Macroscopic Distribution, Histopathology and Viral Antigen Expression in Dogs with Canine Distemper Virus-induced Hyperkeratosis in Nasodigital and Other Regions.

Cutaneous hyperkeratosis is one of the many clinicopathological manifestations of canine distemper and is characterized by thickening and hardening of the skin, predominantly in nasodigital areas. Although this lesion may rarely affect other regions, this has been poorly characterized. Twelve dogs with canine distemper and cutaneous hyperkeratosis, necropsied at an anatomical pathology service, were investigated. Twenty-two cutaneous hyperkeratotic foci were observed on footpads (11/22), nasal planum (3/22), haired skin on the snout (2/22), periocular region (2/22), ventral abdomen (2/22), scrotum (1/22) and vulva (1/22). The dogs had one (5/12), two (4/12) or three (3/12) regions concomitantly affected. Orthokeratotic hyperkeratosis was a predominant histopathological feature in 17 dogs, occasionally accompanied by other lesions, including inclusion bodies (14/17), epidermal hyperplasia (9/17) and keratinocyte hydropic degeneration (6/17). Canine distemper virus antigen was expressed in at least one skin lesion in 10 dogs. Fourteen (14/17) hyperkeratotic foci were immunopositive while three (3/17) were immunonegative. Viral antigen expression was most common in the sweat glands (13/17), epidermis (11/17) and vascular endothelial cells or pericytes (8/17). Histological findings and antigen detection were similar among nasodigital and other regions. We emphasize the importance of clinicopathological recognition of these lesions for the initial suspicion of canine distemper, thereby facilitating early treatment.

Histopathological Features of Spinal Cord Lesions in Dogs with Distemper-Associated Demyelinating Leucoencephalomyelitis.

Demyelinating leucoencephalomyelitis (DLEM) is one of the pathological presentations of canine distemper, but its histological characteristics and topographical distribution of spinal cord injuries have been poorly explored. Seventeen dogs submitted for necropsy to a veterinary pathology service (2006-2008) and diagnosed with distemper-associated DLEM were investigated. Seventy-two of 231 spinal cord sections from these animals had histological lesions, which consistently affected the white matter. The lumbosacral region was mostly affected (13/17), followed by the thoracolumbar (11/17), cervical (9/17) and cervicothoracic (9/17) regions. Among the 72 affected cord sections, lesions in the lateral (42/72) and dorsal funiculi (31/72) were the most common. Demyelination (17/17), astrocytosis (17/17), microgliosis (17/17), gemistocytes (11/17) and non-suppurative inflammation (10/17) were frequently seen in the white matter. Grey matter changes were less common, and included gliosis (8/17), non-suppurative inflammation (7/17) and malacia (5/17). Acute lesions were most prevalent (13/17) but it was common (10/17) for the same dog to have lesions at different stages of evolution in distinct spinal cord regions. Pathological changes in several spinal cords did not correlate with the reported clinical signs and some dogs did not present with spinal cord-related clinical signs. Our results highlight important aspects of the distribution and morphology of spinal cord lesions in dogs with distemper-associated DLEM, and may assist clinicians and pathologists in the diagnosis of spontaneous cases of this important infectious disease and contribute to further studies concerning distemper pathogenesis.

Caracterização histoquímica no diagnóstico da babesiose bovina por Babesia bovis / Histochemical characterization in the diagnosis of bovine babesiosis by Babesia bovis

A babesiose é uma doença hemolítica transmitida por carrapatos e causada por protozoários intraeritrocitários do gênero Babesia. Esta é uma doença de incidência elevada na Região Sul do Brasil e responsável por perdas econômicas consideráveis. O diagnóstico clínico-patológico pode ser feito através da demonstração do parasito pelo exame de esfregaços sanguíneos ou de tecidos frescos. Entretanto, com frequência, somente órgãos fixados em formol são remetidos para laboratórios de patologia, o que impossibilita a realização do esfregaço. O principal objetivo deste estudo foi encontrar técnicas histoquímicas alternativas e capazes de aprimorar a evidenciação de Babesia bovis intraeritrocitária em tecidos fixados em formol. Para este estudo, foram analisadas retrospectivamente amostras de tecidos de 50 casos de necropsias de bovinos, as quais haviam sido fixadas em formol e processadas rotineiramente para histopatologia. Os casos foram divididos em um grupo controle, constituído por 12 casos de babesiose cerebral com substância cinzenta encefálica róseo-cereja característica (grupo A), e 38 casos sugestivos de tristeza parasitária bovina (grupo B), conforme os protocolos de necropsias. Foram testadas as técnicas histoquímicas de Azul Alciano, Azul de Metileno, Azul de Toluidina, Giemsa, Gram (método de McCallum-Goodpasture), Grocott, Ácido Periódico de Schiff e Ziehl-Neelsen. Dentre estas, observou-se que as técnicas de Azul de Metileno e Azul de Toluidina permitiram observar características morfológicas e tintoriais de maneira mais nítida, auxiliando na identificação de B. bovis. Adicionalmente, foram estabelecidos vários parâmetros clínico-epidemiológicos e anatomopatológicos da babesiose por B. bovis.(AU)

Babesiosis is a hemolytic tick-borne disease caused by intraerythrocytic protozoal parasites of the genus Babesia. This is a disease of high incidence in the southern Brazil and responsible for considerable economic losses. Clinical-pathological diagnosis can be made by demonstrating the parasite by examining blood smears or fresh tissues. However, frequently, only formalin-fixed organs are sent to pathology laboratories, which makes it impossible to perform the smears. The main objective of this study was to find alternative histochemical techniques capable to improve the identification of intraerythrocytic Babesia bovis in histological sections. For this study, tissue samples from 50 bovine necropsy cases were retrospectively analyzed, which had been fixed in formalin and routinely processed for histopathology. The cases were divided into a control group, consisting of 12 cases of cerebral babesiosis with characteristic pink-cherry gray matter (group A), and 38 cases suggestive of cattle tick fever (group B), according to necropsy protocols. Histochemical techniques of Alcian Blue, Methylene Blue, Toluidine Blue, Giemsa, Gram (McCallum-Goodpasture method), Grocott, Periodic Acid of Schiff and Ziehl-Neelsen were tested. Among these, it was observed that the techniques of Methylene Blue and Toluidine Blue allowed to observe morphological and dye characteristics in a clearer way, aiding in the identification of B. bovis. In addition, several clinical-epidemiological and anatomopathological parameters of babesiosis caused by B. bovis were established.(AU)