As arachnid superorders go, ticks are pretty evolutionarily successful. They’ve been around for at least 100 million years in one variety or another, with their main party trick – hanging around until they can latch a host to feed on – working on thousands of different animals across almost endless environments. But how concerned should you be about them in the UK? You won’t miss the blood they take, but they can cause a variety of unpleasant conditions in their hosts – and there’s some evidence that their population is growing. Just so we’re all on the same page, there are at least 900 species of ticks currently operating across every continent – some targeting seabirds and lizards, others cattle or dogs. Ticks sense vibrations and body heat, and will find a good place to wait for a host, then latch on to it, finding a patch of skin where the animal’s blood vessels run close to the surface and where it’s hard to be scratched away. At this point, it digs in and inserts its barbed, tubular mouthpart – sometimes secreting attachment “cement” to make itself harder to remove. In between slurps, it squirts saliva into the wound, containing a protein that prevents the host’s blood from clotting. It’s this saliva that causes a lot of tick-related issues, not only by transmitting pathogens, but by countering the host’s own bodily responses in ways that can be harmful. Shutting down pain receptors and the immune system is helpful for ticks, for example, but for hosts, it can lead to serious problems. “Lyme disease, probably the condition most strongly associated with ticks, is a bacterial infection, which might affect as many as 5,000 people each year in the UK,” says Dr Tim Brooks, head of the rare and imported pathogens laborator (RIPL). “The most common symptom is a spreading, bulls-eye rash at the site of the tick bite, which typically develops up to a month after being bitten, but other symptoms include a non-specific flu-like illness, a facial droop, nerve pains and numbness or tingling in the hands or feet.” More recently, ticks have also been found in the UK carrying tick-borne encephalitis, or TBE, which can cause a range of diseases, from a completely asymptomatic infection or mild flu-like illness, all the way to severe infection in the central nervous system such as meningitis or swelling of the brain. More information about symptoms can be found on the NHS website. TBE has been prevalent in many parts of the world, including several European countries, but was first detected in ticks in England in 2019. Cases in humans in the UK have been – so far – thankfully rare. In 2017, former England rugby captain Matt Dawson had to undergo heart surgery after a tick bite. So, is there more cause for concern now? It’s tough to say. “Since data collection began in 2005, there has been a general trend of increasing cases of laboratory-confirmed Lyme disease,” says Brooks. “That rise may be due to a combination of increased awareness as well as improved surveillance, and better access to diagnostics – but it may also be related to increased potential for encounters with ticks due to changes in wildlife populations and habitat modification that may have resulted in changes in tick distribution across the country.” At the same time, ticks don’t move around much by themselves, and this works in your favour if you’re trying to avoid them. “The most common UK tick species, the deer/sheep ticks, survive in many habitats, but prefer moist areas with dense ground level vegetation, which can be found in woodland, grassland, moorland, heathland and some urban parks and gardens,” says Brooks. “They don’t fly or jump. They wait on vegetation for a host to pass by, and then climb on – so while walking in green spaces, consider wearing clothing that covers your skin to make it more difficult for ticks to access a suitable place to bite, using insect repellent such as DEET and wearing light-coloured clothing so that you can easily spot ticks and brush them off.” It’s also not disastrous if one does manage to sink its fangs – well, mouthpart – into you. “On average, approximately 4% of ticks are infected with the bacteria that can cause Lyme disease in England and Wales,” says Brooks. “But the presence of the bacteria in a tick doesn’t automatically mean that the person will be infected, especially if the tick is removed promptly.” After spending time outside, it’s worth giving yourself and your pets – or children – a once-over for ticks: data from the UK Health Security Agency’s (UKHSA) Tick Surveillance Scheme shows that adults are commonly bitten on the legs, while children are commonly bitten around the head or neck. If you do find an unwanted passenger, removing it with a tick removal tool or fine-tipped tweezers can mitigate the risk of infection. And, if you start to experience symptoms, remember that rashes only occur in roughly two-thirds of cases of Lyme disease: contact your GP for antibiotics to fend it off. Try not to use ticks as an excuse to stay on the beaten track, however. Research suggests there are enormous benefits to getting out in nature, with forests, in particular helping to mitigate everything from anxiety to depression. Ticks might have made an evolutionary success of sitting around snacking for most of the time, but you don’t have to.