Latest DKICP research supports use of additional rat lungworm treatment

Rat lungworm disease is an ongoing threat to many parts of the world, including in Hawaiʻi, where it is considered a hotspot in the United States. Recent research conducted by Dr. John Jacob, a 2022 Doctoral graduate of DKICP and current post-doctoral researcher in the Jarvi lab, supports the use of antiparasitics as a safe and effective therapy for the treatment of the disease.

The treatment of rat lungworm disease has historically been controversial, particularly with the use of antiparasitic drugs such as albendazole. Many members of the clinical Hawaiʻi community have concerns that killing the parasite using albendazole could theoretically trigger an intense inflammation in the brain, which would lead to further complications, explains Jacob.

“We conducted the most extensive literature survey to date on the safety and efficacy of albendazole and other antiparasitic drugs, and found that over 90 percent of the published research supports their safe and effective use for the treatment of rat lungworm disease, with strong recommendations for the concurrent use of steroids to reduce inflammation,” says Jacob. The same team, working under the direction of DKICP Professor Sue Jarvi, had previously identified pyrantel pamoate, a widely used, affordable, over-the-counter antiparasitic drug, commonly known as “pinworm medicine,” to be a potential post-exposure prophylactic for rat lungworm disease. “If you saw a slug or snail in your meal or accidentally ate it, then immediately taking pyrantel pamoate may help reduce the number of parasites getting into the blood, thus reduce the severity or even prevent the infection,” explains Jacob.

Currently, there are no other precautionary treatment methods for rat lungworm disease. In 2021, the Jarvi lab, in collaboration with the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) in Hilo, conducted an experimental rat study to verify the effectiveness of this pinworm medicine on rat lungworm. They found that the administration of pyrantel pamoate hours after ingestion of third-stage larvae could reduce the number of worms causing the infection by 53% to 72% and may also reduce the severity associated with the number of worms involved in the infection. This study concluded that pyrantel pamoate can be considered an effective post-exposure prophylactic against rat lungworm disease, by reducing the severity of the disease as well as delaying the infection, providing more time for the administration of antiparasitic drugs like albendazole.

Based on these findings, physicians at Hilo Medical Center now recommends the immediate use of pyrantel pamoate after a known ingestion of a slug or snail, which could possibly be infected with rat lungworm.