Edwardsiella ictaluri was consistently isolated from the spleens, livers, and head kidneys of diseased Nile tilapia Oreochromis niloticus from a farm experiencing mortality events in several culture ponds. We describe the first published outbreak of E. ictaluri-induced edwardsiellosis in Nile tilapia. Pure cultures of the isolated bacteria were characterized both biochemically and molecularly. Biochemical analysis was performed using the API-20E and RapID One systems, and antimicrobial susceptibility was determined by the broth microdilution method. Molecular analysis involved sequencing of the 16S rRNA gene, species-specific real-time polymerase chain reaction (PCR), and PCR-mediated genomic fingerprinting (rep-PCR). Pairwise sequence analysis of the 16S rRNA gene identified the case isolates to be a 100% match to E. ictaluri cultured from channel catfish in the southeastern United States. However, rep-PCR analysis identified the case isolates to be genetically different from representative strains isolated from disease outbreaks in cultured channel catfish in Mississippi. Infectivity challenges (intraperitoneal injection and immersion) demonstrated that a representative E. ictaluri strain isolated from tilapia was pathogenic to naive tilapia, reproducing clinical signs and mortality, thereby establishing Koch's postulates.

Abstract. Members of the genus Francisella (viz., F. noatunensis subsp. orientalis [Fno] and F. noatunensis subsp. noatunensis) have been described as causative agents of chronic granulomatous and pyogranulomatous lesions in wild and cultured fish species. In the present study, 68 archived formalin-fixed, paraffin-embedded (FFPE) tissues from several fish species, collected at different geographical locations from 2000 to 2011, were analyzed using a real-time polymerase chain reaction assay for the detection of the Fno intracellular growth loci C (iglC) gene and by immunohistochemistry for the demonstration of Fno antigens. The results revealed a high correlation between these 2 diagnostic techniques validating their use for the diagnosis of Fno infection in archived FFPE tissues and confirming the presence of Fno in fish species from the Caribbean, Hawaii, and continental North and South America in the early years of the present century.

An unusual case of osteomyelitis caused by Nocardia cyriacigeorgica infection and resulting in mandibular osteomyelitis and cellulitis (lumpy jaw) is described in a young cat. A 1-cm hard nodular mass was an incidental finding in the right mandible of a 14-month-old cat during routine physical examination. The lesion was fast growing, reaching up to 6 cm in its largest dimension over a 5-week period. A core biopsy of the affected mandible revealed foci of osteolysis, woven bone formation, and a few large clusters of filamentous bacteria surrounded by fine eosinophilic amorphous material bordered by neutrophils, plasma cells, macrophages, and occasional multinucleated giant cells. Pure cultures of acid-fast variable, Gram-positive filamentous bacteria were recovered on blood and chocolate agar plates at 48-hr postinoculation. On amplification and sequencing of the 16S ribosomal RNA and 65-kDa heat shock protein genes, the microorganisms were identified as N. cyriacigeorgica, within the actinomycetes.

Ultrasonography is commonly used to examine testes as part of a breeding soundness examination in sheep, especially, in cases of infertility or when gross testicular abnormalities are present.A descriptive, prospective, prevalence study was conducted to characterize the ultrasonographic, histopathologic, and spermatozoal morphology abnormalities present in a group of yearling tropic hair rams on the island of St. Kitts. Hyperechoic and shadowing abnormalities increased over a 6 month study period. Hyperechoic abnormalities were present in one or both testes in 89% (25/28) of yearling rams and 71% (40/56) of testes at castration. Shadowing abnormalities were present in one or both testes in 46% (13/28) of rams and 34% (19/56) of testes at castration. Shadowing was present more with moderate and severe hyperechoic abnormalities, with few testes in the mild category having any shadowing. As hyperechoic and shadowing abnormalities increased in severity, so did the severity of microscopic lesions including increased interstitial cellularity/fibrosis, interstitial mineralization, seminiferous tubules mineralization (hyperechoic only), and chronic lymphoplasmacytic orchitis. There were no spermatozoal morphologic abnormalities other than an increase in distal cytoplasmic droplets. The study findings detail a pathologic event in this group of yearling rams that has an unknown etiology. Potential causes may include scrotal insulation, trauma, infectious causes, immunity alterations, nutritional imbalances, and ingestion of a toxin.Further studies are required to elucidate the causative agent. K E Y W O R D Sdegeneration, histology, ovine, testicular ultrasound 338

Neuropathology is a challenging subject for most medical students. Delivering a gamified learning tool on this topic may motivate students and increase knowledge in the discipline. We report the development of such a tool in iBook format for the systemic pathology course delivered at Ross University School of Veterinary Medicine. Composed of 10 chapters (cases), this Neuropathology iBook (NP-iB) reviews basic clinical manifestations, neuropathology, and pathogenesis of common non-neoplastic conditions that cause brain disease in domestic animals. The goal of each chapter is to reach a diagnosis by interactively answering specific questions after reviewing relevant medical history, clinical pathology, and autopsy findings. Our hypothesis: the NP-iB improves students’ ability to recognize these diseases, reflected in higher test scores. Using a post-test only control group design, data were gathered from all students enrolled in the course in two different semesters, fall 2017 and spring 2018 ( n = 300). NP-iB users ( n = 51, 17%) and usage time were identified by answers to multiple-choice questions embedded in the course assessments. Ninety percent of users had a positive perception although no statistically significant differences were found in median test scores between users and non-users. Statistically significant test score differences were found across how much time students used the NP-iB ( p = .005); the lowest test score median values were found for neuropathology questions not related to the NP-iB, in students who used it for more than 3 hours. Unexpectedly, a low number of students preferred this digital learning tool, and its use did not improve their learning outcomes.