Insect bite hypersensitivity (summer eczema) in Icelandic horses in Icelandic horses



 

Staff: Sigurbjörg Þorsteinsdóttir and Vilhjálmur Svansson senior scientists, Lilja Þorsteinsdóttir PhD student, Sigríður Jónsdóttir MSc student and Heiða Sigurðardóttir MSc student, Mareike Heimann Dr.Med.Vet student.

Co-workers: Valgerður Andrésdóttir and Ólöf Sigurðardóttir Institute for Experimental Pathology, University of Iceland, Keldur. Eliane Marti, Jozef Janda and Eman Hamza and Anna Schaffartzik Dept. of Clin. Vet. Med. Vetsuisse Faculty University of Berne Switzerland, Reto Crameri SIAF, Davos, Switzerland, Einar Mäntylä ORF Genetics, Einar Torfason Department of Virology the University Hospital, Sigríður Björnsdóttir, Chief veterinary office, Selfoss, Iceland, Kristinn Guðnason the Horse farmers association and Ágúst Sigurðsson the rector of the Agricultural University, Hvanneyri.

Insect bite hypersensitivity (IBH) or summer eczema is a recurrent seasonal allergic dermatitis of horses based on an IgE-mediated reaction to biting flies of the genus Culicoides and, in some cases, Simulium. Although all breeds of horses can be affected, this condition is especially prevalent in horses born in Iceland and exported to the continent. Since the year 2000, there has been an ongoing collaborative research project on IBH between scientists at Keldur and the University of Berne, Switzerland. The aim of the project is to:

  • find and characterise the allergens causing IBH
  • analyse the immune response that leads to IBH in horses
  • develop an efficient specific immunotherapy.

The past years we have been working on isolating the initiating allergens and analysing the immune response responsible for the eczema. In total 15 candidate allergens have been isolated, expressed in E. coli and the proteins purified. Expression of chosen allergens in insect cells and barley is in progress. Our results on the immune response causing IBH indicate that there is an imbalance between Th1, Th2 and T regulatory cells. Therefore it should be possible to develop immunotherapy by Th1 focusing and induction of allergen specific T regulatory cells. The following approaches will be tried to develop a curative and/or preventive therapy

  • Vaccination/desensitization with purified recombinant allergens in a Th1 focusing adjuvant
  • Vaccination/desensitization with allergen genes on a viral vector.
  • Mucosal vaccination/desensitization feeding horses with barley expressing recombinant allergens.

In every case the specific humoral and cellular immune response following immunotherapy will be monitored and compared to controls. Vaccination experiment with recombinant allergens in Th1 adjuvant were started 2010.

The project is financed by the Agricultural Productivity Fund of Iceland, the Icelandic Research Fund (RANNIS) the Research Fund of the University of Iceland, The Swiss National Science Foundation, Þróunarfjárnefnd hrossaræktarinnar and Hrossræktarsamtök Suðurlands.

 

Publications from the Insect bite hypersenstivity project.  Published articles

 

M.Sc. Ph.D. and Dr. med. vet. projects in insect bite hypersensitivity