[Specific clinical, epidemiological patterns and laboratory diagnostics of enterovirus infection in the Republic of Belarus].

The clinical and epidemiological patterns as well as the results of the laboratory verification of the outbreak of enterovirus infection (EVI) in Minsk during the period of summer-autumn, 2000, are presented. During this outbreak a variety of clinical forms were observed, the serous meningitis being prevalent (57.5%). Practically simultaneous occurrence of infection on the territory of all administrative districts of the city, the predominant involvement of children aged up to 14 years into the outbreak, a high proportion of simultaneous casualities in the multiple foci. A number of circulating enteroviruses (EV)--ECHO 30, ECHO 6 of three serotypes and Coxsackie B5--were simultaneously isolated from clinical material. EV of the same serotypes were isolated from tap drinking water, and neutralizing antibodies to these serotypes were often detected in the patients blood sera. Infectious EV were also present in samples of bottled water and in water reservoirs used for bathing. The routes of EV transmission and the improvement of EVI control are discussed.

[Laboratory diagnostics of enterovirus cardiac infections]. / Laboratornaia diagnostika énterovirusnykh infektsii serdtsa.

Diagnostic efficacy of different markers of enterovirus cardiac infection (EVCI) has been evaluated. Testing of clinical samples from patients with myocarditis (n=50), dilatation cardiomyopathy (n=122), ischemic heart disease (n=34) and from healthy donors (n=50) revealed diagnostically significant markers in patients suspected for enterovirus cardiac infection: antienterovirus IgM in the patient's blood serum, the expression of viral proteins by myocardium cells and the presence of genome RNA and replicative intermediate in cardiac cells. The results obtained were used for developing up-to-date scheme of the EVCI diagnosis which included the data from the case history, the preliminary rapid diagnosis and the molecular biological study of the cardiac biopsies.

[Outbreak of enteroviral infection in Vitebsk during pollution of water supply by enteroviruses]. / Vspyshka énterovirusnoi infektsii v Vitebske v usloviiakh zagriazneniia pitevoi fody énterovirusami.

The conducted virologic, serological and molecular-and-biological investigations showed that virus Coxsakie B4, isolated from cerebrospinal fluid and rhinopharyngeal lavages of patients, was the main etiological agent, which caused mainly an outbreak of enterovirus infection in the city of Vitebsk in 2001. Coxsakie B4 viruses were found in 30% of samples by using the cultural method and in 76.9% of samples--by polymerase chain reaction (PCR) while carrying out the sanitary-and-virologic investigations in drinking water, including in infection foci. Besides, we found infectious non-cytolitic enteroviruses (EV) with changed biological properties (which could not be detected by the classic cultural method) in drinking water by using the method of PCR integrated with cell culture in the "-" strand of EV RNA. Peculiar clinical-and-epidemiological characteristics of the disease outbreak, i.e. "explosive" onset, multiple clinical forms, mixed EV infections and disease decay after drinking-water chlorination, as well as the isolation of one and the same EV serotype from patients and from water testify to a possible water origin of the outbreak.

[Experience in the use of chemical compounds for the primary identification and differentiation of enteroviruses]. / Opyt ispol'zovaniia khimicheskikh soedinenii dlia pervichnoi identifikatsii i differentsiatsii énterovirusov.

Data on the usage of chemical inhibitors nifan and belvtazid, which possess a selective and antienteroviral effect, in the primary identification of enteroviruses and their differentiation into polio- and non-poliomyelytic ones isolated from human clinical materials or the environment by using the cell culture are presented in the article. The method is recommended for the practical use by the virology service in the diagnostics of enteroviral infections and in the identification of cytopathic agents isolated from the enviroment.

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.

[Changes in phospholipid components of pulmonary surfactant in experimental influenza infection and their correction by remantadin and deitiforine]. / Izmeneniia fosfolipidnykh komponentov surfaktanta legkikh pri éksperimental'noi grippoznoi infektsii i ikh korrektsia remantadinom i deitiforinom.

Changes in the levels of total phospholipids and phospholipid fractions of pulmonary surfactant fractions of albino mice intranasally infected with influenza A/Aichi/2/68(H3N2) virus in a dose of 5 LD50 were studied. Reproduction of influenza virus in mice is paralleled by fluctuations in the level of total lipids and changes in the phospholipid components of pulmonary surfactant. Antiviral drugs remantadin and deitiforine injected in accordance with the treatment and prophylaxis protocol to infected animals exerted a protective effect as regards the studied pulmonary surfactant phospholipids.

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.

[Water-borne outbreak of serous meningitis caused by Echovirus-30 in Belarus]. / Vodnaia vspyshka seroznogo meningita, vyzvannaia virosom Echo-30, v Belarus.

In recent years outbreak of enterovirus infections caused by Echovirus-30 were rather frequently registered in different European countries. A major outbreak caused by this virus took place during the summer-autumn period of 1997 in the city of Gomel, Belarus. Sanitary epidemiological and molecular epidemiological studies made it possible to determine that the outbreak was water-borne. The sequence analysis of Echovirus-30 strains isolated from water and the cerebrospinal fluid of patients revealed a minor divergence between them (0.2%) indicative of their practical identity. The comparison of the Belorussian isolates with the strains isolated in Europe in 1994-1998 also showed a small percentage of differences in their genomes, which showed that the outbreak of Echovirus-30 infection was probably brought to Belarus from the territories of European countries.