Seasonal variation of transcriptomic and biochemical parameters of cockles ( Cerastoderma edule ) related to their infection by trematode parasites

Magalhães, Luísa; Montaudouin, Xavier de; Freitas, Rosa; Daffe, Guillemine; Figueira, Etelvina; Gonzalez, Patrice

doi:10.1016/j.jip.2017.05.009

Cited by 9 publications

(4 citation statements)

References 70 publications

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“…On the other hand, sporocyst/host relationship dynamics are much harder to fully understand due to intrinsic low prevalence (e.g. Thieltges et al ., 2008; Magalhães et al ., 2017) or sudden prevalence outbreaks followed by mass mortalities (Jonsson and André, 1992; Thieltges, 2006).…”

Section: Introductionmentioning

confidence: 99%

Monorchis parvusandGymnophallus choledochus: two trematode species infecting cockles as first and second intermediate host

Magalhães¹,

Daffe²,

Freitas³

et al. 2020

Parasitology

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The most deleterious stage of a trematode life cycle occurs in the first intermediate host where the parasite penetrates as a miracidium and asexually multiplicates in sporocysts or rediae. When infection advances, other organs can be occupied with severe effects on host individual health and population dynamics. Existing studies focused on these host/parasite systems are still scarce due to the usual low prevalence in ecosystems. Using cockles (Cerastoderma spp.) and two trematode species (Monorchis parvus and Gymnophallus choledochus) infecting these bivalves as first and second intermediate host, the present work aimed to (1) summarize the most relevant literature and (2) provide new information regarding this host/parasite system, taking advantage of a 21-year monthly database from Banc d'Arguin (France). This long-term monitoring showed that different trematode species display varying host size range preference (6–38 and 31–36 mm for M. parvus and G. choledochus, respectively). The occurrence of coinfection was lower than expected, raising some questions related to parasite interspecific competition. This review improved our understanding of the processes shaping the prevalence and distribution of parasitism. This study highlighted that beyond constant trematode assemblage monitoring, there is a need to identify the main predictors of rediae/sporocysts infection, such as the definitive host dynamics and miracidium infection processes, for future better management of host severe disease and mortality episodes.

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Section: Introductionmentioning

confidence: 99%

Monorchis parvusandGymnophallus choledochus: two trematode species infecting cockles as first and second intermediate host

Magalhães¹,

Daffe²,

Freitas³

et al. 2020

Parasitology

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“…gene expression, phenoloxidase activity or host fecundity) are explored, parasitic state is often defined simply as ‘parasitized’ or ‘unparasitized’ (e.g. Valderrama et al ., 2004 ; Baudrimont et al ., 2006 ; Magalhães et al ., 2017 ). This approach does not accord with evolutionary theory which predicts that at initial infection and low parasite intensity, hosts may invest heavily in reproduction and defence, whereas at high intensity they will direct resources elsewhere (Hurd, 2001 ; Lafferty and Kuris, 2009 ).…”

Section: Discussionmentioning

confidence: 99%

An efficient photograph-based quantitative method for assessing castrating trematode parasites in bivalve molluscs

Brian

Aldridge

2020

Parasitology

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Parasitic castration of bivalves by trematodes is common, and may significantly reduce the reproductive capacity of ecologically important species. Understanding the intensity of infection is desirable, as it can indicate the time that has passed since infection, and influence the host's physiological and reproductive response. In addition, it is useful to know the developmental stage of the trematode, to understand trematode population trends and reproductive success. However, most existing methods (e.g. visually estimating the degree of infection) to assess intensity are approximate only and not reproducible. Here, we present a method to accurately quantify the percentage of bivalve gonad filled with digenean trematode tissue, based on small squashes of gonad tissue rapidly photographed under light microscopy. A maximum of 15 photographs is required to determine the percentage of the whole gonad occupied by trematodes with a minimum of 90% confidence, with smaller mussels requiring fewer. In addition, the stage of trematode infection can be assessed because full sporocysts, spent sporocysts and free cercariae are clearly distinguishable. Although variation exists in the distribution of trematodes in gonad tissue, and thus in the estimate of percentage of the gonad filled with trematodes, this method represents a marked improvement on current coarse assessments of infection which typically focus on binary presence/absence measures. This technique can be used to facilitate a more sophisticated understanding of host–parasite interactions in bivalves, and can inform the conservation and reproductive biology of environmentally crucial species.

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“…This technique has advantages over other non‐destructive assessments of trematode infection. Previously, non‐destructive assessment has been achieved through monitoring of cercarial release in the laboratory (Taskinen, 1998a; Choo & Taskinen, 2015; Magalhães et al, 2017). However, recent work (Magalhães et al, 2017; Magalhães et al, 2019) has shown that this results in estimates of infection rates between 5 and 10 times less than reality, as determined by destructively dissecting the gonad.…”

Section: Discussionmentioning

confidence: 99%

“…Previously, non‐destructive assessment has been achieved through monitoring of cercarial release in the laboratory (Taskinen, 1998a; Choo & Taskinen, 2015; Magalhães et al, 2017). However, recent work (Magalhães et al, 2017; Magalhães et al, 2019) has shown that this results in estimates of infection rates between 5 and 10 times less than reality, as determined by destructively dissecting the gonad. There is the possibility for cercarial monitoring to reach high accuracy: at elevated temperatures, Choo & Taskinen (2015) showed that this technique could reliably diagnose infection.…”

Section: Discussionmentioning

confidence: 99%

A rapid, non‐destructive method for sampling castrating parasites in endangered bivalve molluscs

Brian

Aldridge

2020

Aquatic Conservation

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Bivalves are important ecosystem engineers, and there is emerging evidence that many species are afflicted with castrating parasites. Understanding the prevalence of these largely overlooked parasites is crucial in understanding the fundamental biology of bivalves, informing conservation efforts, and providing a wider understanding of host–parasite dynamics. Current techniques to assess the presence of parasites are destructive, making them untenable for endangered or protected populations. This article presents a non‐destructive method of sampling bivalve molluscs (Anodonta anatina) to detect castrating trematodes. Gonadal fluid is removed with a hypodermic needle from bivalves in situ and analysed in a laboratory setting without removing the mollusc from the field; this sampling mechanism has previously been shown not to harm the mollusc. A single 50 μl sample is sufficient to detect both the presence and developmental stage of the trematode with greater than 95% reliability, with all but the lightest infections visible. We recommend that this technique should be used to enhance knowledge on host–parasite dynamics in bivalves, and inform sensible conservation for threatened species.

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Seasonal variation of transcriptomic and biochemical parameters of cockles ( Cerastoderma edule ) related to their infection by trematode parasites

Cited by 9 publications

References 70 publications

Monorchis parvusandGymnophallus choledochus: two trematode species infecting cockles as first and second intermediate host

Monorchis parvusandGymnophallus choledochus: two trematode species infecting cockles as first and second intermediate host

An efficient photograph-based quantitative method for assessing castrating trematode parasites in bivalve molluscs

A rapid, non‐destructive method for sampling castrating parasites in endangered bivalve molluscs

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