New research into otter parasites in Somerset

Otter. Copyright Brian Phipps

April 2009. Somerset Wildlife Trust's otter group is partnering a new project that will study in details the affect on otters of two parasites that are infecting many of these elusive creatures.

Somerset Otter Group (SOG) is supporting a three-year PhD study being undertaken by Eleanor Sherrard-Smith at Cardiff University under Dr Elizabeth Chadwick. Eleanor will study the life cycle and effects of the two new parasitic flukes, especially the Bile Fluke, which was first discovered in Somerset in dead otters recovered by the Somerset Otter Group.

Bile Fluke
Most of the otters from lowland rivers in Somerset now carry a greater or lesser burden of this damaging fluke, which can also affect other species, foxes, cats, dogs, and even humans.

The parasites can inflict damage to the gall bladder, potentially causing health problems such as jaundice, emaciation and ultimately cancer of the bile ducts.

James Williams from SOG said: "This research is long overdue, and we hope to support it both financially and in the field. Top level scientists are still baffled about these horrible parasites and we hope this research will answer so many questions. We have searched world literature to find out more about these parasites, but nothing exists."

Somerset otters - Now 70, up from less than 10 twenty years ago
Otter numbers were reduced to single figures in Somerset during the mid-eighties - now numbers are up to around 70. Their numbers have improved due to the strict restrictions placed on pesticides and pollutants and the banning of lead in fuel. But there is still some work to do in this area; chemicals like DDE and PCB that were banned long ago are shown to be still persisting in the environment.

And now otters face new threats - these parasites about which so little is known.

James added: "We can learn so much from how clean our streams and rivers are. And post mortems on dead otters, now carried out in this area by Dr Elizabeth Chadwick at Cardiff, are so important.

Eleanor's PhD will monitor the spread of both parasites by looking at the gall bladders of dead otters and use specimens to develop screening tools. These tools will screen faeces from hosts and potential hosts - such as otters, mink and possibly even dogs and cats. She will also investigate parasite life cycles and population structure using DNA analysis.