This report describes an outbreak of type C botulism in two organic, free-range commercial layer farms in the Midwest. Hens affected were 64-wk-old Hy-Line brown hens and 34-wk-old Hy-Line brown hens owned by the same company, but housed on different premises, with approximately 20,000 birds per house. Mortality over the 2 wk of investigation was estimated to be up to 8% and 2.8%, respectively, with birds acting listless, lethargic, and depressed. Clinical signs consisted of progressive paralysis, and severely affected birds were moribund and laterally recumbent. Hens had ruffled feathers that easily epilated, with loss of muscular tone in the neck, tail, and wings. Hens had closed eyes and were reluctant to move. There were no significant gross or histopathologic lesions. Intestinal samples were submitted to the University of Pennsylvania Botulism Diagnostic Laboratory for real-time PCR and were positive for Clostridium botulinum organisms containing the Type C neurotoxin gene. Speculations on the source of the botulinum toxins include poor mortality removal leading to cannibalism of decomposing carcasses, as well as birds on the farm having access to putrid carcasses in the compost pile from a hole in their outdoor access fence. Reporte de caso- Brote de botulismo tipo C en gallinas ponedoras comerciales. Este informe describe un brote de botulismo tipo C en dos granjas de ponedoras comerciales orgánicas en el medio oeste. Las gallinas afectadas tenían 64 semanas de edad de la línea Hy-Line marrón y gallinas de 34 semanas de edad Hy-Line marrón propiedad de la misma empresa, pero alojados en diferentes lugares, con aproximadamente el 20 000 aves por caseta. La mortalidad alrededor de la segunda semana de investigación se estimó fue de hasta 8% y 2.8%, respectivamente, con aves apáticas, letárgicas y deprimidas. Los signos clínicos consistieron en parálisis progresiva y las aves severamente afectadas estaban moribundas y reclinada lateralmente. Las gallinas tenían plumas erizadas que se desprendían fácilmente, con pérdida del tono muscular en el cuello, la cola y en las alas. Las gallinas tenían los ojos cerrados y se rehusaban a moverse. No hubo lesiones macroscópicas o histopatológicas significativas. Se enviaron muestras intestinales al Laboratorio de Diagnóstico de Botulismo de la Universidad de Pennsylvania para análisis por PCR en tiempo real y fueron positivas para Clostridium botulinum que contenían el gene de la neurotoxina tipo C. Se especula que el origen de las toxinas botulínicas son la mala eliminación de la mortalidad que lleva al canibalismo de los cadáveres en descomposición, así como las aves en la granja que tienen acceso a los cadáveres putrefactos en la pila de compostaje a través de un agujero en la rejilla de acceso al exterior.

Avian reovirus (ARV) has emerged as an important pathogen in turkeys, causing economic losses through tenosynovitis, necrotizing hepatitis, immunosuppression, and enteric disease. Despite its ubiquity, the evolutionary history of ARV cross-species transmission among chickens, turkeys, and wild birds remains poorly understood, hindering effective control and surveillance. This study investigates ARV temporal phylogenetics with an emphasis on interspecies transmission in turkeys. Whole genome sequences (WGSs) from seventy-seven turkey cases and one quail case at the Iowa State University Veterinary Diagnostic Laboratory, along with 74–136 segment sequences per gene from GenBank (1970–2023), were analyzed. Temporal phylogenetic analyses identified chickens as the ancestral host, with spillover into turkeys beginning in the mid-20th century, followed by stable transmission within turkey populations. Migration analyses revealed predominantly unidirectional transmission from chickens to turkeys. WGS analyses showed high variability in the M2 and σC-encoding region of the S1 segment, suggesting selective pressure on outer capsid proteins. M2, S1 σC, and L3 had the highest substitution rates, implicating their role in adaptation and antigenic diversity. These findings highlight the complexity of ARV evolution across hosts and underscore the need for robust genotyping schemes and surveillance strategies to mitigate outbreaks in poultry.

Ornithobacterium rhinotracheale (ORT) has been associated with poultry respiratory disease worldwide. The organism is fastidious and isolation is challenging. One TaqMan real-time PCR (qPCR) assay has been developed for the detection of ORT. However, during validating the ORT qPCR, the assay performance was suboptimal. During the in silico evaluation, deviations from the basic parameters for primers and probes designs (e.g., presence of stable undesirable primer-dimers) were observed. The suboptimal design led to low efficiency and low sensitivity of the assay. Initially, modification on the probe was carried out to improve the performance of the assay. However, the assay’s performance (efficiency and sensitivity) was still suboptimal. In this manuscript, we describe the development of a new qPCR assay and the comparison of its performance with the currently available assay. A highly efficient, sensitive, and specific qPCR assay was developed with approximately 1000-folds reduction in the limit of detection (from 3 × 10⁶ plasmid DNA copies/mL to 1 × 10³ plasmid DNA copies/mL). Additionally, the efficiency of the new assay (E = 98.70%) was significantly better than the current assay (E = 73.18%). The newly developed assay is an improved diagnostic tool for the sensitive and efficient diagnosis of ORT from clinical samples.

The US poultry industry suffers significant economic losses due to Avian Reovirus (ARV) infections, which mainly cause arthritis/tenosynovitis in turkeys and chickens. The emergence of outbreaks since 2012 highlights the urgent need for improved epidemiological tools. Given the distinct evolutionary history of each segment of the virus and limited resolution of existing typing methods for ARV based on a single gene, a novel genotyping scheme was developed utilizing a constellation-based genotyping approach to enhance source tracing and control strategies especially for ARV in turkeys. A dataset of 199 ARV sequences from turkey hosts was curated and organized based on branch distances from maximum likelihood phylogenetic trees using TreeCluster. The grouping performance was evaluated and optimized according to established criteria described in this study. The proposed methods selected the M2, S1 σC-encoding region, and L3 genomic segments due to their non-random reassortment and biological significance. The novel scheme identified 8 major genotypes and revealed clear epidemiological links between turkey breeder and meat-type farms, as well as common shared sources among different meat-type farms, suggesting both vertical and horizontal transmission pathways. Additionally, reassortment events were detected using our novel typing scheme, highlighting the complex evolutionary dynamics of ARV. By correlating genotypic patterns with epidemiological data, this study provides a foundation for improved ARV monitoring and disease management.

Bordetella avium (BA) is one of many pathogens that cause respiratory diseases in turkeys. However, other bacterial species can easily overgrow it during isolation attempts. This makes confirming the diagnosis of BA as the causative agent of turkey coryza more difficult. Currently, there are two PCR assays for the molecular detection of BA. One is conventional gel-based PCR and the other is TaqMan real-time PCR (qPCR) assay. However, multiple pitfalls were detected in both assays regarding their specificity, sensitivity, and efficiency, which limits their utility as diagnostic tools. In this study, we developed and validated two TaqMan qPCR assays and compared their performance to the currently available TaqMan qPCR. The two assays were able to correctly identify all BA isolates and showed negative results against a wide range of different microorganisms. The two assays were found to have high efficiency with a detection limit of approximately 1 × 10³ plasmid DNA Copies/mL with high repeatability and reproducibility. In comparison to the currently available TaqMan qPCR assay, the newly developed assays showed significantly higher PCR efficiencies due to superior primers and probes design. The new assays can serve as a reliable tool for the sensitive, specific, and efficient diagnosis of BA.

Blood gas and biochemistry reference intervals were established for 3 genetically distinct commercial varieties (CVs) of Hy-Line laying hens: 2 brown