The Crayfish Plague in the Czech Republic - Review of Recent Suspect Cases and a Pilot Detection Study

Abstract

There are only very limited reports about the occurrence of the crayfish plague in Czechia. In recent years, mass mortalities of Astacus spp. with symptoms of possible crayfish plague were noticed in three streams in the country -two in Central Bohemia and one in Silesia (2004). Three dead individuals from the last outbreak were examined for the presence of the crayfish plague pathogen, Aphanomyces astaci, by observation of the presence of hyphae in their cuticle and by a PCR-based diagnostic method. In all three cases the detection was positive. Although causes of mass mortalities from two other localities lack such a direct confirmation, the indirect evidence supports the same conclusion. The main potential vector of A. astaci in Czechia is the American spiny-cheeck crayfish Orconectes limosus, widespread in large rivers of the western part of the country and in various isolated standing waters. Using the same molecular method, we investigated the presence of A. astaci in living O. limosus individuals from six localities (three running and three standing waters). The analysis indicated the presence of the pathogen in animals from five out of six investigated Orconectes populations. One of them is present in the stream where two European Astacus species had gone extinct in 1998-9. Our results suggest that the crayfish plague is still present in Czechia, and that populations of O. limosus represent a reservoir for the crayfish plague pathogen, which directly endangers populations of the native crayfish. LA PESTE DES ÉCREVISSES EN RÉPUBLIQUE TCHÈQUE -EXAMEN DES CAS SUSPECTS RÉCENTS ET UNE ÉTUDE PILOTE DE DÉTECTION RÉSUMÉIl n'y a que peu de comptes rendus sur la présence de la peste des écrevisses en République Tchèque. Ces dernières années, la mortalité d'Astacus spp. avec des symptômes de la peste des écrevisses ont été relevés dans trois cours d'eau en République tchèque -deux en Bohème centrale (1998-9) et une en Silésie (2004). On a examiné la présence d'Aphanomcyes astaci, un parasite oomycète causant cette peste, dans trois individus morts lors de la dernière épidémie, utilisant des observations directes du mycélium de l'agent pathogène dans la cuticule, ainsi qu'une méthode de diagnostic à base de PCR. À chaque occasion, les résultats furent positifs. Bien que les causes de mortalité dans deux autres localités manquent de confirmations directes, des évidences indirectes supportent la même conclusion. La peste des écrevisses est traditionnellement transmise par Orconectes limosus, une écrevisse nord américaine.

Recent distribution, population densities and ecological requirements of the stone crayfish (Austropotamobius torrentium) in the Czech Republic

“…Crayfish plague is an ongoing problem in the country, as shown by a massive death of crayfish with plague symptoms in the years (Kozubíková et al, 2006. Unfortunately, the populations at two of the localities monitored in this paper (the lower part of the Úpoř brook and Hýskovský brook) were recently decimated by crayfish plague (Kozubíková et al, 2006).…”

“…The primary such factor is the risk from the oomycete parasite Aphanomyces astaci Schikora, 1906 (i.e., crayfish plague), which is lethal to indigenous European crayfish (Edgerton et al, 2004). In the past, this disease has caused the extinction of some crayfish populations, and local extinctions still occur at present (Kozák et al, 2002;Kozubíková et al, 2006). Apart from the crayfish plague, the Czech stone crayfish population is endangered by predation from the American mink Mustela vison Schreber, 1777 and the European otter Lutra lutra (L., 1758) (Fischer et al, 2009).…”

Distribution of the Invasive Spiny-Cheek Crayfish (Orconectes Limosus) in the Czech Republic. Past and Present

“…On the other hand, there is evidence for at least one case of crayfish plague transmission from Orconectes to the native species in recent years (KOZUBÍKOVÁ et al, 2006). In the Pšovka brook (Central Bohemia, north of Prague) three crayfish species were found in the 1990s, each of them in a different part of the river -Orconectes limosus in the lower reach, Astacus leptodactylus further upstream and the native Astacus astacus in higher reaches of this brook (BERAN, 1995).…”

Temporal variation in the prevalence of the crayfish plague pathogen,Aphanomyces astaci, in three Czech spiny-cheek crayfish populations

“…Oidtmann et al (2006) first established a molecular method suitable for the detection of A. astaci in American crayfish. Subsequently, DNA-based detection was employed on all three of the most important American crayfish invaders in Europe (the signal crayfish: Johnsen et al, 2007;Dunn et al, 2009;Hochwimmer et al, 2009;Skov et al, 2011; the spiny-cheek crayfish: Schulz et al, 2006;Kozubíková et al, 2006Kozubíková et al, , 2008Kozubíková et al, , 2010; and the red swamp crayfish: Aquiloni et al, 2011). The above-mentioned studies were mostly limited in geographical coverage and the number of analysed populations.…”