REPORT of THOROUGHBRED BREEDERS
ASSOCIATION AND THE HORSE TRUST
JOINT CONFERENCE AT TATTERSALLS,
NEWMARKET
on EMERGING EQUINE
DISEASES
Many people may have heard something about the two
diseases which are expected to arrive in the UK within the next few years. These
are West Nile Virus and African Horse Sickness. Like most people I had vaguely
heard of these diseases but knew little of them, other than that they occurred
in faraway places and appeared to have little relevance to us in the UK.
Unfortunately it now seems that with the expected
climate change, as well as the huge increase in tropical and sub tropical
cargoes being flown into the UK, that we can all sadly expect to become familiar
with the prospect of these diseases arriving in the British Isles.
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
recombent 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 thehorse 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
Fields of Fire witness accounts of 2001