Equine herpesvirus-1 is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). In recent years, there has been an apparent increase in the incidence of EHM in North America, with serious consequences for horses and the horse industry. This consensus statement draws together current knowledge in the areas of pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment.Key words: Abortion; Horse; Immunology; Infectious diseases; Myeloencephalopathy; Respiratory tract; Viral.E quine herpesvirus-1 (EHV-1) infection is ubiquitous in most horse populations throughout the world, and causes disease in horses and extensive economic losses through frequent outbreaks of respiratory disease, abortion, neonatal foal death, and myeloencephalopathy. [1][2][3][4] Infections caused by EHV-1 are particularly common in young performance horses, and typically result in establishment of latent infection within the 1st weeks or months of life 5 with subsequent viral reactivation causing clinical disease and viral shedding during periods of stress. The relevant effects of this virus on the equine population are 3-fold. Firstly, sporadic occurrence of mild respiratory disease associated with pyrexia, principally affecting horses under 2 years of age, can lead to interruptions in athletic training programs; this is economically the least important manifestation of EHV-1 disease. Secondly, abortion occurring during the 3rd trimester of pregnancy, results in important economic losses. Thirdly, outbreaks of neurological disease (equine herpes myeloencephalopathy or EHM) cause suffering and loss of life and also lead to extensive movement restrictions, disrupting breeding or training schedules and causing management difficulties at training centers, racetracks, and horse events. A perceived increase in the incidence of EHM outbreaks in North America in recent years has led to the proposal that it could represent an emerging disease threat. 6 The recent increased impact of EHM in North America provided the impetus for this consensus statement. The renewed focus on EHV-1 infection and its control, new developments in our understanding of this virus and its behavior in horses, and the development of new viral detection technologies have resulted in renewed challenges for clinicians in responding to the threat of EHV-1 and to outbreaks. In an attempt to address this challenge, this statement is structured as a series of critical questions, which we believe capture the key challenges for equine clinicians and scientists. The responses seek to distill current evidence-based knowledge Abbreviations:CTL cytotoxic T-lymphocyte EHM equine herpesvirus myeloencephalopathy EHV-1 equine herpesvirus-1 Consensus Statements of the American College of Veterinary Internal Medicine (ACVIM) provide the veterinary community with up-to-date information on the pathophysiolo...

The objective of this study was to evaluate the association between uterine disease and indicators of neutrophil (PMN) and systemic energy status in dairy cows. Peripheral blood (120 mL) was collected weekly from 84 Holstein cows for PMN isolation and plasma collection from calving until 42 d in milk (DIM). The final analysis included 80 cows. Of those, 20 cows were classified as having metritis (fetid uterine discharge and fever), 15 as having subclinical endometritis (SCE; >or=10% PMN on uterine cytology), and 45 as healthy controls. Plasma haptoglobin concentration was increased only in cows that developed metritis. Neutrophil glycogen content was reduced in cows developing metritis compared with healthy cows on the day of calving and at 7 and 42 DIM. Cows with SCE had lower PMN glycogen content than healthy cows at 7, 28, and 42 DIM. Blood glucose was affected by disease status within parity. Primiparous metritis cows had greater blood glucose concentrations than healthy primiparous cows. Multiparous metritis cows tended to have lower blood glucose concentration than multiparous SCE cows. Cows that developed metritis and SCE had or tended to have greater NEFA and BHBA than healthy cows, mainly around calving. At calving, cows that developed metritis had higher plasma estradiol concentration than healthy cows and greater plasma cortisol than cows that had SCE. Plasma insulin was not affected. Plasma glucagon was increased for SCE cows. Cows that developed uterine disease experienced a greater degree of negative energy balance and had decreased lower intracellular PMN glycogen levels, which could be a major predisposing factor for disease because of decreased availability of oxidative fuels.

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Mesenchymal progenitor cells (MPCs) are often characterized using surface markers after expansion and treatment in culture. There are no studies directly comparing gene and protein markers in undifferentiated samples during the very early phases of culture. The goal of this study was to evaluate temporal gene and protein expression changes during establishment of equine MPC cultures. Bone marrow aspirate was obtained from 35 horses and processed by density gradient centrifugation. In freshly isolated bone marrow, mononuclear cells had variable expression of CD44, CD11a/CD18, CD90, and CD45RB cell surface molecules. After 2 h of culture, bone marrow mononuclear cells had a phenotype of CD44(hi), CD29(hi), CD90(lo), CD11a/CD18(hi), and CD45RB(lo). Isolated mononuclear cells were analyzed by flow cytometry and RT-qPCR at 2, 7, 14, 21, and 30 days of culture. At all culture time points, gene expression was in agreement with cell surface protein expression. In established cultures of MPCs, cells remained robustly positive for CD44 and CD29. The proportion of positive cells and the mean fluorescence intensity of positive cells increased in CD90 expression as MPC cultures became more homogeneous. Inversely, the population of cells in culture decreased expression of CD11a/CD18 and CD45RB molecules over time. The decreased expression of the latter molecules makes these useful negative markers of established MPC cultures under normal expansion conditions. The results of this study demonstrate numerous dynamic changes in cell surface molecule expression during early establishment of MPC populations, which may aid to improve MPC isolation methods for research or therapeutic applications.

This study describes the clinical and immunologic findings of 14 affected horses (average age 10.7 +/- 4.4 years) of both genders (six females, eight males) and different breeds (eight Thoroughbreds, four Quarter Horses, one Warmblood, one Pony). Serial immunological testing in peripheral blood revealed persistent, severe B cell lymphopenia (mean 1.3 +/- 2.3% positive cells) in all patients. Serum IgG (range <200 to 800 mg/dL) and IgM (

Summary A 21‐year‐old Thoroughbred gelding was examined for intermittent fever, lethargy, inappetance and weight loss. Initial diagnostic evaluation revealed pancytopenia (anaemia, thrombocytopenia and neutropenia), hyperfibrinogenaemia and multifocal pulmonary nodules. Bacterial and fungal culture and viral isolation on transtracheal aspirate samples were negative, consistent with either pulmonary neoplasia, idiopathic granulomatous pneumonia or equine multinodular pulmonary fibrosis (EMPF). Bone marrow evaluation was consistent with pancytopenia due to a combination of peripheral consumption/destruction and suppression/destruction of progenitor cells at the level of the marrow. Pancytopenia resolved and clinical signs improved transiently with immunosuppressive corticosteroid therapy, but the horse deteriorated rapidly one month after presentation and was subjected to euthanasia. Necropsy findings were consistent with EMPF, and equine herpesvirus‐5 (EHV‐5) DNA was found in both the lung and bone marrow. The specific role of EHV‐5 in the development of the pulmonary pathology in EMPF and the pancytopenia in this horse is unclear, but an aberrant host immune/inflammatory response to EHV‐5 infection may be important.

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