Characterization of an Outbreak of Infectious Coryza (Avibacterium paragallinarum) in Commercial Chickens in Central California.

In 2017, the Turlock branch of the California Animal Health & Food Safety laboratory system received a significant increase in infectious coryza (IC) necropsy cases, with a total of 54 submissions originating from commercial broilers (n = 40), commercial layers (n = 11), and backyard chickens (n = 3). Layer flocks positive for IC were distributed within the adjacent counties of Merced and Stanislaus, while broiler flocks were concentrated within Merced County. The backyard flocks were located in Alameda and Sacramento counties. The clinical and pathologic presentation was consistent with IC, although septicemic lesions were also noticed. Avibacterium paragallinarum was isolated and identified by PCR from the respiratory tract as well as from extrarespiratory sites. Polymicrobial infections involving other viral (infectious bronchitis virus, infectious bursal disease virus) and bacterial (Mycoplasma spp., Escherichia coli, Ornithobacterium rhinotracheale, Gallibacterium anatis biovar haemolytica) agents were commonly reported. Thirteen selected Av. paragallinarum isolates were successfully characterized as serovar C (Page scheme) and serovar C2 (Kume scheme). They shared a unique enterobacterial repetitive intergenic consensus (ERIC) PCR, differing from the four reference strains, and showed consistent high minimum inhibitory concentration values for tetracycline, suggesting a common origin from a single clone. Based on these results, high biosecurity standards and proper immunization of susceptible, multi-age flocks should always be implemented and adjusted as needed. The importance of backyard flocks should not be underestimated due to their unique epidemiologic role.

Caracterización de un brote de coriza infecciosa (Avibacterium paragallinarum) en pollos comerciales en la parte central de California. En el año 2017, la sede en Turlock del Sistema de Laboratorios de Salud Animal y Seguridad Alimentaria de California recibió un aumento significativo en el número de casos de necropsia por coriza infecciosa, con un total de 54 casos, incluyendo casos provenientes de pollos de engorde comerciales (n = 40), gallinas de postura comerciales (n = 11) y aves de traspatio (n = 3). Las parvadas de gallinas de postura positivas para coriza infecciosa se distribuyeron en los condados adyacentes de Merced y Stanislaus, mientras que las parvadas de pollos de engorde se concentraron en el condado de Merced. Las parvadas de traspatio estaban ubicadas en los condados de Alameda y Sacramento. La presentación clínica y patológica fue consistente con coriza infecciosa, aunque también se observaron lesiones septicémicas. Se aisló Avibacterium paragallinarum y se identificó mediante PCR en el tracto respiratorio y también de sitios extrarespiratorios. Las infecciones polimicrobianas relacionadas con otros virus (virus de la bronquitis infecciosa, virus de la enfermedad infecciosa de la bolsa) y bacterias (Mycoplasma spp., Escherichia coli, Ornithobacterium rhinotracheale, Gallibacterium anatis biovar haemolytica) fueron reportadas comúnmente. Trece aislamientos seleccionados de A. paragalinarum se caracterizaron con éxito como serovar C (esquema de Page) y serovar C2 (esquema de Kume). Estos aislamientos Compartieron por PCR un consenso intergénico repetitivo enterobacterial (ERIC) único, que difiere de las cuatro cepas de referencia y mostraron valores constantes de concentración mínima inhibitoria alta para tetraciclina, lo que sugiere un origen común de un solo clon. Con base en estos resultados, siempre se deben implementar y ajustar estándares de bioseguridad altos y la inmunización adecuada de parvadas susceptibles de edades múltiples, según sea necesario. La importancia de las parvadas de traspatio no debe subestimarse debido a su función epidemiológica especial.

Historical, spatial, temporal, and time-space epidemiology of very virulent infectious bursal disease in California: a retrospective study 2008-2011.

In December of 2008 very virulent infectious bursal disease virus (vvIBDV) was identified in a commercial flock in northern California. Since then several other backyard and commercial facilities in California have had flocks affected by the same strain and other unique (previously unseen) strains of IBDV. Previous to this incident, very virulent infectious bursal disease (vvIBD) had never been identified in North America. Following the initial outbreak in 2008, California became the first state to undertake a voluntary surveillance effort to try to determine the geographical prevalence of vvIBD based on sequencing of a portion of the segment A region of the vvIBDV genome. To date we have complete geographical information on approximately 500 separate accessions representing approximately 1500 birds from over 200 commercial (-85% of the facilities) and backyard facilities (-15% of the facilities) throughout the state. Sequencing of targeted regions of both the segment A and segment B regions of the genome has revealed three distinct types of IBDV in California chickens. One type is genetically and in pathogenically consistent with vvIBDV. The second and third types only have a segment A region consistent with vvIBDV. Geographic information system mapping coupled with spatial-temporal cluster analysis identified significant spatial and time-space clustering; however, no temporal clustering was noted. The lack of temporal clustering coupled with negative vvIBDV results in tested avian wildlife implies that avian wildlife in California do not currently appear to play a significant role in vvIBDV transmission. In the voluntary surveillance that was done in the Central Valley of California, which has a high density of commercial poultry, no positive farms were found when 142 of 504 farms were sampled. Given this level of sampling, the confidence (probability) of detecting an affected commercial flock was calculated to be between 28% and 81% depending on whether one or five hypothetically affected farms were affected.

Descriptive study of California egg layer premises and analysis of risk factors for Salmonella enterica serotype enteritidis as characterized by manure drag swabs.

This cross-sectional, double-blind study reports the prevalence of Salmonella enterica serotype enteritidis (SE) on California egg layer premises using single vs. pooled manure drag swabs and presents a description of egg production and management systems in the state and an initial analysis of risk factors for SE. The study included 91% of all known eligible egg premises in California, representing the majority of eggs produced in the state. The overall prevalence of SE on California egg layer premises was 10.5%, while 1.1% of all rows sampled were positive for SE. The percentage of positive rows for SE on any premises never exceeded 25% of the 16 swabs collected per premises. A description of egg production and management on California egg layer premises is presented. Statistically significant associations for SE were not evident and were limited because of sample size and the low prevalence of SE on California egg layer premises. Several biological and management factors, such as flock health, stage of production, manure management, ventilation, and watering systems, show trend associations with premises positive for SE and require further investigation. Manure drag swabs serve as a useful tool to validate the core components of an egg quality assurance program for SE based on process control principles.

The occurrence and distribution of Salmonella enteritidis and other serovars on California egg laying premises: a comparison of two sampling methods and two culturing techniques.

Between the summer of 1998 and the winter of 2000, Salmonella analysis was performed on 2128 single and 532 pooled manure drag swabs obtained from 133 California commercial egg laying farms. The isolation of Salmonella from all rows and from all flocks using single or pooled swabs was 80% and 92%, respectively. Hence, there was no statistical difference between single vs. pooled swabs in terms of identifying Salmonella on a row or flock basis. A total of 14 serogroups comprising 44 serotypes were isolated from 123 of 133 farms. When the top 10 serotypes were considered, there was no significant difference in the range of serotypes isolated by the two culturing methods. The overall S. enteritidis prevalence for California flocks was 10.5% (14/133). The overall row prevalence for S. enteritidis for all the farms was 1.1% (24/2128), and the overall pool prevalence was 2.4% (13/532). Sixty percent (12/20) of the S. enteritidis isolates from the positive farms were phage type 4, and 40% (8/20) represented five other phage types (1, 6B, 7, 8, and 28).