Ticks are related to spiders, mites and scorpions. There are many different species of tick living in Britain, each preferring to feed on the blood of different animal hosts. The one most likely to bite humans in Britain is the Sheep tick, Ixodes Ricinus. Despite its name, the sheep tick will feed from a wide variety of mammals and birds. Bites from other ticks are likely, including from the Hedgehog tick, Ixodes Hexagonus, and the Fox or Badger tick, Ixodes Canisuga.

There are different ticks in other parts of the world and they carry different diseases. If you take your dog overseas, be aware of this and take the necessary precautions. The Brown Dog Tick Rhipicephalus Sanguineus  has been brought into the UK from Europe on dogs and can survive and reproduce inside a home, unlike the native UK ticks. In the (US) the highest risk comes from the Deer tick, Ixodes Scapularis.

Life Cycle

There are four stages to a ticks life-cycle: egg, larva, nymph, and adult. Larvae, nymphs and adults spend most of the time on the ground protected by leaf litter, leaving this protection to find a meal. They feed only once in each stage, staying attached for a few days, then dropping to the ground to moult into the next stage or during winter. The whole life cycle from egg to adult lasts around two years.

To the naked eye the larvae look like minute pale spiders, not much bigger than a full stop. Nymphs are slightly larger, pinhead or poppy seed size. Larvae have six legs and nymphs and adults eight. It is the nymph which is most likely to bite you.

Note: Public Health England have produced a longer three minute video with some very good images of ticks.

Where they can be found

Ticks can be found in any place with moist air where they are protected from drying out, I. Ricinus is sensitive to climatic conditions, requiring a relative humidity of at least 80% to survive during its off-host periods, and is therefore restricted to areas of moderate to high rainfall with vegetation that retains a high humidity, such as litter layer and soil that remain humid during the day. Typical habitats vary across Europe, but typically include deciduous and coniferous woodland, heathland, moorland, rough pasture, forests and urban parks.” Ticks can also be found in private gardens, especially those with shady shrubberies or deep vegetation and a strong local wildlife population.

Numbers vary from place to place and from year to year, but ticks can be found across the UK. However, not all ticks carry disease, and infection rates in any one place may fluctuate from year to year.

Ticks feed on the blood of other animals. If a larval tick picks up an infection from a small animal such as a mice, when it next feeds as a nymph it can pass the infection to the next animal or human it bites.

They cannot jump or fly, but when ready for a meal they will climb a nearby piece of vegetation and wait for a passing animal or human to catch their hooked front legs. This behaviour is known as questing. The tick will not necessarily bite immediately, but will often spend some time finding a suitable site on the skin, so it is important to brush off pets and clothing before going inside.

When a tick has started to feed, its body will become filled with blood. Adult females can swell to many times their original size. As their blood sacs fill they generally become lighter in colour and can reach the size of a small pea, generally grey in colour. Larvae, nymphs and adult males do not swell as much as they feed, so the size of the tick is not a reliable guide to the risk of infection. If undisturbed, a tick will feed for around 5 to 7 days before letting go and dropping off.

The bite is usually painless and most people will only know they have been bitten if they happen to see a feeding tick attached to them. The risk of infection increases, the longer the tick is attached, but can happen at any time during feeding.  Given tick bites often go unnoticed, it may be difficult to determine how long it has been attached. That said, any tick bite should be considered as posing a risk of infection.

Note: Adults are most often bitten around the legs. While small children are generally bitten above the waist, so check their hairline and scalp.

The diseases Ticks carry

There are several diseases that can be caught from a tick bite in Britain. Four examples are:

  • Lyme Borreliosis, (bore-EL-ee-OH-sis) or Lyme disease, is by far the most common in the UK

  • Babesiosis (bab-EE-see-OH-sis)

  • Anaplasmosis (a-na-plas-MO-sis)

  • Rickettsiosis (ri-KET-see-OH-sis)

Note: Globally, the list of diseases carried by ticks is much longer. Some ticks carry more than one disease at the same time and can transfer them to you in a single bite. The resulting symptoms can be extremely confusing and liable to misdiagnosis. Treatment in such cases can be difficult. It is not known how often this happens in the UK.

Research

Ticks were found on almost one in three dogs during random checks of pets in the largest survey of its kind in the UK, with the South-West named among the areas of ‘highest risk’.

Researchers found that the tiny, spider-like creatures were present all across the country, with the likelihood of a dog picking one up equal in both rural and urban areas.They pose a risk as they can transmit bacteria that cause diseases such as Lyme disease, which can lead to very serious conditions including meningitis or heart failure if left untreated, even proving fatal.

The Tick-borne disease that can kill dogs will spread in UK, experts have warned.

Four dogs became seriously ill, from the babesiosis outbreak. One dog died and three become seriously ill after contracting babesiosis caused by a parasite carried by ticks. So far, the outbreak is confined to Harlow in Essex but the spread of the disease to the rest of the UK is thought to be inevitable.

Animal disease experts have also blamed a relaxation in European pet travel restrictions for the first recorded outbreak in the UK of a tick-borne disease.

Professor Richard Wall, of Bristol Universitys biological sciences school, who is leading the largest UK veterinary study of tick-borne disease, said the outbreak was of huge significanceand a major concern for animal health”. None of the dogs that contracted the disease had travelled out of the UK. But a relaxation in pet travel rules is considered the most likely reason behind the disease spreading to the UK.

It used to be compulsory for imported dogs to be treated for ticks before entering the UK and Ireland but the requirement was dropped in January 2012 to comply with EU regulations. Clive Swainsbury, the Harlow vet who first identified the disease in the UK, said increased pet travel had raised the risks of the disease spreading.

In a letter to the Veterinary Record alerting others in his profession to the outbreak, he and two colleagues wrote.There has been a marked increase in the number of dogs being rescued from abroad into the area, but we are at a loss to know why the requirement to treat dogs for ticks upon entry to the UK was relaxed.

Sean Wensley, president of the British Veterinary Association, said: The BVA lobbied hard against the relaxing of controls under the EU pet travel scheme, which included removing the requirement for tick treatment to prevent diseases such as babesiosis being introduced into the country, and it is disappointing to see our concerns potentially becoming a reality.

Government inspectors have examined a field where the dogs exercised. Nigel Gibbens, the chief vet, said,“there was no risk to human health, but he urged dog owners to check for ticks.

Swainsbury, a partner at Forest Veterinary Centre in Harlow, which treated three of the infected dogs, said the spread of the disease was inevitable. Furthermore speaking to BBC Radio 4s Today programme, he said: At the moment we have one well-defined localised area. The problem in the future is that every female tick will lay a couple of thousand eggs and all those offspring will carry the disease. Even if you do all that’s necessary, you are not going to stop the spread of the disease. He added: There are seriously ill dogs that we have encountered. The worst he had seen was a dog dying.”

The disease spreads in a way that is similar to how humans catch Malaria from mosquitoes, Swainsbury explained. He said;The parasite enters the bloodstream and in the process of trying to kill the parasite, the dog will destroy its own blood cells and become very anaemic. The only way to deal with it, is to kill the tick quickly, because the tick has to be feeding for 24 hours at least before it transmits the disease.

Bristol University’s Big Tickproject is examining thousands of animal ticks sent in by veterinary practices after a TV appeal by the broadcaster and naturalist Chris Packham.

The results are due in July, but Packham revealed that preliminary results suggested a widespread presence of tick-borne diseases such as Lyme disease and babesiosis. At the moment the indications are that the presence of these pathogens is widespread across the country,he told Today.

Harlow council urged dog owners to check their pets for ticks. It said: It is important that dog owners have their pets protected with anti-tick treatment and regularly check their dogs for ticks.It warned dog owners to avoid walking their pets in an area to the south of the town where the outbreak was first detected.

Be vigilant/No vaccine

There are no vaccines available in the UK for babesiosis. Treatment is focused on killing the parasite and stopping the dogs immune system from destroying more red blood cells.

Prevention

Prevention is based on routine use of anti-tick medication and removing ticks from dog fur. It is not thought to pose a risk to other pet species such as cats.

Packham said there is no doubtthe disease would spread. He added.An educational exercise is required to ensure that every dog owner knows that ticks are potentially a problem for them.” The key is vigilance to understand this problem and manage it.

Sources

  1. Medlock et al.Driving forces for changes in geographical

2. distribution of Ixodes Ricinus ticks in Europe. Parasites & Vectors 2013, 6:1

3. https://www.gov.uk/guidance/tick-surveillance-scheme

4. Bettridge et al. Distribution of Borrelia Burgdorferi, sensu lato in Ixodes ricinus Populations Across Central Britain. Vector borne and zoonotic diseases. 2013 Feb 19;13(X)

4. Robertson JN, Gray J, Stewart P. Tick bite and Lyme Borreliosis risk at a recreational site in England.Eur J Epidemiol. 2000;16(7):647–52.