PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

Demodicosis is a skin condition caused by Demodex mite, frequently diagnosed in clinical routine. The purpose of this study was to compare the clinical and histological manifestations of localized and generalized demodicosis in dogs, relating the amount of mites and microscopic lesions. The study group was formed by 46 dogs, 28 with generalized demodicosis, and 18 with the localized form of the disease, all of them with positive skin scrapings. Macroscopic lesions data in dermatological form were noted, and skin samples were collected for microscopic study. The histopathological analysis was individually performed by three reviewers without intercommunication, being considered the result that more occurred. Alopecia, scaling, erythema, and crusting were the most common clinical lesions in both forms of the disease. Histological severe dermatitis occurred especially in dogs with localized and generalized disease that had concomitant pyoderma and Demodex sp. mites were visualized with intensity moderate and severe in the most dogs with both forms of the diseases. Perifolliculitis was the most evident microscopic follicular change in this study, followed by folliculitis and furunculosis wall, which had higher relative occurrence in dogs with localized demodicosis. According to the results obtained, the severity of histologic lesions does not necessarily correspond to the clinical presentation of the disease, in addition to the amount of mites that apparently is not indicative of localized or generalized clinical lesions, and cannot differentiate clinical disease by histopathology.

• Canine demodicosis dermatology dermatopathology dogs histology parasitoses

Abstract in Portuguese:

Demodicose é uma afecção cutânea causada pelo ácaro Demodex sp. diagnosticada com frequência na rotina clínica veterinária. Objetivou-se descrever as manifestações clínicas e histológicas de cães com demodicose nas formas localizada e generalizada, relacionando a quantidade de ácaros e os achados microscópicos ao quadro clínico. Foram estudados 46 cães, sendo 28 com demodicose generalizada e 18 com a forma localizada da doença, dos quais todos possuíam raspados de pele positivo. Destes caninos foram anotados dados de lesões macroscópicas em ficha dermatológica e coletaram-se amostras de pele para estudo microscópico. A análise histológica foi realizada por três avaliadores e os dados registrados sem comunicação entre os mesmos, sendo considerado o resultado que mais ocorreu. Alopecia, descamação, eritema e crostas foram lesões clínicas comuns às duas formas de apresentação da doença que mais ocorreram. Inflamação histológica dermal grave ocorreu especialmente nos cães com doença localizada e generalizada que possuíam piodermite concomitante e ácaros Demodex sp. foram visualizados com intensidade entre moderada e acentuada na maioria dos cães com ambas as formas da enfermidade. Perifoliculite foi a alteração folicular microscópica mais evidenciada nos caninos deste estudo, seguida por foliculite mural e furunculose que tiveram maior ocorrência relativa nos cães com demodicose localizada. De acordo com os resultados obtidos verificou-se que a gravidade das lesões histológicas não corresponde necessariamente à forma de apresentação clínica da enfermidade, além disso, a quantidade de ácaros não demonstrou ser indicativa de lesões clínicas localizadas ou generalizadas, bem como não é possível diferenciar a doença clínica através do exame histopatológico.

• Demodicose canina dermatologia dermatohistopatologia histologia caninos parasitoses

Abstract in English:

ABSTRACT.- Souza C.P., Ramadinha R.H.R. & Scott F.B. 2014. Clinical and parasitological evaluation of pour-on fluazuron and ivermectin for treating canine demodicosis. Pesquisa Veterinária Brasileira 34(11):1094-1100. Departamento de Parasitologia Animal, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, BR-465 Km 7, Seropédica, RJ 23890-000, Brazil. E-mail: clarissaps@globo.com The objective of the study was to evaluate the efficacy of pour-on formulations of fluazuron and ivermectin in different therapeutic protocols for treatment of demodicosis by means of quantifying mites with skin scraping, histological and clinical evaluation in dogs. Eighteen dogs with skin scrapings positive for Demodex canis were evaluated, divided into three groups. All the animals were treated every 14 days, completing 6 treatments for each animal (days 0, 14, 28, 42, 56 and 70). In group 1, pour-on 2.5% fluazuron was used at the dose of 20mg/kg; in the group 2 pour-on 2.5% fluazuron at a dose of 20 mg/kg in association with pour-on 0.5% ivermectin at the dose of 0.6mg/kg; and in group 3, pour-on 0.5% ivermectin alone was used, at the dose of 0.6mg/kg. The treatment was evaluated and monitored through skin scrapings and clinical follow-up of the lesions every 14 days for 84 days, and through histopathological examination at the end of each treatment protocol. The success rate was defined as the percentage of dogs in each group that had negative skin scrapings after the treatment: this was 16.67% for group 1, and 50% for groups 2 and 3. The reduction in mite counts reached effectiveness of 67.66%, 88.99% and 84.29% for groups 1, 2 and 3 respectively. The Wilcoxon test showed that there was a significant difference between the number of mites before and after treatment in groups 2 and 3. The histopathological examination revealed that only group 1 showed no significant difference in the intensity of infestation between days 0 and 84. Clinically, there was no significant difference between the evaluation before and after treatment in the three groups. Pour-on 2.5% fluazuron and pour-on 0.5% ivermectin were not effective for treating canine demodicosis, either in association or as single therapy, when applied every 14 days for a period of 70 days. Quantification of mites using skin scrapings and histological evaluation proved to be ineffective, either one as sole therapeutic evaluation parameters, for canine demodicosis.

• Demodex canis fluazuron ivermectin demodiciose canina ivermectina

Abstract in Portuguese:

RESUMO.- Souza C.P., Ramadinha R.H.R. & Scott F.B. 2014. Clinical and parasitological evaluation of pour-on fluazuron and ivermectin for treating canine demodicosis. [Avaliação clínica e parasitológica do fluazuron e da ivermectina pour-on no tratamento da demodiciose canina.] Pesquisa Veterinária Brasileira 34(11):1094-1100. Departamento de Parasitologia Animal, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, BR-465 Km 7, Seropédica, RJ 23890-000, Brazil. E-mail: clarissaps@globo.com O objetivo do presente estudo foi avaliar a eficácia do fluazuron e da ivermectina pour-on em diferentes protocolos terapêuticos no tratamento da demodiciose, através da quantificação de ácaros por raspados cutâneos e exames histológicos, além da avaliação dos cães. Foram avaliados 18 cães com raspados cutâneos positivos para o ácaro Demodex canis, divididos em três grupos. Todos os animais foram tratados a cada 14 dias, totalizando seis tratamentos em cada cão (Dias 0, 14, 28, 42, 56 e 70). No grupo 1 foi utilizado fluazuron 2,5% pour-on na dosagem de 20mg/kg; no grupo 2 foi empregado fluazuron 2,5% pour-on na dosagem de 20mg/kg associado a ivermectina 0,5% pour-on, na dosagem de 0,6mg/kg e, no grupo 3, somente ivermectina 0,5% pour-on 0,6mg/kg. Raspados cutâneos e acompanhamento clínico das lesões foram realizados a cada 14 dias por 84 dias e realizado exame histopatológico ao final de cada protocolo terapêutico. A taxa de sucesso foi definida pela porcentagem de cães em cada grupo com raspados negativos ao final do tratamento, que foi 16,67% para o grupo 1 e 50% para os grupos 2 e 3. A redução na contagem no número de ácaros alcançou eficácia de até 67,66%; 88,99% e 84,29%, nos grupos 1, 2 e 3, respectivamente. O teste de Wilcoxon mostrou que houve diferença significativa entre a quantidade de ácaros antes e após o tratamento nos grupos 2 e 3. No exame histopatológico apenas o grupo 1 não apresentou diferença significativa na intensidade da infestação entre os dias 0 e 84. Clinicamente não houve diferença significativa entre as avaliações antes e após o tratamento dos três grupos. O fluazuron 2,5% pour-on e a ivermectina 0,5% pour-on associados ou como terapia única, não foram eficazes no tratamento da demodiciose canina, quando aplicados a cada 14 dias em um período de 70 dias. A quantificação de ácaros através do exame parasitológico em raspado cutâneo e em exame histopatológico demonstrou-se ineficaz como parâmetro isolado de avaliação pós-terapêutica para demodiciose canina.

Abstract in English:

Faccini J.L.H., Santos A.C.G. & Bechara G.H. 2004. [Bovine demodicosis in the state of Paraíba, northeastern Brazil.] Demodicose bovina no Estado da Paraíba. Pesquisa Veterinária Brasileira 24(3):149-152. Depto Parasitologia Animal, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: faccini@ufrrj.br Cases of bovine demodicosis caused by Demodex bovis were reported in a Sindhi herd from December 1989 to January 1992. Both localized and generalized forms were diagnosed. This is the first report of the generalized form in Brazil. In the first two years, demodicosis was diagnosed only in cattle < 2 years old, whereas animals of all ages were positive in the last two years. Prevalence varied from 20.4% (11/54) to 53.1% (26/49) and 13.2% (12/91) to 14.8% (9/61) for cattle < 2 years old and > 2 years old, respectively. Clinical signs varied from a few small nodules to a thickened skin with soft large nodules in the localized and generalized forms, respectively. Main microscopic features of the nodules in the generalized form consisted of acanthosis with hyperqueratosis, chronic sebaceous adenitis, subcutaneous muscular necrosis, focal cellular degeneration of the epidermis basal layer and presence of large number of mites inside the lumen of dilated hair follicles. In addition, a chronic perifoliculitis was observed, characterized by lymphoplasmocytic infiltrate which also contained macrophages and neutrophils. It is suggested that poor nutrition and stress due to prolonged drought probably contributed to the increase of susceptibility of the herd to mite infestation.

• Demodex bovis demodicosis cattle pathology Brazil.

Abstract in Portuguese:

Faccini J.L.H., Santos A.C.G. & Bechara G.H. 2004. [Bovine demodicosis in the state of Paraíba, northeastern Brazil.] Demodicose bovina no Estado da Paraíba. Pesquisa Veterinária Brasileira 24(3):149-152. Depto Parasitologia Animal, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: faccini@ufrrj.br Cases of bovine demodicosis caused by Demodex bovis were reported in a Sindhi herd from December 1989 to January 1992. Both localized and generalized forms were diagnosed. This is the first report of the generalized form in Brazil. In the first two years, demodicosis was diagnosed only in cattle < 2 years old, whereas animals of all ages were positive in the last two years. Prevalence varied from 20.4% (11/54) to 53.1% (26/49) and 13.2% (12/91) to 14.8% (9/61) for cattle < 2 years old and > 2 years old, respectively. Clinical signs varied from a few small nodules to a thickened skin with soft large nodules in the localized and generalized forms, respectively. Main microscopic features of the nodules in the generalized form consisted of acanthosis with hyperqueratosis, chronic sebaceous adenitis, subcutaneous muscular necrosis, focal cellular degeneration of the epidermis basal layer and presence of large number of mites inside the lumen of dilated hair follicles. In addition, a chronic perifoliculitis was observed, characterized by lymphoplasmocytic infiltrate which also contained macrophages and neutrophils. It is suggested that poor nutrition and stress due to prolonged drought probably contributed to the increase of susceptibility of the herd to mite infestation.