[THE ETIOLOGY OF VIRAL INFECTIONS UNDER TRANSPLANTATION OF KIDNEY AND ALGORITHM OF THEIR LABORATORY DIAGNOSTIC].

The article presents data of virology examination of recipients of kidney in respect of actual agents of viral infections--cytomegalovirus, Epshtein-Barr virus, viruses of human herpes simplex type I and II, virus of human herpes type VI, Varicella-zoster virus, parvovirus B19, adenoviruses and BK virus. The dynamics of development of infectious processes were analyzed for dominating viral infections during 12 months after organ transplantation. The etiologic structure of viral complications in recipients of kidney was identified. The dominating role of cytomegalovirus, Epshtein-Barr virus, BK virus infections (41.9, 30.4 and 17.5% correspondingly) was established. The algorithm of implementation of virology examination of donors and recipients with indication of evaluation of obtained data and recommendations for its application.

Enteroviruses identifications and differentiation on the basis of the selective group--specific inhibitory effect of chemical compounds.

Two new enteroviruses (EV) inhibitors with the selective group-specific effect were detected and studied representing the products of the original chemical synthesis. One of them--nifan (arylfuran derivative) inhibits poliomyelitis virus replication, the other one--belvtazide (synchonic acid derivative) blocks non-poliomyelitis EV (ECHO and Coxsackie B) replication. The study of the reference strains of poliomyelitis virus type 1-3, twenty-three ECHO virus types (from the 1st to the 33rd), Coxsackie B virus type 1-6 and 288 primary EV isolates did not reveal type or strain specific variability in the inhibitors effect. Nifan and belvtazide supress the replication of both EV monostrains and their mixtures. The isolates of mixed nature are inhibited by the mixture nifan + belvtazide. At the same time neither separate chemicals nor their blend affects viruses from other families (Adenoviridae, Orthomyxoviridae, Herpesviridae etc.). The mechanism of nifan and belvtazide action is intracellular EV replication inhibition (they do not affect the process of virus adsorption and penetration into the cell), suppression of de novo virus synthesis by 7.0-2.25 lg (tissue culture infective dose 50 per cent) TCID50/ml and of virus-induced RNA synthesis. The drugs feature is high selectivity (90-91%) regarding RNA polioviruses (nifan) and RNA non-poliomyelitis EV (belvtazide). Nifan and belvtazide antiviral effect selectivity allows unknown cytopathic agents (CPA) belonging to the EV to be established with the high degree (over 98%) of reproducibility at the stage of primary identification with the differentiation of poliomyelitis and non-poliomyelitis viruses.

Viral water contamination as the cause of aseptic meningitis outbreak in Belarus.

In the recent years Echovirus-30 associated outbreaks have taken place in different European countries. Aseptic meningitis caused by Echovirus-30 was the main diagnosis of a large outbreak in Belarus in Summer-Autumn, 1997, involving 460 patients. Echovirus-30 was detected in cerebrospinal fluid of the patients with aseptic meningitis. This serotype played the dominant role in the outbreak. Minor serotypes and mixtures of enteroviruses were detected in faeces and nasopharyngeal lavages. Investigation of environmental samples gave evidence of expressed viral contamination of drinking water and water sources (river and ground sources). River water sources were considerably contaminated with viruses. The incidence of virus isolation was 50%. After cleaning procedures, the incidence became two times lower, proving imperfect water purification and disinfection procedures. Sequence analysis of isolates from Belarus (isolates from water and patient's cerebrospinal fluid) showed the difference of 0.2%. The outbreak peculiarities such as high attack rate and wide-spread of the disease incidences, clinical form variability, isolation of outbreak strain from water and a good agreement between minor serotypes isolated from faeces and water samples as well as correlation in the dynamics of acute intestine infections, aseptic meningitis morbidity and bacterial water contamination can be considered as evidence of its water-borne. Echovirus-30 isolates from Belarus were very closely related to each other and to several European isolates. Sequence difference between isolates of 1994-1998 from European countries was found to be 4.3%. The data can point to the common primary source of enterovirus infection, connected to water and to the possibility of epidemic strain transmission from neighbouring states to the Republic of Belarus.

Virions and intracellular nucleocapsids produced during mixed heterotypic influenza infection of MDCK cells.

Phenotypically mixed virus yields, obtained by coinfection of MDCK cells with influenza A/WSN/33 and B/Lee/40 viruses, contained both A/WSN/33 and B/Lee/40 NP proteins, as revealed by polyacrylamide gel electrophoresis of the purified 14C-amino acids-labeled virus. Virions were lysed with 0.6 M KCl-Triton X-100 buffer, and nucleocapsids were immunoprecipitated with antibodies against NP protein of influenza A virus. Polyacrylamide gel electrophoresis of the immunoprecipitate revealed NP protein of A/WSN/33 but not of B/Lee/40 virus. However, in similar experiments with the lysates of doubly infected cells, the band of B/Lee/40 NP protein was revealed in the polyacrylamide gel electrophoresis patterns of the immunoprecipitates. In an attempt to analyze the RNA content of the immune complexes, we absorbed the lysates of doubly infected [3H]uridine-labeled cells with protein A-containing Staphylococcus aureus covered with antibodies against the NP protein of influenza A virus. RNA extracted from the immune complexes contained genomic RNA segments of both A/WSN/33 and B/Lee/40 viruses. In control samples containing an artificial mixture of cell lysates separately infected with each virus, the analysis revealed homologous components (i.e., A/WSN/33 NP protein or RNA segments) in the immune complexes. The results suggest the presence of phenotypically mixed nucleocapsids in the cells doubly infected with influenza A and B viruses; in the course of the virion formation, the nucleocapsids lacking the heterologous NP protein are selected.

Studies on heterotypic interference between influenza A and B viruses: a differential inhibition of the synthesis of viral proteins and RNAs.

Mixed infection of MDCK cells with influenza A and influenza B viruses leads to a reduction in the rate of synthesis of haemagglutinin (HA) and nucleoprotein (NP) as compared to their rate of synthesis in cells separately infected with these viruses. The reduction is much stronger for influenza A virus proteins. The synthesis of the nonstructural NS1 protein of both viruses is relatively resistant to the heterotypic interference. The synthesis of virus-specific mRNAs exhibits the same pattern: the formation of the transcripts of HA and NP genes is much more drastically reduced than the synthesis of NS gene transcripts. The effect is strongly dependent on the multiplicity of infection and on the ratio of influenza A and B viruses in the inoculum. Primary transcription in the presence of cycloheximide is almost unchanged in doubly infected cells as compared to single infection, and no indication of differential inhibition has been observed. The results are discussed in connection with the mechanism of heterotypic interference and the regulation of influenza virus protein synthesis.