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Health - Parasites

Animals affected

Dogs, Cats






External parasites, such as fleas, ticks or phlebotomines, can get into the fur or the skin of dogs and cats. They act as vectors of certain diseases which can become serious, so their presence is a risk which should be avoided. It is also important to avoid them as they cause discomfort to the animals which we live with. Although they are mostly found in the natural environment, in areas with vegetation and in the hottest or most humid months, it is wise to take precautions all year round.

At the end of this section there is a brief guide to insects and parasites defined in detail so that you can find the information you need. However, we at FAADA recommend that you contact your local veterinary centre for everything related to the health of the animals you live with. Prevention is the best medicine.

In order to prevent infestations of fleas, lice, phlebotomines, mosquitos or ticks, one of the following treatments should be applied directly to the animal's skin: permethrin, fipronil, imidacloprid, deltamethrin or selamectin. They come as sprays, pipettes or collars and there are several brands. Generally the pipettes should be applied every 3 or 4 weeks, there are different types of collars which last between 1 and 6 months and the sprays are usually used on specific occasions when the animal is already affected.

Internal parasites, such as cestodes, coccidia and nematodes, live inside the body, generally in the intestines or even in the circulatory system, and cause general malaise, gastrointestinal problems, anaemia and even respiratory distress and nervousness.


Carrying out the prevention of external parasites helps to prevent the risk of being infected by parasites which are transmitted via these vectors. However, orofecal transmission is difficult to prevent in most cases as you cannot control what a dog or a cat ingests outside the home, including what we bring in on our shoes. This is why, it is recommendable to have treatment every three or four months, or after having spent time in higher risk areas (such as some time in the countryside), with the aim to eliminate any parasites they may have picked up. If there are none, the medicine will have no negative effects.


There are different brands with different active ingredients which eliminate these parasites to a greater or a lesser extent.

In general they are used as tablets but some also come in pipettes or even injection: fenbendazole, praziquantel, levamisole, milbemycin, ivermectin, metronidazole. Their use does not prevent the presence of parasites in the future, it acts only against those that are present at the moment of application.

At FAADA we recommend you do not administer medicine on your own, always consult a vet. It is also important to have regular check-ups, as often as the vet recommends.

Brief guide to insects and parasites

Fleas: They are 2mm long insects which feed on blood, they have the ability to jump to great heights. When they infest dogs and cats, they may cause irritation to the area, itching, unrest and even DAPP (allergy to the saliva of fleas). Furthermore, they may transmit Dipylidium caninum, an internal parasite which affects the digestive system.

Ticks: They are mites which stick to the skin in order to ingest blood. When they are adults, they may remain buried into the skin for a long time, increasing in size. They may cause weakness, loss of weight, anaemia and irritation in the affect area. They may also transmit diseases like babesiosis, anaplasmosis, ehrlichiosis or borreliosis (Lyme disease).

Phlebotomines: They are parasitic insects similar to small mosquitoes, 2-4 mm, that feed on blood. They can transmit leishmaniasis, a very serious disease which affects dogs.

Mosquitoes: The females of these arthropods feed on blood and their bite may cause malaise, irritation or hyper-sensibility. They may transmit the heartworm parasite.

Lice: These insects are 1-2mm long and feed on the skin or secretions by their hosts. They may provoke itching and alopecia and they can transmit Dipylidium caninum.

Biting flies: The stable fly can cause anaemia, pain and dermatitis. It is usually found in areas inhabited by cows or horses.

Coccidia: Isospora spp. Ingestion of oocysts, orofecal.

Giardias: Giardia duodenalis. Orofecal transmission, ingestion of cysts.

Cestodes (tapeworms): Taenia spp, Echinococcus spp, Dipylidium caninum, Mesocestoides spp. Lice or flea larvae are its vectors.

Ascarids: Toxocara spp. They are nematodes (roundworms). Direct ingestion of eggs, oro-fecal.

Dirofilaria: Dirofilaria spp. It is a nematode. Vector is the mosquito.


Our action

  • In Catalonia and others CCAA we carry out a yearly sterilisation and identification campaign aimed at the pets of private individuals at reasonable prices: Soy Responsable (I'm Responsible).
  • On our web page Soy Responsable, you will find up-to-date information about veterinary centres which offer good rates for families who can prove a lack of resources.
  • From FAADA we inform about the benefits of sterilization in companion animals and its consequences in case of not doing so.

What can you do?

  • Brush and check the animal’s fur regularly. If you have a dog, always do this after walking in the countryside or areas with vegetation. Be aware of possible behavioural changes and identify the area which may be causing itching or malaise.
  • Visit the vet so that they can advise you which product to use or when parasites have been detected on you dog or cat’s skin. If it is a tick, don’t try to pull it out as part of the insect could remain lodged in the animal’s body, which might cause an infection.
  • During the periods of highest risk, dogs should sleep indoors or in a closed space and some kind of mosquito deterrent should be used.
  • If you have detected the presence of any of these parasites, it is recommendable that you make sure you disinfect the whole house, including vacuuming the floor and any fabrics, such as rugs, sofas or beds. With medication the adult specimens of these parasites are eliminated from your dog or cat, but it is possible that young forms may remain in these areas.

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