Diagnosis and Control of a LPAI H5N8 Outbreak in a Japanese Quail (Coturnix coturnix japonica) Commercial Flock in the Central Valley of California.

In April 2014 an outbreak of low pathogenic avian influenza H5N8 North American genetic lineage was diagnosed in a commercial quail operation in Stanislaus County, California. Sudden increase in mortality prompted the submission of 20 Japanese quail hens (Coturnix c. japonica) to the California Animal Health and Food Safety Laboratory, Turlock Branch. Oropharyngeal and cloacal swabs tested positive for influenza A virus H5N8 by real-time reverse transcription-polymerase chain reaction. The virus was subsequently isolated. In vivo assay and sequencing of the hemagglutinin protein cleavage site classified the virus as a North American genetic lineage of low pathogenicity for chickens. Following the diagnosis, a rapid and coordinated response took place to contain the outbreak. The affected premise was depopulated, cleaned, and disinfected. Three areas from the affected premises-a 3 kilometer (km) radius (High Risk Zone), a 3-10 km area (Buffer Zone), and a 10-20 km (Surveillance Zone)-were established for avian influenza testing of commercial and noncommercial poultry operations. Surveillance testing and rapid control measures were successful in the control and eradication of the outbreak and revealed no area of spread of the virus from the index flock. This report describes the history, diagnosis, surveillance, and control measures applied to manage this outbreak.

Highly Pathogenic Eurasian H5N8 Avian Influenza Outbreaks in Two Commercial Poultry Flocks in California.

In January 2015, a highly pathogenic Eurasian lineage H5N8 avian influenza (AI) virus (AIV) was detected in a commercial meat turkey flock in Stanislaus County, CA. Approximately 3 wk later, a similar case was diagnosed in commercial brown layers from a different company located in Kings County, CA. Five 14-wk-old turkey hens were submitted to the California Animal Health and Food Safety Laboratory System (CAHFS), Turlock, and eleven 12-wk-old chickens were submitted to CAHFS, Tulare laboratory due to an acute increase in flock mortality. Gross lesions included enlarged and mottled pale spleens and pancreas in turkeys and chickens. Histologically, the major lesions observed in turkeys and chickens were splenitis, pancreatitis, encephalitis, and pneumonia. In both cases, diagnosis was based on real-time reverse transcriptase PCR (RRT-PCR), sequencing, and virus isolation from oropharyngeal and cloacal swabs. Confirmatory diagnosis and AIV characterization was done at the National Veterinary Services Laboratory, Ames, IA. The sequence of the AIV from both cases was 99% identical to an H5N8 AI virus (A/gyrfalcon/Washington/41088-6/2014) isolated from a captive gyrfalcon (Falco rusticolus) from Washington State in December 2014. Immunohistochemistry (IHC) performed on various tissues from both cases indicated a widespread AIV tissue distribution. Except for minor variations, the tissue distribution of the AI antigen was similar in the chickens and turkeys. There was positive IHC staining in the brain, spleen, pancreas, larynx, trachea, and lungs in both chickens and turkeys. Hearts, ovaries, and air sacs from the turkeys were also positive for the AI antigen. The liver sections from the chickens had occasional AI-positive staining in mononuclear cells, but the IHC on liver sections from the turkeys were negative. The bursa of Fabricius, small intestine, kidney, and skeletal muscle sections were negative for the AI antigen in both chickens and turkeys.

Longitudinal monitoring of two commercial layer flocks and their environments for Salmonella enterica serovar enteritidis and other Salmonellae.

Between August 20, 2001, and September 17, 2002, 1429 samples including drag swabs, egg belt or egg rollout swabs, fan-blade swabs, rodent organ and intestinal pools, beetle (Alphitobius diaperinus) pools, housefly (Musca domestica) pools, chicken organ and intestinal pools, and egg pools were obtained for Salmonella culture from two flocks from two different commercial layer ranches. The two ranches were purposefully selected for the study based on their previous status of Salmonella Enteritidis isolation using environmental drag swabs in cooperation with practicing veterinarians. Salmonella sp. was isolated from 337 out of 979 (34.42%) non-egg samples. No Salmonella was isolated from 450 egg pools collected from either ranch. S. enteritidis was isolated from samples obtained from ranch 1 from manure drag swabs, 4/284 (1.4%); rodent organs, 1/24 (4.2%); and housefly pool cultures 1/21 (4.8%). Salmonella Enteritidis was isolated from ranch 2 from mouse organ and intestinal pool samples, 1/24 (4.2%). Salmonella group B was isolated from all sample types except the insects. There was a statistically significant difference in isolation rates among seven serogroups of Salmonella: groups B, C1, C2, D, E, K, and untypeable (Pearson chi-square 18.96, P = 0.002). Overall, statistically significant differences were observed with respect to Salmonella isolation among the types of samples taken (Pearson chi-square 118.54, P < 0.0001). Intensive monitoring for Salmonella Enteritidis can be used to optimize a Salmonella reduction program for an individual poultry biosecurity unit.

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).

Whole genome sequencing and phylogenetic analysis of Bluetongue virus serotype 2 strains isolated in the Americas including a novel strain from the western United States.

Bluetongue is a potentially fatal arboviral disease of domestic and wild ruminants that is characterized by widespread edema and tissue necrosis. Bluetongue virus (BTV) serotypes 10, 11, 13, and 17 occur throughout much of the United States, whereas serotype 2 (BTV-2) was previously only detected in the southeastern United States. Since 1998, 10 other BTV serotypes have also been isolated from ruminants in the southeastern United States. In 2010, BTV-2 was identified in California for the first time, and preliminary sequence analysis indicated that the virus isolate was closely related to BTV strains circulating in the southeastern United States. In the current study, the whole genome sequence of the California strain of BTV-2 was compared with those of other BTV-2 strains in the Americas. The results of the analysis suggest co-circulation of genetically distinct viruses in the southeastern United States, and further suggest that the 2010 western isolate is closely related to southeastern strains of BTV. Although it remains uncertain as to how this novel virus was translocated to California, the findings of the current study underscore the need for ongoing surveillance of this economically important livestock disease.