[The morbidity and immunological structure of the population in viral hepatitis A at different phases in the development of multiyear epidemic cycles].

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.

[The role of the food transmission factor in the occurrence of 2 hepatitis A outbreaks].

Two outbreaks of virus hepatitis were etiologically and epidemiologically interpreted. In this work the original method of obtaining washings, with their subsequent concentration, from the suspected foodstuff was used and hepatitis A virus was then detected in concentrated washings in the enzyme immunoassay, which made it possible to confirm the contribution of the alimentary factor of the transfer of infection (sun-cured melon) in the above-mentioned outbreaks. The data thus obtained are indicative of the necessity to conduct epidemiological investigation, taking into account the possibility of contacting hepatitis A when using foodstuffs not subjected to preliminary treatment.

[The characteristics of using short-term prediction methods with viral hepatitis morbidity in small areas].

The results of the approbation of the method of using the regressive equation for the short-term prognostication of viral hepatitis morbidity in limited areas (a region or a city). The specific features of the epidemic process, characteristic of limited areas, have been considered. These findings serve as the basis for proposing some methods of prognostication within the limits of an individual region or city, thus making it possible to improve the orientation of prophylactic measures aimed at decreasing viral hepatitis A morbidity.

[The modelling of hepatitis A in macaques].

Characteristics of experimental hepatitis A in Macaca fascicularis and M. mulatta produced with HAV, strain MP, isolated from M. mulatta in an outbreak of spontaneous hepatitis are presented.

[A trial to decrease hepatitis A morbidity in Dzerzhinsk, Gorki Province].

The results of experience in the comparative evaluation of the preseasonal immunoglobulin prophylaxis in two towns of the Gorki Province are presented. The work substantiates the economic and epidemiological effectiveness of immunoglobulin prophylaxis at the territory, relatively safe with respect to hepatitis A, under the conditions of its realization in the year of the predicted rise of morbidity, the timely organization of immunoglobulin prophylaxis (from July to the first half of October) and the coverage of "organized" children, exceeding 90%.

[The epidemiological patterns of hepatitis non-A, non-B].

The etiological structure of viral hepatitides in three cities of the Volga region was studied. The proportion of hepatitis non A, non B was established: it varied from 3.6% to 18.

[Late observations in a familial foci of hepatitis B using a full set of specific markers of the infection].

The complete set of specific markers of hepatitis B has been identified, thus making it possible to evaluate the spread of this infection in family foci, as well as the intensity and dynamics of the epidemic process, under the conditions of prolonged observations. The study has shown that the spread of hepatitis B infection is determined by the presence of HBeAg in antigen-positive patients with viral hepatitis B and HBsAg carriers.

[Etiological structure of viral hepatitis in the area about one of the cities in Gorki Province].

The etiological structure of viral hepatitides (VH) in one of the towns of the Gorky region was studied with the use of specific methods for diagnosing hepatitis A (detection of IgM to hepatitis A virus) and hepatitis B (detection of HBsAg in the passive hemagglutination test). The study revealed that hepatitis A was the major nosological from in the structure of VH among children and adults in the area under survey, which was documented by the detection of IgM to hepatitis A virus. The form, second in importance among VH cases, was hepatitis B.

[Preparation of conjugates for an immunoenzyme method of diagnosing viral hepatitis A].

Evaluation of the activity of peroxidase conjugates with immunoglobulins isolated by different methods from the sera of the subjects with a history of virus hepatitis A, and at various molar ratios of peroxidase and immunoglobulins showed the activity of immunoperoxidase conjugates to depend upon the method of isolation of immunoglobulin used for conjugation. The most active immunoperoxidase conjugates were obtained with immunoglobulins isolated by a column-free method on sephadex DEAE-50A. When peroxidase with a low specific activity is used, the quality of conjugate may be improved by increasing the amount of the enzyme added in conjugation.

[Improvement in the tactics of systematic gamma globulin prevention of viral hepatitis taking the morbidity prognosis into account].

On the example of 4 cites of the RSFSR under conditions of expected epidemic threat a possibility was shown of directed influence on the viral hepatitis A epidemic process of preseasonal gamma-globulin prophylaxis conducted in 90% of "organized" children, aged from 1 to 12 years. The dose used was 0.75 ml of a 10% preparation.