Tick Bites – more dangerous than we realise?

A tick climbing on vegetation

We vets are always going on about tick control – and to be honest, you’ve probably let it flow over you (don’t worry, we all do it!). However, the importance of avoiding or preventing tick bites has been front page news this week, with the revelation that former England rugby player Matt Dawson was seriously ill with an infection transmitted by a tick bite. It’s not just our pets that are at risk – livestock, us and our families are also potentially in danger – but by treating our pets, we can help break the tick life-cycle, and minimise the danger. It’s worth bearing in mind that about one dog in three is affected by ticks in any given season – and that even the inner cities aren’t safe (Matt Dawson was bitten and infected in a central-London park).

In this blog, we’re going to take a brief look at the tick life cycle, examine the different diseases carried by ticks in the UK, and then discuss ways of preventing, or at least minimising, disease spread.

 

Ticks aren’t actually insects – they are members of Class Arachnida, and as such are quite closely related to spiders. They are obligate parasites, in that they can ONLY survive on blood meals, sucked out of larger animals. Although there are several different species of tick in the UK, the most important are Ixodes ricinus (the “Sheep Tick”) – accounting for about 90% of the population – Dermacentor reticularis (the “Meadow Tick”) and the rare, newly arrived Rhipicephalus sanguineus (the “Kennel Tick”, so known because it can survive indoors, reinfesting people and pets inside the home).

However, the basic life-cycle of all ticks is essentially the same – the adults climb up onto vegetation (or, in the case of the Kennel Tick, walls and furniture) to sniff out their prey. When a large, warm-blooded animal walks past, they climb on board and suck blood. For the first 24-48 hours, they take their time, making sure they’re well attached and embedded in the skin, then they start a series of rapid-feeding cycles (interestingly, the females are by far the worst – male ticks are generally less greedy!). They then mate, and lay their eggs, which fall to the ground. The eggs hatch when the environment is right (generally warm and wet), and the juvenile forms climb up, feed, and then metamorphose – ultimately into adults to complete the cycle.

 

Although a tick bite is unpleasant, it isn’t usually dangerous in itself. However, ticks in the UK can carry three important diseases which put our pets (and potentially us) at risk.

 

The first is Lyme Disease, also known as Borreliosis. This is caused by a bacterium (Borrelia burgdorferi), and is in many ways the most dangerous of all the tick-borne diseases found in the UK. This is the infection that easily infects humans as well as dogs, and it can be really hard to diagnose and treat in both species. It is characterised by a relapsing, remitting fever (also known as an “undulating fever”), but also affects a wide range of different organs. In dogs, the typical symptoms are fever, intermittent (often shifting) lameness, loss of appetite, swollen lymph nodes and severe lethargy; there can also be a skin rash, kidney damage, heart problems, and fits or seizures. Unfortunately, the symptoms are so vague that diagnosing the condition is difficult – for us vets and our medical colleagues – so cases can be quite advanced before we can start treatment. Fortunately, the bacteria can be killed with certain antibiotics, although treatment for weeks or even months may be required to clear the bacteria.

 

The second disease, only recently established in the UK, is Babesiosis. This is caused by a parasite (Babesia canis) which lives inside red blood cells, causing them to break down. This leads to anaemia (visible as pale gums, shortness of breath, lethargy and sometimes jaundice), and may be fatal. Babesiosis is not spread by the Sheep Tick, only by the Meadow Tick and the Kennel Tick, which are fortunately rarer; however, it is now known to be established in the UK.

 

There are also another parasite that can spread through tick bites – Ehrlichiosis. Fortunately, this is rare as a cause of disease in the UK, first being diagnosed here in a non-travelled dog in 2013. This disease again usually causes severe anaemia.

 

So, how can we protect our pets (and, hopefully, ourselves)?

 

Well, the first is to repel ticks – there are a number of prescription tick spot-ons and collars which actively discourage ticks from biting a treated dog. Be careful though – some of these are toxic to cats.

 

However, they’re never 100% effective, so you also need a product to kill ticks, fast. During the attachment phase, the risk of the tick transmitting infection is very low. It’s when they sturt guzzling that they back-wash their saliva into the bloodstream, so if you can kill them before this, the risk is minimal. There are now a wide range of tick-killing medication that will kill the parasites in this timeframe – check with your vet for the best option for your dog.

 

For the same reason, removing ticks as soon as you find them is invaluable – in fact, you should always check your dog for ticks (and yourself, and your children!) after a walk. Always twist them out (we recommend the use of tick hooks!), so you don’t leave the head behind. NEVER try and burn them (it leaves the heads behind and risks burning the dog) or pull them out.

 

If you’re really worried about Lyme Disease in your dog, talk to your vet about the Lyme Disease vaccine – yes, dogs can be vaccinated against this infection! Sadly, there isn’t a human vaccine available yet.

 

Finally, if you’re travelling abroad, treat your pets against ticks before you return the UK! We only have a few tick-borne diseases in the UK – and until a few years ago, we only had one. The others have been carried into the UK by travelling dogs. Treatment used to be a legal requirement, but the rules have now been relaxed – you can join the campaign to get this reinstated here.

 

If you’re concerned about your dog’s health, contact your vet. If you think you may be infected, seek medical advice.

 

If you want to know more, check out…

The Big Tick Project results are here – we looked at this in a blog last year!

Good articles from the MSD Vet Manual on Lyme Disease here, Ehrlichiosis here, and other blood parasites (not all found in the UK!) here.

There’s a useful resource from the British Small Animal Veterinary Association on Babesiosis here.

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