COVID-19 Incidence and Disease Course Among Patients at an Allergy Department.

Background: Since the coronavirus pandemic in 2020, there is not much reported about the disease course of COVID-19 in patients with allergic diseases. Objectives: The aim of this study was to investigate the cumulative incidence and severity of COVID-19 among patients from the allergy department compared with the general Dutch population and people from their household. Design: We conducted a comparative longitudinal cohort study. Methods: In this study patients of the allergy department were included with their household members as a control group. Data from the beginning of the pandemic were systematically obtained through questionnaires by telephonic interviews and retrieved from electronic patient files between October 15, 2020 and January 29, 2021. Main outcomes were confirmed SARS-CoV-2 infection, disease duration, hospitalization, intensive care admission, and mortality. Questions regarding applied social distancing measures were inventoried as well. Results: Three hundred and eighty nine patients (median age 39.1 (18.7-84.7) years, 69.9% female) and 441 household members (median age 42.0 (18.0-91.5), 44.1% female) were included. The cumulative COVID-19 incidence in patients was higher compared with the general population (10.5% vs 5.6%, P < .001). In total, 41 (10.5%) patients attending the allergy clinic compared to 38 (8.6%) household members were infected with SARS-CoV-2 (P = .407). Median disease duration was 11.0 (0.0-61.0) days in patients compared to 10.5(1.0-232.0) days in household members (P = .996). Conclusion: The cumulative COVID-19 incidence in patients from the allergy cohort was higher compared with the general Dutch population, but similar compared with household members. There was no difference in symptoms, disease duration, or hospitalization rate between the allergy cohort and their household members.

Comparison of Marek's Disease Virus Challenge Strains and Bird Types for Vaccine Licensing.

Marek's disease virus (MDV) is an important poultry pathogen that is controlled through widespread vaccination with avirulent and attenuated strains. However, continued evolution of field viruses to higher virulence has required ongoing improvement of available vaccine strains, and these vaccine strains offer an attractive platform for designing recombinant vector vaccines with cross-protection against MDV and additional pathogens. Recent reports of failures in vaccine licensing trials of positive controls to reach appropriately high levels of Marek's disease incidence prompted us to evaluate possible combinations of outbred specific-pathogen-free layer lines and alternative virulent challenge strains that could provide more consistent models for serotype 3 vectored vaccine development. Choice of layer line and virulent MDV challenge strain each contributed to the ability of a challenge model to reach 80% virulence in unvaccinated positive control groups in the majority of trials, without overwhelming serotype 3 vectored vaccine protection in vaccinated groups. Conversely, reducing challenge virus dose by a factor of four, or vaccine dose by half, had no consistent effect across these models. Although MDV strain 617A had the most potential as an alternative to strains that are currently approved for licensing trials, no combination of layer line and challenge virus consistently met the goals for a successful challenge model in all study replicates, indicating that high variability is an inherent difficulty in MDV challenge studies, at least when outbred birds are used.

Artículo regular­Comparación de las cepas de desafío del virus de la enfermedad de Marek y los tipos de aves para la obtención de licencias de vacunas. El virus de la enfermedad de Marek (MDV) es un patógeno importante en la avicultura que se controla mediante la vacunación generalizada con cepas avirulentas y atenuadas. Sin embargo, la evolución continua de los virus de campo hacia una mayor virulencia ha requerido una mejora continua de las cepas vacunales disponibles y estas cepas vacunales ofrecen una plataforma atractiva para diseñar vacunas con vectores recombinantes que induzcan protección cruzada contra el virus de la enfermedad de Marek y patógenos adicionales. Los reportes recientes de fallas en los controles positivos para alcanzar niveles apropiadamente altos de incidencia de la enfermedad de Marek en los ensayos para obtener la licencia de vacunas llevaron a evaluar posibles combinaciones de líneas de postura híbridas libres de patógenos específicos y cepas de desafío virulentas alternativas que podrían proporcionar modelos más consistentes para el desarrollo de vacunas con vectores de serotipo 3. Tanto la elección de la línea de postura como de la cepa de desafío virulenta de Marek contribuyeron a obtener un modelo de desafío con capacidad para alcanzar el 80% de virulencia en grupos controles positivo no vacunados en la mayoría de los ensayos, sin una protección abrumadora de la vacuna con vector de serotipo 3 en los grupos vacunados. Por el contrario, la reducción de la dosis del virus de desafío en un factor de cuatro, o la dosis de vacuna a la mitad, no tuvieron un efecto constante en estos modelos. Aunque la cepa 617A de Marek mostró el mayor potencial como alternativa a las cepas que actualmente están aprobadas para ensayos de licenciar vacunas, ninguna combinación de línea de postura y virus de desafío cumplió consistentemente los objetivos de un modelo de desafío exitoso en todas las réplicas del estudio, lo que indica que la alta variabilidad es una dificultad inherente en los estudios de desafío para la enfermedad de Marek, al menos cuando se utilizan aves híbridas.

Evaluation of Protective Efficacy When Combining Turkey Herpesvirus-Vector Vaccines.

Turkey herpesvirus (HVT) is widely used as a vaccine against Marek's disease in chickens and recently as a vector for foreign genes from infectious bursal disease virus, Newcastle disease (ND) virus, infectious laryngotracheitis (ILT) virus, and avian influenza virus. Advantages of HVT-vector vaccines are that the vaccines do not contain live respiratory viruses or live infectious bursal disease virus able to replicate and cause disease or embryo mortality, they can be administered at hatch or in ovo, and they are relatively insensitive to interference from maternally derived antibodies. As producers have tried to combine HVT-vector vaccines to protect against additional diseases, reports have indicated that applying two vectored vaccines using the same HVT vector is reported to reduce the efficacy of one or both vaccines. To confirm this interference, we evaluated commercial vaccines from multiple companies, including products with inserts designed to protect against ND, infectious ILT, and infectious bursal disease (IBD). Using a standard dosage, we found that the ILT product was most severely affected by the addition of other vaccines, as demonstrated by a significant increase in clinical signs, significant decrease in weight gain, and increase in quantity of challenge virus observed from tracheal swabs collected from Days 3-5 postchallenge. The ND and IBD products were also affected by the addition of other vaccines, although in most cases differences compared to vaccination with the vector alone were not statistically significant. This study demonstrates the importance of following manufacturer guidelines and the need for validating alternative strategies to benefit from the high level of protection offered by vector vaccines.

Evaluación de la eficacia de la protección cuando se combinan vacunas recombinantes con base en el virus herpes del pavo como vector. El virus herpes de los pavos (HVT) se usa ampliamente como una vacuna contra la enfermedad de Marek en pollos y recientemente como un vector para genes externos como del virus de la enfermedad infecciosa de la bolsa, del virus de la enfermedad de Newcastle (ND), del virus de la laringotraqueítis infecciosa (ILT) y del virus de la influenza aviar. Las ventajas de las vacunas con vector de HVT consisten en que las vacunas no contienen virus vivos respiratorios o virus de la enfermedad infecciosa de la bolsa, no son capaces de replicarse y causar enfermedad o mortalidad embrionaria, pueden administrarse en el momento de la eclosión o in ovo y son relativamente insensibles a la interferencia de anticuerpos de origen materno. A medida que los productores han intentado combinar las vacunas con el vector HVT para inducir protección contra enfermedades adicionales, los informes han indicado que la aplicación de dos vacunas vectorizadas utilizando el mismo vector HVT reduce la eficacia de una o de ambas vacunas. Para confirmar esta interferencia, se evaluaron las vacunas comerciales de múltiples compañías, incluidos los productos con inserciones diseñadas para proteger contra la enfermedad de Newcastle, la laringotraqueítis infecciosa aviar y contra la enfermedad infecciosa de la bolsa. Utilizando una dosis estándar, se encontró que el producto para la laringotraqueítis infecciosa se vio más afectado por la adición de otras vacunas, como lo demuestra un aumento significativo en los signos clínicos, una disminución significativa en el aumento de peso y un aumento en la cantidad de virus de desafío observados en los hisopos traqueales recolectados de tres a cinco días después del desafío. Los productos para la enfermedad de Newcastle y para la enfermedad de Gumboro también se vieron afectados por la adición de otras vacunas, aunque en la mayoría de los casos las diferencias en comparación con la vacunación únicamente con el vector no fueron estadísticamente significativas. Este estudio demuestra la importancia de seguir las pautas del fabricante y la necesidad de validar estrategias alternativas para beneficiarse del alto nivel de protección ofrecido por las vacunas con vectores.

Repeatability of Three-Dimensional Computed Tomographic Volumetric Measurement of Lumbosacral Intervertebral Foramina in German Shepherd Dogs.

OBJECTIVES: This article determines the repeatability of a recently reported method of volumetric measurement of the lateral intervertebral neurovascular foramina at the lumbosacral junction in German shepherd dogs. MATERIALS AND METHODS: Batch files including the intervertebral neurovascular foramina were derived from previously obtained computed tomography studies of the extended lumbosacral junction of 20 German shepherd dogs and converted into volume datasets. Three observers independently performed five measurements of the left and right lumbosacral intervertebral neurovascular foramina in each dog, using an Extended Brilliance Workstation (Phillips, The Netherlands) to generate a volume of the lumbosacral intervertebral foramina in cubic millimetres, as described by Worth and colleagues in 2017. The inter-observer repeatability of the mean of the five-volume measurements (40 foramina) was assessed using the Bland-Altman limits of agreement method. One observer, blinded to the previous measurements, repeated the volumetric analysis on 20 lumbosacral intervertebral foramina for an assessment of intra-observer repeatability using the same statistical methods. RESULTS: This method of volumetric analysis showed good intra- and inter-observer repeatability with 95% of paired comparisons falling within two standard deviations of the mean difference between them. CLINICAL SIGNIFICANCE: This method of measuring the volume of the lumbosacral intervertebral neurovascular foramina is repeatedly reliable and may be a useful tool when testing the effects of motion and disease on the lumbosacral junction, and could help guide surgical intervention when foraminal narrowing is implicated in the clinical signs.

Evaluation of the rostral projection of the sacral lamina as a component of degenerative lumbosacral stenosis in German shepherd dogs.

OBJECTIVE: To determine the association between a greater rostral projection of the sacral lamina and clinical signs of cauda equina syndrome (CES) in German shepherd dogs (GSD) with presumptive degenerative lumbosacral disease (DLSS). STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: One hundred forty-three GSD (125 police dogs and 18 pet dogs) presenting for either CES or prebreeding evaluation. Fifty-five were classified as affected by CES and diagnosed with DLSS, and 88 were classified as unaffected on the basis of clinical and imaging findings. METHODS: The position of the rostral edge of the sacral lamina was measured from radiographs and/or computed tomography (CT) scans. This position was compared between affected and unaffected dogs. In dogs that underwent both radiography and CT scanning, the agreement between sacral lamina localization using each imaging modality was determined. Owners/handlers were contacted to determine whether dogs subsequently developed clinical signs compatible with CES at a mean of 29 months (unaffected). RESULTS: The sacral lamina did not extend as far rostrally in affected dogs, compared to unaffected dogs (P = .04). Among the 88 dogs unaffected by CES at initial evaluation, 2 developed clinical signs consistent with CES at follow-up. CONCLUSION: Rostral projection of the sacral lamina, previously proposed as a potential risk factor in dogs with CES due to lumbosacral degeneration, was not associated with a diagnosis of DLSS in this study; the opposite was true. CLINICAL SIGNIFICANCE: Rostral projection of the sacral lamina may not be a predisposing factor in the development of CES due to DLSS in GSD.

Medium-Term Outcome and CT Assessment of Lateral Foraminotomy at the Lumbosacral Junction in Dogs with Degenerative Lumbosacral Stenosis.

OBJECTIVE: This article aims to report the medium-term clinical outcome and assess persistence of enlargement of the lumbosacral lateral intervertebral neurovascular foramen using computed tomography (CT) volumetric analysis in dogs following lateral foraminotomy. MATERIALS: Six dogs that underwent lumbosacral lateral foraminotomy on one or both sides were evaluated with CT prior to, immediately postoperatively (n = 2) and at 12 to 44 months of follow-up. Five out of six dogs had successful clinical outcomes with alleviation of pain and increased levels of activity, according to subjective assessment. Immediate postoperative CT volumetric analysis of the lateral intervertebral neurovascular foramina in two dogs indicated a 650 to 800% increase in volume in extension achieved by foraminotomy (four foramens). At subsequent follow-up, bone regrowth had occurred with reduction in foraminal volume, though in both dogs foraminal volume remained higher than preoperative values. Follow-up CT at a median of 24 months postoperatively indicated a mean 335% increase in volume of the lumbosacral lateral intervertebral neurovascular foramina in extension compared with the preoperative foraminal volume. The follow-up volume was substantially greater than the presurgical volume in four out of six dogs. CLINICAL SIGNIFICANCE: In this limited case series, lateral foraminotomy achieved persistent enlargement of the lumbosacral lateral intervertebral neurovascular foramen in the medium term, but osseous regrowth at the site was demonstrated which may limit the effectiveness of lateral foraminotomy in the longer term. One of two working dogs had recurrent clinical signs that necessitated further surgery.

Effect of dorsal laminectomy and dorsal annulectomy with partial lumbosacral discectomy on the volume of the lateral intervertebral neuroforamina in dogs when the lumbosacral junction is extended.

OBJECTIVE: To determine the effect of dorsal annulectomy and partial discectomy on the volume of the lumbosacral lateral intervertebral neurovascular foramina (intervertebral foramina) in canine cadavers during extension of the lumbosacral junction. STUDY DESIGN: Ex vivo experiment. SAMPLE POPULATION: Lumbosacral specimens from 10 large breed dogs euthanatized for reasons unrelated to lumbosacral disease. METHODS: The lumbosacral specimens were clamped in a wooden jig and scanned using computed tomography (CT) with the lumbosacral junction in a neutral position and loaded in extension using a tensioning device. The 3-dimensional volumes of the lumbosacral intervertebral neurovascular foramina were measured and the extent of any disc degeneration was determined from the CT data. A limited dorsal laminectomy of S1 and a dorsal LS annulectomy and partial discectomy were then performed. The lumbosacral specimens were remounted into the jig and loaded into extension at the same tension and were re-scanned. Measurements of intervertebral foraminal volume were then repeated. RESULTS: The mean volume of the lumbosacral foramina (n = 20) was 381 mm3 in neutral (unloaded) positioning and 137 mm3 when loaded in extension. Following dorsal annulectomy, the mean volume was significantly reduced by a mean of 28% to 98 mm3 (P < .01). The foraminal volume was reduced in 19/20 lumbosacral foramen, with the post-annulectomy volume ranging from 31% to 97% of the pre-annulectomy volume (3%-69% reduction). CONCLUSIONS: This study suggests that a dorsal annulectomy with partial discectomy may induce further dynamic collapse of the lumbosacral articulation in the dog.

Computed tomographic evaluation of dynamic alteration of the canine lumbosacral intervertebral neurovascular foramina.

OBJECTIVE: To develop a computed tomographic (CT) method to measure the volume of the lumbosacral intervertebral neurovascular foramina (IVF) in dogs, and determine the effect of the range of motion of the lumbosacral (LS) junction on this measurement in German shepherd dogs (GSDs) with degenerative lumbosacral stenosis (DLSS) compared to unaffected controls. STUDY DESIGN: In vivo analysis and retrospective case series. SAMPLE POPULATION: Twenty-four working Police GSDs, 12 diagnosed with DLSS and 12 unaffected by DLSS were compared to 10 Greyhounds without DLSS. METHODS: Three-dimensional renderings of CT data were used to measure the lumbosacral foraminal volume of dogs positioned in dorsal recumbency with the LS junction alternately positioned in extension, neutral position, and flexion. RESULTS: Volumetric analysis of the IVF was found repeatable for the extended and neutral positions (interclass correlation coefficient of 0.89 and 0.8, respectively). The mean lumbosacral IVF volume was decreased by 74% between LS flexion and extension in Greyhounds, compared to 79 and 85% reductions in GSDs unaffected and affected by DLSS, respectively. The lumbosacral IVF volume was decreased by 23% when comparing extended to neutral LS positions in Greyhounds, 29% in unaffected GSDs, and 31% in affected GSDs. IVF volumes were smaller in affected GSDs compared to unaffected GSDs (P < .05) and Greyhounds (P < .01). CONCLUSIONS: Positioning the LS junction in full extension decreases the volume of the lumbosacral IVF. This dynamic narrowing was more pronounced in GSDs with signs of DLSS than in GSDs not overtly affected by DLSS.

ACCURACY OF RADIOGRAPHIC DETECTION OF THE CRANIAL MARGIN OF THE DORSAL LAMINA OF THE CANINE SACRUM.

An elongated sacral lamina has been described as one of the contributing factors for dogs with cauda equina syndrome due to degenerative lumbosacral stenosis (DLSS); however, published evidence is lacking on the accuracy of radiographic screening for the presence of this lesion. Objectives of this prospective, cross-sectional cadaver study were to describe the accuracy and repeatability of detection of the cranial sacral lamina margin on plain lateral radiographs of the lumbosacral junction in dogs. Twenty-five medium and large breed canine cadavers were radiographed before and after placement of a radiopaque hook in the cranial margin of the sacral lamina. Three independent evaluators placed digital markers at the perceived margin on preinterventional radiographs. The distance from perceived location to the true location on postinterventional radiographs was recorded for each dog and observer. A discordance threshold (distance between perceived and actual margin) of 1.5 mm was subjectively defined as clinically relevant. The three evaluators demonstrated good repeatability, although the accuracy for margin detection was only fair (mean discordance 1.7 mm). Evaluators demonstrated greater accuracy in identifying the landmark in juveniles (1.4 mm) vs. adults (1.8 mm; P < 0.01). Results of this study indicated that observer repeatability is good and accuracy is fair for correctly identifying the radiographic cranial margin of the sacral lamina in dogs. This should be taken into consideration when interpreting elongation of the sacral lamina in radiographs of dogs with suspected DLSS, especially adults.

Temperature-Sensitive Salmonella enterica Serovar Enteritidis PT13a Expressing Essential Proteins of Psychrophilic Bacteria.

Synthetic genes based on deduced amino acid sequences of the NAD-dependent DNA ligase (ligA) and CTP synthetase (pyrG) of psychrophilic bacteria were substituted for their native homologues in the genome of Salmonella enterica serovar Enteritidis phage type 13a (PT13a). The resulting strains were rendered temperature sensitive (TS) and did not revert to temperature resistance at a detectable level. At permissive temperatures, TS strains grew like the parental strain in broth medium and in macrophage-like cells, but their growth was slowed or stopped when they were shifted to a restrictive temperature. When injected into BALB/c mice at the base of the tail, representing a cool site of the body, the strains with restrictive temperatures of 37, 38.5, and 39°C persisted for less than 1 day, 4 to 7 days, and 20 to 28 days, respectively. The wild-type strain persisted at the site of inoculation for at least 28 days. The wild-type strain, but not the TS strains, was also found in spleen-plus-liver homogenates within 1 day of inoculation of the tail and was detectable in these organs for at least 28 days. Intramuscular vaccination of White Leghorn chickens with the PT13a strain carrying the psychrophilic pyrG gene provided some protection against colonization of the reproductive tract and induced an anti-S. enterica antibody response.

Computed tomographic method for measurement of inclination angles and motion of the sacroiliac joints in German Shepherd Dogs and Greyhounds.

OBJECTIVE: To develop an in vivo CT method to measure inclination angles and motion of the sacroiliac joints in dogs of performance breeds. ANIMALS: 10 German Shepherd Dogs and 12 Greyhounds without signs of lumbosacral region pain or neurologic problems. PROCEDURES: CT of the ilium and sacrum was performed in flexed, neutral, and extended hind limb positions. Lines were drawn on volume-rendered images acquired in the flexed and extended positions to measure motion of the ilia relative to the sacra. Inclination angles of the synovial and ligamentous components of the sacroiliac joints were measured on transverse-plane CT images acquired at cranial and caudal locations. Coefficients of variance of measurements were calculated to determine intraobserver variability. RESULTS: Coefficients of variance of measurements ranged from 0.17% to 2.45%. A significantly higher amount of sacroiliac joint rotational motion was detected for German Shepherd Dogs versus Greyhounds. The cranial synovial joint component had a significantly more sagittal orientation in German Shepherd Dogs versus Greyhounds. No significant differences were detected between breeds for x- or y-axis translational motion or caudal synovial or ligamentous joint component inclination angles. CONCLUSIONS AND CLINICAL RELEVANCE: The small amounts of sacroiliac joint motion detected in this study may buffer high-frequency vibrations during movement of dogs. Differences detected between breeds may be associated with the predisposition of German Shepherd Dogs to develop lumbosacral region signs of pain, although the biological importance of this finding was not determined. Future studies are warranted to compare sacroiliac joint variables between German Shepherd Dogs with and without lumbosacral region signs of pain.

Comparison between a novel bovine xenoimplant and autogenous cancellous bone graft in tibial tuberosity advancement.

OBJECTIVE: To compare radiographic healing and clinical outcome of a frontal-opening wedge osteotomy of canine tibiae when the osteotomy site is packed with either a novel bovine xenograft or standard autogenous cancellous bone graft (ACBG). STUDY DESIGN: Cohort study. ANIMALS: Dogs (n = 82) with partial or complete rupture of the cranial cruciate ligament that had tibial tuberosity advancement (TTA). METHODS: In 48 dogs, the osteotomy was packed with a novel bovine xenograft and in 34 dogs, ACBG was used. Eight week postoperative radiographs from both groups were graded for osteotomy healing using a 0-4-point scale. Data were analyzed using a Mann-Whitney test with significance set at P < .05. RESULTS: Thirty-four dogs (39 stifles) with xenoimplants had complete records and radiographic follow-up at 8 weeks. No significant differences between xenografting and autografting were identified in grading of osteotomy fill, osteointegration, or healing of the distal osteotomy. Significant differences were noted in grading of osteotomy healing proximally (autograft > xenoimplant) and of opacity in the osteotomy site (xenoimplant > autograft). CONCLUSIONS: Radiographic evidence of healing of the xenoimplanted portion of the TTA osteotomy was equivalent to results with ACBG. Healing of the proximal osteotomy site (above the cage) was improved when ACBG was used as the graft.

Bilateral carpal valgus deformity in hand-reared cheetah cubs (Acinonyx jubatus).

Four hand-reared cheetah cubs (Acinonyx jubatus) exhibited progressively severe bilateral valgus deformity of the carpi (CV) during the weaning period. Radiographs of the thoracic limbs suggested normal bone ossification, and serum chemistry was unremarkable. All affected cubs developed CV shortly after the onset of gastroenteritis, which was treated medically, and included use of a prescription diet. A sudden decrease in growth rate was associated with gastrointestinal disease. Before gastroenteritis and CV, affected cubs had higher growth rates than unaffected cubs, despite similar mean daily energy intake. Return to normal thoracic limb conformation was consequent to dietary manipulation (including a reduction in energy intake and vitamin and mineral supplementation), as well as decreased growth rates and recovery from gastroenteritis. The cause of the CV is likely to have been multi-factorial with potentially complex physiological interactions involved.