Parasites and Your Pet


This fact sheet covers parasitic problems affecting dogs and cats. It excludes fleas, which are covered by our fact sheet Fleas & your pet.

  • Lice
    Trichdectes canis
    Linognathus setosus

Lice are tiny, slow-moving insects that can be seen with the naked eye. You may also be able to see their eggs, which stick to the hairs of their host. Lice can cause an animal to start itching and scratching, leading to irritation and restlessness. Since lice are species specific, they will not spread from animals to humans. In animals, lice are often associated with lack of condition and with either poor diet or poor environmental conditions.

Trichodectes canis and Linognathus setosus are the species of lice that affect dogs. Herbal repellent powders or lemon based rinses can prove useful in repelling lice. Garlic can also help, when used either internally or directly on the coat. Denes Liquid Garlic is suitable for external use. Regular harsh grooming will kill some lice and disrupt their breeding programme.

  • Ear Mites
    Otodectes cynotis

This parasite is transmitted easily between animals and affects cats, dogs, foxes and ferrets. It is possible to see the mite, which lives in the ear canal, causing inflammation and thick, brownish red crusts. Ear mites are common in cats and often spread from cats to dogs. The affected animal will shake its head and scratch and rub at its ears. Specific ear mite treatment (from your vet) will kill adult parasites, but the treatment will need repeating as younger mites mature. A few drops of olive oil or Denes Ear Cleaner, instilled into the ear canal and massaged in, will loosen material from deeper down the ear, helping to bring it to the top. Denes Respiratory Support (Garlic Oil) Capsules should be given daily and Denes Liquid Garlic, applied to moist cotton-wool swabs, can be used to clean the top of the ear canal.

  • Ticks
    Ixodes ricinus

Ticks are not permanent residents of their hosts. They attach themselves to feed and later fall away to lay eggs in the undergrowth. The young ticks hatch out and crawl to the ends of the branches, where they wait for a warm-blooded host to brush by. The tick is a grey or white coloured bean-shaped creature that can easily be recognised. Ticks vary in size, sometimes reaching a half inch when fully engorged with blood. If the tick is noticed before it is attached to the skin, it can be removed easily with a fine comb. If the tick is feeding from the host, touch it with neat essential oil of eucalyptus, alcohol or camphor oil on a fine brush, then wait a minute or two before plucking the tick away with tweezers or a tick remover. If it refuses to move, do not force it, as the head could break away in the skin and an infection develop (for which veterinary treatment would be needed). When the tick is removed, make sure it is killed.

If your pet frequents fields, woods or other areas where ticks are likely to be, groom the coat thoroughly after each walk, looking particularly for signs of this parasite.

  • Harvest Mites
    Trombicula autumnalis

This condition is seen late in summer and autumn, especially in chalky areas. Harvest mites attack the feet and ear flaps of dogs and cats as well as other species (including humans) causing irritation, licking and hair loss. It is possible to see harvest mites with the naked eye; they are easily recognised as bright orange dots. Anti-parasitic shampoo is an effective treatment for harvest mites.

  • Mange Mites
    Sarcoptes scabei

This condition is also known as fox mange and the parasite lives between the layers of the skin. It mostly affects dogs. Symptoms include skin irritation, loss of hair, self trauma and secondary bacterial infections of the skin. Microscopic examination is necessary for the diagnosis to be made, as the mites are far too small to be seen with the naked eye. This type of mange is very contagious, not only between animals, but it can also be passed to man. The normal route of transmission is by direct contact, although the mites can live away from the host for two or three days. In view of the human health risk involved, Sarcoptes infestations should be treated by the quickest and most effective methods. Parasitic washes, or injections, prescribed by your veterinary surgeon, should be used. It is often suggested that long-coated dogs are clipped, in order for any washes to reach the skin easily. In addition, Denes Mite Cream can be applied locally to help clear up affected areas.

Other natural remedies can be helpful in clearing up secondary infections, in toning the skin and in helping new coat growth. Give Denes Garlic Oil CapsulesGreenleaf and Complete Healthcare (All in One+) Powder as a supportive measure. Essential Oil Shampoo contains extracts of seaweed and birch. These herbs are known to improve skin disorders and encourage the growth of a healthy coat. Birch extract can also act as an effective insect repellent. Denes Homeopathic Sulphur 30c drops can also be used as a general remedy to help resolve skin problems caused by mites and fleas.

    Demodex canis

This condition is caused by a microscopic mite that lives in the hair follicles. Demodex is not infectious, lives its whole life-cycle in the skin and does not spread to humans. Most dogs have a few of these mites living in the skin without causing any problems. However, the body’s immune system is not always effective at controlling the mites. They can then increase in number, spread and cause severe inflammation, irritation and hair loss, with secondary bacterial infection of the skin. Demodectic mange mainly affects dogs but sometimes affects cats, quite often when the animal is in poor condition or suffering from stress. Demodex lives deeply in the skin and can be difficult to eliminate even after using special rinses or washes (prescribed by your vet). Local application of Denes Mite Creamcan also help.

A combination of natural and conventional medicine may be necessary to control this condition and to help prevent recurrence. Cleanse the coat with Essential Oil Shampoo, rinse and dry before applying Denes Skin Balm to affected areas. A natural, additive-free diet, supplemented with Denes Denes Garlic Oil CapsulesGreenleaf and Complete Healthcare (All in One+) Powder, should be given. A weekly fast day is particularly beneficial in these cases.

  • Cheyletiella
    Cheyletiella yasguri
    Cheyletiella blakei
    Cheyletiella parasitivorax

The cheyletiella mite causes a condition known as cheyletiella dermatitis, which results in severe flaking of the skin, often referred to as ‘walking dandruff’. Different species of the mite affect dogs, cats, rabbits and hares. However, infestations can spread from one species to another. It is possible for humans to become affected.

Diagnosis is made by examination of the skin material and treatment with antiparasitic shampoo is effective. Essential Oil Shampoo is useful here. Correct feeding and natural supplements are all part of the overall treatment.

  • Tapeworms
    Dipylidium caninum
    Taenia species
    Echinococcus granulosus

Both the dog and cat flea are intermediate hosts for some species of tapeworm. During grooming, an animal may inadvertently swallow a flea containing the cyst stage of the tapeworm life cycle. This will then develop into an adult tapeworm which will live in the dog or cat’s gut.

Tapeworms have a flat, segmented body and a small head, which is equipped with hooks and suckers for attachment to the gut wall. Each segment of the adult tapeworm contains both male and female reproductive organs that fill up with eggs. When the segments are mature, they break off and pass out of the body with the faeces. Tapeworm eggs must then pass through an intermediate host in order to complete the life-cycle. Most commonly, the dog and cat tapeworm is re-introduced into the gut of its new host by the flea. Because rodents (such as mice) also carry the tapeworm, cats who hunt are at greater risk from tapeworm infestation. Mature tapeworm segments often stick to the coat of long-haired animals. It is sometimes possible to see them around the animal’s tail. A dried tapeworm resembles a grain of rice, whilst a fresh one appears as a small flat white worm, which may move independently.

A dog or cat with a tapeworm problem may show symptoms of colic or chronic diarrhoea, loss of weight, poor general condition or irritation around the rectum.

  • Roundworms
    Toxocara canis
    Toxocara felis
    Toxocara leonina

The most common intestinal parasite in dogs and cats is the roundworm. Toxocara canis affects dogs, Toxocara felis affects cats and Toxocara leonina can affect both dogs and cats.

Young puppies and kittens can be seriously ill as a result of heavy roundworm infestations. Furthermore, the dog roundworm can pose a potentially serious health problem to humans. Young children can pick up roundworm eggs from play areas contaminated with dog faeces. These develop into larvae, which then migrate to various parts of the body including, the eye. This can seriously affect vision and has been known to cause blindness. This condition, known as visceral larvae migrans, is, fortunately, rare and can be prevented by regular worming and by ensuring that your dog does not foul areas where children are likely to play.

Adult roundworms are yellow-white in colour, have pointed ends and vary in size from about 4cm to 10cm. Normally living in the intestines, they produce vast numbers of eggs which pass out in the faeces. These eggs are resistant to both heat and cold and are capable of surviving in soil for many years. They are also sticky and can attach themselves to the coat and be ingested by a host during normal grooming. It is almost impossible for dogs and cats to avoid contact with roundworm.


Most puppies are infested with roundworm at birth. This happens because roundworm larvae migrate via the blood, settling in various parts of the body. During pregnancy, hormonal changes in the mother cause some of the larvae to mobilise and infest the unborn puppy. Larvae can also be passed from a bitch to her litter of puppies through her milk. A puppy infested with roundworms may appear to have a pot-belly, show signs of digestive upsets, slow growth and have a poor coat. The larvae can migrate to the lungs of puppies, causing a cough or, in severe cases, pneumonia. Sometimes whole worms are vomited or passed in the motions.

Both kittens and adult cats can be infested with roundworms by ingesting rodents, earthworms, birds and rabbits which contain the roundworm larvae, or by accidentally swallowing the eggs directly.


Susceptibility to parasitic infestations of any sort is influenced by general health. Recurrent problems are likely to be the result of poor overall condition, underlying illness (such as kidney or liver disease) or a weakened immune system. The situation can be improved by enhancing your pet’s overall lifestyle and strengthening the body’s own defences.

A more natural, additive free diet can help when combined with herbal remedies. Denes Garlic Oil Capsules can help deter parasites, including fleas, and provide support for the immune system. Denes Greenleaf Capsules can also help, acting as blood cleansers, clearing away poisons and toxins that can impair the functioning of the immune system.

Where worms are a problem, extra roughage in the diet (such as bran) can help by bulking up the food and encouraging the removal of worms from the bowel.

A small amount of grated raw carrot or turnip can also help in this respect, as can coconut (either ground or flaked) when added to the main meal. A weekly fast can also benefit general health by allowing the body to concentrate on correcting imbalances whilst the digestive system is resting.


There are proven procedures used to worm animals purely by natural means. However, these are rarely used now and full details would be too detailed to give in this leaflet.

Intestinal worms are very commonly seen in domestic pets and, because of the possible link with human disease, it is essential that animals are wormed regularly and thoroughly. Natural methods are extremely valuable for the prevention of such parasites. However, it is strongly recommended that adult dogs and cats are given an all round worming treatment (prescribed by the vet) usually four times yearly. If there are young children in the family, monthly worming is usually recommended. Worming routines for puppies and kittens should be discussed with your veterinary surgeon.

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