[Use of highly sensitive methods of detecting hepatitis B virus markers for studying epidemic foci of hepatitis B]. / Ispol'zovanie vysokochuvstvitel'nykh metodov obnaruzheniia markerov virusa gepatita B dlia izucheniia épidemicheskikh ochagov étoi infektsii.

Passive hemagglutination test (PHA) was found to detect HBsAg in the population living outside the hepatitis B virus foci 1.5-fold as frequently as counter immunoelectroosmophoresis technique, and anti-HBs by enzyme immunoassay 14-fold as frequently. As compared with normal population, the contacts in foci had 4-fold higher levels of HBsAg carrier state and twice as high rates of detection of anti-HBs. The total index of HBV infection in foci was 27.7%. The above materials considerably extend the concepts of HBV epidemiology. The regularity of the results obtained indicate the specificity and high sensitivity of PHA and EIA tests and suggests that they be used on a wider scale.

[Viral infection markers in foci of chronic hepatitis B]. / Markery virusnoi infektsii v ochagakh khronicheskogo gepatita B.

The intensity of detection and time course of the main markers of virus infection were studied in subjects who had contacts with patients in 74 foci with chronic active hepatitis, 52 with chronic persisting hepatitis and 41 with chronic hepatitis of unknown etiology. A high (up to 80.7%) frequency of detection of HBsAg, anti-HBs, anti-HBc was established in contact subjects which showed a trend of growth with the increase of the time of their contact with the source of infection.

[Experience in the detection of the latent course of the epidemic process of viral hepatitis in children in preschool groups]. / Opyt vyiavleniia skryto protekaiushchego épidemicheskogo protsessa virusnogo gepatita v detskikh doshkol'nykh kollektivakh

A complex study of 1273 healthy children of creches and kindergartens where no viral hepatitis occurred for a long time revealed 39 children (3.1%) with an increased activity of glutamine-pyroracemic transaminase in the blood serum. Viral hepatitis was diagnosed in 12 (0.94%) of them as a result of clinical examination (an icteric form in 1, and a nonicteric form in 11 cases). The presence of asymptomatic form of infection could be supposed in 17 other children (1.3%). The incidence of increased activity of the enzyme in the serum of "healthy" children was definitly connected with the viral hepatitis incidence registered in the town during the year as a whole, and by seasons. This permitted to prognosticate the spread of viral hepatitis in the given populated locality. By complex laboratory examination of children in collective bodies it was possible to detect the latene foci and the latently coursing epidemic process of viral hepatitis.

[Methodological bases for the study and the patterns of the seasonality of viral hepatitis A]. / Metodicheskie osnovy izucheniia i zakonomernosti sezonnosti virusnogo gepatita A.

On the basis of the study of the data on the incidence of viral hepatitis A in one of the districts of a big city for 20 years the authors come to the conclusion on the advisability of a comparative study of the monthly changes in the incidence of hepatitis A within individual uniform morbidity cycles covering the periods of many years and the use of average monthly data for many years for plotting the typical curve, as well as the use of the simplified for the calculation of the upper limit of annual morbidity. Similarities and differences in the monthly dynamics of morbidity in the years of high and low morbidity levels have been revealed, and the age group of the population (20-39 years) which ensures the continuity of the epidemic process all the year round has been determined. The factors contributing to the seasonal activation of the epidemic process start operating in June among schoolchildren aged 11-14 years, and later their operation spreads to other groups of the population.

[Patients with chronic viral hepatitis as sources of infection]. / Bol'nye khronicheskim virusnym gepatitom kak istochniki infektsii.

Dynamic observation on 126 foci of infection formed by patients with manifest forms of chronic hepatitis B, 41 foci of chronic hepatitis of unknown etiology, and 37 foci formed by chronic "healthy" carriers was made. In the foci of type 1 the epidemic process developed intensively and was manifested mainly by HBsAg carriership in persons having had contacts with the patients. During the period of observation 43.0% of new cases of infection were detected. In the foci of types 2 and 3 the frequency of contacting infection was not different from that in the control group of the population.

[The theoretical bases of the epidemiology of viral hepatitis B]. / Teoreticheskie osnovy épidemiologii virusnogo gepatita B.

In this article the development of the concepts concerning the sources of hepatitis B virus in the second half of the XXth century is analyzed and the importance of patients with manifest and latent forms of chronic infection as the main reservoir of the infective agent is substantiated. The scheme of the mechanisms and paths of the transmission of hepatitis B virus is proposed, the mechanism of transmission understood only as the natural ways of the spread of the infective agent which result from its evolutionary development and can be only slightly controlled at present. The study revealed that the present decrease of morbidity rate is greatly determined by measures of the social character, aimed at the elimination of the artificial paths of virus transmission.

[Characteristics of the epidemic process manifested as chronic viral hepatitis]. / Osobennosti épidemicheskogo protsessa, proiavliaiushchegosia khronicheskim virusnym gepatitom.

The incidence rates of chronic viral hepatitis in Leningrad over the period of 1962-1984 were studied. The tendency towards a rise in total morbidity because of increased incidence of chronic hepatitis B was shown to appear in recent years. This increase in morbidity was mainly due to its rise among adult males and children, which led to the shift of morbidity to younger age groups. The seasonal rises of morbidity in winter and spring were found to be characteristic of viral hepatitis.

[Monthly dynamics of the epidemic process in viral hepatitis B]. / Pomesiachnaia dinamika épidemicheskogo protsessa pri virusnom gepatite.

Monthly fluctuations in the number of registered cases of acute viral hepatitis B and HBsAg carriership have been studied. The study has revealed that, similarly to other infectious diseases, viral hepatitis is characterized by monthly fluctuations in the intensity of the epidemic process. Such fluctuations are characteristic of all known clinical forms of this infection; they are determined by the specific pathogenetic features of the process and by the ways of the transfer of the virus. The vernal rise of the infection is explained by activation of the manifest and asymptomatic chronic variants of the infectious process and, as the consequence of a rise in the number of asymptomatic cases, by a higher incidence rate of post-transfusion hepatitis infection. The autumnal rise of the infection results from the action of natural factors contributing to the transfer of the virus. Both rises are interrelated and interdependent. The seasonal fluctuations of the epidemic process should be taken into consideration when planning and implementing prophylactic and epidemic-control measures.

[Epidemiological characteristics and the importance of carriers of the surface antigen of the hepatitis B virus (HBsAg)]. / Epidemiologicheskaia kharakteristika i znachenie nositelei poverkhnostnogo antigena virusa gepatita B (HBsAg).

The occurrence of HBsAg carriership in Leningrad has been found to be 1.4% according to the results of countercurrent immunoelectroosmophoresis (CIEO) and 2.1% according to the results of the passive hemagglutination (PHA) test. In children HBsAg occurs with higher frequency: 1.9% according to the results of CIEO and 3.4% according to the results of the PHA test. The latter test reveals HBsAg carriers more completely, especially in women who have usually less pronounced antigenemia than men. Most of chronic HBsAg carriers are patients with chronic forms of hepatitis B (chronic active hepatitis and chronic persistent hepatitis); frequently they become the source of infection among their relatives under the conditions of family contacts. A complex of antiepidemic measures is necessary in the foci of chronic HBsAg carriership.

[An epidemiological assessment of the chronic carriage of the hepatitis B virus surface antigen and other markers of this infection]. / Epidemiologicheskaia otsenka khronicheskogo nositel'stva poverkhnostnogo antigena virusa gepatita B i drugikh markerov étoi infektsii.

On the basis of prolonged (up to 10 years) observations of chronic HBsAg carriers (87 persons) slowly progressing chronic hepatitis B virus infection was detected in most of them (57.5%). In these persons up to 6 negative results of the analysis for the presence of HBsAg were periodically obtained, with the subsequent renewal of HBs-antigenemia. More profound examination of 192 persons with chronic lesions of the liver and other digestive organs helped diagnose chronic persistent hepatitis and chronic active hepatitis, accompanied by HBs-antigenemia and the circulation of other markers of this infection, in 63.5% of the examinees.

[Characteristics of the manifest and latent components of the hepatitis A epidemic process in cities of Russia]. / Kharakteristika manifestnogo i skrytogo komponentov épidemicheskogo protsessa gepatita A v gorodakh Rossii.

Seroepidemiological study of hepatitis A (HA) morbidity was carried out in three Russian cities, with different levels of HA morbidity. The study included the analysis of HA morbidity for 22 years, the determination of antibodies to HA virus (anti-HAV) in 2,958 healthy persons aged 0-12 months to 40 years and older. In one of the cities 7 isolates of HA virus were obtained from unrelated sources and the genotypes of the virus were determined. The study revealed that the frequency of seropositive cases among persons of different ages correlated with the level and prolonged dynamics of HA morbidity. According to the occurrence of anti-HAV, such cities as St. Petersburg, Rostov-on-Don and Yakutsk may be at present classified as territories, moderately endemic in HA. At the same time in the 90 s the epidemic situation in HA was more favorable in Rostov-on-Don than in two other cities. The suggestion was made that a high proportion of seropositive persons among the population of St. Perersburg was linked with an almost twofold rise in HA morbidity in 1993-1995 caused by genotype 1 of the virus. Seroepidemiological studies in HA during the period of a drop in morbidity acquire special importance in the surveillance and control system of this infection.

[The morbidity and immunological structure of the population in viral hepatitis A at different phases in the development of multiyear epidemic cycles]. / Zabolevaemost' i immunologicheskaia struktura naseleniia pri virusnom gepatite A v raznye fazy razvitiia mnogoletnikh épidemicheskikh tsiklov.

For the first time population immunity to virus hepatitis A has been studied during three different phases of prolonged morbidity cycles of this infection, and the results of this study have been compared with the data on morbidity in different age groups. Pronounced variability of the immunological structure of the population in different age groups, found to be related to the dynamics of hepatitis A morbidity, has been established. Fluctuations in immunity level are most pronounced among children aged 1-6 and 7-14 years, having the least proportion of seropositive persons. A new epidemic cycle is started among these groups of the population, and at the first stage this cycle is manifested by an increase in the intensity of the latently developing epidemic process. This is followed by the activation of registered morbidity among the whole of the population. Seroepidemiological study may be used both for prognostication purposes and in the system of surveillance on this infection.

[Epidemiologic indices of cervical cancer morbidity in areas with various levels of industrial pollution]. / Epidemiologicheskie osobennosti raka sheiki matki na territoriiakh s razlichnymi urovniami tekhnogennogo zagriaznenia.

While general cervical carcinoma morbidity is on the decline in most of the surveyed Russian Federation areas characterized by varying levels of industrial pollution, the heavily industrialized region of Salavat revealed a different tendency. Its level was 1.6 times (p<0.05) those in other areas. That was due to the morbidity of women aged 40-69 and even 20-29 and 30-39 years.