Manabu Nemoto

Interspecies transmission of equine influenza virus (H3N8) to dogs by close contact with experimentally infected horses.

In horse populations, influenza A virus subtype H3N8 (equine influenza virus, EIV) is a very important pathogen that leads to acute respiratory disease. Recently, EIV has emerged in dogs, and has become widespread among the canine population in the United States. The interspecies transmission route had thus far remained unclear. Here, we tested whether the interspecies transmission of EIV to dogs could occur as a result of close contact with experimentally EIV-infected horses. Three pairs consisting of an EIV-infected horse and a healthy dog were kept together in individual stalls for 15 consecutive days. A subsequent hemagglutination inhibition test revealed that all three dogs exhibited seroconversion. Moreover, two of the three dogs exhibited virus shedding. However, the dogs exhibited no clinical signs throughout the course of the study. These data suggest that the interspecies transmission of EIV to dogs could occur as a result of close contact with EIV-infected horses without clinical symptoms. Although the interspecies transmission of EIV is unlikely to become an immediate threat to canine hygiene, close contact between EIV-infected horses and dogs should be avoided during an EI epidemic.

Case of type 1 diabetes associated with less-dose nivolumab therapy in a melanoma patient.

gates of foamy histiocytes in the dermis and verrucous acanthosis. Regarding its pathogenesis, it is thought that the epithelial damage and degeneration cause the release of lipid materials and subsequent phagocytosis by macrophages in the dermis, followed by the accumulation of numerous foamy cells and the proliferation of reactive keratinocytes. In addition to human papillomavirus infection, localized lymphatic stasis caused by congenital or acquired factors (e.g. trauma, skin grafting, radiation or chronic inflammatory dermatosis) has been described as a predisposing factor for the development of VX. The direct pathogenic association of VX with lymphedema remains unclear; however, lymphatic stasis, which is the obstructive stasis of proteinor lipid-rich interstitial fluid, causes susceptibility to various external stimuli, such as bacterial infection and friction as well as a prolonged inflammation, all of which can be predisposing factors for the development of VX. In this case, the patient suffered from a long-standing severe lymphedema resistant to the lymphatic venous anastomosis, accompanied by acquired LC, which is a relatively rare sequela. Additionally, the skin of vulvar region had been repeatedly affected by both infection and friction, which might have facilitated the prolipidogenic degeneration of keratinocytes and resulted in the formation of a VX. CONFLICT OF INTEREST: None declared.

Prediction of the Pathogens That Are the Cause of Pneumonia by the Battlefield Hypothesis

Commensal organisms are frequent causes of pneumonia. However, the detection of these organisms in the airway does not mean that they are the causative pathogens; they may exist merely as colonizers. In up to 50% cases of pneumonia, the causative pathogens remain unidentified, thereby hampering targeting therapies. In speculating on the role of a commensal organism in pneumonia, we devised the battlefield hypothesis. In the “pneumonia battlefield,” the organism-to-human cell number ratio may be an index for the pathogenic role of the organism. Using real-time PCR reactions for sputum samples, we tested whether the hypothesis predicts the results of bacteriological clinical tests for 4 representative commensal organisms: Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis. The cutoff value for the organism-to-human cell number ratio, above which the pathogenic role of the organism was suspected, was set up for each organism using 224 sputum samples. The validity of the cutoff value was then tested in a prospective study that included 153 samples; the samples were classified into 3 groups, and each group contained 93%, 7%, and 0% of the samples from pneumonia, in which the pathogenic role of Streptococcus pneumoniae was suggested by the clinical tests. The results for Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis were 100%, 0%, and 0%, respectively. The battlefield hypothesis enabled legitimate interpretation of the PCR results and predicted pneumonia in which the pathogenic role of the organism was suggested by the clinical test. The PCR reactions based on the battlefield hypothesis may help to promote targeted therapies for pneumonia. The prospective observatory study described in the current report had been registered to the University Hospital Medical Information Network (UMIN) registry before its initiation, where the UMIN is a registry approved by the International Committee of Medical Journal Editors (ICMJE). The UMIN registry number was UMIN000001118: A prospective study for the investigation of the validity of cutoff values established for the HIRA-TAN system (April 9, 2008).

The potential impact of a single amino‐acid substitution on the efficacy of equine influenza vaccines

REASONS FOR PERFORMING STUDY The protection induced by an equine influenza (EI) vaccine strain depends on its antigenic relatedness to the challenge virus. Although the World Organisation for Animal Health (OIE) recommend that both Florida sublineage clade 1 (Fc1) and clade 2 (Fc2) viruses should be included in EI vaccines, Japanese EI vaccines have not, thus far, been updated to include a Fc2 virus. OBJECTIVES To evaluate the efficacy of antibodies raised against Japanese EI vaccine strains in the neutralisation of recent Fc2 viruses. STUDY DESIGN Antigenic analysis. METHODS Virus neutralisation tests were performed using antisera from experimentally infected horses and from horses that had received a primary course of the currently available vaccines. RESULTS Antiserum raised against the Japanese EI vaccine strain, A/equine/La Plata/1993, exhibited poor cross-neutralising activity against the Fc2 viruses isolated recently in Ireland and the UK, which have the substitution of alanine to valine at position 144 in antigenic site A of the haemagglutinin gene. In contrast, the antiserum exhibited good cross-neutralising activity against the Fc2 viruses without the substitution. This finding was supported in experiments with antisera collected from vaccinated horses. CONCLUSIONS This suggests that the efficacy of the Japanese EI vaccine for some of the recent Fc2 viruses is suboptimal and that vaccines should be updated in accordance with the OIE recommendations.

Efficacy of a single intravenous dose of the neuraminidase inhibitor peramivir in the treatment of equine influenza

Equine influenza A virus (EIV) of the H3N8 subtype is an important pathogen causing acute respiratory disease in horses. Peramivir is a selective inhibitor of the influenza virus neuraminidase (NA). The characteristics of peramivir are not only its capacity for parenteral administration, but also its strong affinity for NA and slow off-rate from the NA-peramivir complex, suggesting that it could lead to a prolonged inhibitory effect and thus allow a lower dosing frequency. The aims of this study were to evaluate the inhibitory efficacy of peramivir against the NA activities of EIV in vitro and the treatment efficacy of a single intravenous dose of peramivir in horses experimentally infected with EIV. Peramivir inhibited the activities of NA from the seven contemporary EIV strains in vitro, with 50% inhibitory concentrations ranging from 0.10 to 0.20 nmol/L. Horses treated with a single IV dose of peramivir (3,000 mg/600 mL/animal, 7.8-9.3mg/kg of bodyweight) showed significantly milder clinical signs (pyrexia, nasal discharge and cough) with a shorter duration than control horses injected with normal saline. Moreover, the mean duration of virus shedding for the horses treated with peramivir was significantly shorter than for the control horses. These findings suggested that a single IV administration of peramivir had good potential for the treatment of equine influenza, and may help to limit the spread of the disease in the horse population.

Development and evaluation of a reverse transcription loop-mediated isothermal amplification assay for H3N8 equine influenza virus.

Reverse transcription loop-mediated isothermal amplification (RT-LAMP) was applied to the detection of equine influenza virus (EIV). Because equine influenza is caused currently by EIV of the H3H8 subtype, the RT-LAMP primer set was designed to target the hemagglutinin gene of this subtype. The detection limit of the RT-LAMP assay was a virus dilution of 10(-5); which was 10(3) times more sensitive than the Espline Influenza A&B-N test and 10 times more sensitive than a reverse transcription polymerase chain reaction (RT-PCR) assay. The specificity of the RT-LAMP assay was examined by using several equine pathogens and nasal swabs collected from horses with fever in 2010 after EIV was eradicated in Japan. No cross-reactions were observed. Using 100 nasal swabs collected from horses with fever during an EIV outbreak in 2007, the RT-LAMP assay detected EIV in 52 samples, whereas the Espline test and the RT-PCR assay detected EIV in only 17 and 41 samples, respectively. These results indicate that the RT-LAMP assay is specific for EIV and more sensitive than the Espline test and the RT-PCR assay. Because it provides high sensitivity and ease of manipulation without the need for a thermal cycler or gel electrophoresis, the RT-LAMP assay should be applicable for laboratory diagnosis of EIV.

Getah Virus Infection among Racehorses, Japan, 2014.

An outbreak of Getah virus infection occurred among racehorses in Japan during September and October 2014. Of 49 febrile horses tested by reverse transcription PCR, 25 were positive for Getah virus. Viruses detected in 2014 were phylogenetically different from the virus isolated in Japan in 1978.

No evidence of horizontal infection in horses kept in close contact with dogs experimentally infected with canine influenza A virus (H3N8)

BackgroundSince equine influenza A virus (H3N8) was transmitted to dogs in the United States in 2004, the causative virus, which is called canine influenza A virus (CIV), has become widespread in dogs. To date, it has remained unclear whether or not CIV-infected dogs could transmit CIV to horses. To address this, we tested whether or not close contact between horses and dogs experimentally infected with CIV would result in its interspecies transmission.MethodsThree pairs of animals consisting of a dog inoculated with CIV (108.3 egg infectious dose50/dog) and a healthy horse were kept together in individual stalls for 15 consecutive days. During the study, all the dogs and horses were clinically observed. Virus titres in nasal swab extracts and serological responses were also evaluated. In addition, all the animals were subjected to a gross pathological examination after euthanasia.ResultsAll three dogs inoculated with CIV exhibited clinical signs including, pyrexia, cough, nasal discharge, virus shedding and seroconversion. Gross pathology revealed lung consolidations in all the dogs, and Streptococcus equi subsp. zooepidemicus was isolated from the lesions. Meanwhile, none of the paired horses showed any clinical signs, virus shedding or seroconversion. Moreover, gross pathology revealed no lesions in the respiratory tracts including the lungs of the horses.ConclusionsThese findings may indicate that a single dog infected with CIV is not sufficient to constitute a source of CIV infection in horses.

Antibody response in vaccinated pregnant mares to recent G3BP[12] and G14P[12] equine rotaviruses

BackgroundBoth the G3P[12] and the G14P[12] type of equine group A rotavirus (RVA) have recently become predominant in many countries, including Japan. G3 types are classified further into G3A and G3B. The G3A viruses have been circulating in Europe, Australia, and Argentina, and the G3B viruses have been circulating in Japan. However, only an inactivated vaccine containing a single G3BP[12] strain is commercially available in Japan. To assess the efficacy of the current vaccine against recently circulating equine RVA strains, we examined antibody responses in pregnant mares to recent G3BP[12] and G14P[12] strains by virus neutralization test.FindingsAfter vaccination in five pregnant mares, the geometric mean serum titers of virus-neutralizing antibody to recent G3BP[12] strains increased 5.3- to 7.0-fold and were similar to that against homologous vaccine strain. Moreover, antibody titers to recent G14P[12] strains were also increased 3.0- to 3.5-fold.ConclusionsThese results suggest that inoculation of mares with the current vaccine should provide foals with virus-neutralizing antibodies against not only the G3BP[12] but also the G14P[12] RVA strain via the colostrum.

Rate of Antithrombotic Drug use and Clinical Outcomes According to CHADS2 Scores in Patients With an Initial Cardioembolic Stroke who had Nonvalvular Atrial Fibrillation

BACKGROUND This study investigated the relationship between CHADS2 scores and the rate of antithrombotic drug use and clinical outcomes in patients with an initial cardioembolic stroke who had nonvalvular atrial fibrillation (NVAF). METHODS In 234 patients (135 men and 99 women; mean age [± SD] 76 ± 11 years) with initial cardiogenic cerebral embolism with NVAF who were admitted to our hospital between April 2007 and March 2011, the CHADS2 score, use of warfarin, and clinical outcomes were retrospectively investigated. RESULTS CHADS2 scores were as follows: 0 points, n = 21 (9%); 1 point, n = 72 (31%); 2 points, n = 92 (39%); 3 points, n = 47 (20%); and 4 points, n = 2 (1%). The overall warfarin use rate was low (14.1%; n = 33), and it was significantly (P = .023) lower for paroxysmal atrial fibrillation (8%) than for chronic atrial fibrillation (18.5%). The clinical outcomes evaluated by the modified Rankin Scale (mRS) score after 3 months were: CHADS2 score 0 points, mRS 0 to 2 (81%) and 3 to 6 (19%); 1 point, mRS 0 to 2 (46%) and 3 to 6 (54%); 2 points, mRS 0 to 2 (46%) and 3 to 6 (54%); and ≥ 3 points, mRS 0 to 2 (29%) and 3 to 6 (71%). The clinical outcome worsened as the CHADS2 score increased (P = .002). Logistic regression analysis revealed that being ≥ 75 years of age and having a high National Institutes of Health Stroke Scale (NIHSS) score on admission were related to a poor outcome (P < .001). CONCLUSIONS The overall warfarin use rate was low in initial cardioembolic stroke patients with NVAF. Clinical outcomes deteriorated with increases in the CHADS2 score, age ≥ 75 years, and NIHSS score on admission were related to a poor clinical outcome.