The most important management practice for the control of canine endoparasites is effective sanitation. Faeces should be removed from kennels and runs frequently. Dogs' exercise areas should possess hard, easy to clean surfaces. The use of disinfectants in the cleaning of runs is desirable. However, many parasite eggs are very resistant, and can be killed only by prolonged steam or flame thrower treatment of kennel areas.

Parasites usually develop best in warmth and moisture, so infection can be minimised by ensuring that all dog runs are constructed with good drainage, adequate ventilation, and, is possible, exposure to sunlight.

It is good management practice to have dogs examined periodically for parasite infections and treated with the appropriate anthelmintics. Good management practices with bitches are especially important to prevent transmission of Toxacara canis or transmammary transmission of threadworms or hookworms.

Canine infection with some parasites is dependent upon contact with another animal species that is serving as the intermediate host. Dogs should be prevented from eating the uncooked meat of intermediate hosts, such as rabbits that may transmit Taenia pisiformis, or sheep and cattle that may harbour other tapeworms. Since insect act as the intermediate host for Dirofilaria (Not prevalent in New Zealand), Dipylidium, and Dipetalonema, insect control is an important consideration in the prevention of those parasites. Slugs serve as the intermediate host of Filaroides osleri (Not prevalent in New Zealand).

Drugs used to control nematodes and cestodes are termed anthelmintics. Chemicals may eliminate parasites in a variety of ways, such as paralysing them and allowing the host to expel them, by halting their ability to metabolise nutrients, thus killing them, any by limiting their ability to reproduce. Different chemicals may act on one or more of these ways. Anthelmintics should have the following characteristics:

• Be effective when used under a variety of conditions. Parasites vary greatly in their susceptibility to different drugs.
• Have a wide therapeutic index or margin of safety. That is, the dose of the drug used should be toxic to the parasite without causing any damage to the host.
• Be easy to administer

Since the beginning of this century, many chemicals have been used to eliminate parasites from their hosts. The earliest compounds were relatively ineffective, but much progress has been made in recent decades. The discovery of phenothiazine in the late 1930's was the first major breakthrough in the development of anthelmintics. This drug has a wide margin of safety and, when introduced, provided limited control of several important livestock parasites. Piperazine was first employed as an anthelmintic in the 1950's. It is still widely used because it has a high therapeutic index and is effective against Toxacara and Toxascaris.

A revolutionary advance in the control of internal parasites came with the introduction of thiabendzole, the first of the benzimidazole class of compounds in the early 1960's. This product has been extremely successful in the control of a wide range of nematodes. It is effective against the adults and also kills eggs and larvae.

The tetrahydropyrimidines, which include the products morantel and pyrantel, were also introduced in the late 1960's. They have a wide range of spectrum of activity, killing Toxascaris, Toxacara, Ancylostoma and Uncinaria adults.

The organophosphorous compounds, such as dichlorvos, are widely effective against nematodes in the gastrointestinal tract. These compounds are cholinesterase inhibitors, and therefore are toxic to the parasites and may be toxic to the host. When used at the correct dose, these drugs will kill the parasites without damage to the host. However, if other organophosphorus compounds are being used to treat external parasites, the two used at the same time may be sufficient to harm dogs.

More recently developed drugs include oxantel and febantel.

Drugs used in the treatment of cestode infections macrocyclic lactones, bunamidine, dithhiazanine iodide, diethylcarbamazine. Praziquantel is the most commonly used cestocide nowadays.

Existing anthelmintics have a number of deficiencies are:

• Some anthelmintics cause undue stress and can be toxic
• Many anthelmintics have limited spectra of effectiveness so several different treatment regimens have to be given if dogs are infected by many parasites
• Few compounds, if any, are effective against larval forms migrating or dormant in body tissues