11 Parasites That Bug Pets: Your 2025 UK Guide

Parasites remain a significant concern for pet owners across the UK in 2025. Dogs and cats can harbour a variety of parasites that affect their health and well-being, some of which may pose zoonotic risks to humans. Understanding these parasites, their impact, and how to prevent and treat infestations is vital for responsible pet ownership.

This comprehensive guide brings you the latest UK information on common parasites affecting dogs and cats, current recommended treatments, preventive measures, and veterinary advice, drawing on the 2025 European Scientific Counsel Companion Animal Parasites (ESCCAP) guidelines for accuracy and reliability. UK spelling is used throughout, and the tone aims to be both warm and informative.

Fleas

Fleas are the most common external parasite affecting both dogs and cats in the UK. The cat flea (Ctenocephalides felis) is predominant on both species and can cause itching, allergic dermatitis, and irritation. Fleas are also vectors for tapeworms such as Dipylidium caninum.

Treatment: Modern spot-on treatments (e.g., fipronil, imidacloprid), oral medications (e.g., afoxolaner, fluralaner), and insect growth regulators are effective in killing fleas and breaking their life cycle.

Prevention: Regular year-round flea control, environmental cleaning, and treating all pets in the household are essential. Vacuuming carpets and washing pet bedding reduce flea eggs and larvae in the environment.

Ticks

Ticks (Ixodes ricinus and others) transmit diseases like Lyme disease and babesiosis. The UK’s milder climate has extended tick activity, increasing risk.

Treatment: Prompt removal of ticks reduces disease transmission risks. Veterinary-approved acaricidal spot-on or oral treatments offer effective tick control.

Prevention: Regular tick checks after outdoor walks, especially in wooded or grassy areas, and use of preventive products are recommended. Vaccination against Lyme disease is sometimes discussed but not commonly implemented in pets.

Roundworms (Toxocara spp.)

Roundworms, particularly Toxocara canis in dogs and Toxocara cati in cats, are intestinal parasites commonly found in young animals. They cause gastrointestinal upset and are zoonotic, potentially causing toxocariasis in humans.

Treatment: Routine deworming starting in puppies and kittens, frequently repeated during the first months of life, is essential. Adults should be dewormed at least four times a year or as per veterinary advice.

Prevention: Prevent pets from hunting or scavenging raw meat and practice good hygiene, including regular faeces removal. Regular worming treatments reduce pasture contamination.

Tapeworms

Puppies and adult pets can carry tapeworms like Dipylidium caninum and Taenia species, often acquired by ingesting fleas or rodents. Tapeworm segments resembling grains of rice are sometimes visible around the pet’s rear or in faeces.

Treatment: Praziquantel-based dewormers effectively clear tapeworm infections.

Prevention: Flea control and limiting hunting behaviour restrict tapeworm transmission. Worming protocols should include tapeworm coverage.

Whipworms

Whipworms (Trichuris vulpis) primarily affect dogs, residing in the large intestine and causing diarrhoea and weight loss.

Treatment: Anthelmintics such as fenbendazole or milbemycin oxime are used with veterinary guidance.

Prevention: Regular worming and good hygiene of enclosed outdoor areas reduce whipworm infection risk.

Hookworms

Hookworms (Ancylostoma species) are blood-feeding intestinal parasites that cause anaemia, diarrhoea, and skin irritation. They are more common in dogs and rarely found in cats.

Treatment: Anthelmintic treatments similar to those for roundworms are effective. Early diagnosis and treatment improve outcomes.

Prevention: Regular worming, avoiding contaminated environments, and good sanitation are key. Hookworms can occasionally infect humans, so hygiene precautions are important.

Sarcoptes (Scabies)

Dogs infested with Sarcoptes scabiei var. canis develop sarcoptic mange, a highly contagious skin disease characterised by intense itching, hair loss, and crusty red rashes.

Treatment: Veterinary-prescribed acaricidal treatments—topical or injectable—are necessary for curing sarcoptic mange.

Prevention: Isolate affected animals, wash bedding, and treat in-contact pets. Humans may experience transient itchy lesions but the mites do not establish long-term.

Lungworm

The lungworm Angiostrongylus vasorum is an emerging parasite in the UK, living in the heart and arteries of dogs and causing respiratory distress and abnormal bleeding.

Treatment: Antiparasitic drugs like fenbendazole or milbemycin oxime, administered under veterinary supervision, effectively treat lungworm.

Prevention: Prevent dogs from eating slugs or snails, which are intermediate hosts. Regular anthelmintic treatments are recommended in endemic areas.

Demodex

Demodex mites live in hair follicles and cause demodectic mange, often affecting puppies or immunocompromised dogs. The condition causes hair loss and skin rashes.

Treatment: Localised cases may resolve on their own, while severe infections require veterinary acaricidal therapy.

Prevention: Maintaining good overall pet health helps reduce risk as immune system dysfunction contributes to infestations.

Ear Mites

Ear mites (Otodectes cynotis) commonly affect dogs and cats, causing ear inflammation, irritation, head shaking, and scratching.

Treatment: Vet-prescribed topical acaricidal ear drops effectively clear infestations.

Prevention: Regular ear hygiene, inspections, and minimising contact with infested pets help prevent ear mite spread.

Heartworm (Travel Risk)

Though heartworm (Dirofilaria immitis) is not endemic to the UK, it poses a risk through pet travel or importation from southern Europe and other endemic areas.

Treatment: Heartworm treatment is complex and prolonged, so prevention is critical.

Prevention: Dogs travelling abroad should receive prophylactic heartworm medication before and after travel. Consult your vet for tailored advice.

Responsible Pet Ownership Advice

• Choose Reputable Breeders or Rehoming Centres: When looking for puppies or kittens, ensure you source from breeders who prioritise welfare or registered rehoming organisations. This reduces parasite risks and supports ethical pet acquisition.
• Regular Vet Visits: Annual or more frequent vet check-ups help identify and manage parasites early.
• Maintain Hygiene: Prompt faeces removal, regular washing of pet bedding, and managing outdoor areas reduce environmental parasite loads.
• Consistent Parasite Control: Follow your vet's advice for year-round flea, tick, worm, and mite control, adapting treatments to your pet’s lifestyle and region.
• Watch for Symptoms: Recognise signs such as itching, hair loss, coughing, diarrhoea, and seek veterinary advice promptly.

By following the latest veterinary guidance and evidence-based treatments and prevention outlined in the 2025 ESCCAP guidelines, UK pet owners can safeguard their dogs and cats from parasites and associated health issues. Responsible ownership includes well-informed sourcing, regular health assessments, and proactive environmental management to ensure your furry companions live happy, healthy lives.