection of the parasite in cerebrospinal fluid, providing hope for improved patient outcomes.
The Department of Health advises everyone to inspect all fruits and vegetables under running potable water, while also recommending cooking susceptible foods to a temperature of at least 165°F.
Consumers are encouraged to freeze vegetables for a minimum of 24 hours and to handle potential host animals with gloves.
Homeowners are further advised to take steps to rodent-proof their properties and to set traps to decrease rat populations.
As new cases emerge, the Department of Health urges individuals to seek immediate medical attention for any unusual symptoms and to report them to their hotline at 808-586-4586.
image source from：bigislandnow
