The major external parasites of dogs include fleas, ticks, mites and lice. Besides irritating the skin, these pests can transmit disease, suck blood and lead to serious skin infections. Fleas may harbor tapeworm larvae and cause Flea Allergic Dermatitis. Ticks can transmit Ehrlichiosis, Rocky Mountain Spotted Fever or Lyme Disease. Sarcoptes mites cause severe skin irritation on both dogs and their owners. None of these pests does much to improve the lives of our canine friends.

Fleas are parasites of most mammals and birds, particularly irritating because of their frequent bites. The usual flea to infest dogs is the cat flea, Ctenocephaldes felis, with the dog flea, Ctenocephaldes canis being less common. They will quickly and easily jump from dog to man to cat or so forth, not being particular from whence they feed. They prefer to live below 5000 feet elevation and thrive in warm, moist climates.

Fleas live by sucking blood from their hosts. Eggs are laid on the host or in carpet, bedding materials and the yard, hatching into maggot-like larvae, that feed on flea dirt, which is the fecal material of adult fleas made up primarily of blood and other debris in the area. The female flea can lay hundreds of eggs in her lifetime, which is why fleas seem to multiply before your eyes! The flea larvae form a cocoon, pupate and then hatch into adults. This whole cycle takes as little as 3 weeks, but can last upto 2 years; it will proceed fastest in the warm summer months.

The bite of the flea alone is quite itchy but in some dogs a severe, intense allergic reaction to flea saliva, known as Flea Allergic Dermatitis will also arise. These dogs have hair loss, extreme itching and secondary infections of the skin. Fleas may be identified by seeing 1-2mm black/brown specks racing (they move very fast) across the back, groin and hindleg areas of the dog. Tiny sand-sized black specks may be present in the fur. This is called flea dirt, which if wetted, will turn red, as it is basically digested blood. Tiny white specks may also be seen on the fur, these being the flea eggs. ((Fleas))

Ticks are blood-sucking parasites closely related to spiders and scorpions. There are several species of ticks including Rhipicephalus sanguineus the Brown Dog Tick, Dermacentor viriabilis the American Dog Tick and Ixodes species, the Deer Tick. All can transmit diseases such as Ehrlichiosis, Rocky Mountain Spotted Fever, Babesiosis and Lyme Disease and can cause a paralytic disease called Tick Paralysis. ((Ticks))

Ticks prefer to attach on the head and neck, in the ears, around the anus, near the shoulder blades and between the toes. A male and a female tick will usually attach together with the female becoming quite large as she engorges with blood. The female will detach and lay thousands of eggs in the environment. These eggs hatch into larval ticks called "seed ticks" which sometimes are seen in the thousands on some dogs. Seed ticks must feed on blood from a dog or other mammal and then they fall to the ground and molt into a "nymph" stage. Again, the nymphs must find a mammalian host, feed on blood and then fall to the ground and molt into adults.

As the adults find a host to feed on, the cycle is completed and begins again. This whole cycle can take from 2 months up to 2 years and will tend to proceed faster in warm, moist weather. Because all life stages can feed on your dog and because ticks lay large quantities of eggs, tick problems can escalate rapidly. Frequent and consistent treatment will be essential to ending and controlling the problem.

There is no one-plan-fits-all strategy, but in short, killing and repelling ticks on the dog, and destroying and removing the eggs and nymphs from the house and yard are essential parts of any strategy.

It is best to work with your veterinarian to select safe and effective products. There are hundreds if not thousands of products sold today, many that are unproven and unsafe. Your veterinarian will generally have the latest improvements and safest agents available. Avoid untrained pet store personnel who have little training in chemistry and parasite control. Most are simply trying to sell you a product, not treat your pet in the best possible manner.

TOPICAL REPELLANTS such as Frontline^tm and Advantage^tm, are applied to the skin of the dog or cat where they spread out and over the entire skin area. These provide a sort of total body flea collar and are very effective in killing and repelling fleas. These agents have minimal toxicity for most pets: side effects are very rare. This is considered the "state of the art" in flea and tick control today. Avoid "knock off" products. We have seen poor performance and some severe toxic reactions from many off-brand chemicals sold in pet and retail stores.

DIPS provide quick and effective tick kill and can usually be mixed from a concentrate and poured or sponged onto your dog. You must dip about every two weeks as the dip will weaken in about that time. Do not rinse off the dip to provide residual anti-tick activity. We have had great success with Paramite Dip.

TOPICAL SPRAYS work well to quickly kill ticks, and a few will provide residual protection or prevent eggs from hatching out later. Sprays can be used between dipping, and in conjunction with topical and systemic medications. Alcohol-based sprays work best, but some people and dogs may be bothered by the fumes, so less effective water-based treatments are also available. Please ask about products currently available.

SHAMPOOS also kill adult ticks, and assist in cleaning eggs and dirt from the coat, but have minimal residual activity or effectiveness against tick eggs. Using shampoo then dipping or using a spray is the best strategy.

TICK COLLARS, if they are high quality, can help kill and repel ticks, but should be viewed as part of a tick control program and not as an end to the problem. Poor quality collars can be toxic to your dog, and can irritate the skin on the neck of your pet, so avoid the grocery store brands. Some new collars like Preventic^tm release their chemical ingredient onto the skin and not only kill and repel ticks, but prevent the transmission of tick-borne diseases. We do carry the Preventic collars but most people today opt for the topical Frontline.

FOGGERS and SPRAYS for the house and yard are useful in controlling the balance of your tick population. Newer foggers have time-release agents and providing kill for weeks after application. Many contain growth regulators to inhibit the hatching of eggs already in the environment. Foggers also apply their chemicals EVERYWHERE which happens to be where the ticks live, so these can be very useful in getting a bad tick problem quickly under control. Many sprays work in similar fashion but are better suited for direct application to baseboards and bedding areas where the heaviest infestations will occur.

Spaying the yard, grass, fences, patios and dirt areas with a yard spray made for ticks is also important to get tick problems under control. Spraying may be needed every 7-10 days in warmer weather, and you can do it yourself or hire professional exterminators to do the job for you. Be careful to keep your dogs away from freshly sprayed areas until they are dry. Most veterinarians will carry high quality yard sprays for home use.

LICE

Lice are an uncommon parasite of dogs, being seen most frequently on dogs kept in very dirty and run down environments. There are two types of lice: chewing lice, which feed on scales of skin and sucking lice which suck blood from their hosts. These pests cause intense itching and often hair loss as the dog tries to scratch them off. They are small but can be seen with a magnifying glass and small white eggs can be found attached to hair shafts. Lice are host specific so there is no concern for people or other pets becoming infested. ((Louse))

Trichdectes canis is the chewing louse of dogs. Eggs are laid bonded to hair shafts, hatch into nymphs, molt three times and repeat the cycle. This may take only 3-4 weeks; the entire life of this parasite can be spent on one dog. Linognathus setosus is the sucking dog louse. Its life cycle is exactly the same as the chewing louse, but this parasite sucks blood from the dog and can cause a severe anemia if present in large numbers.

As lice live only on the dog, not in the environment, and as they are not very resistant to insecticides, dipping the dog every 10 days for 4-5 weeks in most any good quality flea/tick dip should do the trick. If the dog is unclean, a good bath before dipping will improve the success of these treatments. Although lice must live on their canine host, infested bedding should be destroyed and one spraying of the environment with a yard and kennel spray should kill any stray parasites.

MITES

Mites are small, eight legged parasites related to ticks and spiders. They are usually microscopic but cause very intense irritation as they burrow, dig and feed in and on skin surfaces. Infestation with mites is called Mange, with the type of mange designated by which mite is causing the infestation, such as Sarcoptic mange.

Demodex canis is a long, cigar-shaped mite that can burrow deep into the skin and feed at the roots and tissues surrounding hair follicles. While the mite may reside on most dogs, only a few animals will develop an active infestation leading to changes in the skin. This suggests that there is a genetic, inheritable predisposition to have this disease. Dogs with demodectic mange, even if they recover, should be spayed or neutered and not bred, ever. Young dogs as well as older dogs with serious internal diseases are most often affected. ((Demodex Mite))

While the mites are transmitted from dog to dog by casual contact, the mite will spend its entire life cycle on the host dog. Adults lay eggs that hatch into larvae, molt into nymphs and the nymphs molt three more times before becoming adults. If active disease occurs, it will assume one of two forms: 

LOCALIZED DEMODICOSIS has symptoms of loss of hair in patches near the eyelids, around the lips and corners of the mouth and on the forelegs. It will often not be itchy and some cases may heal spontaneously without treatment. Diagnosis is based on clinical signs and deep skin scrapings. Some cases will not heal and will progress by spreading to larger areas on the body.

Starting as the localized for of the disease, signs progress to larger patches that occur on the head, legs and body. As more damage is done to the skin and as secondary bacterial infection invades, ulcers, crusts and frankly infected sores will appear. The skin may become thick and rough and areas of infection can be very severe. Some cases of generalized demodicosis may become so severe and so resistant to treatment as to necessitate euthanasia to end the suffering of the animal. Diagnosis is as previously described.

Some authors advise doing nothing for localized cases unless they continue to spread. Others have found that dipping with Mitoban once or twice and/or daily application of Goodwinol ointment for three weeks will help improve results.

Dogs with generalized disease need intensive treatment to enact a cure. Clipping the hair short and scrubbing away crusts and scabs with a medicated shampoo is needed. Antibiotic therapy for 3-6 weeks to control skin infection is also very important in most cases. Dipping with Mitoban every 10-14 days until successive skin scrapings reveal no live mites present is required as the mainstay of therapy. Some dogs may take months to cure and a few will relapse after treatment has ended. Other treatments being tried include using Ivermectin, Interceptor or immunostimulating agents to enhance the effectiveness of the dips.

Sarcoptic mange is a very intensely itchy dermatitis of dogs and sometimes man. Mites burrow into the skin of the dog anywhere on the body, but prefer the ear margins, groin and axilla. Perhaps no other disease will cause as intense a discomfort as will these mites. ((Sarcoptic Mange))

Sarcoptes scabiei var. canis is a round, spider-like mite known for having tiny suckers at the end if it's legs. The mite must live on the host to survive. Adults lay eggs in tunnels in the skin, which hatch into larvae that molt into nymphs; nymphs molt twice more before becoming adults. The whole cycle takes only 14-21 days.

Clinical signs include intense itching, loss of hair, scales, small bumps on the skin and a generalized musty odor to the dog. Areas of deep abrasion may be present from self-trauma due to scratching. Diagnosis is based on observation of the above described skin lesions and demonstration of the mites in skin scrapings.

Dipping several times with most high-quality tick dips should cure the problem. One or two dips in Mitoban will usually work, as will dipping in lime-sulfur dips which is often avoided due to the terrible smell. Treatment with ivermectin has proven helpful in some cases and may be used with or without dipping. Treatment of infection with antibiotics and the itching with cortisone is often necessary and helpful.

Often called "walking dandruff", the mite Cheyletiella yasguri is a rather large mite often seen in young puppies from dirty, crowded conditions. It is called walking dandruff because it will appear to the naked eye that the dog has extremely scaly, flaky skin. When seen under the microscope, the scales are found to be mites. The mites cause symptoms of mild itching and can be transmitted to other dogs by casual contact. The mite spends its entire life cycle on the dog laying eggs and molting from larvae to nymph to adult, as do other mites. The eggs are laid glued to the hair shafts, which your vet may be able to identify under a microscope for a diagnosis. ((Cheyletiella))

Cheyletiella mites are easily killed with most dips or shampoos made for flea and tick control. Weekly baths or dips for 2 or 3 weeks should resolve the problem. As the mites can live off the dog for some time, spraying or powdering the bedding areas should often be undertaken.

Ear mites are probably the most over diagnosed problem of the ear. As often the mites cause a buildup of black, crusty debris in the ears, every time a dog owner notes this type of exudate the diagnosis seems automatic. Most commonly, ear canal infections that produce similar exudates are present.

Ear mites are caused by the mite Otodectes cynotis that is common to both the dog and cat but does not attack humans. The mites burrow and feed within the ear canal, which in itself can cause signs of intense itching, but as time goes on and the mites multiply, infection of the ear canal and allergic reaction to the mites can occur, compounding the problem all the more so. ((Ear Mite))

The mites can easily move between animals with even minimal contact but cannot live for long without a host. The mites also lay eggs in the ear canal, which hatch and molt into adult mites about every 19 days. Diagnosis is bases on clinical signs and visualization of the mites under the microscope; a procedure called ear cytology.

Ears should be cleaned and free of wax and debris. Nolvamite or Mitox are two common preparations that are used to kill mites in the ear and should be used for three weeks to be certain all mites, including the ones which hatch out, are killed. Ivermectin injections and topical applications have been used with relatively good success. Infections caused by the mites may also need to be treated with antibiotic or anti-yeast preparations. Applying flea powder to the neck and body of your dog also helps to quickly reduce the ear mite population present.

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