Rat Lungworm Update

Nov 23, 2017

Credit Wikimedia Commons

The number of rat lungworm cases confirmed by the State Department of Health has been growing since the department began tracking them a decade ago.  For the first 8 years, there were 65 cases in the state.  But numbers are increasing – 12 last year, and 17 so far in 2017.  Most of the cases have been on the Big Island—65 out of 78. But this year there have also been 6 cases on Maui and one on O'ahu. HPR contributing reporter Sherry Bracken spoke with a pair of medical professionals working on the spread of rat lungworm on the Big Island, and has an update.

Dr. Jon Martell of Hilo Medical Center has treated more cases of rat lungworm than anyone else in the state. He's seen 21 cases in the past year that are likely to be rat lungworm—or angiostrongylus.

"We now stratify the severity of the disease based on the symptoms and we break our patients down into mild, moderate, severe.  Our treatment course is somewhat different for the three categories."

The treatment includes a combination of steroids and the anti-parasitic, albendazole. Long term impacts of rat lungworm can include neurological impairment and crushing pain.

"One of the characteristics of the pain is it's really not responsive to ordinary pain treatments."

Rat lungworm is transmitted primarily by rats, slugs and snails. Doctors say the current best test is a spinal tap, but it's not always definitive. Dr. Susan Jarvi of UH Hilo College of Pharmacy is working to develop a blood test. She's been researching the condition since 2011.

"We've been working with a colleague in Thailand, and she's been working in rat lungworm diagnostics for well over a decade.  Her lab has developed the most reliable antibody-based test available at this time. Over the last two years, we've run a study in East Hawai'i, 435 participants." 

Dr. Jarvi also sent 1,500 worms to the Centers for Disease Control, and they're isolating the antigens in yet a different way.  Because of potential differences between Thailand rat lungworm and Hawai'i rat lungworm, Dr. Jarvi plans to do a three-way test, with the CDC, to help determine which test is best. Jarvi is also looking at how it's contracted, via produce and possibly catchment water.

Funding for research remains a challenge, but outreach efforts have increased. A recently established Puna Support Group will meet monthly. Hilo Medical Center has created a fact sheet for emergency room doctors, and with College of Pharmacy, has created educational materials for adults and children.