Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  parwowirus swin typ 2
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
During the last decade a variety of previously unknown porcine parvoviruses (PPV) were identified. New species were classified as PPV2, PPV3, PPV4, bocaviruses or hokoviruses. Preliminary investigations indicate that some of the newly emerging parvoviruses are relatively widespread in the Polish pig population. These findings suggest that the evolution and diversity of parvoviruses is much more complex than previously assumed. Current scientific efforts focus on issues such as the prevalence, pathogenic potential, genetic and antigenic variability, as well as the further evolution of parvoviruses. The aim of the present study was to summarize current knowledge regarding the newly described parvovirus species. First atypical strains of parvoviruses were detected in Asia and classified as PPV2. Latest studies have showed that PPV2 is present in swine in Hungary. In 2008, Lau et al. described animal parvoviruses similar to the human parvovirus PARV4. After the place of their first isolation (Hong Kong), the names “porcine hokovirus” (PHoV) and “bovine hokovirus” (BHoV) were proposed. In 2010, Cheung et al. suggested including PHoV in the Parvovirus genus and changing its name to “PPV3,” but this classification is still unofficial. The presence of PPV3 genotype was confirmed in pigs in Hungary, Great Britain, and Romania, as well as in the population of wild boars in Germany. Another species, PPV4, was found in 2005 in North Carolina (USA). PPV4 has also been detected in China, in both healthy and diseased pigs. In Hungary, PPV4 infection has been confirmed in 13 out of 57 herds analyzed, which suggests a large prevalence of this virus in the swine population. The presence of bocaviruses has been detected in pigs in Sweden, China, and Hungary, as well as in wild boars in Romania. Preliminary results suggest that in the swine population in Poland, not only classical PPV1, but also PPV2, PPV3, and PPV4 are present.
The paper is presenting basic data about circoviruses of swine and subclinical infection or disease they alternatively may cause. PCV1 is mentioned as being non pathogenic. Much more in detail is characterized the PCV2, being at present evaluated as one of the most important pathogenic viruses of swine. The virus is subdivided into genotypes of which PCV2a and PCV2b are the most pathogenic variants. The interaction between PCV2 and its natural hosts, domestic pig and wild boar, is a complex process. Two forms are differentiated: PCV2 – subclinical infection (PCV2-SI) and a disease with clinical symptoms, named nowadays PCV2 – systemic disease (PCV2-SD), replacing the earlier name: postweaning, multisystemic wasting syndrome (PMWS). However there is at present no satisfactory explanation why at the end of the 1990s or beginning of the XXI. century PCV2-SD from a mild and sporadic one changed into a severe epidemic disease. It is at present speculated that some role, contributing to this change may be played by the growing international trade of pigs belonging to susceptible swine genetic lines. The role of vaccination, contributing to selection of pathogenic variants of PCV2 could also be taken into account. An other factor could be co-infections, particularly with PRRSV, PPV and Mycoplasma hyopneumoniae. To some extend changes in management and husbandry could not be excluded. Nevertheless it is necessary to continue research in order to improve knowledge in this area.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 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.