Information on internal and external parasites in cats and dogs.

learn about cats & dogs with internal or external parasites

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  1. What are Parasites?
  2. What Causes Parasites?
  3. Diagnosing Parasites
  4. Help for Parasites
  5. More Information on Parasites

What are Parasites?

A parasite is an organism that gets its nourishment by feeding either on or within another animal and it is fairly common for our pets to become the unhappy hosts to a number of unwanted organisms. Parasites can be broken down into two main groups, the external parasites such as ticks, fleas, and ear mites, and the internal parasites such as worms which live inside the body and can affect a number of organs. Examples of internal parasites include heartworm, roundworm, and tapeworm.

External parasites, especially fleas are a worrisome problem for pet owners and their pets alike. Getting rid of fleas is no easy task, and sensitive pets may even develop an allergy to flea bites resulting in a condition called flea-bite dermatitis. Other parasites such as mange and ticks can be incredibly harmful to our beloved pets, but the good news is that most external parasites can be avoided to a certain extent with preventative treatments and thorough grooming.

Internal parasites are a common problem affecting almost all pets at some point in their lives. In fact most pets will have intestinal worms either before birth or within the first few months of life. It is therefore necessary to regularly treat animals against worms aiming at preventing parasitic infestation rather than trying to eradicate them once they are a problem. Common internal parasites include intestinal worms such as hookworms, roundworms, tapeworms, and whipworms; and worms that affect other areas of the body such as heartworm, bladder worm and eye worm.

What Causes Parasites?

External parasites are a part of the environment and they will jump at any opportunity to attach themselves to a comfy host such as your pet. Keeping your pets out of long grass and making sure their immediate environments are parasite free will go a long way in preventing parasites such as ticks and fleas. Internal parasites on the other hand have numerous ways of infecting your pet.

Many intestinal worms are contracted when your pet eats the infected larvae in the environment, such as eating infected food, or an infected mouse or flea. But they can also enter the body through the skin, the bottom of their feet and through direct contact with infected bodily fluids. Many kittens and puppies are infected in the uterus before birth or when they are suckling from their mothers.

Diagnosing Parasites

Your veterinarian will generally check for any signs of parasites when you take your pet in for a check-up. However, because there are so many different types of parasites the signs and symptoms vary greatly. External parasites are usually visible to the naked eye so when grooming your pet it is always a good idea to check for any signs of ticks or fleas.

Internal parasites are not as easy to spot, but in the case of intestinal parasites, worm segments or eggs can often be notices in your pet’s stool are on the fur surrounding the anus. Your vet will probably take a stool sample which will help to determine what type of parasite is present so that the appropriate treatment can be recommended.

Help for Parasites

There is no single treatment that will kill all parasites, but there are a number of different products that will help keep parasites in check and treat any infestations. Remember that prevention is the key and all pets should be on some form of preventative treatment to keep parasites away.

Conventional Treatments

There are a number of products such as Frontline Plus, Revolution, and Advantage that will help to keep your pet free from external parasites like ticks and fleas. Make sure you use only trusted products as harsh chemicals may be harmful to your pet. Conventional treatments for internal parasites vary depending on what parasite your pet has. There is no single "de-wormer" that can kill all worm-types and caution should always be taken when administering these medications to your pet.

Over-the counter de-wormers are generally less effective and more dangerous than veterinarian prescribed de-wormers, however even prescription de-wormers have the potential to cause unwanted side-effects and dangerous interactions with other medication. While treating and preventing internal parasites is important, make sure you know the facts and alternatives before giving our pet any new medication.

More Information on Parasites

Tips for managing Parasites
  • Make sure your pet is on some form of preventative program for both internal and external parasites. Preventing infestation is much more effective that treating one.
  • Washing your pets bedding regularly and make sure their immediate environment is parasite free. This may include regular vacuuming and washing of curtains and drapes (all the places where fleas and parasite larvae are likely to hide).
  • If possible, keep your pet clear from long grass and open fields where ticks are likely to be found. Also avoid letting your pet have contact with animals who may be infected or who are not of preventive programs.
  • Make sure your pets have a healthy sanitation area. Litter boxes should be cleaned regularly and stools should be removed from the garden at least once a week.


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