摘要：Three forms of viral hepatitis can be recognized: hepatitis A, hepatitis B, and hepatitis non-A, non-B. Hepatitis A is caused by a picornavirus, is transmitted by the faceal—oral route, does not become chronic, and no chronic virus carriers exist. The virus can be grown in cell cultures, and killed as well as live attenuated virus vaccines are under development. Hepatitis B is caused by an enveloped virus containing a circular, double-stranded form of DNA. The disease is transmitted parenterally through inoculation of blood or blood products containing virus or through close personal contact with a virus-positive person. Hepatitis B becomes chronic in a certain number of cases and can lead to cirrhosis and primary liver cell carcinoma. The blood and certain body secretions of individuals with a persistent or chronic infection may remain infectious for many years. The hepatitis B virus cannot be grown in cell cultures but the entire genome has been sequenced and cloned in bacterial and eukaryotic cells. An inactivated virus vaccine has been prepared from hepatitis B surface antigen present in the plasma of hepatitis B virus carriers and further vaccines are under development. The agents of hepatitis non-A, non-B have not been identified. It is possible to distinguish between a predominantly parenterally transmitted and an orally transmitted form of hepatitis non-A, non-B. The latter is reported to be caused by a picornavirus that does not, however, have any antigenic relationship with hepatitis A virus. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (3.7M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691
