ABSTRACT OF THE WEEK

Veterinary dermatology
Volume 25 | Issue 3 (June 2014)

An open, self-controlled study on the efficacy of topical indoxacarb for eliminating fleas and clinical signs of flea-allergy dermatitis in client-owned dogs in Queensland, Australia.

Vet Dermatol. June 2014;25(3):195 - e49.

Petr Fisara¹, Roger M Sargent², Michael Shipstone³, Andrew von Berky⁴, Janet von Berky⁵

¹ MSD Animal Health, 26 Artisan Road, Seven Hills, NSW, 2147, Australia.; ² MSD Animal Health, 26 Artisan Road, Seven Hills, NSW, 2147, Australia.; ³ Dermatology for Animals, 263 Appleby Road, Stafford Heights, Qld, 4053, Australia.; ⁴ von Berky Veterinary Services, 3 Hawthorne Street, Woody Point, Qld, 4019, Australia.; ⁵ von Berky Veterinary Services, 3 Hawthorne Street, Woody Point, Qld, 4019, Australia.

Abstract

BACKGROUND:Canine flea-allergy dermatitis (FAD), a hypersensitivity response to antigenic material in the saliva of feeding fleas, occurs worldwide and remains a common presentation in companion animal veterinary practice despite widespread availability of effective systemic and topical flea-control products.

HYPOTHESIS/OBJECTIVES:To evaluate the clinical response in dogs with FAD treated topically with indoxacarb, a novel oxadiazine insecticide.

ANIMALS:Twenty-five client-owned dogs in Queensland, Australia diagnosed with pre-existing FAD on the basis of clinical signs, flea-antigen intradermal and serological tests.

METHODS:An open-label, noncontrolled study, in which all dogs were treated with topical indoxacarb at 4 week intervals, three times over 12 weeks.

RESULTS:Twenty-four dogs completed the study. Complete resolution of clinical signs of FAD was observed in 21 cases (87.5%), with nearly complete resolution or marked improvement in the remaining three cases. Mean clinical scores (Canine Atopic Dermatitis Extent and Severity Index-03) were reduced by 93.3% at week 12. Mean owner-assessed pruritus scores were reduced by 88% by week 12. Mean flea counts reduced by 98.7 and 100% in weeks 8 and 12, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE:Topical indoxacarb treatment applied every 4 weeks for 12 weeks, without concomitant antipruritic or ectoparasiticide therapy, completely alleviated flea infestations in all dogs and associated clinical signs of FAD in a high proportion of this population of dogs in a challenging flea-infestation environment.

Companion Notes

Open-label, non-controlled study on the efficacy of topical indoxacarb for eliminating fleas and clinical signs of flea-allergy dermatitis in dogs in Queensland, Australia

- funded by Merck Animal Health, Summit, NJ, USA

Introduction on the treatment of flea-allergy dermatitis (FAD) in the dog

- very common skin disease in dogs

- results from a hypersensitivity response to antigens in saliva of feeding fleas

- these are injected intradermally

- Ctenocephalides felis is most common flea infesting dogs in the 3 areas

- USA

- Europe

- Australia

- indoxacarb (oxadiazine insecticide)

- reported to have significant insecticidal activity against adult C felis

- mechanism of action

- blockade of neuronal voltage-dependent sodium channels

- indoxacarb is metabolized by insect esterase enzymes

(after ingestion or contact by fleas)

- metabolized to a highly insecticidal form

- process referred to as `bioactivation’

- reported to have ovicidal activity

- reported to effective against flea larval stages in the host environment

Study design

- study population:

- 25 pet dogs in Queensland, Australia diagnosed with pre-existing FAD

- diagnosis of FAD based on the following:

- clinical signs

- flea-antigen intradermal and serological tests

- immediate- and delayed-type hypersensitivity reactions

- to intradermally injected flea antigen

(Greer Laboratories, Greer Veterinary, Lenoir, NC)

- wheal formation at flea-antigen injection site assessed

- 5-10 minutes post-injection (immediate reaction)

- or 24 hours post-injection (delayed reaction)

- compared with reactions to controls

- if no skin reactions then a serum sample tested

- commercial laboratory for flea-antibody (IgE) serology

(Allercept assay; Heska, Gribbles Veterinary

Pathology Laboratory, Clayton, Victoria,

Australia)

- 22 dogs had a positive immediate- or delayed-type wheal response

- 3 negative tests were serum positive for flea antibodies

- 24 dogs completed the study (one owner relocated)

- history & signalment (sex:M, 16 cases (5 intact))

- age range: 10 months to 12 years of age

- weight range: 3.2-41.6 kg

- procedure:

- study was conducted during the summer months in Queensland

- dogs kept at home and fed and exercised according to usual routine

- indoxacarb, at 4 week intervals, 3 times over 12 weeks

(Activyl^®; Merck/MSD Animal Health, Summit, NJ, USA)

- assessment methods

- dermatologist assessment using CADESI-03

(Canine Atopic Dermatitis Extent and Severity Index)

- scores were converted into 4 arbitrary categories

- ‘in remission or insignificant’

- assigned with score intervals of 0-15

- ‘mild’ assigned with score intervals of 16-59

- ‘moderate’ assigned with score intervals of 60-119

- ‘severe’ based on score intervals of 120+

- CADESI scoring system only validated for atopic dermatitis

- owner-assessed pruritus severity score from 0-100

(Pruritus Visual Analog Scale (PVAS))

- flea counts carried out at home

- 6 representative skin areas were searched for fleas for 1 minute

- if no fleas found then entire body searched for 2 minutes

Results

- complete resolution of clinical signs of FAD, 21 cases

- nearly complete resolution or marked improvement, 3 cases

- mean Canine Atopic Dermatitis Extent and Severity Index-03) scores

- reduced by 93.3% at week 12

- reduced by 59% at week 4

- reduced by 85% at week 8

- mean CADESI scores

- pretreatment: 90.1

- 4 weeks: 36.9

- 8 weeks: 13.5

- 12 weeks: 6.0

- mean owner-assessed pruritus scores reduced by 88% by week 12

- mean flea counts

- reduced by 98.7% by week 8

- reduced by 100% by week 12

- mean flea counts

- pretreatment: 18.0 with a range of 0-124

- 4 weeks: 1.1 with a range of 0-6

- 8 weeks: 0.3 with a range of 0-3

- 12 weeks: 0.0

“All dogs enrolled in the study were considered to have clinical signs consistent with FAD; however, three of these 25 dogs were negative on skin testing with flea allergen and six of the dogs were flea free on pretreatment flea counts. Clinicians suspecting FAD based on clinical signs will probably continue to recommend effective flea treatment as a reliable method for subsequent evaluation of the aetiology of these signs.”

Article Tools:

Medline

Email to me

Archives Highlights:

Bone Marrow Aspiration in Dogs: Indications and a Step-by-Step Tutorial
In dogs, bone marrow aspirates are often collected from the proximal humerus or ilium. A special 14- to 18-gauge needle with stylet is placed into the bone marrow cavity, and cells are subsequently aspirated. These needles are designed to penetrate cortical bone without becoming obstructed. Other sites in dogs include the sternum, ribs, and proximal femur. Aspiration from the pelvis and femur is challenging, if the region contains abundant adipose tissue.

Difficulty walking and trembling in a 10-year-old female Akita Inu.
The overall prognosis in dogs with orthostatic tremors is considered to be good, as the disease is benign and slowly progressive.

Intrathecal mepivacaine after general anesthesia is an effective method of equine euthanasia when compared to intravenous pentobarbital.
Previous publications have shown that the risk of scavenger intoxication through consumption of the carcass is low with an intrathecal lidocaine method. In horses euthanized with intravenous pentobarbital, sodium pentobarbital residues were found in compost pile samples up to 367 days after euthanasia with no decrease in concentration, despite complete degradation of soft tissues.

High-pressure injection of paint into the hand: A small injury with serious consequences.
High-pressure injection injury to the hand is a serious lesion threatening the limb. Several injected materials are involved, and paint is known to have the most serious consequences, with a high amputation rate. Early diagnosis and prompt treatment are two important prognostic factors for a better outcome.

Urinary Tract Trauma in Cats: Stabilisation, Diagnosis and Management.
This review summarises the current knowledge available from a number of original articles and textbook chapters in the literature that cover all aspects of feline urinary tract trauma, and is supported by the authors' own clinical experience.