Eva Wallner-Pendleton

Inhibition of Salmonella typhimurium on Agar Medium and Poultry Skin by Ultraviolet Energy

Ultraviolet radiation (UV) was effective in destroying Salmonella typhimurium on agar plates and poultry skin. Agar plates inoculated with varying numbers of colony-forming units (CFU) of S. typhimurium (1.2 x 10(2) to 1.7 x 10(9) were subjected to different doses of UV light to determine optimal killing. Poultry skin was also inoculated with varying CFU of S. typhimurium per 2 cm2 of skin and subjected to UV light. UV light treatment of inoculated agar plates revealed almost complete elimination (99.9%) of S. typhimurium at 2,000 microW x s x cm(-2). Bacterial reduction was less effective on the surface of poultry skin when a 80.5% reduction in S. typhimurium was obtained at 2,000 microW x s x cm(-2).

Investigation of H7N2 Avian Influenza Outbreaks in Two Broiler Breeder Flocks in Pennsylvania, 2001-02

Abstract An avian influenza (AI ) outbreak occurred in meat-type chickens in central Pennsylvania from December 2001 to January 2002. Two broiler breeder flocks were initially infected almost simultaneously in early December. Avian influenza virus (AIV), H7N2 subtype, was isolated from the two premises in our laboratory. The H7N2 isolates were characterized as a low pathogenic strain at the National Veterinary Services Laboratories based on molecular sequencing of the virus hemagglutinin cleavage site and virus challenge studies in specific-pathogen-free leghorn chickens. However, clinical observations and pathologic findings indicated that this H7N2 virus appeared to be significantly pathogenic in meat-type chickens under field conditions. Follow-up investigation indicated that this H7N2 virus spread rapidly within each flock. Within 7 days of the recognized start of the outbreak, over 90% seroconversion was observed in the birds by the hemagglutination inhibition test. A diagnosis of AI was made within 24 hr of bird submission during this outbreak using a combination of virus detection by a same-day dot–enzyme-linked immunosorbent assay and virus isolation in embryonating chicken eggs. Follow-up investigation revealed that heavy virus shedding (90%–100% of birds shedding AIV) occurred between 4 and 7 days after disease onset, and a few birds (15%) continued to shed virus at 13 days post–disease onset, as detected by virus isolation on tracheal and cloacal swabs. AIV was not detected in or on eggs laid by the breeders during the testing phase of the outbreak. The two flocks were depopulated at 14 days after disease onset, and AIV was not detected on the two premises 23 days after depopulation.

Risk Factors Associated With Salmonella in Laying Hen Farms: Systematic Review of Observational Studies

SUMMARY Salmonella contamination of laying hen flocks and shell eggs is associated with various management and environmental factors. Foodborne outbreaks of human salmonellosis have been traced back to consumption of Salmonella-contaminated shell eggs. In the present study, a systematic literature review was conducted to identify and provide an evidence-based overview of potential risk factors of Salmonella contamination of laying hens, layer premises, and shell eggs. This systematic literature search was conducted using AGRICOLA, CAB Abstracts, and PubMed databases. Observational studies that identified risk factors for Salmonella contamination of layer flocks and shell eggs were selected, and best evidence was synthesized to summarize the results. Altogether, 13 cross-sectional studies and four longitudinal studies published in English were included in the review. Evidence scores were assigned based on the study design and quality of the study to grade the evidence level. The strength of association of a risk factor was determined according to the odds ratios. In this systematic review, the presence of previous Salmonella infection, absence of cleaning and disinfection, presence of rodents, induced molting, larger flock size (>30,000 hens), multiage management, cage housing systems, in-line egg processing, rearing pullets on the floor, pests with access to feed prior to movement to the feed trough, visitors allowed in the layer houses, and trucks near farms and air inlets were identified as the risk factors associated with Salmonella contamination of laying hen premises, whereas high level of manure contamination, middle and late phase of production, high degree of egg-handling equipment contamination, flock size of >30,000, and egg production rate of >96% were identified as the risk factors associated with Salmonella contamination of shell eggs. These risk factors demonstrated strong to moderate evidence of association with Salmonella contamination of laying hens and shell eggs. Eggshells testing positive for Salmonella were 59 times higher when fecal samples were positive and nine times higher when floor dust samples were positive. Risk factors associated with Salmonella Enteritidis infection in laying hens were flock size, housing system, and farms with hens of different ages. As a summary, this systematic review demonstrated that Salmonella contamination of laying hen flocks and shell eggs in layer production systems is multifactorial. This study provides a knowledge base for the implementation of targeted intervention strategies to control Salmonella contamination of laying hen flocks and shell eggs.

Summary of the 2001–02 Pennsylvania H7N2 Low Pathogenicity Avian Influenza Outbreak in Meat Type Chickens

Abstract H7N2 low-pathogenicity (LP) avian influenza (AI) virus was isolated from chickens submitted to the Pennsylvania Animal Diagnostic Laboratory System on December 4 and 5, 2001. The cases were from two broiler breeder flocks in central Pennsylvania that had clinical signs of an acute, rapidly spreading respiratory disease. Seroconversion to AI virus was detected on follow-up sampling. Subsequently, H7N2 LPAI virus was isolated in five different broiler flock cases submitted between December 14, 2001, and January 3, 2002. Clinical signs and lesions in broilers, when present, were compatible with multicausal respiratory disease. With the exception of one broiler flock that was processed, birds from all of the virus positive flocks were euthanatized in-house within 11 days of the original case submission date. Increased surveillance of poultry flocks within 10-mile radius zones centered at the foci of the positive farms continued until March 1, 2002. No additional cases were detected.

Diabetes mellitus in a red‐tailed hawk (Buteo jamaicensis)

An adult, free-living female red-tailed hawk (Buteo jamaicensis) with clinical signs of generalized weakness, polyuria, and polydipsia, was killed and necropsied. An ante mortem serum sample taken from the bird contained 54.3 mmole/1 glucose, and large amounts of glucose were found in the urine. At necropsy, the pancreas was small, pale pink with multiple, round, approximately 0.5 mm white foci. Light and electron microscopic examination of the pancreas revealed markedly vacuolated islet cells. Histochemical examination of the tissue showed that the vacuolated cells were beta-cells. This is the first report of spontaneously occurring diabetes mellitus in a raptor.

Several outbreaks of Yersinia pseudotuberculosis in California turkey flocks.

Yersinia pseudotuberculosis has been isolated from a wide range of animal species, both wild and domestic, but few references to turkeys can be found in literature. The first report of the disease in turkeys in the United States came from Rosenwald and Dickinson (9), who isolated the organism from 10 turkey flocks in Oregon in 1940-1941. In 1946, Blaxland (3) described outbreaks on eight turkey ranches in England, and in 1954, Mathey and Siddle (8) isolated the organism from a turkey in California. Kilian et al. (7) reported an isolation from a turkey hen in Oregon in 1954. In 1972, Wise and Uppal (11) described an outbreak of Y. pseudotuberculosis-induced osteomyelitis in turkey farms in England. The present report describes outbreaks of Y. pseudotuberculosis-induced septicemia and osteomyelitis in California turkey ranches.

Isolation and molecular characterization of newly emerging avian reovirus variants and novel strains in Pennsylvania, USA, 2011-2014.

Avian reovirus (ARV) infections of broiler and turkey flocks have caused significant clinical disease and economic losses in Pennsylvania (PA) since 2011. Most of the ARV-infected birds suffered from severe arthritis, tenosynovitis, pericarditis and depressed growth or runting-stunting syndrome (RSS). A high morbidity (up to 20% to 40%) was observed in ARV-affected flocks, and the flock mortality was occasionally as high as 10%. ARV infections in turkeys were diagnosed for the first time in PA in 2011. From 2011 to 2014, a total of 301 ARV isolations were made from affected PA poultry. The molecular characterization of the Sigma C gene of 114 field isolates, representing most ARV outbreaks, revealed that only 21.93% of the 114 sequenced ARV isolates were in the same genotyping cluster (cluster 1) as the ARV vaccine strains (S1133, 1733, and 2048), whereas 78.07% of the sequenced isolates were in genotyping clusters 2, 3, 4, 5, and 6 (which were distinct from the vaccine strains) and represented newly emerging ARV variants. In particular, genotyping cluster 6 was a new ARV genotype that was identified for the first time in 10 novel PA ARV variants of field isolates.

Acute septicemia caused by Streptococcus gallolyticus subsp. pasteurianus in turkey poults.

SUMMARY Streptococcus gallolyticus, previously known as Streptococcus bovis biotypes I and II/2, is a well-known cause of sepsis and meningitis in humans and birds. The present case report describes an outbreak of fatal septicemia associated with S. gallolyticus subsp. pasteurianus (S. bovis biotype II/2) in 11 turkey flocks in Pennsylvania between 2010 and 2013. Affected poults were 2–3 wk of age. Major clinical observation was sudden increase in mortality among turkey poults without any premonitory clinical signs. Postmortem examination findings revealed acute septicemia with lesions such as fibrinous pericarditis, meningitis, splenic multifocal fibrinoid necrosis, hepatitis, osteochondritis, myositis, and airsacculitis. Gram-positive cocci were isolated from several organs by routine bacterial culture. Biotyping identified bacteria as streptococci, whereas 16S ribosomal RNA gene sequencing identified them as S. gallolyticus subsp. pasteurianus. Antibiotic susceptibility profiles revealed that all the strains isolated were sensitive to penicillin and erythromycin with different sensitivity profiles for other antibacterial agents tested. The present study reports the first confirmed case of acute septicemia in turkey poults caused by S. gallolyticus subsp. pasteurianus. RESUMEN Reporte de Caso—Septicemia aguda causada por Streptococcus gallolyticus subsp. pasteurianus en pavipollos. Streptococcus gallolyticus, anteriormente conocido como Streptococcus bovis biotipos I y II/2, es una causa muy conocida de sepsis y meningitis en los seres humanos y aves. El presente reporte de caso describe un brote de septicemia fatal asociada con S. gallolyticus subsp. pasteurianus (S. bovis biotipo II/2) en 11 lotes de pavos en Pennsylvania entre los años 2010 y 2013. Los pavos afectados tenían entre 2 a 3 semanas de edad. La principal observación clínica fue el repentino incremento en la mortalidad entre los pavos jóvenes sin signos clínicos sugestivos. Los hallazgos durante el examen postmortem revelaron septicemia aguda con lesiones tales como pericarditis fibrinosa, meningitis, necrosis esplénica fibrinoide multifocal, hepatitis, osteocondritis, miositis y aerosaculitis. Se aislaron cocos gram positivos de varios órganos mediante el cultivo bacteriano de rutina. La biotipificación identificó a las bacterias como estreptococos, mientras que la secuenciación del gene de ARN ribosomal 16S las identificó como S. gallolyticus subsp. pasteurianus. Los perfiles de susceptibilidad a los antibióticos revelaron que todas las cepas aisladas eran sensibles a la penicilina y a la eritromicina con diferentes perfiles de sensibilidad para otros agentes antibacterianos ensayados. El presente estudio reporta el primer caso confirmado de septicemia aguda en pavipollos causado por S. gallolyticus subsp. pasteurianus.

Toxicity of Excess Dicalcium Phosphate in the Diet of Turkey Poults

High mortality in 1-week-old commercial turkey poults was attributed to the accidental substitution of dicalcium phosphate in the diet for corn. At necropsy of the affected birds, lesions were observed in the upper gastrointestinal tract, suggesting acute ingestion of a caustic substance. Mortality and gross and microscopic lesions were reproduced experimentally in turkey poults fed diets similar to the diet fed in the field case. The cause of these lesions was attributed to increased pH due to the phosphoric acid content of the diet.

A Retrospective Study of Salmonella Enteritidis Isolated from Commercial Layer Flocks

SUMMARY Consumption of shell eggs has been associated with Salmonella Enteritidis (SE) infections in humans in the United States. Because of this, the Pennsylvania Egg Quality Assurance Program (PEQAP) was developed and implemented in 1994. The PEQAP involves periodic flock testing and management practices to minimize SE contamination of shell eggs. Subsequently, the U.S. Food and Drug Administration (FDA) introduced a mandatory federal program in 2010 and 2012 for shell egg producers modeled closely after PEQAP to reduce the incidence and prevalence of SE during production, storage, and transport nationwide. In this study, a retrospective epidemiologic analysis was conducted by characterizing SE isolated from commercial layer environment samples and shell eggs submitted to the Animal Diagnostic Laboratory at The Pennsylvania State University using phage typing and pulsed-field gel electrophoresis (PFGE). The objective of this study was to determine the relatedness of SE isolates from hen house environments and shell eggs and to optimize the existing protocols of egg quality assurance programs by identifying the best layer-house environmental sampling time points in order to minimize SE contamination of shell eggs. A total of 94 SE isolates from 65 hen flocks on 35 premises in Pennsylvania recovered during 2007 to 2015 were used in this study. The SE phage type 8 and PFGE fingerprint type JEGX01.0004 most commonly associated with human SE infection was also the predominant type present in layer-house environments and shell eggs. This reconfirms hen house environmental monitoring is an effective method to identify SE-infected flocks. Further, the PEQAP program allowed SE detection of infected flocks earlier than the FDA program as it included an additional environmental test at 29–31 wk of age, enabling the earlier prevention of SE-contaminated shell eggs going to the market. Therefore, it is recommended to refine the sampling time points of the current FDA Egg Rule by adding hen house environmental testing at 29–31 wk of age.