Effect of a variant infectious bursal disease virus (E/Del) on Salmonella typhimurium infection in commercial broiler chickens

The effect of infectious bursal disease virus (IBDV) on Salmonella typhimurium (ST) infections in broilers was investigated in terms of Salmonella shedding and persistence, pathogenicity, and isotype specific humoral immune responses. Thirty-six, 1-day-old, straight-run commercial broiler chickens that were Salmonella negative by polymerase chain reaction (PCR) and culture were divided into two groups of 18 chicks each (ST and ST-IBDV). One group (ST-IBDV) of chicks received the E/Del strain of IBDV (10(5.0) median tissue culture infective dose [TCID50]/ml) through the ocular and cloacal routes divided into doses of 50 microl each at 2 days of age. Both groups were then inoculated with 10(8) colony-forming units (CFU)/ml nalidixic acid-resistant ST in the drinking water at 3 days of age. Environmental Salmonella counts were higher in the ST-IBDV group at 2 and 3 wk postinfection (PI) compared to the ST group. ST carriage in the cecal contents between the ST and ST-IBDV groups was not statistically different. The ST-IBDV group had a single mortality at 10 days postinfection compared to none in the ST group. The ST-IBDV group had significantly lower bursa to body weight ratios at 4 and 6 wk, as well as higher bursal lesion scores than the ST group at 2, 4, and 6 wk PI. The ST group had significant increase in serum IgG from 2 to 6 wk PI in comparison to the ST-IBDV group, which had no significant changes over time. Both IgA and IgM were significantly increased at 4 and 6 wk relative to 2-wk levels. There was an IBDV-induced failure of anti-Salmonella IgG seroconversion over time in ST-IBDV. Both groups continued to shed high levels of Salmonella up to the end of the study despite high antibody levels in the ST group and an unimpaired IgM and IgA production in the ST-IBDV group, indicating a limited influence of humoral immunity on Salmonella clearance.     

A novel transcutaneous plasmid-dimethylsulfoxide delivery technique for avian nucleic acid immunization

In this report, we show that dimethylsulfoxide (DMSO) enhances liposome-mediated transfection of nucleic acid in chicken macrophage cells and that this could be exploited for the transcutaneous delivery of naked DNA through the intact skin of chickens. We found that DMSO enhanced transfection efficiencies of lipofectamine and polyethyleneimine in HD-11 chicken macrophage cells. Based on this principle, we showed that transcutaneous delivery of a DNA plasmid-dimethylsulfoxide mixture (1:1) to untreated skin of chickens results in a wide distribution of the plasmid in the body. Distribution studies were done using plasmids encoding enhanced green fluorescent protein (EGFP) reporter gene and a bivalent DNA vaccine coding for infectious bursal disease virus (IBDV) and Newcastle disease virus (NDV) immunogenic protein genes. This bivalent vaccine induced mucosal and systemic immune responses, as evidenced by IgA and IgM production in the tears and serum of vaccinated chickens. Mucosal immune responses in the tears after topical vaccination were significantly higher (P < 0.05) than after i.m. delivery of the same DNA vaccine and were characterized by the absence of an IgG response. The biodistribution of plasmid indicated that topical delivery with DMSO resulted in a wide distribution and persistence of the plasmid until 15 weeks post-primary vaccination. Both delivery methods resulted in insert-specific message being made in several body tissues, but after topical delivery the virus-specific mRNA could be detected in the bone marrow of one out of three chickens until 15 weeks post-primary vaccination. Furthermore, transcutaneous delivery of this DNA vaccine using DMSO conferred protection from challenge with virulent IBDV (86% survival) and NDV (86% survival). This novel transcutaneous method of delivery of a DNA vaccine shows promise as being an easy and effective way to deliver nucleic acids through intact skin for vaccination or therapeutic purposes.     

PATHOGENICITY AND IMMUNOSUPPRESSIVE PROPERTIES OF INFECTIOUS BURSAL DISEASE VIRUS FIELD ISOLATES AND COMMERCIAL VACCINES IN INDIA

The pathogenicity and immunosuppressive properties of two field isolates of infectious bursal disease virus (IBDV) and five commercial IBDV live virus vaccines marketed in India were evaluated in this study. The pathogenicity of the wild type viruses and vaccines were based on mortality, the bursa:body weight ratio and microscopic lesions in the bursa in 3-week-old chicks that received these viruses. The immunosuppressive effects of these viruses were evaluated by measuring the antibody responses to sheep red blood cells, Brucella abortus plain antigen and Newcastle disease virus (NDV) vaccine in one-day-old chicks. One field isolate (N35/93) was found to be more pathogenic and immunosuppressive than the other (N45/92) while none of the commercial mild Lukert type vaccines were found to be pathogenic. One of the vaccine strains marked as Mild Lukert type was highly immunosuppressive; one was moderate and one could be classified as mild. Both the intermediate vaccines tested were highly immunosuppressive.     

Rocket Immunoelectrophoresis in the Diagnosis of Infectious Bursal Disease

The rocket immunoelectrophoresis (RIE) test was used for the qualitative detection and quantitative estimation of infectious bursal disease virus (IBDV) specific antigen in experimentally infected chickens and samples collected from suspected outbreaks. The IBDV specific antigen was detected in the bursae of experimentally inoculated chickens up to 5 days post infection (PI) by the agar gel precipitation (AGP) test and 7 days PI by the RIE test. The RIE detected IBDV specific antigen in a significantly greater number of samples collected from the field outbreaks than the conventional AGP test. Exudative bursae were found to have a higher antigen content than haemorrhagic bursae and are recommended as the material of choice for diagnosis of IBD. This test could also be used to quantify IBDV specific antigen in commercial killed vaccines.     

Quantitative counter-immunoelectrophoresis for estimation of antibodies to infectious bursal disease virus

Quantitative counter-immunoelectrophoresis was standardized to detect antibodies to the avian infectious bursal disease virus. This technique correlated well with the conventional quantitative agar gel precipitation test in estimating antibodies to IBDV. The use of blood dried on filter paper as an alternative to serum is discussed. QCIE is simple, easy to perform and faster than QAGP.Abbreviations AGP agar gel precipitation - CID₅₀ half-minimal chick infective dose - CIE counter-immunoelectrophoresis - EEO electroendosmosis - IBD infectious bursal disease - IBDV infectious bursal disease virus - QAGP quantitative agar gel precipitation - QCIE quantitative counter-immunoelectrophoresis     

Estimation of antibodies to Newcastle disease virus in tears

Summary Micro-haemagglutination inhibition tests (Micro-HI) were used to measure the level of maternal IgG in the tears of chicks and also to measure the levels of HI antibodies in the tears and serum after vaccination with F strain of Newcastle disease virus (NDV) and in the face of an outbreak of Newcastle disease. There was a 1·4 fold difference between the maternal IgG concentration in the serum and tears. The ratio of serum IgG to lachrymal IgG after maternal transfer was 4 to 5 : 1 on day 4 to 9 and decreased to 2·6 : 1 on day 12 post-hatch. The intra-ocular vaccination of chicks with F strain of NDV resulted in the highest titre of HI antibodies in the tears though there was no significant difference in the response of chicks vaccinated through intranasal, oral and intravenous routes.In the face of an ND outbreak, the level of HI antibodies in the tears during the acute phase was very high and persisted at the same level for 14 days.

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Determinacion De Anticuerpos Frente Al Virus De Newcastle En Lagrimas

Resumen Se utilizaron tests de inhibición de la microhemoaglutinación (micro-HI) para medir el nivel de IgG maternas en las lágrimas de pollitos y también para medir los niveles de anticuerpos HI en las lágrimas y en el suero después de vacunar con la estirpe F del virus de la enfermedad de Newcastle (NDV) y durante una epidemia de la enfermedad de Newcastle. Hubo una diferencia de 1·4 veces entre la concentración de IgG maternas en el suero y en las lágrimas. El cociente entre las IgG del suero y de las lágrimas tras la transferencia materna fue 4–5: 1 entre los días 4 y 9 y disminuyó a 2·6 : 1 el día 12 posteclosión. La vacunación intraocular de los pollitos con la estirpe F del NDV dió lugar al título más elevado de anticuerpos HI en las lágrimas, si bien las differencias entre animales vacunados por vía intranasal, oral y endovenosa no fueron significativas. Durante una epidemia de la enfermedad de Newcastle, el nivel de anticuerpos HI en las lágrimas durante la fase aguda fue muy alto y se mantuvo constante durante 14 días.

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Estimation Du Taux d'Anticorps Contre Le Virus De La Maladie De Newcastle Dans Les Larmes

Résumé Des tests d'inhibition par micro-hemoagglutination (Micro-Hi) furent utilisés pour mesurer, soit les taux d'IgG maternelles dans les larmes des poussins, soit les taux d'anticorps Hi dans les larmes et les sérums après vaccination avec une souche F du virus de la maladie de Newcastle (NDV) et dans le cas d'une épidémie de la maladie de Newcastle. Le ratio entre les IgG maternelles dans le sérum et les larmes fut de 1,4. Le ratio entre les IgG dans le sérum et les IgG dans les larmes était de 4 à 5 pour 4 entre le jours 4 et 9 et diminua à 2,6; 12 jours après éclosion. La vaccination intra-oculaire des poussins avec une souche F du virus de la maladie de Newcastle donna les plus hauts taux d'anticorps Hi dans les larmes, cependant il n'y eut pas de différence significative dans la réaction des poussins après vaccination intranasale, orale ou intraveineuse.Durant une épidémie de la maladie de Newcastle, le niveau des anticorps Hi dans les larmes pendant la phase auguë fut très élevé et persista à ce niveau pendant 14 jours.

     

Evaluation of an immunochromatography strip assay for the detection of Salmonella sp. from poultry.

The present study was conducted to evaluate the sensitivity and specificity of an immunochromatography-based diagnostic kit for Salmonella. The analytical sensitivity of the test when using pure colonies of different Salmonella species was in the range of 1 X 10(4) to 1 x 10(5) colony-forming units per milliliter. The strip detected 19 of 22 strains of Salmonella spp. but failed to detect S. worthington, S. choleraesuis var. kunzendorf and S. johannesburg. The strip did not detect 27 different enteric bacteria, including Escherichia coli O157:H7, Campylobacter jejuni, Shigella sonnei, and Vibrio parahaemolyticus. In direct testing of feces (n = 66) from chickens infected with Salmonella typhimurium, the strip had a sensitivity of 12.3% and a specificity of 100%. Evaluation of the strip assay (n = 510) after sample pre-enrichment in 2% buffered peptone water (BPW) yielded a sensitivity of 93.8% and specificity of 89% when compared to isolation and identification with xylose-lysine-tergitol 4 (XLT4) selective plating media. Subsequent enrichment in Hajna tetrathionate (TT) broth yielded a higher sensitivity (94.7%) and specificity (96.8%). The agreement (kappa) between the strip test and isolation was 0.004 in direct fecal testing, 0.82 in BPW, and 0.89 in TT broth. The assay could detect Salmonella sp. as early as 18-48 hours during pre-enrichment and enrichment compared to isolation on XLT4, which required an overnight incubation step for the presumptive isolation and identification of Salmonella.     

DNA vaccination in the avian

The skin has long been recognized as a major producer of cytokines, but the keratinocyte as principal epidermal cell has received less attention as potential source and target of cytokines. Nevertheless, keratinocytes produce a plethora of cytokines including interleukin (IL)-1, -6, -7, -8, -10, -12, -15, -18, and -20, and tumor necrosis factor alpha (TNF). The production by keratinocytes of pro-inflammatory (IL)-1, -6, -8, and TNF was recognized early and is well studied. Keratinocyte-derived IL-7 and -15 are considered to be significant in T-cell trafficking, possibly even in the pathogenesis of cutaneous T-cell lymphoma. Immunomodulatory IL-10 and -12 originating from keratinocytes are considered to be responsible for systemic effects, and IL-18 perhaps has a similar action. Keratinocytes were fairly recently recognized as being source or target of other IL-10 family members like IL-20 and IL-24 and the role of these cytokines in specific diseases is under investigation. In addition, a variety of cytokine receptors are present on keratinocytes like those for IL-4, -13, and -17 and to lesser degree IL-2. The ability to study the expression of cytokines by keratinocytes in vivo and in vitro using primary cells, immortalized cells or even organotypic culture systems offers many possibilities to further investigate the role of cytokine production in keratinocyte biology and disease.