Licensing Requirements for Poultry Veterinary Biologics in the United States.

The use of veterinary biologicals is an integral component of poultry health programs. All veterinary biologicals are licensed and sold by manufacturing firms under strict regulation by the U.S. Department of Agriculture to ensure purity, potency, efficacy, and safety of the product. The licensing process for a new vaccine is a complex process involving a defined set of studies for each type of vaccine that are performed by the biologics firm, according to approved protocols, with results submitted to the Center for Veterinary Biologics for review. There are 10 classifications of veterinary biologicals and four types of licenses. Manufacturing and testing procedures are also defined within the licensing process. Licensing requirements were initially codified into law. In addition, guidance documents in the form of memoranda and notices have been published to address licensing for additional classes of vaccines and disease agents. This overview of vaccine licensure in the United States is offered to provide a better understanding of the process, the participants, and the factors that influence the time required to produce a commercial product.

Estudio recapitulativo- Requisitos de licencia para productos biológicos veterinarios avícolas en los Estados Unidos. El uso de productos biológicos veterinarios es un componente integral de los programas de salud avícola. Todos los productos biológicos veterinarios están autorizados y son vendidos por empresas fabricantes bajo estricta regulación del Departamento de Agricultura de los Estados Unidos para garantizar la pureza, potencia, eficacia y seguridad del producto. El proceso de concesión de licencia para una nueva vacuna es un proceso complejo que implica un conjunto definido de estudios para cada tipo de vacuna que son llevados a cabo por la empresa productora de biológicos, según protocolos aprobados y los resultados se envían al Centro de Productos Biológicos Veterinarios para su revisión. Existen 10 clasificaciones de biológicos veterinarios y cuatro tipos de licencias. Los procedimientos de fabricación y de prueba también se definen dentro del proceso de concesión de licencias. Los requisitos para la concesión de licencias se codificaron inicialmente como ley. Además, se han publicado documentos de orientación en forma de memorandos y avisos que han sido publicados para abordar la concesión de licencias para clases adicionales de vacunas y agentes patógenos. Esta revisión de los procesos de licencia de vacunas en los Estados Unidos se ofrece para brindar una mejor comprensión del proceso, los participantes y los factores que influyen en el tiempo necesario para producir un producto comercial.

Polymerase chain reaction-based identity assay for pathogenic turkey Eimeria.

Diagnosis of turkey Eimeria infection by conventional parasitologic methods is challenging and, until now, no molecular tools existed that clearly distinguished the four widely recognized pathogenic species: Eimeria adenoeides, E. meleagrimitis, E. gallopavonis, and E. dispersa. In this study, the internal transcribed spacer region one (ITS-1) was amplified and sequenced from 23 conventionally characterized reference samples. Phylogenic analysis segregated samples into five distinct cluster groups. The ITS-1 region(s) within each cluster were of a particular length and shared from 96% to 100% identity, while amplified ITS-1 region(s) between clusters differed in length and shared only 10.6% to 49.7% sequence identity. In addition, we developed PCR primer sets as diagnostic tools capable of specifically identifying members of each of the five clusters.

A Field Study of Histologic and Bacteriologic Characterization of Femoral Head Separation and Femoral Head Necrosis.

Histologic and bacteriologic features for groups of average 31-day-old broilers displaying three gross categories of femoral head alterations were documented. Categories included simple femoral head separation (FHS), femoral head transitional changes (FHT), and femoral head necrosis (FHN). Groups with grossly normal (NORM) femoral heads and cull birds with FHN and having gross signs of sepsis (Cull-FHN) were also included in the study. There was a 10% occurrence of positive bacterial cultures for all birds tested. Most positive cultures (33%) were found in the Cull-FHN group, while only a 12% occurrence was seen in the FHS group, and no positives were present in the FHT or FHN groups. A 14% total occurrence of femoral bacterial chondronecrosis with osteomyelitis or simple osteomyelitis (BCO-O) was observed. A progressive increase in the prevalence of BCO-O was apparent between groups going from NORM (0%), FHS (4%), FHT (14%), FHN (13%), and reaching a maximum of 67% in the Cull-FHN group. Minimal to mild femoral head cartilage necrosis was present in 40% of NORM broilers and 100% of the FHS, FHT, and FHN groups, but at moderate severity in 20% of the Cull-FHN group. Thus, the majority of FHN cases were associated with aseptic cartilage necrosis rather than BCO-O. These findings suggest that aseptic cartilage necrosis may be as important as septic necrosis as a cause of gross femoral head disease. A 26% overall occurrence was seen for hip synovitis-arthritis, but group differences were not statistically significant. Synovitis was not seen in the NORM group and was present in some (12%) of the FHS group but was observed at a high rate in both the FHN (43%) and the Cull-FHN (50%) groups. Morphometric measurements demonstrated that the area size of femoral fibrous cortical defects or "cutback zones" were generally larger for all gross categories relative to NORM, with a significant difference between NORM and FHS groups. This study underscores the multifactorial etiology of FHN and the importance of conducting both histologic and bacteriologic evaluations in which gross evidence of FHN or BCO-O occurs.