The rat lungworm, Angiostrongylus cantonensis: intermediate hosts and distribution in Hawaiʻi

Abstract

Eosinophilic meningitis caused by the parasitic nematode Angiostrongylus cantonensis is an emerging infectious disease in tropical/subtropical locations. Humans contract it through ingestion of infected gastropods, the intermediate hosts of A. cantonensis, rats being the definitive hosts. The goal of this thesis is to better understand the host range and geographic distribution of the parasite in Hawaii by: 1) identifying the gastropod species that act as hosts and assessing their parasite loads; 2) ascertaining the distribution of A. cantonensis, modeling the environmental factors influencing it, and predicting habitat suitability throughout Hawaii. Numerous gastropod species (16 of 37 screened) tested positive for A. cantonensis, with a large range of parasite load among and within species. The parasite occurs on five of the six largest islands (not Lanai). A habitat suitability model using mean annual temperature and rainfall predicted that windward areas (higher rainfall) and lower elevations (higher temperatures) were most suitable.