Efficacy of X-Ray Phytosanitary Irradiation on the Infectivity and Reproduction of Angiostrongylus cantonensis in Experimentally Infected Rats

Authors

Susan I. Jarvi, University of Hawaii at HiloFollow
Lisa M. Kaluna, University of Hawaii at Hilo
Steven C. Hess, United States Department of Agriculture, Animal Plant Health Inspection Service, National Wildlife Research Center, Hawaii Field Station
Lindsey Hamilton, United States Department of Agriculture, Agricultural Research Service, Daniel K. Inouye Pacific Basin Agricultural Research Center
Carmen Antaky, United States Department of Agriculture, Animal Plant Health Inspection Service, National Wildlife Research Center, Hawaii Field Station
Robert T. Sugihara, United States Department of Agriculture, Animal Plant Health Inspection Service, National Wildlife Research Center, Hawaii Field Station
Israel L. Leinbach, United States Department of Agriculture, Animal Plant Health Inspection Service, National Wildlife Research Center, Hawaii Field Station
Yaeko Tagami, University of Hawaii at Hilo
Argon Steel, University of Hawaii at Hilo
Kathleen Howe, University of Hawaii at Hilo
Steven Jacquier, University of Hawaii at Hilo
Forrest Cookman, University of Hawaii at Hilo
Jocelyn Diaz, University of Hawaii at Hilo
John Jacob, University of Hawaii at Hilo
Peter Follett, United States Department of Agriculture, Agricultural Research Service, Daniel K. Inouye Pacific Basin Agricultural Research Center

Document Type

Article

Date of this Version

2024

Citation

American Journal of Tropical Medicine and Hygiene (2024) 110(4): 691–699

doi: 10.4269/ajtmh.23-0570

Comments

United States government work

Abstract

Angiostrongylus cantonensis is a globally distributed nematode and the leading cause of eosinophilic meningitis in humans. As a global hotspot for this disease, Hawaii’s agricultural exports may be contributing to the spread of A. cantonensis. Phytosanitary irradiation doses of 150 or 400 Gy provide quarantine security against multiple insect pests. We evaluated the in vitro and in vivo effects of phytosanitary irradiation on infectious, third-stage A. cantonensis juveniles. In vitro experiments directly exposed juveniles to irradiation doses ranging from 200 to 1,000 Gy. Results showed low mortality and no dose response across all treatments 27 days post-irradiation. In vivo studies isolated larvae from wild-caught Parmarion martensi after exposure to x-ray irradiation at doses of 0, 150, and 400 Gy and infected them into laboratory rats. Fourteen rats were assigned to each treatment and infected with 50 larvae from their assigned irradiation dose. Results at 3 and 6 weeks post-infection demonstrated a significant negative dose response in regard to the number of juveniles that migrated to the brain and adults found in the pulmonary artery. No irradiated juveniles that grew into adults were able to produce eggs. These findings indicate that x-ray irradiation does not result in the direct mortality of A. cantonensis juveniles; however, it does affect the infectivity and reproduction of A. cantonensis within its definitive host, the rat. Phytosanitary irradiation at doses ≥ 150 Gy appears to be an effective means of preventing the establishment of viable populations of A. cantonensis, thus reducing the potential for global spread due to agricultural exports from Hawaii.