Ticks on dogs: removal and monitoring a bite

Overview

Ticks are arachnids rather than insects. Species found in parts of northern Europe include the castor bean tick, Ixodes ricinus, and taiga tick, Ixodes persulcatus. They look similar to the naked eye. They can occur in the same areas. They also share host animals.

Ticks can also occur in urban and suburban green spaces. A northern European study published in 2023 collected 342 ticks from dogs and cats at 10 veterinary practices. At least one tested pathogen was found in 17%. This describes the ticks examined, rather than the percentage of dogs becoming ill.

In the same northern European study, 84.5% were castor bean ticks. Taiga ticks accounted for 14.9%. These proportions cannot establish whether an individual tick carries disease. The study also found 1 brown dog tick.

Causes

A dog acquires ticks while moving through an area where they wait in vegetation for a suitable host. A tick may climb onto a grass leaf to await a passing animal, for example. It feeds on blood during only part of its life cycle.

The life cycle has 4 stages: egg, larva, nymph and adult. A castor bean tick larva feeds for about 2–3 days. A nymph's blood meal lasts about 4–6 days. An adult female may feed for 5–14 days. Do not wait this long before removal.

Most tick-borne pathogens pass in saliva while a tick feeds. Transmission time depends on both tick species and pathogen. Some Ehrlichia and Rickettsia bacteria, for example, can pass within just 3–6 hours. A minimum attachment time of 16–24 hours is described for Borrelia. Another estimate for Borrelia transmission is 24–48 hours. None of these times permits leaving a tick attached after finding it.

A tick larva hatching from an egg has 6 legs. A nymph already has 8. The castor bean tick changes hosts between blood meals. A female lays eggs in the environment and dies afterwards. Your dog is therefore only part of the tick's habitat.

Risk factors

Any dog going outdoors can acquire ticks. Hunting and free-roaming dogs have greater exposure. Long grass and borders between woodland and lawns are typical tick habitats. Local vegetation and host numbers affect tick abundance.

Weather and microclimate affect tick activity. Tick season can extend well into autumn where temperatures remain above freezing. Travel abroad may expose a dog to different tick species and diseases from those at home. In northern Europe, the brown dog tick can maintain its life cycle indoors.

Wild hosts include rodents, hares, deer and birds. Most tick species need conditions protecting them from drying out. Brown dog ticks can hide in building cracks and climb walls. An established indoor infestation therefore also requires environmental control.

Typical symptoms

The clearest finding is a parasite attached to the skin. An engorged female may be visible in the coat to the naked eye. The bite and any transmitted disease appear differently:

• An attached tick is seen or felt on the skin.
• A small, red, raised bump forms at the bite.
• Skin itches or becomes irritated around the attachment site.
• Your dog becomes tired or unusually subdued.
• Appetite decreases.
• Fever or lameness develops.

Infectious disease signs may appear only after the tick has detached. Not every infected dog develops signs. A small local bump differs from the expanding ring-shaped Lyme disease rash described in humans.

A recently attached tick is often flat. One feeding for several days becomes clearly rounder. A fully engorged female can be about 1 centimetre long. A small nymph may nevertheless go unnoticed in the coat.

Complications and consequences

Ticks can transmit diseases such as Lyme disease and anaplasmosis. Lyme disease may involve joint inflammation or kidney disease. Rarely, tick-borne encephalitis virus, or TBE virus, can cause severe central nervous system disease in dogs. However, many TBE infections cause no signs.

Heavy tick infestation can cause anaemia from blood loss. A bite wound can become infected. Mouthparts left in skin may cause a small abscess or foreign-body reaction. Toxins in some tick species' saliva can cause paralysis, seen in places such as the United States.

In severe cases, bacterial infection at the bite can become systemic. Anaplasma infection may reduce platelets. It can involve pinpoint bleeding beneath the skin or nosebleeds. These indicate disease rather than normal healing of bite bumps.

Babesiosis, which affects red blood cells, can also pass to a dog through a tick.

Diagnosis at the vet

An attached tick is identified by examining the dog. The vet also checks the local skin reaction. Small larvae and nymphs are harder to detect than engorged adult females. A laboratory can identify tick species when needed.

In a dog with general signs, previous exposure and the timeline are assessed. Travel history also affects investigation of possible infections. Suspected tick-borne disease prompts blood count and serum testing. Antibody tests can investigate infection.

Finding a tick does not itself demonstrate bacterial infection. Investigating anaplasmosis, for example, may combine antibody testing with PCR detecting bacterial genetic material. Tests are chosen according to the suspected disease.

Anaplasma antibodies may take 1–4 weeks to develop after exposure. Antibody testing may therefore be negative early in acute infection. A positive result may instead reflect previous infection. Testing is repeated after 3–4 weeks when needed to assess change.

A positive Anaplasma PCR generally confirms infection. However, a negative PCR does not exclude it. Unclear signs may also require investigation of other tick-borne infections. Several pathogens can occur together.

Liver enzymes may rise in Anaplasma infection. A blood smear may sometimes show clusters of Anaplasma bacteria in white blood cells. PCR can confirm such a finding.

Treatment

The vet prescribes any treatment and medicines needed. An individual, easily accessible tick can be removed at home with a suitable tool. With fine-tipped tweezers, grasp it as close to the skin as possible. Lift it away with a steady, gentle pull. Do not twist or jerk when using tweezers.

Do not squeeze the swollen rear body. Protective gloves reduce exposure to contents if it ruptures. Do not remove a tick by heating it or suffocating it with grease. Oil, alcohol and ether are not removal methods either.

After removal, clean the bite and your hands, for example with soap and water. If mouthparts remain and cannot easily be removed with clean tweezers, allow them to come out as skin heals. Do not dig deeply into skin. Dispose of the tick so it cannot reach another host.

A heavy infestation may require veterinary removal and hospital care. A confirmed bacterial tick-borne disease can be treated with antibiotics. Severe TBE is treated supportively, including correction of fluid balance where needed. Tick removal does not replace care for an infectious disease that has already begun.

Retained mouthparts can irritate skin, but the infection risk from a live attached tick is greater. Preventive medication may be needed after removal too, as checks may miss small ticks. An indoor brown dog tick infestation may require professional environmental treatment. Eradication can take several months.

Prevention

A daily whole-body check helps find attached ticks early. Important sites include the face, ears, armpits, spaces between toes, groin and around the anus. Reducing long grass and dense garden undergrowth decreases tick habitat. Avoiding known heavily infested areas also reduces exposure.

Choose protection according to your dog and local risk for the whole active season. Options include spot-on products, collars and oral medicines. Some repel ticks; others kill them after attachment. Seeing a tick in the coat therefore does not automatically mean protection has failed.

Duration of protection may also vary by tick species. Frequent swimming can shorten the effectiveness of some collars. Some canine pyrethroid products are poisonous to cats. Human TBE vaccination is not tick protection for dogs. There is no approved canine TBE vaccination programme. Protection relies on preventing tick exposure.

Tick products can cause skin irritation, vomiting or diarrhoea. A product for a pregnant or nursing dog is selected separately according to safety information. Broad insecticide treatment of large garden areas is not recommended because of environmental harm.

A tick collar may need sufficient skin contact to work. Shampooing can also reduce some topical products' effectiveness. Warm travel destinations may require year-round protection.

Important for dog owners

Record when a tick was found and removed, and where it was attached. Take a clear photograph of any skin change. Monitor the size, redness and swelling of the bite, and your dog's appetite, movement and alertness. Note travel destinations and current tick protection. Bring this information if investigation is needed.

Tell the vet about previous seizures before choosing protection. Isoxazolines have been associated with rare seizures. Mention cats and other animals in the home too. A dog can carry a tick home in the coat and onwards to human skin. Check yourself after walks as well.

Frequently asked questions

Should a tick be removed immediately?

Yes. Remove an attached tick as soon as possible after finding it. The attachment time needed for transmission depends on the pathogen. Do not wait for growth or natural detachment; use a suitable tool and monitor your dog. Do not use grease or heat.

What if the tick's head stays in the skin?

Usually, fragments of mouthparts remain. If they cannot easily be removed with clean tweezers, leave them for the skin to deal with during healing. Do not dig or try to cut them out. Increasing redness or swelling is a reason to contact a vet.

Does a bump at the bite mean Lyme disease?

No. A small raised bump can be a local hypersensitivity or foreign-body reaction. It differs from the ring-shaped Lyme rash recognised in humans. Monitor for general illness too, and have worsening skin examined. Fever or lameness may involve tick-borne disease.

Can a protected dog still have a tick?

Yes. Some oral medicines kill ticks only after attachment and do not repel them beforehand. Checks therefore remain part of care for a protected dog. Product suitability and instructions are checked individually. Other household animals also matter when choosing protection.

Can tick-borne disease pass from my dog to me?

Lyme disease, for example, does not spread directly from dog to human. However, a dog can bring home an infected tick. Dispose of removed ticks carefully and check both pets and people after walks. Do not squeeze a tick with bare fingers.