Parasite Control for Adult Dogs

Parasite Control for Adult Dogs.

Adult dogs have three main groups of parasites to control. Intestinal worms, fleas and heartworm. Regular treatment for these parasites helps keep your pet happy and healthy, as well as protecting people and other pets from potentially dangerous problems.

Intestinal Worms:

Worm tabletsIntestinal worms aren’t as dangerous to adult dogs as they are to puppies, but it is still important to regularly worm your adult dog. External signs of worms in dogs may include diarrhoea, weight loss, a pot-bellied appearance or scooting their bottom on the ground (this is more commonly caused by anal gland issues). Most dogs will not show any signs of mild to moderate worm burdens, so the owners may not realise they have a problem.

The two most important reasons (beside the dog’s own health) to worm your dog are to protect people and to protect livestock.

Hookworms can cause a problem called cutaneous larval migrans in people and gut problems. Hookworms complete their normal life cycle by being passed as in faeces, hatching and developing further, then lying in the environment until they have contact with an animal. They can then infect the new host by either penetrating through the skin or by ingestion. If they infect a dog, they follow certain chemical markers to migrate into the intestine. In people, the worm has trouble penetrating through the deep layers of the skin, so can end up crating burrows in the skin, which can be very itchy and unsightly. These are called cutaneous larval migrans. If they do penetrate through the skin, they can reach the intestine and set up a severe inflammatory response, which is very painful.

Tapeworm can cause problems with livestock. Some tapeworms have livestock as a host for part of their life cycle. When the tapeworm eggs are passed by dogs, the larvae that hatch can be picked up by grazing livestock. Once inside the grazing animal, they migrate and produce cysts in the abdomen or muscle. If these cysts are found at the abattoir, the entire animal carcass may be condemned, leading to considerable waste and money loss for farmers.

We recommend worming your dog every three months. Although intestinal worm treatments will only kill the worms in the animal at the time it is given (there is little or no residual activity), worming every three months means any developing worms will be killed before they can reproduce.


Many people still believe that fleas are a warm weather problem, so only need to be treated in spring and summer. The reality is that with modern heating and insulation in homes combined with more pets being kept indoors, fleas are now a year-round problem.

Because fleas are so good at reproducing (one female flea can produce over 5000 eggs), it is critical to keep on top of fleas at all times.

To check your dog for fleas, you can use a flea or nit comb. Focus on areas around the rump, belly and underneath the dog. You may find adult fleas, but more commonly you will find flea dirt (flea pooh). Flea pooh will look like a little curved bit of dirt, but if you put it onto a damp tissue and smear it you will see a red tinge left behind. This is because fleas are blood-suckers, so there is a lot of blood passed in their pooh.

Flea collars tend to be quite ineffective at controlling fleas as the front of the dog is protected by the collar, but the back end is generally too far away for the collar to have any effect.

Supermarket spot-on products are not necessarily the same as you get from the vet or good pet store. Many supermarket products are pyrethriod based. They are VERY toxic to cats (do not have these products in the house if you have a cat), and are also toxic to people and have been listed as likely or possible carcinogens. We do not recommend the use of these products.

We recommend an oral flea control product called Bravecto. This is given as a tasty chew once every three months, and is every effective with quick kill times. Because it is given orally, the dog can be washed and swim as much is you like without reducing its effectiveness. A quick kill time means fleas are killed before the have a chance to bite the dog or other pets multiple times.

Good quality spot-on products such as Activyl and Revolution are also safe and effective options, though it is worth discussing with your vet which may be appropriate for your pet. For example, some products may not be very water resistant so may not be recommended for dogs who love to swim.


It is recommended that all dogs in Australia have heartworm prevention.

Heartworm (Dirofilaria immitis) is a parasite that lives in the main blood vessel between the heart and the lungs. The adult worm produces infectious stages called microfilaria, which are discharged into the blood stream. These are then picked up by mosquitoes when they bite, develop a bit more in the mosquito then are injected into another dog when the mosquito bites. For heartworm to spread in a population of dogs you need two things – mosquitoes and infected dogs.

Fortunately in Bunbury we are in a lower risk area. We obviously have a LOT of mozzies, but few infected dogs (though those numbers can increase over summer when holiday makers from Perth bring their dogs with them). Perth, north of Perth and inland are much higher risk areas.

The main reason we recommend heartworm prevention for all dogs is the difficulty in treating the disease. The treatment takes several weeks, during which time the animal needs to be confined to a cage. The treatment also carries significant risks, as dying worms can break away and lodge in the lungs.

The first sign of heartworm disease is normally the dog coughing. This is caused by the worms creating blood clots which lodge in the lungs. The cough can be quite severe, and in some cases fatal. Infection is normally confirmed with a blood test.

We recommend using a long-acting injection to prevent heartworm. Although monthly products are as effective at preventing heartworm infections when given on time, being a week or so late giving a dose can create gaps in cover where an infection can be established. Studies have shown that the “average” pet owner only doses their pet 6-8 times per year, so the average dog is unprotected for nearly half the year. With the heartworm injection costing a similar amount to monthly oral chews, we feel it provides better protection and more convenience. We normally give the injection at the same time as the dog’s annual health check.

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