Sarcoptes scabiei var canis infestation ("scabies") is a highly contagious disease of dogs found worldwide.
Diagnosis is based on the history of severe pruritus of sudden onset, possible exposure, and involvement of other animals, including humans. Making a definitive diagnosis is sometimes difficult because of negative skin scrapings. Concentration and flotation of several scrapings may increase chances of finding the mites, eggs, or feces. Several extensive superficial scrapings should be done of the ears, elbows, and hocks; nonexcoriated areas should be chosen.
The mites are fairly host-specific, but animals (including humans) that come in contact with infested dogs can also be affected. Adult mites are 0.3-0.5 mm long, roughly circular in shape, without a distinctive head, and have 4 pairs of short legs. Females are almost twice as large as males. The entire life cycle (17-21 days) is spent on the dog. Females burrow tunnels in the stratum corneum to lay eggs. Sarcoptic mange is readily transmitted between dogs by direct contact; infestation by indirect contact is less frequent but may occur. The incubation period is variable (10 days to 8 wk) and depends on level of exposure, body site, number of mites transmitted, and individuals.
Treatment can be either topical or systemic, and should include all dogs in contact. For topical treatment, hair can be clipped, the crusts and dirt removed by soaking with a good antiseborrheic shampoo, and an acaricidal dip applied. Lime-sulfur is highly effective and safe for use in young animals; several dips 5 days apart are recommended. Phosmet has been successfully used according to label instructions. Amitraz is an effective scabicide, although it is not approved everywhere for this use, and there have been some reports of lack of efficacy. Fipronil spray was reported to be effective but should be considered an aid in the control rather than a primary therapy. Systemic treatments of scabies are based on the administration of macrocyclic lactones. Among them, only selamectin is approved for this use; it is given as a spot-on formulation at 6 mg/kg twice at a 1-mo interval. This drug appears to be safe, even in ivermectin-sensitive Collies, and is the systemic treatment of choice. Other endectocides, such as moxidectin and ivermectin, which are not registered for the treatment of sarcoptic mange in dogs, have been reported to be quite effective depending on the dosage and route of administration. Ivermectin (200 µg/kg, PO or SC, 2 treatments 2 wk apart) is very effective and usually curative. Ivermectin at this dosage is contraindicated in Collies and Collie crosses. Idiosyncratic reactions in other breeds may also occur. Additionally, the heartworm status of the dog should be evaluated before treatment.
[no breeds in our database]
[no information in our database]
