External Parasites

External parasites are those that live on the outside of the body. A few of the most common external parasites that affect dogs and cats are fleas, lice, mites and ticks.

Fleas: Fleas are one of the most common parasites in Canada. Did you know there are dog, cat, poultry and "human fleas"?

Not only do fleas cause your pet to be very uncomfortable and irritated, they can also cause other health problems. Fleas can carry tapeworm and dogs and cats can acquire a tapeworm infection if they ingest a flea. Although this may seem strange, it is quite common for a pet to ingest a flea based on how they bite their itchy skin when infested with fleas. Dogs and cats can develop an allergy to flea bites (flea allergy dermatitis) causing severe skin irritation and eventually skin infections. In severe flea infestations, animals may become anemic (low red blood cells) and even die. The tapeworm carried by fleas can infect children who accidently swallow a flea http://www.capcvet.org/capc-recommendations/fleas/

Fleas can also be carriers of blood borne diseases, which can be very serious. Murine typhus, cat scratch disease, plague, and flea typhus are important zoonoyic diseases that fleas play an important role in certain regions. http://www.capcvet.org/capc-recommendations/fleas/

The adult flea deposits eggs on the host. The eggs fall off the host and develop into larva. The larva matures, spins a cocoon and pupates. The adult flea will then exit the cocoon. Adults can take as little as 2 weeks to exit the cocoon or as long as one year. Flea life cycle: http://www.capcvet.org/capc-recommendations/fleas/

We recommend a comprehensive flea-control program. The program should eliminate fleas on pets, eliminate existing environmental infestations, and prevent subsequent reinfestation. Because proper treatment of your pet and home can be an unexpected expense, taking a preventative approach to flea control saves you money, time and discomfort for your pet.

More flea info at: https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951999

Mites: Mites are a common cause of itching and scratching in dogs and cats. They are microscopic and therefore require a microscope to be seen. There are a variety of mites, but the 3 most common species that cause disease in dogs and cats include Demodex, Sarcoptes and Otodectes.

Demodex mange or demodicoses can be localized (only a certain area is affected) or generalized (whole body is affected). Both forms can affect young dogs and adult dogs. Normal dogs have a small number of demodex mites on their bodies and do not cause them any harm. It is when there is an overgrowth of mites that disease develops. An overgrowth occurs then an animal has an underlying disease, an immune defect or an underdeveloped immune system, such as with puppies.

Localized demodicosis is characterized by patchy hair loss on the head or limbs and will often occur in puppies less than six months of age. Generalized demodicosis can cause significant disease characterized by hair loss, skin redness and skin infections. Dogs who develop secondary bacterial infections are usually very itchy. Demodicosis is diagnosed by microscopic examination of deep skin scrapes from affected areas of hair loss. Various treatments are available based on the type and severity on demodex mange.

For more information on demodectic mange, please visit http://www.capcvet.org/capc-recommendations/demodex-mange-mite/ and https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951505

Sarcoptic mange or scabies is a fairly common skin mite that causes dogs and cats to be extremely itchy. This is due to the motion of the mite under the skin and in addition, the eggs and mites can cause an allergic reaction.

Sarcoptic mites prefer hairless skin or less haired areas. The ear pinnae, elbows and abdomen are most likely to be affected. The skin on these areas will become red, scaly and very itchy. It is important to note that sarcoptic mange can be transmitted to other animals by direct contact. People can become infested with the mites present on their dogs. The lesions that are produced will be highly itchy but will almost always clear without the need of specific treatment for the mite infestation.

Sarcoptic mange is diagnosed by microscopic examination of deep skin scrapes from affected areas of hair loss. There may be cases where severe skin disease can occur even though repeated skin scrapings recover no mites. Various treatments are available.

For more information on sarcoptic mange, please visit http://www.capcvet.org/capc-recommendations/mites-other-than-demodex/ and https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951492

Otodectes mites ( Ear Mites):  Ear mites are small mites that live and reproduce in the ears of cats and dogs. They cause intense itching, inflammation and result in ear infections. When an animal has an ear infection due to ear mites, the ears will contain thick, black discharge that resembles coffee grounds. Not all animals that have ear infections will have ear mites. Ear mites are much more likely to occur in cats with infections, whereas dogs will have ear infections due to other causes.

Otodectes mites are spread by direct contact between animals. Diagnosis is made on clinical signs and examination of an ear swab under the microscope. Please see your veterinarian if your pet is exhibiting clinical signs of an ear infection so ear mites can be ruled out. Ear mites can be treated but it is important to understand that most over the counter products to treat mites are ineffective often leading to weeks of inappropriate treatment.

For more information on ear mites, please visit  http://www.capcvet.org/capc-recommendations/mites-other-than- demodex/ and  https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951535 

Cheyletiella mites: Also known as "Walking dandruff" or "Hairclasping Mite" , Cheyletiella mites are non-burrowing mites that live on the skin of dogs and cats, feeding off the keratin layer of the skin. Cheyletiella mites are very mobile and transmitted by direct contact. The mites can be very irritating to affected animals, and people can get bitten by the mites but develope infestations.

For more information on Cheyletiella please visit: http://www.capcvet.org/capc-recommendations/hairclasping-mite/ 

Lice: There are two types of lice biting and chewing. Lice are not frequently seen on dogs and cats in our area but are most frequently associated with unsanitary conditions and in very young, old or debilitated animals.

Because lice are extremely host specific, lice of dogs and cats will not affect people.

One dog louse Trichodectes canis can act as a vector of the dog tapeworm Dipylidium caninum. In general lice cause skin irritation with resultent scratching and dermatitis.

For more information on Lice please visit: http://www.capcvet.org/capc-recommendations/lice/ 

Ticks: In general ticks are an important transmitter of diseases to dogs cats and people.  There are both hard ticks (Ixodidae sp) and soft ticks (Argasidae sp), with each group having a number of different species. Each species has a different geographic distribution. The "brown dog tick" (Rhipicephalus sanguineus) is the only tick that can complete it's life cycle in your home, and significant household infestations can occur.

In severe infestations ticks can result in anemia, as all stages of the ticks life cycle feed on blood. Typically irritation and pruritus occurs at the tick site. Tick paralysis is caused by a neurotoxin produced by the female of several  tick species (Dermacentor andersoni and Dermacentor variabilis).

Tick transmitted  diseases like Tuleremia, Ehrlihia, Rocky Mountain Spotted Fever, Lyme disease, and Anaplasmosis are important concerns in various regions  for dogs, cats and people. Where you and your pet live and travel to, determine the importance of tick control.

Pet owners, parents and people who frequent the outdoors are urged to visit the  Companion Animal Parasite Council for more general information regarding ticks, public health considerations and tick control. http://www.capcvet.org/capc-recommendations/ticks/