As the tick-borne virus encephalitis has been discovered in the blood of a patient in Yorkshire, it’s timely to find out what exactly is a tick and where do you find them?
What are ticks?
Ticks are a type of arachnid, so close cousins to spiders and mites, and like spiders they have eight legs and are oval-shaped. They come in hard-bodied versions, the Ixodidae family, and soft-bodied versions, the Argasidae.
Both families are blood-suckers and although each member of the family has its own range of preferred hosts, they will bite anything from birds to reptiles, wild and domestic animals to humans.
The Ixodidae ticks have a solid plate on their backs and beak-like mouthparts that extend forward of their bodies, which they use to attach themselves to a host painlessly. They then stay locked in place, unnoticed, until they have ingested their fill of blood, need to moult their old shell or are ready to lay eggs.
Argasidae ticks are more leathery and pillow-like and their mouthparts are on the underside of their bodies, so invisible from above.
How many different species of ticks are there in the UK?
In the UK there are around 20 types of endemic ticks, the most common coming from the Ixodidae family. Ixodes ricinus is found mainly on sheep and deer, Ixodes hexagonus love hedgehogs and Ixodes canisuga latches on to dogs and foxes. Having said that, most ticks will go for most warm-blooded animals that happen to pass by their patch because they don’t tend to move around a lot on their own.
Which tick carries encephalitis?
The tick-borne encephalitis is spread by Ixodes ricinus. These are relatively small ticks, the adult female slightly larger than the male. She can measure 3mm when she hasn’t fed but can enlarge to 11mm when engorged with blood. The male, on the other hand, starts at 2.4mm and the nymphs, or juvenile ticks, are even tinier – sometimes as small as a poppy seed.
In adult ricinus females the dark bony protection plate only covers about a third of the back, the rest of which is a reddish-brown. On the male the dark plate covers almost all of it, leaving only a red rim.
Where do Ixodes ricinus ticks live?
Ixodes ricinus ticks live on moorland, in deciduous woodland and on rough grasslands, especially where you find lots of rabbits and deer. They like things humid – the greatest risk to a tick is drying out. So they hide in the moist bases of long grass and tall plants and periodically climb up the stems to use them as points from which to ambush. When a host brushes past their location they launch themselves and hold on to its hair with the hooks on their legs.
These ticks don’t have eyes, but they do have sensory organs, small pits at the end of each of their two front legs that detect moisture, heat and carbon dioxide, all the hallmarks of a living, breathing animal.
Once the ticks have burrowed their mouthparts into their host they feed, their saliva producing anti-coagulants to ensure a good blood flow and anti-inflammatories to prevent their bite from becoming irritating, which might cause the host to scratch them off. If they are juvenile ticks, filling up with blood triggers a moult to the next stage in their lifecycle.
If they are adult, a good feed and mating with a nearby male leads to egg production and the female dropping off the host. Eggs hatch on the ground and the nymphs climb the vegetation to find their own hosts.
How to avoid being bitten by a tick
Although tick-borne encephalitis is very rare in the UK, ticks can also carry other diseases best avoided, probably the most well-known of which is Lyme Disease. The good news is that only about 1 in 5 ticks carries any infection, but you still don’t want to risk coming across that one.
Tick-borne encephalitis has so far been detected in North Yorkshire, Thetford Forest in Norfolk/Suffolk and the New Forest in Hampshire/Dorset.
So, if you are out walking in the countryside, particularly in those areas but also across much of the UK:
- Be aware when brushing past long grass and tall undergrowth, especially if it is a known deer area or a field with sheep, cows or rabbits.
- Wear light clothing so that you will see a tick if it lands on you and brush it off.
- It’s better not to have bare legs in the type of environment that ticks favour, and tucking your trouser legs into your socks can help.
- Treat exposed skin with insect repellent. Ticks dislike the smell of lavender, lemon, orange, peppermint, eucalyptus and cinnamon so if you smell like a sweet shop that could be a help.
- Check yourself all over for ticks when you get home. Ticks like warm, moist areas and hairy skin – sorry fellas! Adults usually get bitten on their legs but children should be checked above the waist particularly, including along their hair line and in their hair. Running a sticky roller over your clothes could pick up ticks that haven’t yet bitten.
What to do if you have been bitten by a tick
- Use tweezers to grasp the tick as close to your skin as you can and pull vertically. Or use a specialist tick remover that you can buy from a vets, a pet shop or the pet aisle in a supermarket.
- Wash the site of the bite and apply antiseptic.
- If you develop a rash, headaches, joint pain and/or a temperature, seek medical help straight away and say that you may have been bitten by a tick.