The Middle East respiratory syndrome (MERS) emerged in Saudi Arabia in 2012, caused by a zoonotically transmitted coronavirus (CoV). Over 1,900 cases have been reported to date, with ∼36% fatality rate. Lack of autopsies from MERS cases has hindered understanding of MERS-CoV pathogenesis. A small animal model that develops progressive pulmonary manifestations when infected with MERS-CoV would advance the field. As mice are restricted to infection at the level of DPP4, the MERS-CoV receptor, we generated mice with humanized exons 10-12 of the mouse locus. Upon inoculation with MERS-CoV, human DPP4 knockin (KI) mice supported virus replication in the lungs, but developed no illness. After 30 serial passages through the lungs of KI mice, a mouse-adapted virus emerged (MERS) that grew in lungs to over 100 times higher titers than the starting virus. A plaque-purified MERS clone caused weight loss and fatal infection. Virus antigen was observed in airway epithelia, pneumocytes, and macrophages. Pathologic findings included diffuse alveolar damage with pulmonary edema and hyaline membrane formation associated with accumulation of activated inflammatory monocyte-macrophages and neutrophils in the lungs. Relative to the parental MERS-CoV, MERS viruses contained 13-22 mutations, including several within the spike (S) glycoprotein gene. S-protein mutations sensitized viruses to entry-activating serine proteases and conferred more rapid entry kinetics. Recombinant MERS bearing mutant S proteins were more virulent than the parental virus in hDPP4 KI mice. The hDPP4 KI mouse and the MERS provide tools to investigate disease causes and develop new therapies.

Inflammation is a common feature in several types of lung disease and is a frequent end point to validate lung disease models, evaluate genetic or environmental impact on disease severity, or test the efficacy of new therapies. Questions relevant to a study should be defined during experimental design and techniques selected to specifically address these scientific queries. In this review, the authors focus primarily on the breadth of techniques to evaluate lung inflammation that have both clinical and preclinical applications. Stratification of approaches to assess lung inflammation can diminish weaknesses inherent to each technique, provide data validation, and increase the reproducibility of a study. Specialized techniques (eg, imaging, pathology) often require experienced personnel to collect, evaluate, and interpret the data; these experts should be active contributors to the research team through reporting of the data. Scoring of tissue lesions is a useful method to transform observational pathologic data into semiquantitative or quantitative data for statistical analysis and enhanced rigor. Each technique to evaluate lung inflammation has advantages and limitations; understanding these parameters can help identify approaches that best complement one another to increase the rigor and translational significance of data.

Abstract. A 6-month-old, female, intact Rottweiler dog was presented to the Iowa State University Veterinary Teaching Hospital for a progressive history of abnormal behavior and generalized ataxia. At necropsy, there was eosinophilic infiltration of the brain and spinal cord, most severe in the medulla oblongata, cerebellum, and cervical spinal cord. Infiltrates of eosinophils were also present in the liver and small intestines. The dog was diagnosed with idiopathic eosinophilic meningoencephalomyelitis based on cerebrospinal fluid analysis, histopathology, and special stains to exclude etiologic agents.Key words: Eosinophil; meningitis; meningoencephalomyelitis; Rottweilers.Eosinophilic meningoencephalitis is a rare condition in veterinary medicine; the etiology in the majority of canine cases is often undetermined. Protozoan and nematode parasites can occasionally cause eosinophilic encephalitis in dogs.5 In humans, the most common cause of eosinophilic meningitis is a result of infection with a rat lungworm (Angiostrongylus cantonensis). This infection is usually nonfatal and occurs after ingesting third-stage larvae of the lungworm in contaminated produce or inadequately cooked snails. 7 In the past 2 decades, there have been several reports of an idiopathic form of eosinophilic meningitis that has been shown to affect dogs, cats, and cattle. [1][2][3]6,[8][9][10] In these cases, no infectious etiology has been identified; however, Rottweiler and Golden Retriever dogs appear to be overrepresented, indicating a possible breed predisposition. Dogs with eosinophilic meningoencephalitis often have signs consistent with both brain and spinal cord disease; however, no report has histologically documented the spinal cord changes. In the current report, a young Rottweiler dog with an acute onset of a severe and fatal eosinophilic meningoencephalomyelitis is described.A 6-month-old, 20 kg, female, intact Rottweiler presented to the referring veterinarian with a 6-day history of mild ataxia, lethargy, and decreased appetite. Blood work was performed, including complete blood cell count (CBC) and biochemical profile. The following abnormalities were noted: hypercholesterolemia (328 mg/dl, reference interval: 125-260 mg/dl) and moderate eosinophilia (4,200/ml, reference interval: 0-600/ml). A urinalysis was also performed, which revealed the presence of white blood cells, red blood cells, and bacteria in the sediment. The dog was given clindamycin (300 mg orally, every 12 hr), kept for a few hours for observation, and then sent home. The following day, the dog presented to Iowa State University Veterinary Teaching Hospital (ISU-VTH, Ames, Iowa) with worsening tetraparesis and proprioceptive ataxia.On presentation to the ISU-VTH, the dog was in lateral recumbency, but was quiet, alert, and responsive. On physical examination, the dog had a heart rate of 100 beats per min, a rectal temperature of 40.6uC, and was panting. Generalized muscle tremors were present along with apparent hypersensitivity to touch and sound. On ne...

Allograft inflammatory factor 1 (AIF1) is a commonly used marker for microglia in the brains of humans and some animal models but has had limited applications elsewhere. We sought to determine whether AIF1 can be used as a macrophage marker across common laboratory animal species and tissues. We studied tissues (that is, spleen, liver, and lung) with defined macrophage populations by using an AIF1 immunostaining technique previously validated in human tissue. Tissues were collected from various mouse strains ( = 20), rat strains ( = 15), pigs ( = 4), ferrets ( = 4), and humans ( = 4, lung only). All samples of liver had scattered immunostaining in interstitial cells, consistent with resident tissue macrophages (Kupffer cells). Spleen samples had cellular immunostaining of macrophages in both the red and white pulp compartments, but the red pulp had more immunostained cellular aggregates and, in some species, increased immunostaining intensity compared with white pulp. In lung, alveolar macrophages had weak to moderate staining, whereas interstitial and perivascular macrophages demonstrated moderate to robust staining. Incidental lesions and tissue changes were detected in some sections, including a tumor, inducible bronchus-associated lymphoid tissue, and inflammatory lesions that demonstrated AIF1 immunostaining of macrophages. Finally, we compared AIF1 immunostaining of alveolar macrophages between a hypertensive rat model (SHR strain) and a normotensive model (WKY strain). SHR lungs had altered intensity and distribution of immunostaining in activated macrophages compared with macrophages of WKY lungs. Overall, AIF1 immunostaining demonstrated reproducible macrophage staining across multiple species and tissue types. Given the increasing breadth of model species used to study human disease, the use of cross-species markers and techniques can reduce some of the inherent variability within translational research.

Background Hematologic variables are often analyzed in animal analogues during the investigation of complex disease etiologies such as necrotizing enterocolitis. However, reference intervals (RI) can vary depending on animal strain, age, and sampling site. Reference intervals have been published for adult C57BL/6J mice, but not newborn C57BL/6J mice. Objectives The purpose of the present study was to determine hematologic RI in newborn C57BL/6J mice up to day 35. Methods C57BL/6J mice founders from The Jackson Laboratory were bred at the University of Iowa. Blood samples were obtained via facial vein sampling at postnatal days 0 (p0), p7, p14, p21, p28, or young adulthood (p35). CBCs were determined with the Sysmex XT-2000iV analyzer within 30 minutes of blood collection at a 1:10 dilution. Statistics were determined using nonparametric methods following ASVCP guidelines. Results Hematologic RI were determined for each of the 6 groups (n=247, n≥39 per group). Significantly higher values for HGB, RBC, and PLT counts were observed with advancing developmental age. Total WBC counts remained relatively stable during the first 35 days of life. However, WBC differential counts were dominated by neutrophils and lymphocytes in the younger mice, with a trend towards a lymphocytic leukogram on day 35. Conclusions These results illustrate the dynamic changes in hematologic variables during murine development after birth. Utilization of age-specific RI is advised when evaluating data derived from experimental perinatal mouse models.