J. Pajdak

Presence of ail and ystB genes in Yersinia enterocolitica biotype 1A isolates from game animals in Poland

The pathogenicity of Yersinia enterocolitica is associated with the presence of plasmid and chromosomal virulence genes. Strains belonging to biotype 1A do not possess pYV plasmids, often harbour the ystB gene and usually lack the ail gene, which is the main virulence marker for Y. enterocolitica. The simultaneous presence of ail and ystB is uncommon. In this study, 21/218 (9.6%) biotype 1A Y. enterocolitica isolates from rectal swabs of wild boar (Sus scrofa; n = 18), red deer (Cervus elaphus; n = 2) and roe deer (Capreolus capreolus; n = 1) in Poland harboured both ail and ystB genes.

Intracohort cannibalism and methods for its mitigation in cultured freshwater fish

Abstract Cannibalism is a common phenomenon that occurs in over 30 fish families. Most of the species are valuable objects of aquaculture and cannibalism is highly undesirable. Cannibalism is an aggressive behaviour, which can be caused by stress induced by various population and environmental factors and can occur in two main forms: early larval and late juvenile (or adult). Each of these forms can lead to severe losses of stock. Losses are caused not only by fish eating each other, but also by an increase in the number of infections (the result of body surface damage). It is important to understand the phenomenon of cannibalism in order to properly prevent, diagnose and reduce it. The main aim of this study was to present and examine some of the well-examined methods of cannibalism mitigation. Most of the methods consist of creating rearing conditions similar to natural conditions and to reduce stress. Moreover, because of large interspecies differences, similar methods can result in different effects depending on the species. Additional studies are needed to better understand the biology of each cultured species with particular emphasis on the impact of domestication, as well as to improve fish rearing conditions.

Characterization of Yersinia enterocolitica strains potentially virulent for humans and animals in river water.

The aim of this study was to isolate and identify potentially pathogenic strains of Yersinia enterocolitica in water samples collected from the upstream section of the Drwęca River in Poland.