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H D Stone

Publications and source records attributed to H D Stone.

At least 19 recordsLinked to original sources
PubMed2003

Detection of Salmonella enteritidis-specific immunoglobulin A antibodies in crop samples from chickens infected with Salmonella enteritidis.

The crop (ingluvies), an organ for food storage in most avian species when the proventriculus is full, is located at the base of the esophagus. Little is known about any immunological capacity in the crop, and the current study was conducted to determine whether any antibodies to SE could be found in crop flushes taken from White Leghorn hens following infection with this organism. Surprisingly, an exceptionally strong IgA anti-SE response could be detected in the crops of hens 17 d postchallenge, and a comparison at Day 22 of crop vs. intestinal IgA anti-SE responses showed a good correlation between anti-SE antibody levels in the two regions. Histologic examination of crop tissues revealed development of lymphoid aggregates in the crop walls following challenge with SE. These results indicate that the crop may serve a role in immune protection in addition to its capacity as a food storage organ.

Animals↗
PubMed2003

Detection of Salmonella enteritidis in incubated pools of egg contents by fluorescence polarization and lateral flow immunodiffusion.

Efficient detection of Salmonella enteritidis inside eggs is critical for confirming that individual commercial laying flocks present a risk to public health. In most standard bacteriological culturing protocols, an initial incubation step is necessary to allow the typically very small population of S. enteritidis cells in pools of egg contents to multiply to more easily detectable levels. In the present study, two rapid methods were evaluated as alternatives to plating on selective media for detecting S. enteritidis in incubated egg pools. By using either fluorescence polarization or lateral flow immunodiffusion assays, S. enteritidis could be consistently detected in egg pools at 10(8) cfu/mL (and in most pools at 10(7) cfu/mL). Although the rapid assays were significantly less sensitive than culturing, they both were consistently able to detect contamination when pools of 10 eggs were inoculated with approximately 10 cfu of S. enteritidis and incubated for 72 h at 25 degrees C.

Animals↗
PubMed2002

Detection of experimental Salmonella enteritidis and S. typhimurium infections in laying hens by fluorescence polarization assay for egg yolk antibodies.

Identifying infected laying flocks is a critical component in efforts to prevent eggborne transmission of Salmonella enteritidis to humans. In the present study, egg yolk samples from experimentally infected chickens were tested for specific antibodies with a very rapid fluorescence polarization assay using tracers prepared from the O-polysaccharides of S. enteritidis and S. typhimurium and a conventional ELISA using an S. enteritidis flagellin antigen. In two trials, groups of specific-pathogen-free laying hens were infected orally with 106 or 10(8) cfu of S. enteritidis (phage type 13a) or with 10(8) cfu of S. typhimurium. Eggs were collected during five weekly postinoculation intervals. Both fluorescence polarization and ELISA detected the majority of hens infected with S. enteritidis at either dose level, although they also frequently cross-reacted with samples from hens infected with S. typhimurium. Fluorescence polarization with an S. typhimurium tracer was likewise able to consistently detect S. typhimurium infection but also tended to cross-react with samples from hens infected with S. enteritidis. Fluorescence polarization appears to offer a simple and rapid alternative to conventional serological methodology, although concerns about specificity may limit the usefulness of antibody testing data.

Animals↗
PubMed2000

Application of the agar gel precipitin test to detect antibodies to Salmonella enterica serovar enteritidis in serum and egg yolks from infected hens.

Serological surveillance can be an important component for egg quality assurance programs geared toward controlling problems with Salmonella enterica serovar Enteritidis (S. enteritidis) within a flock. Serum is the primary sample source for the procedures, although egg yolk antibody assays have become popularity in recent years. However, these assays tend to be labor intensive, requiring procedures for extracting antibodies from the yolk followed by assaying the samples. We describe an adaptation of the agar gel precipitin (AGP) test for use in detecting antibodies to S. enteritidis deposited in egg yolks of infected hens. Yolk or sera from infected birds were administered to wells cut into seven-well clusters in an agar gel plate, and detection antigen was added to the center well. The agar gels were incubated for 24 h and then examined for the presence of precipitin lines formed by the interaction of antibody with antigen. Three different antigens were tested: S. enteritidis flagella, SEF14 (a 14-kDa fimbrial protein produced ostensibly by S. enteritidis), and a sodium deoxycholate extract of whole S. enteritidis organism. Flagella and the organism extract detected antibodies to S. enteritidis in the yolk and sera, whereas SEF14 was not reactive. Positive reactions were observed in serum 1 wk postchallenge, whereas in yolks, this was further delayed by 1 wk. The sensitivity of the test was slightly less than the standard microagglutination assay, although specificity was slightly higher, as indicated by results from sera and yolks from birds infected with Salmonella enterica serovar Typhimurium. Simplicity and low labor requirements of the assay would allow for the potential testing of several hundred egg samples within a day, which would make up for test shortcomings due to sensitivity. The AGP test could be an important tool for individuals using serological testing to monitor the S. enteritidis situation within their flocks or as a rapid screen for vaccine responses. The assay could also be used in tandem with other AGP tests to screen for the presence of multiple avian pathogens.

Animals↗
PubMed1999

Hyporesponsiveness of the systemic and mucosal humoral immune systems in chickens infected with Salmonella enterica serovar enteritidis at one day of age.

Newly hatched chicks lack immunological maturity, which could compromise their ability to respond to infection by pathogens such as Salmonella enterica serovar enteritidis (S. enteritidis; SE). A study was conducted in which chicks were infected with a sublethal dose of SE at 1 d posthatch, and the systemic and intestinal immune responses to the challenge were followed over time. Birds infected at this age experienced difficulty in clearing the infection, and 50% of the individual birds remained persistently infected until 23 wk of age. These birds exhibited only a marginal systemic and mucosal humoral immune response to the infection. No response or little response was observed 1 wk postchallenge; responses increased somewhat over time. On many of the sampling times, 50% or more of the culture-positive birds lacked a detectable plasma or intestinal response. Levels of 10(3) to 10(5) SE/g of feces could be found in the intestines of birds eliciting a good IgA response, indicating that, when these birds did respond mucosally, the IgA produced was incapable of clearing the organism once the infection was established. Birds infected during this time also experienced reduced ability to respond to vaccination. Compared with uninfected controls, depressed responsiveness to an S. enteritidis bacterin was observed in infected birds 1 and 2 wk after administration, whereas those individuals receiving an inactivated Newcastle disease vaccine (NDV) experienced a reduced response 4 and 6 wk postvaccination, indicating that the persistent infection affected the ability of the immune system to respond to homologous and heterologous antigens. These results demonstrate that exposure of chickens to SE early in life interferes with the ability of these individuals to respond humorally to the infection and to other antigenic stimuli; such effects can be observed for at least 23 wk.

Animals↗
PubMed1994

Human immunodeficiency virus-associated nephropathy: current concepts.

A distinct form of renal disease has been described in patients at various stages of HIV infection that is becoming increasingly important as a cause of morbidity and mortality. Black race and intravenous drug abuse appear to predispose one to its development. The HIV-associated nephropathy is characterized by nephrotic-range proteinuria, rapid progression to end-stage renal disease, a diffuse sclerosing glomerulopathy with significant tubulo interstitial disease seen on light microscopy, and tubuloreticular inclusions seen via electron microscopy. The entity can be separated from heroin-associated nephropathy. The pathogenesis is unclear. Possibilities include direct invasion of the virus, effects of other viruses, genetic factors, immune factors, and multiple growth factors. Not all patients with HIV infection and renal disease have HIV-associated nephropathy. Because of prognostic and therapeutic implications, it is crucial to differentiate these lesions. Some reports suggest a possible beneficial effect of zidovudine therapy, but more study is required. Patient survival is dependent on the stage of HIV infection. Dialysis therapy does not appear to substantially prolong life in most patients with AIDS and irreversible renal failure. Therefore, a number of ethical issues have arisen that deal with medical futility.

AIDS-Associated Nephropathy↗
PubMed1983

Comparison of inactivated Newcastle disease viral vaccines containing different emulsion adjuvants.

Chickens inoculated with inactivated-virus Newcastle disease vaccines containing different emulsion adjuvants were challenge exposed with viscerotropic velogenic Newcastle disease virus. Adjuvant activity was evident in all of 9 vaccines containing mineral oil emulsion (OE), but was not evident in 2 vaccines which contained a metabolizable lipid emulsion (LE) adjuvant consisting of peanut oil, glycerol, and lecithin. Serologic responses of chickens inoculated with OE vaccines were 10- to 100-fold higher than those of chickens inoculated with LE vaccines. One of 106 chickens given OE vaccine, 12 of 24 given LE vaccine, and all of 24 nonvaccinated control chickens were clinically affected or died after challenge exposure. Five OE vaccines emulsified only by brief vigorous shaking had adjuvant activity similar to 4 OE vaccines emulsified by conventional homogenization.

Adjuvants, Immunologic↗
PubMed1979

Immunization of chickens and turkeys against avian influenza with monovalent and polyvalent oil emulsion vaccines.

Chickens and turkeys vaccinated with inactivated virus oil-emulsion vaccines containing different concentrations of either 1 (monovalent) or 4 (polyvalent) strains of avian influenza virus (AIV) were challenged-exposed with virulent AIV A/chicken/Scotland/59 or A/turkey/Ontario/7732/66. Four of 6 vaccines protected completely against postexposure mortality. Vaccine valency did not alter the serologic and challenge-exposure responses of chickens vaccinated with AIV A/turkey/Wisconsin/68, which was the virus component common to both monovalent and polyvalent vaccines. The magnitude of the serologic responses and protection against challenge-exposure were dependent on the concentration of virus in the vaccines. These data indicate that control of virulent AIV in chickens and turkeys by vaccination with inactivated vaccines may be feasible.

Animals↗
PubMedDate not supplied

Viscerotropic velogenic Newcastle disease in turkeys: immune response following vaccination with either viable B1 strain or inactivated vaccine.

When used as a vaccine, live letogenic B1 Newcastle disease virus (NDV) protects turkeys against challenge-exposure to viscerotropic velogenic NDV (VVNDV). Low-level passively-immune poults were vaccinated one, two, or three times at various intervals and their immunity challenged at various times from 1 to 10 months of age. Newcastle disease virus was isolated readily from either the blood, trachea, or vent of turkeys in all challenge groups (through 5 months of age) on the 3rd to 6th days postchallenge (PC) but after 14 days PC was isolated rarely. Virus was isolated from turkeys that had high titers of serum hemagglutination-inhibition antibodies at the time of challenge. The anamnestic antibody response appeared to be stronger in poults that had low antibody titers prior to challenge-exposure to VVNDV. In a small-scale study with an inactivated VVNDV vaccine, vaccinated poults were protected against challenge with the homologous viscerotropic virus. Parallel control studies on the infectivity of viscerotropic NDV for turkeys indicated that resistance to VVNDV increased with age.

Administration, Oral↗
PubMedDate not supplied

Viscerotropic velogenic Newcastle disease in Turkeys: virus shedding and persistence of infection in susceptible and vaccinated poults.

Susceptible turkeys and turkeys vaccinated with live lentogenic B1 strain Newcastle disease virus (NDV) were inoculated intracularly with viscerotropic velogenic (VV) Fontana strain NDV and studied for virus shedding and persistence of infection. Susceptible poults that survived infection (15%) continued to shed NDV from the intestinal tract up to 46 days postinoculation. Turkeys that were vaccinated with B1 strain NDV did not develop clinical signs when their immunity was challenged with VV Fontana strain virus. Virus was covered up to 53 days postchallenge (PC) from the cloaca of poults that were vaccinated once at 4 days of age and challenged at 1 month of age. Older turkeys that had been vaccinated one to three times did not generally shed virus after 4 days PC. Newcastle disease virus was recovered later in convalescence by the organ-culture method when swabs of trachea and cloaca were negative for virus. Persistent infection was detected as long as 88 days PC in organ cultures of cecal tonsil. Five of seven NDV isolants from organ cultures or from swabs caused fatal disease in chickens.

Administration, Oral↗
PubMedDate not supplied

Viscerotropic velogenic Newcastle disease in turkeys: isolation of Newcastle disease virus from tracheal and cecal tonsil organ cultures.

Tracheal and cecal-tonsil organ cultures were made from vaccinated turkeys that had survived challenge of immunity with viscerotropic velogenic strain of Newcastle disease virus (NDV). Culture fluids were tested to show that latent infections did exist in the vaccinated and challenged turkeys, thus indicating a possible carrier state. NDV was recovered from 6 of 159 turkeys examined. Preliminary tests indicate that 4 isolants are velogenic and 2 are lentogenic.

Administration, Oral↗
PubMedDate not supplied

Viscerotropic velogenic Newcastle disease in turkeys: vaccination against loss of egg production.

Live B1 Newcastle disease virus was administered to young turkeys either intraocularly or by driniking water, or by both methods. Protection against egg production loss was evaluated by challenge-exposure to viscerotropic velogenic Newcastle disease virus in drinking water. During 22 days postchallenge (PC), none of the vaccinated hens had morbidity, whereas 44% of the unvaccinated controls died 6-13 days PC. Percent egg production (PEP) of all groups 1-5 and 6-22 days PC were compared with their levels 1-5 days before challenge. For days 1-5 PC, changes were not significant. For days 6-22 PC, changes for all groups were siginficant lower. The controls had 0 production. Hens vaccinated only at 4 days or at 4 days and again at 4 weeks averaged one-third or less of prechallenge levels but were recovering. Those revaccinated at 4 months maintained 84-91% of their prechallenge levels and were considered satisfactory. Broodiness was a detracting factor in one group of hens vaccinated at 4 days, 4 weeks, and 51/2 months. They averaged two-thirds of prechallenge levels but were in decline.

Administration, Oral↗