Congenital malformations caused by Akabane virus in porcine fetuses in southern Japan.

Akabane virus (AKAV) is known as a major teratogenic agent of ruminant fetuses. In this study, we investigated the relationship between porcine abnormal deliveries and AKAV by serology, pathology, and virology investigations using specimens from 16 stillborn fetuses delivered in southern Japan between 2013 and 2015. The major clinical manifestations in stillborn fetuses were hydranencephaly, arthrogryposis, spinal curvature, and both skeletal muscle and subcutaneous edema. Histologic examination of the specimens identified atrophy of skeletal muscle fibers accompanied by adipose replacement. Nonsuppurative encephalomyelitis and decreased neuronal density in the ventral horn of the spinal cord were shown in two separate fetuses, respectively. Neutralizing antibody titers to AKAV were detected in most of the tested fetuses (13/16). The AKAV sequences detected in the affected fetuses in 2013 and 2015 were highly identical and closely related to Japanese AKAV isolates which were isolated in 2013 and sorted into genogroup I of AKAV. Immunohistochemistry visualized AKAV antigens in the neuronal cells of the central nervous system of the fetuses. These findings indicate that AKAV was involved in the birth of abnormal piglets at the affected farm. The clinical manifestations and histopathological features in the stillborn fetuses were very similar to those in ruminant neonates affected by AKAV. To avoid misdiagnosis and to evaluate the precise impact of AKAV on pig reproduction, AKAV should be considered in differential diagnoses of reproductive failures in pigs.

Variations in the morphology of Rhizomucor pusillus in granulomatous lesions of a Magellanic penguin (Spheniscus magellanicus).

This report presents a new case of mucormycosis encountered in penguin characterized by morphological variation of hyphae and presence of sporangia with numerous sporangiospores. A 4.5-year-old Magellanic penguin (Spheniscus magellanicus) died after exhibiting anorexia, poor nutritional condition and dyspnea. Multiple nodular lesions were observed in the thoracic and abdominal regions. Histopathologically, hyphae of various sizes were seen in the lungs, air sac and nodular lesions. Myriad sporangiospores and several sporangia were observed in/around the bronchi or parabronchi. The very narrow and short hyphae in the nodules were not consistent with the characteristics of Mucorales. However, for most hyphae, including those in the nodules, sporangiospores and sporangia, immunohistochemistry revealed Mucorales-positive reactions. In addition, these fungi were identified as Rhizomucor pusillus by gene analysis.

Ultrastructural characteristics and molecular identification of Entamoeba suis isolated from pigs with hemorrhagic colitis: implications for pathogenicity.

Protozoan parasites of the genus Entamoeba infect many classes of vertebrates and are primarily classified based on morphological criteria. To date, only a few species have been proven to cause disease. Here, we examined the pathology of infected pigs with hemorrhage and detected Entamoeba parasites. Isolates were characterized genetically and ultrastructurally to identify the species. Histopathologically, bleeding and thrombus formation were seen only in the large intestine mucosa, where a large number of trophozoites or some Entamoeba cysts were observed around breakdowns in the lamina propria. No screw-shaped bacteria were detected in the lesions, and no pathogenic bacteria such as Brachyspira spp. were detected in fecal cultures. Interestingly, electron microscopy revealed that the parasites possessed mitochondrial organelles, unlike other Entamoeba spp. The isolates were identified as Entamoeba suis by PCR analysis and sequencing of the small subunit ribosomal RNA (SSU rRNA) gene. In phylogenetic analyses based on the actin gene, the E. suis isolate formed a cluster with Entamoeba histolytica and Entamoeba invadens, as well as with other parasites of the Amoebidae. Whether the pathogenicity of the E. suis isolate is affected by the severity of infection or host health status remains unclear; however, our results suggest that E. suis could cause or exacerbate clinical symptoms such as hemorrhagic colitis or diarrhea.

Establishment of a quantitative bovine CXCL8 sandwich ELISA with newly developed monoclonal antibodies.

Three IgG class anti-bovine CXCL8 (bCXCL8) monoclonal antibody (mAb)-secreting hybridomas, SH8-8D7, SH8-12A5 and SH8-2A1, were developed. SH8-8D7 was IgG2a, and SH8-12A5 and SH8-2A1 were IgG1. All three mAbs detected recombinant bCXCL8 (rbCXCL8) by immunoprecipitation and Western blotting. SH8-2A1 could neutralise the chemotactic activity of rbCXCL8 towards neutrophils. The quantitative bCXCL8 ELISA was constituted by the combination of SH8-12A5 and biotin-SH8-2A1. The detection range was 20-1000  pg/mL. A sandwich ELISA was used to measure native bCXCL8 derived from the supernatant of cultured bovine peripheral blood mononuclear cells stimulated with ConA, LPS or PHA. Furthermore, SH8-2A1 could detect bCXCL8 in formalin-fixed, paraffin-embedded, pneumonic calf tissues. These findings indicate that the newly developed anti-bCXCL8 mAbs could contribute to research on bovine inflammatory responses and immunology.