Up to 60% of horses in Australia suffer with insect-bite hypersensitivity, according to Kentucky Equine Research.

Yet we still lack a complete answer to this problem.

Horses with insect-bite hypersensitivity often present with signs including hair loss, thickening of the skin, weeping skin and ulceration of the skin, as a result of an over-reaction of the immune response. Infections may occur as a secondary result of the scratching and biting of those inflamed areas.

Research has been conducted to see if a special type of desensitisation vaccine, which reduces the immune response in these horses that have an over-reactive immune response, will assist, and has had favourable results.

“The vaccine was well tolerated, did not reveal any safety concerns, and did successfully induce the production of antibodies to block the action of IL-5,” commented Dr Laura Petroski, B.V.M.S, a veterinarian for Kentucky Equine Research.

IL-5, or interleukin 5 is the key regulator of eosinophils, which are inflammatory cells involved in the immune response.

While this vaccine needs further testing and registration, hope is afoot for our horses with chronic dermatitis as a result of insect bites.

In the meantime, look to utilise supplements with Vitamin E or Omega 3’s, which both have been clinically proven to reduce inflammation due to allergic reactions, including insect bites. Also consider applying insect repellent regularly during the high risk periods.

Information sourced from Kentucky Equine Research. Study reference Fettelschoss-Gabriel, A., V. Fettelschoss, F. Thoms, et al. Treating insect-bite hypersensitivity in horses with active vaccination against IL-5. The Journal of Allergy and Clinical Immunology. In press.