Immunohistochemical Detection of Intralesional Antigens of Ovine Gammaherpesvirus-2 in Cattle with Sheep-associated Malignant Catarrhal Fever.

Sheep-associated malignant catarrhal fever (SA-MCF) is a severe lymphoproliferative disease of ruminants caused by ovine gammaherpesvirus-2 (OvHV-2). Since the initial identification of SA-MCF there has been extensive research related to the pathogenesis of OvHV-2, based primarily on serological and molecular assays associated with typical histopathological findings. The monoclonal antibody (MAb-15A) binds to a common epitope in MCF viruses and is used frequently in serological investigations. However, the utilization of this antibody to detect antigens of OvHV-2 in tissues has not been examined. Accordingly, this study standardized an immunohistochemical assay using MAb-15A to identify antigens of OvHV-2 in tissues of cattle (n = 5) with SA-MCF. All animals developed acute neurological signs, without ocular and nasal manifestations, and had nucleic acids of OvHV-2 in brain tissue detected by polymerase chain reaction. The principal histopathological findings were lymphocytic nephritis (n = 5), widespread arterial proliferation and vasculitis (n = 5), lymphocytic portal hepatitis (n = 3), non-suppurative meningoencephalitis (n = 2) and atrophic enteritis with cryptal necrosis and dilation (n = 2). Intralesional intracytoplasmic antigens of OvHV-2 were identified within multiple epithelial cells of the kidneys of all animals, the intestines of animals with and without atrophic enteritis, and within epithelial cells of bile ducts in animals with lymphocytic hepatitis. Additionally, there was positive intracytoplasmic immunoreactivity within histiocytes and lymphocytes in several tissues. These findings suggest that the MAb-15A detects antigens of OvHV-2 within epithelial cells and leucocytes in several organs. Moreover, this assay would contribute significantly towards understanding of the pathogenesis of SA-MCF and may be used for retrospective studies. Additionally, angiopathy in SA-MCF may be a progressive lesion, which may terminate in luminal occlusion and probably occurs irrespectively of the eye and head form of MCF.

Prevalence of foot disorders in lactating Jersey cows raised in semi-confinement.

BACKGROUND AND AIM: To establish prevention strategies, recording the prevalence of foot injuries within a herd should be the starting point in determining the risk factors involved in digital diseases. This study aimed to assess the prevalence of claw disorders in lactating Jersey cows raised in a semi-confinement system. MATERIALS AND METHODS: Five hundred and eighty-four digits were examined from 73 lactating Jersey cows. The lameness score system was used to assess each cow while walking and on standing position, and digital lesions were evaluated with the cows restrained in a hydraulic cattle chute. RESULTS: The prevalence of digital lesions was 93.1%. Among the 68 affected cows, only 21 were lame. Of the 584 digits examined, 970 lesions were recorded, corresponding to 13.3% lesions per cow and 1.66% injuries per digit. Forty-eight cows (65.7%) had lesions in all digits, and 92.8% of digits had at least one lesion. Lesions in digits of fore limbs were more common (55.3%) (p<0.0001) than those of hind limbs (44.7%). Foot injuries in medial digits of the fore limbs were more prevalent (56.8%) (p<0.001) than in the lateral digits (43.2%). The lesions' occurrence was similar in both medial and lateral digits of the hind limbs (p=0.8347). The primary diseases observed were heel horn erosion (53.8%), white line disease (19.3%), and double sole (12.4%), which together accounted for 92.4% and 84.9% of foot disorders diagnosed in the fore and hind limbs, respectively. Other digital diseases occurred less frequently. CONCLUSION: The prevalence of foot disorders in lactating Jersey cows raised in semi-confinement systems was high. This could be due to the lack of preventive trimming, infectious diseases, and nutritional problems.

Presença do genoma de BoHV-5 no líquido cefalorraquidiano de bovinos com meningoencefalite herpética / Presence of BoHV-5 genome in cerebrospinal fluid of cattle with herpetic meningoencephalitis

The diagnosis of bovine herpesvirus 5 (BoHV-5) encephalitis is confirmed after death by laboratory methods applied to brain fragments. Alternative methods to confirm ante-mortem diagnosis are important because the disease is not always lethal. The aim of this study was to investigate whether the presence of the virus genome in the cerebrospinal fluid (CSF) detected by polymerase chain reaction (PCR) might be admitted as a method for ante-mortem diagnosis. CSF samples were taken from 14 animals suffering from BoHV-5 encephalitis, diagnosed by characteristic histopathological lesions in the brain and by identification of the virus genome by PCR in different portions of the brain. Virus DNA was detected in the CSF of 21.42% (3/14) of the evaluated animals. Ante-mortem detection of the virus genome in the CSF showed low sensitivity to confirm the diagnosis. The diagnosis is confirmed by a positive result but a negative one does not discard the disease.(AU)

Cerebral cryptococcomas in a cow.

Cerebral cryptococcomas are described in a 5-year-old mixed-breed cow without manifestations of systemic cryptococcosis. Two cryptococcomas were observed grossly. Microscopical examination revealed accumulations of yeast that were morphologically consistent with Cryptococcus neoformans. Immunohistochemistry characterized the organisms as C. neoformans var. grubii.