Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 69

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
13
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Chlamydiosis of the air sacs in geese

63%
The course of chlamydiosis of the air sacs in geese was described. The results of clinical, pathological and microbiological investigations confirmed the incidence of this disease in the examined birds.
Although the “stamping-out” policy in combination with movement and trade restrictions of poultry and poultry products are the major methods of avian influenza (AI) eradication, especially its highly pathogenic form (HPAI), vaccination can be considered as a valuable tool in AI control. The international regulations allow for the implementation of vaccination policies with strict provisions. One of the major components of the vaccination program should be “DIVA” (“Detecting Infected from Vaccinated Animals”) strategy. DIVA is a concept allowing the detection of infection in a vaccinated population of animals. It consists of the application of sentinel birds, vaccines and DIVA companion serological tests differentiating post-infection from post-vaccination antibodies. At present, inactivated vaccines are most commonly used, but other vaccines such as recombinant vector or DNA vaccines have also been licensed and utilized. Vaccination against HPAI H5N1 has been used most extensively in Asia, especially in the People’s Republic of China, and to some extent in other parts of the world, including Europe. Countries which have the experience of poultry vaccination to combat AI caused by subtypes other than H5N1 include: Italy (H7N1, H7N3), Mexico (H5N2), USA (numerous subtypes).
The paper reviews molecular markers and determinants associated with virulence, host adaptation and drug resistance in avian influenza viruses (AIV). The virulence of AIV is mostly dependant on the presence of multiple amino acids (mainly arginine and lysine) at the cleavage site of the haemagglutinin (HA) protein. The major factors contributing to host adaptation are also harbored within the HA protein: amino acids at positions 226 and 228 determine virus binding affinity to receptors present in cell membranes of birds or humans. It has been shown that pathogenicity and host adaptation are also dependant on the amino acid sequences of the polymerase complex (PB2-PB1-PA) and the most significant mutation (E627K in PB2) is related to the increased replication of the virus in mammalian cells. Molecular markers associated with an increased resistance to antiviral drugs are localized in neuraminidase (NA) and matrix (M) proteins. For example, a histidine to tyrosine substitution at position 274 of NA (H274Y) decreases viral susceptibility to neuraminidase inhibitors (e.g. oseltamivir), the most frequently used drugs in flu treatment. Monitoring of the molecular changes in the viral genome of AIV is very important from an epidemiological point of view and can be a valuable part of an early warning system.
Three hybridoma cell lines (AC2, DC6, PC2) secreting monoclonal antibodies (MCA) against protein 27, a major component of group specific antigens of avian leucosis viruses, have been employed. All three monoclonal antibodies reacted with p27. The epitope topological studies demonstrated that MCA, DC6 and PC2 were directed to different epitopes of ALV-p27. Comparative studies of different MCA sets for the detection of ALV gs-antigens with the ELISA test demonstrated that the sensitivity of the test, using MCA PC2 for adsorption and a HRP as a conjugate, was the same as one in the commercial kit and was higher when compared with another commercial DAS ELISA kit.
20
63%
In this study, a pigeon paramyxovirus type 1 (PPMV-1) isolated from a flock of ornamental pigeons in Poland in 2010 is described. The PPMV-1/Poland/H2/10 isolate showed the amino acid sequence at the cleavage site of F2/F1 ¹¹²KRQKRF¹¹⁷ i.e. typical of virulent strains. Despite having the monoclonal antibody binding pattern typical of pigeon variants PPMV-1 (antigenic group “P”), the Polish isolate clustered into genetic sublineage 4a, which is usually associated with PMV-1 isolated from poultry.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.