Other vets like me will have been invited to attend MSD’s online webinar on emerging infectious diseases in companion animals which took place online across the European region on Friday 16th April; there was a rough split with those of us in the North of Europe and Scandinavia attending a separate online session to colleagues in the South of Europe who face other challenges not yet with us in significant numbers, like leishmaniasis and heartworm.

For those of us in the now not-so-frozen North there was a familiar theme; we are, across Northern Europe, becoming warmer and wetter and parasites from sunnier climes are on their way to join us, along with the pathogens they harbour. Whilst the climate change theme was predictable, a common theme being seen in Europe and discussed by the presenters is that ticks may now be active year-round, and that could include winter.
There was some discussion about the discovery of evidence of the presence of Tick Borne Encephalitis (TBE) in the UK in 2019. Ian Wright from ESCCAP made the point that isn’t just about diseases that are new to us, like TBE, but the fact is that our prevalence data on lyme disease are now 20 years old…we can’t really be sure what is out there. Antibody titres to TBE were discovered in blood samples of culled deer which were tested because it is known that deer produce long lasting responses to the disease. The incidence figures quoted Norfolk, Suffolk, Hampshire and the Scottish Highlands as being the areas with the greatest numbers – so that would probably be the Thetford Forest, the New Forest and the Highlands – the places where we have seen plenty of deer, ticks and tick-borne diseases in the past because that’s where the habitat is. So we didn’t find TBE before because we hadn’t looked for it.

I attended the online Official Veterinary Conference last year and having watched the presentation of the overworked veterinary officer looking after Britain’s channel ports, I wasn’t convinced that our ability to stop companion animals coming through the channel ports in large numbers from continental Europe was particularly effective. At this online seminar I had the opportunity to put a couple of questions to Professor Richard Park, a parasitologist from Bristol. Tick borne encephalitis is thought to have entered the UK either in migrating birds or in pet animals and I asked him which he *thought* was most likely; he said we didn’t know and had no way of knowing. He did acknowledge that there had been a problem with animals being smuggled in via the channel ports.

Under the Pet Travel Scheme which we became familiar with when we were part of Europe pet owners are still obliged to have their animals vaccinated against rabies and treated against Echinococcus, but they are not obliged to treat against ticks. If you bring pets into GB you do need your pet passport; you may be obliged to sign a declaration that you won’t sell them but you can still bring them in. So that’s the pet travel scheme. But I recently came across this document dated March 2021 from DEFRA on the commercial import of dogs cats and ferrets.

What that document tells us is that “Trade movements from Northern Ireland to Great Britain are treated as national movements and as such, no animal health conditions are applicable. “
So, it appears to me that whatever the Pet Travel Scheme now lets Mr. and Mrs. pet owner do, all you have to do to get a large number of dogs into the UK is to drive a van load across the border from the Republic of Ireland and bob’s your uncle, they are in the UK. We have in the past had issues with imports of puppies from puppy farms in the Irish republic into UK. I cannot help but feel that with the present boom in dog sales this is an opportunity for somebody and with that opportunity will come other problems.
Whether you believe the dogs are going to come in via the channel ports or somewhere else the fact is that it is inevitable that arthropod vectors like ticks are going to come in. But having come in, the question then is, would there be a host population of animals able to sustain them?
Over the last couple of years I have been reading some of the “re-wilding” literature concerned with the attempt across Europe to restore habitats and increase biodiversity. There is an increasing body of evidence indicating that not just trees but also soils will be important in locking up carbon, that increasing the biodiversity of habitats improves soil health and therefore may help us to sequester carbon.

The book I finished most recently was The Missing Lynx by Ross Barnett which makes a reasonable case for the reintroduction of the European lynx to help us control deer populations. I asked Richard Park about whether he thought that introduction of the lynx would increase or decrease the risk from ticks. Richard said he was sceptical that the lynx would have much impact on deer populations but that one of the issues with rewilding is that if you have more habitat then you have more ticks. He also added that an argument has been put forward that if the deer aren’t there to bite then the ticks might be more likely to bite humans.

It was an interesting discussion but I doubt that we have any more idea of whether the hypothesis that absence of deer to feed on could result in more humans being bitten is more likely to be right than we have of whether TBE came to us with pet dogs or birds. I suspect that colleagues in the Republic of Ireland may feel the same unease about our newly found Tick Borne Encephalitis as we might have felt over the years about some of their puppy farms. But who knows, maybe TBE is in Ireland and they just haven’t found it yet. They have a growing deer population and issues with culling it, just as do and colleagues in the Republic of Ireland share other problems with us.

Climate change isn’t going away any time soon, there will be more pressure to combat it and along with that pressure, continued pressure to increase biodiversity, plant trees and improve soil health. Inevitably we will have more rough grazing and mixed woodland, and along with that we will have more ticks.

So keep an eye out! Thanks to MSD for an interesting seminar. And if you find any novel ticks and want to know what they are you can send them free to the government’s Tick Surveillance Scheme, details of which are at gov.uk.