Reported strains of Piscirickettsia salmonis, a pathogen of salmonid fishes, were analyzed by amplifying part of the internal transcribed spacer (ITS) of the nbosomal RNA (rRNA) operon followed by denaturing gradient gel electrophoresis (DGGE) of the amphcons. AU amplified fragments differing in sequence were distinguished by migration during DGGE. A simpler format, constant denaturant gel electrophoresis (CDGE), allowed the same diagnostic distinctions among strains. Sampling during 1997 and 1998 of salmonids from 5 different sites on and near Chilok Island in southern Chile displaying piscirickettsiosis revealed only P. salmonis resembling LF-89, the type strain first isolated in 1989. These observations are encouraging for control strategies, which might otherwise be compromised by unpredictable shifts of P. salmonis types in salmon farms A competitive PCR assay offered insight about the power of PCR for quantification and about specific tissue invasiveness by this intracellular pathogen. This approach revealed that the PCR could amplify approximately 1 to 10 P. salmonis genome equivalents against a background of >99.9% salmonid DNA. It also raised the possibility that the salmonid brain is an important site for P. salmonjs survival, with its bacterial load in 1 individual having been about 100 times the loads observed in liver and kidney. Pathogen detection by competitive PCR in a surface seawater sample from a netpen in use indicated a density of about 3000 to 4000 P salmonis cells (or their DNA remnants) 1-' Such quantitative estimates should aid decisions about disease prevention and management as, for example, choice of netpen sites following fallow periods and certification of ova, which are known conduits of infection.

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The purpose of the study - to study morphological basis of extrahepatic lesions and autoimmune manifestations in chronic viral hepatitises Methods of performance. By indirect immunofluorescence ASMA, AMA, ANA, by enzyme immunoassay - the Anti-LKM-1 were determined. Cryoglobulins (CG) have been revealed with the use of qualitative visualization method, rheumatoid factor (RF) was determined in serum by semiquantitative latex agglutination on a slide. Patients underwent liver biopsy. A punction liver biopsy according to Mengini was performed with the subsequent histologic and morphological research of obtained liver bioptates with the use of an immunohistochemKal and immunocytochemical methods. Results. In patients with chronic viral hepatitis autoimmune manifestations (RF, CG, ASMA, ANA, AMA, anti-LKM-1) were identified at the same rate regardless of the degree of histological activity. In the liver bioptate in patients with chronic viral hepatitises the complex of regulatory T cells (CD4 + CD25 +), which indicates to the presence of morphological and functional basis for the formation of autoimmune manifestations against persistent viral infection was detected. Conclusion. Identified by ourselves autoimmune manifestations in the blood serum be embodied in the morphological changes of the liver tissue, at that the morphological changes characteristic of autoimmune hepatitises, are observed mainly in patients with chronic viral hepatitis B and C, with moderate and high histological activity.

Under investigation of the dynamics of pathogenicity factors H. pylori (LPS/O-antigen markers VacA and high molecular weight proteins (HMWP) (including CagA) in the body ofpatients with acute viral hepatitis (AVH) of different etiology there were established seasonal patterns in feces and serum circulating immune complexes (CIC): LPS/O-antigen markers and H. pylori VacA included in CIC. The detection rate and levels of markers of H. pylori in patients who had AVH in January-April exceeded similar indices in patients whi had AVH in May-August. We believe that these data should be considered in the assessment of the results of the diagnosis ofH. pylori and results of eradication therapy.