Ticks and Mites

Dermacentor spp., Ixodes spp, Rhipicephalus sanguineus, Cheyletiella spp., Demodex spp., Otodectes cynotis, Sarcoptes scabei

Species of veterinary importance for dogs and cats in Canada are D. variabilis and D. andersoni.

Host range: Dogs and cats serve primarily as hosts for the adult stage of these ticks. Occasionally domestic pets will be infested with tick nymphs. A wide range of wildlife hosts sustain larvae, nymphs and adults of these ticks and serve as a reservoir for domestic animals and people.

Geographic range: Widespread with D. variabilis is found in Alberta and east and D. andersoni found Alberta and west into British Columbia.

Life-cycle: D. variabilis and D. andersoni are both three-host ticks, feeding on three unique hosts in the course of their lifespan, with moulting or egg laying occurring in the environment post feeding. Tick larvae and nymphs tend to prefer smaller hosts, rodents and birds, with adults having a preference for larger animals including dogs, cats and people.

Diagnosis: Observing one or more of these large ornate reddish brown ticks attached to a host is the primary method of diagnosis. Dogs and cats with moderate to heavy infestations may have irritated skin, hair loss and possibly anemia. These ticks have been associated with tick paralysis.

Management: Preventing access to semi-wild to wild areas during the seasons these ticks are active can be helpful. As well there are numerous highly efficacious topical and oral tick treatments available. These ticks are known to transmit numerous pathogens including Rocky Mountain Spotted Fever, Colorado Tick Fever and tularemia. These ticks are not associated with the transmission of Lyme disease.

Species of veterinary importance for dogs and cats in Canada are I. scapularis and I. pacificus. There are other Ixodes species found in Canada but these are primarily found on wildlife and only rarely cross to domestic animals.

Host range: Dogs and cats serve as hosts for both nymph and adult life stages of this tick. A wide range of wildlife hosts sustain the larvae, nymphs and adults of these ticks and which then serve as a reservoir for domestic animals and people.

Geographic range: I. pacifcus is found on the lower mainland and Vancouver Island in British Columbia. I. scapularis is found in endemic populations in southern Manitoba, in much of southern Ontario and Quebec and into New Brunswick and Nova Scotia. Ixodes scapularis is found in other parts of the country on a regular basis. These ticks in non-endemic areas are thought to be brought in by migrating birds. The I. scapularis population size and geographic distribution in Canada are increasing, likely due in part to climate change causing environmental conditions to become more suited to their requirements.

Life-cycle: These are three host ticks, feeding on three unique hosts in the course of their lifespan, with a moult or egg-laying occurring in the environment post feeding. Tick larvae prefer smaller hosts while the nymphs and adults will feed on a variety of larger hosts including dogs, cats and people.

Diagnosis: Observing one or more of these small inornate ticks attached to a host is the primary method of diagnosis.

Managment: Preventing access to semi-wild to wild areas during the seasons these ticks are active can be helpful. As well there are numerous highly efficacious topical and oral tick treatments available. These ticks transmit the pathogens associated with Lyme disease and with the pathogens associated with tularemia, ehrlichiosis, and anaplasmosis.

Host range: Dogs are the preferential host for all life  stages of R. sanguineus. This tick will only rarely feed off other hosts including people.

Geographic range: Rhipicephalus sanguineus, is probably the most cosmopolitan tick in the world but is relatively rare in Canada. It is found mainly in Quebec and Ontario. There has been an increased incidence of this parasite as more dogs are traveling with their owners to tropical and semi-tropical destinations and then bringing the ticks back home.

Life-cycle: This is a three host tick with each stage leaving the host to moult prior to finding another host. Dogs are the preferential host and all three life stages, larva, nymph and adults may be found on a single dog. Rhipicephalus sanguineus is able to complete its life-cycle outdoors in warmer areas of the world, but in can also complete its life-cycle indoors in regions with cooler climates.

Diagnosis: Finding these medium sized brown ticks on dogs is the primary diagnostic method. Dogs generally do not display clinical signs when infested.

Management: Keeping pet dogs away from places where infested dogs may be or have been present is an effective control measure. This may include kennels and houses. As well there are numerous highly efficacious topical and oral tick treatments available. This tick is a vector for canine piroplasmosis (Babesia canis and possibly Babesia
canis gibsoni) and canine pancytopenia (Erlichia canis).

Cheyletiella spp., Demodex spp., Otodectes cynotis, Sarcoptes scabiei Cheyletiella spp.

Host range: Dogs and cats each have their own species of the mite Cheyletiella, which appear to be host-specific – C. yasguri in dogs and C. blakei in cats.

Geographic distribution: Cheyletiella occurs on these hosts around the world. Distribution in Canada is not well documented but there is probably variation in occurrence in different regions of the country.

Life-cycle: The entire life cycle of the mites, adults, eggs and larval stages, occurs on the host.

Diagnosis: The mites can be easily seen moving around in the haircoat – “walking dandruff”. In general, dogs are more likely to show clinical signs (primarily pruritis, scaliness and eczema-like skin lesions around the face), than are cats. Cheyletiella transmits readily to people, who can show clinical signs in the absence of signs in the pet, or before such signs develop.

Management: Infestations can be acquired from other animals but mites may survive for some time in the environment so may be present even if infested animals are not. It is important to thoroughly clean bedding etc. once a treatment regime has started. Although there are no products labelled for treatment of these mites in dogs, some insecticides and topical and oral acarcides have been found to be effective.

Host range: Demodex mites are common in the hair follicles and sometimes sebaceous glands of the skin of dogs and cats.

Geographic distribution: The mite is found worldwide.

Life-cycle: The entire life-cycle of the mite occurs on the host. Probably most dogs and cats are infested and they acquired the mites from their dams while nursing.

Diagnosis: The mites can often be found using a deep skin scraping. Very few infested animals will display symptoms of mange of which there are three clinical presentations 1) localized (one or more isolated lesions) – often resolves spontaneously; 2) generalized (some, most, or all of the skin surface affected) – does not resolve spontaneously and can be difficult to treat successfully; and 3) pododemodecosis –affects the feet.

Management: Demodectic mange in dogs is most common in young animals and has three main clinical presentations: Generalized demodectic mange in an older dog often signals underlying disease. Pruritus is not a common feature of demodectic mange unless there is secondary bacterial infection, which is common with the generalized form of the disease. Isoxazalines seem to be effective in resolving demodectic mange in dogs. Treatment in cats involves the use of macrocyclic lactones or
lime-sulfur dips.

Host range: The ear mite Otodectes cynotis infests dogs and cats and several free-ranging carnivores.

Geographic distribution: This parasite is found worldwide.

Life-cycle: The entire life-cycle occurs on the host. Transmission is via direct contact with other infected animals and possibly fomites

Diagnois: Clinical signs include intense pruritus, scratching and rubbing at the ears, head shaking and sometimes severe behavioural disturbances and seizures. Examination of the ear canals reveals a waxy then crusty exudate. Ear swabs examined under a microscope may reveal the presence of mites.

Management: Numerous treatments are available. Ear cleaning is advised

Host range: Adult mites of the genus Sarcoptes live in the stratum corneum of the skin of mammals. Specific subspecies (or strains) are found on dogs.

Geographic distribution: This parasite is found worldwide.

Life-cycle: The entire life-cycle occurs on the host. Transmission is via direct contact with other infected animals and possibly fomites. The infestation is highly contagious

Diagnosis: Clinically, sarcoptic mange (scabies) is characterised initially by intense pruritus and erythema and papulocrustous eruptions, and later by a range of pathological changes in the skin including particularly epidermal hyperplasia. Deep skin scraping and microscopic examination may reveal the mites.

Management: Macrocyclic latones and isoxazalines may be used to treat and control this parasite.