It was to educate and inform the horse industry that the Thoroughbred Breeders Association in partnership with The Horse Trust held a seminar on June 23rd at Tattersalls, Newmarket, which was attended by many of the representatives of horse associations and leading vets, breeders and trainers.

The beautiful sales ring formed an excellent lecture theatre for a day which was packed with information disseminated by some very distinguished speakers from around the world. Attendees were welcomed by Mr Joe Grimwade, Chairman of the TBA Veterinary Committee who introduced the morning speakers.

Dr Richard Newton, of the Animal Health Trust set the scene by giving the overview of the threat to the UK from these diseases and outlining the spread and transmission of these diseases through the world to date. He explained that these diseases are not contagious, that is they are not spread from horse to horse but require a vector to carry the virus from one infected horse to another, in the case of WNV this is the mosquito and in African Horse Sickness this is the culicoides midge. Illustrating his lecture with easy to understand pictures, charts and diagrams, the audience began to grasp the immense area over which these diseases have spread and are still travelling.

Professor Phillip Mellor from The Institute of Animal Health continued the discussion on West Nile Virus, and compared it to Bluetongue, the vector borne disease which reached flocks in the UK spread by strong winds from the continent wafting midges carrying the virus into East Anglia where they were able to infect the local sheep population. The control measure used for these outbreaks was slaughter. Blue tongue vaccination has now been made available to UK farmers and they are being encouraged to use it. 

Professor Alan Guthrie, (Director of the Equine Research Centre, University of Pretoria), then made a memorable address on African Horse Sickness, illustrating it with vivid and sometimes quite sickening pictures and videos of this most unpleasant disease; some members of the audience were visibly shocked at the cruel and savage nature of this infection.

Again, African Horse Sickness is not contagious, but is spread by the culicoides midge biting infected horses and then biting other uninfected animals to pass the virus on. Professor Gurthrie stressed that the disease required midges to live in temperatures of 12 degrees or higher and that until recently our climate would have precluded the occurrence of this virus and its vectors. However, with the advent of climate change this state of affairs would not last and midges would most probably arrive on wind borne incursions, as happened with the blue tongue virus. There is already fear that carrier animals could arrive here as imports for zoos, as happened some years ago in Spain in 1966, where midges carried the disease to the local population.

Dr Josie Traub-Dargatz Professor of Equine Medicine at Colorado State University spoke of the arrival of West Nile Virus into America and how, from a small original outbreak in New York State (traced to infected birds from Israel) it had spread throughout the US resulting in approximately 30,000 cases in one year. Measures to counteract the spread were an aggressive vaccination policy , together with larvicidal measures and vector resistent housing which together resulted in a steep fall in the number of cases, to around 450 annually, all of whom are unvaccinated horses.

A lively question and answer discussion followed before lunch.

In the afternoon session. chaired by Brigadier Paul Jepson of the Horse Trust, Professor Guthrie enlarged on his morning discussion with comparisons of West Nile Virus in Africa and America. 

Dr Chris Oura, of the Institute for Animal Health at Pirbright, England, gave a most interesting paper on reference laboratory activity and responses should AHS strike in the UK. He was followed by Dr Jules Minke, Global Vaccine Manager of Merial, France, who gave a very technical but nonetheless riveting exposition on the development of vaccines to combat AHS and WNV. He was fascinating in discussing the development of one of the most significant changes in the field of vaccination with the introduction of several recumbent vaccines based on the canarypox (ALVAC) vector platform. This has resulted from the cloning of the virus genome, producing a much safer vaccine. One of the key factors is that this vaccine enables testers to distinguish between vaccinated animals and those which have been naturally infected. This is an important step forward.

Finally Dr. Matthew Hartley of DEFRA spoke about prevention and control of AHS and WNV in the UK. Although his speech was listened to intently, the contents received a somewhat mixed reception as it became clear to the audience that DEFRA’s policy is in the position of being governed by the directives emanating from the EU, specifically Directive 1992/35 which controls the action of all member states in the case of an outbreak of an emerging equine disease. (This was introduced 16 years ago when developing a policy to enable the Barcelona Olympics to take place). This directive does not allow for vaccination, or the carrying out of a policy similar to that which has proved so successful in the US.

Dr Hartley explained that any representation from the UK directly to the EU to change this Directive would not be successful. Firstly, measures to contain equine diseases apparently are not high on the EU’s list of things to be done, and secondly any approach would need to be multi-national. A single national approach would fail. This aroused a certain amount of indignation amongst some of the delegates when it was realised that the measures taken in S. Africa to contain and control outbreaks of AHS would not be allowed in the UK, nor would the UK be permitted to implement a policy of vaccination for WNV in the event of an outbreak.

The Conference was summarised expertly by Ms Kirsten Rausing, Chairman of the TBA, who then asked for the delegates’ support in organising approaches to the EU, to change Directive 1992/35, through the European Breeders Association which would be multi-national. This support was readily forthcoming.

Brig. Jepson informed the assembly that the Horse Trust has brought together DEFRA, Institute for Animal Health, BHRA, BHS, Animal Health Trust, The Donkey Sanctuary, the insurance industry, BEVA, CU Veterinary School, and other key interest groups in a working party to develop a control strategy for AHS. The next step will be to draft proposals for a revised strategy for the EU, which it is hoped will supercede directive 1992/35. He asked all organisations in the horse world to support this working party. 

In conclusion, it was noted that the arrival of these two diseases in the UK would be dependent on climate change, and a warmer climate. However, the arrival of Bluetongue in sheep has been a wake up call and the method of transmission and infection is identical. Advice that Border Controls need to be tightened was readily accepted by the delegates. Awareness and dissemination of knowledge about these two diseases needs to be widespread, as only by being observant could the first early signs be detected. Everyone involved with equines must learn about these diseases and be on their guard. The overriding message of the Conference was that it is not IF they come, but WHEN.

Adrianne Smyth - June 2008