Living With Dogs (14 page)

It’s only when you come into contact with affected animals that you realise how vicious parasites can be, and when vets advise people to worm their animals routinely, and maintain a good flea control programme, they aren’t simply looking to make another sale of flea rinses or worm tablets. As three of the parasites — puppy roundworm, sarcoptic mange and hydatid tapeworm — can also affect humans, it becomes doubly important for them to be controlled.

Dogs are highly dependent on their human owners, and never more so than in the ongoing battle with the pests which can make a misery of a dog’s life, and at worst, even threaten its life. Fleas, mites, ticks and lice cause irritation to the skin, while worms irritate the lining of the bowel, often leading to diarrhoea and, in extreme cases, vomiting. These conditions can be highly aggravating to a dog, and owners must be constantly vigilant to prevent and, if necessary, treat an infestation.

Ear mites are small, wingless insects which are so tiny that they can only be detected by using an auriscope with a magnifying eyepiece. They irritate the dog by chewing at the lining of the ear canal, and the body tries to compensate by producing excessive ear wax, which is usually the first sign of mites. Another is that a dog will scratch its ears with its hind legs, or even sit with its head cocked to one side.

Like fleas, ear mites are soil insects. They are frequently picked up in the first few weeks after birth, though the clinical symptoms may not appear until several weeks later. Treatment is by insecticidal ear drops, which quickly kill the adults, but it’s essential that you also kill the new mites, which hatch from eggs laid in the hairs around the entrance to the ear. Use insecticidal ‘spot-on’ drops. Check any other cats and dogs in the house because ear mites are highly contagious. I would recommend using spot-on drops on all animals in the household where ear mites have been diagnosed.

The first thing to be understood about fleas is that they are a soil insect which reproduces in dry dirt containing plenty of humus. They jump onto a dog when it lies down in dirt, and once they are carried in the dog’s coat, they will transfer onto carpet or bedding. They will also jump from dog to dog, and from cat to dog. They do not live on dogs, and the only reason they bother attaching themselves to dogs is to reproduce. They need to suck fresh dog’s blood, which contains substances that trigger the laying of an average of 1500 eggs per flea.

Fleas enjoy warmth and dryness, so they are less of a problem outdoors in winter, particularly in the southern states, but the growing problem we face is that central heating in our houses creates the perfect climate for the hatching of flea eggs throughout the year. Certainly, vets are now tending to see flea-allergic dermatitis all year round, whereas the traditional season used to be from October till the end of autumn.

Treatment involves killing the fleas on the dog, as well as the fleas in their environment; be they in bedding, in the carpet or, in a dry dirt patch, for example, under the house. It is no good killing the fleas if the animal is immediately re-infested when it returns to its basket or its favourite place in the back yard. Fleas can be killed by using specific spot-on insecticidal drops. Dogs can be prevented from lying in the dirt by fencing off the most troublesome areas. Dogs’ bedding should be washed weekly at the height of the flea season, and that should include an insecticide rinse.

Insecticides and growth retardants in aerosol cans may be used to kill fleas and eggs in domestic carpets. Each 125g container does about two standard-sized rooms, so four cans are usually needed for the average suburban house. Each treatment lasts from three to six months.

There is a range of products which are effective in killing fleas. The decision whether to choose a powder, a rinse or an internal insecticide largely depends on how effectively and consistently you have to apply the product. Many dogs are hard to handle when applying external insecticides because they object to the odour.

By far the best treatment is to use spot-on products which come in the form of a liquid that is applied every four weeks to the skin at the base of the dog’s neck, between the shoulder blades. The insecticide is absorbed into the skin fat, and when the flea bites into the skin it absorbs the insecticide and dies.

Flea powders last for three days, and most flea rinses work for five days, although they are immediately rendered useless if the dog goes swimming in a creek or runs under the garden sprinkler, and the insecticide is washed off the coat.

Another form of flea treatment is to use growth inhibitor tablets, which prevent flea eggs from becoming fertile. The fleas still bite the dog, but they don’t lay fertile eggs and over time there are less adult fleas to irritate dogs. The tablets need to be taken for at least six months before they begin to decrease the actual flea eggs in a dog’s environment. Dogs who go on these tablets can expect a much easier time in summer, when fleas are at their worst.

With all these products, you must use and re-use them, according to the directions, and not when the mood suits you.

It has been estimated that in human medicine only 70 per cent of patients comply with treatment regimes set by their doctors. The compliance rate would be much less in veterinary medicine, where you have the additional problems of dogs refusing to swallow a tablet or to be bathed. Vets have an ironic saying, ‘When all else fails, read the directions’, and that pretty well sums up the attitude of some clients. It’s instructive to recall that most dogs poisoned by snail bait are poisoned in their own homes, even though the directions on the snail bait packet clearly spell out the dangers. Many people simply don’t read or absorb the instructions, and are highly critical when their dog doesn’t get better. Many dog owners are looking for a magic button to get rid of a problem, and that doesn’t exist.

Lice are the least common of the pests, and I have only seen two cases of infested dogs in 45 years. They are larger than fleas and live their entire life cycle on the dog, scuttling along the surface of the skin, and laying their eggs at the base of the hairs. Affected dogs are unkempt, usually haven’t been groomed or washed for years, and look thoroughly unhygienic. The treatment is insecticidal spot-on drops which must be repeated regularly until all signs of lice eggs laid at the base of the coat hairs disappears.

The description ‘mangey’ stems from the mange caused by the sarcoptes mite, which is caught by dogs that have been in contact with mange-infected wildlife, like fox or wombat carcases. The condition is frequently seen in dogs that live in the outer suburbs, or go to the bush for weekends. It can also be contracted by humans, usually where their skin has brushed against the affected part of the dog’s coat, and often results in a rash on the forearm or in the webs of the fingers.

The most commonly affected areas of a dog are around the head, and the edges of the ear flaps, which become thickened and scaly. A dog suffering from mange will be far more irritated than it would be with a heavy flea infestation, and usually it can’t stop scratching. Treatment consists of several internal injections of an insecticide by a vet, together with an insecticidal bath which will produce a dramatic lowering of the irritation and the scratching. Continue the treatment until the coat hair is growing again.

The demodex mange mite does not possess a tough cuticle coat, so to survive it burrows into the hair follicles of the dog’s skin, breaking the hair off, and making it appear as though the dog is going bald. Every puppy acquires demodectic mites from its mother, but most never exhibit clinical symptoms because of the defence provided by the immune system. It’s only if the puppy has a poor immune system that it will contract the condition. Bull Terriers and the German breeds, like the German Shepherd and Dachshund, are more susceptible to the disease.

Small, bare patches appear on the head or the feet, and after some time these patches develop pustules which result in the skin becoming very irritated, causing the dog to scratch or chew the areas. The demodectic mange then spreads slowly to other parts of the body. It is not transmissible to humans. Treatment is difficult, because it is hard to get the required insecticide to penetrate the hair follicle, where the mite is living. A special rinse has been developed, but a more effective treatment is to have your vet give the affected dog a series of injections of internal insecticide.

Ticks are wingless, blood-sucking insects which are most common in the warmer areas of Australia. They can occur as far south as Lakes Entrance in Victoria, but it is unusual to find them in southern Victoria or Tasmania, unless an owner has recently returned from a trip to northern Australia with the dog. Like fleas, they are most common in the warm spring and summer months.

The adult tick lives in the soil, and dogs pick up tick larvae when they brush through grass. The larvae, or tick nymphs as they are called, attach themselves to dogs, and start sucking their blood, which enables them to transform into an adult tick. These ticks usually attach themselves to the skin folds, particularly in the head and neck area, and are also often found around the ears, lips and eyelids. They become bloated to the size of a large pea after sucking blood for five to seven days. The difference between fleas and ticks is that the tick buries its biting parts into the skin to suck blood, and so it’s immobile, whereas the flea jumps around.

One species of tick,
Ixodes holocyclus,
can cause paralysis and even death in a dog. To help them suck blood, all ticks pump anti-coagulant saliva into the dog’s skin, but the saliva of
Ixodes holocyclus
is toxic to the dog’s nervous system. The risk of serious illness to the dog makes it terribly important for an owner to kill any tick nymphs that get onto their dog by using an acaricidal insecticidal rinse or use a specific spot-on treatment.

Ticks have a tough cuticle coat, and a strong insecticide is needed to kill them. In tick areas, or before entering these areas, you should apply the specific spot-on insecticidal drops fortnightly during the tick season from September to March as a prophylactic. Continue treatment for a month after leaving tick areas. You should also examine the dog daily around the head and neck to look for any adult ticks which may have survived the insecticide. If you discover an adult tick, crush the head by using a pair of eyebrow tweezers.

Fleas are visible and the distress they cause to dogs is obvious. But far more sinister is the threat posed to dogs by worms. In the case of bowel worms, they rob the dog of nourishment, and create serious inflammatory reactions in the dog’s bowel, while heartworm poses a danger to the dog’s life by destroying the valves and lining of the heart. Fleas get more attention, but the internal parasites that are unseen can more commonly lead to death.

Even today, after so many years in practice, I’m continually amazed when I receive the results of clinical pathology tests performed on sick dogs, and discover that the primary reason for the illness is a heavy worm burden in the bowel. It happens because the owners don’t practise preventative medicine by worming their dogs, and it’s only when the worms become established in the bowel that they notice signs that the dog is not well. Just as you vaccinate your dog annually, so should you regularly give it tablets to prevent worms.

Dogs can be infested by four different bowel worms: roundworm, hookworm, whipworm and tapeworm. The life cycle of all except the tapeworm involves the production of eggs by adult worms in the bowel, which are passed by the dog in its droppings, and these in turn re-infect the dog, or other dogs, when they pick the eggs up off the ground and swallow them.

Roundworms look like a creamy-brown garden worm, and normally live in the first part of the bowel after the stomach. They lie together, partially blocking the bowel, and this causes bowel irritation and in heavy infestations, vomiting and diarrhoea.

Roundworm treatment is essential for all puppies because they are infected by their mothers before birth. It is important that pregnant bitches are wormed, because puppies can be born with quite a heavy infestation of roundworm. In serious cases puppies will sometimes vomit up roundworm. The first dose should be given between two and a half and three weeks of age, and repeated fortnightly until three months. From three to 12 months the dog should be treated monthly, and from then on, every three months for the rest of the dog’s life. Roundworm eggs can cause serious illness if swallowed by humans. The eggs cause the release in the bowel of larvae, which penetrate the bowel wall, and enter the bloodstream, resulting in very serious reactions in the human liver, brain, or eye.

Hookworm is a blood-sucking parasite which occurs in the small bowel and rapidly causes anaemia and weight loss. It thrives in mud and very wet conditions, and the larvae can penetrate the skin of a dog’s feet. Hookworm can be treated with special tablets, but nowadays most broad spectrum worming tablets will treat roundworm, hookworm and whipworm in the one dose.

Whipworm lives in the caecum (the junction between the small and large bowel), and as its name suggests, it looks like a long, single-threaded whip. It causes great irritation in the lower bowel, resulting in uncontrollable diarrhoea, haemorrhaging from the bowel and loss of bodyweight. Whipworm eggs can live in the soil for up to 10 years after they’ve been passed by a dog, so once an area has been contaminated, it’s very difficult to eliminate the source. Fire is very effective, but incinerating your property is an expensive way of getting rid of whipworm.

Tapeworm and the hydatid tapeworm both differ from the other three worms because they go through a secondary life cycle. In the case of the common tapeworm, this secondary life cycle is in the dog flea, while in the hydatid tapeworm, it is in sheep. Dogs become infested with tapeworm when they eat an infected flea, and they become infested with the hydatid tapeworm when they eat infected offal from sheep, which is either deliberately in their diet or from sheep carcases.