Retrospective epidemiologic diagnosis of viral non-A, non-B hepatitis with a fecal-oral mechanism of transmission of the causative agent

The possibility of the retrospective epidemiological diagnosis of viral hepatitis non A, non B with the fecal-oral mechanism of the transfer of infection in three cities of Central Asia on the basis of the analysis of the dynamics of registered hepatitis A morbidity is shown. With the irregularity of morbidity levels among the total population being characteristic of all three cities, in Andizhan one rise in morbidity within a period of 3 years (1975-1978) and in Tashauz one rise within a period of 5 years (1975-1980) were registered. The analysis of the dynamics of morbidity observed in individual age and social groups showed that these rises, especially those registered in 1976 in Andizhan and in 1977 in Tashauz, were determined by morbidity levels among school children and adults. This is also true for a rise in morbidity rate registered in Tashauz in 1985. In Andizhan the highest morbidity rates among adults were registered in districts insufficiently equipped with modern amenities. Cases of infection registered as hepatitis A (HA) among persons immune to HA at territories with high intensity of the epidemic process of HA at the above-mentioned periods seem to be due to viral hepatitis non A, non B with the fecal-oral mechanism of the transmission of the infective agent.     

Multiyear and seasonal hepatitis A morbidity in different population age groups in certain areas

At the areas with high activity of hepatitis A (HA) epidemic process the duration of epidemic cycles was shown to differ, the intervals between the peaks of morbidity increasing in older age groups. The beginning of seasonal rises exceeding the average annual HA morbidity level in different age groups was found to depend on the activity of the epidemic process. At the areas with the highest activity of the epidemic process children aged 1-2 years were the first to be affected by the seasonal rise of HA. Stable direct correlation between HA morbidity levels at the beginning of seasonal rises and some markers indicative of unfavorable sanitary conditions (the size of the fly population, the purity of water samples deviating from the requirement of the Government Standard) during the preceding year was demonstrated.     

Morbidity and mortality in acute viral hepatitides in a hyperendemic region. The role of viral hepatitis E

Official annual statistical data on morbidity in acute viral hepatitides (AVH), including the number of lethal cases, for 1985-1995 were analyzed. Mortality rates per 100,000 of the population at the period of 11 years were calculated for different age groups, sex and the place of residence. 396 and 99 patients were examined for the presence of serological markers of hepatitides A, B and E, respectively, at the periods of epidemic rises in morbidity and satisfactory epidemic situation. In the course of 11 years AVH caused the death of 22,405 persons. In 1985-1987 the average mortality level (ML) reached 12.3-17.8 per 100,000 of the population (with morbidity being 1,200-1,400 and was essentially higher among the rural population in comparison with the urban population. During these years the highest ML, was registered among children aged 0-2 years (190-50 per 100,000) and, among adults, mainly among women aged 20-29 years (21.4-19.6 per 100,000). During the years when the epidemic of AVH was absent, ML among these groups was essentially lower: 40-20 among children aged 0-2 years and 4-5 among women aged 20-29 years. In 1987 in the Fergana Valley hepatitis E was detected in 72.2% of all examined patients, and in the southern areas of the country in 68.7%. A sharp rise on mortality among women of the productive age at the period of the epidemic rise of AVH morbidity in the endemic region indicated that this epidemic was linked with hepatitis E. High ML among young children may be indicative of a highly unfavorable course of hepatitis E in the group of infants, which had never been registered before. This newly established regularity may be used for the retrospective diagnostics of the outbreak of hepatitis E.     

Monthly dynamics of the epidemic process in viral hepatitis B

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.     

The results of a serological study of viral hepatitis patients and healthy subjects under the conditions of a high-intensity epidemic process in hepatitis A

The activity of the involvement of preschool children of different ages in organized groups into the epidemic process of hepatitis A and the state of population immunity in elderly persons have been studied. Under the conditions of the intensive development of the epidemic process the active involvement of preschool children into this process as early as at the age of 1-2 years has been noted. At periods between epidemics the active circulation of the infective agent in the presence of decreased manifestations of the disease has been revealed.     

Viral hepatitis A and B as a mixed infection in children

Serological examinations of 1,200 children, hospitalized at the viral hepatitis department over a year, for the presence of hepatitis A (HA) and hepatitis B (HB) markers have revealed a 7% incidence rate of mixed HA and HB infections. Three variants of mixed infection have been established (true mixed infection, HA combined with asymptomatic HBsAg carriership, cross superinfection) and the relative significance of each of them has been determined. Mixed infection took an unfavorable course with a tendency to the prolongation of the pathological process eventuating in chronic hepatitis, especially in cases of true mixed infections (15.9%).     

Trace elements in viral hepatitis

In this study, serum trace elements, including selenium (Se), zinc (Zn), copper (Cu), were determined by using Atomic Absorption Spectrophotometer (SpectrAA 250 Plus Zeeman, Varian, Australia) in sera of patients with viral hepatitis (A, B, C, D, E) cases (n = 102), and statistically compared with the controls (n = 52). In viral hepatitis, Cu levels were found as 3.23 ± 1.02 mg/L, and this value was significantly higher than the control group (1.13 ± 0.21) (p < 0.01). Both, Se and Zn levels found to be significantly low in viral hepatitis cases (p < 0.01). While Se level was 81.4 ± 26.01 μg/L in viral hepatitis (n = 101), it was found to be 166.15 ± 4.58 μg/L in healthy individuals. Meanwhile, Zn levels were 0.230 ± 0.081 mg/L and 0.748 ± 0.392 mg/L in hepatitis cases (n = 101) and the control group, respectively. There was no difference amongst viral hepatitis groups classified in regard with agents and clinical manifestation, such as A, acute hepatitis B, chronic hepatitis B, C, D and E. Previously, it was indicated that absorption disorders in gastrointestinal system, especially in chronic cases, were not main causes of decrease of trace elements by iron and several other parameters in sera of the cases. Therefore, we suggest that decrease in Zn and Se levels and elevation in Cu levels are probably resulted from defence strategies of organism and induced by the hormone-like substances.     

Duration of viral RNA circulation in blood of patients with hepatitis A

Duration of hepatitis A virus (HAV) RNA circulation in blood of patients with HA was assessed and compared with intensity of cytolytic syndrome. Detection of viral RNA was performed by RT-PCR method with specific primers to VP1/P2A region of HAV genome. 54 blood serum samples from 40 patients were prospectively studied on the presence of HAV RNA. The latterwas detected in 53.7% of serum samples. The greatest number of positive results of HAV RNA detection in blood of the patients with HA was obtained from 8th to 21st day of illness (77.4%). Prolonged viremia (42+/-9 days) was observed in more than 20% of the patients. The maximal time of HAV RNA daetection in blood serum amounted 74 days (period of follow-up). HAV RNA was present in almost all patients with AIAT activity higher than 500 U/l regardless of duration of illness.     

Seroepidemiological characterization of virus hepatitis in the Republic of Armenia

The survey of the population immunological structure with respect to parenteral hepatitis showed awide circulation of hepatitis B (HB) and hepatitis C (HC) viruses among the adult population of Armenia. During the 5 year period of observation the number of persons having antibodies to HC virus increased 2.7-fold. High occurrence of antibodies to HBsAg of HB virus among the healthy population in 2002 (12.0%) in comparison with 1997 (5.4%) reflected a decreased infection rate with HB virus as well. Antibodies to hepatitis A (HA) virus were isolated, on the average, in 64 % of persons. Simultaneously with a decrease in the proportion of HA cases an increased number of HC patients was registered. No circulation of hepatitis E virus was detected. A high percentage of hepatitis cases of mixed etiology was established, as well as an increased number of combined parenteral hepatitis cases was registered (57.1%).     

Mechanisms of viral hepatitis induced liver injury

Among seven human hepatitis viruses (A to E, G and TT virus), hepatitis B (HBV) and C (HCV) viruses are able to persist in the host for years and principally contribute to the establishment of chronic hepatitis. During the course of persistent infection, continuous intrahepatic inflammation maintains a cycle of liver cell destruction and regeneration that often terminates in hepatocellular carcinoma (HCC). While the expression and retention of viral proteins in hepatocytes may influence the severity and progression of liver disease, the mechanisms of liver injury in viral hepatistis are defined to be due not to the direct cytopathic effects of viruses, but to the host immune response to viral proteins expressed by infected hepatocytes. In the process of liver injury, hepatocellular death (apoptosis) induced by the proapoptotic molecules of T cells activated following antigen recognition triggers a cascade of antigen nonspecific effector systems and causes necroinflammatory disease. Accordingly, the regulation of the immune response, e.g., via the cell death pathways, in chronically infected patients should prevent the development of HCC.     

Methodological bases for the study and the patterns of the seasonality of viral hepatitis 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.     

The territorial and age-related characteristics of the distribution of patients with non-A, non-B viral hepatitis infected via the fecal-oral mechanism in foci of elevated viral hepatitis morbidity in the Uzbek SSR

The study of patients from 10 foci of acute viral hepatitides for the presence of HBsAg (in the passive reverse hemagglutination test) and anti-hepatitis A virus IgM (in the radioimmunoassay) has shown high frequency and variability in the spread of hepatitis non-A, non-B, the prevalence of adults aged 20-29 years and children aged 2-4 years among persons involved into the epidemic process and the tendency towards an increase in the proportion of hepatitis non-A, non-B in the total number of cases of viral hepatitides in the republic.     

A trial of using immunoglobulins of known specificity for preventing hepatitis A in regions with high epidemic activity

The economic effectiveness of immunoglobulin prophylaxis (IGP), carried out among children aged 1-3 at the beginning of a seasonal rise in hepatitis A (HA) morbidity with high coefficients of protection (80-85%), was directly related to the activity of the epidemic process. Preparations with sufficiently high content of antibodies to HA virus sharply decreased the manifestation of this infection. The detection rate of the manifest forms of the infection among children covered by prophylactic measures in the foci of HA was considerably lower than among children who had not received the preparation. IGP exerted no essential influence on the dynamics of the formation of population immunity. A high share of children aged 3-4 years, seropositive to HA virus (up to 90%), validates the inadvisability of carrying out IGP in older groups of children.     

Zonal characteristics of the dynamics of viral hepatitis A morbidity over a period of many years (based on data from the Ukrainian SSR)

The previously established zonal character of the prevalence of viral hepatitis A in the Ukraine is a stable epidemiological regularity observed for more than 30 years (1952-1985). Zonal differences in the dynamics of the epidemic process of viral hepatitis A were established. These differences became particularly hepatitis manifest in the years of periodic rises in the morbidity rate which is also irregular within zonal and regional boundaries. The main typological variants of the dynamics of the epidemic process ("urban" and "rural") were defined. Typological approach appears to be useful in the provision of information necessary for the proper functioning of epidemiological surveillance and for taking measures aimed at epidemics control.     

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.     

Problems of the epidemiology of viral hepatitis in Ryazan Province

The analysis of some features of the course of the epidemic process of viral hepatitis on the territory of the Ryazan region is presented. Periodic rises and falls in viral hepatitis morbidity, varying in their regularity (4-6 years), have been registered in the region. The general level and the seasonal distribution of viral hepatitis morbidity are determined by the morbidity rate among children, the increase in the proportion of children of senior school age being observed in recent years.     

Epidemiology of viral hepatitis: an overview

Nearly all human viral hepatitis is caused by five hepatitis viruses: A, B, C, D (delta) and E. An overview of the epidemiology and current measures for preventing transmission of these viruses are discussed.     

Patients with chronic viral hepatitis as sources of infection

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.     

Characteristics of the manifest and latent components of the hepatitis A epidemic process in cities of Russia

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.     

Vaccinal prophylaxis of hepatitis A in servicemen of the Far East military district

The importance of hepatitis A (HA) for epidemiological situations among the servicemen of the Armed Forces of the Russian Federation, including the Far Eastern Military District, and the necessity of vaccinal prophylaxis have been substantiated. Vaccination against HA, made in a single injection, was shown to be capable of decreasing morbidity, on the average, 1.98 times. The epidemiological effectiveness of vaccine "Avaxim" proved to be 89.6%. The results obtained in this investigation are indicative of the expediency of vaccination not only for prophylactic purposes, but also for localization and liquidation of epidemic foci of HA.