The crayfish plague pathogen can infect freshwater‐inhabiting crabs

Abstract

International audienceThe oomycete Aphanomyces astaci is generally considered a parasite specific to freshwater crayfish, and it has become known as the crayfish plague pathogen. Old experimental work that reported transmission of crayfish plague to the Chinese mitten crab Eriocheir sinensis, and the ability of A. astaci to grow in non-decapod crustaceans, has never been tested properly. * We re-evaluated the host range of A. astaci by screening for the presence of A. astaci in two crab species cohabiting with infected crayfish in fresh waters, as well as in other higher crustaceans from such localities. The animals were tested with species-specific quantitative PCR, and the pathogen determination was confirmed by sequencing of an amplified fragment of the nuclear internal transcribed spacer. Furthermore, we examined microscopically cuticle samples from presumably infected crab individuals for the presence of A. astaci-like hyphae and checked for the presence of pathogen DNA in such samples. * Screenings of benthopelagic mysids, amphipods and benthic isopods did not suggest infection by A. astaci in non-decapod crustaceans. In contrast, both studied lake populations of crabs (a native semiterrestrial species Potamon potamios in Turkey, and an invasive catadromous E. sinensis in Sweden) were infected with this parasite according to both molecular and microscopic evidence. * Analyses of polymorphic microsatellite loci demonstrated that A. astaci strains in the crabs and in cohabiting crayfish belonged to the same genotype group, suggesting crayfish as the source for crab infection. * The potential for A. astaci transmission in the opposite direction, from crabs to crayfish, and potential impact of this pathogen on populations of freshwater crabs require further investigations, because of possible consequences for crayfish and freshwater crab conservation and aquaculture

Monitoring of white-clawed crayfish (Austropotamobius pallipes) population during a crayfish plague outbreak followed by rescue

“…Recently, several molecular methodologies have been developed to detect A. astaci directly from infected crayfish tissues (Oidtmann et al, 2006;Vrålstad et al, 2009Vrålstad et al, , 2014Tuffs and Oidtmann, 2011;Grandjean et al, 2014) and have improved the possibilities for screening for this pathogen (Kozubíková et al, 2008;2011b;Aquiloni et al, 2010;Vrålstad et al, 2011;Pârvulescu et al, 2012). These studies confirmed that all of these North American crayfish species can carry crayfish plague and so can freshwater crab species (Svoboda et al, 2014;Schrimpf et al, 2014). In a large scale epidemiology screening in France, Filipova et al (2013) reported that 29 out of 54 populations of P. leniusculus were infected by A. astaci.…”

Tracking the invasion of the red swamp crayfish Procambarus clarkii (Girard, 1852) (Decapoda Cambaridae) in Sicily: a “citizen science” approach

“…Several alien crayfish species are currently known to occur in Europe, and the ever-increasing number of new occurrence records suggests that findings of such species will further increase in the near future (Kouba et al 2014). To date, the only allochthonous crayfish species reported from the wild in Sicilian inland waters is the red swamp crayfish Procambarus clarkii (Girard 1852) (Marrone and Naselli-Flores 2015), which is included in the list of alien species of concern in the EU regulation 1143/2014 on the prevention and management of invasive alien species.…”

“…This could lead to a long-term detrimental effect on the chelonian species, due to the accumulation of harmful concentrations of trace elements and toxic microcystins in the muscles of the crayfish (Naselli-Flores et al 2007, Bellante et al 2015. Last but not least, P. clarkii is the vector of the pathogen of the "crayfish plague", Aphanomyces astaci (Schikora 1903) (Aquiloni et al 2011, Marino et al 2014, an oomycete which proved to be able to infect also the freshwater crab genus Potamon Savigny, 1816 (Svoboda et al 2014). This genus is present in Sicily with the autochthonous species P. fluviatile (Herbst 1785).…”

Black, Grey and Watch Lists of alien species in the Czech Republic based on environmental impacts and management strategy

“…This is the case of the Chinese mitten crab (Eriocheir sinensis), a potential host of a serious pathogen that can be transmitted to freshwater crayfish, i.e., native species of conservation relevance (Svoboda et al 2014). Due to its transient occurrence in the Czech Republic (during periodic migrations only), this species was not listed in group BL3 that includes alien crayfish species with the same capability but established in the country and thus eligible for local management.…”