The current problems in the epidemiology and prevention of viral hepatitis B and C in the Russian Federation

The data on the epidemiological situation with hepatitides B and C in the Russian Federation in 1991-1998 are presented. Morbidity rates in hepatitis B, registered during the recent 3 years, were 35.8 (1996), 36.3 (1997) and 35.7 (1998) per 100,000 of the population. Morbidity rates in acute hepatitis C were 3.2 (1996), 9.1 (1997) and 11.6 (1998) per 100,000 of the population. Different regions of the Russian Federation were noted to have pronounced differences in the activity of the epidemic processes of hepatitides B and C.     

Spread of salmonellosis in Moscow and the ways of its prophylaxis

The article deals with the results of the epidemiological analysis of the spread of salmonellosis in Moscow. During the last 15 years the proportion of Salmonella enteritidis was about 80% and more. After salmonellosis morbidity decreased to 19.9 per 100,000 of the population (the minimum level) in 1985 its sharp rise was noted. Morbidity rate increased from 31.7 in 1987 to 55.1 per 100,000 in 1988, then to 93.9 per 100,000 of the population in 1989 (the maximum level). In the subsequent years up to 1996 a decrease in morbidity rate was observed, but in 1997-2002 morbidity rate stabilized within 29.8-35.7 per 100,000 of the population without a perceptible tendency towards decrease. The sharp increase of the etiological role of S. enteritidis which led to a wide spread of Salmonella infections was caused by the "chicken-egg" factor of their transmission. High morbidity rate among children and adults, registered all the year round, is the consequence of the constant epidemic activity of this factor.     

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.     

Epidemic process of pertussis in Moscow

Materials reflecting the dynamics of pertussis morbidity during the period of 1958 - 2003 under the conditions of prolonged mass immunization of the child population with adsorbed DPT vaccine are presented. The planned vaccination of children led to the decrease of pertussis morbidity during the first 10 years, but groundless abstentions from vaccination during the 1980s - 1990s contributed to a sharp rise in morbidity among children of younger age groups. During the recent four years a rise in pertussis morbidity was registered in 2000 (71.79 per 100,000 of the population), followed by the most significant for the last 20 years drop in morbidity in 2002--down to 9.89. But in 2003 the growth of morbidity was again registered (38.67). Recently periodic rises and drops in morbidity occurred simultaneously with the increased coverage of children of younger age groups with vaccination. In recent years changes in the age structure of patients were observed: the specific proportion of school children increased (in 2003 morbidity rates in children aged 6 - 10 years were 288.6 - 270.7), simultaneously high morbidity among children aged up to one year (274.9) was registered. The specific proportion of pertussis-affected children aged above 7 years reached 65%. From the late 1990s until present in 87.1% of cases strains of serotype 1.0.3 prevailed in the population of B. pertussis strains. But in recent years the circulation of strains 1.2.3, spread in the prevaccination period and having toxicity similar to that of strains of serotype 1.0.3, while exceeding them in virulence, in sufficiently high proportion (7.0% in 2002) was noted. This was indicative of the possibility of the unfavorable development of the epidemic process of pertussis infection.     

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.     

Epidemiological pattern of scarlet fever in recent years

During the period of 1953-2001 scarlet fever morbidity level fluctuated from 670.3 to 65.9 per 100,000 of the population in Moscow and from 531.9 to 35.0 per 100,000 of the population of the Russian Federation. In recent years an increased morbidity was more pronounced in Moscow than in the Russian Federation as a whole. Children formed the greater part of scarlet fever patients, the cases of scarlet fever among children in Moscow occurring more often than, on the average, in Russia. As before, annual morbidity among children attending children's institutions was higher 3- to 4-fold than among children brought up at home. This difference was most sharply pronounced among young children during the first two years of their life. In contrast to morbidity observed during previous 20-30 years, a drop in morbidity among children during the first two years of their life was registered, while morbidity level among children aged 3-6 years and 7-14 years increased. Scarlet fever morbidity had a pronounced seasonal (autumn-winter) pattern. In a group of children aged 3-5 years who attended organized groups, on the average, 78.6% of scarlet fever cases fell on seasonal morbidity, the most prolonged one.     

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.     

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.     

Epidemiology of hemorrhagic fever with renal syndrome in the north Volga-Viatka region

The results of the ecological and epidemiological study of hemorrhagic fever with the renal syndrome (HFRS) in the Kirov region for the period of 1987-2000 are presented. HFRS morbidity rate varied from 1.3 to 13.7 per 100,000 population, which corresponded to the figures registered in the Volga Vyatka region. Cases of HRFS were mainly (90%) registered in three southern districts of the region. The moderate degree of correlation between morbidity rate and the number of wild mammals (r = 0.55) was established. Periodic morbidity rise occurred every 3 years. In 1998-2000 the contamination of wild mammals with HFRS virus increased and reached 7.6-9.5%. Infection factors connected with everyday human activities somewhat prevailed, industrial and agricultural types of infection constituting 43.8%. Males aged 20-49 years prevailed among the patients. Morbidity rate among urban dwellers exceeded that among town residents.     

An epidemiological analysis of hemorrhagic fever with renal syndrome morbidity in the Republic of Bashkortostan in 1997

The outbreak of hemorrhagic fever with renal syndrome (HFRS) in the Republic of Bashkortostan, resulting in 10,057 registered cases of the disease (287 cases per 100,000 of the population), was analyzed. HFRS cases among the population were registered in 52 out of 54 regions of Bashkortostan. 31% of the total number of patients were the inhabitants of rural regions (170 cases per 100,000) and 69% were urban dwellers (295 cases per 100,000), mainly in Ufa (512 cases per 100,000). HFRS morbidity among males was fourfold higher than among females. In 70% of cases persons aged 20-49 years were affected. 5% of the total number of patients were children aged up to 14 years. In 34 cases (0.4%) the severe clinical course of the disease had a fatal outcome. Cases of HFRS were registered from April 1997 till March 1998 with the highest morbidity rate observed during the period of August-December. In most cases (46.8%) both urban and rural dwellers contacted infection during a short-term stay in the forest. As the result of the serological examination of the patients, all HFRS cases were etiologically attributed to hantavirus, serotype Puumala. The main natural reservoir of this virus and the source of human infection in Bashkortostan were bank voles (Clethrionomys glareolus), the domination species among small mammals in this region.     

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.     

The epidemic spread of the influenza A and B viruses in the USSR in 1985-1986

The data on the spread of influenza A and B in the autumn and winter of 1985-1986 are given. Three epidemics caused by all presently circulating viruses, B, A (H3N2) and A (H1N1), were registered in the USSR. Of these, the greatest one was the epidemic of influenza B; morbidity rate among the adult population during this epidemic was at the level with the morbidity rate characteristic of the epidemics registered at the period of 1962-1972, and morbidity rate among children, especially school children, was even higher.     

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.     

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.     

Viral hepatitis in different population groups of Republic of Sakha (Iakutia)

A survey for the presence of markers of viral hepatitis B, delta, C and E among different groups of the population of the arctic and agricultural zones of the Republic of Sakha (Yakutia), as well as in Yakutsk, was carried out. The survey revealed that viral hepatitides with the parenteral mechanism of the transmission of infective agents were widely spread among the population. In the arctic zone HBsAg was detected in persons aged 20 years and older in 10.8-17.1% of cases. On the average, in the arctic zone antibodies to virus delta were detected in 2.4% of cases. In different regions of the agricultural zone the detection rate of HBsAg was also high (10.4-23.8%). In the Namsk and Vilyui regions delta infection was registered among adolescents (15-19 years of age) in 8.7 and 22.4% of cases respectively. In the Mountainous region anti-delta antibodies were detected among persons aged 20 years and older in 31% of cases. The survey showed the presence of considerable differences in the detection rate of the markers of hepatitis B, depending on the ethnic origin of the examined patients. Similar tendencies were found to exist with respect to delta infection.     

The detection of viral hepatitis markers in HIV-infected patients

The determination of markers of virus hepatitides B, C and D in 63 registered HIV-infected persons was made. The use of Russian and foreign EIA systems permitted the detection of markers of virus hepatitides 30.1% of HIV-infected persons, including 26.3% of children. Markers of hepatitis B virus were found to occur in children and adults with the same frequency. Out of 65 persons registered in the Center, 3 persons (4.6%) were drug addicts; of these, 2 were found to have antibodies to antigens of hepatitis viruses. Such persons constituted 3.8% of the total number of HIV-infected persons. Among 8 newly detected and registered HIV-infected adults, 2 were found to have antibodies to hepatitis B virus (of these, 1 used drugs intravenously).     

The epidemiological characteristics of HIV infection in Turkmenistan

In the presence of the low spread of HIV infection a sharp increase in sexually transmitted diseases is noted. Nevertheless, taking into account a rise in STD, the reality of the potential risk of the spread of HIV is emphasized. Thus, in 1996 morbidity is syphilis was found to grow 7.2 times in comparison with 1992, amounting to 37.5 cases per 100,000 of the population; morbidity in gonorrhea amounted to 32.4 cases per 100,000 of the population with the proportion coming to medical institutions not exceeding 30%. A high proportion of hepatitis B virus carriers was also established (from 15% to 30% of healthy persons), while morbidity in virus hepatitides rose twofold for the period of 1994-1995. During recent years the service for the prophylaxis of AIDS was noted to considerably decrease measures on mass screening. At the same time the article attracts attention to the necessity of increasing the work on the dissemination of information and education on HIV/AIDS drug among addicts, prostitutes and homosexuals. The Draft National Program of the Prophylaxis of HIV infection and STD for 1998-2002 has been worked out. Great importance of methodological and financial assistance rendered since 1994 by international organizations, including WHO, UNFPA, etc., have been emphasized.     

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 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.     

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.