Equine gamma herpesvirus presence and viral load are not associated with equine glandular gastric disease

OBJECTIVE

To investigate the role of equine herpesvirus-2 (EHV-2) and equine herpesvirus-5 (EHV-5) in equine glandular gastric disease (EGGD) by visualizing and quantifying these gamma herpesviruses in EGGD-affected and normal glandular gastric mucosa of horses. A secondary objective was to describe the histopathological abnormalities in the equine gastric glandular mucosa in horses with EGGD.

ANIMALS

29 horses (n = 21 postmortem and 8 gastroscopy) categorized as normal (11), EGGD (12), or both EGGD and equine squamous gastric disease (6).

METHODS

Glandular gastric mucosal samples were collected from horses by gastroscopy or postmortem. Histopathology and in situ hybridization targeting EHV-2 and EHV-5 were performed on grossly normal and abnormal glandular gastric mucosa. The number of in situ hybridization-positive cells per millimeter squared of tissue was calculated. Evaluators were blinded to groups.

RESULTS

Glandular gastric tissues from horses without EGGD had higher viral loads in the mucosa than normal or abnormal tissues from EGGD horses. There was no difference in viral loads for EHV-2 or EHV-5 between grossly or endoscopically normal to abnormal gastric tissues within horses with EGGD. Lymphocytic plasmacytic gastritis was the most common histopathological abnormality, with only 3 horses having mucosal disruption (glandular ulcer or erosion).

CLINICAL RELEVANCE

Equine gamma herpesviruses are unlikely to play a role in the pathophysiology of EGGD. EGGD is frequently inflammatory with occasional mucosal disruption (ulcer or erosion).

Proteomic profiling of membrane vesicles from Mycobacterium avium subsp. paratuberculosis: Navigating towards an insilico design of a multi-epitope vaccine targeting membrane vesicle proteins

Bacteria typically produce membrane vesicles (MVs) at varying levels depending on the surrounding environments. Gram-negative bacterial outer membrane vesicles (OMVs) have been extensively studied for over 30 years, but MVs from Gram-positive bacteria only recently have been a focus of research. In the present study, we isolated MVs from Mycobacterium avium subsp. paratuberculosis (MAP) and analyzed their protein composition using LC-MS/MS. A total of 316 overlapping proteins from two independent preparations were identified in our study, and topology prediction showed these cargo proteins have different subcellular localization patterns. When MVs were administered to bovine-derived macrophages, significant up-regulation of pro-inflammatory cytokines was observed via qRT-PCR. Proteome functional annotation revealed that many of these proteins are involved in the cellular protein metabolic process, tRNA aminoacylation, and ATP synthesis. Secretory proteins with high antigenicity and adhesion capability were mapped for B-cell and T-cell epitopes. Antigenic, Immunogenic and IFN-γ inducing B-cell, MHC-I, and MHC-II epitopes were stitched together through linkers to form multi-epitope vaccine (MEV) construct against MAP. Strong binding energy was observed during the docking of the 3D structure of the MEV with the bovine TLR2, suggesting that the putative MEV may be a promising vaccine candidate against MAP. However, in vitro and in vivo analysis is required to prove the immunogenic concept of the MEV which we will follow in our future studies. SIGNIFICANCE: Johne's disease is a chronic infection caused by Mycobacterium avium subsp. paratuberculosis that has a potential link to Crohn's disease in humans. The disease is characterized by persistent diarrhea and enteritis, resulting in significant economic losses due to reduced milk yield and premature culling of infected animals. The dairy industry in the United States alone experiences losses of approximately USD 250 million due to Johne's disease. The current vaccine against Johne's disease is limited by several factors, including variable efficacy, limited duration of protection, interference with diagnostic tests, inability to prevent infection, and logistical and cost-related challenges. Nevertheless, a multiepitope vaccine design approach targeting M. avium subsp. paratuberculosis has the potential to overcome these challenges and offer improved protection against Johne's disease.

Experimental Induction of Acute Acanthamoeba castellanii Keratitis in Cats

Purpose

To develop a feline model of acute Acanthamoeba keratitis using methods that replicate natural routes of infection transmission.

Methods

Corneal Acanthamoeba castellanii inoculation was performed by three methods: topical inoculation with Acanthamoeba solution following corneal abrasion, placement of a contaminated contact lens for 7 days, and placement of a contaminated contact lens for 7 days following corneal abrasion. Sham inoculations with parasite-free medium and sterile contact lenses were also performed. Cats were monitored by ocular examination and in vivo corneal confocal microscopy for 21 days post-inoculation. Corneal samples were collected at intervals for microbiologic assessment, histopathology, and immunohistochemistry.

Results

All cats in the corneal abrasion groups developed clinical keratitis. Clinical ocular disease was inconsistently detected in cats from the contaminated contact lens only group. Initial corneal lesions were characterized by multifocal epithelial leukocyte infiltrates. Ocular lesions progressed to corneal epithelial ulceration and diffuse stromal inflammation. After 14 days, corneal ulcerations resolved, and stromal inflammation consolidated into multifocal subepithelial and stromal infiltrates. Corneal amoebae were detected by culture, in vivo confocal microscopy, histopathology, and immunohistochemistry in cats with keratitis. Neutrophilic and lymphocytic keratoconjunctivitis with lymphoplasmacytic anterior uveitis were identified by histopathology. Coinfection with aerobic bacteria was detected in some, but not all, cats with keratitis. Ocular disease was not detected in the sham inoculation groups.

Conclusions

Feline Acanthamoeba keratitis is experimentally transmissible by contaminated contact lenses and topical inoculation following corneal epithelial trauma.

Translational Relevance

Experimentally induced acute Acanthamoeba keratitis in cats is clinically and histopathologically similar to its human counterpart.

Metacarpophalangeal Joint Pathology and Bone Mineral Density Increase with Exercise but Not with Incidence of Proximal Sesamoid Bone Fracture in Thoroughbred Racehorses

Proximal sesamoid bone (PSB) fracture is the leading cause of fatal musculoskeletal injury in Thoroughbred racehorses in Hong Kong and the US. Efforts are underway to investigate diagnostic modalities that could help identify racehorses at increased risk of fracture; however, features associated with PSB fracture risk are still poorly understood. The objectives of this study were to (1) investigate third metacarpal (MC3) and PSB density and mineral content using dual-energy X-ray absorptiometry (DXA), computed tomography (CT), Raman spectroscopy, and ash fraction measurements, and (2) investigate PSB quality and metacarpophalangeal joint (MCPJ) pathology using Raman spectroscopy and CT. Forelimbs were collected from 29 Thoroughbred racehorse cadavers (n = 14 PSB fracture, n = 15 control) for DXA and CT imaging, and PSBs were sectioned for Raman spectroscopy and ash fraction measurements. Bone mineral density (BMD) was greater in MC3 condyles and PSBs of horses with more high-speed furlongs. MCPJ pathology, including palmar osteochondral disease (POD), MC3 condylar sclerosis, and MC3 subchondral lysis were greater in horses with more high-speed furlongs. There were no differences in BMD or Raman parameters between fracture and control groups; however, Raman spectroscopy and ash fraction measurements revealed regional differences in PSB BMD and tissue composition. Many parameters, including MC3 and PSB bone mineral density, were strongly correlated with total high-speed furlongs.

Leptospira borgpetersenii Leucine-Rich Repeat Proteins Provide Strong Protective Efficacy as Novel Leptospiral Vaccine Candidates

Leucine-rich repeat (LRR) proteins are advocated for being assessed in vaccine development. Leptospiral LRR proteins were identified recently in silico from the genome of Leptospira borgpetersenii serogroup Sejroe, the seroprevalence of leptospiral infections of cattle in Thailand. Two LRR recombinant proteins, rKU_Sej_LRR_2012M (2012) and rhKU_Sej_LRR_2271 (2271), containing predicted immunogenic epitopes, were investigated for their cross-protective efficacies in an acute leptospirosis model with heterologous Leptospira serovar Pomona, though, strains from serogroup Sejroe are host-adapted to bovine, leading to chronic disease. Since serovar Pomona is frequently reported as seropositive in cattle, buffaloes, pigs, and dogs in Thailand and causes acute and severe leptospirosis in cattle by incidental infection, the serogroup Sejroe LRR proteins were evaluated for their cross-protective immunity. The protective efficacies were 37.5%, 50.0%, and 75.0% based on the survival rate for the control, 2012, and 2271 groups, respectively. Sera from 2012-immunized hamsters showed weak bactericidal action compared to sera from 2271-immunized hamsters (p < 0.05). Therefore, bacterial tissue clearances, inflammatory responses, and humoral and cell-mediated immune (HMI and CMI) responses were evaluated only in 2271-immunized hamsters challenged with virulent L. interrogans serovar Pomona. The 2271 protein induced prompt humoral immune responses (p < 0.05) and leptospiral tissue clearance, reducing tissue inflammation in immunized hamsters. In addition, protein 2271 and its immunogenic peptides stimulated splenocyte lymphoproliferation and stimulated both HMI and CMI responses by activating Th1 and Th2 cytokine gene expression in vaccinated hamsters. Our data suggest that the immunogenic potential renders rhKU_Sej_LRR_2271 protein a promising candidate for the development of a novel cross-protective vaccine against animal leptospirosis.

Mediastinal Serous Cavity Mesothelioma in Two Dogs

The mediastinal serous cavity (MSC)-well documented but seldom recognized in the caudal mediastinum-is embryologically derived from the omental bursa. Mesothelioma arising from the MSC in two dogs is described. Both dogs presented with acute life-threatening hemorrhagic pleural effusion. Contrast computed tomography revealed a large solitary spherical-to-cylindrical tumor in the caudal mediastinum with variably thick, contrast-enhancing walls with lobular to frond-like proliferations that arose circumferentially and projected internally into a single, variably sized, fluid-attenuating lumen. The wall and lumen corresponded to the serous membrane and serous cavity of the MSC. Surgical exploration confirmed that both tumors arose from the mediastinum. Both had similar histologic findings, and special stains were necessary for definitive diagnosis. The tumor was nonresectable in one dog, and it was euthanized intraoperatively. The other survived 7 mo. An MSC mesothelioma should be considered a possible cause of hemothorax in dogs that may be detected on thoracic radiography and computed tomography. Differential diagnoses include esophageal foreign body or neoplasm, paraesophageal diaphragmatic hernia, MCS empyema, and pulmonary adenocarcinoma, with thoracic computed tomography helping to rule out foreign body and diaphragmatic hernia. For confirmed neoplasms, histochemistry and immunohistochemistry should be performed to differentiate between mesothelioma and pulmonary adenocarcinoma.

Proximal sesamoid bone microdamage is localized to articular subchondral regions in Thoroughbred racehorses, with similar fracture toughness between fracture and controls

OBJECTIVE

To determine whether proximal sesamoid bone (PSB) microdamage and fracture toughness differ between Thoroughbred racehorses sustaining PSB fracture and controls.

STUDY DESIGN

Cadaveric case-control.

ANIMALS

Twenty-four Thoroughbred racehorses (n = 12 PSB fracture, n = 12 control).

METHODS

Proximal sesamoid bones were dissected, and gross pathological changes and morphological measurements were documented. High-speed exercise history data were evaluated. Microdamage was assessed in fracture, fracture-contralateral limb (FXCL) and control PSBs using whole bone lead uranyl acetate (LUA) staining with micro-CT imaging or basic fuchsin histological analysis. Fracture toughness mechanical testing was carried out in 3-point-bending of microbeams created from PSB flexor cortices. Data were analyzed using ordinal logistic and linear regression models.

RESULTS

Microdamage was detected most commonly in the articular subchondral region of PSBs via LUA micro-CT and basic fuchsin histology. There were no differences in microdamage between FXCL and control PSBs. Fracture toughness values were similar for FXCL (1.31 MPa√m) and control (1.35 MPa√m) PSBs. Exercise histories were similar except that horses sustaining fracture spent a greater percentage of their careers in rest weeks.

CONCLUSION

Microdamage was detected in the articular region of PSBs but was not greater in horses sustaining catastrophic PSB fracture. Fracture toughness of PSB flexor cortices did not differ between FXCL and control PSBs.

CLINICAL SIGNIFICANCE

Although uncommon, microdamage is localized to the articular region of Thoroughbred racehorse PSBs. Catastrophic PSB failure is not associated with lower PSB flexor cortex fracture toughness.

Bacterial culture and immunohistochemical detection of bacteria and endotoxin in cats with suppurative cholangitis-cholangiohepatitis syndrome

OBJECTIVE

To characterize the frequency and type of bacterial infection by culture- and immunohistochemical (IHC)-based methods and determine the impact of infection on clinical features and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS).

ANIMALS

168 client-owned cats with S-CCHS (cases).

PROCEDURES

Clinical features, bacterial culture results, culture-inoculate sources, and survival details were recorded. Cases were subcategorized by comorbidity (extrahepatic bile duct obstruction, cholelithiasis, cholecystitis, ductal plate malformation, biopsy-confirmed inflammatory bowel disease, and biopsy-confirmed pancreatitis) or treatment by cholecystectomy or cholecystoenterostomy. Culture results, bacterial isolates, Gram-stain characteristics, and IHC staining were compared among comorbidities. Lipoteichoic acid IHC staining detected gram-positive bacterial cell wall components, and toll-like receptor expression IHC reflected pathologic endotoxin (gram-negative bacteria) exposure.

RESULTS

Clinical features were similar among cases except for more frequent abdominal pain and lethargy in cats with positive culture results and pyrexia, abdominal pain, and hepatomegaly for cats with polymicrobial infections. Bacteria were cultured in 93 of 135 (69%) cats, with common isolates including Enterococcus spp and Escherichia coli. IHC staining was positive in 142 of 151 (94%) cats (lipoteichoic acid, 107/142 [75%]; toll-like receptor 4, 99/142 [70%]). With in-parallel interpretation of culture and IHC-based bacterial detection, 154 of 166 (93%) cats had bacterial infections (gram-positive, 118/154 [77%]; gram-negative, 111/154 [72%]; polymicrobial, 79/154 [51%]). Greater frequency of bacterial isolation occurred with combined tissue, bile, and crushed cholelith inoculates. Infection and gram-positive bacterial isolates were associated with significantly shorter long-term survival times.

CLINICAL RELEVANCE

S-CCHS was associated with bacterial infection, pathologic endotoxin exposure, and frequent polymicrobial infection in cats. Combined tissue inoculates improved culture detection of associated bacteria.

Pathogenesis, MicroRNA-122 Gene-Regulation, and Protective Immune Responses After Acute Equine Hepacivirus Infection

BACKGROUND AND AIMS

Equine hepacivirus (EqHV) is phylogenetically the closest relative of HCV and shares genome organization, hepatotropism, transient or persistent infection outcome, and the ability to cause hepatitis. Thus, EqHV studies are important to understand equine liver disease and further as an outbred surrogate animal model for HCV pathogenesis and protective immune responses. Here, we aimed to characterize the course of EqHV infection and associated protective immune responses.

APPROACH AND RESULTS

Seven horses were experimentally inoculated with EqHV, monitored for 6 months, and rechallenged with the same and, subsequently, a heterologous EqHV. Clearance was the primary outcome (6 of 7) and was associated with subclinical hepatitis characterized by lymphocytic infiltrate and individual hepatocyte necrosis. Seroconversion was delayed and antibody titers waned slowly. Clearance of primary infection conferred nonsterilizing immunity, resulting in shortened duration of viremia after rechallenge. Peripheral blood mononuclear cell responses in horses were minimal, although EqHV-specific T cells were identified. Additionally, an interferon-stimulated gene signature was detected in the liver during EqHV infection, similar to acute HCV in humans. EqHV, as HCV, is stimulated by direct binding of the liver-specific microRNA (miR), miR-122. Interestingly, we found that EqHV infection sequesters enough miR-122 to functionally affect gene regulation in the liver. This RNA-based mechanism thus could have consequences for pathology.

CONCLUSIONS

EqHV infection in horses typically has an acute resolving course, and the protective immune response lasts for at least a year and broadly attenuates subsequent infections. This could have important implications to achieve the primary goal of an HCV vaccine; to prevent chronicity while accepting acute resolving infection after virus exposure.

Determination of correlation of proximal sesamoid bone osteoarthritis with high-speed furlong exercise and catastrophic sesamoid bone fracture in Thoroughbred racehorses

OBJECTIVE

To examine whether proximal sesamoid bone (PSB) articular cartilage and bone osteoarthritic changes or palmar osteochondral disease (POD) scores were associated with exercise history and catastrophic PSB fracture in Thoroughbred racehorses.

SAMPLES

PSBs from 16 Thoroughbred racehorses (8 with and 8 without PSB fracture).

PROCEDURES

Exercise history was collected, and total career high-speed furlongs was used as the measure of total exercise per horse. At necropsy, medial and lateral condyles of the third metacarpus from each forelimb were assigned a POD score, followed by imaging with micro-CT for evaluation of osteophyte size. Three investigators that were blinded to the type of PSB (fracture or no fracture) used the Osteoarthritis Research Society International (OARSI) scoring system to evaluate acellularity, chondrocyte necrosis, cartilage fibrillation, chondrone formation, safranin O stain uptake, and tidemark advancement of 1 central sagittal tissue section/PSB (4 PSBs/horse). Cartilage thickness and bone necrosis were scored on the basis of histologic examination.

RESULTS

POD score, osteophyte size score, percentage of bone necrosis, tidemark advancement, chondrone formation, and total OARSI score were greater in horses with more accrued total career high-speed furlongs. Scores for POD, osteophyte size, fibrillation, acellularity, chondrone formation, and total OARSI were greater for horses with PSB fracture.

CONCLUSIONS AND CLINICAL REVELANCE

OARSI scoring revealed that more advanced osteoarthritic changes strongly correlated with total career high-speed furlongs and PSB fracture. However, the effect of exercise was dominant, suggesting that exercise history will be important to include in future models that aim to assess risk factors for catastrophic PSB fracture.

Acanthamoeba sclerokeratitis in a cat

CASE DESCRIPTION

A 12-year-old neutered male domestic shorthair cat with chronic anterior uveitis and secondary glaucoma of the right eye was examined for persistent blepharospasm 2 weeks after corneal debridement and grid keratotomy for nonhealing superficial ulcerative keratitis.

CLINICAL FINDINGS

Examination of the right eye revealed a central superficial corneal ulcer associated with corneal epithelial and subepithelial infiltrates and mild aqueous flare. Structures consistent with amoeboid cysts and trophozoites were detected in the cornea by in vivo confocal microscopy. Suppurative keratitis was identified cytologically. An Acanthamoeba spp was isolated through culture and identified by a PCR assay of corneal specimens.

TREATMENT AND OUTCOME

Symptomatic and antiamoebic (polyhexamethylene biguanide 0.02% ophthalmic solution) treatments were instituted. Over the following 6 weeks, the cat lost vision in the affected eye and lesions progressed to nonulcerative stromal keratitis associated with a dense paracentral corneal stroma ring infiltrate and anterior lens luxation. The globe was enucleated, and lymphoplasmacytic sclerokeratitis, anterior uveitis, and retinal detachment were noted. Acanthamoeba organisms were detected within the corneal stroma and anterior sclera with histologic and immunohistochemical stains. The amoebae were classified to the Acanthamoeba T4 genotype by DNA sequencing. The cat had no medical problems attributed to Acanthamoeba infection over 36 months after enucleation, until the cat was lost to follow-up.

CLINICAL RELEVANCE

Naturally acquired Acanthamoeba sclerokeratitis is described in a cat for the first time. Acanthamoeba infection should be considered for cats with superficial corneal disease refractory to appropriate treatments and especially occurring after ocular trauma, including keratotomy.

Equine leptospirosis: Experimental challenge of Leptospira interrogans serovar Bratislava fails to establish infection in naïve horses

BACKGROUND

Little information is available about experimental inoculation of leptospirosis in horses and the pathogenicity of Leptospira interrogans serovar Bratislava in this host.

OBJECTIVES

To determine the serological, clinical, pathological and haematological responses of horses to L. interrogans serovar Bratislava strain PigK151.

STUDY DESIGN

Randomised controlled in vivo experiment.

METHODS

Ten seronegative female foals were divided into 2 groups, control (n = 4) and challenged (n = 6). The challenged group received 1 × 10⁹ leptospires divided equally between topical ocular and intraperitoneal injections. Blood and urine samples were analysed. The temperature was recorded daily for the first 9 days, then weekly. Sera were tested by microscopic agglutination test (MAT). Automated complete blood count, differential and chemistry panel were performed. Histopathological analysis was performed on sections of liver, kidney, urinary bladder, uterine body and pineal gland. Sample culturing was performed from blood, urine, liver, kidney, reproductive tract and vitreous humour.

RESULTS

No pyrexia was noted. PCR and culture were negative from all samples. Differences between groups were found in CBC, differential counts and serum biochemistry panel (or profile), suggesting that leptospiral challenge triggered an inflammatory response. No evidence of leptospirosis was found from histopathological analysis. All challenged foals developed a humoral response. The MAT allowed the confirmation of the infecting serovar at a later stage, but it also revealed cross-reactive results that were further explained by genomic analysis.

MAIN LIMITATIONS

This experimental challenge had two main limitations: (a) the results might have varied if another strain from the same serovar had been used and (b) the use of another route of infection and a higher bacterial dose might have achieved colonisation.

CONCLUSIONS

Based on these findings, it may suggest that L. interrogans serovar Bratislava is neither pathogenic nor host-adapted serovar for horses, although these results might have varied if another strain from the same serovar had been used instead.

Clinical characteristics and long-term outcome of E. coli-associated granulomatous ileocolitis in dogs: five cases (2010-2014)

OBJECTIVES

To describe the clinical characteristics and long-term outcome of Escherichia coli-associated granulomatous ileocolitis in dogs.

METHODS

Retrospective review of medical records from dogs with periodic acid-Schiff positive (PAS+) granulomatous ileocolitis and mucosally invasive E. coli in the ileum and colon. Initial bacterial colonisation was evaluated using fluorescence in situ hybridization (FISH) in all dogs and corroborated with colonic and/or ileal culture, when performed.

RESULTS

Four boxer dogs and 1 French Bulldog with PAS+ granulomatous ileocolitis (GIC) were evaluated. All dogs had chronic diarrhoea refractory to empirical therapy. Ileocolonoscopy revealed mucosal haemorrhage and ulceration in the ileum (3/4) and colon (5/5). E. coli were visualised as clusters within the ileal and colonic mucosa. Complete (CR, 4/5) or partial (PR, 1/5) clinical response to fluoroquinolones was noted in all dogs within 30 days. CR was sustained in three of four dogs (median disease-free interval 40 months, range 16 to 60). Two dogs relapsed while receiving fluoroquinolones. Repeat biopsy isolated multidrug-resistant, mucosally invasive E. coli in the ileum (1/2) and colon (2/2). Targeted antimicrobial therapy was associated with long-term PR (78 months) in both dogs.

CLINICAL SIGNIFICANCE

Concurrent E. coli-associated granulomatous inflammation in the ileum and colon did not impart a poor clinical outcome or lack of response to the conventional standard of care for granulomatous colitis in dogs that were aggressively diagnosed and treated. Clinical outcome was influenced by antimicrobial resistance, with response dependent upon antimicrobial therapy informed by susceptibility testing.

Clinical, clinicopathologic, and hepatic histopathologic features associated with probable ketoconazole-induced liver injury in dogs: 15 cases (2015-2018)

OBJECTIVE

To characterize clinical, clinicopathologic, and hepatic histopathologic features and outcome for dogs with probable ketoconazole-induced liver injury.

ANIMALS

15 dogs with suspected ketoconazole-induced liver injury that underwent liver biopsy.

PROCEDURES

Medical record data were summarized regarding signalment, clinical signs, clinicopathologic and hepatic histopathologic findings, concurrent medications, ketoconazole dose, treatment duration, and outcome.

RESULTS

Median age and body weight were 8.2 years (range, 5 to 15 years) and 13.0 kg (28.6 lb; range, 8.2 to 38.0 kg [18.0 to 83.6 lb]), respectively. The most common breed was Cocker Spaniel (n = 5). All dogs received ketoconazole to treat cutaneous Malassezia infections. Median daily ketoconazole dose was 7.8 mg/kg (3.5 mg/lb; range, 4.4 to 26.0 mg/kg [2.0 to 11.8 mg/lb]), PO. Treatment duration ranged from 0.3 to 100 cumulative weeks (intermittent cyclic administration in some dogs); 6 dogs were treated for ≤ 10 days. Common clinical signs included lethargy, anorexia, and vomiting. All dogs developed high serum liver enzyme activities. Hepatic histopathologic findings included variable lobular injury, mixed inflammatory infiltrates, and conspicuous aggregates of ceroid-lipofuscin-engorged macrophages that marked regions of parenchymal damage. Five dogs developed chronic hepatitis, including 3 with pyogranulomatous inflammation. Of the 10 dogs reported to have died at last follow-up, survival time after illness onset ranged from 0.5 to 165 weeks, with 7 dogs dying of liver-related causes.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings for dogs with hepatotoxicosis circumstantially associated with ketoconazole treatment suggested proactive monitoring of serum liver enzyme activities is advisable before and sequentially after initiation of such treatment.

Evaluation of new leptospiral antigens for the diagnosis of equine leptospirosis: An approach using pan-genomic analysis, reverse vaccinology and antigenic selection

BACKGROUND

The current gold standard diagnostic test for leptospirosis is the microscopic agglutination test (MAT), which has many drawbacks; therefore, the development of a better and easier serological test for leptospirosis is needed.

OBJECTIVES

To apply reverse vaccinology (RV) and antigenic selection on the assortment of leptospiral targets and evaluate their potential for use as reagents for the diagnosis of equine leptospirosis.

STUDY DESIGN

Cross-sectional study.

METHODS

The antigenic selection parameters were: proteins with antigenicity score ≥0.5 (VaxiJen), at least one B cell epitope and size between 10 and 275 KDa. New leptospiral proteins were cloned, expressed and serologically screened against equine sera (n = 128) on a single analysis and comparative combinations. Sensitivity (Se) and specificity (Sp), accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated. A BLAST with nucleotide and protein sequences was used to identify the serovar or species specificity.

MAIN LIMITATIONS

This cross-sectional analysis had three main limitations: (a) The equine sera used in these tests were limited to sera submitted to the Animal Health Diagnosis Center and were only tested against seven serovars; (b) MAT results were considered being 'perfect', and the highest titre presented was considered being the infecting serovar, which may not hold true; (c) The strains used to represent the serovars and the limited number of different serovars and species included in the genetic analysis, which leads to the possibility that these proteins might be present in different species or serovars that perhaps would be seroprevalent in another geographic region.

CONCLUSIONS

The new leptospiral antigens described in this research could increase the sensitivity and specificity of ELISA for detection of Leptospira exposure and the detection of leptospirosis in horses along with support from other clinical signs. Some of these new antigens might be used to improve the detection of infecting serovar.

Leptospirosis trends in China, 2007-2018: A retrospective observational study

Leptospirosis is one of the most common and neglected tropical waterborne diseases in China, causing serious economic losses, and constituting a significant public health threat. Leptospirosis has recently received increased attention and is considered a re-emerging infectious disease in many countries. The incidence of leptospirosis among people suggests that occupation, age, season, sex and water recreational activities are significant risk factors. The aim of this study was to describe the epidemiological profiles of leptospirosis in China during the 2007-2018 period. The morbidity data of leptospirosis by age, season (month), gender, occupation and geographic location (different provinces) were obtained from the public health science data centre of China for subsequent epidemiological analysis. The results indicate that the incidence of leptospirosis has shown a slow downward trend from 2007 to 2018, but morbidity rates were still relatively high (0.0660-0.0113). The incidence of leptospirosis varied in different provinces of China; cases localized mainly to the Southern and Central provinces, areas with warm weather and ample rainfall. Older people (aged 60-75), males, farmers, students and field workers were high-risk populations. During the 2007-2018 observation period, morbidity rates increased beginning in May, remained at high levels in August and September and decreased after November. The present investigation highlights the re-emergence of leptospirosis in some provinces of China (especially in Yunnan and Fujian) and shows that leptospirosis remains a serious public health threat. The results of this study should enhance measures taken for the prevention, control, and surveillance of leptospirosis in China.

Effects of recombinant bovine interleukin-8 (rbIL-8) treatment on health, metabolism, and lactation performance in Holstein cattle IV: Insulin resistance, dry matter intake, and blood parameters

We have shown in 2 independent studies that cows who received recombinant bovine interleukin-8 (rbIL-8) administered intrauterinely shortly after parturition have a significant and long-lasting increase in milk yield. In the present study, we hypothesized that the increased milk production associated with rbIL-8 treatment is a consequence of increased postpartum dry matter intake (DMI) and orchestrated homeorhetic changes that prioritize milk production. Cows were enrolled into 1 of 3 treatment groups: those assigned to the control group (CTR; n = 70) received an intrauterine (IU) administration of 500 mL of Dulbecco's phosphate-buffered saline (DPBS) solution and 1 mL of DPBS solution intravenously (IV; jugular vein), those assigned to the rbIL-8 IV group (rbIL8-IV, n = 70) received an IV injection of 167 μg of rbIL-8 and 500 mL of DPBS solution IU, and cows assigned to the rbIL-8 IU group (rbIL8-IU, n = 70) received an IU administration with 1,195 μg of rbIL-8 diluted in 499.5 mL of DPBS solution and 1 mL of DPBS solution IV. Animals were housed in a tiestall from calving to 30 d in milk (DIM) to measure DMI. Blood samples were collected daily from calving to 7 DIM and weekly until 28 DIM. Insulin resistance was evaluated using an intravenous glucose tolerance test and intravenous insulin challenge test (IVICT) in a subgroup of cows (n = 20/treatment) at 10 and 11 DIM, respectively. Additionally, liver biopsy samples were taken at 14 DIM from the same subgroup of cows to measure triglyceride levels and cell proliferation and apoptosis. Cows treated with rbIL8-IU produced more milk (CTR = 36.9 ± 1.5; rbIL8-IU = 38.5 ± 1.5; rbIL8-IV = 36.6 ± 1.5 kg/d), energy-corrected milk (CTR = 42.9 ± 0.9; rbIL8-IU = 46.1 ± 0.8; rbIL8-IV = 43.7 ± 0.9 kg/d), and fat-corrected milk (CTR = 44.3 ± 0.9; rbIL8-IU = 47.8 ± 0.9; rbIL8-IV = 45.2 ± 0.9 kg/d) yields when compared with CTR cows, and no differences were observed between rbIL8-IV and CTR cows. The administration of rbIL8-IU significantly increased DMI compared with CTR (CTR = 18.8 ± 0.3; rbIL8-IU = 19.9 ± 0.3; rbIL8-IV = 19.3 ± 0.3 kg/d). Recombinant bIL-8 treatment did not affect glucose, insulin, or fatty acids (i.e., IVICT only) concentrations or their area under the curve in response to an intravenous glucose tolerance test and IVICT when compared with CTR. Moreover, rbIL-8 treatment administered IU or IV increased liver triglyceride levels. Additionally, cows treated with rbIL8-IU tended to have lower odds of developing hyperketonemia (odds ratio = 0.46, 95% confidence interval: 0.19 to 1.10), lower odds of clinical ketosis and displaced abomasum combined (odds ratio = 0.17, 95% confidence interval: 0.03 to 0.89), and lower odds of diseases combined (odds ratio = 0.43, 95% confidence interval: 0.21 to 0.86) when compared with CTR. We conclude that the administration of rbIL8-IU increases DMI, milk production, fat-corrected milk, and energy-corrected milk while improving overall health during the postpartum period. This study supports the use of rbIL-8 administered IU shortly after calving to improve health and production responses in lactating cows.

Biodegradable amino acid-based poly(ester amine) with tunable immunomodulating properties and their in vitro and in vivo wound healing studies in diabetic rats' wounds

The objective of this study is to design a new family of biodegradable synthetic polymeric biomaterials for providing a tunable inhibition of macrophage's nitric oxide synthase (NOS) pathway. l-Arginine (Arg) is the common substrate for NOS and arginase. Both two metabolic pathways participate in the wound healing process. An impaired wound healing, such as diabetic or other chronic wounds is usually associated with an overproduction of NO by macrophages via the NOS pathway. In this study, a new family of l-nitroarginine (NOArg) based polyester amide (NOArg-PEA) and NOArg-Arg PEA copolymers (co-PEA) were designed and synthesized with different composition ratios. The NOArg-PEA and NOArg-Arg co-PEAs are biodegradable (more than 50% degradation in vitro in 4 days at 37 °C), biocompatible and did not activate the resting macrophage immune response per se. When classically activated or alternatively activated macrophages (CAM/AAM) were incubated with NOArg-PEA and NOArg-Arg co-PEAs, the treatments decreased the NO production of CAM, increased the arginase activity in both CAM and AAM, increased TGF-β1 production of CAM to various degrees and had no significant effect on TNF-α production. Diabetic rat models were used to evaluate the efficacy of NOArg-PEA and NOArg-Arg co-PEAs on wound healing. Diabetic rats treated with 2-NOArg-4 PEA, 2-NOArg-4-Arg-4 20/80, and 2-NOArg-4-Arg-4 50/50 biomaterials achieved 40%-80% faster-wound healing when compared with the control on day 7. The data from the histological and immunohistochemical analysis showed that the 2-NOArg-4-Arg-4 20/80 and 2-NOArg-4-Arg-4 50/50 treatments led to more AAM phenotypes (CD206) and arginase I production in wound tissue than the control during the first 7 days, i.e., suggesting pro-healing wound microenvironment with improved re-epithelialization of wound healing. A similar trend was retained until day 14. The 2-NOArg-4-Arg-4 20/80 and 2-NOArg-4-Arg-4 50/50 treatments also increased the collagen deposition and angiogenesis in the healing wound between day 7 and day 14. Both in vitro and in vivo data of this study showed that this new family of NOArg-Arg co-PEA biomaterials have the potential as viable alternatives for treating impaired wound healing, such as diabetic or other types of chronic wounds. STATEMENT OF SIGNIFICANCE: Diabetic or other chronic wounds is usually associated with an overproduction of NO and pro-inflammatory signals by macrophages. Arginine supplement or NOS inhibitors administration failed to achieve an expected improved wound healing because of the dynamic complexity of arginine catabolism, the difficulty in transition from pro-inflammatory to pro-healing, and the short-term efficacy. We designed and synthesized a new family of water-soluble and degradable nitroarginine-arginine polyester amides to rebalance NOS/arginase metabolism pathways of macrophages. They showed tunable immunomodulating properties in vitro. The in vivo studies were performed to evaluate their efficacy in accelerating the healing. These new biomaterials have the potential as viable alternatives for treating impaired wound healing. The general audience of Acta Biomaterialia should be interested in these findings.

Reference limits for hepatic bile duct-to-arteriole and bile duct-to-portal tract ratios in healthy cats

OBJECTIVE To establish reference limits for hepatic bile duct-to-arteriole ratio (BD:A) and bile duct-to-portal tract ratio (BD:PT) in healthy cats and assess whether these parameters could be used to support a diagnosis of biliary ductopenia in cats. SAMPLE Hepatic biopsy samples from healthy cats (n = 20) and cats with ductopenia (2). PROCEDURES Hepatic biopsy samples from healthy cats were used to count the number of bile ducts and hepatic arterioles in 20 portal tracts for each cat. Mean BD:A and mean BD:PT for each cat were calculated, and these values were used to determine reference limits for mean BD:A and mean BD:PT. Results of histologic evaluation, including immunohistochemical staining in some instances, were compared for healthy cats versus cats with ductopenia. RESULTS Of the 400 portal tracts from healthy cats, 382 (95.5%) and 396 (99.0%) had BD:A and BD:PT, respectively, ≥ 1.0, with less variability in BD:A. Mean BD:A and BD:PT were markedly lower in both cats with ductopenia, compared with values for healthy cats. However, only mean BD:A for cats with ductopenia was below the reference limit of 0.59. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that systematic evaluation of BD:A, with a lower reference limit of 0.59 to define biliary ductopenia in cats, may be a discrete and easily applied morphometric tool to enhance detection of ductopenia in cats. However, application of this ratio required evaluation of ≥ 20 portal tracts with cross-sectioned portal elements to determine a mean BD:A value.

Nonarticular osseous cyst-like lesions of the intermedioradial carpal bone may be incidental magnetic resonance imaging findings in dogs

As magnetic resonance imaging (MRI) becomes more readily available and more frequently utilized in the assessment of canine carpal lameness, both normal variations and early pathologic conditions must be recognized to optimize patient care and provide accurate diagnosis. On cross sectional studies of the canine carpus, cyst-like lesions have been detected at the dorsolateral aspect of the intermedioradial carpal bone. The cross-sectional imaging and histologic properties of these lesions have not been described. The purpose of this observational study is to evaluate the MRI and histologic features of these cyst-like lesions in a cohort of clinically sound dogs. It was hypothesized that the lesions would show features similar to intraosseous ganglion cysts of the human wrist. Twenty-five cadaveric canine carpi were obtained and a total of 13 lesions were detected on MRI. Based on MRI, six carpi with lesions of varying size and one normal carpus were submitted for histological evaluation. Five of the abnormal carpi had nonarticular cyst-like lesions; one specimen with a positive magnetic resonance image for a cyst-like lesion had no cyst-like lesion on histology. Conspicuity of a medium-size lesion as evaluated on radiographs was poor. Given the presence of these nonarticular cyst-like lesions in a population of clinically sound patients, their clinical importance is uncertain. The development of these lesions may relate to altered mechanics or genetic predispositions, requiring additional study.

Extended low-resolution structure of a Leptospira antigen offers high bactericidal antibody accessibility amenable to vaccine design

Pathogens rely on proteins embedded on their surface to perform tasks essential for host infection. These obligatory structures exposed to the host immune system provide important targets for rational vaccine design. Here, we use a systematically designed series of multi-domain constructs in combination with small angle X-ray scattering (SAXS) to determine the structure of the main immunoreactive region from a major antigen from Leptospira interrogans, LigB. An anti-LigB monoclonal antibody library exhibits cell binding and bactericidal activity with extensive domain coverage complementing the elongated architecture observed in the SAXS structure. Combining antigenic motifs in a single-domain chimeric immunoglobulin-like fold generated a vaccine that greatly enhances leptospiral protection over vaccination with single parent domains. Our study demonstrates how understanding an antigen's structure and antibody accessible surfaces can guide the design and engineering of improved recombinant antigen-based vaccines.