Gjelleinfeksjoner, gjellepatologi og gjellerelatert dødlighet hos oppdrettslaks

Last year (2021) 54 million Atlantic salmon died at Norwegian food producing sea sites. This constitutes a loss of 15,5% of the fish that were transferred to sea. Gill diseases are among the health issues that causes considerable mortality, economic loss, and reduced fish welfare in salmonid mariculture. The overall aim of the Ph.D. work was to investigate the impact and interactions of selected microorganisms, environmental and managerial factors on gill health of farmed Atlantic salmon. To determine if variation in pathogen prevalence and load, and zoo- and phytoplankton levels had an impact on gill health we performed a prospective cohort study. Groups of Atlantic salmon in Western Norway were followed with repeated sampling and data collection from the hatchery phase and throughout the 1st year at sea. A secondary goal was to describe the temporal development of selected gill infections. Neoparamoeba perurans appeared to be the most important cause of gill pathology in the study cohorts. No consistent covariation and no or weak associations were observed between the extent of gill pathology and prevalence or load of SGPV, Ca. B. cysticola and D. lepeophtherii. The only exception was an association between epithelial necrosis/apoptosis and SGPV, and to a lesser extent Ca. B. cysticola. At sea, D. lepeophtherii and Ca. B. cysticola persistently infected all fish-groups, while N. perurans and SGPV infection showed a seasonal variation. There was no impact of zoo- and phytoplankton on gill health or overall mortality in our cohorts. Co-infection with three or more putative gill pathogens was common across all sites. To determine if in situ net cleaning, thermal and mechanical delousing had an impact on gill health, we performed three separate historical control field trials. Exposure to biofouling debris during a single in situ net cleaning event of moderately fouled net pens was associated with an increase in the number of salmon with thrombi in the gills. There was an increase in vascular and hyperplastic gill lesions observed post-treatment after a single thermal or mechanical delousing treatment, though the overall percentage of gill tissue with pathology was generally low. An increased pathogen load of Ca. B. cysticola and differential expression of genes involved in pathways of cell stress, inflammation, repair, and proliferation was detected in the gill tissue after the thermal delousing event. Furthermore, there was an increase in the number of fish with microorganisms and lesions possibly associated with pathogens observed in the gill tissue after both treatments.Last year (2021) 54 million Atlantic salmon died at Norwegian food producing sea sites. This constitutes a loss of 15,5% of the fish that were transferred to sea. Gill diseases are among the health issues that causes considerable mortality, economic loss, and reduced fish welfare in salmonid mariculture. The overall aim of the Ph.D. work was to investigate the impact and interactions of selected microorganisms, environmental and managerial factors on gill health of farmed Atlantic salmon. To determine if variation in pathogen prevalence and load, and zoo- and phytoplankton levels had an impact on gill health we performed a prospective cohort study. Groups of Atlantic salmon in Western Norway were followed with repeated sampling and data collection from the hatchery phase and throughout the 1st year at sea. A secondary goal was to describe the temporal development of selected gill infections. Neoparamoeba perurans appeared to be the most important cause of gill pathology in the study cohorts. No consistent covariation and no or weak associations were observed between the extent of gill pathology and prevalence or load of SGPV, Ca. B. cysticola and D. lepeophtherii. The only exception was an association between epithelial necrosis/apoptosis and SGPV, and to a lesser extent Ca. B. cysticola. At sea, D. lepeophtherii and Ca. B. cysticola persistently infected all fish-groups, while N. perurans and SGPV infection showed a seasonal variation. There was no impact of zoo- and phytoplankton on gill health or overall mortality in our cohorts. Co-infection with three or more putative gill pathogens was common across all sites. To determine if in situ net cleaning, thermal and mechanical delousing had an impact on gill health, we performed three separate historical control field trials. Exposure to biofouling debris during a single in situ net cleaning event of moderately fouled net pens was associated with an increase in the number of salmon with thrombi in the gills. There was an increase in vascular and hyperplastic gill lesions observed post-treatment after a single thermal or mechanical delousing treatment, though the overall percentage of gill tissue with pathology was generally low. An increased pathogen load of Ca. B. cysticola and differential expression of genes involved in pathways of cell stress, inflammation, repair, and proliferation was detected in the gill tissue after the thermal delousing event. Furthermore, there was an increase in the number of fish with microorganisms and lesions possibly associated with pathogens observed in the gill tissue after both treatments

Uveal myxoid leiomyosarcoma in a horse

publishedVersio

Nasal and ocular amyloidosis in a 15-year-old horse

Localized nasal, conjunctival and corneal amyloidosis was diagnosed in a 15-year-old pony with nasal and conjunctival masses and severe dyspnoea. Multiple swellings had been evident in the nostrils for at least two years and had gradually increased in size before presentation due to dyspnoea and exercise intolerance. Surgical debulking of the masses was performed and histological examination revealed large amounts of extracellular, hyaline, eosinophilic, Congo red positive material in the lamina propria of the nasal mucosa. A tentative diagnosis of localized nasal amyloidosis was made. The treatment relieved the clinical signs, however, the nasal masses recurred and bilateral conjunctival, papillary masses developed. The horse was euthanized. Nodular nasal and papillary conjunctival masses consisting of rubbery, grey to yellow tissue were found at necropsy. At the limbus this tissue infiltrated and expanded the cornea. The masses consisted of amyloid and moderate infiltrates of T lymphocytes and B lymphocytes were present in the tissue. No predominance of either cell type was observed and no distinct neoplastic mass could be identified. Ultrastructural examination of the nasal mucosa and cornea confirmed the presence of abundant extracellular deposits of non-branching fibrils ranging from 9–11 nm in diameter consistent with amyloid. Immunohistochemistry of amyloid revealed no labelling for AA amyloid, and no peptides representing serum amyloid A (SAA) were detected by microscopic laser dissection and subsequent mass spectrometry. Peptides from immunoglobulin kappa-like light chains were detected and are suggestive of AL amyloidosis, however the results were inconclusive and a final identification of the amyloid protein could not be made. Nasal amyloidosis is a clinical entity of localized amyloid deposits in the horse. Localized amyloidosis involving the conjunctiva of the horse is previously described in only seven cases and the present case is the first case of combined, localized nasal and corneal amyloidosis in the horse. In several reported cases surgical excision has provided clinical improvement and return to normal levels of exercise, while medical treatment has had no effect. The present case however, shows that rapid recurrence and progression of nasal amyloidosis to involve ocular tissues can occur and lead to recurrent respiratory obstruction

Bilateral tympanokeratomas (cholesteatomas) with bilateral otitis media, unilateral otitis interna and acoustic neuritis in a dog

Abstract Background An aural cholesteatoma, more appropriately named tympanokeratoma, is an epidermoid cyst of the middle ear described in several species, including dogs, humans and Mongolian gerbils. The cyst lining consists of stratified, keratinizing squamous epithelium with central accumulation of a keratin debris. This case report describes vestibular ganglioneuritis and perineuritis in a dog with chronic otitis, bilateral tympanokeratomas and presumed extension of otic infection to the central nervous system. Case presentation An 11-year-old intact male Dalmatian dog with chronic bilateral otitis externa and sudden development of symptoms of vestibular disease was examined. Due to the dog’s old age the owner opted for euthanasia without any further examination or treatment and the dog was submitted for necropsy. Transection of the ears revealed grey soft material in the external ear canals and pearly white, dry material consistent with keratin in the tympanic bullae bilaterally. The brain and meninges were grossly unremarkable. Microscopical findings included bilateral otitis externa and media, unilateral otitis interna, ganglioneuritis and perineuritis of the spiral ganglion of the vestibulocochlear nerve and multifocal to coalescing, purulent meningitis. A keratinizing squamous epithelial layer continuous with the external acoustic meatus lined the middle ear compartments, consistent with bilateral tympanokeratomas. Focal bony erosion of the petrous portion of the temporal bone and squamous epithelium and Gram-positive bacterial cocci were evident in the left cochlea. The findings suggest that meningitis developed secondary to erosion of the temporal bone and ganglioneuritis and/or perineuritis of the vestibulocochlear nerve. Conclusions Middle ear tympanokeratoma is an important and potentially life-threatening otic condition in the dog. Once a tympanokeratoma has developed expansion of the cyst can lead to erosion of bone and extension of otic infection to the inner ear, vestibulocochlear ganglion and nerve potentially leading to bacterial infection of the central nervous system

Supplemental Material, DS1_VET_10.1177_0300985818777786 - Septic Arthritis/Osteomyelitis May Lead to Osteochondrosis-Like Lesions in Foals

<p>Supplemental Material, DS1_VET_10.1177_0300985818777786 for Septic Arthritis/Osteomyelitis May Lead to Osteochondrosis-Like Lesions in Foals by Bjørn Wormstrand, Liv Østevik, Stina Ekman, and Kristin Olstad in Veterinary Pathology</p