Characteristics of the epidemic process manifested as chronic viral hepatitis

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.     

Epidemiology of viral hepatitis in the Estonian SSR

The epidemiological peculiarities of viral hepatitis in the Estonial SSR as a whole, as well as in Tallinn and in the surrounding Harju region were studied. The study revealed that during the last 10 years the total decrease of morbidity in viral hepatitis was observed due to a decrease in infectious hepatitis, pronounced periodic and seasonal morbidity fluctuations being absent. A sharp decrease in infectious hepatitis morbidity had been achieved by carrying out planned gamma globulin prophylaxis among children. Viral hepatitis morbidity in the republic was determined by the adult population and manifested as sporadic cases of infectious and serum hepatitis. Infectious hepatitis was transmitted mainly through every day contacts, while the leading factor in the transmission of serum hepatitis consisted in various injections. The relatively high morbidity level of serum hepatitis was mainly determined by morbidity in large cities.     

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.     

Spread of hepatitis virus as a threat to national security

Information on viral hepatitis A, B and C morbidity in Russia is presented. A distinct trend to decreased viral hepatitis B and C morbidity in 2001-2002 in comparison with the 1990-ies is noted. Nevertheless, there is still unfavorable prognosis regarding high hepatitis B morbidity among the population of reproductive age, as well as among adolescents, which increases the risk for children at an early age. In addition, a new specific feature of hepatitis A spread is observed: morbidity in this infection is shifted to older age groups. The role of vaccinal prophylaxis in the decrease of hepatitis A and B morbidity, virus safety of blood and its components, the quality of the diagnostics of chronic hepatitis, especially hepatitis C, are discussed. The complex of measures for the prophylaxis of viral hepatitis is proposed.     

Role of carriers of the hepatitis B surface antigen as possible sources of infection in children's collectives

The complex clinico-epidemiological and laboratory surveys of the children and the staff in 71 institutions for children of preschool age were made at the period of increased viral hepatitis morbidity in these institutions, and the dynamic observations of 11 children's institutions having children with prolonged HBs-antigenemia were carried out. In the foci of viral hepatitis the level of antigenemia in the children and the staff exceeded (p less than 0.01) that in the control group. The dynamic observations (lasting up to 6 years) of the groups containing HBsAg-carriers revealed that 6 children, previously HBsAg-negative, showed a short-term HBs-antigenemia in the absence of any evidence of the parenteral (instrumental) route of infection. This fact indicates that the role of HBsAg-carriers as the possible sources contributing to the transfer of hepatitis B through everyday contacts in children's institutions cannot be ruled out. Periodic clinico-epidemiological and laboratory surveys of groups with HBsAg-carriers are recommended.     

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.     

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. The method of Gorky Institute of Epidemiology and Microbiology was used to prognosticate the morbidity. It is recommended to improve the tactics of preseasonal gamma-globulin prophylaxis with consideration to the data of the viral hepatitis prognosis.     

Family incidence of type B hepatitis

Family incidence of HBsAg-positive viral hepatitis was confirmed to be high. In 499 families with a type B viral hepatitis patient, type B viral hepatitis morbidity among 1116 contacts amounted to 2.24% within 6 months of the primary patients' hospitalization (being 188.2 times higher than semiannual morbidity of the population of the Czech Socialist Republic, CSR) and the prevalence of HBsAg amounted to 8.96% (being 22.4 times higher than among the population of CSR). On deducting positive findings at first blood samplings, which at least partially eliminated individuals who could themselves have been the source of infection for the first patient in each family, the rate for contact cases equalled 0.70% (58.8 times higher morbidity than among the population) and the rate for HBsAg prevalence equalled 2.50% (6.25 times higher than among the population). Among 917 members of 335 families where a case of HBsAg-negative viral hepatitis occured, 0.32% developed HBsAg-positive viral hepatitis within 6 months (26.8 times higher morbidity than population morbidity) and the HBsAg prevalence was 2.94% (7.35 greater than among the population). On deducting the first positive findings no clinical illness remained and HBsAg prevalence equalle 0.98% (2.45 times higher than among the population). The highest HBsAg prevalence was found among contacts aged 0-5 years (17.09% for the whole period, 3.41% after deducting first positive findings) and 40 years and over (10.82% and 3.39%, respectively). Type B viral hepatitis morbidity was again highest in the age groups of 0-5 years (5.12%) and 40 years and over (2.54%) for the whole period. On deducting first positive findings, the 40+ years group displayed the highest morbidity (1.27%), whereas the 0-5 years group displayed zero morbidity. Disclosure of the mechanisms of nonparenteral or inapparently parenteral transmission specific for family environments would be important for the prospect of introducing adequate measures to limit or prevent the spread of type B viral hepatitis.     

Nosogeography of viral hepatitis in the Ukraine over the last 25 years (1952-1976)]

For 25 years of observation the morbidity rate of viral hepatitis in the Ukraine was irregular. In individual regions the morbidity level fluctuated within 2 to 3-fold range. Regions with invariably high or low morbidity levels for viral hepatitis were distributed over the territory of the republic not chaotically, but in zones: a zone with invariably high morbidity rate (western), a zone with morbidity rate corresponding to the average level for the republic (south-western), and a zone with an invariably low morbidity rate (north-eastern). The expediency of dividing the territory into epidemiological areas in respect of viral hepatitis on a regional or republican level is discussed.     

Prophylactic efficacy of reaferon in viral hepatitis A and acute respiratory infections in children

Reaferon, the analog of human alpha 2-interferon obtained by gene engineering techniques, was studied with a view to its use for the prevention of hepatitis A. The study involved children of preschool age in Tashkent. In a strictly controlled trial children aged 2-6 years received the preparation orally in a dose of 1 X 10(6) I. U. or the diluent alone used as placebo. The preparation was administered to 1,100 children and the placebo to 1,078 children. The preparation and placebo were administered twice a week for two months. On the whole, during that period hepatitis A morbidity in both test and control groups of children was the same (5.1% and 4.9% respectively), but among children of nursery age receiving Reaferon the incidence of hepatitis A and acute respiratory viral infections was lower than among those receiving the placebo, though this difference was statistically significant only for cases of acute respiratory infections.     

Clinical and epidemiological description of acute intestinal infections in children of the lower Volga region

In accordance with the results of laboratory diagnostics, carried out by bacteriological, serological and PCR methods, the etiological structure of acute bacterial and viral intestinal infections, most frequently occurring in children of the Astrakhan region, is presented. An important role of viral diarrhea cases, prevailing among the total number of cases of intestinal infections in children, is emphasized. The data on the irregular distribution of morbidity by months, especially in viral intestinal infections and salmonellosis with the prevalent involvement of children aged up to 2 years into the epidemic process, are presented. Infections affect mainly children given artificial feeding, as well as those with complicated premorbid state and frequently having acute respiratory viral infections.     

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.     

Spread of viral hepatitis in organized children's collectives and the methods for its early diagnosis]

The authors present the results of observations over 407 children aged from 2 months to 16 years from the foci of viral hepatitis in children's collective bodies. During the quarantine a determination was made in children of the glutamic-pyroracemic, glutamic-oxalic transaminases (GPT and GOT, respectively) and of the hepatitis B antigen (HBAg). A necessity of using the enzymatic tests for the purpose of early diagnosis of viral hepatitis was shown, since 84% of the cases developing in the next focus coursed as an unicteric form without any markked clinical signs; HBAg was revealed in 6.1% of the children examined. A complex examination of the personnel and of the persons who came in contact with the patients with viral hepatitis showed the ways of spread of hepatitis B in a collective body; it was found that the viral hepatitis B infection took place both by parenteral and enteral routes. The expediency of active observation over the children, recipients of blood and plasma, with determination in them of the activity of the enzymes and HBAg for early diagnosis of parenteral infection was substantiated. It was also shown that the incidence of the unicteric forms of viral hepatitis in a focus of infection depended not on the periods of gamma-globulin administration but on the age of children who contracted the infection. Thus, the prevalence of the unicteric forms of the disease over the icteric ones in children under 3 years of age was more pronounced than in older children.     

The determination of hepatitis A antibodies in epidemiological practice

Epidemiological analysis of hepatitis A morbidity in a city with the population of 500,000 persons in 1960-1987 was carried out. Three periods of morbidity rises among children aged 3-6 years and 7-14 years and living at the same areas (microdistricts) were established. Blood sera from healthy children were tested for the presence of antibodies to hepatitis A in enzyme immunoassay. The data on the sanitary and bacteriological study of tap water were analyzed. Unsatisfactory results of water analysis in different microdistricts correlated with the presence of antibodies in the population of these microregions and with the average morbidity indices for many years.     

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.     

Hepatitis A in Estonia (1990-1999)

During recent 10 years (1990-1999) essential changes occurred the epidemiology of viral hepatitis A (VHA) in Estonia: simultaneously with a decreased level of morbidity (morbidity rate per 100,000 of the population was 78.4 in 1990 and 7.7 in 1996, or 1,241 and 112 cases, respectively), a shift in the age structure of patients from children of preschool age to older age groups took place. Everyday contacts were the main established route of VHA transmission in recent years, but in more than 80% of cases the risk factors of the virus transmission remained obscure. During the regional outbreak of VHA in North Estonia in 1998 (937 out of 989 cases registered in the country) a rise in morbidity was observed among young people aged 15-29 years, when a wide spread of parenteral viral hepatitides B and C and drug addiction were registered in this region. During this outbreak VHA was transmitted mainly through everyday contacts. Still the considerable prevalence of injection drug users who practiced the group use of syringes and needles and took drugs from common containers, a sufficiently high level of the mixed forms of the disease (more than 18% of all registered cases of VHA), detected for the first time, make it possible to suggest that the parenteral transmission route could appear among persons belonging to the above mentioned group. Vaccination is regarded as the most effective measure for the prophylaxis of VHA.     

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 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 18.1% at different territories and depended on the total morbidity level, on the season, as well as on the age of patients. A suggestion was made concerning the role of the parenteral mechanism of the transfer of hepatitis non A, non B at the territory under study.     

Prevalence of viral hepatitis among the hospital staff in CSR between 1980 and 1982

The hepatitis morbidity data were used to study prevalence rate of manifest viral hepatitis among the hospital staff members in CSR over a 3-year period between 1980 and 1982. This study showed that the overall hepatitis morbidity rate was 2.68 per 1,000 health personnel and was 3.6 times as high as that recorded in a normal population matched by age. The mean HBsAg positivity rate was 1.67 per 1,000 and was 5.8 times the rate in the control population group. The rate of HBsAg-negative cases of hepatitis was 1.01 per 1,000 health personnel and was higher than double the rate of morbidity encountered in an age-matched normal population. The highest morbidity rates were recorded in the lower-grade and auxiliary health personnel. When compared with an age-matched normal population the hospital staff members at all departments had distinctly higher morbidity rates than the general population, but the highest risk of acquiring viral hepatitis was evidently run by the personnel at departments of renal dialysis, biochemistry, hematology, infectious diseases, internal medicine, surgery, urology and TRD (tuberculosis and respiratory diseases). Of a total number of recorded cases of viral hepatitis those with HBsAg positivity predominated, especially at departments of urology, TRD, internal medicine, renal dialysis, psychiatry and hematology. Analyzed by specialty and professional status of personnel these viral hepatitis morbidity rates encountered among the hospital staff members seem to point to at least two conclusions: this infection in the health personnel is work-related and its transmission and spread is dependent on the frequency and intensity of contact with the blood and other secretions of infectious patients.     

Various epidemiological principles of the spread of viral hepatitis in the Astrakhan district]

Analysis of many-year changes in the vitral hepatitis incidence in the Astrakhan region showed a significant cyclicity of the epidemic process: its incidence rose 4 times during the period of from 1957 to 1976; four of these elevations were comparatively high (in 1960, 1964, and 1974). Lately the group of children aged from 3 to 7 years has been of the greatest epidemiological significance, but at present greatest incidence of the disease fell on the group of persons aged from 8 to 14 years. This can be connected with gamma-globulin vaccinations given to children aged under 10 years. Seasonal distribution of morbidity in different are groups was about the same and reflected the general automn-winter seasonal prevalence.