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Experiments were carried out on 20 geese, aged 6 months, affected with mixed infection of Amidostomum anseris, Capillaria anatis and Heterakis gallinarum. Ten experimental geese were twice disinfested at 10-day intervals and vaccination of the geese with a prepared DERVAC vaccine was performed 7 days after the second disinfestation, four weeks before laying period. The presence af antibodies was determined by ELISA. Sera with an optical density greater than 0.2 were considered positive. Experiments were carried out on four groups of geese, each composed of five birds: group I - geese infected and vaccinated with DERVAC vaccine; group II - geese infected and vaccinated; group III - geese infected and unvaccinated; and group IV - geese infected and unvaccinated. Coproscopic examinations were carried out twice a week for the whole experimental period. Blood samples for anti-DDV seroconversion were collected before vaccination nad next at 3-week intervals after vaccination, until the 21-st week of the experiment. The results of the experiment showed that even symptomless nematode infection caused by Amidostomum anseris, Capilaria anatis and Heteraks gallinarum in vaccinated geese, with prevalence of Amidostomum anseris, induced significantly delayed antibody production. Antibody level in infected geese at the 40th week after infection was significantly lower than that in the dehelminthized birds; therefore., it is recommended to examine parasitologically reproduction flocks of geese before their vaccination against DD and to perform disinfestation if infection with nematodes is found.
Vaccine B-38 strain of Derzsy’s disease virus (DDV) was used in the study. The virus was lyophilized after the multiplication in the culture of GEF. Sucrose — glutamine, gelatine — sucrose, peptone — lactose and SPGA solutions were applied as stabilizators. The lyophilizates were kept at 4°C for 24 months. The concentrations of the virus in the samples were estimated periodically. It was found that peptone — lactose stabilizator was the most effective protector of DDV from inactivation. The virus was dissolved in Eagle’s fluid, PBS and commercial solvent. The dissolved vaccine was kept at 4°C, 21°C and —20°C for 24 h. The titre of the vaccine was determined immediately after the dissolving and then after 2, 4, 6 and 24 h. Storage of the vaccine at 21° or 4°C for more than 2 h resulted in a significant drop of its titre. Eagle’s fluid used as a disolvent did not differ significantly from the commercial solvent.
The aetiological agent of Derzsy’s disease is a parvovirus (GPV) belonging to the Parvoviridae family, genera Dependovirus. Currently, the mortality rate of Derzsy’s disease is much lower than it was before the introduction of vaccination. The most common form is the chronic one. Therefore, cases of Derzsy’s disease in geese in 1998-2011 were analyzed. The study was carried out in 122 bird flocks. The number of birds in the flocks ranged from 1,200 to 12,000, and most flocks consisted of 3,000-5,000 geese. Most goslings in the flocks were 2-5 weeks old. The presence of antibodies against GPV was detected in all flocks of birds up to 5 weeks of age. The first symptoms, such as reluctance to eat and drink, difficulty in locomotion, paralysis and diarrhoea, usually appeared in the first two weeks of life. The mortality of geese in each year ranged from 13.95% to 42.45%. Among the geese examined, the most frequent pathological changes were observed in the liver, in the form of oedema (22%) and hyperaemia (41%). In 33% of geese a significant degree of emaciation was noted. Derzsy’s disease was confirmed by the PCR detection of the virus in the visceral organs in 36 of the flocks examined. Derzsy’s disease was reported most frequently in the following voivodeships: Greater Poland, Podlaskie, Lublin, Lower Silesian, and Lubusz. In these areas, despite annual prophylactic vaccination, Derzsy’s disease was observed in geese aged 1- 6 weeks, usually between 2.5-3.5 weeks of age. Additionally, using the multiplex PCR, a mixed infection with GPV and goose circovirus was found in 6 flocks. Research aimed at developing a recombinant vaccine against Derzsy’s disease and a new enzymatic ELISA was started last year. To sum up, the analysis of the results shows that Derzsy’s disease remains a health threat in young goose flocks.
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