Feline ectoparasitic diseases—Part 1: Clinical signs and diagnosis

Feline ectoparasitic diseases— Part 2: Treatment and preventive measures

3 9

A peer-reviewed publication www.banfield.com/banfield-journal

Banfield JournalVol. 10 No. 2 Summer 2014

Achieving Success in Practice®

FELINE PARASITES

The Banfield Journal is getting a makeover!

Don’t miss out!We’ll alert you when new clinical articles and resources

are available at banfield.com/banfieldjournal. Just provide us your email address and we’ll keep you up to date!

Sign Up

Summer 2014 1

Inside This Issue

Achieving Success in Practice®

Banfield JournalVol. 10 No. 2

SUMMER 2014

Feline ectoparasitic diseases— Part 1This review covers the clinical signs of common feline parasite infestations and diagnostic methods used for the detection of these parasites.Katherine Doerr, DVM, DACVD

Feline ectoparasitic diseases—Part 2Feline ectoparasitic disease is eminently curable; thus, it's very important to rule out parasitic disease early in the diagnostic process with appropriate cytological samples or therapeutic trials.Katherine Doerr, DVM, DACVD

3

9

For more information about the Banfield Journal, please call (866) 262-7387or email: banfieldjournal@banfield.com

ABOUT THE COVER: Feline ectoparasites are a common cause of pruritis in cats. Illustration by Laurie O’Keefe, medical and biological illustrator.

Sour

ce: I

mag

e co

urte

sy o

f UC

Davi

s VM

TH D

erm

atol

ogy

Serv

ice

Sour

ce: i

Stoc

kpho

to.co

m

2 Banfield Journal www.banfield.com/banfield-journal

Welcome to the summer 2014 edition of the Banfield Journal. In this issue, author Katherine Doerr, DVM, DACVD, presents a two-part series covering the diagnosis, treatment and

prevention of feline ectoparasitic diseases, which are a common cause of pruritus in cats.

In her first article, Dr. Doerr notes that when evaluating a pruritic cat, specific diagnostic steps are necessary to rule out certain ectoparasites. She reviews the clinical signs of common feline parasite infestations and diagnostic methods used for the detection of these parasites. Dr. Doerr’s second article focuses on treatment and preventive measures once parasites have been confirmed. The duration of therapy is dependent on the stages and length of the parasite’s life cycle in order to ensure that any eggs laid by adults do not hatch into adults prior to the discontinuation of treatment. Therefore, proper therapy is vital in obtaining parasitological cure. Dr. Doerr’s useful table in this article reviews the therapeutic agents used for the treatment and/or prevention of parasites causing dermatologic disease in cats. Also, be sure to take a look at the images included in this article, as they will give you a clearer picture of these bothersome pests. Look for our new online-only format beginning this summer. We’ll be presenting our professional content and resources in new ways. We'd like to alert you when new clinical content is available online. If you are interested in receiving these notifications, please send your email address to: banfieldjournal@banfield.net. This edition and past issues of the Banfield Journal are available online at www.banfield.net/banfield-journal. Enjoy!

Sharon DeBusk, Editor/Publisher sharon.debusk@banfield.net

Karen Faunt, DVM, MS, DACVIMVice President,Medical Quality Advancement,Banfield, Portland, Ore. Heather Fees, DVMMultiple CharterHospital Owner inColumbus, Ohio, area Gary Goldstein, DVM, FAVD, DAVDCAssociate Medical Director,University of Minnesota Veterinary Medical Center,St. Paul, Minn.

Sharon M. HarmonExecutive Director,Oregon Humane Society,Portland, Ore.

Jeffrey Klausner,DVM, MS, DACVIMSenior Vice President/Chief Medical Officer, Banfield, Portland, Ore.

Jon Plant, DVM, DACVDBoard-certified Veterinary Dermatologist,SkinVet® ClinicLake Oswego, Ore.

Elizabeth Lund, DVM, MPH, PhDSenior Director of Research, Banfield Applied Research & Knowledge team (BARK),Banfield, Portland, Ore.

Advisory Board

EDITORIAL MISSION To enrich the lives of general

practitioners, paraprofessionals and veterinary students

by providing the information to succeed in veterinary practice.

EDITOR/PUBLISHER Sharon DeBusk

MEDICAL WRITER/COPY EDITOR Nina Silberstein

GRAPHIC DESIGNEREric Jensen

MEDICAL ADVISORS/REVIEWERSDavid Dilmore, DVM

Robyn Hauser, DVM, DABVP Sandi Lefebvre, DVM, PhD

Elizabeth Lund, DVM, MPH, PhDAlison Marsh, DVM, JD

Deborah Miller, DVM, DABVPThomas Mohn, DVM, DABVP Patrick Shearer, BVMS, PhD

Rachel Beck, CVT Ashlee Addleman, MPH

BANFIELD PET HOSPITAL®

Tony Ueber President & CEO

BANFIELD PET HOSPITAL® EDITORIAL OFFICES

8000 N.E. Tillamook St.Portland, OR 97213

INFORMATIONTo inquire about

the Banfield Journal, please call (866) 262-PETS (7387)

or email us at: banfieldjournal@banfield.net

All rights reserved. Reproduction in whole or in part

without express written permission is prohibited.

© 2014 Banfield Pet Hospital®

Banfield JournalSummer 2014 • Vol. 10 No. 2

From The Editor

Summer 2014 3

Feline ectoparasites are a common cause of pruritus in cats. When evaluating a pruritic cat, specific diagnostic steps are necessary in order

to rule out certain ectoparasites. The most common parasites that can cause dermatological disease in cats include helminths, arthropods and insects. Clinical signs in cats may be due to the parasite itself; however, there are many parasites that evoke a hypersensitivity response in some individuals, resulting in severe symptoms. The following two-part series focuses on the clinical signs, diagnosis, and therapeutic and preventive measures of the most common arthropod and insect parasites of felids.

CLINICAL SIGNS AND DIAGNOSISArthropodsThe most common arthropods that cause dermatological disease in cats include Otodectes cynotis, Cheyletiella blakei, Notoedres cati and Demodex spp. Less common arthropods include Sarcoptes scabiei, ticks and mites (such as Dermanyssus spp. and Lynxacarus spp.).

BY KATHERINE DOERR, DVM, DACVDCONTRIBUTING AUTHOR

Otodectes cynotis Otodectes cynotis is the most common mite infestation in the cat. The oval-shaped non-burrowing mite proceeds through a direct life cycle that involves an egg, larvae, protonymph and deutonymph that then molts into a microscopic (450-630 nm) adult.1 Completion of the life cycle takes about 21 days. Cats usually present with a significant amount of dry, black-brown ceruminous debris emanating from the ear canal. Occasionally, there may be crusted papules and excoriations around the face and neck. Pruritus is marked. Rarely, Otodectes cynotis can cause pruritus of the trunk and arms of humans.2 Diagnosis in the cat is made via microscopic examination of the cerumen immersed in mineral oil at 10X magnification.

Cheyletiella blakei Cheyletiellosis (“walking dandruff”) in cats is usually due to the arthropod Cheyletiella blakei. However, other species may also infest cats.3-5 This large (385 µm) mite lives in the keratin layers of the skin and goes

ECTOPARASITIC DISEASES

Feline

4 Banfield Journal www.banfield.com/banfield-journal

neck, trunk and limbs.24 Occasionally, the cat may present with a ceruminous otitis externa.11 Diagnosis is usually achieved by a deep skin scraping or trichogram evaluated on mineral oil at 10x magnification or histopathology. The mite is long (182-292 µm) with a similar morphology to Demodex canis.19 Demodex gatoi is located in the superficial keratin layers of the skin.25 Clinical signs consist of intense pruritus that is usually poorly responsive to corticosteroids. There may also be self-induced alopecia of the thorax, abdomen and medial thighs. The exposed skin may be erythematous and have adherent scale, or it may be hyperpigmented secondary to chronic inflammation. Rarely, a cat may present with indolent lip ulcers.26 A superficial skin scraping, evaluated at 10x magnification, is the best diagnostic modality for confirmation of a superficial demodex infestation. Diagnosis can be difficult, as skin scrapings may be negative in some cases; thus, the final diagnostic test may be response to therapy.27 Not much is known about the unnamed Demodex spp. of the cat at this time. However, the mite has been reported to have caused an outbreak in an animal shelter as a concurrent infestation with D. cati.19,28 The mite is thought to be follicular, as it was found along hair shafts microscopically.19

INSECTSFelicola subrostratus Felids can be affected by many insect parasites, with the most common being lice and fleas. Pediculosis in the cat is usually due to the biting louse, Felicola subrostratus. This louse is host-specific and spends its entire 14- to 21-day life cycle on the host. Lice infestations are more common in the winter as the higher temperatures in the summer can be deadly to the lice. Some cats may harbor this parasite with no clinical signs, while others may have severe pruritus, excoriations and dorsal alopecia.29 Diagnosis is accomplished via clear acetate tape impression, superficial skin scrapings or flea combing.

Ctenocephalides felis felis Fleas are an extremely common cause of dermatological disease in cats. Ctenocephalides felis felis is the most common species of flea infesting cats.30 Fleas can consume 10 to 15 times

through a 21-day life cycle.4-6 Clinical signs can vary from mild to severe pruritus, varying degrees of non-adherent to adherent scale and miliary dermatitis.5,7

All species of cheyletiella are zoonotic and can cause erythematous macules, papules and pustules in humans.8 Diagnosis of cheyletiellosis can be achieved by direct examination, clear acetate tape, flea comb contents examination or fecal exam.6

Notoedres cati and Sarcoptic scabiei Sarcoptic mange in the cat is most commonly due to Notoedres cati; however, there have been some reports of Sarcoptes scabiei in cats.9-15 These mites proceed through a direct life cycle consisting of the egg, larvae, nymph, and then adult, which takes about 17-21 days. Cats infected with Notoedres spp. are usually intensely pruritic, while cats infested with Sarcoptes spp. may be non-pruritic but have thick crusts like “Norwegian scabies.”15 Pruritus is most commonly located around the head and neck, but can extend to the dorsum and limbs. Humans, while not the appropriate host for these mites, may get an erythematous papular eruption that should resolve within two weeks.16 Superficial skin scraping is the diagnostic method of choice; however, it has only a 50 percent success rate in recovering Sarcoptes spp. and only a slightly higher chance of recovering Notoedres cati.17 The contents of the scraping are placed on mineral oil and evaluated under 10x magnification and low light. Sarcoptes scabiei mites are a 200-400 µm, oval-shaped mite with a terminal anus, while Notoedres cati is smaller (150-230 µm), has more body striations and a dorsal anus.18 A therapeutic trial may be necessary, as scrapings may yield negative results.

Demodex spp. Demodectic mange in the cat can be due to three different species of mite: Demodex cati, Demodex gatoi and an unnamed demodex mite.19-21 They all go through an 18- to 24-day life cycle consisting of an egg, larva, nymph and adult. D. cati is a follicular mite that can be localized or generalized.22 Burmese and Siamese cats are most commonly affected.23 Pruritus is variable and the lesions usually consist of erythema, patchy alopecia, comedones, scale and crusting, most commonly affecting the head,

Summer 2014 5

their bodyweight in blood in a single day.31 They go through complete metamorphosis that can take 12 to 174 days.32 The eggs, which are laid on the host, hatch to larvae that pupate and then evolve into an adult. Clinical signs are variable and dependent upon the host’s hypersensitivity to flea salivary antigen, the number of parasites present and the host’s tolerance for irritation. Miliary dermatitis is a common reaction pattern for flea bite hypersensitivity; furthermore, the patient may also have excoriations, alopecia, erythema, and rarely, anemia due to blood loss.29 Diagnosis of flea infestation is by direct examination, detection of flea excrement and live fleas seen via flea combing.

CONCLUSIONParasites should be considered as differential diagnoses in the diagnostic work-up of any cat with dermatological disease. Investigation of feline dermatologic parasites can be accomplished quickly and simply, using diagnostic techniques such as skin scrapings, microscopic examination of skin/otic material and acetate tape impressions. See Table 1. Coupled with the use of therapeutic trials when necessary, many parasites can be quickly ruled in or out. In the next article, we will examine the various options available for treatment and prevention of feline dermatologic parasites.

Table 1: Clinical signs of common feline parasite infestations and diagnostic methods used for detection

Parasite Clinical signs Diagnosis Comments

Otodectes cynotis

Dry, black-brown ceruminous debris in the ear canal;marked pruritus;occasionally crusted papules and excoriations around face and neck

Microscopic examination of the cerumen at 10x; immerse cerumen in mineral oil, liquid paraffin or chloral lactophenol

Cheyletiella blakei

Mild to severe pruritus;varying degrees of non-adherent to adherent scale;miliary dermatitis

Direct examination;clear acetate tape;flea comb contents examination orfecal exam

Notoedres cati Intense pruritus, most commonly around the head and neck

Superficial skin scraping;contents of the scraping are placed on mineral oil and evaluated under 10x magnification and low light

Only a 50 percent success rate in recovering mites; therapeutic trial may be necessary

Sarcoptes scabiei

May be non-pruritic;may have thick crusts like “Norwegian scabies”

As above As above

Demodex spp.

D. cati Localized and generalized forms;pruritus is variable;lesions usually consist of erythema, patchy alopecia, comedones, scale and crusting; lesions usually affect the head, neck, trunk and limbs

Deep skin scraping or trichogram evaluated on mineral oil at 10x magnification or histopathology

May occasionally present with a ceruminous otitis externa;therapeutic trial may be necessary

D. gatoi Intense pruritus that is usually poorly responsive to corticosteroids;may also be self-induced alopecia of the thorax, abdomen and medial thighs

Superficial skin scraping evaluated on mineral oil at 10x magnification

Therapeutic trial may be necessary

Felicola subrostratus

May have no clinical signs; other cats may have severe pruritus, excoriations and dorsal alopecia

Clear acetate tape impression, superficial skin scrapings or flea combing

Ctenocephalides felis

Miliary dermatitis is a common reaction pattern for flea bite hypersensitivity;cats may also have excoriations, alopecia and erythema

Direct examination; detection of flea excrement seen via flea combing

6 Banfield Journal www.banfield.com/banfield-journal

References 1. Lohse J, Rinder H, Gothe R, et al. Validity of

species status of the parasitic mite Otodectes cynotis. Med Vet Entomol. 2002;16(2):133.

2. Herwick RP. Lesions caused by canine ear mites. Arch Dermatol. 1978;114(1):130.

3. Moriello KA. Treatment of Sarcoptes and Cheyletiella infestations. In: Kirk’s Current Veterinary Therapy XI: Small Animal Practice. Philadelphia, Pa. WB Saunders Co. 1998; 558-560.

4. Cohen SR. Cheyletiella dermatitis. A mite infestation of rabbit, cat, dog, and man. Arch Dermatol. 1980;116(4):435-437.

5. Moriello KA. Cheyletiellosis. In: Current Veterinary Dermatology. St. Louis, Mo. Mosby Year Book. 1993;90-95.

6. Paradis M, Scott DW, Villeneuve A. Efficacy of ivermectin against Cheyletiella blakei infestation in cats. J Am Anim Hosp Assoc. 1990;26(2):125-128.

7. Sosna CB, Medleau L. External parasites: Life cycles, transmission, and the pathogenesis of disease. Symposium on external parasites. Vet Med. 1992;87:538-547.

8. Lee BW. Cheyletiella dermatitis: A report of 14 cases. Cutis. 1991;47:111-114.

9. Lindquist WD, Cash WC. Sarcoptic mange in a cat. JAVMA. 1973;162(8): 639-641.

10. Bussiéras J. A rare case of sarcoptic mange in a cat. Pract Med Chirugicale. 1984;19:375-377.

11. Hawkins JA, McDonald RK, Woody BJ. Sarcoptes scabiei infestation in a cat. JAVMA. 1987;190(12):1572-1573.

12. Huang HP, Liang SL, Yang HL, et al. Sarcoptes scabiei infestation in a cat. Fel Pract. 1998;26(2):10-12.

13. Kontos V, Sotiraki S, Himonas C. Two rare disorders in the cat: Demodectic otitis externa and sarcoptic mange. Fel Pract. 1998;26(6):18-20.

14. Bornstein S, Gidlund K, Karlstam E, et al. Sarcoptic mange epidemic in a cat population.Vet Dermatol. 2004;15 (Suppl. 1):34.

15. Malik R, Stewart KM, Sousa C, et al. Crusted scabies (sarcoptic mange) in four cats due to Sarcoptes scabiei infestation. J Fel Med Surg. 2006;8(5):327-339.

16. Estes SA, Kummel B, Arlian L. Experimental canine scabies in humans. J Am Acad Dermatol. 1983;9(3):397-401.

17. Foley RH. A notoedric mange epizootic in an island’s cat population. Fel Pract. 1991; 19(5):8-10.

18. Bowman DD. Georgis’ Parasitology for Veterinarians. 7th edition. Philadelphia, Pa. WB Saunders Co. 1999.

19. Löwenstein C, Beck W, Bessmann K, et al. Feline demodicosis caused by concurrent infestation with Demodex cati and an unnamed species of mite. Vet Rec. 2005;157(10): 290-292.

20. Foley RH. Feline demodicosis. Compen Cont Educ. 1995;17(14):481-487.

21. Chesney CJ. An unusual species of demodex mite in a cat. Vet Rec. 1988;123(26-27):671-673.

22. Gabbert N, Feldman BF. A case report - Feline demodex. Fel Pract. 1976;6:32-33.

23. Stogdale L, Moore D. Feline demodicosis. J Am Anim Hosp Assoc. 1982;18:427-432.

24. Guaguere E, Muller A, Degorce-Rubiales F. Feline demodicosis: A retrospective study of 12 cases. Vet Dermatol. 2004;15 (Suppl 1):34.

25. Desch CE Jr, Stewart TB. Demodex gatoi: New species of hair follicle mite (Acari: Demodecidae) from the domestic cat (Carnivora: Felidae). J Med Entomol. 1999;36(2):167-170.

26. Morris D, Beale K. Demodicosis. In: Consultation in Feline Internal Medicine. Vol. 5. St Louis, Mo. Elsevier Saunders. 2006;247-250.

27. Beale K. Feline demodicosis: A consideration in the itchy or overgrooming cat. J Fel Med Surg. 2012;14:209-213.

28. Newbury S, Moriello K, Steinburg H. An outbreak of Demodex gatoi and an unnamed demodex mite in an open admission animal shelter. Proceedings of the 21st North American Veterinary Dermatology Forum. Palm Springs, Calif. 2001;188.

29. Miller W, Griffin C, Campbell K. Small Animal Dermatology. St. Louis, Mo. Elsevier Mosby. 2013;320-324.

30. Chesney CJ. Species of flea found on cats and dogs in south west England: Further evidence of their polyxenous state and implications for flea control. Vet Rec. 1995;136(14):356-358.

31. Kelly P, Rolain JM, Raoult D. Prevalence of human pathogens in cat and dog fleas in New Zealand. N Z Med J. 2005;118(1226):U1754.

32. MacDonald JM. Flea control: An overview of treatment concepts for North America. Vet Dermatol. 1995;6(3):121-130.

Summer 2014 7

Otodectes cynotis mitesA male (smaller mite) and female (larger mite) mating. The male’s copulatory suckers can be seen just above the end of the female mite’s abdomen. Right – Larval stage

Notoedres catiA cat infested with Notoedres cati, showing thick adherent crusts along pinnal margins, similar to “Norwegian Scabies”

Notoedres cati miteNote the dorsal anus, in comparison to Sarcoptes scabiei, which has a terminal anus

Sour

ce: A

ll im

ages

cour

tesy

of U

C Da

vis V

MTH

Der

mat

olog

y Se

rvic

e

8 Banfield Journal www.banfield.com/banfield-journal

Felicola subrostratus (cat louse)

Demodex cati

Flea larva emerging from an egg

Cheyletiella blakeiNote the prominent hooks on the end of the mouthparts (arrows)

Summer 2014 9

In the previous article, we discussed the clinical signs and common diagnostic modalities used to rule parasites in or out as differential diagnoses

for a cat with dermatologic disease. Once parasites have been confirmed, therapy of the appropriate type and length is paramount in ensuring parasitological cure. The stages and length of the parasite’s life cycle guides the duration of therapy, in order to ensure that any eggs laid by adult parasites do not hatch into adults prior to the discontinuation of treatment. In cats that live in an area endemic for certain parasites, preventive measures may be necessary in order to hinder infestation and potential transmission of vector-borne disease. Furthermore, some parasites are zoonotic, so taking preventive measures and ensuring appropriate treatment of the affected pet(s) is imperative for the client’s health and well-being.

ARTHROPODSOtodectes cynotisEffective treatment of Otodectes cynotis, the agent of otoacariasis, involves treating the affected patient

as well as any other in-contact pets.1 Topical otic preparations that contain 0.01 percent ivermectin or 0.1 percent milbemycin oxime are applied once in each ear and are FDA-approved for use in otoacariasis. Selamectin, applied topically between the shoulder blades, is also licensed for use against ear mites.2 Moxidectin and fipronil may also be beneficial.3,4 Prevention of ear mites in cats can be achieved with the topical use of selamectin once monthly. Furthermore, keeping cats away from potential carriers, such as in a shelter situation, is also important in preventing spread of the mite.

Cheyletiellia blakeiCheyletiella blakei is a highly contagious mite, so it is important to institute appropriate therapy and preventive measures for all pets in the household. Therapeutic options for the treatment of cheyletiellosis include selamectin topically every two weeks, fipronil once monthly, lime sulfur dips weekly for three to four weeks or oral ivermectin once weekly for three weeks.5-8 Prevention

BY KATHERINE DOERR, DVM, DACVDCONTRIBUTING AUTHOR

F E L I N E E C T O P A R A S I T I C D I S E A S E S :

TREATMENT AND PREVENTIVE MEASURES

10 Banfield Journal www.banfield.com/banfield-journal

is achieved with the use of topical fipronil or selamectin, applied monthly.

Sarcoptic scabiei and Notoedres cati Therapy for Sarcoptes scabiei var canis and Notoedres cati are similar in the cat. The most effective option is a 2-4 percent solution of lime sulfur in warm water applied once weekly for four to six weeks. Other options include selamectin monthly applied topically between the shoulder blades once monthly, and subcutaneous ivermectin at 0.2-0.3 mg/kg every two weeks.9,10 All pets in the household must be treated concurrently in order to prevent the spread of the mites. Prevention may be achieved by using selamectin topically once a month, or off-label topically every two weeks.11

Demodex spp. Choice of therapy for feline demodicosis depends upon the species of mite involved. The feline follicular mite, Demodex cati, can be very difficult to treat as there is usually an underlying disease resulting in the proliferation of mites. Reported underlying conditions include diabetes mellitus, feline immunodeficiency virus, feline leukemia virus, systemic lupus erythematosus, squamous cell carcinoma in situ or hypercortisolism.12-18

Demodex cati can be controlled by using 2-4 percent lime sulfur dips weekly. However, clients should be informed that a relapse is likely unless the primary disease is controlled.14 Demodex gatoi is highly contagious to other pets, so it is important that therapy is instituted on all in-contact animals. Therapy consists of weekly 2 percent lime sulfur dips for a minimum of six weeks or 0.2-0.3 mg/kg of oral ivermectin daily.19

INSECTSFelicola subrostratus Felicola subrostratus, the primary feline louse, is contagious to other in-contact pets. There are multiple treatment modalities for pediculosis such as topical fipronil, selamectin or imidacloprid, applied monthly.20,21 Currently, the best option for oral medication is oral ivermectin at 0.2 mg/kg daily. Prevention of lice is based upon ensuring proper cleanliness of the patient and its environment, such

as removing thick hair mats, cleaning the bedding and premises and removing affected grooming implements. The topical monthly therapies mentioned for pediculosis can also be utilized as preventive measures.22

Ctenocephalides felis felis Ctenocephalides felis felis is a common ectoparasite that can be quite difficult to manage and prevent unless all life cycle stages are removed from the environment. Choice of therapeutic measures depends upon the patient’s hypersensitivity to the parasite, the parasite load and the patient’s environment (indoor versus outdoor).22 For cats with flea bite hypersensitivity, it is important to begin with a medication that kills fleas quickly, in order to reduce exposure to flea salivary antigen. Nitenpyram, given orally once daily, kills adult fleas within 30 minutes.23 Spinosad has recently been approved for use in cats once monthly and also is adulticidal within 30 minutes to an hour.24 Many topical products contain an insect growth regulator (i.e., methoprene or pyriproxifen) that assists in preventing larvae from developing to the pupal stage, as well as preventing eggs from hatching. Prevention of flea infestation is just as important as treatment, since finding only a few fleas on a pet may indicate a larger subpopulation of earlier life stages in the environment. Utilizing adulticidal as well as larvicidal therapy is paramount for successful treatment and prevention of a flea infestation.

CONCLUSIONFeline ectoparasitic disease is eminently curable; thus, it is very important to rule out parasitic disease early in the diagnostic process with appropriate cytological samples or therapeutic trials. In order to have treatment success, the life cycle of the parasite should be kept in mind, so that all life stages are eliminated. It is also important to educate the client on the potential for zoonotic disease or the spread to other pets in the household. When keeping all of these factors in mind, diagnosis and treatment of ectoparasites can be very rewarding for all involved.

Summer 2014 11

Table 1: Therapeutic agents used for the treatment and/or prevention of parasites causing dermatologic disease in cats

Parasite Treatment Prevention Comments

Otodectes cynotis Topical otic preparations containing 0.01 percent ivermectin or 0.1 percent milbemycin oxime, applied once in each ear; selamectin, applied topically between the shoulder blades

Selamectin, applied topically between the shoulder blades once monthly

The mite is readily transmissible; keep healthy cats away from potential carriers

Cheyletiella blakei Selamectin topically every 2 weeks;fipronil once monthly; 2-4 percent solution of lime sulfur in water weekly for 3 to 4 weeks; oral ivermectin once weekly for 3 weeks

Topical fipronil or selamectin, applied monthly between the shoulder blades

Sarcoptes scabiei or Notoedres cati

2-4 percent solution of lime sulfur in warm water once weekly for 4 to 6 weeks; selamectin topically monthly; subcutaneous ivermectin at 0.2-0.3 mg/kg every 2 weeks

Selamectin topically once a month or every 2 weeks (off-label usage)

All pets in the household must be treated concurrently in order to prevent the spread of the mites

Demodex spp.D. cati 2-4 percent lime sulfur dips weekly Cat usually has an

underlying disease, which must be treated;relapse is likely unless the primary disease is controlled

D. gatoi 2 percent lime sulfur dips weekly in warm water for a minimum of 6 weeks; 0.2-0.3 mg/kg ivermectin PO daily

Highly contagious to other pets, so it is important that therapy is instituted on all in-contact animals

Felicola subrostratus Topical fipronil, selamectin or imidacloprid, applied monthly

Proper cleanliness of the patient and its environment: remove thick hair mats, clean bedding and premises, remove affected grooming implements; topical therapies as per treament

Ctenocephalides felis felis

Nitenpyram once daily PO for cats with flea bite hypersensitivity;spinosad once monthly PO

Topical flea preventives (e.g., fipronil, selamectin or imidacloprid);these are usually combined with an insect growth regulator (methoprene or pyriproxifen); thorough decontamination of the environment may be necessary

12 Banfield Journal www.banfield.com/banfield-journal

ABOUT THE AUTHORKatherine Doerr, DVM, DACVD, is a diplomate of the American College of Veterinary Dermatology. Her dermatology residency was completed at the University of California-Davis Veterinary Medical Teaching Hospital, following an internship at the Matthew J. Ryan Veterinary Hospital at the University of Pennsylvania. She has been published in Veterinary Dermatology and gives continuing education talks for the local veterinary community. Currently, she works at Pacific Veterinary Specialists in the Monterey Bay, Calif., area. In her free time, she runs distance events, rides mountain and road bikes, and surfs.

References 1. Sotiraki ST, Koutinas AF, Leontides LS, et al.

Factors affecting the frequency of ear canal and face infestation by Otodectes cynotis in the cat. Vet Parasitol. 2001;96:309-315.

2. Nunn-Brooks L, Michael R, Ravitz L, et al. Efficacy of a single dose of an otic ivermectin preparation or selamectin for the treatment of Otodectes cynotis infestation in naturally infected cats. J Fel Med Surg. 2011;13:622-624.

3. Davis WL, Arther RG, Settje TS. Clinical evaluation of the efficacy and safety of topically applied imidacloprid plus moxidectin against ear mites (Otodectes cynotis) in client-owned cats. Parasitol Res. 2007;101:S19-S24.

4. Vincenti P, Genchi C. Efficacy of fipronil (Frontline Spot on) in the treatment of ear mites (Otodectes cynotis) in dogs and cats. Proceedings of the 14th Congress ESVD. 1997:5-7.

5. Mueller RS, Bettenay SV. Efficacy of selamectin in the treatment of canine cheyletiellosis. Vet Rec. 2002;151:773.

6. Chailleux N, Paradis M. Efficacy of selamectin in the treatment of naturally acquired cheyletiellosis in cats. Can Vet J. 2002;43:767-770.

7. Bourdeau P, Lecanu JM. Treatment of multiple infestations with Otodectes cynotis, Cheyletiella yasguri, and Trichodectes canis with fipronil. Proc Br Vet Dermatol Study Group. Autumn 1999;35-36.

8. Curtis CF. Current trends in the treatment of Sarcoptes, Cheyletiella and Otodectes mite infestations in dogs and cats. Vet Dermatol. 2004;15:108-114.

9. Leone F. Canine notoedric mange: A case report. Vet Dermatol. 2007;18:127-129.

10. Itoh N, Muraoka N, Aoki M, et al. Treatment of Notoedres cati infestation in cats with selamectin. Vet Rec. 2004;154:409.

11. Paradis M. Ivermectin in small animal dermatology. Part II. Extra-label applications. Comp Cont Ed. 1998;20(4):459-469.

12. Chesney CJ. Demodicosis in the cat. J Small Anim Pract. 1989;30:689-695.

13. Nutting WB. Hair follicle mites (Demodex spp) of medical and veterinary concern. Cornell Vet. 1976;66:214-231.

14. Löwenstein C, Beck W, Bessmann K, et al. Feline demodicosis caused by concurrent infestation with Demodex cati and an unnamed species of mite. Vet Rec. 2005;157(10):290-292.

15. Guaguere E, Muller A, Degorce-Rubiales F. Feline demodicosis: a retrospective study of 12 cases. Vet Dermatol. 2004;15(Suppl 1):34.

16. Chalmers S, Schick RO, Jeffers J. Demodicosis in two cats seropositive for feline immunodeficiency virus. JAVMA. 1989;194(2):256-257.

17. Guaguère E, Olivry T, Delverdier-Poujade A, et al. Demodex cati infestation in association with feline cutaneous squamous cell carcinoma in situ: A report of five cases. Vet Dermatol. 1999;10:61-67.

18. White SD, Carpenter JL, Moore FM, et al. Generalized demodicosis associated with diabetes mellitus in two cats. JAVMA. 1987;191(4):448-450.

19. Morris DO, Beale KM. Feline demodicosis-A retrospective of 15 cases. Proc Annu Memb Meet Am Acad Vet Dermatol Am Coll Vet Dermatol. 1997;13:127-128.

20. Pollmeier M, Pengo G, Longo M, et al. Effective treatment and control of biting lice, Felicola subrostratus (Nitzsch in Burmeister, 1838), on cats using fipronil formulations. Vet Parasitol. 2004;121:157-165.

21. Shanks DJ, Gautier P, McTier TL, et al. Efficacy of selamectin against biting lice on dogs and cats. Vet Rec. 2003;152(8):234-237.

22. Miller W, Griffin C, Campbell K. Small Animal Dermatology. St. Louis, Mo. Saunders. 2013;320-324.

23. Cadiergues MC, Steffan J, Tinembart O, et al. Efficacy of an adulticide used alone or in combination with an insect growth regulator in simulated home environments. Am J Vet Res. 1999;609:1122-1125.

24. Robertson-Plouch C, Baker KA, Hozak RR, et al. Clinical field study of the safety and efficacy of spinosad chewable tablets for controlling fleas on dogs. Vet Ther. 2008;9(1):26-36.

Summer 2014 13

The Banfield Journal is getting a makeover!

Don’t miss out!We’ll alert you when new clinical articles and resources

are available at banfield.com/banfieldjournal. Just provide us your email address and we’ll keep you up to date!

Sign Up