Small<i>Demodex</i>Populations Colonize Most Parts of the Skin of Healthy Dogs

Ravera, Iván; Altet, Laura; Francino, Olga; Sánchez, Armand; Roldán, Wendy; Villanueva, Sandra; Bardagí, Mar; Ferrer, L.

doi:10.1002/9781118644317.ch23

Cited by 8 publications

(18 citation statements)

References 22 publications

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“…17 Other studies using RT-PCR for Demodex detected positive results in 18% of dogs using five sample sites in a larger cohort of healthy dogs. 18 Direct proportionality between the number of positive dogs and the number of sampled sites was demonstrated clearly, as positive results increased to 100% with an increase in the number of sampled sites to 20. 18 A study in humans showed that although only 14% of individuals were positive on direct microscopic observation of samples, up to 100% of sampled individuals were positive with PCR.…”

Section: Conflicts Of Interestmentioning

confidence: 92%

“…18 Direct proportionality between the number of positive dogs and the number of sampled sites was demonstrated clearly, as positive results increased to 100% with an increase in the number of sampled sites to 20. 18 A study in humans showed that although only 14% of individuals were positive on direct microscopic observation of samples, up to 100% of sampled individuals were positive with PCR. 19 In humans, Demodex mites are localized almost exclusively to the face; the sampling and detection is easier than in dogs, where mites seem to be distributed all over the skin surface.…”

Section: Conflicts Of Interestmentioning

confidence: 92%

“…19 In humans, Demodex mites are localized almost exclusively to the face; the sampling and detection is easier than in dogs, where mites seem to be distributed all over the skin surface. 18 Other studies looking at Demodex prevalence in rosacea patients using different techniques have detected mites up to 100% of the time. [20][21][22][23] The objective of this study was to investigate if healthy dogs treated with the isoxazolines fluralaner (Bravecto â , Merck Animal Health; Madison, NJ, USA) and afoxolaner (NexGard â , Merial; Duluth, GA, USA) at the labelled dose for flea and tick prevention maintain a normal population of Demodex mites as part of their cutaneous microbiota.…”

Section: Conflicts Of Interestmentioning

confidence: 99%

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Afoxolaner and fluralaner treatment do not impact on cutaneous Demodex populations of healthy dogs

Zewe

Altet

Lam

et al. 2017

Veterinary Dermatology

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Section: Conflicts Of Interestmentioning

confidence: 92%

Section: Conflicts Of Interestmentioning

confidence: 92%

Section: Conflicts Of Interestmentioning

confidence: 99%

See 1 more Smart Citation

Afoxolaner and fluralaner treatment do not impact on cutaneous Demodex populations of healthy dogs

Zewe

Altet

Lam

et al. 2017

Veterinary Dermatology

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“…The expression of juvenile-onset disease may be linked to the gradual expansion of mite populations (Forton 2011, Ravera et al 2013 following mite transmission in the first days of life (Greve & Gaafar 1966). The genetic, immunological, endocrine or other factors that lead to higher than expected populations of mites associated with skin lesions, focally or more widespread, are poorly understood (Ferrer et al 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Canine demodicosis is commonly classified by either the age at onset (juvenile versus adult) and/or the extent of the disease (localised versus generalised) to assist with prognostic advice and to guide diagnostic and management approaches . Given that very low numbers of D. canis inhabit haired skin of dogs without skin disease (Ravera et al 2013), the question arises as to why some of these dogs develop skin lesions from which large numbers of mites can be recovered. In some affected dogs, lesions with abnormally high numbers of mites are few and transient (mild localised disease), while others show large areas and/or multiple sites affected by lesions that do not resolve without treatment (generalised disease) (Scott et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Juvenile‐onset and adult‐onset demodicosis in dogs in the UK: prevalence and breed associations

O'Neill

Turgoose

Church

et al. 2019

J of Small Animal Practice

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Objectives To explore epidemiological features of demodicosis relevant to UK veterinary general practitioners. Breed risk factors were proposed as distinct between juvenile‐onset and adult‐onset disease. Materials and Methods The study used anonymised clinical data on dogs under primary veterinary care at practices enrolled in the UK VetCompass Programme. Case inclusion required recording of a final demodicosis diagnosis for a dermatological condition that was present during the 2013 study period. Risk factor analysis used multivariable logistic regression modelling. Results In dogs aged <2 years (juvenile‐onset), the 1‐year period prevalence was 0.48% (95% confidence interval: 0.45 to 0.52). Compared with crossbred dogs, seven breeds showed increased odds of diagnosis with demodex: British bulldog, Staffordshire bull terrier, Chinese shar‐pei, dogue de Bordeaux, pug, French bulldog and boxer. Additionally, six breeds showed reduced odds of juvenile demodicosis: Lhasa apso, bichon frise, Labrador retriever, German shepherd dog, shih‐tzu and Chihuahua. In dogs aged >4 years (adult‐onset), the 1‐year period prevalence was 0.05% (95% confidence interval: 0.0.04 to 0.06). Six breeds showed increased odds of demodicosis compared with crossbred dogs: Chinese shar‐pei, shih‐tzu, West Highland white terrier, pug, boxer and Border terrier. Clinical Significance Juvenile‐onset demodicosis is much more common (about 10 times higher) than the adult‐onset form. Knowledge of the predisposed breeds for these two presentations can assist with diagnosis and support the concept of distinct aetiopathogenetic phenotypes.

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Immunology and pathogenesis of canine demodicosis

Ferrer

Ravera

Silbermayr

2014

Veterinary Dermatology

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Demodex mites colonized the hair follicles and sebaceous glands of mammals millions of years ago and have remained relatively unchanged in this protected ecologic niche since then. The host immune system detects and tolerates their presence. Toll-like receptor-2 of keratinocytes has been demonstrated to recognize mite chitin and to elicit an innate immune response. The subsequent acquired immune response is poorly understood at present, but there is experimental and clinical evidence that this is the main mechanism in the control of mite proliferation. A transgenic mouse model (STAT(-/-) /CD28(-/-) ) has demonstrated that the immune response is complex, probably involving both cellular and humoral mechanisms and requiring the role of co-stimulatory molecules (CD28). It is known that a genetic predisposition for developing canine juvenile generalized demodicosis exists; however, the primary defect leading to the disease remains unknown. Once the mite proliferation is advanced, dogs show a phenotype that is similar to the T-cell exhaustion characterized by low interleukin-2 production and high interleukin-10 and transforming growth factor-β production by lymphocytes, as described in other viral and parasitic diseases. Acaricidal treatment (macrocyclic lactones) decreases the antigenic load and reverses T-cell exhaustion, leading to a clinical cure. Although in recent years there have been significant advances in the management and understanding of this important and complex canine disease, more research in areas such as the aetiology of the genetic predisposition and the immune control of the mite populations is clearly needed.

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SmallDemodexPopulations Colonize Most Parts of the Skin of Healthy Dogs

Cited by 8 publications

References 22 publications

Afoxolaner and fluralaner treatment do not impact on cutaneous Demodex populations of healthy dogs

Afoxolaner and fluralaner treatment do not impact on cutaneous Demodex populations of healthy dogs

Juvenile‐onset and adult‐onset demodicosis in dogs in the UK: prevalence and breed associations

Immunology and pathogenesis of canine demodicosis

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