engleski

Prevalence of the pathogen Aphanomyces astaci in freshwater crayfish populations in Croatia

The Oomycete Aphanomyces astaci is an obligate crayfish parasite that co-evolved with American crayfish species and therefore they generally live in a balanced relationship. On the contrary, European native crayfish are highly susceptible to A. astaci and infestation with it causes development of the lethal disease crayfish plague. Until now, five A. astaci strains have been described from freshwater crayfish present in Europe. In this research we aimed to investigate the occurrence of the pathogen A. astaci in Croatian native and non- native crayfish populations, as well as genotype established strains using microsatellite markers and get information on the pathogen epidemiology. Obtained results showed that the pathogen is widespread in both native and non-native crayfish populations. Agent level, when positive, in non-native crayfish was generally low and in native species was higher. Genotyping from microsatellites proved presence of the B (Ps) strain in non-native species Pacifastacus leniusculus, while the A (As) strain was detected from viable native species (Astacus astacus and Austropotamobius torrentium) that are distributed in areas lacking non-native crayfish. The genotype from A. torrentium differed from a typical A (As) by one allele. The strain B (Ps) was identified in native Astacus leptodactylus from the population that co-occurs with P. leniuscuslus. Interestingly, in one A. leptodactylus population presence of both A (As) and B (Ps) strains was found.

crayfish plague; non-native crayfish; native crayfish; genotyping

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