Australian Study Shows Angiostrongylus cantonensis Shedding in the Slime of Infected Snails

If this also happens in the Big Island's slugs and snails in the wild, it means that just removing visible debris from garden vegetables is not enough--all such produce should be rinsed and/or peeled well before eating uncooked.

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ABSTRACT

The Prevalence of Angiostrongylus cantonensis/mackerrasae Complex in Molluscs from the Sydney Region

Douglas Chan, Joel Barratt, Tamalee Roberts, Rogan Lee, Michael Shea, Deborah Marriott, John Harkness, Richard Malik, Malcolm Jones, Mahdis Aghazadeh, John Ellis, Damien Stark

Published: May 22, 2015DOI: 10.1371/journal.pone.0128128

Angiostrongylus cantonensis and Angiostrongylus mackerrasae are metastrongyloid nematodes that infect various rat species. Terrestrial and aquatic molluscs are intermediate hosts of these worms while humans and dogs are accidental hosts. Angiostrongylus cantonensis is the major cause of angiostrongyliasis, a disease characterised by eosinophilic meningitis. Although both A. cantonensis and A. mackerrasae are found in Australia, A. cantonensis appears to account for most infections in humans and animals. Due to the occurrence of several severe clinical cases in Sydney and Brisbane, the need for epidemiological studies on angiostrongyliasis in this region has become apparent. In the present study, a conventional PCR and a TaqMan assay were compared for their ability to amplify Angiostrongylus DNA from DNA extracted from molluscs. The TaqMan assay was more sensitive, capable of detecting the DNA equivalent to one hundredth of a nematode larva. Therefore, the TaqMan assay was used to screen molluscs (n=500) of 14 species collected from the Sydney region. Angiostrongylus DNA was detected in 2 of the 14 mollusc species; Cornu aspersum [14/312 (4.5%)], and Bradybaenia similaris [1/10 (10%)], which are non-native terrestrial snails commonly found in urban habitats. The prevalence of Angiostrongylus spp. was 3.0% ± 0.8% (CI 95%). Additionally, experimentally infected Austropeplea lessoni snails shed A. cantonensis larvae in their mucus, implicating mucus as a source of infection. This is the first Australian study to survey molluscs using real-time PCR and confirms that the garden snail, C. aspersum, is a common intermediate host for Angiostrongylus spp. in Sydney.