Protection of Broiler Chickens Against Necrotic Enteritis by Intrapulmonary Delivery of a Live Clostridium perfringens Vaccine Exploiting the Gut-Lung-Axis Concept.

Clostridium perfringens (CP)-induced necrotic enteritis (NE) is an economically important disease in the broiler chicken industry. The incidence of NE is common in 3-to-6-wk-old broiler chickens, once maternal antibodies start declining. Developing an effective vaccination strategy against NE, preferably delivering a single dose of vaccine at hatch to protect broiler chickens against NE without a booster vaccine, is an enormous challenge. The objective of this study was to induce mucosal immunity in the intestines against NE by intrapulmonary (IPL) delivery of a live CP vaccine at hatch, exploiting the gut-lung-axis (GLA) concept by vaccine delivery following in ovo administration of cytosine-phosphorothioate-guanine oligodeoxynucleotides (CpG-ODN) to induce immune cell maturation in the lungs. Experiments were conducted to explore the dose of CP and immune protection against heterologous CP challenge, and to study the efficacy of IPL delivery of a CP vaccine without a booster. Additional studies were conducted to measure serum immunoglobulin (Ig)Y, mucosal IgA, and histopathology of lungs following vaccination. Delivery of a live CP vaccine by the IPL route, with or without in ovo CpG-ODN, provided significant protection against NE (P < 0.0001). Systemic IgY and mucosal IgA against CP were correlated with protection against NE. There was no necrosis or inflammation in the pulmonary parenchyma. There was a low number of CP isolated from the lungs following live CP delivery by the IPL route. A significant influx of (P < 0.001) of CD8+ T cells and macrophages were noted in the lungs 2 days following live CP delivery by the IPL route. IPL delivery of a live CP vaccine, rather than inactivated CP, provided better protection. This study demonstrated the utility in exploiting the GLA concept in vaccine delivery in broiler chickens.

Protección de pollos de engorde contra la enteritis necrótica mediante la administración intrapulmonar de una vacuna viva de Clostridium perfringens que aprovecha el concepto del eje intestino-pulmón. La enteritis necrótica (NE) inducida por Clostridium perfringens (CP) es una enfermedad económicamente importante en la industria de los pollos de engorde. La incidencia de enteritis necrótica es común en pollos de engorde de tres a seis semanas de edad, una vez que los anticuerpos maternos comienzan a disminuir. El desarrollo de una estrategia de vacunación eficaz contra la enteritis necrótica, preferiblemente administrando una dosis única de vacuna en la eclosión para proteger a los pollos de engorde contra dicha enfermedad sin la necesidad de aplicar una vacuna de refuerzo, es un desafío importante. El objetivo de este estudio fue inducir inmunidad de mucosas en los intestinos contra la enteritis necrótica mediante la administración intrapulmonar (IPL) de una vacuna de C. perfringens viva en la eclosión, explotando el concepto del eje intestino-pulmón (GLA) mediante la administración de la vacuna después de la administración in ovo de citosin oligodesoxinucleótidos de fosforotioato-guanina (CpG-ODN) para inducir la maduración de las células inmunitarias en los pulmones. Se realizaron experimentos para explorar la dosis de C. perfringens y la protección inmune contra la exposición heteróloga a C. perfringens, y para estudiar la eficacia de la administración intrapulmonar de una vacuna C. perfringens sin refuerzo. Se realizaron estudios adicionales para medir la inmunoglobulina (Ig)Y sérica, la IgA de mucosas y la histopatología de los pulmones después de la vacunación. La administración de una vacuna de C. perfringens viva por vía intrapulmonar, con o sin CpG-ODN in ovo, proporcionó una protección significativa contra la enteritis necrótica (P < 0.0001). La IgY sistémica y la IgA mucosa contra C. perfringens se correlacionaron con la protección contra la enteritis necrótica. No hubo necrosis ni inflamación en el parénquima pulmonar. Hubo un número bajo de C. perfringens aislado de los pulmones después de la administración de la vacuna viva contra C. perfringens por vía intrapulmonar. Se observó una afluencia significativa (P < 0.001) de células T CD8+ y macrófagos en los pulmones dos días después de la administración de C. perfringens viva por vía intrapulmonar. La administración mediante vía intrapulmonar de una vacuna viva contra C. perfringens, en lugar de la vacuna contra C. perfringens inactivada, proporcionó una mejor protección. Este estudio demostró la utilidad de explotar el concepto del eje intestino-pulmón en la administración de vacunas en pollos de engorde.

An outbreak of ischaemic teat necrosis in a dairy herd in Taranaki, New Zealand.

CASE HISTORY: In spring 2021, on a seasonally calving, pastorally based, Taranaki dairy farm, 12 first-calving heifers (≤ 30 days post-calving) developed similar dry, red to black, crusting lesions on the medial aspect of the teat udder junction extending down the medial teat. Some cows had multiple teats affected. Treatment was initially unrewarding and did not slow the progression of the disease. Overall, 8/12 cows recovered, and 4/12 cows were culled, with three of the cows culled after a teat sloughed and the fourth after surgical amputation of a teat. Outbreaks of the same condition, on the same farm but affecting fewer animals, occurred in spring 2022 (n = 6) and spring 2023 (n = 3). CLINICAL FINDINGS: An initial scab-like or crusting lesion progressed to resemble a thick eschar consisting of very dry and hard dead tissue. The unaffected areas of the teat felt normal but immediately under the dead tissue, there was a warm, firmer area consistent with an inflammatory reaction. Removing the scab led to profuse bleeding, with no visible bed of granulation underneath the scab. There was no leaking of milk in those cows that lost a teat, and no smell to the lesions themselves. Serology and virology ruled out the involvement of bovine alphaherpesvirus (BoHV-2) bovine gammaherpesvirus (BoHV-4), orthopoxviruses (cowpox) and parapoxviruses (pseudocowpox). Histopathology of an affected and surgically amputated teat showed multifocal erosion and ulceration of the epidermis, covered by a thick serocellular crust. In areas of ulceration, there were numerous neutrophils, and the dermis was expanded by granulation tissue with variable numbers of neutrophils, eosinophils, and lymphocytes around small blood vessels. DIAGNOSIS: Based on the similarity of the history, presentation, and histopathological changes to those described for a novel disease reported in the UK, a diagnosis of ischaemic teat necrosis (ITN) was made. CLINICAL RELEVANCE: If ITN is an emerging condition in New Zealand and becomes as prevalent as it has in the UK, clinicians will be confronted with a significant new welfare problem in dairy cows. Anecdotally, there have been reports of other ITN outbreaks in New Zealand, and the Ministry for Primary Industries would be interested in collating reports from other New Zealand veterinarians.

Acanthocephaliasis by Plagiorhynchus sp. (Acanthocephala:Plagiorhynchidae) associated with necrotic enteritis in quetzals (Pharomachrus mocinno) maintained in captivity.

The present report describes a case of acanthocephaliasis associated with necrotic enteritis in quetzals (Pharomachrus mocinno). Three juvenile quetzals exhibited depression, anorexia, ruffled feathers, and sudden death. They were submitted to the laboratory for examination. The birds had hatched and lived in captivity in an aviary in Mexico. Gross lesions observed were hemorrhagic, fibrinoid necrotic enteritis, with acanthocephalans adhered to the intestinal mucosa. The specimens were identified by parasitology, electronic microscopy, and molecular biology as Plagiorhynchus (Prosthorhynchus) sp. Lesions compatible with necrotic enteritis were also confirmed by isolation and genotyping of Clostridium perfringens type E. This is the first report of Plagiorhynchus (Prosthorhynchus) sp. in quetzals in captivity in Mexico. The findings in this manuscript suggest that this parasite could be a predisposing factor for necrotic enteritis as well as a risk component in the breeding programs and survival of this avian species in captivity.

Clostridium perfringens antigens and challenges for development of vaccines against necrotic enteritis in poultry.

INTRODUCTION: Chickens with Necrotic Enteritis (NE), caused by Clostridium perfringens, exhibit acute and chronic symptoms that are difficult to diagnose, leading to significant economic losses. Vaccination is the best method for controlling and preventing NE. However, only two vaccines based on the CPA and NetB toxins have been commercialized, offering partial protection, highlighting the urgent need for more effective vaccines. OBJECTIVE: This review aimed to identify promising antigens for NE vaccine formulation and discuss factors affecting their effectiveness. METHODS: A systematic review using five scientific databases identified 30 eligible studies through the Rayyan tool, which were included for quality review. RESULTS: We identified 25 promising antigens, including CPA, NetB, FBA, ZMP, CnaA, FimA, and FimB, categorized by their role in disease pathogenesis. This review discusses the biochemical, physiological, and genetic traits of recombinant antigens used in vaccine prototypes, their expression systems, and immunization potential in chickens challenged with virulent C. perfringens strains. Market supply challenges, immunogenic potential, vaccine platforms, adjuvants, and factors related to vaccination schedules-such as administration routes, dosing intervals, and age at immunization-are also addressed. Additionally, the study notes that vaccine formulations tested under mild challenges may not offer adequate field-level protection due to issues replicating aggressive conditions, strain virulence loss, and varied methodologies. CONCLUSIONS: An ideal NE vaccine should incorporate multiple antigens, molecular adjuvants, and delivery systems via in ovo and oral routes. The review underscores the challenges in developing and validating NE vaccines and the urgent need for a standardized protocol to replicate aggressive challenges accurately.

Shar-Pei autoinflammatory disease with skin necrosis due to neutrophilic vasculitis: a case report.

A 4-month-old female Shar-pei dog was admitted with apathy, anorexia, and vomiting. The patient had an appropriate vaccination protocol, with the last vaccine administered 2.5 weeks prior to the onset of clinical signs. Physical examination revealed tachycardia, fever and swelling of the tibiotarsal joints. Several diagnostic tests including complete blood cell count, biochemistry profile, urinalysis, thoracic radiographs, hind limbs radiographs, abdominal ultrasound, and infectious diseases tests, were conducted to determine the underlying cause. Shar-Pei Auto-inflammatory Disease (SPAID) was diagnosed. Additionally, the patient developed skin necrosis in the inner aspect of the tibiotarsal joints as a complication. A skin biopsy revealed cutaneous vasculopathy causing degeneration, abrupt ulceration, and ischemic necrosis with intense neutrophilic inflammation of the dermis and subcutis. Moreover, a hospital-acquired infection was identified by skin culture. Debridement of the necrotic skin was performed, and due to its' severity and extent, the wound was closed by secondary intention. A diagnostic protocol and the therapeutic dose of acetylsalicylic acid, which led to clinical improvement, are recommended here. The patient has continued to present episodic manifestations of SPAID mainly fever and swelling of the tibiotarsal joints, but there has been no recurrence of necrosis or other cutaneous lesion in the last two years.

Alternative to antimicrobial growth promoters in the diets of broilers challenged with subclinical necrotic enteritis.

Necrotic enteritis (NE) is a disease of worldwide distribution, which affects young broilers and causes economic losses on a scale of 6 billion dollars per year. For decades, NE was controlled in poultry flocks by dietary administration of low doses of antimicrobial growth promoters (AGPs). However, an increase in NE incidence was noted after the AGP ban. This study aimed to compare the effect of an antibiotic (Enramycin) diet to a combination of sodium butyrate, hydrolyzed yeast, and zinc proteinate (ViligenTM) on broiler diets regarding performance, blood parameters, intestinal permeability, morphology and lesions, and carcass yield of broilers challenged with Eimeria spp. and Clostridium perfringens to simulate subclinical necrotic enteritis. A total of 1,150 one-day-old male broiler chickens with an initial average weight of 43.9 ± 0.65 g were allocated to 50 experimental pens. Animals were divided into 5 groups: Negative control (NC) without additives; Positive control (PC) with 0.12 g/ton of Enramycin (8%); V500, V1000, and V1500 with the addition of 500, 1.000, and 1.500 g/ton of Viligen, respectively. All animals were challenged by Eimeria spp. at 7 d of age and by C. perfringens at 17, 18, and 19 d for induction of subclinical NE. The broilers fed with all concentrations of Viligen showed similar performance, blood parameters, intestinal permeability, and carcass yield compared to PC broilers. However, NC broilers showed higher FCR compared to PC broilers from 1 to 33 d (1.42 vs. 1.39) (P = 0.048) and from 1 to 42 d (1.51 vs. 1.49) (P < 0.001). V1500 broilers had fewer intestinal lesions at 28 d when compared to the PC treatment (P < 0.05) and showed that higher Viligen inclusion resulted in lower intestinal damage. At 21 d, the V500 group showed higher intestinal morphology characteristics (VH:VD 4.9 vs. 3.5) compared to the PC treatment (P < 0.001). Thus, in this study, the dietary addition of Viligen to broilers challenged by an experimental model of subclinical NE resulted in lower intestinal damage and similar performance to that obtained by the addition of Enramycin.

Efficacy of Bacillus subtilis probiotic in preventing necrotic enteritis in broilers: a systematic review and meta-analysis.

Probiotics can enhance broiler chicken health by improving intestinal microbiota, potentially replacing antibiotics. They protect against bacterial diseases like necrotic enteritis (NE) in poultry. Understanding their role is crucial for managing bacterial diseases, including NE. This study conducted a meta-analysis to assess the effects of Bacillus subtilis probiotic supplementation on feed conversion ratio (FCR), NE lesion score, and mortality. Additionally, a systematic review analysed gut microbiota changes in broilers challenged with Clostridium perfringens with or without the probiotic supplementation. Effect sizes from the studies were estimated in terms of standardized mean difference (SMD). Random effect models were fitted to estimate the pooled effect size and 95% confidence interval (CI) of the pooled effect size between the control [probiotic-free + C. perfringens] and the treatment [Bacillus subtilis supplemented + C. perfringens] groups. Overall variance was computed by heterogeneity (Q). The meta-analysis showed that Bacillus subtilis probiotic supplementation significantly improved FCR and reduced NE lesion score but had no effect on mortality rates. The estimated overall effects of probiotic supplementation on FCR, NE lesion score and mortality percentage in terms of SMD were -0.91 (CI = -1.34, -0.49; P < 0.001*); -0.67 (CI = -1.11, -0.22; P = 0.006*), and -0.32 (CI = -0.70, 0.06; P = 0.08), respectively. Heterogeneity analysis indicated significant variations across studies for FCR (Q = 69.66; P < 0.001*) and NE lesion score (Q = 42.35; P < 0.001*) while heterogeneity was not significant for mortality (Q = 2.72; P = 0.74). Bacillus subtilis probiotic supplementation enriched specific gut microbiota including Streptococcus, Butyricicoccus, Faecalibacterium, and Ruminococcus. These microbiotas were found to upregulate expression of various genes such as TJ proteins occluding, ZO-1, junctional adhesion 2 (JAM2), interferon gamma, IL12-ß and transforming growth factor-ß4. Moreover, downregulated mucin-2 expression was involved in restoring the intestinal physical barrier, reducing intestinal inflammation, and recovering the physiological functions of damaged intestines. These findings highlight the potential benefits of probiotic supplementation in poultry management, particularly in combating bacterial diseases and promoting intestinal health.

Resolution of necrotizing cellulitis in a dog using basic wound management.

An 8-month-old intact male golden retriever dog was seen as a case requiring urgent attention 2 d after an altercation with a cat. The dog was febrile, anorexic, and reluctant to move. There was soft-tissue swelling on the left ventral abdomen that progressed to necrotizing cellulitis. Despite the severity of the wound, client financial constraints necessitated management on a low-cost, outpatient basis using empirical antibiotics and raw-honey bandages. The wound resolved fully in 5 wk.

Résolution de cellulite nécrosante chez un chien grâce à la gestion de base des plaies. Un chien golden retriever mâle intact de 8 mois a été considéré comme un cas nécessitant une attention urgente 2 jours après une altercation avec un chat. Le chien était fébrile, anorexique et hésitait à bouger. Il y avait une enflure des tissus mous sur l'abdomen ventral gauche qui a évolué vers une cellulite nécrosante. Malgré la gravité de la blessure, les contraintes financières des clients ont nécessité une prise en charge ambulatoire à faible coût, utilisant des antibiotiques empiriques et des bandages au miel cru. La plaie s'est complètement résolue en 5 semaines.(Traduit par Dr Serge Messier).

Necrosis plays a role in the concentration of mycobacterial antigens in granulomas from Mycobacterium bovis naturally infected cattle.

The dynamics that develop between cells and molecules in the host against infection by Mycobacterium bovis, leads to the formation of granulomas mainly present in the lungs and regional lymph nodes in cattle. Cell death is one of the main features in granuloma organization, however, it has not been characterized in granulomatous lesions caused by M. bovis. In this study we aimed to identify the profiles of cell death in the granuloma stages and its relationship with the accumulation of bacteria. We identified necrosis, activated caspase-3, LC3B/p62 using immunohistochemistry and digital pathology analysis on 484 granulomatous lesions in mediastinal lymph nodes from 23 naturally infected cattle. Conclusions: greater amounts of mycobacterial antigens were identified in granulomas from calves compared with adult cattle. The highest percentage of necrosis and quantity of mycobacterial antigens were identified in granuloma stages (III/IV) from adults. The LC3B/p62 profile was heterogeneous in granulomas between adults and calves. Our data suggest that necrosis is associated with a higher amount of mycobacterial antigens in the late stages of granuloma and the development of autophagy appears to play an heterogeneous effector response against infection in adults and calves. These results represent one of the first approaches in the identification of cell death in the four stages of granulomas in bovine tuberculosis.

Mannheimia haemolytica-associated fibrinonecrotizing abomasitis in lambs.

Mannheimia haemolytica-associated abomasitis has been clinically described as a cause of sudden death in lambs, but it is poorly characterized. We describe the pathological features of a severe fibrinonecrotizing abomasitis in 3 lambs that died suddenly. All 3 abomasums had a thickened submucosa due to edema and necrotic areas delimited by bands of degenerate neutrophils with slender nuclei (oat cells) and angiocentric distributions. The overlying mucosa was congested. Myriads of gram-negative coccobacilli were observed within the oat cell bands. M. haemolytica was isolated from the abomasum in all 3 animals and was serotyped as A2 in one of them. Pericarditis and pleuritis were observed in 2 of the lambs. Clostridium spp. were isolated in 1 lamb and detected by immunohistochemistry in the 3 animals, suggesting clostridial co-infection. M. haemolytica should be considered among the differential diagnoses of necrotizing abomasitis in lambs.

In vitro and in vivo evaluation of the efficacies of commercial probiotics and disinfectant against acute hepatopancreatic necrosis disease and luminescent vibriosis in Litopenaeus vannamei.

The bioactivities of two commercially available probiotics and one chemical disinfectant were tested against strains of Vibrio parahaemolyticus (VPAHPND) and V. harveyi. This study aimed to determine shrimp pathogenic Vibrios' in vitro and in vivo sensitivities to commercial probiotics and a chemical disinfectant. The probiotics and disinfectant were tested first in vitro, followed by the in vivo trials. Results showed that upon administration of probiotics either through diet or adding into the tank water, the survivability of shrimp was increased during challenge with VPAHPND and V. harveyi. Also, the disinfectant was tested against the same pathogens and showed positive bactericidal effects at 2500 ppm and 5000 ppm. The present findings suggest that adding probiotics to the rearing water or the shrimp feeds effectively prevents infection by lowering the load of pathogenic bacteria. In comparison, the effectiveness of the disinfectant (PUR) depends on its appropriate concentration and timing of application. It is not only limited to rearing water but is also applicable for decontaminating pond liners, tanks, and other paraphernalia.

Comparison of necrotic enteritis effects on growth performance and intestinal health in two different meat-type chicken strains Athens Canadian Random Bred and Cobb 500.

Chickens have undergone genetic improvements in the past few decades to maximize growth efficiency. However, necrotic enteritis (NE), an enteric disease primarily caused by C. perfringens, remains a significant problem in poultry production. A study investigated the differences in intestinal health between the nonselected meat-type chicken Athens Canadian Random Bred (ACRB) and the modern meat-type Cobb 500 broilers (Cobb) when challenged with experimental NE. The study utilized a 2 × 3 factorial arrangement, consisting of two main effects of chicken strain and NE challenge model (nonchallenged control, NC; NE challenge with 2,500/12,500 Eimeria maxima oocysts + 1 × 109C. perfringens, NE2.5/NE12.5). A total of 432 fourteen-day-old male ACRB and Cobb were used until 22 d (8 d postinoculation with E. maxima on d 14, dpi), and the chickens were euthanized on 6 and 8 dpi for the analysis. All data were statistically analyzed using a two-way ANOVA, and Student's t-test or Tukey's HSD test was applied when P < 0.05. The NE12.5 group showed significant decreases in growth performance and relative growth performance from d 14 to 20, regardless of chicken strain (P < 0.01). The ACRB group exhibited significant decreases in relative body weight and relative body weight gain compared to the Cobb group from d 14 to 22 (P < 0.01). On 6 and 8 dpi, both NE challenge groups showed significant decreases in intestinal villus height to crypt depth ratio, jejunal goblet cell count, and jejunal MUC2 and LEAP2 expression (P < 0.01). Additionally, the NE12.5 group had significantly higher intestinal NE lesion score, intestinal permeability, fecal E. maxima oocyst count, intestinal C. perfringens count, and jejunal IFNγ and CCL4 expression compared to the NC group (P < 0.05). In conclusion, NE negatively impacts growth performance and intestinal health in broilers, parameters regardless of the strain.

Bacillus subtilis HW2 enhances growth performance and alleviates gut injury via attenuation of endoplasmic reticulum stress and regulation of gut microbiota in broilers under necrotic enteritis challenge.

This study investigated the effects of Bacillus subtilis HW2 on the growth performance, immune response, endoplasmic reticulum (ER) stress, and intestinal health in broilers with necrotic enteritis. Three hundred 1-day-old male Cobb 500 broilers (33.88 ± 2.34 g) were randomly allocated to 5 groups including non-infected control (NC group), basal diet + necrotic enteritis challenge (NE group), basal diet + 1 × 106 CFU/g B. subtilis HW2 + necrotic enteritis challenge (L-Pro group), basal diet + 5 × 106 CFU/g B. subtilis HW2 + necrotic enteritis challenge (M-Pro group), and basal diet + 1 × 107 CFU/g B. subtilis HW2 + necrotic enteritis challenge (H-Pro group), with 6 replicates per group. All broilers except NC group were orally given with sporulated coccidian oocysts at day 14 and Clostridium perfringens from days 19 to 21. Results showed that L-Pro and M-Pro groups improved growth performance and intestinal morphology in necrotic enteritis-challenged broilers, and L-Pro, M-Pro, and H-Pro groups improved intestinal barrier function and immune response and decreased ER stress in necrotic enteritis-challenged broilers. Analysis of the gut microbiota revealed that L-Pro group increased the abundances of Alistipes, Coprobacter, Barnesiella, and Limosilactobacillus, decreased Erysipelatoclostridium abundance on day 42 in necrotic enteritis-challenged broilers. M-Pro group increased Turicibacter abundance on day 28 and the abundances of Alistipes, Barnesiella, and Limosilactobacillus on day 42 in necrotic enteritis-challenged broilers. H-Pro group decreased Romboutsia abundance on day 28 and unidentified_Clostridia abundance on day 42 in necrotic enteritis-challenged broilers. Analysis of short-chain fatty acids (SCFAs) revealed higher isobutyric acid and isovaleric acid levels in L-Pro and M-Pro groups than NE group. Correlation analysis revealed the correlations between the biochemical parameters and gut microbiota as well as SCFAs, especially Romboutsia, Barnesiella, Coprobacter, isobutyric acid, and isovaleric acid. Overall, our results indicated that B. subtilis HW2 supplementation could ameliorate necrotic enteritis infection-induced gut injury. The optimal dietary supplementation dosage of Bacillus subtilis HW2 was 5 × 106 CFU/g.

West Nile Virus Infection in a Pekin Duck ( Anas platyrhynchos domesticus ) Developer Flock.

Developer ducks are ducks being reared for breeding. Like breeder candidate chickens, they are raised with appropriate light and feed programs. A commercial Pekin duck (Anas platyrhynchos domesticus) developer flock experienced an extraordinary, elevated mortality event at 6 wk of age. Weekly mortality rate that week was 162 ducklings out of a flock of 6420 (2.5%). Mortality jumped to 988 (15.4%) ducklings the next week. On first elevated mortality, six dead ducks from that flock were submitted for diagnostic investigation at Michigan State University Veterinary Diagnostic Laboratory. Myocarditis, pale striping or diffuse pallor of the epicardium, was grossly evident in five of the six submitted ducklings. All of the ducklings had hydropericardium, three had ascites, and three had congested meninges. Histology confirmed myocarditis with myocardial necrosis. Cerebrum and brainstem had lymphocytic vasculitis with rare neuronal necrosis in affected areas, as well as Purkinje cells in the cerebellum. West Nile virus was confirmed by PCR the day after submittal and by immunohistochemistry soon thereafter.

Reporte de caso- Infección por el virus del Nilo occidental en una parvada en desarrollo de patos Pekin (Anas platyrhynchos domesticus) reproductores. Los patos reproductores en desarrollo son patos que se crían para la reproducción. Al igual que los pollos candidatos para reproducción, se crían con programas de iluminación y alimentación adecuados. Una parvada comercial en desarrollo de pato Pekín (Anas platyrhynchos domesticus) experimentó un evento de mortalidad elevada y extraordinaria a las seis semanas de edad. La tasa de mortalidad semanal de esa semana fue de 162 patitos de una parvada de 6420 (2.5%). La mortalidad se elevó a 988 (15.4%) patitos la semana siguiente. En el primer aumento de mortalidad, seis patos muertos de esa bandada fueron enviados para una investigación de diagnóstico en el Laboratorio de Diagnóstico Veterinario de la Universidad Estatal de Michigan. La miocarditis, caracterizada por rayas pálidas o palidez difusa del epicardio, fue evidente en cinco de los seis patitos presentados. Todos los patitos mostraron hidropericardio, tres tenían ascitis y tres tenían meninges congestionadas. La histología confirmó miocarditis con necrosis miocárdica. El cerebro y el tronco del encéfalo tenían vasculitis linfocítica con rara necrosis neuronal en las áreas afectadas, así como de las células de Purkinje en el cerebelo. El virus del Nilo Occidental se confirmó mediante PCR el día después de la llegada al laboratorio y mediante inmunohistoquímica poco tiempo después.

Inducing experimental bacterial chondronecrosis with osteomyelitis lameness in broiler chickens using aerosol transmission model.

Lameness disease attributed to bacterial chondronecrosis with osteomyelitis in broilers affects production, animal welfare, and food safety in the poultry industry. The disease is characterized by necrotic degeneration of the rapidly growing femora and tibiae due to bacterial translocation from the respiratory or gastrointestinal tracts into the blood circulation, eventually colonizing the growth plate of the long bones. To investigate the etiology, pathogenesis, and intervention measures for BCO, developing an experimental model that reliably induces BCO lameness is of the utmost importance. In the past, we have employed a wire-flooring model and a litter-flooring model administered with a bacterial challenge to investigate strategies for mitigating BCO. However, multiple issues on labor-intensive barn setup and cleanout efforts for the wire-flooring system and concern of direct pathogenic exposure to the broilers for the litter-flooring models rendered these research models less effective. Thus, we investigated a new approach to induce experimental BCO lameness using an aerosol transmission model employing a group of birds reared on wire-flooring pens as a BCO infection source, and the disease is further disseminated through the airborne transmission to other birds reared on litter flooring in the same housing environment. The effectiveness of the aerosol transmission model in inducing BCO lameness was concluded from 4 independent experiments. The cumulative lameness generated from the BCO source group on the wire floors versus negative control treatments on the litter floors from Experiments 1, 2, 3, and 4 were 84% vs. 69.33%, P = 0.09; 54.55% vs. 60%, P = 0.56; 78% vs. 73.50%, P = 0.64; 81% vs. 74.50%, P = 0.11. Overall, the cumulative lameness generated from the wire floors was successfully transmitted to the birds on litter floors without significant statistical differences (P > 0.05). The effectiveness of the aerosol transmission model for experimentally triggering BCO lameness provides a reliable system for evaluating practical intervention strategies for BCO lameness in broilers.

Determination of the virulence status of Clostridium perfringens strains using a chicken intestinal ligated loop model is important for understanding the pathogenesis of necrotic.

Necrotic enteritis (NE) is a poultry intestinal disease caused by virulent strains of the bacterium Clostridium perfringens (C. perfringens). This anaerobic bacterium produces a wide range of enzymes and toxins in the gut which leads to NE development. It is generally accepted by the poultry veterinarians that netB-positive C. perfringens strains are virulent and netB-negative strains do not cause NE. However, NE pathogenesis remains unclear as contradictory results have been reported. The use of experimental in vivo models is a valuable tool to understand the pathogenesis of a disease. In this study, a chicken ligated loop model was used to determine the virulence status of 79 C. perfringens strains from various geographical locations, sources, and genotype profiles. According to our model and based on histologic lesion scoring, 9 C. perfringens strains were classified as commensal, 35 as virulent, and 34 as highly virulent. The virulence of only 1 C. perfringens strain could not be classified as its lesion score was variable (from <10 to >15). In general, NE lesions were more severe in intestinal loops inoculated with netB-positive C. perfringens strains than those inoculated with netB-negative strains. The prevalence of netB among strains classified as commensal, virulent, and highly virulent was 56% (5/9), 54%, (19/35), and 59% (20/34). These results suggest that NetB is not required to cause NE lesions and that other factors are also involved. The classification of the virulence status of C. perfringens strains should not be based solely on the presence or absence of this toxin. Therefore, the use of an in vivo model is essential to distinguish commensal from virulent strains of C. perfringens.

Outbreak of epizootic hemorrhagic disease in captive reindeer (Rangifer tarandus).

In September 2020, an outbreak of epizootic hemorrhagic disease occurred in captive reindeer (Rangifer tarandus) and was associated with neurological signs and mortality. Four reindeer died or were euthanized after acute illness over a 12-day period. Affected reindeer displayed abnormal behavior, neurologic signs, lethargy, and/or lameness. The most consistent gross finding was dark red streaks throughout the adrenal gland cortices (4/4). One animal had acute hemorrhage involving the subcutis and skeletal muscles over the ventrolateral body wall and back, and abomasal serosa. Histologically, the most common lesions were adrenal gland cortical hemorrhage (4/4) with necrosis (3/4) and lymphoplasmacytic meningoencephalitis with gliosis, glial nodules, satellitosis, and nonsuppurative perivascular cuffing (4/4). The brain lesions were most frequent in the gray matter of the cerebrum, hippocampus, and thalamus but also involved the cerebellum and brainstem. Epizootic hemorrhagic disease virus serotype 6 was detected through PCR and sequencing of the spleen in all cases.

Concurrent hepatopathy in dogs with gallbladder mucocele: Prevalence, predictors, and impact on long-term outcome.

BACKGROUND: Information is limited regarding the prevalence and importance of hepatic histologic abnormalities in dogs with gallbladder mucocele (GBM). OBJECTIVES: To (a) report prevalence of hepatic histologic abnormalities in dogs with GBM (b) evaluate for association between hepatic abnormalities and outcome in dogs with GBM (c) evaluate whether neutrophil-to-lymphocyte ratio (NLR) differs in dogs with GBM with and without specific hepatic lesions. ANIMALS: Fifty-two dogs with grossly and histologically confirmed GBM. METHODS: Multicenter, retrospective study of dogs with GBM undergoing cholecystectomy with concurrent liver biopsy. Archived histological sections of gallbladder and liver evaluated by investigators blinded to data. Proportions of dogs with each histologic abnormality alive vs deceased at 1, 3, and 12 months post-cholecystectomy compared. Mann-Whitney U performed to determine if NLR differed in dogs with or without selected lesions. RESULTS: 51/52 (98%, 95% CI [89%, 99%]) dogs with GBM had at least 1 hepatic histologic abnormality. Hepatic fibrosis (37/51; 73%, 95% CI [59%, 83%]), biliary hyperplasia (29/52; 56%, 95% CI [42%, 68%]), and portal inflammation (25/52; 48%, 95% CI [35%, 61%]) were most common. The proportion of dogs alive vs dead differed based on the fibrosis score at 1, 3, and 12 (P ≤ .04) months post-cholecystectomy. Dogs with hepatic necrosis (P = .006) and cholangitis/cholangiohepatitis (P = .02) had higher NLRs compared to dogs without these lesions. CONCLUSIONS AND CLINICAL IMPORTANCE: Histologic abnormalities of the liver are common in dogs with GBM. A higher portal fibrosis score might be associated with shortened long-term survival after cholecystectomy for dogs with GBM. An increase in NLR might predict hepatic necrosis and cholangitis/cholangiohepatitis in dogs with GBM.

Early decrease of ionized calcium and static symmetric dimethylarginine concentration in a model of renal tubular necrosis in corn snakes (Pantherophis guttatus).

OBJECTIVE: To determine if plasma concentrations of symmetric dimethylarginine (SDMA), N-acetyl-beta-d-glucosaminidase (NAG), GGT, ALT, AST, lactate, total calcium, and ionized calcium (iCa) and the calcium:phosphorus ratio are clinically relevant biomarkers to detect early stages of tubular lesions in snakes. ANIMALS: 6 adult corn snakes (Pantherophis guttatus). METHODS: Corn snakes were administered 11 injections of gentamicin at 50 mg/kg, SC, q 24 h in an experimental model of induced tubular necrosis. Plasma biochemistry and blood gas analyses were performed at baseline and after the 3rd and 11th injections. Parameters were compared between time points using a paired Wilcoxon test. In 3 individuals, renal biopsies were collected at baseline before starting injections and at the 3rd and 11th injections, while renal tissue samples were procured after euthanasia in all individuals. RESULTS: Renal proximal and distal tubular necrosis and hepatic steatosis were present in all individuals at necropsy. Compared to baseline, decreased blood concentrations of lactate, ionized calcium, and total calcium and a decreased calcium:phosphorus ratio were noted. A significant decrease of lactate and ionized calcium was observed after 3 days. Conversely, no changes in SDMA, NAG, ALT, AST, GGT, and sodium were detected. CLINICAL RELEVANCE: Ionized calcium and lactate concentrations were the earliest parameters to decrease compared to baseline values in this experimental model. While SDMA is a sensitive indicator of renal disease in mammals, this biomarker did not increase in a model of induced acute tubular necrosis in corn snakes.

Identification, pathological, and genomic characterization of novel goose reovirus associated with liver necrosis in geese, China.

Since 2021, a novel strain of goose reovirus (GRV) has emerged within the goose farming industry in Guangdong province, China. This particular viral variant is distinguished by the presence of white necrotic foci primarily localized in the liver and spleen, leading to substantial economic losses for the poultry industry. However, the etiology, prevalence and genomic characteristics of the causative agent have not been thoroughly investigated. In this study, we conducted an epidemiological inquiry employing suspected GRV samples collected from May 2021 to September 2022. The macroscopic pathological and histopathological lesions associated with GRV-infected clinical specimens were examined. Moreover, we successfully isolated the GRV strain and elucidated the complete genome sequence of the isolate GD21/88. Through phylogenetic and recombination analysis, we unveiled that the GRV strains represent a novel variant resulting from multiple reassortment events. Specifically, the µNS, λC, and σNS genes of GRV were found to have originated from chicken reovirus, while the σA gene of GRV exhibited a higher degree of similarity with a novel duck reovirus. The remaining genes of GRV were traced back to Muscovy duck reovirus. Collectively, our findings underscore the significance of GRV as a pathogenic agent impacting the goose farming industry. The insights gleaned from this study contribute to a more comprehensive understanding of the epidemiology of GRV in Southern China and shed light on the genetic reassortment events exhibited by the virus.