Biomedical subjects

H J Barnes

Publications and source records attributed to H J Barnes.

88 records · Page 5Linked to original sources

PubMedDate not supplied

Prevalence of Alcaligenes faecalis in North Carolina broiler flocks and its relationship to respiratory disease.

In order to assess the role of Alcaligenes faecalis in respiratory disease of broilers, a study was conducted to determine the prevalence of this bacterium in North Carolina broilers and to determine the relationship of A. faecalis infection to clinical disease. Our studies showed that A. faecalis is prevalent in North Carolina commercial broilers during the winter months. Bacteriological examination of turbinates and tracheas revealed that almost 40% of individual birds between 35 and 45 days of age yielded positive cultures; 62% of tested flocks were infected. When present, A. faecalis was usually the predominant bacterium isolated. Furthermore, because of a higher frequency of A. faecalis isolation in broiler flocks with respiratory disease (75% vs. 29% in flocks without respiratory diseases), these studies suggest a causal relationship between this bacterium and clinical respiratory disease.

Alcaligenes↗

PubMedDate not supplied

Susceptibility of turkey poults from vaccinated and unvaccinated hens to alcaligenes rhinotracheitis (turkey coryza).

One specific-pathogen-free breeder flock of Beltsville small white turkeys was given two doses of oil-emulsion-adjuvanted Alcaligenes faecalis bacterin 3 months apart, and another flock was left unvaccinated. Progeny from each flock from eggs laid after both first and second vaccination were exposed to the homologous strain (838) of A. faecalis at 1 day of age either experimentally (10(7) colony-forming units intranasally) or naturally (continuous contact with an infected poult) and monitored for 2, 4, or 6 weeks. Progeny from vaccinated hens had substantial resistance to alcaligenes rhinotracheitis compared with progeny from unvaccinated hens; resistance was greatest in progeny from twice-vaccinated hens. Poults from vaccinated hens had improved livability and growth, delayed onset of infection and clinical signs, and a less severe disease process. The results of this study indicate that breeder hen vaccination could be a useful method for providing poults with early protection against alcaligenes rhinotracheitis.

Alcaligenes↗

PubMedDate not supplied

Experimental transmission of eastern equine encephalitis virus and Highlands J virus via semen of infected tom turkeys.

Tom turkeys were experimentally inoculated with eastern equine encephalitis (EEE) virus or Highlands J (HJ) virus; semen was examined for presence of virus and ability to transmit infection by artificial insemination. Mild depression and inappetence were observed in tom turkeys inoculated with either EEE virus or HJ virus. Toms were viremic on days 1-2 postinoculation (PI), and virus was shed in semen on days 1-5 PI. Semen collected from EEE-virus-inoculated or HJ-virus-inoculated toms on days 1-2 PI and inseminated into turkey breeder hens transmitted the infection. EEE virus was detected in one of 10 hens after insemination with semen from EEE-virus-inoculated toms, and HJ virus was detected in three of 10 hens after insemination with semen from HJ-virus-inoculated toms. These results indicate that semen is a potential vehicle for transmission of EEE virus and HJ virus.

Alphavirus Infections↗

PubMedDate not supplied

Decreased egg production in turkeys experimentally infected with eastern equine encephalitis virus or Highlands J virus.

Turkey breeder hens were experimentally infected with strains of eastern equine encephalitis (EEE) virus or Highlands J (HJ) virus previously isolated from turkey hens experiencing decreased egg production. Depression and inappetance were observed on day 1 postexposure (PE) in hens inoculated with either EEE virus or HJ virus, and egg production fell in each virus-inoculated group from approximately 75% to less than 20% within 2-3 days PE. Egg production remained depressed (less than 20%) for 15 days in EEE-virus-inoculated hens and for 7 days in HJ-virus-inoculated hens. EEE virus and HJ virus were recovered from various tissues on days 1-5 PE, and virus was detected in eggs laid on days 2-5 PE. The findings of this study confirm that EEE virus and HJ virus are potential causes of decreased egg production in turkey breeder hens.

Alphavirus Infections↗

PubMedDate not supplied

Experimental infection of young broiler chickens with eastern equine encephalitis virus and Highlands J virus.

Two-week-old broiler chickens were experimentally infected with either eastern equine encephalitis (EEE) virus or Highland J (HJ) virus. Mortality rates were 24/30 (80%) in EEE-virus-inoculated chickens and 2/30 (7%) in HJ-virus-inoculated chickens. Chickens inoculated with EEE virus exhibited severe depression and somnolence on days 1-6 postexposure (PE), with 17/30 birds dying during this period. After day 6 PE, EEE-virus-inoculated chickens exhibited abdominal distention, depression, and growth retardation, and an additional seven chickens died. Pathologic changes in EE-virus-inoculated chickens dying on days 1-6 PE consisted of multifocal necrosis in the heart and liver, as well as lymphoid depletion and necrosis in the thymus, spleen, and bursa of Fabricius. Ascites, pericardial effusion, and right ventricular dilatation of the heart were the predominant lesions in chickens dying after day 6 PE. No clinical signs were observed in sham-inoculated controls or in most HJ-virus-inoculated chickens. Ascites, pericardial effusion, and multifocal myocardial necrosis were observed in 2/30 HJ-virus-inoculated chickens that died or were euthanatized after development of clinical signs. These findings indicate that both EEE virus and HJ virus are pathogenic for young chickens.

Alphavirus↗

PubMedDate not supplied

Coumafuryl (Fumarin) toxicity in chicks.

Coumafuryl (Fumarin) toxicity was diagnosed in chickens less than 1 week of age. Mortality rate was 100%. Necropsy showed crops and gizzards to be full of feed. There was diffuse hemorrhage and unclotted blood in the abdomen and thorax. Histological examination showed congestion and hemorrhage. Chemical analysis of crop and gizzard contents contained approximately 340 ppm coumafuryl. The source of the coumafuryl was found to be the wood-straw mats in the chick boxes.

4-Hydroxycoumarins↗

PubMedDate not supplied

Experimental infection of young turkeys with eastern equine encephalitis virus and highlands J virus.

Depression, somnolence, and increased mortality were observed in 2-week-old turkeys inoculated intramuscularly with either eastern equine encephalitis (EEE) virus or Highlands J (HJ) virus. Mortality rates in EEE virus- and HJ virus-inoculated turkeys were 7/30 (23%) and 9/30 (27%), respectively; no sham-inoculated controls died. Both EEE virus- and HJ virus-inoculated turkeys developed viremia that lasted 2 days; peak mean titers were 5.5 and 3.2 log10 plaque-forming units per ml of blood, respectively. Pathologic changes in both EEE virus- and HJ virus-inoculated turkeys consisted primarily of multifocal necrosis in the heart, kidney, and pancreas, and lymphoid necrosis and depletion in the thymus, spleen, and bursa of Fabricius. The findings indicate that EEE virus and HJ virus are pathogenic for young turkeys.

Alphavirus↗

PubMedDate not supplied

Efficacy of danofloxacin and tylosin in the control of mycoplasmosis in chicks infected with tylosin-susceptible or tylosin-resistant field isolates of Mycoplasma gallisepticum.

The efficacy of danofloxacin was compared with that of tylosin in the control of induced mycoplasmosis. In three experiments, disease was induced in broiler chicks by intrapulmonary injection of field isolates of Mycoplasma gallisepticum (MG) originating from Brazil, a different isolate being used for each experiment. Starting the day after inoculation, groups of chicks were medicated for 3 days via the drinking water with danofloxacin (50 ppm) or tylosin (500 ppm) or were left as unmedicated controls. Chicks were observed for 21 days. A severe mycoplasmosis was induced in unmedicated birds, characterized by mortality, depression, and respiratory signs. Danofloxacin was highly efficacious in controlling this infection in all three experiments, whereas tylosin was efficacious in only one. This difference could be related directly to the reduced in vitro susceptibility to tylosin displayed by the two isolates of MG. In the two experiments where isolates were tylosin-resistant, danofloxacin was significantly (P < or = 0.05) superior to tylosin in reducing mortality, maintaining weight gain, and reducing the prevalence of air-sac lesions, isolation of MG, and seroconversion.

Air Sacs↗

PubMedDate not supplied

A comparison of danofloxacin and tylosin in the control of induced Mycoplasma gallisepticum infection in broiler chicks.

Experimental mycoplasmosis was induced in 1-day-old chicks by intrapulmonary inoculation of Mycoplasma gallisepticum (MG). This method of infection proved to be useful for evaluating the efficacy of antimicrobial medication, by measuring mortality, weight gain, pathological responses, frequency of reisolation of MG, and seroconversion. Using this model, the efficacies of danofloxacin (a novel fluoroquinolone) and tylosin were compared for two MG isolates, a reference isolate (the R-strain) and a field isolate from California. Danofloxacin administered in the water at 50 ppm for 3 days was equivalent to tylosin at 500 ppm for 3 days in the degree of control of mortality and maintenance of weight gain. Danofloxacin was superior to tylosin in preventing air-sac lesions, reducing the frequency of reisolation of MG, and preventing seroconversion in surviving birds.

Air Sacs↗

PubMedDate not supplied

Experimental reproduction of severe hypoglycemia and spiking mortality syndrome using field-derived and embryo-passaged preparations.

The clinical signs, enteritis, weight depression, and hypoglycemia of spiking mortality syndrome were experimentally reproduced in broiler breeders and broiler chicks. Inocula included 1) virus-like particles from intestines of chicks with spiking mortality syndrome that had been banded in a discontinuous Renograffin gradient, 2) homogenized darkling beetles collected from litter of farms where spiking mortality syndrome had occurred repeatedly, and 3) homogenized embryos which had been inoculated with the Renograffin-banded material. Arkansas variant infectious bronchitis virus and arenavirus-like particles were identified in the inocula. Serology on samples from surviving chicks suggested the presence of an avian encephalomyelitis virus in one of the inocula. One-day-old (n = 172) and 2.5-day-old (n = 30) chicks were inoculated orally, and some were also injected intraperitoneally or subcutaneously, with 0.5 ml of the inocula. Twelve to fourteen days postinoculation, chicks were fasted for 4-6 hours, then briefly stressed with a cool water spray. Within 1.5 hours, inoculated chicks began dying with severe hypoglycemia and clinical signs of spiking mortality syndrome. Body weights were significantly depressed. Uninoculated controls (n = 130) from the same hatches, also fasted and stressed, were unaffected clinically and were not hypoglycemic. One group (n = 52) of inoculated chicks exposed to a controlled lighting program was unaffected clinically, had significantly higher mean plasma glucose levels, and had significantly less body weight depression than chicks exposed to continuous lighting. We concluded that exposure to controlled amounts of light/darkness can ameliorate much of the hypoglycemia, mortality, and runting-stunting associated with spiking mortality syndrome of chickens. The significance of the viruses and virus-like particles detected in the inocula is currently under investigation.

Animals↗

PubMedDate not supplied

Ultrasound for detecting osteomyelitis in turkeys.

One thousand turkey legs were examined for osteomyelitis (OM) by ultrasonographic, pathologic, and bacteriologic examinations. OM lesions were recognized as hyperechoic (brighter white) disruptions in cortical bone in the growth plate region by ultrasound examination OM was confirmed histologically in 139 of 1000 legs. OM was detected by ultrasound in 109 of 139 OM-positive legs for a sensitivity rate of 78%. OM was not detected by ultrasound in 713 of the 861 OM-negative legs for a specificity rate of 83%. Ultrasonography was superior to current use of green liver discoloration for detection of tibial OM in turkeys at processing. The economic benefit to the turkey industry from the approval and application of this procedure could be considerable.

Animals↗

PubMedDate not supplied

Transmissibility of live Mycoplasma gallisepticum vaccine strains ts-11 and 6/85 from vaccinated layer pullets to sentinel poultry.

In separate trials, layer pullets were vaccinated with Mycoplasma gallisepticum (MG) strain 6/85 or strain ts-11 commercially produced live vaccines. For a 15-wk postvaccination (PV) period, vaccinates were commingled with unvaccinated pullets and were in indirect contact with sentinel groups of pullets, broiler breeders, turkey breeders, or meat turkeys in adjoining pens. Infectivity and transmissibility of vaccine strains were determined by tracheal culture and serology at 1 wk followed by 3-wk intervals PV. Strain 6/85 was recovered from 0%-20% of vaccinates, but not from commingled pullets or sentinel birds. Strain ts-11 was recovered from 60%-90% of vaccinates and 0%-40% of commingled pullets but not from any of the sentinel birds. No birds in the 6/85 vaccine trial tested positive for MG antibodies by serology. MG enzyme-linked immunosorbent assays detected positive responses in ts-11 vaccinates (range = 10%-70%) at 42, 63, 84, and 105 days PV, and commingled pullets (10%) at 84 and 105 days PV. MG serum plate agglutination tests detected positive responses in 90% and 20% of ts-11 vaccinates at 42 and 105 days PV, respectively, and commingled pullets (10%) at day 42 PV. Clinical signs, morbidity, or mortality suggestive of pathogenic MG infection were not observed in any bird during either trial, and no gross lesions were observed at necropsy. Random amplified polymorphic DNA analysis was capable of distinguishing each of the vaccinal strains 6/85 and ts-11 from each other by their distinct DNA banding patterns.

Agglutination Tests↗

PubMedDate not supplied

Antigenic characterization of a turkey coronavirus identified in poult enteritis- and mortality syndrome-affected turkeys.

A turkey coronavirus (TCV [NC95]) was characterized by antigenic comparison with other avian and mammalian coronaviruses using immunofluorescence (FA) and immunoperoxidase (IP) procedures. Based on FA and IP procedures, TCV (NC95) was determined to be antigenically indistinguishable from turkey enteric (bluecomb) coronavirus (TECV). In addition, TCV (NC95) and TECV were found to be closely related to infectious bronchitis virus (IBV); a one-way antigenic relationship was demonstrated. Polyclonal antibodies specific for TECV and IBV reacted strongly against TCV (NC95), as determined by FA procedures. Monoclonal antibodies (MAbs) specific for IBV matrix protein (MAb 919) reacted strongly against TCV (NC95) and TECV as determined by FA and IP procedures; an IBV peplomer protein-specific MAb (MAb 94) did not recognize the two viruses. These studies suggest an identification of TCV (NC95) as a strain of TECV, and provide evidence of a close antigenic relationship between these viruses and IBV.

Animals↗

PubMedDate not supplied

Characterization of an avian adenovirus associated with inclusion body hepatitis in day-old turkeys.

A group I avian adenovirus isolated from day-old turkeys with inclusion body hepatitis (IBH) was identified as turkey adenovirus serotype 2 (TAV2) based on cross-neutralization assays and DNA restriction endonuclease analyses. Yolk sac inoculation of embryonated turkey eggs resulted in embryo mortality and significantly (P < 0.01) decreased hatchability compared with sham-inoculated controls. Embryo mortality occurred primarily between day 24 of incubation and the time embryos hatched. Focal necrosis was detected in livers of 11/52 virus-inoculated embryos that died postinoculation and 1/27 hatchlings; in three embryos, areas of necrosis contained intranuclear inclusion bodies. These findings identify the IBH isolate as TAV2, incriminate the virus as a potential cause of suboptimal hatchability in turkeys, and provide additional evidence for causal involvement in IBH.

Adenoviridae Infections↗

PubMedDate not supplied

Axillary cystadenocarcinoma in a Moluccan cockatoo (Cacatua moluccensis).

An adult Moluccan cockatoo (Cacatua moluccensis) was diagnosed with a cystadenocarcinoma in the right axillary region that was treated symptomatically with surgical debulking and periodic drainage. The bird eventually died and a necropsy was performed. The neoplasm extended through the humerus, and small neoplastic foci were seen within the ipsilateral lung parenchyma. Rare groupings of microvilli were observed lining intercellular canalicular lumens on electron microscopy within the axillary tumor. These findings suggest a respiratory neoplasm, although the tissue of origin remained undetermined.

Animals↗

PubMedDate not supplied

Alterations in the lymphocytic and mononuclear phagocytic systems of turkey poults associated with exposure to poult enteritis and mortality syndrome.

In vivo and in vitro mononuclear phagocytic system functions, expression of lymphocyte subset cell surface markers in the thymus and bursa of Fabricius, and lymphocyte subset dynamics during the course of poult enteritis and mortality syndrome (PEMS) were examined. PEMS is an acute, transmissible, infectious intestinal disease accompanied by high mortality and morbidity. The etiology of this multifactorial disease remains to be elucidated; however, turkey coronavirus was initially assumed to be one of the primary agents involved. Further investigation demonstrated that turkey coronavirus was not always detectable in poults exhibiting PEMS symptoms, and, thus, PEMS poults began to be identified as positive or negative for turkey coronavirus. In each trial, uninfected hatchmate controls were compared with turkey poults that were contact exposed to PEMS poults at 7 days of age. Following intravenous inoculation, control poults cleared Escherichia coli from their circulation by 60 min, whereas viable E. coli were still present in the circulation of PEMS poults at 60 min postinoculation. Inflammatory response measured by Sephadex-elicited abdominal exudate cell recruitment and the adherence potential of abdominal exudate cells was not significantly different between uninfected and PEMS poults. The percentage of glass-adherent abdominal exudate macrophages was higher in PEMS poults. However, the ability of these macrophages to phagocytize sheep red blood cells and the average number of sheep red blood cells per phagocytic macrophage were both lower compared with uninfected controls. CD4+ expression in thymic tissue of PEMS poults at 9 days postinfection was significantly lower. The CD4+:CD8+ lymphocyte ratio in peripheral blood leukocytes from coronavirus-negative PEMS poults was lower than that from both uninfected and coronavirus-positive PEMS poults at 14 days postinfection. In the spleen, the CD4+:CD8+ lymphocyte ratio was higher in coronavirus-positive PEMS poults as compared with the other treatments. In conclusion, immune system dysfunction in PEMS is associated with impaired mononuclear phagocytic system function and alterations in lymphocyte populations.

Animals↗