[Multiple sclerosis, a virus disease; comparison with virus diseases of plants].
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The resistance effect on Newcastle disease virus (NDV) and Infectious Bursal Disease Virus(IBDV) in vitro of a new antimicrobial substance (AS), which produced by a Bacillus subtilis strain named B. subtilis fmbJ. Results showed that the TD50 and TD0 value of this AS on Chicken Embryo Fibroblasts cell (CEF) were 128.95mg/L and 25.79mg/L, respectively. This AS could strongly inhibit the cytopathic effects of cell induced by NDV as well as IBDV, and increase the survival rate of cell remarkably. This AS could inhibit the function of NDV and IBDV, and it could defend against the infection and inhibit multiplication of NDV and IBDV, and the effect was the same as the antiviral medicine Ribavirin. It had lower toxicity to CEF cell, therefore we would study it further that it was as antiviral medicine.
The genetic control of antibody (Ab) response to Escherichia coli (EC), infectious bursa disease virus, and Newcastle disease virus and the genetic and phenotypic correlation between these Ab responses, were evaluated under farm conditions in which chicks were simultaneously exposed to these antigens. The experimental population comprised five groups: two lines divergently selected for high (HH) or low (LL) Ab response to EC vaccination; a commercial broiler dam-line (CC), from which HH and LL had been derived; and the HH x CC and LL x CC hybrid groups (HC and LC, respectively). Lines LL and HH expressed similar symmetric divergence to all three antigens. The ranking of the LL, LC, CC, HC, and HH genetic groups according to their mean Ab responses and their very high linear correlation with the LL vs. HH genomic scale clearly indicate the additive nature of the genetic divergence between these lines. Several estimates of correlation were calculated between Ab responses of each pair of antigens and between BW and Ab to each antigen. The high correlation between group means, the near-zero within-group correlation, and the low phenotypic correlation indicate the strongly positive genetic correlation between Ab responses and no correlation with BW. The results of this study suggest that overall immunocompetence of commercial broilers can be improved by selection for high Ab response of young chicks to controlled immunization with a single antigen, without counteracting further selection for high BW.
Viruses of various biological types are known to cause a wide range of acute respiratory infections, ranging from mild colds and catarrh to severe bronchiolitis and pneumonia. Bacteria also cause respiratory diseases including serious conditions such as otitis media and pneumonia. The whole situation is complex and to understand the epidemiology we also need to consider nutrition, environment, climate, and chronic diseases. Acute respiratory viral diseases are very common in all areas of the world and contribute to morbidity and probably to mortality. There are no antiviral drugs or vaccines which would be generally useful. It ought to be possible to reduce the effects of these diseases by improving the standard of general management of cases. This would involve careful nursing, administration of appropriate antibiotics, and referral of severe cases to a properly staffed and equipped hospital. Further research is needed to develop ways of doing this and to evaluate the results.
For developing monoclonal antibodies against acute virus necrobiotic disease (AVND) virus, mice of Balb/c strain were immunized with AVND virions which were isolated from the infected scallop Chlamys farreri. The spleen cells from immunized mice were then fused with NS-1 myeloma cells and the hybridomas were screened by means of enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). Finally, 4 stable MAbs of IgG isotype were obtained. Moreover, the combined position of these 4 MAbs to this virus was examined by immunogold electron microscopy (IEM). The results demonstrate that all 4 MAbs recognized epitopes on the envelope of the virions. Subsequently, a MAb-based ELISA was developed and used for detection of the infection rate and densities of the scallops which were sampled during different seasons from mid-April to mid-October, 2003. The result exhibited that both of the infection rate and infection densities sharply rose in mid-July and reached to the spikes, which right corresponds with their mortality during this period.
Two approaches for simultaneous identification of both Foot-and-mouth disease virus (FMDV) and Swine vesicular disease virus (SVDV) are described: (1) a single-step reverse transcription-PCR with three primers and (2) a PCR-ELISA assay with two universal primers for genome amplification and two virus-specific probes for identification. These methods are based on the use of 3D gene universal PCR primers, the structure of which was optimized and refined due to the close relationship between the two viruses belonging to different genera of the Picornaviridae family. In procedure (1), a three-primer PCR containing one universal antisense primer and two virus-specific primers was shown to differentiate between FMDV and SVDV in one reaction, due to the different length of the amplified DNA fragments (600 and 340 base pairs, respectively). In procedure (2), the two viruses were identified by PCR-ELISA, i.e. PCR for the 3D gene followed by two parallel hybridizations with FMDV and SVDV-specific probes in microplate wells and ELISA detection. The application of universal primers could halve the number of PCR experiments in both cases, as compared to the usual virus-specific PCR procedures. Also, we investigated the 3D gene structure of several SVDV strains isolated at different times. No essential changes were detected in the regions coding for conserved motifs of the RNA-dependent RNA polymerase recognized by our universal primers. The multi-primer PCR was successfully tested on 38 FMDV and 15 SVDV strains, and the PCR-ELISA on 32 FMDV and 16 SVDV strains including clinical material from disease cases.
AIMS: This study was carried out to determine the survival time of Escherichia coli, Salmonella choleraesuis, Aujeszky's Disease virus and Blue Eye Disease virus in ensilages based on the solid fraction of pig faeces. METHODS AND RESULTS: The four micro-organisms were inoculated into microsilos based on the solid fraction of pig faeces, sorghum and molasses. They were left for 0, 7, 14, 28 and 56 days, after which the state of each microsilo was evaluated, and isolation of the inoculated agents was attempted. The four inoculated agents were isolated only on day 0 of ensilage. The viral agents were identified through the cytopathic effect and fluorescence. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: It is concluded that ensilages based on the solid fraction of pig faeces appear to reduce the risk of the transmission of the agents inoculated in this study and help to reduce the environmental impact by using the solid in animal feed.
The effect of day-of-age vaccination with infectious bursal disease virus (IBDV) alone or in combination with Marek's disease virus (MDV) in broiler chicks was investigated. One-day-old commercial broiler progeny obtained from IBDV-immunized breeder flocks were vaccinated subcutaneously according to the manufacturer's directions with live-attenuated commercially available vaccines as follows: IBDV alone, MDV alone, IBDV + MDV, and unvaccinated control. IBDV was not detected after vaccination by reverse transcriptase/polymerase chain reaction in any of the bursal, thymic, and splenic tissues tested. Serum IBDV antibody levels, as monitored by enzyme-linked immunosorbent assay (ELISA), showed similar rates of decline among the four groups, and, by day 28 postinoculation, serum antibody levels in all groups were below detectable limits. IBDV-specific neutralizing maternal antibody (MA) titers in the IBDV + MDV and control groups, as monitored by the virus neutralization assay (VN), remained higher and declined more slowly throughout the experiment as compared with VN titers in the IBDV- and the MDV-vaccinated groups. In a second experiment, groups of one-day-old broiler chicks were vaccinated as in Experiment 1. Serum IBDV antibody detected by ELISA and VN assay declined parallel to those observed in Experiment 1. Histopathologic lesions characteristic of IBDV were not observed in any of the groups. Vaccination with MDV alone was associated with increased rates of IBDV neutralizing MA decline similar to those caused by vaccination with IBDV alone, whereas concurrent vaccination with IBDV + MDV was not associated with increased rates of IBDV neutralizing MA decline over that of nonvaccinated controls. Results of these studies indicate that IBDV vaccination at 1 day of age does not cause accelerated IBDV-specific MA decline as detected by ELISA but does appear to cause an accelerated decline in neutralizing IBDV-specific MA. Furthermore, vaccination with IBDV at 1 day of age appeared to slow the accelerated rate of IBDV neutralizing antibody decline caused by MDV vaccination.
Recent studies on bovine virus diarrhoea (BVD virus) afforded a deeper understanding of the epizootiology of this virus. It is of vital importance to determine whether BVD virus infection occurs within the uterus prior to the 120th day of gestation, during a later stage of pregnancy or after birth. When infection occurs before the 120th day of gestation, normal or abnormal calves which persistently carry the BVD virus, will be delivered. When infection occurs during a later stage of gestation, the calves which are born, will be immune to BVD virus. Symptoms of the disease (directly or indirectly associated with BVD virus) may appear in infections at an age under six months. As a rule, effects of BVD virus infection are slight in older animals. The very severe clinical picture of Mucosal Disease is confined to persistently infected carriers of BVD virus. The most important source of BVD virus infection consists in persistently infected carriers of BVD virus, which continue to excrete large quantities of BVD virus. The diagnosis of BVD virus infection is usually established at a late stage during the course of the disease so that vaccination is no longer relevant. Moreover, it is not clear to which extent immunity of gestating animals, induced by BVD virus vaccines, will be able subsequently to protect a foetus from infection due to BVD virus.
The use of the routine method for inactivation of the inductor virus by acidification of interferon to pH 2.0 resulted in a significant decrease in the antiviral activity of pig leukocytic interferon, since the preparation was highly sensitive to changes in the pH values. The use of 0.1 per cent solution of formalin provided complete inactivation of the virus. The antiviral activity of interferon treated with formalin was on an average 5 times higher than that of the preparation incubated at pH 2.5-2.6. Precipitation of pig interferon with polyethylene glycol promoted both increasing of the titers of the antiviral activity of the preparation and elimination of the formalin residues from it. Interferon prepared with this procedure was not toxic in tissue cultures, had no side effects when applied to the eye mucosa and was absolutely harmless when administered to animals. It was shown that inactivation of the inductor virus with formalin was in principle possible in human leukocytic interferon.
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Fisher, Harold W. (University of Rhode Island, Kingston), Hidemi Matsumiya, and Masanobu Azuma. Application of cell fractionation techniques in the study of cells infected with polyoma virus and Newcastle disease virus. J. Bacteriol. 91:1645-1651. 1966.-Techniques which permitted rigorous separation of nuclei and cytoplasm were applied to the study of the formation of Newcastle disease virus (NDV) in an established line of Chinese hamster cells and of polyoma virus (PYV) in mouse embryo fibroblasts. The results obtained for hemagglutinin and plaque-forming titers during virus growth were in agreement with those obtained by others, using different techniques. These indicated that NDV matures in the cytoplasm, and PYV in the nucleus, of host cells.
To develop a herpes virus vaccine that can induce immunity for an extended period, a recombinant Marek's disease (MD) virus (MDV) CVI-988 strain expressing infectious bursal disease virus (IBDV) host-protective antigen VP2 at the US2 site (rMDV) was developed under the control of an SV40 early promoter. Chickens vaccinated with the rMDV showed no clinical signs and no mortality and 55% of the chickens were considered protected histopathologically after challenge with very virulent IBDV (vvIBDV), whereas all of the chickens vaccinated with the conventional IBDV vaccine showed no clinical signs and were protected. Chickens vaccinated with the CVI-988 or chickens in the challenge control showed severe clinical signs and high mortality (70-75%) and none of them were protected. Also, the rMDV conferred full protection to chickens against vvMDV just as the CVI-988 strain did, whereas 90% of the challenge control chickens died of MD. Antibody levels against IBDV and MDV following the vaccination increased continuously for at least 10 weeks. No histopathological lesions in the rMDV-vaccinated chickens and no contact transmission of the rMDV to their penmates were confirmed. These results demonstrate that an effective and safe recombinant herpesvirus-based IBD vaccine could be constructed by expressing the VP2 antigen at the US2 site of the CVI-988 vaccine strain.
Three nonoverlapping segments representing approximately 80% of the 4.8-kilobase pair Aleutian disease virus (ADV-G) duplex genome were molecularly cloned into either bacteriophage M13mp9 (M13bm2 = 0.07 to 0.15 map unit; M13bm1 = 0.15 to 0.54 map unit) or plasmid pUC8 (pBM1 = 0.54 to 0.88 map units). In addition the 0.54- to 0.88-map unit segment of a Danish isolate of ADV (DK ADV) was also cloned into pUC8 (pBM2). The recombinant plasmids pBM1 and pBM2 induced expression of several polypeptides in Escherichia coli JM103 that were specifically recognized by sera from mink infected with ADV. The same three proteins with approximate molecular weights of 55,000, 34,000, and 27,000 were detected both by immune blotting and by immunoprecipitation of [35S]methionine-labeled JM103 (pBM1). None of these proteins were recognized in JM103 or JM103 (pUC8), nor were they detected by sera from normal mink. Purified pBM1 and pBM2 DNA appeared identical in size by gel analysis and contour length measurement, and electron microscopic heteroduplex mapping revealed no visible areas of heterology. However, restriction endonuclease mapping showed that pBM2 was different from pBM1, indicating that this segment of the ADV genome was similar but not identical for two strains of ADV (ADV-G and DK ADV). Furthermore, when cloned DNA from ADV-G was labeled with [32P]dCTP by nick translation, DNA relatedness to several field strains of ADV (Utah I, Pullman, and DK), but not to mink enteritis virus or cellular DNA, was shown by Southern blot hybridization.
Inactivated Newcastle disease virus (NDV) and infectious bursal disease virus (IBDV) were incorporated into water-in-oil emulsion vaccines alone or as a bivalent vaccine. Twenty-week-old broiler breeder chickens that had received previous live virus vaccination with NDV and IBDV were injected intramuscularly with the monovalent or bivalent vaccine. The antibody titers to either the monovalent vaccine or bivalent vaccine increased rapidly and then remained at high levels for the duration of the 40-week trial. There were no practical differences in amplitude or duration of the antibody response to either antigen used alone compared to that of the bivalent combination. Progeny hatched from the vaccinated breeders possessed maternal antibody levels at one day of age comparable to those of the hens at the time the eggs were laid. The maternal antibody titers declined at a steady rate until they reached negligibly detectable levels at approximately 3 weeks of age. This trend held true without regard to the initial antibody titer.
A seroepidemiological study of border disease was conducted in sheep and goats in various areas of Quebec. Sera of 10% of animals of selected flocks were collected and specific antibodies against bovine viral diarrhea- mucosal disease were tested by seroneutralization. Results show that 10.9% and 16% of sheep and goats respectively gave a positive reaction. The lower serological prevalence was found in sheep flocks of the Sherbrooke area (5.4%) while the highest percentage of positive sera was observed in the Quebec area (24.7%). The prevalence in goats varied according to areas (2.6 to 45.5%). No relation was observed in seropositive animals between age, sex, breed and the presence of abortions in the flocks. Our serological results indicate that border disease is probably present in Quebec sheep and goat flocks but that the clinical diagnosis of this disease is not well established.
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