# Development of a TaqMan qPCR Method for Detecting Angiostrongylus cantonensis (Rhabditida: Angiostrongylidae) Infection in Snails from Hainan Province, China

## TL;DR

A new qPCR method was developed to detect a parasitic worm in snails, offering a more sensitive and non-invasive alternative to traditional methods.

## Contribution

A novel TaqMan qPCR assay targeting a new genomic region of A. cantonensis was developed and shown to be more sensitive than existing methods.

## Key findings

- The qPCR assay detected A. cantonensis in 75 out of 120 A. fulica snails, significantly higher than traditional microscopy.
- A. cantonensis DNA was detected in snail mucus, suggesting non-invasive diagnostic potential.
- C. hainanensis was identified as a new host of A. cantonensis in Hainan Province.

## Abstract

Angiostrongylus cantonensis (A. cantonensis) is the primary causative agent of human angiostrongyliasis and is widely distributed in Southeast Asia and China, with increasing reports from the Americas. Achatina fulica (A. fulica), Pomacea canaliculata (P. canaliculata), and slugs constitute established intermediate hosts of A. cantonensis, whereas Camaena hainanensis (C. hainanensis) has been newly reported as a host species in Hainan. A TaqMan quantitative PCR (qPCR) method assay targeting a novel genomic region of A. cantonensis was developed to detect infection in 150 snails collected from Hainan Province, China. The assay was employed to detect the parasite larvae across various snail tissues (lung sac, mucus, and foot), and its performance was compared with conventional lung sac microscopy. Out of the 120 A. fulica examined, 75 tested positive using the qPCR assay, yielding a significantly higher detection rate than lung-sac examination (p < 0.05). Significant differences were also observed in the positivity rates across the three snail tissues (lung sac, mucus, and foot) (p < 0.05), with the lung sac showing the highest rate of infection. Importantly, the detection of A. cantonensis DNA in snail mucus highlights its potential for development as a non-invasive diagnostic sample. Additionally, C. hainanensis was identified as a new host of A. cantonensis in Hainan, suggesting its possible contribution to parasite transmission. The newly developed qPCR assay demonstrated superior sensitivity (reflected by lower Ct values) compared with previously published TaqMan qPCR methods. The established qPCR method provides a sensitive and non-invasive tool for detecting A. cantonensis in snails, and can be applied for monitoring and early warning of parasite prevalence and transmission.