AbstractAngiostrongylus cantonensis (Rat Lungworm) is a major pathogen of Eosinophilic Meningitis in humans worldwide. Angiostrongylus cantonensis generally completes its life-cycle in two hosts: the rats as definitive and the gastropods as intermediate hosts. Among the wide range of intermediate hosts is the critically invasive Pomacea canaliculata (Golden apple snails), which have caused numerous outbreaks of neuroangiostrongyliasis worldwide, especially China and Taiwan. While there have been numerous surveys on the prevalence of Angiostrongylus cantonensis larvae in P. canaliculata in China, there are an inadequate number of studies in Taiwan. This review gives an overview of the current status of A. cantonensis prevalence and infection in general, along with focusing on the status and developments regarding neuroangiostrongyliasis in Taiwan. Additionally, we investigate the implications of a well-known invasive vector of A. cantonensis, Pomacea spp., and its effects on disease transmission to humans. Results show that P. canaliculata has been the source of approximately 15.5% infections in Taiwan. Furthermore, due to rapidly growing invasive freshwater snail populations (specially Pomacea spp.), indirect transmission through water cannot be neglected. Thus, as a precautionary measure, we suggest environmental DNA based monitoring should be implemented to detect parasites. Keywords: Foodborne disease; invasive species; Angiostrongylus cantonensis; Pomacea spp.; neuroangiostrongyliasis; TaiwanIntroductionAngiostrongylus cantonensis (the rat lungworm), the primary causative agent for several outbreaks of eosinophilic meningitis in humans (Tseng et al., 2011), was first described by Chen (1935) based on the worms collected from the pulmonary arteries of infected rats in Guangzhou, China. The first human infection by this nematode was reported in Taiwan, by Nomura and Lin, 10 years later (Beaver and Rosen, 1964). Angiostrongylus cantonensis infection typically presents as eosinophilic meningitis; however, other manifestations in the form of ocular angiostrongyliasis, encephalitis, and radiculomyelitis have also been reported. Primary symptoms include acute headaches, eosinophilia in the blood and cerebrospinal fluid (CSF), and other symptoms ranging from fever, hyperesthesia, paresthesia, nausea, vomiting and in some rare cases even coma and death (Cowie et al., 2022). There is an additional risk of developing chronic sequelae, which is majorly debilitating. Definitive diagnosis of this infection has proved to be challenging; given visual detection of parasite in patient samples is rare; and the amplification of the ITS1 region of the parasite DNA from the patient’s CSF has a detection rate of merely 65.3% (Jarvi et al., 2023). Hence, spreading awareness for prevention is just as important as finding a cure.Angiostrongylus cantonensis nematode is a parasite, its synanthropic definitive and intermediate hosts being rodents (particularly Rattus spp.) and a diverse range of gastropods, respectively; however, animals such as shrimp, frogs, and lizards can act as paratenic hosts (Turck et al., 2022) (Figure 1). Consumption of such hosts have given rise to further cases and outbreaks ofAngiostrongylus cantonensis infection in humans in several countries, including Taiwan (Tseng et al., 2011), Thailand (Eamsobhana, 2014), China (Lv et al., 2009), Brazil (Morassutti et al., 2014), USA (Cowie et al., 2017), Vietnam (McBride et al., 2017), Australia (Barratt et al., 2016), and India (Pandian et al., 2023). A number of cases have occurred in travelers to endemic areas, where consumption of exotic dishes and contaminated foodstuffs result in infection (Federspiel et al., 2020), which highlights the necessity for further awareness about this disease and its causative agent. Indeed, there are concerns as to the extent of infection the rat lungworm can inflict upon humans, where cases have shown presence of the parasite in the lungs of human patients (Prociv et al., 2000). Nevertheless, as the presence ofAngiostrongylus cantonensis in human feces have not yet been identified, hence the spread of Angiostrongylus cantonensisdepends largely on its natural hosts; rats and gastropods.

Pritam Banerjee1, 2, Kathryn A. Stewart3, Caterina M. Antognazza4, Ingrid V. Bunholi5, Kristy Deiner6, Matthew A. Barnes7, Santanu Saha8, Héloïse Verdier9, Hideyuki Doi10, Jyoti Prakash Maity2, Michael W.Y. Chan1, Chien Yen Chen2*1Department of Biomedical Sciences, Graduate Institute of Molecular Biology, National Chung Cheng University, 168 University Road, Ming-Shung, Chiayi County 62102, Taiwan2Department of Earth and Environmental Sciences, National Chung Cheng University, 168 University Road, Ming-Shung, Chiayi County 62102, Taiwan.3 Institute of Environmental Science, Leiden University, 2333 CC Leiden, The Netherlands4 Department of Theoretical and Applied Science, University of Insubria, Via J.H. Dunant, 3, 21100, Varese, Italy5 Department of Biology, Indiana State University, Terre Haute, IN 47809, USA6 Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CH-8092 Zurich, Switzerland7 Department of Natural Resources Management, Texas Tech University, Lubbock, TX USA8Post Graduate Department of Botany, Bidhannagar College, Salt Lake City, Kolkata 700064, India9Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, Villeurbanne, France10Graduate School of Information Science, University of Hyogo, 7-1-28 Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, JapanAbstract Plant-animal interactions (PAI) represent major channels of energy transfer through ecosystems, where both positive and antagonistic interactions simultaneously contribute to ecosystem functioning. Monitoring PAI therefore increases understanding of environmental health, integrity and functioning, and studying complex interactions through accurate, cost-effective sampling can aid in the management of detrimental anthropogenic impacts. Environmental DNA (eDNA)-based monitoring represents an increasingly common, non-destructive approach for biomonitoring, which could help to elucidate PAI. Here, we focused our foundation to discuss the potential of eDNA in studying PAI on the literature existing from 2009 to 2021 using a freely accessible web search tool. The search was conducted by using key words involving eDNA and PAI, including both species-specific and metabarcoding approaches, recovering 43 studies. We summarise advantages and current limitations of such approaches, and we offer research priorities that will potentially improve future eDNA-based methods for PAI analysis. Our review has demonstrated that numerous studies exist using eDNA to identify PAI (e.g., pollination, herbivory, mutualistic, parasitic relationships), and although eDNA-based PAI studies remain in their infancy, to date they have identified higher taxonomic diversity in several direct comparisons to DNA-based gut/bulk sampling and conventional survey methods. Research into the influencing factors of eDNA detection involved in PAI (e.g., origin and types, methodological standardization, database limitations, validation with conventional surveys, and existing ecological models) will benefit the growth of this application. Thus, implementation of eDNA methods to study PAI can particularly benefit environmental biomonitoring surveys that are imperative for biodiversity health assessments.

In a recent paper, “Environmental DNA: What’s behind the term? Clarifying the terminology and recommendations for its future use in biomonitoring”, Pawlowski et al. argue that the term eDNA should be used to refer to the pool of DNA isolated from environmental samples, as opposed to only extra-organismal DNA from macro-organisms. We agree with this view. However, we are concerned that their proposed two-level terminology specifying sampling environment and targeted taxa is overly simplistic and might hinder rather than improve clear communication about environmental DNA and its use in biomonitoring. Not only is this terminology based on categories that are often difficult to assign and uninformative, but it ignores what is in our opinion the most important distinction within eDNA: the type of DNA (organismal or extra-organismal) from which ecological interpretations are derived.