Angiostrongylus cantonensis and Angiostrongylus mackerrasae are parasitic nematodes found in various rat species. In humans A. cantonensis causes the disease angiostrongyliasis which is the most common cause of eosinophilic meningitis worldwide, while A. mackerrasae has shown incidence of disease in animals. Intermediate hosts of these nematodes include a diverse range of molluscs (mainly slugs and snails) which can maintain the infective L3 larval stage of the parasite. Humans, and other large vertebrates are dead-end hosts which become infected following ingestion of molluscs, paratenic hosts or contaminated produce containing infective A. cantonensis larvae. In Australia, recent clinical cases of angiostrongyliasis have been reported in Queensland and New South Wales indicating the need for further research to elucidate the risk of angiostrongyliasis in this region.

In this study, a conventional PCR and a TaqMan assay were compared for their ability to detect Angiostrongylus DNA in DNA extracted from molluscs. Both assays amplified A. cantonensis and A. mackerrasae DNA though the TaqMan assay was more sensitive, detecting an equivalent to one hundredth of a worm larvae. Subsequently, the TaqMan assay was employed for field testing. Sequencing of the 18S rRNA and ITS1 genes of the two Angiostrongylus species revealed little to no difference at these loci (99% identical). A total of 500 molluscs were collected from the Sydney region for DNA extraction. The TaqMan assay detected Angiostrongylus DNA in 3.0% ±0.8% (CI 95%) of molluscs surveyed. This is the first Australian study to survey molluscs using PCR and is the first to report a natural reservoir for Angiostrongylus spp. in Cornu aspersum, which is now thought to be a common intermediate host for Angiostrongylus spp. in Sydney.  This study confirms the presence of the A. cantonensis/mackerrasae complex in Sydney and identifies a ubiquitous natural reservoir (C. aspersum) of A. cantonensis in the area.