Is rat lungworm disease increasing rapidly?
That depends upon whom you want to believe.
Mindi Clark of Kurtistown, who owns Kalapana Tropicals orchid nursery with her spouse, John, said a standardized medical protocol needs to be developed through research showing what works and what doesn’t.
Affected individuals and their loved ones typically try naturopathic remedies because it seems uncertain what treatments, medicinal or otherwise, actually work — or work best.
Clark said her blood cell counts, though high, were lower than the Hawaii Department of Health cutoff for a rat lungworm disease diagnosis. Clark thinks cases get underreported because rat lungworm is so hard to diagnose.
DOH spokeswoman Janice Okubo said Hawaii follows lab-testing procedures and disease-investigation methods approved by the U.S. Centers for Disease Control and Prevention.
“As a state government organization, the accuracy, reliability, timeliness and integrity of our information is a primary focus, and we take this responsibility seriously,” she said.
But Okubo acknowledged the “many problems” of testing for rat lungworm parasites in humans.
“In the international scientific community, no research group has been able to develop a serologic test for this parasitic infection that is sufficiently specific and sensitive enough to use in field studies — all have important cross-reaction problems,” she said.
As an orchid grower of 30 years, Clark has seen her share of slugs. But she worries most about the recently introduced one.
“The semi-slug is so toxic compared to the Cuban slug,” Clark said.
She said she was sent home with a diagnosis of viral meningitis — without any warnings about the possibility of the highly infectious illness spreading — and given high-dose ibuprofen.
The Hawaii Department of Health reported in 2010 there had been 42 cases of rat lungworm disease from 2007-15, of which 91 percent were on the Big Island.
But Susan Jarvi, a professor in the Department of Pharmaceutical Sciences at the Daniel K. Inouye College of Pharmacy at the University of Hawaii at Hilo, said nobody actually knows how many cases of rat lungworm exist in any given year because the methods of collecting and reporting data aren’t standardized. So it’s not known if the number of cases is actually increasing, as it currently appears.
“I don’t think anybody has a real, accurate number,” Jarvi said.
Hilo Medical Center’s medical director, Dr. Jon Martell, suspects there are many people who perhaps ingest 10 nematode larvae and don’t end up showing symptoms, or just brush off a headache that lasts for a day or two.
He said people who get severe cases of rat lung are the ones who have swallowed greater numbers of nematode larvae. The larvae eventually travel to the brain and eat there, searching for a way to the pulmonary artery — which, in humans, they can’t get to. They eventually die while trying to get to the rat’s lung.
As of Thursday, the Department of Health recorded 13 people had experienced laboratory-confirmed rat lungworm disease statewide in 2017, including 11 people who are residents and two who were visitors.
Of the 11 residents, seven are Big Island residents and four are Maui residents.
“Rat lungworm disease is very uncommon compared to many other diseases such as dengue, Zika, flu, salmonella, however, the disease can be very serious, painful and disabling,” Okubo said.
But Jarvi isn’t sure about the state’s numbers.
“I don’t think they’re entirely accurate,” she said. Hospital discharges data, she said, shows there were 22 cases in 2016 statewide — double the state’s figure. In 2016, the state reported 11 confirmed cases and one probable case. The probable case was on Kauai.
Dr. Francis Tien, retired University of Hawaii chief of infectious diseases, said from Honolulu by phone that incidence is very low.
Tien said he’s thankful none of his 30 or so rat lungworm patients died during his entire medical career. He emphasized that only 10 or 20 cases occur yearly in a state with a population of more than 1 million people.
In all that time, Tien said, “I don’t think the incidence has changed.”
Email Jeff Hansel at jhansel@hawaiitribune-herald.com.
