Mutated influenza A virus exhibiting reduced susceptibility to baloxavir marboxil from an experimentally infected horse.

Baloxavir marboxil (BXM), an inhibitor of the cap-dependent endonuclease of the influenza virus polymerase acidic protein (PA), exerts an antiviral effect against influenza A virus. It has been available in Japan since March 2018. This study evaluated the antiviral efficacy of BXM against equine influenza A virus (EIV) by an experimental challenge study using horses.

Risk factors for exertional heat illness in Thoroughbred racehorses in flat races in Japan (2005-2016).

Background: Exertional heat illness (EHI) is recognised in horses, but few reports have investigated its risk factors.

Objectives: To identify risk factors for EHI in racehorses participating in flat races in Japan.

Study Design: Descriptive epidemiology and retrospective unmatched case-control study.

Epizootiological investigation of equine herpesvirus type 1 infection among Japanese racehorses before and after the replacement of an inactivated vaccine with a modified live vaccine.

Background: Equine herpesvirus type 1 (EHV-1) infection is a major cause of pyrexias in winter among Japanese racehorses. In 2014-2015, the Japan Racing Association (JRA) changed the EHV-1 vaccine from an inactivated vaccine to a live vaccine (both produced by Nisseiken). To evaluate the effect of changing the vaccines, the capacities of these vaccines to induce virus-neutralizing (VN) antibodies were compared, and an epizootiological investigation of EHV-1 was performed at the JRA Ritto Training Center during epizootic periods from 2010-2011 to 2016-2017.

Two Cases of Equine Multinodular Pulmonary Fibrosis in Japan.

Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with equine herpesvirus type 5 (EHV-5). This disease has been reported in North and South America, Europe and Oceania but not, to our knowledge, in horses in Japan. We diagnosed EMPF in two Thoroughbred horses in Japan on the basis of gross and histopathological findings.

Actinobacillus species isolated from Japanese Thoroughbred racehorses in the last two decades.

Actinobacillus species are known to be pathogenic to horses. To clarify etiological agents of actinobacillosis in Japanese adult horses, 27 isolates from Japanese Thoroughbred racehorses putatively identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry as Actinobacillus were further identified by PCR of the A. equuli toxin gene, by CAMP test, and by 16S rRNA sequencing analysis.

A retrospective comparison of induction with thiopental/guaifenesin and propofol/ketamine in Thoroughbred racehorses anesthetized with sevoflurane and medetomidine during arthroscopic surgery.

This study compares clinical characteristics between induction with thiopental/guaifenesin and propofol/ketamine in Thoroughbred racehorses anesthetized with sevoflurane and medetomidine. Clinical records of 214 horses that underwent arthroscopic surgery between 2015 and 2016 were retrospectively retrieved. Horses were premedicated with medetomidine and midazolam to sedate at the adequate level for smooth induction, and then induced with either thiopental (4.

Prevalence of post-race exertional heat illness in Thoroughbred racehorses and climate conditions at racecourses in Japan.

Despite growing recognition of post-race exertional heat illness (EHI) in the horse racing industry, reports on its prevalence are limited. The purpose of this study was to investigate the prevalence of post-race EHI and climate conditions at racecourses in Japan. The overall prevalence of EHI from 1999 to 2018 was 0.

Serological responses of Australian horses using a commercial duplex indirect ELISA following vaccination against strangles.

Objective: To determine the nature of serological responses in Australian horses using a commercial duplex indirect ELISA (iELISA) following vaccination against strangles.

Design: A group (n = 19) of client-owned horses from five properties were recruited to receive a primary course of a Streptococcus equi subsp. equi (S.

A single amino acid change in hemagglutinin reduces the cross-reactivity of antiserum against an equine influenza vaccine strain.

Equine influenza virus is an important pathogen for the horse industry because of its economic impact, and vaccination is a key control measure. Our previous work suggested that a mutation at position 144 in the hemagglutinin of Florida sublineage clade 2 viruses reduces the cross-neutralizing activity of antiserum against a former vaccine strain. To confirm this suggestion, here, we generated viruses by reverse genetics.

Heritability estimates of the position and number of facial hair whorls in Thoroughbred horses.

Objective: According to oral traditions of horse caretakers and trainers, the differences in the position and number of facial hair whorls may be associated with temperamental traits. Elucidating genetic background of facial hair whorls and its relationship to temperamental traits may promote more efficient breeding and maintenance of racehorses. In this study, we estimated heritabilities of the position and number of facial hair whorls in Japanese Thoroughbred horses.

Development of an enzyme-linked immunosorbent assay for Getah virus infection in horses using recombinant E2 protein as an antigen.

Getah virus causes fever, skin eruptions, and limb edema in horses. For a high-throughput and time-saving method for serodiagnosis, we explored immunogenic antigens of Getah virus, and established an enzyme-linked immunosorbent assay (ELISA) using a recombinant protein. Western blot analysis using sera from infected horses showed strong reaction with viral antigens around 46 kDa corresponding to E1 or E2 glycoproteins.

Loop-mediated isothermal amplification-fluorescent loop primer assay for the genotyping of a single nucleotide polymorphism at position 2254 in the viral DNA polymerase gene of equid alphaherpesvirus 1.

We developed a loop-mediated isothermal amplification (LAMP)-fluorescent loop primer (FLP) assay for genotyping the A/G single nucleotide polymorphism (SNP) in the viral DNA polymerase gene of species (EHV-1), which is associated with the neuropathogenic potential of this virus. In addition to the use of regular LAMP primers to amplify the target region, a 5'-FAM-labeled backward loop primer (FLB) and 3'-dabcyl-labeled quencher probe (QP) were designed for annealing curve analysis of the amplification product. The QP, which contacts the FLB, is located at the SNP site and has the A allele.

Molecular analyses of G3A/G3B and G14 equine group A rotaviruses detected between 2012 and 2018 in Japan.

Equine group A rotaviruses (RVAs) cause diarrhoea in foals. We investigated the G genotypes of 360 RVA-positive samples obtained from diarrhoeic foals between 2012 and 2018 in the Hidaka district of Hokkaido, Japan, through sequence analysis of VP7. All samples were classified into genotypes G3A, G3B and G14.

A novel selective medium for the isolation of Burkholderia mallei from equine specimens.

Background: Burkholderia mallei is a Gram-negative bacterium that causes glanders, a zoonotic disease, especially in equine populations (e.g. horses, donkeys, and mules).

Genetic analysis of Streptococcus equi subsp. equi isolated from horses imported into Japan.

Strangles is a commonly diagnosed and important infectious disease of equids worldwide, caused by Streptococcus equi subsp. equi. We determined the SeM genotypes of S.

Application of Novel Sialoglyco Particulates Enhances the Detection Sensitivity of the Equine Influenza Virus by Real-Time Reverse Transcriptase Polymerase Chain Reaction.

Sialoglyco particulates carrying an -glycolylneuraminyl-α-(2 → 3)--acetyllactosamine (Neu5Gcα2,3LacNAc) residue that displays a high level of affinity for the equine influenza virus (EIV) were generated using sialoglycopolypeptide and hexyl-containing hybrid silica particulates. The particulates were spherical with a diameter of approximately 950 nm and found to have good dispersibility in aqueous solution. Interaction between the sialoglyco particulates and the EIV was investigated by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) of the EIV genome captured on the particulates.

Bone marrow oedema-type signal in the proximal phalanx of Thoroughbred racehorses.

This study focused on 8 Thoroughbred racehorses showing bone marrow oedema-type signal in the proximal sagittal groove of the proximal phalanx, with the aim of understanding its clinical significance. Standing magnetic resonance imaging played an important role in assessing osseous abnormalities that were not radiographically identifiable. Further, a histopathological result from one of the cases showed there was oedema surrounding adipose tissues with increase in density of trabecular scaffolding.

Rapid and sensitive detection of elephant endotheliotropic herpesvirus 1 (EEHV1) in blood by loop-mediated isothermal amplification (LAMP).

Elephant endotheliotropic herpesvirus type 1 (EEHV1) is the most important causative agent of an acute fatal hemorrhagic disease in Asian elephants (Elephas maximus). We employed loop-mediated isothermal amplification (LAMP) to develop a rapid and simple detection method for EEHV1 in blood. When used to test 21 clinical samples collected in Japan, the EEHV1 assay correctly identified one positive and 20 negative clinical samples.

Evaluation of two enzyme-linked immunosorbent assays for the detection of antibodies against equine arteritis virus.

In order to establish an efficient system for serological diagnosis of equine viral arteritis in Japan, we compared enzyme-linked immunosorbent assays (ELISAs) provided by two manufacturers (Nisseiken Co., Ltd., Tokyo, Japan, and VMRD Inc.

Clinical effects of constant rate infusions of medetomidine-propofol combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery.

Background: The aim of the present study was to evaluate clinical efficacy of constant rate infusions (CRIs) of medetomidine-propofol combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery. Thirty horses were sedated intravenously (IV) with medetomidine (6.0 μg/kg) and midazolam (0.

Cross-reactivity of latex agglutination assay complicates the identification of Burkholderia pseudomallei from soil.

The monoclonal antibody-based latex agglutination tests targeting a high molecular weight exopolysaccharide antigen of Burkholderia pseudomallei are commercially available. The tests are primarily used in routine diagnosis of melioidosis in major hospitals in Thailand and some endemic countries. Being a rapid test, this technique was employed as a presumptive test to identify colonies of B.

Evaluating continuous blood coagulopathy in assessing the severity of acute colitis in Thoroughbred racehorses.

Although severe blood coagulopathy in horses with acute colitis causes multiple organ failure, which may be fatal, few studies have focused on the correlation between the fluctuations of coagulation parameters and severity of colitis. In this study, we evaluated the fluctuations of coagulation parameters in 14 Thoroughbred racehorses with acute colitis for 5 days from the day of hospitalization and compared them between 5 survivors and 9 non-survivors. Noteworthy features in the non-survivors were that antithrombin activity and fibrin degradation products continuously decreased and increased, respectively, for 4 days or more and that thrombin-antithrombin complexes increased in the last 2 days before death.

Comparison of oxidative stress under different propofol administration protocols in Thoroughbred racehorses by bOS and bAP assessment.

It is desirable to reduce surgery-induced oxidative stress (OS) because it can cause immune suppression and delayed wound healing. Propofol is known to have antioxidant potential and to reduce OS in humans, but there have been no studies of this issue in horses. This study was conducted to evaluate OS under three different propofol administration protocols in Thoroughbred racehorses undergoing arthroscopic surgery with sevoflurane anesthesia.

Clinical evaluation of constant rate infusion of alfaxalone-medetomidine combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery.

Background: Alfaxalone has a number of pharmacological properties which are desirable for constant rate infusion (CRI). Previously, the co-administration of alfaxalone and medetomidine is shown to be suitable for short-term anesthesia in horses. However, the use of alfaxalone-medetomidine CRI with inhalational anesthesia under surgical procedures have not been investigated in clinical cases.