New research released Monday shows that almost 94 percent of rats in the Hilo region are infested with Angiostrongylus cantonensis, the parasitic nematode that causes rat lungworm disease in humans.
The study, the largest of its type conducted in Hawaii, sheds light on how common the disease is in rats, said lead author Sue Jarvi, a professor at the University of Hawaii at Hilo.
Jarvi’s team studied 545 rats caught in live traps from 11 sites in East Hawaii in collaboration with the state Department of Health’s Vector Control Branch and the U.S. Department of Agriculture’s Animal Plant Health Inspection Service.
Hilo lawmakers responded to the study Monday by calling for more research funding after the Rat Lungworm Working Group at the UH-Hilo Daniel K. Inouye College of Pharmacy published its results.
State Rep. Chris Todd said in a telephone interview that he thinks the Legislature will act next session to fund rat lungworm research.
“You’re going to see a greater sense of urgency at the Legislature this year,” he said.
State Sen. Kai Kahele said in a statement that the first step in conquering a threat is to know the enemy.
“These results certainly show the urgency for more research,” he said.
East Hawaii is considered the epicenter of rat lungworm disease in humans, according to the study.
Jarvi said rats near Hilo Harbor and Hilo International Airport are especially worrisome because some end up getting transported to the mainland and other countries, potentially exporting rat lungworm.
Researchers want to develop a way to diagnose rat lungworm in humans using a blood test.
The Centers for Disease Control and Prevention, UH-Hilo and researchers in Thailand are all reviewing parasites that were collected, checking potential proteins, Jarvi said.
She said the three options from those studies will be tested to see which might best be used to help diagnose rat lungworm in humans.
Humans get rat lungworm disease by accidentally eating or drinking foods contaminated with snails or slugs carrying parasitic larvae from rat droppings.
Although some humans exhibit only mild symptoms if they get rat lungworm disease, others can experience brain damage, coma or even death. The more larvae a person consumes, the worse the symptoms.
The DOH said rat lungworm symptoms can include headache, fever, stiff neck, tingling or painful feelings in the skin or extremities.
Public service announcements from the DOH advise consumers to thoroughly wash produce, kill slugs and snails on their property, control rats and cook foods.
Jarvi said washing produce is better than not washing it. But many experts such as Jarvi advise cooking any locally grown produce before eating it — or freezing for 48 hours.
The peer-reviewed study was published in the scientific journal PLoSOne and titled “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 (Rattus spp.).” It was funded by the College of Pharmacy and the Hawaii Community Foundation.
Email Jeff Hansel at jhansel@hawaiitribune-herald.com.