In vivo efficacy of pyrantel pamoate as a post-exposure prophylactic for rat lungworm (Angiostrongylus cantonensis)

Authors

John Jacob, University of Hawaii at Hilo
Argon Steel, University of Hawaii at Hilo
Lisa Kaluna, University of Hawaii at Hilo
Steven Hess, USDA APHIS National Wildlife Research CenterFollow
Israel Leinbach, USDA APHIS National Wildlife Research Center
Carmen Antaky, USDA APHIS National Wildlife Research Center
Robert Sugihara, USDA APHIS National Wildlife Research Center
Lindsey Hamilton, USDA Agricultural Research Service
Peter Follett, USDA Agricultural Research Service
Kathleen Howe, University of Hawaii at Hilo
Steven Jacquier, University of Hawaii at Hilo
Supakit Wongwiwatthananukit, University of Hawaii at Hilo
Susan Jarvi, University of Hawaii at HiloFollow

Date of this Version

8-1-2022

Citation

International Journal for Parasitology: Drugs and Drug Resistance 19 (2022) 1–5

doi:10.1016/j.ijpddr.2022.04.002

Comments

This is an open access article under the CC BY-NC-ND license

Abstract

Rat lungworm (Angiostrongylus cantonensis) is a neurotropic nematode, and the leading cause of eosinophilic meningitis worldwide. The parasite is usually contracted through ingestion of infected gastropods, often hidden in raw or partially cooked produce. Pharmaceutical grade pyrantel pamoate was evaluated as a post-exposure prophylactic against A. cantonensis. Pyrantel pamoate is readily available over-the-counter in most pharmacies in the USA and possesses anthelmintic activity exclusive to the gastrointestinal tract (GIT). Administering pyrantel pamoate immediately after exposure should theoretically paralyze the larvae in the GIT, causing the larvae to be expelled via peristalsis without entering the systemic circulation. In this study, pyrantel pamoate (11 mg/kg) was orally administered to experimentally infected rats at 0, 2-, 4-, 6-, or 8-h post-infection. The rats were euthanized six weeks post-infection, and worm burden was evaluated from the heart-lung complex. This is the first in vivo study to evaluate its efficacy against A. cantonensis. This study demonstrates that pyrantel pamoate can significantly reduce worm burden by 53–72% (P = 0.004), and thus likely reduce the severity of infection that is known to be associated with worm burden. This paralyzing effect of pyrantel pamoate on the parasite may also be beneficial for delaying the establishment of infection until a more suitable anthelmintic such as albendazole is made available to the patient.