ABSTRACT Feline demodicosis caused by Demodex cati is a rare parasitic disease, characterized by local or generalized dermatitis and less commonly by otitis. A feline, male, castrated, mixed breed, 11 years old, presented progressive cervical pruritus with alopecia in the caudolateral region of the right ear and mild erythema, abrasions, brownish ceruminous secretion and otopodal reflex. He had a history of feline immunodeficiency virus (FIV) infection and feline gingivitis stomatitis complex (GSC), in addition to continuous use of prednisolone. In the parasitological examination of the cerumen, different stages of Demodex sp. were found. Genetic sequencing revealed 99.33% homology for D. cati. Therapy with imidacloprid and moxidectin in spot-on formulation, in two doses at 30-day intervals, promoted remission of clinical signs and elimination of the mite.

The purpose of the research is to study the epizootic situation of ectoparasitosis of cats in the Moscow metropolis, taking into account the season and the age of the animals.Materials and methods. The study of the seasonal and age dynamics of infection of cats with ectoparasites in the Moscow metropolis was carried out on the basis of the All-Russian Scientific Research Institute of Infectious Diseases (VNIIP), a branch of the Federal State Budgetary Institution FSC VIEV RAS, as well as the veterinary clinic GLOBALVET CLINIC LLC (Moscow) in 2020–2022. We examined 85 cats in different seasons. When examining the animals, attention was paid to damage to the skin and hair. At the same time, the gender, age, condition of the skin and hair of the animals were taken into account; the ears were examined and the hair was combed using a magnifying glass; Microscopic examination of the ear contents, as well as scrapings of the superficial and deep layers of the skin. The number of ectoparasites was determined according to the method of M. V. Arisov, I. A. Arkhipov (2018). The results obtained were processed statistically using Microsoft Excel.Results and discussion. Infection of cats with Demodex cati was maximum in Spring and Summer (5.9%), and decreased to 3.5% in Autumn and Winter. Ixodes ricinus mites were found on the skin and hair of cats (15%) only in the warm season. We noted an increase in the infection of cats with Otodectes cynotis and Notoedres cati in Spring and Summer. The seasonal dynamics of infection of cats by insects of different species differed. Fleas were found in 4.7% of cats in Winter, and in 8.5 and 10.6% of cats in Spring and Summer, respectively. The infection of cats with lice eaters was low.

The Demodecidae are skin and tissue parasites of mammals with high host, topical, and topographic specificity. They may cause a demodecosis, typically observed in pets and humans. Numerous mammal species have been found to have several, specific demodecids, which inhabit different microhabitats. Thus far, two species have been known from the domestic cat, namely Demodex cati Megnin, 1877 (Acariformes: Demodecidae) and D. gatoi Desch and Stewart, 1999; however, there have been indications for the presence of other demodecid mites in this host. Presently, two other species are described, D. murilegi sp. nov. associated primarily with the skin from the area of lips and nose, and D. obliquus sp. nov. associated with the skin of the lower part of the limb. They exhibit morphological discreteness in terms of qualitative traits significant for Demodecidae taxonomy. Demodex murilegi sp. nov. is larger than both known species, and D. obliquus sp. nov. is intermediate in length between them. It is likely that infection with different Demodex species may result in variable symptoms and courses of demodecosis; however, a correct identification of the species causing the parasitosis is needed to confirm this. Thus, the present study compares the taxonomic traits of four cat demodecid mites.

Demodicosis is an uncommon disease in the clinical-dermatological routine of felines. It can be caused by the Demodex gatoi or Demodex cati, and a new, as yet unnamed species has been reported. Numerous forms of diagnosis and therapeutic protocols have been reported for canine demodicosis for years. However, there are few current studies on the subject in felines. Therefore, the present work aims to carry out a literature review on this skin disease, with a description of its etiology, epidemiology, clinical signs, diagnosis and current forms of treatment, as feline demodicosis still has a therapeutic and diagnostic difficulty because it is a rare and low-incidence disease. Future studies are still needed to reach a better understand of the disease and to define a more concise therapeutic protocol, including standardization of doses and frequency of administration.

This case report describes the successful use of fluralaner in treating demodicosis caused by Demodex cati in a cat. A 4.2 kg 10 – year – old spayed female Siamese short – haired cat was presented with a 5 – month history of severe dermatitis. The cat had been treated at previous animal hospitals with a variety of drugs such as antimicrobials, glucocorticoids and ectoparasiticides on separate occasions but the clinical signs remained severe. Microscopic examination of skin samples revealed the presence of D. cati. The cat was treated with a single dose of spot – on formulation of fluralaner at the minimum dosage of 25 mg/kg. The cat’s skin lesions decreased by day 21 and the skin lesions were resolved by day 56. There were no clinical abnormalities in a cat throughout the treatment.

Case summaryA 10-year-old spayed female Russian Blue cat was presented with a 3-month history of excessive otic discharge and scratching, only involving the right ear. Other than a moderate amount of ceruminous exudate present within the right ear on video-otoscopic examination, there were no other cutaneous abnormalities. The cat was deemed to be otherwise in good health based on physical examination and several laboratory profiles. A diagnosis of otodemodicosis was determined due to the presence of a large number of Demodex cati mites retrieved from cerumen. Treatment consisted only of monthly topical application of sarolaner/selamectin to the nape of the neck with a marked reduction in mite counts and otic pruritus after a single dose. Complete resolution was achieved after a total of four doses.Relevance and novel informationThis is the first report to describe the resolution of mite infestation owing to D cati after treatment with a sarolaner-containing spot-on product. In addition, to the best of the author’s knowledge, this is the first report of any isoxazoline product used in the successful treatment of demodicosis affecting the ear canal. In general, there is a lack of reports describing safe and effective treatments for feline otodemodicosis. Topically applied sarolaner/selamectin resulted in resolution of mites while avoiding any potential ototoxic events from medications applied directly into the ear, and provided a treatment that was easier to apply than oral or injectable macrocyclic lactones.

A case of co-infection due to Demodex cati and feline immunodeficiency virus in a cat is described. A 5 year-old neutered male cat was presented to the Small Animal Clinic at the Faculty of Veterinary Medicine, Trakia University with lethargy, diarrhoea, pyrexia, anorexia, adipsia, skin lesions, intense itching and alopecia. Parasitological, mycological and serological examinations were carried out. Adult D. cati mites and antibodies against FIV were detected. A proper therapy with an endectocide, antibiotic and antihistamine drug was prescribed. The improvement of the general condition was observed after a month of treatment. Later, the disease recurred twice and the animal was humanely euthanased for medical reasons and at the owner’s request.

Background: Feline demodicosis is considered an uncommon dermatopathy in cats that is mainly caused by the mite Demodex cati, but in few cases D. gatoi may be involved. Although the clinical aspects and pathogeny of feline demodicosis are not completely understood, its clinical expression is believed to be associated with the presence of primary immunosuppressive agents. Thus, the aim of this study is to report the diagnosis and treatment of an infested cat by D. cati, associated with mixed intestinal parasitic infection. Case: An approximately 1-year-old male short hair cat which was grown in a rural area was presented at the Veterinary Hospital of the Federal University of Pampa (Unipampa) in Uruguaiana, Rio Grande do Sul. The cat had alopecia, itching, excoriations on neck and head, and softened feces as clinical signs. Performed skin scrapings revealed eggs, larvae and adult forms of D. cati. In order to fnd possible immunosuppressive agents, exams for detection of feline immunodefciency virus (FIV) and feline leukemia virus (FeLV) were also performed. They revealed, however, negative results for FIV and FeLV infections. Moreover, coproparasitologic analysis revealed the presence of the intestinal parasites Trichuris sp., Ancylostoma sp., and Spirometra mansonoides. Thus, it was decided to proceed the treatment utilizing 0.2 mg/kg of moxidectin subcutaneously every four days and weekly shower with antiseptic shampoo containing 0.15% triclosan. In addition, it was prescribed oral doses of febendazol (50 mg/kg/day) for four days. After 20 days of treatment, the skin lesions had decreased signifcantly and the skin scrapings were negative for D. cati. In this way, the showers with 0.15% triclosan was suspended. Nevertheless, the treatment with moxidectin was maintained for more fours weeks until totalclinical healing was achieved with hair growth and absence of skin lesions. Furthermore, after the treatment with febendazol the animal feces had reached a normal consistency and new coproparasitologic analysis revealed negative results for the presence of intestinal parasites. Discussion: The diagnosis of Demodex cati was based on clinical history, physical examination (alopecia, excoriation in the head and neck) and microscopic visualization of the mite in skin scrapings. The treatment used with moxidectin, acaricidal quite safe and effective, widely used in treatment of canine demodicosis, but no reports about the use in cats. The mite D. cati is considered normal resident of cat’s skin, and the pathogenesis of demodicosis is still unknown. It is known that the playback exacerbated mite can present with skin lesions is commonly associated with immunosuppression states. The presence of three different intestinal parasites (Spirometra mansonoides, Trichuris sp., and Ancylostoma sp.) might have been essential for an immunosuppressive status of the cat and clinical development of demodicosis. Thus, this report supports the hypothesis that a primary immunosuppressive agent is necessary for clinical development of feline demodicosis. Nevertheless, further researches are necessary in order to determine the prevalence of feline demodicosis and correlate the presence of cestodes and development of this disease. In addition, this report highlights the therapeutic success utilizing na association of moxidectin and topic treatment with the treatment of possible immunosuppressive agents.Keywords: dermatopathy, imunossuppression, cat, therapy

Feline demodicosis is a parasitary dermatophathy that affects cats at a much lower frequency than the one observed in dogs. There are three species identified in felines: Demodex gatoi, Demodex cati and a third species unofficially called Demodex felis. Clinical signs are widely variable and seem to differ according to the individual species of mite involved. Diagnostic depends on mite identification upon microscopic examination of skin scrapings; Demodex gatoi may also be found in feces. The present article describes a case of localized feline demodicosis that occurred in the city of Foz do Iguaçu, Parana. The microscopic mite morphology and the clinical signs resembled those caused by Demodex cati. Despite being rare, it is important to include this disease in the differential diagnosis of feline skin diseases.

Demodex cati and Demodex gatoi are considered the two Demodex species of cats. However, several reports have identified Demodex mites morphologically different from these two species. The differentiation of Demodex mites is usually based on morphology, but within the same species different morphologies can occur. DNA amplification/sequencing has been used effectively to identify and differentiate Demodex mites in humans, dogs and cats. The aim was to develop a PCR technique to identify feline Demodex mites and use this technique to investigate the frequency of Demodex in cats. Demodex cati, D. gatoi and Demodex mites classified morphologically as the third unnamed feline species were obtained. Hair samples were taken from 74 cats. DNA was extracted; a 330 bp fragment of the 16S rDNA was amplified and sequenced. The sequences of D. cati and D. gatoi shared >98% identity with those published on GenBank. The sequence of the third unnamed species showed 98% identity with a recently published feline Demodex sequence and only 75.2 and 70.9% identity with D. gatoi and D. cati sequences, respectively. Demodex DNA was detected in 19 of 74 cats tested; 11 DNA sequences corresponded to Demodex canis, five to Demodex folliculorum, three to D. cati and two to Demodex brevis. Three Demodex species can be found in cats, because the third unnamed Demodex species is likely to be a distinct species. Apart from D. cati and D. gatoi, DNA from D. canis, D. folliculorum and D. brevis was found on feline skin.

Two feline Demodex mite species have been described as causative agents of feline demodicosis, until recently a third species was detected. We provide an updated analysis on the phylogenetic relationship of Demodex mites. In addition, we present the first qPCR assay for the detection and differentiation of all three feline mite species in a single reaction. Specimen of Demodex cati, Demodex gatoi, and the recently discovered third species were collected from skin scrapings and fecal flotation for DNA extraction, conventional PCR, sequencing, and alignment. A total of 24 sequences of the partial 16S rRNA gene were used to estimate the evolutionary divergence in a p-distance model and a maximum likelihood phylogenetic tree. For the qPCR assay, new primers and fluorescent probes for the simultaneous detection of all three feline Demodex mites were designed. A consensus fragment of 351 bp was phylogenetically analyzed. The third species sequence of our study shares 98.6 % similarity to the available sequence in GenBank®. It is most similar to D. gatoi (82.41 %) and most distant to the canine Demodex injai (78.28 %). In contrast, D. gatoi is most similar to human Demodex brevis (87.01 %). The multiplex qPCR detected and discriminated the three different mite species in one reaction. The detection limit is ≤1.4 ng of mite DNA. The three feline Demodex species have distinct genotypes and did not cluster in one genetic clade. The species differentiation and assessment of evolutionary relationships will ultimately support correct diagnostics and treatment approaches.

Feline demodicosis due to Demodex cati is a rare skin disease often associated with concurrent disease and generalized immunosuppression. Local immunosuppression due to the application of topical immunomodulatory drugs, such as glucocorticoids and tacrolimus, or by tumour cells has been suggested as a potential trigger for development of localized demodicosis in humans and animals. The goal was to describe two cats with asthma that developed localized demodicosis on the muzzle as a result of chronic therapy with a glucocorticoid administered via dispensing inhaler mask. In both cats, the muzzle area exposed to the fluticasone-dispensing chamber exhibited patchy alopecia, mild erythema, crusting and scaling. Deep skin scraping revealed D. cati. Discontinuation or reduction of fluticasone and administration of milbemycin resulted in resolution of clinical signs within 2months in both cats. A negative skin scrape was obtained after 7months of milbemycin in one of the cats. Demodicosis should be considered as a possible differential diagnosis in cats with primary alopecia or other skin lesions on the face exposed to inhalant glucocorticoids. Minimization of contact between the inhalant glucocorticoid and the skin can be achieved by wiping residual powder from the face and by keeping the mask tightly pressed to the skin to avoid contact with the surrounding area.

Feline otitis externa is a dermatological disorder that has not been evaluated much in stray cats. One hundred and eighty-seven stray cats were randomly selected during a trap-neuter-release programme to investigate the prevalence of otitis externa in stray cat colonies in northern Italy. Swabs for cytological examination were obtained from the external ear canal of each cat. A direct otoscopic assessment of the external ear canal was made in 86/187 cats. Cytological evidence of otitis externa was present in 55.1% of cats. The influence on otitis of age, gender, habitat and season of sampling was tested, but no risk factors were found. Otodectes cynotis (as a sole agent or in combination) was the primary cause of otitis in 53.3% of cats. Cocci and rods, either alone or in combination with other agents, were perpetuating factors in 71.8% and 29.1% of cats, respectively. Pregnancy status was a risk factor for otitis caused by coccal infections. Malassezia species, alone or in combination, was the perpetuating factor in 50.5% of cats with otitis. Urban habitat and winter season were risk factors for otitis associated with Malassezia species. Demodex cati was identified as an incidental finding in two cats. There was good agreement between otoscopy and cytology with regard to the diagnosis of otitis externa. The results of this study show a high prevalence of otitis externa in stray colony cats and provide information on causal factors for feline otitis externa.

Feline demodicosis is a rare parasitic condition caused by three different species of mites (Demodex cati, Demodex gatoi, and an unnamed species). D. gatoi inhabits the superficial skin layer (stratum corneum) and is easily transmitted between individual cats. A 2-year-old female spayed Cornish Rex was presented with alopecia and pruritus. The dermatological examination revealed bilateral alopecia and excoriations on trunk, limbs, and belly. The second cat in the household, a 3-year-old female spayed Thai, showed no clinical signs. Superficial and deep skin scrapings were performed and cellophane tapes applied, and living D. gatoi mites could be detected in both cats. Oral ivermectin (0.25 mg/kg every other day) was subscribed. Feces were collected from both cats and fecal flotation with sugar and zinc solutions performed. When compared to skin scrapings and cellophane tapes, D. gatoi was detected more frequently and in higher numbers in fecal samples. Our findings suggest that D. gatoi can be efficiently diagnosed with coproscopy, particularly in asymptomatic carrier animals. DNA was extracted from the flotation liquid, and a PCR protocol for the species verification was designed. A fragment targeting a 325-bp DNA fragment of the D. gatoi mitochondrial 16S rDNA gene was amplified with a 100% similarity to the D. gatoi entry in GenBank® (GI 421920216). We report the first finding of D. gatoi in Austria and propose fecal flotation as a valuable tool for mite detection. Fecal flotation liquid is suitable for DNA extraction and PCR-based species verification of D. gatoi.

Feline demodicosis is caused by infestation with Demodex cati and/or Demodex gatoi. These two mites have distinctive morphological appearances. To describe five observations of a morphologically distinct feline Demodex mite in 10 cats. All cats were in or adopted from an animal shelter. A mite with blunted ends longer than D. gatoi but shorter than D. cati was observed in one or multiple cats from animal shelters. Mean mite size was 139 ± 4.5 μm (n = 41 mites). Similar features among the cases included a history of recent recovery or presence of concurrent illness at the time of diagnosis. Pruritus was variable. Hairs were easily epilated in large amounts, and mites were found on either skin scrapings or hair trichograms; mites were most commonly found on the proximal third of hairs examined via trichogram. Reports of this mite are uncommon but when present tend to be in cats with concurrent illnesses. Awareness of this mite morphology will hopefully provide other investigators with specimens for molecular testing to determine whether this is a third species or a variant of D. gatoi or D. cati.

Demodex gatoi causes a pruritic dermatitis in cats. Diagnosis requires the demonstration of mites using superficial skin scrapings or faecal flotation, which can be insensitive. The goal of this study was to develop a molecular method to diagnose D. gatoi infection in cats and distinguish these mites from Demodex cati. Fifty-three shelter cats, 11 cats from a closed research colony and 12 privately owned cats were used. Demodex gatoi and D. cati were obtained from scrapings of cat skin. The 16S rRNA DNA was amplified by PCR, sequenced and compared with available Demodex sequences. Hair and skin samples were also collected for microscopic examination and DNA isolation. DNA sequences were obtained from D. gatoi and D. cati. qPCR with D. gatoi specific primers and probe amplified DNA isolated from D. gatoi and not D. cati. Conversely, D. cati qPCR primers and probe amplified D. cati DNA and not D. gatoi. Five of the shelter cats were positive for D. gatoi. Two of these cats were pruritic, and the other three were in contact with these cats. Only one cat was positive for D. gatoi on skin scraping but was negative for D. gatoi or D. cati DNA. Results from this study show D. gatoi and D. cati to be distinct species. A novel qPCR test for the identification and differentiation of D. gatoi and D. cati was developed. Once optimized, this test could provide a valuable technique for the diagnosis of D. gatoi infection.

An 8-year-old, neutered male, domestic shorthair cat housed at the North Carolina State University, College of Veterinary Medicine, Laboratory Animal Research facility as part of a research colony was examined because of mulifocal skin lesions. The lesions consisted of patchy alopecia with mild crusting of the periauricular region, neck, and dorsum; periauricular excoriations; marked dorsal seborrhea and scaling; and generalized erythematous papules. A moderate amount of ceruminous exudate was present in both ear canals. Results of testing for feline immunodeficiency virus (FIV) were positive. An ear swab specimen and superficial and deep skin scrapings were obtained, mounted with oil on glass slides, and coverslipped for microscopic examination. Two populations of mites were observed: a large population of slender, long (approximately 200 microm), adult mites with long, tapering abdomens that comprised two-thirds of the total body length; and a smaller population of more translucent and shorter mites (approximately 100 microm) with wide, blunt abdomens that had prominent transverse ridges. The interpretation was demodicosis, with Demodex cati and D gatoi co-infection. Histologic sections of biopsies from skin lesions on the neck, dorsum, and periauricular area contained a mild perivascular and perifollicular inflammatory infiltrate composed predominantly of histiocytes, lymphocytes, and plasma cells. Diffusely within the follicular lumina and occasionally within the superficial keratin, a myriad of Demodex organisms were observed. Intrafollicular mites were compatible in appearance with D cati whereas those in the corneal layer were suggestive of D gatoi. Demodicosis is an uncommon disease of cats, and rare cases of dual infection have been documented, occasionally in FIV-infected cats. The dual infection emphasizes the importance of doing both superficial and deep skin scrapings and of recognizing the unique microscopic features of different Demodex mites.

Feline demodicosis is rarely reported compared to canine demodicosis. The objective of this report was to describe a retrospective study of 12 cases of feline demodicosis. Neither sex nor breed predisposition were observed. The age of diagnosis was between 5 months and 13 years. Demodex cati was identified in nine cases and Demodex gatoi in three cases. Cutaneous lesions were localized in 10 cases, generalized in two cases, and present on the face (8 cases), neck (5), shoulders (1), trunk (2) and limbs (1). Pruritus was mild in four cats and moderate in two cats. Dermatological lesions were characterized by alopecia (10 cases), erythema (7), scaling (4), erosions (4), ulcers (2), crusts (2), comedones (2), seborrhea oleosa (2), papules (1), pustules (1) and hyperpigmentation (1). Ceruminous otitis was noted in two cats. Pyoderma was noted in four cases. An underlying disease was identified in eight cats: FeLV infection (two cats), FIV infection (two cats), FeLV/FIV infections (one cat), diabetes mellitus (one cat), iatrogenic Cushing's syndrome (one cat), and diabetes mellitus associated with iatrogenic Cushing's syndrome (one cat). In two cats, an infestation by Demodex cati was identified at lesional sites of multicentric squamous cell carcinoma in situ. Different drugs were used in nine cases: crotamiton (two cases), amitraz (six cases), milbemycin oxime (one case). Therapeutic results were variable and related to the underlying disease. Funding: Self‐funded.

Opportunistic dermatoses can occur in case of immunosuppressive diseases. The first case was a 12‐year‐old domestic short‐haired cat suffering from diabetes with a phaeohyphomycosis due to Scytalidium spp.associated with cutaneous hemangiosarcoma. A painless and ulcerated nodule was observed on a digit with fistulous tracts over the metatarsal joint. Histopathological examination of the nodule revealed a hemangiosarcoma in which brownish fungal colonies were found. Itraconazole (5 mg/kg twice daily), then amputation, allowed 12 months of survival (pulmonary metastases). The second case concerned a 13‐year‐old Siamese cat with cheyletiellosisassociated with spontaneous Cushing's disease and diabetes mellitus. This cat exhibited scales and miliary dermatitis on the trunk associated with polyuria, polydipsia and a pot‐belly. Acetate tape impression showed Cheyletiella blakei mites and eggs. Blood analysis revealed diabetes mellitus and spontaneous hyperadrenocorticism. The owner refused treatment. The third case was a 14‐year‐old domestic short‐haired cat with generalized demodicosis associated with iatrogenic Cushing's disease and diabetes mellitus. Long‐acting glucocorticoids had been used for treatment of plasma cell stomatitis for 5 years. This cat exhibited erythema, scales, self‐induced alopecia, thin skin and moderate pruritus associated with polyuria and polydipsia. Cutaneous lesions principally developed on the abdomen and flanks. Skin scrapings and trichogram showed numerous Demodex cati mites. Routine blood work demonstrated diabetes mellitus and iatrogenic Cushing's disease. Treatment was based on insulin therapy, milbemycin oxime (1 mg/kg once daily) and chlorambucil (0.2 mg/kg once daily). The demodicosis was cured after 4 months, but the cat died of cutaneous and ocular herpesvirus infection 10 months later. Funding: Self‐funded.

Factors affecting the frequency of ear canal and face infestation by Otodectes cynotis in the cat