Nonenteric Lesions of Necrotic Enteritis in Commercial Chickens in California: 25 Cases (2009-2018).

Necrotic enteritis (NE) is an important enteric disease affecting a wide variety of avian species, including poultry, caused by Clostridium perfringens type G and, rarely, type C. Significant economic losses can result from elevated mortality rates and poor performance, such as decreased weight gain associated with intestinal damage and impaired absorption of nutrients. Additional losses can result from elevated condemnation at the processing plant because of a high incidence of cholangiohepatitis. Nonenteric lesions associated with NE have been rarely reported. This paper describes uncommon presentations of NE in commercial chickens received by the California Animal Health and Food Safety Laboratory (Turlock and Tulare branches) between 2009 and 2018. Overall, extraintestinal lesions associated with C. perfringens were diagnosed in 25 cases of NE involving commercial broiler chickens. The extraintestinal sites most commonly affected included liver, followed by gizzard, bursa of Fabricius, gall bladder, and spleen. The etiology of these lesions, C. perfringens, was confirmed from a combination of gross, bacteriologic, microscopic, and immunohistochemical findings. The most common predisposing factors for NE identified were coccidiosis (56%, 14/25) and immunosuppressive disease agents, including infectious bursal disease virus (16%, 4/25) and fowl adenovirus group 1 (4%, 1/25). Additionally, four cases (16%) had microscopic lesions compatible with cystic enteritis, probably of viral etiology. This study describes the incidence of extraintestinal lesions of NE in chickens, underlying the role of enteric disorders and immunosuppression as major predisposing factors for the development of NE.

Chlamydiosis in a Gouldian Finch (Erythrura gouldiae).

Avian chlamydiosis is an infection caused by obligate intracellular and Gram-negative bacteria belonging to the family Chlamydiaceae and has been reported in more than 450 avian species distributed in 30 orders. In particular, a high prevalence of infection has been demonstrated in wild passerine populations, including both asymptomatic and clinically ill individuals, suggesting a role of these avian species as important carriers. In May 2018, avian chlamydiosis was diagnosed in a 1-year-old male Gouldian finch (Erythrura gouldiae) at the Turlock Branch of the California Animal Health and Food Safety Laboratory System. The bird belonged to an outdoor aviary with mixed avian species, including Gouldian finches, doves (Geopelia cuneata and Spilopelia chinensis), and psittacines (Aratinga, Psittacula, Pyrrhura, and Trichoglossus sp.). Severe respiratory distress and mortality were noted among the finches. Gross and histopathologic lesions were concentrated in the liver and spleen, with a mild involvement of the upper respiratory tract. Chlamydia spp. were detected in the spleen and kidney by real-time PCR and were further confirmed by immunohistochemistry. Subsequently, Chlamydia psittaci was isolated from the liver and spleen and characterized as a CP3-like strain (genotype B). In addition, viral particles compatible with circovirus were identified in the liver by direct electron microscopy. To the authors' knowledge, this is the first report of avian chlamydiosis with hepatic viral particles consistent with circovirus infection in a Gouldian finch.

Reporte de caso- Clamidiosis en un pinzón diamante de Gould (Chloebia gouldiae). La clamidiosis aviar es una infección causada por bacterias intracelulares y Gramnegativas obligadas que pertenecen a la familia Chlamydiaceae y se ha reportado en más de 450 especies de aves distribuidas en 30 órdenes. En particular, se ha demostrado una alta prevalencia de infección en poblaciones de paseriformes silvestres, incluyendo individuos asintomáticos y clínicamente enfermos, lo que sugiere un papel de estas especies aviares como portadores importantes. En mayo del año 2018, se diagnosticó clamidiosis aviar en un pinzón diamante de Gould (Chloebia gouldiae) de un año de edad remitido a la sede en Turlock del Sistema de Laboratorios de Salud Animal y Seguridad Alimentaria del Estado de California. El ave pertenecía a un aviario al aire libre con especies mixtas de aves, incluyendo los diamantes de Gould, palomas (Geopelia cuneata y Spilopelia chinensis) y psitacinas (Aratinga, Psittacula, Pyrrhura y Trichoglossus sp.). Se observaron problemas respiratorios severos y mortalidad entre los pinzones. Las lesiones macroscópicas e histopatológicas se concentraron en el hígado y el bazo, con problemas leves en el tracto respiratorio superior. Se detectó Chlamydia spp. en el bazo por PCR en tiempo real y fueron confirmados por inmunohistoquímica. Posteriormente, se aisló Chlamydia psittaci del hígado y el bazo y se caracterizó como una cepa de tipo CP3 (genotipo B). Además, se identificaron partículas virales compatibles con circovirus en el hígado mediante microscopía electrónica directa. Según el conocimiento de los autores, este es el primer informe de clamidiosis aviar con partículas virales hepáticas compatibles con infección por circovirus en un pinzón diamante de Gould.

Mycotic pododermatitis and mycotic pneumonia in commercial turkey poults in northern California.

Seven 5-week-old broad-breasted white commercial meat turkeys were submitted to the California Animal Health and Food Safety laboratory in Turlock with a history of respiratory illness. The primary diagnostic findings were mycotic pododermatitis and mycotic pneumonia. The unique feature of this case was the colonization of footpad epidermis and subcutis by fungal hyphae in commercial turkey species. No fungal cultures were undertaken at the time of the necropsy; therefore, paraffin-embedded tissue sections of lung and footpads were used to extract, amplify, and sequence mycotic DNA. A mixed population of fungi was identified in both lung and footpads by polymerase chain reaction amplification of part of the large subunit ribosomal RNA gene using broad-range fungal primers and DNA sequencing. In footpads, sequences matching Cryptococcus saitoi and Cladosporium and Cudoniella species were identified. It is believed that these fungi were opportunistic pathogens originating from the litter. The fungi identified from lungs were Aspergillus species, most closely matching Aspergillus flavus and Arxiozyma telluris (most likely a contaminant). Mycotic pododermatitis in avian species is considered a rare pathologic finding, and few documented reports are available. The on-farm prevalence of footpad lesions was estimated at 3%, and there was no associated increase in the incidence of lameness or weight depression in affected birds. Microscopically, a granulomatous inflammatory reaction associated with fungal hyphae was observed in lung parenchyma. Disruption of keratinized epidermis, encrustations, and acute inflammation were also noted in footpads invaded with fungal hyphae.

The diagnosis of very virulent infectious bursal disease in California pullets.

This report documents the occurrence of a very virulent infectious bursal disease virus (vvIBDV) in Northern California commercial brown pullets. Diagnosis was made from multiple accessions from two neighboring and epidemiologically related ranches submitted to the California Animal Health and Food Safety (CAHFS) laboratory. Pullets, 11 and 14 wk of age from ranch A (rA) and ranch B (rB) respectively, were submitted from infectious bursal disease virus vaccinated flocks experiencing a drastic increase in mortality. The December 2008 outbreak resulted in 26% and 34% mortality on rA and rB respectively. Gross and histologic lesions characteristic of acute vvIBDV were observed. Gross lesions included edematous bursas, hemorrhages at the junction of the proventriculus and gizzard as well as hemorrhages on skeletal muscles. Microscopic lesions included severe lymphoid necrosis and inflammation in edematous bursas, lymphoid necrosis in thymus, spleen, Peyer's patches and cecal tonsils. Diagnosis of vvIBDV was confirmed by molecular characterization of the IBDV from bursas as well as viral pathogenicity in specific-pathogen-free birds. RT-PCR and nucleotide sequencing of the hypervariable region of the VP2 (vVP2) gene segment of the IBDV genome was performed on rA, rB and embryo passaged rA virions.The amino acids compatible with vvIBDV isolates: 222(Ala), 242(Ile), 256(Ile), 294(Ile) and 299(Ser) were reported from both ranches. In addition, nucleotide sequencing of a fragment of the VP1 gene demonstrated the viruses have the segment B genotype associated with highly pathogenic vvIBDV. Inocula of 10(5.5) 50% egg infective dose of vvIBDV virus from rA and rB were introduced orally into two groups (g1 and g2 respectively) of 4 wk 2-day-old SPF leghorns. At 4 days postinoculation, there was 100% (22/22) morbidity in g1 and g2; 91% (20/22) mortality in g1; 100% (22/22) mortality for g2; 0% (0/20) morbidity and 0% (0/ 20) mortality was reported in the control group. This is the first occurrence of vvIBDV reported from birds in the United States.

Fowl cholera and acute heart rupture in a backyard turkey.

Pasteurella multocida is the causative agent of fowl cholera, an economically important disease of commercial and backyard poultry. Turkeys are particularly susceptible to fowl cholera; both backyard and commercial turkeys can succumb to disease. On April 10, 2018, a dead 9-mo-old male Bronze turkey was submitted to the California Animal Health and Food Safety Laboratory System (CAHFS)-Turlock branch for postmortem examination. History included previous housing and fighting with another male turkey, after which separation by a fence was instituted. Fighting continued, and depression and anorexia of 2 d duration was followed by acute collapse and death. At autopsy, blood clots markedly expanded the pericardium, and a tear was visible in the left ventricular free wall. Vegetative aortic valvular lesions were observed. Microscopically, infarcts were observed in kidney, liver, heart, spleen, and pancreas, with large numbers of gram-negative bacterial colonies present in most organs. P. multocida was isolated from multiple organs, and identified as serotype 2,5 and fingerprint 1604. Septic embolization from the vegetative valvular aortic lesions likely led to infarcts in multiple organs, including the left ventricular free wall, which ultimately caused weakening of the ventricular wall, ventricular rupture, and exsanguination into the pericardial space. Rupture of the left ventricular free wall has not been previously documented in turkeys with P. multocida infection, to our knowledge, and demonstrates an atypical presentation of fowl cholera in this backyard turkey.

Partial Molecular Characterization and Pathogenicity Study of an Avian Reovirus Causing Tenosynovitis in Commercial Broilers.

This study describes the molecular characterization of avian reoviruses (ARVs) isolated during an outbreak in commercial chickens between 2015 and 2016. In addition, a pathogenicity study of a selected ARV strain isolated from a field case of viral tenosynovitis in commercial broiler chickens was performed. On the basis of phylogenetic analysis of a 1088-bp fragment of the ARV S1 gene, the investigated sequences were differentiated into five distinct genotypic clusters (GCs), namely GC1, GC2, GC3, GC4, and GC6. Specific-pathogen-free (SPF) and commercial broiler chickens were challenged with the GC1 genetic type MK247011, at 14 days of age via the interdigital toe web. No significant effects in body weight gain and feed conversion were detected in both chicken types. The Δ interdigital web thickness was most severe at 4 days postchallenge (DPC) in both the SPF and broiler subgroups. The inflammation in SPF birds was slightly more severe compared with broilers. Neither mortality nor clinical signs occurred in the infected groups for the duration of the experiment, despite the presence of significant microscopic lesions in challenged birds. Microscopic changes of tenosynovitis became evident at 3 DPC, with the highest incidence and severity detected at 14 and 21 DPC, respectively. Seroconversion against ARV occurred 3 wk postchallenge, and the microscopic lesions detected in tendon and heart sections were highly compatible with those described in the field. Increased severity of tenosynovitis and epicarditis lesions were noted in the ARV-challenged groups compared with the control groups. Although SPF and broiler chickens showed comparable responses to the challenge with an ARV genetic variant, detected lesions were subclinical, denoting the limitations of our challenge approach. The age selected in this experiment possibly influenced the course of the infection. Data from this study highlight the genotypic diversity of isolates in California, and the outcome of the pathogenicity study can be used as a basis to improve protocols for pathogenicity studies to characterize ARV variants causing clinical disease in the field.

Caracterización molecular parcial y estudio de patogenicidad de un reovirus aviar que causa tenosinovitis en pollos de engorde comerciales. Este estudio describe la caracterización molecular de reovirus aviares (ARV) aislados durante un brote en pollos comerciales entre los años 2015 y 2016. Además, se realizó un estudio de patogenicidad de una cepa de reovirus seleccionada que fue aislada de un caso de campo de tenosinovitis viral en pollos de engorde comerciales. Con base en el análisis filogenético de un fragmento de 1088 pb del gene S1 de reovirus, las secuencias investigadas se diferenciaron en cinco grupos genotípicos distintos (GCs), denominados, GC1, GC2, GC3, GC4 y GC6. Aves libres de patógenos específicos (SPF) y pollos de engorde comerciales se desafiaron con el tipo genético GC1 MK247011 a los 14 días de edad a través de la membrana interdigital. No se detectaron efectos significativos en el aumento de peso corporal ni en la conversión de alimento en ambos tipos de aves. El grosor de la banda interdigital diferencial fue más severa a los cuatro días posteriores al desafío en las aves libres de patógenos específicos y en los pollos de engorde. La inflamación en las aves libres de patógenos específicos fue ligeramente más severa en comparación con los pollos de engorde. No se presentó mortalidad ni signos clínicos en los grupos infectados durante la duración del experimento, a pesar de la presencia de lesiones microscópicas significativas en las aves desafiadas. Los cambios microscópicos de la tenosinovitis se hicieron evidentes a los tres días postinoculación, con la mayor incidencia y severidad detectadas a los 14 y 21días postinoculación, respectivamente. La seroconversión para reovirus ocurrió tres semanas después del desafío, y las lesiones microscópicas detectadas en secciones de tendón y corazón fueron altamente compatibles con las descritas en el campo. El aumento en la severidad de las lesiones de tenosinovitis y epicarditis se observó en los grupos expuestos a reovirus aviar en comparación con los grupos de control. Aunque las aves libres de patógenos específicos y los pollos de engorde mostraron respuestas comparables ante el desafío con una variante genética de reovirus, las lesiones detectadas fueron subclínicas, lo que denota las limitaciones de nuestro enfoque de desafío. La edad seleccionada en este experimento posiblemente influyó en el curso de la infección. Los datos de este estudio resaltan la diversidad genotípica de los aislamientos en California y el resultado del estudio de patogenicidad se puede usar como base para mejorar los protocolos de los estudios de patogenicidad para caracterizar las variantes de reovirus que causan enfermedades clínicas en el campo.

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.

Rotavirus A Associated with Clinical Disease and Hepatic Necrosis in California Pigeons (Columba livia domestica).

Retrospective analysis of pigeon necropsy submissions to the California Animal Health and Food Safety Laboratory System from 2000 to 2018 revealed 14 submissions diagnosed with rotavirus A hepatic necrosis or "reoviruslike" viral hepatitis. Nine of the 14 submissions (64%) occurred in 2018. Submissions were racing pigeons and squab breeders from flocks with increased mortality. Juvenile and adult pigeons were submitted with a history of depression, diarrhea, regurgitation, labored breathing, and weakness. Flock morbidity peaked at 80% and mortality at 28%. The most consistent findings on postmortem examination were variably congested, mottled, and enlarged livers and spleens. Microscopically, mild to severe hepatic necrosis was observed with variable bile duct hyperplasia, sinusoidal congestion, hemosiderosis, and portal lymphoplasmacytic inflammation. Rotavirus A was detected in hepatocytes and inflammatory cells by immunohistochemistry. Negative-stain electron microscopy identified viral particles consistent with a member of Reoviridae in all negatively stained liver homogenates. Eleven cases were analyzed by reverse transcriptase-PCR targeting rotavirus A viral protein (VP) 6 and VP7 genes. Subsequent phylogenetic analysis of the VP6 and VP7 sequences compared to published Chinese, Nigerian, and German rotavirus A VP6 and VP7 sequences demonstrated the formation of two and three distinct clades, respectively. To the authors' knowledge, rotavirus A hepatic necrosis in pigeons has not been previously reported in the United States and represents a significant emerging disease for the pigeon industry due to the potential for high flock mortality and lost production.

Rotavirus A asociado con enfermedad clínica y necrosis hepática en palomas de California (Columba livia domestica). El análisis retrospectivo de los casos de necropsias de palomas remitidos al Sistema de Laboratorio de Salud Animal y Seguridad Alimentaria del Estado de California entre los años 2000 a 2018 reveló 14 casos con diagnóstico de necrosis hepática por rotavirus A, o hepatitis viral ocasionada por "virus similares a reovirus". Nueve de los 14 casos (64%) ocurrieron en el año 2018. Los casos fueron de palomas de competencia y de criadores de pichones de parvadas con aumento en la mortalidad. Se presentaron palomas jóvenes y adultas con antecedentes de depresión, diarrea, regurgitación, dificultad para respirar y debilidad. La morbilidad mayor fue de un 80% como máximo y la mortalidad fue de un 28%. Los hallazgos más consistentes en el examen post mortem incluyeron hígados y bazos con congestión, apariencia moteada y aumento de tamaño de forma variable. Microscópicamente, se observó necrosis hepática de leve a severa con hiperplasia variable de los conductos biliares, congestión de sinusoides, hemosiderosis e inflamación linfoplasmocítica portal. Se detectó rotavirus A en hepatocitos y células inflamatorias por inmunohistoquímica. La microscopía electrónica de tinción negativa identificó partículas virales consistentes con virus posiblemente miembros de la familia Reoviridae en todos los homogenizados de hígado teñidos negativamente. Se analizaron once casos mediante transcripción reversa y PCR dirigida a los genes de la proteína viral (VP) 6 y VP7 del rotavirus A. El análisis filogenético posterior de las secuencias de los genes VP6 y VP7 cuando se compararon con secuencias de genes VP6 y VP7 de rotavirus A de China, Nigeria y de Alemania previamente publicadas demostró la formación de dos y tres clados distintos, respectivamente. De acuerdo con el conocimiento de los autores, la necrosis hepática por rotavirus A en palomas no se había reportado previamente en los Estados Unidos y representa una enfermedad emergente importante para la industria de las palomas debido a su potencial de alta mortalidad de la parvada y a las pérdidas en la producción.

Bilateral malacia associated with sodium poisoning in turkey poults.

Improper cleaning of the water storage tank resulted in a toxic concentration of sodium in drinking water in a commercial turkey flock. Within the first week after placement 40% of the birds in the flock died. Clinically, poults were depressed and weak, huddled together, and reluctant to walk. At necropsy the birds had crops and gizzards filled with rice hulls, moderately swollen livers, distended gall bladders, and congested lungs. Neither ascites nor round heart was observed. The major microscopic lesion was multifocal symmetrical malacia of brain and spinal cord. Laboratory results revealed a high concentration of sodium in water (2340 mg/liter). The concentration of sodium in brain and liver ranged from 1870 to 2680 (mean = 2185; SD = 321.5) mg/liter wet weight and from 1810 to 2360 (mean = 2191.67; SD = 193.2) mg/liter wet weight, respectively, whereas the normal expected sodium concentration in the brain and liver tissues from young turkeys (< 7 days old) that were submitted for other causes averaged 1233 and 983 mg/liter wet weight, respectively. Based on the histological and toxicological results, a diagnosis of salt poisoning was made. This case investigation demonstrated that sodium analysis of brain and liver are diagnostically useful when confirming sodium poisoning in young turkeys.

Liposarcoma in a Backyard Silkie and Retrospective Summary of Neoplasms Diagnosed in Backyard Chickens Submitted to the California Animal Health and Food Safety Laboratory System, 2008-2017.

Liposarcomas are a malignant neoplasm of adipocytes, and are rarely diagnosed in avian species. This case report describes the evidence supporting a diagnosis of metastatic liposarcoma in a backyard silkie chicken. On September 28, 2017, a dead 3-yr-old backyard silkie chicken, with a history of unknown skin lesions involving the entire body and severe weight loss, was submitted to California Animal Health and Food Safety Laboratory System-Turlock branch for necropsy. At necropsy, raised necrotic lesions involving the majority of the skin and multiple nodules in the liver, spleen, and bone marrow were noticed. Microscopically, stellate, spindle, and myxoid cells containing large vacuoles, which were confirmed as lipid droplets by Oil Red O, were observed infiltrating the dermis and underlying a necrotic epidermis, with metastasis to liver, spleen, bone marrow, and ovary being the most significant findings. PAS, Oil Red O, Ziehl-Neelsen, Congo red, Gram, and Von Kossa stains, along with immunohistochemistry for pan cytokeratin, vimentin, S100, CD3, pp38, and Meq were used to classify the lesions. Intensely positive vimentin immunohistochemistry, along with large quantities of Oil Red O-positive lipid droplets within the neoplastic cells, were supportive of our diagnosis of liposarcoma. The incidence of neoplastic diseases diagnosed in backyard flock submissions to CAHFS system wide from 2008 to 2017 was also reviewed.

Streptococcosis in Commercial and Noncommercial Avian Species in California: 95 Cases (2000-2017).

Streptococcal bacterial species represent common inhabitants of the intestinal tract of animals and humans with a potential for opportunistic infections. Streptococcosis has been identified in turkey poults ( Meleagris gallopavo), ducklings and goslings (Anatidae), broiler chickens, semimature-adult chickens ( Gallus gallus domesticus), and young and adult pigeons (Columbidae). However, the exact underlying factors that lead to bacterial invasion of the blood stream and tissue colonization have not been completely elucidated. The electronic database of the California Animal Health and Food Safety laboratory (Fresno, Tulare, and Turlock branches) was searched for necropsy cases in which streptococcosis was diagnosed in different avian species between January 2000 and August 2017. A total of 95 cases, involving both commercial operations and noncommercial premises, were analyzed. Streptococcus spp., Streptococcus bovis, and Streptococcus gallolyticus were identified from multiple organs, with macroscopic or histopathologic lesions (or both) indicative of septicemia in 23 (24%), 40 (42%), and 30 (32%) cases, respectively. Streptococcus pluranimalium and Streptococcus lutetiensis were also isolated from one (1%) and two (2%) cases, respectively. Turkey poults, broiler chickens, and ducklings were the most-commonly affected species with streptococcosis. Splenitis and hepatitis were the most-common lesions observed and these were the organs with the highest isolation rate. An overview of the clinical and pathologic presentation, and possible predisposing conditions associated with this bacterial infection, is provided.

Otitis and meningoencephalitis associated with infectious coryza ( Avibacterium paragallinarum) in commercial broiler chickens.

Infectious coryza, caused by Avibacterium paragallinarum, is an acute respiratory disease of poultry that can result in substantial morbidity, mortality, and economic losses. In March 2017, the Turlock branch of the California Animal Health and Food Safety laboratory system encountered an unusual clinical and pathologic presentation of infectious coryza in 6 live, 29-d-old, commercial broiler chickens that were submitted for diagnostic investigation. Antemortem evaluation revealed severe neurologic signs, including disorientation, torticollis, and opisthotonos. Swollen head-like syndrome and sinusitis were also present. Histologically, severe sinusitis, cranial osteomyelitis, otitis media and interna, and meningoencephalitis were noted, explaining the clinical signs described. A. paragallinarum was readily isolated from the upper and lower respiratory tract, brain, and cranial bones. Infectious bronchitis virus (IBV) was also detected by PCR, and IBV was isolated in embryonated chicken eggs. Based on sequencing analysis, the IBV appeared 99% homologous to strain CA1737. A synergistic effect between A. paragallinarum and IBV, resulting in exacerbation of clinical signs and increased mortality, may have occurred in this case. A. paragallinarum should be considered among the possible causes of neurologic signs in chickens. Appropriate media should be used for bacterial isolation, and the role of additional contributing factors and/or complicating agents should be investigated in cases of infectious coryza.

Vegetative Valvular Endocarditis and Hepatitis Associated with Helcococcus ovis in a 7-year-old White Leghorn Rooster.

Helcococcus ovis is a slow-growing, pyridoxal-dependent, Gram-positive coccus belonging to the Peptostreptococcaceae family. Bacteria belonging to the genus Helcococcus are considered normal inhabitants of keratinized epithelium in humans; however, several reports support their role as pathogens in humans and several animal species. This case report describes the identification of H. ovis in a white leghorn rooster with valvular vegetative endocarditis and hepatitis. In February 2017 one dead, 7-yr-old, white leghorn rooster was submitted to the California Animal Health and Food Safety Turlock laboratory for diagnostic testing. Postmortem and microscopic examination revealed vegetative endocarditis and aortic thrombosis associated with large numbers of Gram-positive cocci. Myocarditis and extensive necrotic hepatitis were also noticed. Helcococcus ovis was isolated in large numbers from the aortic endothelium and confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Bacterial colonies become evident 48 hr postincubation and exhibited a satellite growth around Escherichia coli on blood agar plates. A similar relationship has been described between Helcococcus spp. and Staphylococcus aureus. The primary site of infection in this chicken was not determined. To our understanding this is the first report of H. ovis infection in an avian species. The fastidious nature and nutritional requirements of Helcococcus spp. must be considered in order to allow proper identification and avoid misdiagnosis. Further studies are needed to define pathogenesis, virulence factors, and predisposing conditions associated with this microorganism.

Avian Encephalomyelitis in Layer Pullets Associated with Vaccination.

Avian encephalomyelitis (AE) was diagnosed in three flocks of leghorn layer pullets following AE vaccination. Ages of the birds were 11, 12, and 14 wk. The submissions came from three different companies located in two geographic areas of the Central Valley of California. The clinical signs included birds down on their legs, unilateral recumbency or sitting on their hocks, lethargy, reluctance to move, dehydration, unevenness in size, low weight, tremors of the head in a few birds, and mildly to moderately elevated mortality. The flocks had been vaccinated against fowl pox and AE with a combined product in the wing-web 2 wk prior to the onset of AE clinical signs. Histopathologic examination revealed lesions consistent with AE, including lymphocytic perivascular infiltration and neuronal central chromatolysis in the brain and spinal cord, as well as gliosis in the cerebellar molecular layer. The AE virus was detected by reverse-transcriptase PCR in the brain homogenate from three cases and peripheral nerves in one case. Additionally, the AE virus was isolated in specific-pathogen-free (SPF) embryonated eggs from brain tissue pool samples. Other avian viral infections capable of causing encephalitis, including avian paramyxoviruses, avian influenza virus (AIV), West Nile virus (WNV), eastern equine encephalitis virus (EEEV), and western equine encephalitis virus (WEEV), were ruled out by attempting virus isolation and molecular procedures.

Yersinia pseudotuberculosis in Eurasian Collared Doves (Streptopelia decaocto) and Retrospective Study of Avian Yersiniosis at the California Animal Health and Food Safety Laboratory System (1990-2015).

In February 2015, two Eurasian collared doves (Streptopelia decaocto) were submitted dead to the California Animal Health and Food Safety (CAHFS) Laboratory, Turlock branch, from a private aviary experiencing sudden, high mortality (4/9) in adult doves. In both doves, the gross and histologic lesions were indicative of acute, fatal septicemia. Grossly, there were numerous pale yellow foci, 1 to 2 mm in diameter, in the liver and spleen. Microscopically, these foci were composed of acute severe multifocal coagulative necrosis of hepatocytes and splenic pulp with infiltration of heterophils mixed with fibrin and dense colonies of gram-negative bacteria. Yersinia pseudotuberculosis was isolated from the lung, liver, spleen, heart, ovary, kidney, and trachea. The organism was susceptible to most antibiotics it was tested against, except erythromycin. Based on a retrospective study of necropsy submissions to CAHFS between 1990 and 2015, there were 77 avian case submissions of Y. pseudotuberculosis. There were 75/77 cases identified from a wide range of captive avian species from both zoo and private facilities and 2/77 cases from two backyard turkeys submitted from one premise. The largest number of cases originated from psittacine species (31/77). The lesions most commonly described were hepatitis (63/77), splenitis (49/77), pneumonia (30/77), nephritis (16/77), and enteritis (12/77). From 1990 to 2015, there was an average of three cases of avian pseudotuberculosis per year at CAHFS. Although there were no cases diagnosed in 1993 and 1994, in all other years, there were between one and eight cases of Y. pseudotuberculosis detected from avian diagnostic submissions.

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.

Acute depigmentation of fertile brown eggs in a commercial layer operation.

Rapid depigmentation of brown eggs is an infrequent but startling event in the commercial egg industry that can result in significant economic losses. Loss of shell pigment in brown-shelled eggs is caused by various factors. In many cases, the exact cause of flock-wide pigment loss remains undetermined. A rapid decline in shell pigmentation was observed in 2 flocks of Hyline brown layers. The lack of evidence of an infectious disease process suggested a feed or management problem. On the basis of a small-scale, "in-house" feeding trial, the feed was identified as the cause of depigmentation. Feed analysis by liquid chromatography with mass spectrometry confirmed the presence of 4,4'-dinitrocarbanilide, a major component of nicarbazin (NCZ). There was no evidence of increased mortality, and only a slight but transient drop in the egg production was observed. Depigmentation effects were rapidly reversed after replacing the feed with NCZ-free feed.

Host inflammatory response governs fitness in an avian ectoparasite, the northern fowl mite (Ornithonyssus sylviarum).

Vertebrate immune responses to ectoparasites influence pathogen transmission and host fitness costs. Few studies have characterized natural immune responses to ectoparasites and resultant fitness effects on the ectoparasite. These are critical gaps in understanding vertebrate-ectoparasite interaction, disease ecology and host-parasite co-adaptation. This study focused on an ectoparasite of birds--the northern fowl mite (NFM) (Ornithonyssus sylviarum). Based on prior evidence that chickens develop resistance to NFM, these experiments tested two hypotheses: (i) skin inflammation blocks mite access to blood,impairing development, reproduction and survival; and (ii) host immunogenetic variation influences the inflammatory response and subsequent effects on the ectoparasite. On infested hosts, histology of skin inflammation revealed increased epidermal cell number and size, immigration of leukocytes and deposition of serous exudates on the skin surface. Survival of adult mites and their offspring decreased as the area of skin inflammation increased during an infestation. Inflammation increased the distance to blood vessels beyond the length of mite mouthparts (100-160 lm) and prevented protonymphs and adults from reaching a blood source. Consequently, protonymphs could not complete development, evidenced by a significant inverse relationship between inflammation and protonymph feeding success, as well as an increasing protonymph/adult ratio. Adult females were unable to feed and reproduce, indicated by an inverse relationship between inflammation and egg production, and decreasing female/juvenile ratio. These combined impacts of host inflammation reversed NFM population growth. Intensity of inflammation was influenced by the genotype of the major histocompatibility complex(MHC), supporting previous research that linked these immunological loci with NFM resistance. Overall, these data provide a model for a mechanism of avian resistance to an ectoparasitic arthropod and the fitness costs to the parasite of that host defense.