Incidence of erysipelas in waterfowl in Poland - clinical and pathological investigations.

1. Erysipelas in geese and ducks is an infectious disease causing considerable economic losses in the poultry sector in Poland. The aim of this study was to determine the distribution of erysipelas cases in age groups of geese and in periods of the calendar year and to assess macroscopic lesions in birds infected with Erysipelothrix rhusiopathiae.2. The study used 286 geese and 16 ducks delivered to the laboratory for diagnosis in the years 2019-2021. The birds came from 99 different farms. E. rhusiopathiae from clinical samples were cultured on Columbia blood agar and identified by real-time PCR. Pathological lesions were characterised during anatomopathological examination.3. Distribution of erysipelas cases in age groups of geese and periods of the calendar year differed significantly from the assumed even distribution. Most cases were noted in August and September in birds aged between 11 and 13 weeks. Necropsy of birds infected with E. rhusiopathiae showed anatomopathological lesions characteristic of generalised infection, affecting multiple organs.4. The uneven distribution of erysipelas cases in geese in different age groups and periods of the calendar year suggested that both the age of the birds and climatic conditions are predisposing factors for infection.