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1.
Conventionally raised chickens were inoculated with a local isolate of serotype 8 of avian adenovirus by an oral or intraperitoneal route, or were exposed to the infection by contact. Fatal hepatitis, resembling inclusion body hepatitis, occurred in 30% and 45% of the birds inoculated by the oral and intraperitoneal routes respectively, and severe growth depression was recorded in survivors and in birds in contact. Birds which had maternally derived virus neutralising antibody titres of 64 or greater at the time of viral exposure did not succumb to fatal infection, but their growth rates were significantly depressed. 相似文献
2.
MD Saifuddin T. I. M. F. R. Chowdhury A. J. Sarker M. M. Amin 《Tropical animal health and production》1990,22(4):263-272
Summary An evaluation was undertaken of the efficacy of vaccination of day-old chicks with the Blacksburg (B1) strain of Newcastle disease virus (NDV) followed at various times by vaccination with the Komarov (K) strain. Antibody was detected by the haemagglutination inhibition (HAI) test one week after vaccination with B1 and titres peaked at three weeks and had declined to undetectable levels by nine weeks.After subsequent vaccination with K strain at five, seven or eight weeks of age levels of HAI antibody (titre 80 to 640) were detected after three weeks. Birds vaccinated at seven weeks were tested for antibody and resistance to challenge beyond 19 weeks of age. In this group the HAI titres remained constant (80 to 640) up to 32 weeks of age and then steadily declined to 10 to 20 at 44 weeks of age.A linear relationship between HAI titre and virus neutralising index (VNI) was demonstrated with a range of selected sera. Only birds with an HAI titre of 80 or greater resisted artificial challenge. It is recommended that, following B1 vaccincation at day-old and K vaccination at seven weeks old, revaccination with K strain should be performed at intervals of not more than seven months.
Proteccion Conferida Mediante Vacunacion Con Las Cepas Blacksburg Komarov Del Virus De Newcastle En Bangladesh
Resumen Se llevó a cabo una evaluación de la eficacia de la vacunación de pollitos de un día, con la cepa Blacksburg (B1) del virus de la enfermedad de Newcastle, seguida de varias aplicaciones vacunales periódicas con la cepa Komarov (K). Se detectaron anticuerpos mediante la prueba de inhibición de la hemaglutinación, una semana después de la vacunación con B1, los títulos alcanzando el pico a las tres semanas y declinaron a niveles no detectables a las nueve semanas.Después de aplicaciones vacunales periódicas con la cepa K, a las cinco, siete u ocho semanas de edad, se detectaron anticuerpos mediante la prueba de inhibición de la hemaglutinación (títulos 80 a 640), después de tres semanas. Las aves vacunadas a las siete semanas, recibieron una descarga y se les hizo prueba de anticuerpos, después de las 19 semanas de edad. En este grupo los títulos de anticuerpos permanecieron constantes (80 to 640) hasta las 32 semanas de edad y después declinaron lentamente a 10 ó 20 a las 44 semanas de edad.Se demostró una relación lineal entre los títulos hallados y el índice viral neutralizante, en un rango de sueros seleccionados. Solamente las aves con títulos de 80 o más altos resistieron la descarga artificial. Se recomienda que, seguidamente a la vacunación con B1 a un día de edad y con K a las siete semanas, las revacunaciones con la cepa K debería hacerse con intervalos de no más de siete meses.
Protection Conferee Contre La Maladie De Newcastle Au Bangladesh Par La Vaccination A L'Aide Des Souches Blacksburg Et Komarov De Virus De La Maladie De Newcastle
Résumé Une evaluation de l'efficacité de la vaccination de poussins d'un jour à l'aide des souches Blackburg (B1) du virus de la maladie de Newcastle, suivie à différents moments par la vaccination à l'aide de la souche Komarov (K), a été entreprise. Les anticorps furent détéctés par inhibition de l'hemagglutination (HAI), une semaine après la vaccination avec la souche B1 et le titre atteignit un pic à 3 semaines pour décliner jusqu'à des niveaux indétectables à neuf semaines. A la suite de vaccinations consécutives avec la souche K à cinq, sept ou huit semaines, les niveaux d'anticorps HAI furent détectés après trois semaines. Les oiseaux vaccinés à sept semaines furent examinés pour les anticorps et la résistance à une épreuve au delà de 19 semaines d'âge. Dans ce groupe les titres HAI sont restés constants (80 à 640) jusqu'à l'àge 32 semaines, puis ont diminué régulièrement jusqu'à 10 à 20 à l'âge de 44 semaines.Une relation linéaire entre le titre HAI et l'index de neutralisation du virus (VNI) a été démontrée sur une gamme de sérums choisis. Seuls les oiseaux ayant un titre HAI de 80 ou plus ont résisté à l'épreuve artificielle. On recommande que, après une vaccination B1 à un jour, et une vaccination K à l'âge de sept semaines, une revaccination K soit réalisée à des intervalles n'excédant pas sept mois.相似文献
3.
A reovirus was isolated from a flock of 12,000 broiler chickens which experienced a total mortality of 6.3% up to 35 days. The reovirus produced large syncytia in primary chicken kidney cell cultures with eosinophilic intracytoplasmic inclusion body formation. Infected cells reacted with fluorescein conjugated specific anti-reovirus serum. Negatively strained virions had a double shelled appearance with overall diameter of 65 to 70 nm. The nucleic acid had ten discrete segments with electrophoretic mobilities as would be expected for a reovirus. 相似文献
4.
An immunocytochemical technique utilizing an avidin-biotin peroxidase complex was developed to detect viral antigens in various tissues following oral administration of a locally isolated serotype 8 avian adenovirus (AAV) in specific pathogen-free (SPF) chickens. A strong color reaction was obtained with tissues from infected birds that contained a minimal amount of AAV antigens as determined by an indirect enzyme-linked immunosorbent assay. No reaction was detected in sections of tissues obtained from SPF chickens, and the reactivity with infected tissues could be removed by prior absorption of the primary antibody with purified AAV. A group-specific antigen common to the 12 serotypes of AAV was demonstrated by this technique. Because of the high sensitivity and broad-spectrum reactivity, this technique could be useful for studying the pathogenesis and laboratory diagnosis of inclusion body hepatitis caused by several serotypes of AAV. 相似文献
5.
The present study was aimed at the identification of treatment optima to induce triploidy in ‘Labeo rohita (rohu) × Cirrhinus cirrhosus (mrigal)’ hybrid using heat shock treatment. The eggs were exposed at four different temperature regimes viz., 38, 39, 40 and 41°C for 1–3 min, applied 3–5 min after fertilization. After 4 min of fertilization, heat shock treatments for 1 and 1.5 min durations were found the best inducing triploidy up to 100% and 96% respectively. Survival rates upto yolk sac absorption were found to be 73% and 71% in rohu and mrigal, 68% and 67% in the reciprocal diploid hybrids and 61% and 60% in the reciprocal triploid hybrids (RTH). Triploidy was confirmed by chromosome counting that revealed the diploid chromosome number of rohu and mrigal at 2n = 50 and in their triploid hybrid chromosome number was found to be 3n = 75. Growth rate of the RTH showed a significant difference (P < 0.05) from the single species and the diploid hybrids. Triploids also showed higher survival rate over the diploids. 相似文献
6.
Using an indirect enzyme-linked immunsorbent assay, avian adenoviral antigens were detected in the yolk and albumen of eggs derived from broiler breeder chickens which were known to be infected with a strain of virus capable of causing inclusion body hepatitis. Viral antigens were detected in egg yolk (16/60) more frequently than in the albumen (5/60). Direct detection of viral antigens in eggs strongly supports the hypothesis that transovarian transmission of inclusion body hepatitis virus occurs if infection is present in breeder flocks. 相似文献
7.
Eleven avian adenoviruses were isolated in monolayer cultures of specific pathogen free chicken kidney cells which were inoculated with suspensions of liver, intestine or bursa obtained from 15 broiler flocks experiencing outbreaks of inclusion body hepatitis (10 isolates) and from five unaffected flocks (one isolate). Of the 11 isolates obtained, nine were identified by virus neutralisation tests as serotype 8, one as serotype 1 and one as serotype 12. Adeno-associated viruses were only observed in combination with adenoviral particles of the serotype 12 isolate which was derived from a relatively mild outbreak of inclusion body hepatitis. Only the serotype 1 isolate, obtained from the unaffected broiler flock, consistently caused the death of embryos with marked pathological changes. All of the isolates produced basophilic intranuclear inclusion bodies surrounded by clear halos in chicken kidney cell cultures. DNA preparations, obtained from six strains of serotype 8 avian adenovirus (two New Zealand isolates, three Australian isolates and the reference strain HVI) after digestion with the restriction enzymes EcoRI and BamHI, gave electrophoretic patterns showing the New Zealand isolates to be similar to one another and to strain HVI, but quite distinct from the Australian isolates. 相似文献
8.
Budi Winarto Nurhayati Ansori Mattjik Jaime A. Teixeira da Silva Agus Purwito Budi Marwoto 《Scientia Horticulturae》2010
Anther culture was successfully developed in Anthurium andreanum Linden ex André cv. ‘Tropical’, but resulted in variation in morphology and growth response of regenerants. Ploidy levels varied in different morphological variants. Finding a convenient, rapid, reliable, practical and indirect method to screen and determine anthurium ploidy level is important not only for anthurium, but for ornamentals in general. Regenerants derived from anther culture showing three different ploidy levels (haploids, diploids, triploids) were used in this study. Five indirect methods were used to assess chromosome number: chloroplast number in stomatal guard cells (M1), stomatal length and width ratio (M2), stomatal density (M3), ratio of length and width of leaves (M4), and microspore number per anther (M5). These were compared to chromosome counting as the direct and control method (M6). Through simple regression correlation analysis, when compared to M6, M1 was the most convenient and reliable indirect method to determine the ploidy level. This method was highly and significantly positively correlated to anthurium ploidy level (r = 0.945; p < 0.01). This method could also be applied much faster than the conventional chromosome method. 相似文献
9.
Md. Saifuddin B.W. Manktelow K.M. Moriarty N.H. Christensen M.J. Birtles 《New Zealand veterinary journal》2013,61(3):108-111
A study of the age-related functions of immunologically important components of the bursa of Fabricius in Shaver cockerels showed that endocytosis of carbon particles by the specialised follicle-associated epithelium was at a high level from hatching until 5 weeks of age and thereafter declined until at 18 weeks it could no longer be detected. The follicle-associated epithelium had marked non-specific esterase activity during the first 15 weeks of life as determined by a standard acid alpha-naphthyl acetate esterase method. The absolute weight of the bursa was at a maximum at 9 to 10 weeks. Involution began before 14 weeks and was complete by 22 weeks. The results indicate that the critical period for the bursa in regard to acquiring immunity from either local vaccination or environmental challenge is likely to be within the first five weeks of life. 相似文献