GREY seal pups that have been infected with forms of the Salmonella bacteria have been found by researchers in Scotland.

Tests on mammals found in Scottish waters or swept ashore discovered that around one in five carried the disease.

Scientists say that the presence of the bacteria raises questions about possible pollution of the marine environment, possible through run-off from farms or sewage being discharged into the water.

Analysis of the different strains found in the pups shows close similarities with those carried by land animals including cattle, and also people.

The study, was led by researchers from the Moredun Research Institute in Edinburgh in collaboration with the Sea Mammal Research Unit.

Others involved in the wide-ranging study included the University of St Andrews, SAC Consulting Veterinary Services, The Scottish Marine Animal Stranding Scheme and the Royal Zoological Society of Scotland.

The team investigated the prevalence and origin of Salmonella in free-ranging and stranded grey seal pups, comparing Salmonella isolated from the grey seals with strains from human cases, livestock, wild mammals and birds.

Dr Johanna Baily of Moredun Research Institute, said: “Finding these Salmonella isolates in large marine mammals along our coastlines raises concerns of land-sea transfer of both human and livestock pathogens.

"We need to know more about how these bacteria have spread to the marine environment and what threat they represent for our native marine mammals”

The team found three types of Salmonella were found, one usually found in cattle, one that is similar to a type found in garden birds, and one which is also found in humans.

Pups that had been swum in the sea were found to be almost four times more likely to carry Salmonella compared to those which had not been in the water.

Dr Ailsa Hall, Director of the Sea Mammal Research Unit, added: “This study gives us an important insight into the factors affecting the survival of grey seal pups and the role that bacterial infection may play.

"Understanding the causes of morbidity and mortality in this species is key to improving our ability to interpret changes in the abundance and distribution of grey seals in the UK”

Dr Geoff Foster of SAC Consulting Veterinary Services, said: “This work expands on current knowledge of the ecology of an important group of pathogenic bacteria for man and animals.

"Our ongoing work with animal livestock, wild mammals and birds, alongside interactions with human health bodies, continues to explore such relationships, which are of significance for animal and public health”.