18 Oct 2010 - Equine Influenza Update
Equine flu can be a very serious and debilatating illness - sometimes even proving fatal in old, very young or infirm animals. It's highly contagious and a serious epidemic would effectively shut down the horse industry due to movement restriction, cancellation of events and closure of yards.
There are 2 main reasons for a flu outbreak:
- Disease in an un-vaccinated animal - as happened in a recent Cumbrian case. If diagnosis is prompt, the horse kept isolated and the yard restricted to prevent spread, this is usually fairly self-limiting. Other horses on the yard should be safe provided they are vaccinated against that particular strain of virus, but a booster will help give extra immunity.
- Disease outbreak in previously vaccinated animals. This can occur for two reasons:
- If the virus has mutated to a form not recognised by any existing vaccine. This effectively makes the entire horse population susceptible until a new vaccine can be developed.
- If an infected animal moves into an area where the vaccine being used is not effective against its particular strain. This happened in the 2007 equine influenza outbreak in Australia when an imported horse caused a massive epidemic. The outbreak was eventually controlled by strict movement restrictions and a new vaccine was adopted to protect against the strain involved.
Thankfully most flu outbreaks involve isolated cases and are a timely reminder of the importance of keeping vaccination up to date. Drug manufacturers constantly strive to include all the most recent strains of virus in their vaccines and vets endeavour to choose the most up to date and effective vaccines to provide the best cover for the horses under our care. We currently use Proteqflu (made by Merial Animal Health Ltd).