WAILUKU, Hawaii — About 200 snails on Maui Island are being tested for rat lungworm disease in an attempt to track the mollusks that caused an unparalleled outbreak on the island this year.
From January to March, Maui tallied six of the state’s 16 cases of the disease, The Maui News reported Sunday.
The island had just two recorded cases before this year, one of which was confirmed in 2010.
Rat lungworms are small parasitic roundworms, or nematodes, that live in rats and snails.
Rats host the worm and pass larvae through their feces, which are eaten by the slugs. Rats then eat the slugs and repeat the cycle. Humans are typically infected after eating raw fruits and vegetables contaminated by the slug.
There is no cure for the disease, which could cause anything from headaches or flu symptoms to seizures or death.
The outbreak has led the manager of the Maui Invasive Species Committee, Adam Radford, and others to further research causes of the disease. Many point to the introduction of more invasive snails.
“It absolutely is a concern,” Radford said. “I do agree to some degree that it’s going out of the public’s mind, but people need to remain vigilant. The parasite has been found throughout Maui so it’s not a problem that’s going away.”
Norine Yeung, malacology researcher at Bishop Museum, is working with Radford and conducting DNA testing of hundreds of Maui’s snails. Results of testing that started in June are in a couple of months.
“We’re pretty much bombarded by invasive land snails,” Yeung said.
The disease first appeared in Hawaii in the 1990s and caused an outbreak on the Big Island in the 2000s. Maui has anecdotal evidence of the illness in 2003 or 2004, Yeung said.
One of the biggest instigators of the outbreak is the “semi-slug,” which has likely caused the majority of cases. About 70 to 80 percent of semi-slugs carry the parasite and can carry at least twice as many nematode larvae per milligram as other mollusk species.
Yeung said the key to combatting the rise in rat lungworm disease is controlling either rat or snail populations. She said it may be easier to fight snails because “rats are too smart.”
“Prevention is so much more helpful,” she said. “If we continue monitoring them, we can kill it before it establishes on an island and save us millions.”