Holger Volk - Since winning the Kennel Club International Canine Health Award

 

Britain’s dog owners can consider themselves fortunate that their country is home to many extremely talented veterinary scientists - and lots of gifted practitioners of clinical medicine.

But there aren’t a huge number of vets who have made equally telling contributions in both advancing knowledge of the underlying science of canine diseases and in improving their day-to-day management.

Holger Volk, Professor of Veterinary Neurology and Neurosurgery at the Royal Veterinary College, London, is among that special group and in recognition of this, he was named a winner of the Kennel Club International Canine Health Award earlier this year.

Holger has made a considerable personal contribution to studying epilepsy, one of the most puzzling neurological diseases in dogs, and around him he has also built a research team with a formidable international reputation. The condition is identified in just under 1 per cent of the canine population, a similar level to that in humans. Canine epilepsy can have devastating effects on both the dog and its owner. One recent study in Europe found that a dog will have a much reduced life expectancy with epilepsy. It either dies as a direct result of the condition or is put to sleep because the owner can no longer cope with seeing their pet regularly suffering from uncontrollable seizures.

Understandably, vets have concentrated on developing and using therapies that reduce the frequency of these fits. But Holger argues that any treatment plan should consider the whole animal and not just focus on the most obvious clinical signs of the disease - the seizures. As yet, there are no medicines for epilepsy available without major side effects, and so decisions on how to deal with the patient must take account of the effects on the animal’s quality of life, and that of its owner, he says.

Holger came round to this way of thinking after talking to an owner who herself had suffered epileptic seizures from her early teens until the condition mysteriously resolved in her late 30s. “The thing is that I was having a seizure every now and again, but I was living with the effects of the treatment every single day,” she told him.

The consequences of taking anti-epileptic drugs appear to be the same in humans and dogs. There are a broad range of side effects, but owners are most upset by the sight of the dog appearing drunk and uncoordinated, and seeming to be excessively sleepy.

Vets can’t ask their patient how it is feeling in the same way doctors can ask humans, so they have to rely on the owner’s interpretation. Research by Holger’s group has shown that their perception of the dog’s quality of life is closely linked to their own – “If they are not feeling good themselves they tend to think that the dog is also suffering,” he explains.

As a result of Holger’s International Canine Health Award win, part of the Kennel Club’s annual £40,000 prize money, donated by the Vernon and Shirley Hill Foundation in the US, is being spent on a project intended to provide an objective assessment of the impact of drug side effects on the patient. Holger’s close colleague Rowena Packer is measuring precisely how the different anti-epileptic drugs change the way that the animal moves.

What the owners of epileptic dogs want most of all is information and the ability to do something positive about their pet’s condition. So in 2015, the RVC team launched a smartphone app that allows owners to record the pattern of seizures and send that valuable data back to the research team. The app has been so successful that it is being translated into a number of languages including French, German, Swedish, Spanish and Italian, for use by owners of epileptic dogs throughout Europe.

Crucially, the app also issues reminders to owners to give the dog its medication, usually needed twice a day. Holger’s research shows that poor compliance – owners missing scheduled treatments – is a serious issue in managing the disease. But he is sympathetic to the difficulties facing owners – “I was the owner of a dog with epilepsy, and it isn’t easy to give every dose. Sometimes you just forget,” he says.

The information sent to the RVC through the app is helping to create a better understanding of how the disease develops in different dogs, something that the owner’s vet is unlikely to be able to gather when they only see the patient intermittently.

Holger says that the latest evidence suggests that it is not the total number of seizures that determines whether the disease becomes more difficult to control, it is their timing – a cluster of several incidents over a short period of time is bad news for the patient. The investigations are also showing that the pattern of disease is very different in particular groups of patients. Approximately one third of epileptic dogs don’t respond to available treatments and are at risk of developing the most severe form of the disease, known as status epilepticus.

The RVC researchers have also begun working with Kennel Club-funded geneticists at the Animal Health Trust laboratory in Newmarket to look for a genetic basis for epilepsy. AHT researchers have already proven that a form of epilepsy found in an Italian dog breed, the Lagotto Romagnolo, is an inherited condition and identified the particular DNA mutation responsible.

However, Holger thinks that the search for a simple genetic cause for all the different types of epilepsy is likely to be long and fruitless. “I think we have a much better chance of finding genes that have a role in modifying the animal’s response to the disease rather than it being the actual cause.”

The team is looking for new approaches to the treatment of canine epilepsy but they are also trying to make sure that the existing treatments are used to greatest effect. Both may be necessary if we are to reduce the numbers of dogs that have to be euthanised because of uncontrolled seizures, he suggests.

Holger takes further inspiration from the woman mentioned earlier whose seizures stopped spontaneously after her two children were born. “The response that patients show to medication is a very individual thing. So we want owners and their vets to be more patient if the first or second treatment plans do not work. We may need to try different drugs and to take more care in seeing that we are giving them at the right dose,” he explains.

Epilepsy is one of those areas of veterinary medicine where there is much to be learned from the treatments developed in human hospitals – and the lessons can also go in the opposite direction. As a result, Holger has important research collaborations with NHS neurologists. “We are both looking for some sort of switch that will turn off seizures in our patients. We don’t know what that will be but we have a much better chance of finding it if we work together,” he says.

One of the most exciting new areas of research in canine epilepsy is on the effects of diet. “Breeders have often told me that they feel that the food that they give to their dogs does influence the control of their seizures. This shows why it is important to listen to others and not just follow your own ideas. In clinical veterinary medicine you cannot develop worthwhile new theories if you don’t talk to the people who are dealing with your patients every day.” 

Holger emphasises the importance of giving a consistent diet but it can be extremely difficult in a real world situation, because one of the effects of epilepsy drugs is to stimulate appetite and so these dogs will always be looking for food. This is then aggravated by the fact that the usual way for owners to show that they care for their pets is to feed them treats. Giving leftovers from human meals can also add to the problems because high salt levels in many human foods can interfere with the way that the dog processes the anti-epileptic drugs.

It isn’t just the amount of food that matters, the individual ingredients may also be important. The team published a study last year showing that a diet that is rich in molecules known as medium chain triglycerides provides much better control of seizures and completely eliminates them in a minority of cases.

Through the various projects mentioned above, Holger has driven forward the science of epilepsy in dogs further than any other researcher, but he is unwilling to take personal credit for the progress made since he arrived from the University of Hannover vet school in 2004.

“I was humbled and rather baffled to receive the Kennel Club award. I owe so much to the owners, breeders and scientific colleagues that I have worked with – the credit should echo back to them all. Together we are adding some more pieces to the jigsaw. When we can see the whole picture, we will be able to solve the riddle of epilepsy, and if I can have played a part in that process, that will make me very happy,” he says.

 

Nominations are currently being sought for the next awards which will be presented at a ceremony at the Kennel Club in London on 24th May 2017. With a prize fund totalling £65,000, the Kennel Club Charitable Trust is urging people to nominate themselves or their peers by 13th February 2017.  The awards will be judged by representatives from the veterinary profession and the world of scientific research, including experts in each of the nominees' selected fields. For more information about how to apply visit the Kennel Club’s website now.

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