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The purpose of the studies was to determine the rate of rotaviral infection in piglets with the signs of diarrhoea. Samples of faeces were collected from 531 piglets from selected farms, aged 2—8 weeks. The examinations were performed by the ELISA method. The rotaviral antigen was found in piglets from 10 out of 11 farms under study. The frequency of virus occurrence ranged within 6—52% and was highest on large scale farms with the highest number of animals.
The aim of this work was to adapt the Western blot method to analyse the humoral response to proteins of rotavirus strains having various antigens. 10 serum samples from animals immunized with SA11, 18 serum samples from hospitalized children with rotavirus infecitons and 17 serum samples from healthy adults were examined for rotavirus antibodies using Western blot Antibodies against all structural rotavirus proteins were detected. The examined sera reacted differently with rotavirus proteins depending on the strain used. The highest IgG reactivity was observed for Wa and SA11, while the lowest was noted for DS-1. At the same time a different level of cross-reactivity of human sera with specific proteins of antigenically varying rotaviruses was observed. The sera taken from adults showed a lower reactivity with proteins of antigens used compared with sera from children. The exception was VP6 of the Ito strain for which the reactivity of adult sera was statistically higher. Essential differences in the reactivity of children's and adult sera were found mainly in the case of VP2 and VP4 belonging to the SA11 strain and VP4 and VP7 of the Ito strain. From these investigations we can conclude that the Western blot method may be useful in assessing immune response caused by rotaviruses. The results of reactivity of some human sera with proteins of strains used indicates that the persons had previously been infected by antigenically varied rotaviruses.
Rotavirus gastroenteritis has been recognized as the most important cause of acute diarrhea in children between 6 months and two-years-of-age in industrialized countries. Rotaviruses are classified as a genus within Reoviridae family and have a characteristic wheel-like shape. The concentric icosahedral viral capsid, 60-70 nm in diameter, is made up of two protein layers and encloses 11 segments of genomic double-stranded RNA. Each segment of RNA represents one gene that encodes a virus-specific protein. Rotaviruses also contain the spike protein VP4 and a major capsid component, VP7, both of which are responsible for their entry into a cell. Natural infection reduces the incidence and severity of subsequent episodes, rotavirus diarrhea might be controlled through vaccination. Serotype-specific immunity may play a role in protection from the disease.
Występowanie zatruć pokarmowych u ludzi może być związane z obecnością wirusów w środkach spożywczych i wodzie. Żywność zarówno pochodzenia zwierzęcego, jak i roślinnego może zostać zanieczyszczona przez kontakt z osobami chorymi, a także przez skażoną wodę, urządzenia lub opakowania. Najczęściej do zachorowań dochodzi po spożyciu żywności pochodzenia morskiego (ostryg, małż) oraz świeżych produktów (warzyw, owoców). Środki spożywcze mogą być zanieczyszczone norowirusami, rotawirusami lub wirusem zapalenia wątroby typu A oraz wirusem zapalenia wątroby typu E. Wirusy te nie mogą namnażać się w żywności, ale mogą przez długi czas pozostawać w środowisku i wywoływać zatrucia pokarmowe u ludzi. W większości krajów Unii Europejskiej stwierdzono wzrost zachorowań wywołanych spożyciem żywności zanieczyszczonej wirusami.
The aim of this study was to select swine rotavirus strains for the production of a live vaccine against rotaviral porcine diarrhoeas. The estimation of biological properties of strains was carried out under laboratory and field conditions. Seventeen swine field rotavirus strains were used for the investigations. The in vivo experiments were performed on colostrum-free piglets infected per os or intramuscularly with individual rotaviral strains. The virulence of strains was determined on the basis of their clinical condition after infection and the duration of shedder-state for 14 days after infection. In the in vitro estimation of strains, molecular biology methods were used by which extracts of viral RNA were examined by the polyacrylamide gel electrophoresis technique (PAGE). In the in vivo experiments a distinct difference in virulence of particular strains was demonstrated. A correlation between the virulence of particular strains was demonstrated. A correlation between the virulence of rotaviruses for colostrum-free piglets and the presence of rotaviral particles in faeces was found in electron microscopic examinations of faecal samples collected in the from infected sucklings. In some cases no viruses were detected in the faeces of infected piglets. Different electrophoretic mobility of particular genome RNA segments in examined strains was determined by electrophoresis. A rotavirus strain showing lack of virulence for colostrum-free piglets was selected for vaccine production. This strain differed considerably in the distribution of electrophoretic bands from the virulent reference OSU strain of swine rotavirus.
The aim of the study was to test safety, immunogenicity and protective values of an experimental vaccine against rotaviral diarrhoeas in piglets. Laboratory experiments were carried out on 14 pregnant multiparous sows and 212 conventional piglets aged from 1 day to 5 weeks. Field observations were performed on 262 sows and their offspring. In the studies regarding immunogenic properties of the prepared vaccine, the Ambico biopreparation (Dallas Center, USA) was also used as a positive control. In order to assess immunogenic properties of the prepared vaccine two E. coli vaccines i.e. Colivac S-2 and Nobi-Vac Porcoli were included in the field experiments. Laboratory and field safety tests showed that the vaccination of piglets does not cause any disorders in the general health and no local side-reactions were observed in the piglets. Serological examinations revealed high immunogenic properties of the antigen chosen for the vaccine production. Field experiments demonstrated that the administration of the vaccine for prophylaxis of rotaviral porcine diarrhoeas in suckling piglets was very useful.
W próbkach kału dzieci hospitalizowanych z powodu biegunki poszukiwano rotawirusów i chorobotwórczych pałeczek jelitowych. Stwierdzono, że najczęstszą przyczyną biegunki były rotawirusy (46,2%), następnie pałeczki EPEC (10,0%) i pałeczki Salmonella (3,6%). Mieszane zakażenia wirusowo- bakteryjne wykryto u 5,9% chorych.
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