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Equine Influenza ('Flu)



Equine influenza is an economically important contagious respiratory disease of horses resulting from infection with influenza A viruses of the H7N7 or H3N8 subtype. The disease is characterized by high fever, depression, coughing, and nasal discharge (Van Maanen and Cullinane 2002) and is often complicated by secondary bacterial infections sometimes leading to pneumonia and death (Newton and others 2000, Van Maanen et al., 2003). All major outbreaks in the past 20 years have been caused by the H3N8 subtype (Webster, 1993).

Nasal discharge

Weeping eye


The prevention and control of equine influenza depends heavily on vaccination and application of management regimes (Mumford, 1998). Historically, equine influenza vaccines contain inactivated whole virus and have been available since the early sixties (Bryans and others, 1966). Despite widespread use, there are periodic failures of vaccine efficacy, which continue to cause important losses to the horse industry (Newton and Mumford, 1995, Morley and others, 1999, Van Maanen and others, 2003).


In 2003 ProteqFluTM the first vector vaccine against equine influenza virus was licencesed in Europe. This new technology has the efficacy of a live vaccine with the safety of an inactivated vaccine. A vector is used to present immunogens of EIV to the animal’s immune system in such a way as to closely mimics natural infection, stimulating a rapid, strong immune response, leading to greater efficacy than conventional killed vaccines.


With respect to young foals, the dam passes on maternally derived antibodies (MDA) to protect young foals from disease during early life. MDA levels vary dramatically from foal to foal, and even low amounts of MDA interfere with active immunisation and vaccinating foals in the face of MDA may induce tolerance rather than immunity, potentially inhibiting immune responses to repeated subsequent vaccination for up to one year. However, vaccinating foals even from 4 months of age in the face of high MDA levels with Proteq-flu uniquely induce PRIMING of the immune system and not tolerance.


As a practice we have decided to use Proteq-Flu as our vaccine of choice offering you the best preventative healthcare for your horses that we can.




You may have heard about the Australian outbreak of equine influenza that struck 50,000 horses in 2007, but did you know that several areas of the UK also had outbreaks that year? From Wales to New South Wales, equine influenza poses a threat to horses right around the globe, because the virus can change and spread so rapidly.

Wherever they are, no horse should have to suffer the misery of equine influenza – a disease that can cause high temperature, nasal discharge and harsh dry cough.

Aussie flu




The short answer – yes. Equine influenza poses a threat to every horse in the UK. The good news is that you can protect your horse with an appropriate vaccination programme.

If you have already vaccinated against equine influenza, it’s very important for your horse to have further booster injections to maintain effectiveness.

If you don’t keep to the vaccination schedule recommended by your vet, protection is lost.

Equilis prequenza /prequenza Te - our current vaccine - provides the best protection against flu of those vaccines currently licensed in the UK