15 research outputs found

    Gangrenous dermatitis in chickens and turkeys

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    Gangrenous dermatitis (GD) is a disease of chickens and turkeys that causes severe economic losses in the poultry industry worldwide. Clostridium septicum, Clostridium perfringens type A, and occasionally Clostridium sordellii are considered the main causes of GD, although Staphylococcus aureus and other aerobic bacteria may also be involved in some cases of the disease. GD has become one of the most significant diseases of commercial turkeys in the United States. Several infectious and/or environmental immunosuppressive factors can predispose to GD. Skin lesions are considered to be the main portal of entry of the microorganism(s) involved. GD is characterized by acute onset of mortality associated with gross skin and subcutaneous tissue lesions consisting of variable amounts of serosanguineous exudate together with emphysema and hemorrhages. The underlying skeletal muscle can also be involved. Ulceration of the epidermis may be also noticed in cases complicated with S. aureus. Microscopically, necrosis of the epidermis and dermis, and subcutaneous edema and emphysema are commonly observed. Gram-positive rods can be identified within the subcutis and skeletal muscles, usually associated with minimal inflammatory infiltrate. A presumptive diagnosis of GD can be made based on history, clinical signs, and gross anatomic and microscopic lesions. However, confirmation should be based on demonstration of the causative agents by culture, PCR, immunohistochemistry, and/or fluorescent antibody tests.Facultad de Ciencias Veterinaria

    The feather epithelium contributes to the dissemination and ecology of clade 2.3.4.4b H5 high pathogenicity avian influenza viruses in ducks

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    Immature feathers are known replication sites for high pathogenicity avian influenza viruses (HPAIVs) in poultry. However, it is unclear whether feathers play an active role in viral transmission. This study aims to investigate the contribution of the feather epithelium to the dissemination of clade 2.3.4.4b goose/Guangdong/1996 lineage H5 HPAIVs in the environment, based on natural and experimental infections of domestic mule and Muscovy ducks. During the 2016-2022 outbreaks, H5 HPAIVs exhibited persistent and marked feather epitheliotropism in naturally infected commercial ducks. Infection of the feather epithelium resulted in epithelial necrosis and disruption, as well as the production and environmental shedding of infectious virions. Viral and feather antigens colocalized in dust samples obtained from poultry barns housing naturally infected birds. In summary, the feather epithelium contributes to viral replication, and it is a likely source of environmental infectious material. This underestimated excretion route could greatly impact the ecology of HPAIVs, facilitating airborne and preening-related infections within a flock, and promoting prolonged viral infectivity and long-distance viral transmission between poultry farms

    Utilisation d'une approche multidisciplinaire pour déterminer l'étiologie de syndromes cliniques chez une espèce aviaire menacée : l'exemple de l'Outarde Houbara

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    In the present work, we assessed the use of a multidisciplinary diagnostic approach to successfully investigate poorly characterized pathological entities using an endangered avian species as a model: the Houbara Bustard. This species is the object of several captive breeding operations located in North Africa, the United Arab Emirates and Central Asia. We focused our attention on three conditions that could potentially jeopardize conservation efforts: high pathogenicity avian influenza (HPAI), genital infections in artificially-inseminated breeders and a respiratory syndrome affecting outdoor birds destined to be released. For the first condition, we successfully validated an RNA scope in situ hybridization (ISH) assay for the detection of the avian influenza A virus matrix gene in formalin-fixed and paraffin-embedded (FFPE) tissues. We then provided the first comprehensive description of HPAI H5N8 natural infection in the Houbara, resulting in hyperacute and acute forms exhibiting marked tissue pantropism, endotheliotropism and neurotropism. For the second condition we characterized a series of cases of peritonitis and salpingo-peritonitis. Chronic forms predominated and an ascending infection was highly suspected. Most of the cases were associated with the isolation of Escherichia coli. The identification of a variety of virulence profiles by molecular analysis of selected bacterial isolates suggested the involvement of multiple strains. Furthermore, histopathology allowed the identification of changes consistent with cystic oviductal hyperplasia, expanding the list of potential risk factors involved in the development of genital infections in the Houbara Bustard.For the third condition, we were able to shed some light on a multifactorial respiratory syndrome, focusing on long-lasting, chronic forms. A variety of viral and bacterial pathogens were detected, including potentially a novel Mycoplasma species. Environmental conditions, such as heat stress and exposure to dust storms, were considered significant contributing factors. We showed that combining classical and novel diagnostic tools we were able to significantly improve the etiological diagnosis of emerging and re-merging conditions in the Houbara. This approach should be promoted to study sanitary issues in other endangered species, characterized by a limited availability of samples.Dans le travail présenté ici, nous avons évalué l’intérêt une approche diagnostique multidisciplinaire pour l’investigation d’entités pathologiques mal caractérisées en utilisant l’Outarde Houbara comme espèce modèle. Cette espèce fait l’objet de plusieurs projets d’élevages conservatoires en Afrique du Nord, au Moyen Orient et en Asie centrale. Nous nous sommes intéressés à trois entités pathologiques ayant toutes le potentiel de mettre en péril les efforts de conservation : l’influenza aviaire hautement pathogène (IAHP), les infections génitales chez les oiseaux inséminés artificiellement et un syndrome respiratoire affectant les oiseaux élevés à l’extérieur et devant à terme renforcer les populations sauvages. Pour la première entité, nous avons validé l’utilisation de l’hybridation in situ par RNAscope pour détecter le gène de matrice des virus influenza aviaires dans des tissus fixés au formol et inclus en paraffine. Cela nous a permis de décrire de manière exhaustive et pour la première fois un épisode infectieux à virus IAHP H5N8 chez l’Outarde Houbara, qui s’est manifestée par des formes cliniques suraigues à aigues de la maladie, associées à un pantropisme tissulaire, avec endothéliotropisme et neurotropisme viral. Pour la seconde entité pathologique, nous avons caractérisé une série de cas de péritonite et salpingo-péritonie associés à des infections par Escherichia coli. La diversité des profils de virulence de la bactérie, identifiée par biologie moléculaire, suggère l’implication de nombreuses souches. Les formes chroniques étaient prédominantes et une infection ascendante a été suspectée. De plus, l’examen histologique a permis l’identification de modifications tissulaires compatibles avec une hyperplasie cystique endométriale, pouvant intervenir comme facteur de risque dans le développement des infections génitales chez l’Houbara. Enfin, pour la troisième entité pathologique, nous nous sommes concentrés sur un syndrome respiratoire multifactoriel d’évolution essentiellement chronique. Divers agents pathogènes ont été détectés chez les oiseaux affectés, y compris une espèce potentiellement nouvelle de Mycoplasme. Des facteurs environnementaux, comme le stress thermique et l’exposition à des tempêtes de sable sont considérés comme des facteurs contributifs importants. Nous avons montré dans ce travail que nous améliorions considérablement le diagnostic étiologique des affections émergentes et réémergentes chez l’Outarde Houbara par une approche multidisciplinaire. Cette approche devrait être encouragée pour étudier la santé d’autres espèces menacées, notamment lors d’une disponibilité limitée en échantillons

    Gangrenous dermatitis in chickens and turkeys

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    Gangrenous dermatitis (GD) is a disease of chickens and turkeys that causes severe economic losses in the poultry industry worldwide. Clostridium septicum, Clostridium perfringens type A, and occasionally Clostridium sordellii are considered the main causes of GD, although Staphylococcus aureus and other aerobic bacteria may also be involved in some cases of the disease. GD has become one of the most significant diseases of commercial turkeys in the United States. Several infectious and/or environmental immunosuppressive factors can predispose to GD. Skin lesions are considered to be the main portal of entry of the microorganism(s) involved. GD is characterized by acute onset of mortality associated with gross skin and subcutaneous tissue lesions consisting of variable amounts of serosanguineous exudate together with emphysema and hemorrhages. The underlying skeletal muscle can also be involved. Ulceration of the epidermis may be also noticed in cases complicated with S. aureus. Microscopically, necrosis of the epidermis and dermis, and subcutaneous edema and emphysema are commonly observed. Gram-positive rods can be identified within the subcutis and skeletal muscles, usually associated with minimal inflammatory infiltrate. A presumptive diagnosis of GD can be made based on history, clinical signs, and gross anatomic and microscopic lesions. However, confirmation should be based on demonstration of the causative agents by culture, PCR, immunohistochemistry, and/or fluorescent antibody tests.Facultad de Ciencias Veterinaria

    Captive Psittacines with Chlamydia avium Infection

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    Avian chlamydiosis is an infection caused by obligate intracellular, gram-negative bacteria belonging to the Chlamydiaceae family. Birds can be hosts of several Chlamydia species, including Chlamydia avium, which has only been detected in pigeons and psittacine birds. In this study, depression, respiratory distress, and mortality were noted among psittacines belonging to a large aviary with 35 different avian species. On the basis of immunohistochemistry and PCR testing, chlamydiosis was diagnosed in affected birds. Gross and histopathologic lesions were mainly observed in the spleen and gastrointestinal tract. Chlamydia avium was detected in four psittacines by PCR, including two dead birds and two individuals exhibiting respiratory distress. Increased aspartate aminotransferase and lactate dehydrogenase values and anemia were consistently identified in affected birds. Administration of doxycycline, combined with hepatoprotectors and vitamins, was effective in stopping mortality and bacterial shedding
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