Prevalence of middle ear effusion in French bulldogs without clinical signs of otic disease: A retrospective study of magnetic resonance imaging (2017-2022).

BACKGROUND: Canine middle ear effusion (MEE) is usually asymptomatic, being an incidental finding when computed tomography or magnetic resonance imaging (MRI) of the head is performed for other reasons unrelated to otic disease. The clinical relevance of the presence of material in the tympanic bulla (TB) remains uncertain, and more detail about its prevalence and appearance in MRI are required. OBJECTIVE: To assess the prevalence of presence of material within the TB of French bulldogs (FB) with no clinical signs suggestive of otitis (externa, media or interna) that underwent high-field MRI for other medical reasons. ANIMALS: Two hundred fifty-two TB of 126 FB were included in this study. MATERIALS AND METHODS: Nonexperimental retrospective study in which MRI images were evaluated by a board-certified veterinary radiologist. RESULTS: Fifty-eight per cent of the dogs had material in the TB lumen (46% of the TB) and 59% were bilaterally affected. The signal intensity of this material related to the grey matter was variable on T1w and mainly hyperintense on T2w sequences. CONCLUSION AND CLINICAL RELEVANCE: FB are predisposed to MEE. This is important when assessing imaging studies of TB of FB with chronic otitis externa, as high percentage of cases may have concurrent MEE. MRI findings in FB with MEE are characterised by a hyperintense signal to the grey matter on T2w in most cases and variable on T1w sequences.

Feline leishmaniosis: diagnosis, treatment and outcome in 16 cats.

OBJECTIVES: Leishmaniosis is a vector-borne disease and in European countries is caused by Leishmania infantum. Cats are considered secondary reservoirs of the infection in endemic areas. The objective of this retrospective study is to describe the clinical findings, diagnosis, treatment and outcome of feline leishmaniosis (FeL) in 16 cats in Spain. METHODS: Medical records of cats diagnosed with leishmaniosis were retrospectively reviewed for cases that met the following inclusion criteria: identification of Leishmania organisms and/or DNA on cytological and/or histological specimens and/or a high anti-Leishmania antibody titre, compatible clinical findings and pathological abnormalities. RESULTS: Sixteen cats met the inclusion criteria, all of which were living in areas endemic for canine leishmaniosis. Systemic signs were present in 11 cases (68.8%). The most common clinical signs on presentation included cutaneous lesions in 12 cats (75%), ocular disease in six cats (37.5%) and anorexia in six cats (37.5%). A polyclonal gammopathy was noted in 12 cats (85.7%). Non-regenerative anaemia and renal abnormalities were present in six (37.5%) and five patients (31.3%), respectively. In nine cats (56.3%), immunosuppressive conditions/comorbidities were identified. The diagnosis was made in eight of the cats (50%) by cytology, but a combination of diagnostic tests was needed for definitive diagnosis in the remaining patients. Twelve cats (75%) were treated specifically for leishmaniosis. Five of the 12 cats (41.7%) did not improve with treatment. The median survival time in the group of patients treated specifically for leishmaniosis was 17 months. Median survival of patients treated with concomitant diseases was 13 months vs 41 months in those without, although this was not statistically significant (P = 0.557). CONCLUSIONS AND RELEVANCE: Presentation of FeL appears to be similar to canine leishmaniosis but with some specific features: ulcerative and nodular skin lesions are the predominant cutaneous signs; cats with immunosuppressive conditions or coexisting diseases were more commonly present than typically seen in dogs (mainly feline immunodeficiency virus). A combination of diagnostic tests may be needed for definitive diagnosis.

Sterile or nonantibiotic-responsive pustular dermatitis and canine leishmaniosis: a 14 case series description and a statistical association study on 2420 cases.

Background - No striking clinical and histopathological features of pustular dermatitis (PustD) in dogs suffering from canine leishmaniosis (CanL) have been identified; an association between CanL and PustD has not been demonstrated. Objectives - To characterize a series of dogs affected by CanL and pruritic PustD, and to evaluate a possible association between the two conditions. Conclusions - An association exists between PustD and CanL. At least in Leishmania-endemic areas, CanL should be ruled out before attempting an immunosuppressive treatment in dogs with PustD with the aforementioned characteristics. Staging of CanL through diagnostic procedures besides immunohistochemistry and PCR is recommended. Anti-leishmania treatment and short-to-medium courses of low-dose anti-inflammatory or immunomodulatory drugs are effective in controlling the clinical signs of PustD.

A retrospective study comparing histopathological and immunopathological features of nasal planum dermatitis in 20 dogs with discoid lupus erythematosus or leishmaniosis.

BACKGROUND: In areas endemic for leishmaniosis, discoid lupus erythematosus (DLE) and canine leishmaniosis (CanL) are the most common differential diagnoses for nasal planum erosive-ulcerative dermatitis in dogs. HYPOTHESIS/OBJECTIVE: To compare histopathological and immunopathological features of canine nasal planum erosive-ulcerative dermatitis with depigmentation due to DLE or CanL. ANIMALS: Nasal planum biopsies from dogs with nasal planum loss of architecture, depigmentation, swelling, erosions or ulcerations due to DLE (n = 14) or CanL (n = 6). METHODS: Sections of paraffin-embedded samples, stained with haematoxylin and eosin were reviewed. Samples were examined using antibodies targeting T cells (CD3), B cells (CD20), macrophages (Mac387) and class II major histocompatibility complex (MHC II). Histopathological and immunophenotypical findings were compared between DLE and CanL cases. RESULTS: Lichenoid and interface dermatitis were observed in both DLE and CanL cases. A nodular-to-diffuse, superficial and/or deep dermatitis with macrophages, lymphocytes and plasma cells was present only in CanL samples. CD20-positive cells predominated over CD3- and Mac387-positive cells in the two conditions. The percentage of dermal Mac387-positive cells was higher in CanL compared to DLE samples and the difference was statistically significant (P = 0.025). CONCLUSIONS/CLINICAL IMPORTANCE: In this study, similar histopathological and immunopathological findings were observed in dogs with nasal planum lesions due to DLE or CanL. Therefore, in areas endemic for leishmaniosis, the presence of the parasite should be investigated in canine nasal planum dermatitis showing clinical and histopathological features suggestive of DLE.

Rifampicin treatment of canine pyoderma due to multidrug-resistant meticillin-resistant staphylococci: a retrospective study of 32 cases.

BACKGROUND: Rifampicin has received increased interest in veterinary dermatology because of its activity against multidrug-resistant meticillin-resistant staphylococci (MRS). There is limited knowledge about the efficacy and safety of rifampicin in dogs. HYPOTHESIS/OBJECTIVE: To provide information on response to treatment and adverse effects in dogs treated with rifampicin for multidrug-resistant MRS pyoderma. ANIMALS: Thirty two dogs treated with rifampicin for rifampicin-susceptible multidrug-resistant MRS pyoderma. METHODS: Retrospective review of medical records, including alanine aminotransferase (ALT) and alkaline phosphatase (ALP) serum activity levels and total bilirubin concentrations, obtained before and throughout the treatment, was performed. RESULTS: Oral rifampicin as sole systemic antimicrobial therapy (median dose 5 mg/kg twice daily) was effective in 71.88% of cases. Topical antimicrobials were used in most cases. Median duration of rifampicin treatment was five weeks for superficial pyoderma and four weeks for deep pyoderma. Gastrointestinal signs were reported in 15% of treated dogs. Statistically significant increases of ALT (P = 0.045) and ALP (P = 0.0002) values after 3-4 weeks of treatment was observed. The median increase was equal to 0.3 and ×1.5 the upper limit of the reference ranges for ALT and ALP, respectively. CONCLUSIONS/CLINICAL IMPORTANCE: Oral rifampicin combined with topical antimicrobials can be considered an effective therapeutic option for canine superficial and deep pyoderma caused by rifampicin-susceptible multidrug-resistant MRS. Liver enzyme induction might be the most important cause of ALT and ALP increase associated with rifampicin therapy in dogs.

Serum detection of IgG antibodies against Demodex canis by western blot in healthy dogs and dogs with juvenile generalized demodicosis.

The aim of this study was to investigate the presence of canine immunoglobulins (Ig) G against Demodex proteins in the sera of healthy dogs and of dogs with juvenile generalized demodicosis (CanJGD) with or without secondary pyoderma. Demodex mites were collected from dogs with CanJGD. Protein concentration was measured and a western blot technique was performed. Pooled sera from healthy dogs reacted mainly with antigen bands ranging from 55 to 72 kDa. Pooled sera from dogs with CanJGD without secondary pyoderma reacted either with 10 kDa antigen band or 55 to 72 kDa bands. Pooled sera from dogs with CanJGD with secondary pyoderma reacted only with a 10 kDa antigen band. The results of this study suggest that both healthy dogs and dogs with CanJGD develop a humoral response against different proteins of Demodex canis.

Identification of a third feline Demodex species through partial sequencing of the 16S rDNA and frequency of Demodex species in 74 cats using a PCR assay.

BACKGROUND: 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. HYPOTHESIS/OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS AND CLINICAL IMPORTANCE: 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.

Pyogranulomatous mural folliculitis in a cat treated with methimazole.

An 11-year-old spayed female domestic shorthair cat was presented for polydipsia, hyperactivity and bilateral thyroid gland enlargement. Total T4 (TT4) was in the upper interval range; therefore, an early hyperthyroidism was suspected. A treatment trial with methimazole was started, as the owner refused further tests. Six months later the owner stopped the treatment. One year later, clinical signs persisted and TT4 was still in the upper interval range. Methimazole was re-introduced but 48 h later the cat presented non-pruritic alopecia with erythema, scales and perilesional yellowish crusts. Pyogranulomatous mural folliculitis was diagnosed by histopatological examination of the skin biopsies. Methimazole was withdrawn and macroscopic lesions healed and disappeared histologically in 15 days. An idiosyncratic drug reaction to methimazole was suspected. To the best of our knowledge, this is the first report of feline pyogranulomatous mural folliculitis likely secondary to an adverse drug reaction to methimazole administration.

Small Demodex populations colonize most parts of the skin of healthy dogs.

BACKGROUND: It is unproven that all dogs harbour Demodex mites in their skin. In fact, several microscopic studies have failed to demonstrate mites in healthy dogs. HYPOTHESIS/OBJECTIVES: Demodex canis is a normal inhabitant of the skin of most, if not all, dogs. This hypothesis was tested using a sensitive real-time PCR to detect Demodex DNA in the skin of dogs. ANIMALS: One hundred dogs living in a humane society shelter, 20 privately owned and healthy dogs and eight dogs receiving immunosuppressive or antineoplastic therapy. METHODS: Hair samples (250-300 hairs with their hair bulbs) were taken from five or 20 skin locations. A real-time PCR that amplifies a 166 bp sequence of the D. canis chitin synthase gene was used. RESULTS: The percentage of positive dogs increased with the number of sampling points. When a large canine population was sampled at five cutaneous locations, 18% of dogs were positive for Demodex DNA. When 20 skin locations were sampled, all dogs tested positive for mite DNA. Our study indicates that Demodex colonization of the skin is present in all dogs, independent of age, sex, breed or coat. Nevertheless, the population of mites in a healthy dog appears to be small. Demodex DNA was amplified from all 20 cutaneous points investigated, without statistically significant differences. CONCLUSIONS AND CLINICAL IMPORTANCE: Using a real-time PCR technique, Demodex mites, albeit in very low numbers, were found to be normal inhabitants of haired areas of the skin of healthy dogs.

Phylogenetic relationships in three species of canine Demodex mite based on partial sequences of mitochondrial 16S rDNA.

BACKGROUND: The historical classification of Demodex mites has been based on their hosts and morphological features. Genome sequencing has proved to be a very effective taxonomic tool in phylogenetic studies and has been applied in the classification of Demodex. Mitochondrial 16S rDNA has been demonstrated to be an especially useful marker to establish phylogenetic relationships. HYPOTHESIS/OBJECTIVES: To amplify and sequence a segment of the mitochondrial 16S rDNA from Demodex canis and Demodex injai, as well as from the short-bodied mite called, unofficially, D. cornei and to determine their genetic proximity. METHODS: Demodex mites were examined microscopically and classified as Demodex folliculorum (one sample), D. canis (four samples), D. injai (two samples) or the short-bodied species D. cornei (three samples). DNA was extracted, and a 338 bp fragment of the 16S rDNA was amplified and sequenced. RESULTS: The sequences of the four D. canis mites were identical and shared 99.6 and 97.3% identity with two D. canis sequences available at GenBank. The sequences of the D. cornei isolates were identical and showed 97.8, 98.2 and 99.6% identity with the D. canis isolates. The sequences of the two D. injai isolates were also identical and showed 76.6% identity with the D. canis sequence. CONCLUSION: Demodex canis and D. injai are two different species, with a genetic distance of 23.3%. It would seem that the short-bodied Demodex mite D. cornei is a morphological variant of D. canis.

Development of a real-time PCR to detect Demodex canis DNA in different tissue samples.

The present study reports the development of a real-time polymerase chain reaction (PCR) to detect Demodex canis DNA on different tissue samples. The technique amplifies a 166 bp of D. canis chitin synthase gene (AB 080667) and it has been successfully tested on hairs extracted with their roots and on formalin-fixed paraffin embedded skin biopsies. The real-time PCR amplified on the hairs of all 14 dogs with a firm diagnosis of demodicosis and consistently failed to amplify on negative controls. Eleven of 12 skin biopsies with a morphologic diagnosis of canine demodicosis were also positive. Sampling hairs on two skin points (lateral face and interdigital skin), D. canis DNA was detected on nine of 51 healthy dogs (17.6%) a much higher percentage than previously reported with microscopic studies. Furthermore, it is foreseen that if the number of samples were increased, the percentage of positive dogs would probably also grow. Moreover, in four of the six dogs with demodicosis, the samples taken from non-lesioned skin were positive. This finding, if confirmed in further studies, suggests that demodicosis is a generalized phenomenon in canine skin, due to proliferation of local mite populations, even though macroscopic lesions only appear in certain areas. The real-time PCR technique to detect D. canis DNA described in this work is a useful tool to advance our understanding of canine demodicosis.

Long term follow-up of dogs diagnosed with leishmaniosis (clinical stage II) and treated with meglumine antimoniate and allopurinol.

Twenty-three dogs with a diagnosis of leishmaniosis (clinical stage II) were treated with meglumine antimoniate and allopurinol and were followed up for 2-9 years. The treatment showed efficacy and the clinical condition of the dogs improved markedly in the first 3 months of treatment. Anti-Leishmania antibody titres declined slowly although most dogs remained seropositive 1 year after beginning treatment. Inter-individual variability in the evolution of the titres was very high. The dogs presented with three types of complications during the follow-up period. (1) Three dogs experienced relapses characterized by clinical signs, high anti-Leishmania titres and high parasitaemia. (2) Eight dogs presented immune-mediated lesions, such as uveitis, arthritis and cutaneous vasculitis; in all of these cases, the dogs had high titres of anti-Leishmania antibodies at diagnosis and during follow-up. (3) Three dogs presented xanthine urolithiasis most likely due to the allopurinol treatment. In one case the xanthine uroliths led to hydronephrosis and nephrectomy. The study demonstrated a long survival for dogs with leishmaniosis treated with the combination of meglumine antimoniate and allopurinol. Clinicians should pay special attention to the appearance of immune-mediated lesions, especially in dogs with sustained high antibody titres, and to urolithiasis.

Histopathological differences between canine idiopathic sebaceous adenitis and canine leishmaniosis with sebaceous adenitis.

Sebaceous adenitis (SA) may be idiopathic (ISA) or associated with other disorders. The purpose of the present study was to compare the cutaneous histopathology of SA in cases in which Leishmania organisms were detected by immunohistochemistry (IHC) with that of cases diagnosed as ISA. Skin sections of 29 patients were evaluated histologically and divided into two groups, one characterized by several epidermal and subepidermal lesions, a granulomatous to pyogranulomatous nodular to diffuse dermatitis involving the sebaceous glands and a positive IHC for Leishmania spp. The other group was characterized by orthokeratotic hyperkeratosis, follicular keratosis with different degrees of pyogranulomatous to granulomatous SA, lack of nodular dermatitis and a negative IHC for Leishmania spp. Hidradenitis was present in both groups. From these results it can be concluded that SA in canine Leishmaniosis (CL) is usually present together with a nodular to diffuse dermal infiltrate and epidermal and subepidermal lesions, and that SA in the absence of dermal inflammation is probably not associated with or suggestive of CL, even in regions where the disease is endemic.

Demodex injai infestation and dorsal greasy skin and hair in eight wirehaired fox terrier dogs.

Demodex injai mites were detected on trichoscopic examinations and/or deep skin scrapings in eight wirehaired fox terrier dogs with dorsal greasy skin and hair. Histological examination performed in five dogs revealed marked sebaceous gland hyperplasia with lympho-plasmacytic periadnexal dermatitis in all of them. One mite section was observed in one patient. Seven dogs were parasitologically cured after 2 to 7 months of oral ivermectin treatment. Greasy skin and hair resolved in four dogs, was partially reduced in two dogs and persisted in the remaining dog. Skin biopsies were repeated after parasitological cure in two dogs and revealed the persistence of sebaceous gland hyperplasia with mild lympho-plasmacytic periadnexal dermatitis and no parasites. Based on the findings in this case series, the terrier dog breed might be at increased risk for the development of D. injai mite infestation associated with dorsal greasy skin and hair, and microscopically with sebaceous gland hyperplasia. Persistence of sebaceous gland hyperplasia after parasitological cure in some patients suggested that this histological finding may not always be resulting from Demodex infestation. Moreover, low numbers of adult mites and variable clinical responses to acaricidal therapy suggested a contributory rather than a major role of D. injai in this skin condition. Dermatopathological diagnosis of sebaceous gland hyperplasia, particularly in case of dorsal trunk specimens from terrier dog breeds, warrants the search for D. injai mites on trichoscopic examinations and/or deep skin scrapings.

Hereditary cutaneous mucinosis in shar pei dogs is associated with increased hyaluronan synthase-2 mRNA transcription by cultured dermal fibroblasts.

Shar pei dogs are known for the distinctive feature of thick, wrinkled skin as a consequence of high dermal mucin content. Excessive dermal deposition of mucinous substance leading to severe skin folding, and/or to the more severe vesicular form characterized by dermal vesicles or bullae, is highly prevalent in this breed and is known as idiopathic mucinosis. Hyaluronic acid (HA) is the main component that accumulates in the dermis, and high levels of HA have also been detected in the serum of shar pei dogs. In this study, the cellular and molecular mechanisms underlying cutaneous mucinosis of shar pei dogs were investigated. Thirteen shar pei dogs and four control dogs of other breeds were included. In primary dermal fibroblast cultures, transcription of the family of hyaluronan synthases (HAS) involved in HA synthesis, and of hyaluronidases (HYAL) involved in HA degradation, were studied by reverse transcriptase polymerase chain reaction. The location of HA in cell cultures was studied by immunofluorescence and confocal laser microscopy. Dermal fibroblasts transcribed HAS2, HAS3, HYAL1 and HYAL2, but no amplification for HAS1 was found. A higher transcription of HAS2 was demonstrated in shar pei dogs compared with control dogs. By confocal microscopy, HA was detected as a more diffuse and intense network-like pattern of green fluorescence in the fibroblast cells of shar pei dogs in comparison with control dogs. Together, these results provide additional evidence that hereditary cutaneous mucinosis in shar pei dogs may be a consequence of over-transcription or increased activity of HAS2.

Malassezia spp. overgrowth in allergic cats.

A series of 18 allergic cats with multifocal Malassezia spp. overgrowth is reported: atopic dermatitis was diagnosed in 16, an adverse food reaction in another and one was euthanized 2 months after diagnosis of Malassezia overgrowth. All the cats were otherwise healthy and those tested (16 out of 18) for feline leukaemia or feline immunodeficiency virus infections were all negative. At dermatological examination, multifocal alopecia, erythema, crusting and greasy adherent brownish scales were variably distributed on all cats. Cytological examination revealed Malassezia spp. overgrowth with/without bacterial infection in facial skin (n = 11), ventral neck (n = 6), abdomen (n = 6), ear canal (n = 4), chin (n = 2), ear pinnae (n = 2), interdigital (n = 1) and claw folds skin (n = 1). Moreover, in two cats Malassezia pachydermatis was isolated in fungal cultures from lesional skin. Azoles therapy alone was prescribed in seven, azoles and antibacterial therapy in eight and azoles with both antibacterial and anti-inflammatory therapy in three of the cats. After 3-4 weeks of treatment, substantial reduction of pruritus and skin lesions was observed in all 11 cats treated with a combined therapy and in five of seven treated solely with azoles. Malassezia spp. overgrowth may represent a secondary cutaneous problem in allergic cats particularly in those presented for dermatological examination displaying greasy adherent brownish scales. The favourable response to treatment with antifungal treatments alone suggests that, as in dogs, Malassezia spp. may be partly responsible for both pruritus and cutaneous lesions in allergic cats.

Treatment with oral cyclosporin A of a case of vesicular cutaneous lupus erythematosus in a rough collie.

Cyclosporin A (CsA) is an immunosuppressive agent that can be used as alternative treatment to glucocorticoid therapy. This case report describes a case of vesicular cutaneous lupus erythematosus in a rough collie successfully controlled with oral CsA for more than 18 months.

Immune response to Leishmania infantum in healthy horses in Spain.

Leishmania infantum infection has recently been described in horses in Europe. We report the results of a study on the immune response to L. infantum in horses living in an area endemic for leishmaniosis in NE Spain. Two ELISAs using protein A and anti-horse IgG conjugates were adapted to measure specific antibodies to L. infantum in horse sera. A lymphocyte proliferation assay (LPA) of peripheral blood mononuclear cells to L. infantum antigen was also performed to detect specific cellular immune response to Leishmania. Anti-L. infantum antibodies were detected in the serum of 16 of the horses studied (n=112) using the protein A assay but not in the assay using the anti-horse IgG conjugate. Specific lymphocyte proliferation was observed in 20 out of 55 horses. This study shows that horses in the area studied mount specific immune responses to L. infantum, and must therefore be considered among the species exposed to the parasite in this region. The infrequency of leishmaniosis in horses suggests that the immune response in this species is effective in controlling the infection.