Reasons for the decrease in viral hepatitis morbidity in Orekhovo-Zueve]

Factors of action on the epidemic process in viral hepatitis in Orekhovo-Zuevo leading to a sharp reduction of the incidence of this disease (which before failed to differ from the mean level in the USSR) -- from 154.0 per 100 thousand residents in 1970 to 36.5 per 100 thousand residents in 1975 are considered from the point of view of discussion of the work of Gromashevsky and Birinboim (ZMEI No. 11, 1976). The decisive significance of measures directed to reduction of the incidence of intestinal infections and gamma-globulin vaccinations is refuted. There was revealed a direct 100% correlation between the incidence of positive benzidine tests for blood contamination of medical instruments and the changes in the viral hepatitis morbidity. Planned measures directed to the elimination of factors of parenteral transmission of the infection carried out intensively from 1970 led to reduction of the incidence of viral hepatitis.     

Epidemiological analysis of hepatitis A morbidity

A retrospective epidemiological analysis of hepatitis A morbidity for many years among the population of two neighboring towns in the temperate climatic zone of the USSR has revealed the cyclic character of the epidemic process without a perceptible decrease in its extensiveness and has determined the high-risk groups, as well as the beginning of the seasonal rise of morbidity in these groups. The results of the study indicate that different levels of hepatitis A morbidity and risk groups can be observed in these two neighboring towns. At periods of a lower morbidity level the high-risk group embraces schoolchildren, and when morbidity is at a higher level the risk group includes schoolchildren and preschool children in organized groups. Among the latter the morbidity level is influenced by factors acting all the year round and among school children, by seasonal factors. The beginning of the seasonal rise of morbidity falls on August, while in organized groups of children of preschool age the seasonal rise of hepatitis A morbidity begins 1-1.5 months later. All prophylactic measures for controlling hepatitis A should be carried out with due regard to these features of the epidemic process.     

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.     

Patterns of the epidemic process in viral hepatitis A and B in territories with different morbidity levels. I. Hepatitis A

On the basis of data obtained by seroepidemiological studies general regularities, as well as essential differences, in the manifestations of the epidemic processes characterized by the active and sluggish spread of infection induced by hepatitis A virus have been revealed.     

The epidemiological differential diagnostic signs of viral hepatitis A and viral hepatitis E]

A retrospective epidemiologic analysis of cases diagnosed as hepatitis A (HA) has been made in territories characterized by high intensity (4 towns in Central Asia) and low intensity (Novomoskovsk, Tula Province) of the epidemic process development. Morbidity structures for different age and social groups of the population, as well as the morbidity time course, both annual and over many years, were analyzed over 1973-1986. Specific features in the development of the epidemic process in HA and hepatitis E (HE), formerly called hepatitis non-A, non-B with the fecal/oral mechanism of the infection transmission, were studied. Twelve epidemiological differential diagnostic signs of these two infections were formulated, classified, and validated. Contribution of centralized water supply and sewage systems to the development of HE epidemic process and the regulating role of infectious immunological mechanisms in the development of HA epidemic process were demonstrated.     

Spatiotemporal dynamics of viral hepatitis A in Italy

Viral hepatitis A is still common in Italy, especially in Southern regions. In this study, a metapopulation model for hepatitis A virus (HAV) transmission is proposed and analyzed. Analytical results on the asymptotic and transient behaviors of the system are carried out. Based on the available Italian movement data, a national spatial contact matrix at the regional level, which could be used for new studies on the transmission dynamics of other infectious diseases, is derived for modeling fluxes of individuals. Despite the small number of fitted parameters, model simulations are in good agreement with the observed average HAV incidence in all regions. Our results suggest that the mass vaccination program introduced in one Italian region only (Puglia, the one with the highest endemicity level) could have played a role in the decline of HAV incidence in the country as a whole. The only notable exception is represented by Campania, a Southern region showing a high endemicity level, which is not substantially affected by HAV dynamics in Puglia. Finally, our results highlight that the continuation of the vaccination campaign in Puglia would have a relevant impact in decreasing long-term HAV prevalence, especially in Southern Italy.     

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%.     

Dynamics of typhoid-paratyphoid infection morbidity in Chimkent Province

The study of the time course of typhoid-paratyphoid infections in the Chimkent region for the period of 1944-1979 has revealed the periodicity of their rises (falls) repeating every 2-4 years. Since 1964 the tendency towards the decrease of morbidity has been observed. The annual rate of this decrease is 4.9%. Periodic changes in the annual level of typhoid-paratyphoid infections do not depend on the temperature of the air and the seasonal number of winged flies. There is a pronounced direct correlation between the annual morbidity level and the frequency of summer precipitations, this correlation being more pronounced during the first 2 summer months.     

Pathogenesis of viral hepatitis

The aim of our research is to use animal models to elucidate the molecular basis for viral clearance and liver disease in the pathogenesis of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. The results herein discussed provide insight into immunological and virological processes that may lead to the development of new therapeutic strategies to terminate chronic HBV and HCV infections.