Some wild avian species are reservoirs for Salmonella serotypes, especially Salmonella ser. Typhimurium, concluded Alina Wieliczko and colleagues at Wroclaw University of Environmental and Life Sciences from the results of a recent study.

In their paper in BMC Veterinary Research, they explain that Salmonella species are widespread in the environment, and occur in cattle, pigs and birds, including poultry and free-living birds. In this study, they examined the occurrence of Salmonella in different wild bird species in Poland, focusing on five Salmonella serovars monitored in poultry by the European Union: Salmonella serovars Enteritidis, Typhimurium, Infantis, Virchow and Hadar.

They characterised the variations in these serovars and classified the isolates into species and subspecies of the genus Salmonella by PCR assay. The prevalence of selected virulence genes was also determined.

The researchers collected 64 Salmonella isolates from a total of 1,000 samples from 40 species of wild birds in Poland between September 2011 and August 2013.

The largest numbers of isolates were collected from Eurasian siskin and greenfinch, with 33 per cent positive samples for each.

The collected strains belonged to one of three Salmonella subspecies: enterica (81 per cent), salamae (17 per cent) or houtenae (1.6 per cent).

Eighteen strains belonged to Salmonella Typhimurium (28 per cent), one each to serovars Infantis, Virchow and Hadar.

Wieliczko and colleagues also found that the Salmonella ser. Typhimurium strains varied across the same host species but similarity was observed among strains isolated from the same environment, e.g. the same bird feeder or the same lake.

Reference

Krawiec M., M. Kuczkowski, A.G. Kruszewicz and A. Wieliczko. 2015. Prevalence and genetic characteristics of Salmonella in free-living birds in Poland. BMC Veterinary Research. 11:15.