UH Hilo research shows risk of RLW disease greater than expected; legislators vow to aid in fight

A University of Hawaiʻi at Hilo research group supported by Hawai‘i Island legislators is urging more control measures be taken to lower the risks of the spread of rat lungworm (RLW) disease.

Findings of a study headed by the Rat Lungworm Working Group at the UH Hilo Daniel K. Inouye College of Pharmacy (DKICP) are described in a paper entitled “High prevalence of Angiostrongylus cantonensis (rat lungworm) on eastern Hawai‘i Island: a closer look at life cycle traits and patterns of infection in wild rats” published in the journal PLOS ONE.

“Our study showed almost 94 percent of the rats in the Hilo area are infected with RLW,” said Susan Jarvi, director of the working group who has been researching the progress of the disease for more than six years. 

More than 30 other countries report data on RLW, including Australia, Brazil, Thailand and China. Jarvi suggests that due to the lack of diagnostic tools and difficulty in diagnosis, the disease may be underreported. Her group has been adding to the scientific evidence that gives legislators in Hawai‘i the proof they need to become more involved.

“Hawai‘i is able to take the lead globally on assessing the effects of this debilitating disease thanks to this scientific evidence from UH Hilo,” said Senator Kai Kahele, who represents Hawai‘i Senate District 1, which includes Hilo. “The first step in conquering a threat is in knowing the enemy. We can get ahead of the terrifying risks, but these results certainly show the urgency for more research.”

RLW disease is a parasitic infection that reproduces in rats and is transferred to slugs and snails, which can, if ingested intentionally or not, infect people. While symptoms can be mild and flu-like, there have been cases that have resulted in long-term disability and even death.

“UH Hilo continues to support Dr. Jarvi’s efforts to safeguard public health through her research on the system of this disease,” noted UH Hilo Interim Chancellor Marcia Sakai. “We are exploring alternatives with state agencies that will continue to fund this important research, which reflects our commitment to help maintain the health of the community.”

Researchers in this study examined a total of 545 wild rats from multiple sites in the South Hilo District of east Hawai‘i Island. Through evaluation of multiple stages and locations of development of the infection with A. cantonensis, they were able to determine prevalence, and examine patterns of infection. The purpose was to determine how these data can be used to improve risk assessment and guide research development to better prevent and control human infection.

“Defeating this threat to our islands is essential to perpetuating our way of life,” said Representative Chris Todd, who represents Hilo in the Hawai‘i State House of Representatives. “I believe in the research being done at UH Hilo; their work will help us ensure a healthy future for our keiki – we, as a legislature, need to do more to support their mission.”

DKICP and the Hawai‘i Community Foundation – Medical Research supported research in this study. Authors were from DKICP: Jarvi, Stefano Quarta, Steven Jacquier, Kathleen Howe, Deniz Bicakci, Crystal Dasalla, Noelle Lovesy, Kirsten Snook and Robert McHugh; and Chris N. Niebuhr from the U.S. Department of Agriculture Animal Plant Health Inspection Service's National Wildlife Research Center, Hawai‘i Field Station in Hilo.

“The clear and present danger of this difficult-to-eradicate disease warrants increased measures to control its spread in both snails, slugs and rodents,” Jarvi said. “Only by deliberate management can we hope to protect human and animal populations.”