The epidemiological aspects of viral hepatitides in Estonia]

The etiological structure of viral hepatitides among the adult population of Tallinn and the occurrence of markers of hepatitis B and hepatitis C virus infections in medical workers, addict introducing drugs intravenously and hemodialysis patients were studied. Changes in the etiological structure of viral hepatitides were established: they took the form of a decrease in the level of hepatitis A morbidity and the considerable growth of the role of hepatitides B and C, as well as the newly detected circulation hepatitis D virus. About one-third in the structure of morbidity in viral hepatitides were hepatitis cases without markers of hepatitis A, B or C viruses (non-A, non-B, non-C). The highest rates of hepatitis B virus infection (78.9%) and hepatitis C virus infection (82.5%) were detected among drug addicts. Their level of HBsAg was 8.8%. In the group of medical workers, 25% of the examinees, i.e. every fourth person, had markers of hepatitis B virus, while antibodies to hepatitis C virus were detected in 5% of cases. Among hemodialysis patients these rates were 21.4% and 10.7% respectively.     

Vaccination of medical personnel against hepatitis B: epidemiological and socio-economic aspects

Epidemiological and social aspects of the vaccinal prophylaxis of medical personnel against hepatitis B are discussed on the basis of the morbidity analysis in viral hepatitis, the results of dynamic screening for the presence of hepatitis B markers and the state of postvaccination immunity. The reactogenicity and immunogenicity of the vaccine "Euvax B", as well as the socio-economic effect of vaccinal prophylaxis, are evaluated.     

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.     

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.     

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.     

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.     

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.     

Condition of morbidity of viral hepatitis and ways of improving prevention of these infections among the populace of the USSR

In this article the state of morbidity in hepatitis A and B in the USSR as a whole and in individual republics is analyzed, the causes of the preservation of high morbidity levels in some regions of the USSR are shown, the specific epidemiological features of fecal-oral hepatitis non A, non B in the republics of Central Asia are pointed out and the ways for improving separately the prophylaxis of hepatitis A and hepatitis B are considered.     

HIV infection and parenteral virus hepatitis in the Krasnodar territory

The analysis of the morbidity dynamics of HIV infection, hepatitis B and C in the Krasnodar territory for 1996-2003 is presented. The tendency of strengthening direct correlation between age-dependent rates in these groups of diseases has been established. The correlation coefficient (rxy) is at present +0.851 (HIV infection-virus hepatitis B) and +0.892 (HIV infection-virus hepatitis C). The highest levels of primary morbidity are registered in persons aged 20-39 years. The established epidemiological parallels between HIV infection and parenteral hepatitis require the development of the unified strategy of the prophylaxis of these diseases on the federal and regional levels.     

消化道传播病毒性肝炎研究进展

病毒性肝炎是由多种不同肝炎病毒引起的,以肝脏损害为主要表现,具有广泛流行性和严重传染性的一类疾病,严重危害人类健康,是我国目前重大的公共卫生问题之一。迄今鉴定出的具有明确致病性的肝炎病毒主要是甲型肝炎病毒(HAV)、乙型肝炎病毒(HBV)、丙型肝炎病毒(HCV)、丁型肝炎病毒(HDV)和戊型肝炎病毒(HEV),分别引起甲、乙、丙、丁、戊型肝炎。病毒性肝炎按传播途径的不同可以分为两类,一类是经肠道外传播的病毒性肝炎,包括乙、丙、丁型肝炎;另一类是经肠道(即消化道)传播的肝炎病毒,包括甲肝和戊肝,其发病有季节性,可呈暴发流行。本文旨在对经消化道传播的病毒型肝炎(甲肝、戊肝)的病原学、流行病学特征及其影响因素、控制和预防作一综述,以期对其流行和科学防控研究提供参考。     

Viral hepatitis markers in antepartum and postpartum women in Rio de Janeiro,Brazil

A seroprevalence study was carried out among a group of women in Rio de Janeiro to determine the prevalence of different markers for viral hepatitis given the limited data among healthy populations. Blood samples collected and tested from 874 women before or after delivery in a public county maternity hospital demonstrated age to be directly related to markers for hepatitis A virus and hepatitis B virus (HBV) infection. The prevalence of HBV and hepatitis C virus infection were lower than that observed in the blood donor population and might be explained by the younger age group and gender.     

Sewage workers: risk of acquiring enteric virus infections including hepatitis A

To determine if sewage workers have an increased risk of acquiring viral infections, 66 workers at a small wastewater plant in north-eastern Italy and 72 control subjects recruited from blood donors were enrolled in a seroprevalence study to determine whether sewage workers are at increased risk of acquiring viral infections. In order to evaluate various risk factors, a questionnaire was filled out by each worker whereas seropositivity to Hepatitis A virus, Coxsackievirus B2 - B3 - B4 - B5, and Echovirus types 1 and 9 was determined in the laboratory. Anti-HAV antibodies were present in 37.8% of sewage workers and 36.1% of subjects in the control group. The difference was not statistically significant in the two groups, whereas a significant association was observed regarding age (P < 0.3). No association was observed with the occupational age, or with number and duration of contacts per day. The lack of evident occupational risk for hepatitis A among sewage workers may be explained by the adult age of the workers (mean age 41.3 years, range 22-58 years), and thus the antibody titre against different enteroviruses was determined. No statistically significant differences were evident with the raw values, but considering the 90 degrees percentile as a dichotomic value for the antibody levels a strong and significant association was present with Coxsackievirus B3 (O.R. 22.85, C.I. 95% 2.93-178.08) and Coxsackievirus B2 (O.R. 14.25, C.I. 95% 1.78-113.87). Analysis of the data confirms a limited risk of acquiring infection and/or disease but also the evident possibility of silent exposure to the viruses. The shift in HAV epidemiology and increased morbidity and mortality in adult age suggest that active immunization against hepatitis A should be considered.     

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.     

Current Concepts of Viral Hepatitis and A Peek into the Future

New information has prompted revision of the conceptual framework for considering the epidemiology and virology of viral hepatitis. The means are now at hand to identify infections due to either Hepatitis A or B, as well as to implicate other etiologic agents in hepatitis. Immunologic evidence of variation in the antigens associated with Hepatitis B, and possibly in Hepatitis A, may explain some well known epidemiologic phenomena and has important implications in immune serum globulin prophylaxis. The ambiguous relationship of antigenemia and viremia in Hepatitis B is explored in relation to the hepatitis hazard of blood products, to trials of immune serum globulin, and to the potential role of the carrier-health worker in hepatitis transmission. The emerging concept of non-parenteral transmission of Hepatitis B is reviewed and future developments in the production of hepatitis vaccines and in experimental viral hepatitis in non-human primates is briefly discussed.     

The characteristics of an outbreak of non-A, non-B hepatitis with a fecal-oral mechanism of the transmission of the causative agent in Osh Province, the Kirghiz SSR

The results of epidemiological, clinical and laboratory studies revealed that the sharp rise of morbidity in viral hepatitides in Osh Province, the Kirghiz SSR in autumn 1987 was caused by hepatitis non A, non B virus with fecal-oral transmission. At this period the results of the enzyme immunoassay showed the absence of the markers of hepatitides A, B and Delta in 72.2% of viral hepatitis patients. Hepatitis non A, non B occurred only in 2.4% of viral hepatitis patients of preschool age (of these, 83.3% had hepatitis A) and was diagnosed in autumn 1987 in 50% of the patients aged 7-14 years and in 97.4% of the patients aged 15-29 years (in the latter age group 95-98% of the patients had IgG to hepatitis A virus in their blood). The appearance of the outbreak of the above-mentioned infection in Kirghizia is linked with the water route of the transmission of the infective agent. The epidemiological and clinical signs, characteristic of fecal-oral hepatitis non A, non B in Kirghizia, were not different from those registered earlier in other republics of the Central Asia and could be used for the identification of this infection.     

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.     

Prevention of acute enteric infections and viral hepatitis A appearing in connection with a natural disaster in the Republic of North Ossetia-Alana

Materials on the work of the sanitary and epidemiological service in the Republic of North Ossetia-Alania, aimed at the prophylaxis of acute enteric infections and viral hepatitis A under the conditions of the emergency situation caused natural calamities (inundation, high flood), are presented. The competent planning and operative realization of organizational, prophylactic and anti-epidemic measures have made it possible to keep morbidity in acute enteric infections and viral hepatitis A on a sporadic level.     

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.     

Etiologic structure of viral hepatitis in children based on data from an comprehensive serologic study of hospitalized patients

During a year an overall serological examination of 1,200 children hospitalized with the diagnosis of viral hepatitis was carried out with a view to establish the presence of hepatitis A and hepatitis B markers (anti-HAV IgM, HBsAg, anti-HBs, anti-HBc and anti-HBe IgM) by means of the enzyme immunoassay and radioimmunoassay. The average annual proportion of cases of hepatitis A (61.4%), hepatitis B (20.4%), hepatitis non A, non B (11.2%) and mixed infection (7.0%) among children, as well as seasonal and age-group fluctuations of this proportion, were established. The etiological structure of viral hepatitides, based on commonly accepted clinico-epidemiological diagnostic criteria, was shown to differ from their true etiological structure as determined in accordance with specific serological markers detected in this investigation.     

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.