Parasite control


External parasites

External parasites include fleas, ticks and mange mites and some are easier to eliminate than others.


Fleas are very common and in the dog most are actually the cat flea Ctenocephalides felis, which can live on either species. They only spend part of their life cycle living on the dog whilst they are gaining a blood meal; the rest of the cycle is spent in the environment so control on all the dogs and cats in the house and their surroundings are required. Some animals are allergic to flea saliva and for these continual flea control is important.

The flea can carry one type of tapeworm eggs – Dipylidium caninum – so controlling the fleas will reduce this problem.


Ticks are more seasonal as they spend part of their life cycle in rough long grass and part on an animal for a blood meal. Ticks can carry a number of diseases some life-threatening so if you are living or travelling outside the UK it is very important to use tick preventatives, as your dog will not have met these diseases and have no immunity.

Ixodes ricinus is the most common tick in Northern Europe and can carry Lyme Disease, a bacterial infection caused by Borrelia burgdorferi which mainly causes joint swelling and pain but can affect other organs, it is easily treated with antibiotics in the early stages so seek veterinary advice.

There are many other varieties of ticks in different parts of the world and the main diseases to worry about are Babesiosis, Ehrlichiosis and Hepatozoonosis. All of these can produce serious disease and dogs travelling outside the UK are immunologically naïve and should be protected with tick preventatives.

Ticks can be easily removed using a tick removing hook like these.

The hook is slipped under the tick and twisted until the tick releases hold on the dog. This means the mouthparts are removed in full. If a tick remover is not available a pair of forceps can be used but the tick is more difficult to remove entirely. If a lump forms or some bits are left veterinary advice should be obtained since the tick may cause a localised reaction and can carry diseases.


Mites come in many shapes and sizes some are more contagious from dog to dog than others.

Cheleytiella or the “walking dandruff” mite can make a dog very itchy (pruritic) and the skin is often flaky which combined with little white mites gives dandruff looking appearance. This may bite people too leaving little red spots on the skin.

Demodex canis is a mite more often found in the skin in young dogs. It needs prolonged contact to be transmitted and may be passed during suckling in the litter from the mother. Many dogs have a few Demodex mites in the hair follicles on their skin without showing any signs at all, but it is thought during periods of immune stress the Demodex multiply and cause hair loss and thickening of the skin.

Otodectes is the ear mite and is characterised but a dog scratching its ears and having a brown waxy discharge. The mites are contagious between dogs and also cat to a dog, so all members of the household may need treatment.

Sarcoptes scabei, commonly called scabies, causes intense pruritis particularly around the ear flaps and lower legs leading to self-trauma and secondary bacterial and Malassezia infection (leading to the dog smelling very “yeasty”). The mites are contagious and may be passed dog to dog or from foxes in the area.

Trombiculi or the harvest mite does not actually live on the dog for very long but causes intense itching, especially to the feet. They are red/orange in colour and can be seen with the naked eye.


Sandflies are not strictly a parasite, which lives on the dog, but mention is made because they transmit a serious disease called Leishmaniasis, which can be fatal if untreated and is widely prevalent in some of the warmer parts of Europe and South America. Cases are turning up in the UK and other areas where the disease was previously unknown as dogs travel more widely abroad and rescued dogs are brought in from countries where the condition is endemic.

Internal parasites


Roundworms are very common with Toxocara canis found most often. They may be passed in faeces or vomited up and resemble spaghetti. The lifecycle includes small larvae passing around the body and spending some time lodged in the body tissues. Most puppies have at least a few as the larvae may cross the placenta and infect the pup before birth. Worming by the breeder of the dam and puppies will minimise the infestation, but as worm eggs are in the environment it is essential to continue worming throughout the Beagle’s life. Good hygiene, especially with children, is very important as the eggs may hatch in humans leading to larval migration in the body. So-called aberrant larval migrants can lead to cysts forming such as in the eye and rarely causing blindness. Washing hands and disposing of faeces when fresh, as it takes time for the eggs to mature and be infective, will prevent this from occurring.


Tapeworms fall into two groups, those transmitted by fleas and those from rodents and small animals such as rabbits. An infected dog will often be seen to have small, white, rice grain-sized wriggly segments around the back end from those transmitted by fleas. In Europe, the fox may carry Echinococcus multilocularis, which can infect humans causing serious disease. Thus, under the PETS travel scheme dogs must be treated against this with praziquantel 24-72 hours before re-entry into the UK(check with DEFRA before travel).


Heartworms again fall into two groups. There is a worm called Angiostrongylus, which is an emerging parasite in the UK. Carried by slugs and snails, dogs can be infected by eating them or licking at the trails. There are very small slugs present in the UK, which can be found on grass when it is wet and this is likely to be the most common route of infection when dogs chew on grass. The worm can damage the lungs or, rarely, lodge in the heart as well as cause clotting disorders.

The second type of heartworm- called Dirofilaria immitus is not currently found in the UK or cooler parts of the world as mosquitoes transmit it and the species involved is only found in the warmer areas. This may infect dogs travelling abroad from outside the range it lives in and suitable preventatives should be given before travelling and for a month after return. In some parts of the world, this is a major problem and causes deaths in many dogs. It is important to use local knowledge and heed veterinary advice about control in these areas as the adult worms can lodge in the heart and cause fatalities as well as cause damage to other vital organs.